usually < 5 yrs, extreme tenderness, Nikolsky’s sign (involved and uninvolved skin), usu. spares oral mucosa, recovery without scarring, differentiate from TEN

exfoliative toxins A and B, cultures negative, superficial split in granular layer

Toxic Shock Syndrome (TSS) [pic] [pic]

300 cases/yr / ½ from females/tampons / can also be caused by Group A strep

Micro: superantigen, IL-1,2 / TSST 1 similar to enterotoxin B and C (occurs in 20% of S. aureus)

Presentation: fever, vomiting, diarrhea, diffuse erythroderma with desquamation (7-10 d), non-purulent conjunctivitis, hyperemia of mucosal surfaces, myalgia

Rash: almost always seen within first 24 hrs, purpural lesions can even look like RMSF, meningococcemia, cleavage pattern of lesions differentiates from ?strep SS and other causes

Complications: abnormalities of 3 or more organ systems including rhabdomyolysis, encephalopathy, azotemia, elevated ALT/AST, thrombocytopenia

Ddx: TSS from Group A (rarely B) Strep, RMSF, meningococcemia, EM, others

Treatment: anti-staph B-lactams (nafcillin or possible vancomycin until negative nasal swab for MRSA is obtained) and clindamycin for “eagle effect” (large number of organisms reach a slowed growth curve and this lack of cell division necessitates use of anti-anabolic agent such as clindamycin

Supportive: IV fluids and management of sepsis / ?vancomycin for MRSA strains?

Surgical debridement/drainage of any obvious source

Pneumonia

recovery 3-6 wks / CXR resolution by 3-6 months

Food poisoning

preformed toxin, 2 hrs / Pappasito’s Mexican restaurant

Bacteremia

must treat 4-6 wks (with positive cultures) unless you have an obvious source that is quickly removed (see Harrison’s) – otherwise the infection may recur later as endocarditis et al.

Osteomyelitis (see other)

Endocarditis (see other)

Arthritis

MRSA (methicillin resistant Staph aureus)

Current thinking is that nasal carriage predicts MRSA infection / A nasal swab can help

determine whether a person is colonized with MRSA, and guide empiric abx coverage for

presumed or culture-negative S. aureus infection (i.e. if nasal swab is positive, you need to use vancomycin) / it follows that contact precautions may not be all that useful to prevent transmission

Treatment: vancomycin, linezolid, synercid, (sometimes, if sensitive, rifampin, bactrim) / quinolones and carbapenems not effective on MRSA

Note: you can usu. trust sensitivities (e.g. if it says bactrim sensitive, you can use bactrim)

S. epidermidis

catalase +

protective slime / adherent slime / line or device related

S. saprophyticus

catalase +

UTI in young women / more resistant

S. hemolyticus

more resistant

Streptococcus

GP diplococci

Strep pyogenes (Group A)

Micro: catalase negative, B-hemolysis, bacitracin (A disc) / M protein for attachment (anti-M is protective) / anti-phagocytic

Diseases: impetigo, cellulitis (erysipelas), pharyngitis, tonsillitis, purpural sepsis, TSS (exotoxin), necrotizing fasciitis/myositis, scalded skin, septic joint (via transient bacteremia, culture from blood and joint only ~66% sensitive), pyoderma, bacteremia

Reactive: scarlet fever (erythrogenic superAg), rheumatic fever (anti-ASO, streptolysin O), glomerulonephritis, reactive arthritis (not necessarily rheumatic fever)

Clinical: the lymphadenopathy of Staph and Strep infections usu. produces warn, red, tender nodes, but can be cold when the purulence is deep within the node

Treatment: Penicillins (and other)

S. agalactiae (Group B Strep)

CAMP +, B-hemolysis

mother to child via vaginal delivery / pneumonia, neonatal bacteremia, meningitis (esp. neonates), UTI

Treatment: ampicillin

Group C Strep

pharyngitis / bacteremia / endocarditis / (animals)

Treatment: same as Group A Strep

Enterococcus (Group D Strep)

Micro: g-hemolytic (non) / bile esculin / PYR positive / 6.5 NaCl (not other group D)

Diseases:

· Urinary

· Biliary

· Wound

· Bacteremia

· Endocarditis (for PCN allergic patients, some say linezolid not enough,)

Transmission: VRE is generally a nosocomial infection that is selected by prior antibiotic treatment (with vancomycin as well as other agents) and is not a community-acquired infection (people do get colonized by fecal matter contamination)

E. faecium

more commonly resistant to amp and vanc / also has endogenous anti-AG enzyme

E. faecalis

Treatment:

VRE à linezolid and synercid / chloramphenicol, doxycycline may have

some efficacy /evernimycin and daptomycin also in clinical trials?

Non VRE à ampicillin for simple infection / amp + gentamicin for severe infection

· Aminoglycoside resistance

both sp. / high level resistance to gentamicin predicts resistance to all others (except not necessarily streptomycin) / sometimes, Enterococci can have an enzyme that chews up all AG’s except gentamicin

· B-lactamase

only E. faecalis (and but one strain of E. faecium)

· Penicillin resistance

altered/over-production of PBP’s – both sp. / note: if resistant to one B-lactam via altered PBP’s, then it’s usually resistant to all of them

Note: Do Not trust all sensitivities (e.g. never use bactrim even if it says you can, but on the other hand, I have seen some ID people say nitrofurantoin is okay if listed as sensitive) / Note: imipenem does not have enough activity to treat Enterococcal bacteremia

Note on aminoglycosides: some data suggests gentamicin is actually more synergistic than other AG’s (e.g. tobramycin) against Enterococcus

Note on ampicillin resistance: if MIC at 64 ug/ml, and you don’t have access to linezolid, there are reports of using 18-30 g amp a day (to reach 100-150 ug/ml), plus gent and achieving success

Group G Strep

pharyngitis / puerperal sepsis / bacteremia, endocarditis

S. pneumoniae (Pneumococcus)

Micro: optochinin (P disc) / capsule (positive quelling reaction), pneumolysin, a-hemolysis

Diseases: otitis media, pneumonia (rusty sputum), bacteremia (sepsis with anemia), meningitis

type 3 is most severe (can produce abscess, pleural effusion)

Clinical: 30% become bacteremic (can cause dry gangrene [pic])

Diagnosis: culture from sputum, ear, blood (sensitivity ~50%), CSF, sinus / serum PCR may be coming soon

Treatment:

· Pneumonia: ceftriaxone or cefotaxime or cefepime / levofloxacin or moxifloxicin / vanc +/- rifampin

Note: macrolides actually are active against pneumococcus, the issues is that they may be more active in tissue, and not provide adequate blood/CSF coverage (given high propensity of Pneumococcus toward bacteremia)

· Meningitis: must get CSF levels > 10 x MIC / ceftriaxone 2 g q 12

Resistance [NEJM]

Note: about ⅓ are resistant to penicillins (altered penicillin binding proteins), of these, some are also resistant to 3^rd generation cephalosporins (15%), bactrim (30%), meropenem (15%) and erythromycin (15%) / pen sensitivity is not related to sensitivity of cipro (4%), rifampin (1%), chloramphenicol (3%)

Course: improvement in 1-2 days (up to 7 in elderly) / asplenic patients have mortality up to 45%

Vaccine available

Note: the vaccine is effective against many MDR strains (but not all ~12)

S. viridans

Micro: a-hemolysis / polysaccharides adhere

Diseases: endocarditis, dental carries, bacteremia

Treatment: penicillin (1^st), erythromycin (2^nd)

S. (deficient)

satellite around S. aureus (need B₆, L-cysteine)

Diseases: bacteremia, endocarditis

S. milleri

grow in abscesses, blood, wound

Corynebacteria

C. diptheriae

Micro: GPR / H₂S / Elek test / cat+ (tellurite med.) / “Chinese characters” / DT on B-phage (inactivates EF-2) / phospholipase D

Source: cutaneous colonization (humans reservoir)

Diseases: pseudomembranous pharyngitis with lymphadenopathy, Guillain-Barré syndrome, may cause exanthematous rash, DT causes myocarditis, paralysis of soft palate (common) and phrenic nerve (sometimes, requiring mechanical ventilation)

Note: Corynebacterium is often a contaminant of blood cultures

Treatment: macrolides / anti-toxin available for DT

C. ulcerans

diptheroids are commensal for skin, pharynx, urethra / causes mild infection

C. jeikeium

nosocomial infections / bacteremia, endocarditis / use vancomycin

Other GPR

Listeria monocytogenes

Micro: GPR, tumbling motility, catalase + / slight B-hemolysis / internalin, LLO, PLA

can multiply at low temperatures / intracellular (CMI) and extracellular growth

Source: food (dairy, deli meats), animals, human gut

Incubation: 2-6 weeks

Risk factors: elderly, diabetes, renal disease, immunocompromised

Diseases:

Chorioamnionitis (usu. FUO in 3^rd trimester)

Neonatal: early onset (transmitted in utero) à granulomatosis infantisepticum

late onset (birth canal) à meningitis

Bacteremia: steroids, malignancy, AIDS

Meningitis: neutrophilic meningitis (CSF can be negative, but blood culture positive)

Rhombencephalits

Diagnosis: culture blood, amniotic fluid

Treatment: ampicillin (1^st) (Listeria resistant to all cephalosporins) (can add aminoglycoside for synergy; but not rifampin which would decrease efficacy of ampicillin) or bactrim (2^nd)

E. rhusiopathae

Micro: GPR, catalase negative, H₂S

Transmission: mammals, poultry, fish (Wailer’s granuloma) / wound or even oral entry

Diseases: painful violet lesion (common), septicemia, endocarditis, arthritis (less common)

Bacillus

B. anthracis - vaccine available [wiki]

Micro: capsule / animals / soil (spores) / EF, LF, PA / capsule on a different plasmid / endospores introduced into skin via abrasion, inhalation, ingestion then transported to lymph nodes (germination occurs in lymph nodes; then bacteremia)

· cutaneous anthrax (caused by handling infected animals, wool, hides, bioterrorism): small papule at 3-5 days then black and necrotic over 1-2 days [pic][pic][pic][pic][pic][pic][pic][pic] / 20% mortality if untreated (otherwise can be self-limited) / can biopsy and see gram-positive rods

Ddx: ecythema gangrenosum (Pseudomonas), brown recluse spider, plague

Treatment: quinolones (recommended but might not be required)

· respiratory anthrax (bioterrorism)

will progress to sepsis and cardiovascular collapse in 24-48 hrs if not recognized and treated early

Diagnosis: widened mediastinum on CXR, bilateral infiltrates and effusions (which are hemorrhagic on thoracentesis)

Treatment: can use ciprofloxacin, doxycycline plus rifampin, clindamycin but because spores can persist a long time, recommended treatment is doxycycline100 mg bid for 60 days

· GI / oropharyngeal

Prevention: vaccine available

B. cereus

motile, no capsule, ubiquitous / food poisoning (LT) (toxin-mediated disease occurs when heat-resistant spores germinate after boiling; re-cooking before serving may not destroy spores) / emetic illness within 6 hrs of eating, self-limited / heat-stabile (pyogenic)

opportunistic infections (rare)

Neisseria sp.

Neisseria gonorrhoeae

Microbiology: GNR / diplococci / oxidase +, speciate with fermentation, chocolate agar with CO₂ / Thayer-Martin media (inhibits normal flora) / Pili (attach/invade), OPA1 (adhere), LOS (endotoxin/core variability) / switches from invade to evade / OMP1 (endocytosis) / IgA protease

Diseases: urethritis, cervicitis, pharyngitis (from oral sex), anorectal, PID, septic arthritis, disseminated, bacteremia (IV drug users)

Transmission:

Females à male 25% (infected women are often asymptomatic)

Male à female 75%

Incubation: 2-7 days

Presentation:

· arthritis/dermatitis (biphasic illness)

constitutional and migratory arthritis usu. upper extremities (knee, shoulder, wrist, hand), tenosynovitis, vesiculopustular skin lesions
may abate or progress to purulent mono or polyarticular septic arthritis

· causes vaginitis rather than arthritis in prepubertal females (discharge, bleeding, pelvic pain, dysuria)

· causes increased burning/discharge rather than hematuria/retention in males

· meningitis

· osteomyelitis

· conjunctivitis (neonatal)

Diagnosis: blood culture (if disseminated, positive in 50%; usu. only early on), culture of joint usually negative (may be positive late), but gram stain and/or culture (tell lab to use T-M media) of other areas (cervix, urethra, rectum, throat, skin lesions) may be positive // DNA probe // endocervical culture is 80-90% sensitive / test for syphilis and HIV also

Treatment: ceftriaxone 125 mg IM single dose or cefixime 400 mg PO x 1 or doxycycline

100 mg PO bid x 7 d or ciprofloxacin 500 mg PO x1 or ofloxacin 400 mg PO x1

Note: always cover for possible co-existing chlamydia (doxycycline); reverse not true, pts diagnosed with chlamydia do not have to be covered for Neisseria

Note: all newborns (regardless of status of mother) get silver nitrate ointment one time; conjunctivitis would occur day 2-5 (if drops not given); if newborn emerges with conjunctivitis, it is most likely not Neisseria (too soon)

Disseminated Gonococcal infection

Presentation: fever, rash (~nodular) [pic], endocarditis, hepatosplenomegaly / suspect compliment deficiency in chronic cases / females can be chronic carriers

Diagnosis: can culture from synovial fluid (usually not skin) [use normal media]

Treatment IV cephalosporins

Neisseria meningitidis -vaccine available

GNR, 13 serogroups, CSF (high WBC, low glucose) / pilus, IgA protease, capsule / endotoxin / 5-15% are upper respiratory carriers (humans only reservoir)

bacteremia (may cause DIC)
meningitis (mostly children, due to lack of Ab’s) / case fatality rate 13% / ⅓ o ½ with permanent CNS sequelae

Treatment: high-dose ceftriaxone or penicillin G

· chemoprevention for all contacts with rifampin or sulfonamide (about 2-3 days for at risk family members)

Vaccine available (recommended for college dormitories and military)

Meningococcemia – rapidly progressive

subgroup B causes most of outbreaks (not covered by vaccine)

autoimmune disease predisposes patients to meningococcal infection

Anaerobes

-SC fatty acids / no sputum / analysis by GLC / E strips to get MIC (Kirby-Bauer gives false positives)

Gram Positive Rods (spores)

Clostridium

C. perfringens

GPR in pus, double zone of hemolysis / soil, intestinal tract / alpha toxin or enterotoxin

gas gangrene, food poisoning, sepsis (hemolytic anemia)

Risk factors for sepsis: septic abortion, diseased biliary tree, traumatic wound infections, cancer, leukemia, endocarditis, GI AV malformations, or the NEC of newborn

Treatment: new B-lactams (large doses), clindamycin, metronidazole, chloramphenicol (careful of aplastic crisis)

Gastroenteritis

classic food poisoning (incubation 8 to 24 hours)

preformed toxin of C. perfringens / meats, stew, hash

Presentation: gastric pain, watery diarrhea, no vomiting (unlike B. cereus)

Enteritis necroticans (pigbel)

Beta toxin of C. perfringens / high protein meal with trypsin inhibitors (sweet potatoes) in a

host with limited proteolytic activity in intestine

Presentation: acute abdominal pain, bloody diarrhea, vomiting, peritonitis

Complications: small intestine ulcerations

C. botulinum

Source: ubiquitous soil, home canned foods (vegetables, fruit, occ. meat or fish), outbreaks (baked potatoes, day-old stew)

Diseases:

Food-borne: ingestion of toxin à mild gastroenteritis (nausea, vomiting, abdominal pain) / incubation for 18-36 hrs / cranial nerves (blurred or double vision, voice changes) then symmetric descending paralysis, then respiratory failure

Infant botulism from honey (spores germinate in the intestine) causes floppy baby

Wound botulism (rare, 10 day incubation, same disease as food-borne, often from IVDA and intranasal cocaine)

Mechanism: LT neurotoxins A-G (only A,B,E cause human illness) / neurotoxin enters spread hematogenously to cholinergic nerve terminals, NMJ, and ganglia, internalized into neurons, inhibit release of acetylcholine / CNS not involved

Note: toxin is inactivated by cooking

Presentation: dilated pupils / repetitive nerve stimulation gives incremental response

Diagnosis: detect toxin or organism in stool or blood

Ddx: GBS, Lambert-Eaton, polymyositis, tick paralysis, diptheria, chemical intoxication

Treatment: Trivalent horse anti-toxin (made in Los Angeles and Atlanta only) must be given immediately; in absence of ileus, cathartics should be given to purge toxin (GI lavage only if recent ingestion); antibiotics only if ongoing activate infection (not solely toxin)

Course: 20% mortality or self-remission by 1 week

C. tetani

Micro: anaerobic GPR, spore forming (tennis racket)

Source: ubiquitous, soil and feces

Epidemiology: 50 cases/yr, non-immunized

Mechanism: retrograde transport along peripheral motor neuron to brainstem and spinal cord, toxin blocks release of GABA, suppresses glycine release in motor nuclei causing lockjaw (trismus), spasms [pic]

Diseases:

Generalized: onset~7 days / trismus, then shoulders/back, then abdomen/limbs / risus sardonicus, opisthotonos, ANS dysfunction

Neonatal: unsterile treatment of umbilical cord stump / generalized spasms in first two weeks of life IP

Local

Diagnosis: clinical / serum antitoxin levels ( > 0.01 is protective, and also rules out Tetanus)

Treatment: tetanus immune globulin (TIG) / flagyl (penicillin is 2^nd line as it may antagonize GABA) / BZ for spasms, supportive care (tracheostomy, quiet room)

vaccine available

C. difficile

pseudomembranous colitis or C. difficile associated diarrhea (CDAD) / can happen with even one dose / wide range of severity / 50% of people are carriers of non-toxin producing strain (geographical component)

Presentation: frequent, loose, foul-smelling stools, abdominal cramps / can have some blood, but usually not frank hematochezia / fever usually low-grade (can be high) /

Prevalence: 3% of healthy adults are colonized; 20-40% of hospital patients are colonized

Diagnosis:

· cytotoxin A or B (in stool) / very insensitive; requires multiple samples

· fecal leukocytes (usually positive)

· flexible sigmoidoscopy [pic][pic] (can miss only proximal lesions; 10% of cases spare rectum; 50% have pseudomembranes in colon)

Complications: loss of fluids, albumin, electrolytes / can get polyarthritis (rare) / osteomyelitis (nosocomial) / watch out for toxic megacolon with perforation

Treatment: Guidelines from the American College of Gastroenterology

· PO or IV metronidazole 250 mg qid for 10 days (I say 14-21)

· PO (not IV) vancomycin (trend now is to use PO vancomycin 1^st line if possible 9/06) / some studies show benefit of adding rifampin

· NEW tactic to prevent relapse: follow initial CDAD treatment with 2 wk “chaser” course of rifaximin

· if possible avoid/stop antibiotics active against normal GI flora (of course, GNR coverage will be necessary if patient does perforate)

· replace fluid and electrolyte losses, avoid antiperistaltic agents (duh!)

· some advocate cholestyramine or colestipol to attempt to bind toxin in gut

Note: relapse is treated with same agents (resistance is not the issue, but perhaps ½ of relapse is with different strains)

Note: do not treat asymptomatic patients colonized with C. difficile

Course: mortality 5-10% of those affected / should improve within 48-72 hrs but relapse is common (5-15%), often occurs early, risk factors: age, surgery, leukocytosis, CRF, females, spring time infection / how to prevent relapse/recurrence (always under investigation)

Note: patient needs to be in contact isolation

Note: North American isolate is emerging 9/06 à more virulent, responds better to PO vancomycin (recommendation now is to change if 2 days metronidazole does not show improvement)

C. septicum

Suppurative deep tissue infections

· Intraabdominal abscess, frostbite and gas gangrene, stump infection

· Female genital tract, especially pelvic abscess

· Emphysematous cholecystitis

Skin and soft tissue infection

· Wound contamination (no antibiotic treatment needed)

· Cellulitis (heroin addicts)

· Fasciitis (rapid progression, massive hemolysis due to toxin)

· Myonecrosis (gas gangrene) needs surgery

Bacteremia

· C. perfringens bacteremia usually transient and benign / look for other predisposing factors or illness elsewhere

· C. septicum bacteremia associated with intestinal malignancy (like S. Bovis)

· primary pathogen of neutropenic enterocolitis

Diagnosis: culture and clinical findings / X-rays showing gas

Treatment: PCN plus clindamycin / surgery / hyperbaric oxygen

Gram Positive Rods

Actinomyces oral, GI, soil

Proprionibacterium skin flora

Lactobacillus vaginal flora

Eubacterium colon

Gram Negative Rods

Bacteroides fragilis

colon / B-lactamase

abscesses in peritoneum / endometritis

Micro: bile / safety pin appearance / SOD / catalase +

Treatment: new B-lactams (pip/tazo, meropenem, cefotetan, cefoxitin), clindamycin, flagyl, chloramphenicol

Prevotela

Vitamin K and hemin

oral / aspiration pneumonia / B-lactamase

Fusobacterium necrophorum

needleshape morphology [pic] / oral / lysis tubes help for culture / aspiration pneumonia / same + penicillin G

leukocidin, hemolysin, platelet aggregation

Lemmiere syndrome (also Prevotela, Peptostreptococcus, Eikenella) (see other)

Gram Negative Cocci

Veillonella

gram stain/failure to grow

abscesses from aspiration or trauma / URI, GI, GU

Treatment: penicillin G, etc.

Gram Positive Cocci

Peptostreptococcus

gram stain/failure to grow

abscesses from oral, skin, GI, GU

cannot use penicillin G if B. fragilis is present

metronidazole not effective

Gram Negatives

Enterobacteriaceae

Lactose fermentation: this information is useful because it may come back before the actual species/susceptibilities are determined

non lactose fermentors (Shigella, Salmonella)

lactose fermentors (E. coli, Klebsiella, SPACE bugs)

-MacConkey selects enteric bugs with bile salts/gram negative/lactose + turn pink (less pathogenic)

-APE tests color change/gas production

-serotyping below species level - O cell wall / H flagellar / K capsular

-resistance unpredictable / K1 causes neonatal meningitis / oxidase - / catalase -

-virulence factors: endotoxin, capsule, phase variation, exotoxins, adhesion factors, growth factors, resistance, antibiotic resistance plasmids

Shigella

Pathology: large intestine, non-motile, does not penetrate beyond epithelium / intra/extracellular replication

Epidemiology: humans are the only reservoir / very low ID50 (only need a tiny amount)

Course: 1-4 days incubation / severe febrile illness, bloody diarrhea / can cause tenesmus in distal colon

Complications:

· Hemolytic Uremic Syndrome (HUS), Seizures (produces a neurotoxin), Toxic Encephalopathy (rare, rapid, watch for headaches), Ekari syndrome (overwhelming shock and collapse, unrelated to fluid loss, toxin-mediated)

· Toxic megacolon

· Reiter’s (HLA B27, more in adults than children & more common than reactive arthritis)

· Vaginitis

· chronic diarrhea with malnutrition (less in US)

Labs: serum chemistries, low CO2, acidotic, low bicarbonate

CBC with differential (often produces bandemia)

Fecal leukocytes – may get false negatives

Fecal Blood – watery then bloody or always bloody

Stool culture – rectal swab, 50% positive

Treatment: must be careful with anti-motility agents – in adults, they can relieve cramps when given with antibiotics (just be careful not to give with C. difficile) / and do not give them without antibiotics / rehydration, TMP-SMX (some resistance), Suprax (cefixime), ceftriaxone, quinolones

Shigella dysenteriae

Shiga toxin (neurotoxin) / most severe disease / more in developing countries

Shigella sonnei (causes most shigellosis in U.S.)

S. flexneri (Africa)

Sensitive to ciprofloxacin, ceftazidime, cefotaxime, cefoxitin / one study of resistance to ampicillin (82%), chloramphenicol (73%), tetracycline (97%), co-trimoxazole (88%)

S. boydii

Salmonella

Lab: stool culture, motile, lac-, suc-, H₂S

Transmission: fecal-oral, uncooked meat and dairy products (high ID50), pet rodents

Pathology: invade mucosa / gastroenteritis, even bacteremia

Clinical: leukopenia, bradycardia (or relative bradycardia)

Complications: meningitis, arthritis, osteomyelitis (sickle cell patients), infect aneurysms

Treatment: antibiotics may prolong carrier state (only treat systemic infections)

Salmonella (non-typhoid)

More in children, animal reservoir, sanitation, summer peaks, food-borne, infectious dose is high, gastric acidity is protective

Note: immunocompromised (HIV, sickle, cancer) more likely to become bacteremic (often without GI symptoms)

Treatment: usually self-limiting in adults, antibiotics, other?

S. typhi

travel outside US

Mechanism: invasive, survives in phagocytes, proliferation in Peyer’s patches, transient bacteremia, seeding of RES/distant sites

Diseases: enteric fever (rose spots on lower chest, abdomen) / chronic carrier in biliary tract

Presentation: usually presents as fever of unknown origin (FUO)

Labs: transient positive stool cultures

Treatment: chloramphenicol / ampicillin / TMP/SMX

S. enteritica (serotype Typhimurium) (same thing as below?)

Transmission by human-human, and pet rodents [NEJM]

May have multidrug resistance

S. enteritidis

milder version / can also seed bloodstream

· Study à azithromycin, cefixime not that useful for uncomplicated S. enteritidis

· quinolones and new macrolides might be useful

S. choleraesuis

most common cause of septicemia

Treatment: chloramphenicol, ampicillin, TMP/SMX

E. Coli

most common cause of UTI / K1 neonatal meningitis / GN septicemia (ceftriaxone?)

Treatment (except EHEC): ampicillin (60-70%), amp/sul (80%), cipro, cephs, all broad spectrum B-lactams, TMP/SMX

Note: some E. coli strains can get pretty nasty and even require carbapenems

EHEC Hemorrhagic (large intestine, distal ileum)

0157:H7 / verotoxin (Shiga-like STx 1 or 2 – blocks EF-1 binding 60s), EHEC-hemolysin, heat-stabile enterotoxin / A & E lesions

Transmission: fast food burgers, beef products, raw milk, fecal-oral

Course: 4 days after exposure (range 1 to 8 d), watery diarrhea, intense abdominal pain, followed 1-2 days later by bloody diarrhea, fever is not prominent, 3-10 day resolution, infectious shedding (up to 3 weeks)

Complications: Hemolytic Uremic Syndrome (HUS) (5-10%, mostly < 5 yrs) (circulating toxin)

Treatment: some think patients with bloody diarrhea are put at increased risk for HUS with abx (i.e. don’t treat with antibiotics)

ETEC Toxic (small intestine)

CFA Pili / heat-stable (ST, cGMP) and heat-labile, cholera-like (LT, cAMP) / strains may have one (less severe) or both plasmids (most severe diarrhea)

Course: profuse, watery diarrhea // commonly causes post-infectious irritable bowel syndrome (occurs in 10% of ETEC cases during 6 months following)

Montezuma’s/Traveler’s Diarrhea (immunity to develops to CFA and LT)

primary cause of infant diarrhea / fever is not prominent

Prevention: rifaximin prophylaxis reduced incidence by 5x

Treatment: rehydration therapy, TMP/SMX (bactrim) or quinolones

EPEC Pathogenic (small intestine)

foes not have pili / BFP and intimin (homologs in Yersinia, EHEC, etc.)

A & E lesions cause watery diarrhea, fever (sometimes) (usually self-limiting, chronic in infants)

Nursery outbreaks / childhood diarrhea in developing countries

Treatment: TMP/SMX (bactrim) or quinolones

EIEC Invasive (large intestine)

Facultative intracellular/endocytosis causes inflammation, ulceration, necrosis

Similar but less severe than Shigella (mostly in children under 5 yrs) / fever +

Treatment: TMP/SMX (bactrim) or quinolones

EAEG Aggregative

Watery diarrhea, epidemics, prolonged diarrhea, developing countries

Klebsiella pneumoniae

Micro: non-motile, lactose + / encapsulated (India ink) / intestinal flora

Diseases: 3% of acute pneumonias / 2^nd leading cause of UTI / more in infants, elderly, alcoholics, immunocompromised

· Friedländer's pneumonia: upper lobes, currant jelly sputum, early to abscess, rapid decline

Treatment: very important, depends on whether organism has ESBL (extended spectrum b-lactamase) gene / if so, the in vitro sensitivity to cephalosporins will be misleading, and no cephalosporin will be effective / in these cases, the drug of choice is meropenem/imipenem and possibly double coverage with a quinolone / in non-ESBL strains, one might get by with amp/sul (80%), cipro, carbapenems

Klebsiella oxytoca

being studied as potential causative organism in C. difficile-negative cases of antibiotic-associated colitis 11/06

SPACE Bugs and friends

· intestinal flora that cause nosocomial infections (IV lines, etc.)

· must be treated with 2 antibiotics such as a cephalosporin (cefepime) + aminoglycoside (GM or tobramycin)

Serratia

Proteus

Acinetobacter

Citrobacter

Enterobacter

Serratia

often MDR to penicillins, cephalosporins and aminoglycosides

Treatment: amikacin, newer B-lactams, quinolones

Proteus

10% of uncomplicated UTI’s / also produces urease, which raises pH and produces Struvite

stones or “staghorn calculi”

diseases: UTI, wound infection, septicemia

Treatment: amikacin, newer B-lactams, quinolones

Acinetobacter

Extremely rare cause of community-acquired pneumonia (associated with bacteremia) / nosocomial acinetobacter pneumonia is not associated with bacteremia

Citrobacter

enteric flora, causing opportunistic infections (not diarrhea) / citrobacter can often cause brain abscesses associated with neonatal meningitis

Enterobacter

Must hit 2 different targets to treat this very resistant organism (must have synergy)

Cell wall: cefepime (not the others: you cannot use 3^rd generation cephalosporins no matter what

the c/s says because they will turn on the genes during therapy, under pressure), tic/sul, pip/tazo,

aztreonam, meropenem, ?vancomycin

Protein synthesis: AG gentamicin, tobramycin, amikacin (less chance of AG resistance),

streptomycin

Others: can use bactrim and cipro if c/s reads sensitive

Rifampin?

Providencia

Common cause of catheter associated UTI’s (nosocomial UTIs)

does not produce uricase, most resistant to antibiotics /

Morganella

Vibrios

gram negative, oxidase +, facultative anaerobes, marine

single polar flagellum vs. peritrichous (E. coli, Salmonella)

Vibrio cholerae 01

Micro: grow in 0-1% NaCl, yellow colonies, sucrose + on TCBS

non-invasive, often no fever, 8-72 hr incubation, severity depends on host

Toxin: LT-like choleratoxin (ADP-rib. of Gs)

Treatment: oral rehydration / maybe tetracycline / vaccine promising

V. parahaemolyticus

~ invasive / halophilic, seafood / enterotoxin, 5-24 hr incubation à watery or bloody diarrhea

V. vulnificus

lac + / invasive / ingestion: fatal sepsis with liver disease (hemochromatosis), diabetes,

immunosuppressed / wound infection (gangrene) / mortality up to 50% in

V. alginolyticus

septicemia or wound infection

V. damsela

Gulf Coast / toxin / may be rapidly fatal / septicemia or wound infection

Campylobacter

microaerophilic, non-fermenting, non spore forming, not halophilic, 0.45 microns (tiny), grows at 45 degrees / highly antibiotic resistant

C. jejuni

Source: GI tract of animals / often spread by undercooked meats (retail poultry >> beef) or direct contact with infected animals

Disease: similar to salmonella / usu. self-limited enteritis (watery or gross bloody stool; appears identical to IBD on biopsy) but can lead to bacteremia

Complications:

· local suppurative infections (peritonitis, pancreatitis, endocarditis, cystitis, meningitis, septic arthritis)

· 1 in 1000 cases leads to GBS

· recurrence in 5-10% of untreated patients (much more likely to be confused for chronic, relapsing case of IBD than other GI pathogens)

Diagnosis: clinical, culture from stool, fecal leukocytes (ETEC and viruses usu. do not have fecal WBC)

Treatment: clindamycin (1^st) / often resistant to quinolones / sometimes bactrim can work (but often resistant to that too)

C. fetus

found in sheep and cows / bacteremia in immunocompromised patients

resistant to humoral immunity

Helicobacter pylori (type 1) vaccine promising?

GNR, spiral, microaerophilic / urease positive (breath test), attachment

vac A (vaculating cytotoxin) / mostly asymptomatic / host response damages tissue

gastritis, peptic and duodenal ulcers / may lead to carcinomas, lymphomas

Treatment: tetracycline or amoxicillin, metronidazole, bismuth subsalicylates

H. cinaedi

Causes gastroenteritis, bacteremia, soft-tissue infections, pericarditis/myocarditis / fecal-oral, well-water, hamsters / can be resistant to FQ and AG / likely sensitive to meropenem

Haemophilus

GNCB, non-motile, oxidase +, facultative anaerobes, obligate parasites

requires chocolate agar - hematin (factor X), NAD (factor V), and CO2 for growth

use HMW1,2 and pili to adhere to epithelium / LPS / IgA protease / Hib has PRP capsule

encapsulated: meningitis, conjunctivitis, epiglottitis, arthritis (last 3 maybe for other one)

unencapsulated: otitis media (2nd to pneumococcus), sinusitis, pneumonia, bronchitis

H. influenza

Vaccine widely used

causes purulent meningitis (children under 5), epiglottitis / most children are non-Hib carriers

T-cell immunity doesn’t work well until 18 months / maternal Ab’s work up to 2 mos.

PRP conjugate vaccine given > 2 months / prophylaxis with rifampicin

Treatment: cefotaxime

-H. ducreyi chancroid genital ulcers [pic]

-H. parainfluenzae upper and lower respiratory infections

-H. haemolyticus upper and lower respiratory infections

-H. aegyptius conjunctivitis

Moraxella catarrhalis

GNC / otitis media in children / typical pneumonia in adults / common colonizer in chronic lung diseases (may consider pathogenic on sputum if WBC > 25 and epithelials < 10)

Treatment: cephalosporin or amp/AG

Bordetella pertussis (see pediatric ID)

GNCB, strict aerobe, non-motile, chocolate agar

A-B toxin (cAMP) / invasive AC, tracheal cytotoxin, dermonecrotic, LPS / adherence:

pili, Fha, pertactin / coordinated transcription (BvgS his kinase, BvgA response regulator)

colonize ciliated mucosal cells (humans only reservoir) / infection worst in infants (may be afebrile

3 stages: catarrhal 1-2 wks / paroxysmal (whooping cough) 2-4wks / convalescent

Labs: WBC 20-30 with high lymphocyte fraction

Acellular vaccine commonly used (DTaP)

Treatment helps only stage one (erythromycin 5-7 days)

Legionella

GNCB (maybe AFB), aerobic / multiply inside macrophage and lyse it (cell mediated immunity)

19 species / L. pneumophila (85 to 90% of cases), followed by L. micdadei (5 to 10%), then L. bozemanii and L. dumoffii

Transmission: water source, aerosolization / (not person-to-person) / late summer and early fall

RF: middle-aged man, smoking, alcohol, immunosuppression

Diseases:

1. asymptomatic

2. Pontiac fever: self-limited, flu-like illness without pneumonia

3. Legionnaire’s disease (20% mortality) / pneumonia / 1-8% of community-acquired pneumonias that result in hospitalization / 4% of lethal nosocomial pneumonias / clue is pneumonia + GI symptoms

4. rare localized soft tissue infections

Presentation: incubation: 2 to 10 days / prodromal phase (malaise, fever, headache, and myalgias, cough initially nonproductive, then mucoid)

More common: high fever (sometimes with relative bradycardia), and diarrhea is common (stool is guaiac negative and no fecal WBC)

Less common: altered mental status with confusion, lethargy, or delirium (normal LP)

Complications: bacteremia (38%) and can cause myocardial abscess

CXR: unilateral, patchy segmental or lobar alveolar infiltrate / can progress to bilateral with pleural effusions / occasional lung abscesses and multiple rounded densities suggesting septic emboli

Labs: WBC 10-15 / hyponatremia (more likely than other atypical pneumonias), hypophosphatemia, and elevated ALT/AST / occasionally microscopic hematuria, sometimes with impaired renal function

Diagnosis: urine Ag (86% sensitivity, 99% specificity), BAL Assay (46% sensitivity)

1. urine Ag – remains positive long after treatment initiated, only detects serogroup 1 (80% of strains)

2. culture (may grow from any fluid collected, including blood) / 30-70% yield (must use BCYE agar)

3. direct immunofluorescent Ab stain of sputum, exudates (DFA staining is specific but not sensitive)

4. serology (4-fold rise, but usually it occurs already well into illness)

Course: 15% mortality (even with treatment) / slow convalescence of CXR

Treatment: fluoroquinolones or macrolide ?+/- rifampin / duration over 3 weeks / IV can be changed to oral after acute symptoms have resolved

Pseudomonas aureugenosa

GNR, aerobe / lactose -, oxidase + / pyocyanin (blue-green pigment) / endotoxin A (EF-2)

Diseases: wound, burn, UTI, pneumonia (cystic fibrosis), osteomyelitis / sepsis (black? skin lesions) / hot tub folliculitis / external otitis (swimmer’s ear) – especially in older patients with DM

Ecythema gangrenosum

round/oval, 1 to 5 cm, raised halo/rim of erythema/induration surrounds central area, a vesicle that evolves into a necrotic ulcer / occurs in 5-20% of pseudomonal bacteremia (and also aeromonas and several other bacteria)

Treatment:

Cefepime + AG (+++ synergy) [probably the best for resistant strains]

Zosyn or Timentin + AG (++ synergy)

Ceftazidime/ceftriaxone + AG (+ synergy)

Meropenem [good coverage, ?synergy]

Ciprofloxacin [good if sensitive]

Aeromonas hydrophila

Myonecrosis / Sepsis / endocarditis

aeromonas / resistant to many antibiotics use quinolones

Stenotrophomonas maltophilia

Nosocomial infection (pneumonia, UTI, wound infection, bacteremia)

Resistance: usually resistant to imipenem, pip/tazo

Treatment: drug of choice IV Bactrim, also ticarcillin/CA (Timentin)

Burkholderia pseudomallei

Causes melioidosis / water, soil in SE Asia, N. Australia, Central and S. America / can infect any organ, but most likely lungs / can be latent for months to years with reactivation in form of chronic pneumonitis

Burkholderia cepacia

opportunistic pathogen (cystic fibrosis, sickle cell, chronic granulomatous disease) / nosocomial outbreaks / may cause necrotizing pneumonia

Resistance: highly resistant to many B-lactams and AGs

Treatment: bactrim

Mycobacterium

Mycobacterium tuberculosis (MTB) [non-tuberculous mycobacteria]

Micro: slender AFB, non-motile, obligate aerobe / droplet nuclei in milk, wounds (rarely)

Pathology: 90% asymptomatic exposure / 90% active TB are reactivated cases (90% pulmonary)

MTb first settles mid/lower lung / may become walled off in apex of lung, bone, kidney, brain

Infectivity: not coughing reduces infectivity / takes about 1 month to become smear negative on 4 drug therapy (no differences in AIDS pts) / droplet precautions should be practiced / document negative sputum smears before moving out of isolation (hospital, work, half-way house)

Babies contacted at home given 3 months INH before completing work-up

Presentation:

· fever, night sweats, malaise, weight loss, hemoptysis

· pleural effusion (30% with negative PPD, most have spontaneous resolution, high eosinophils, low mesothelial cells)

· Rasmussen aneurysm (rupture of dilated vessel in cavitary lesion)

· systemic disease (arthritis, meningitis, rashes) (see disseminated)

Specific syndromes:

· Primary Tb

· Reactive Tb

· Miliary Tb (disseminated Tb): 1-2 mm granulomas

· Pott’s disease (spine): osteoarticular Tb usu. has radiographic changes

· Scrofula (cervical nodes)

· Reactive Tb: Poncet’s (arthritis) / organism not in joints

· Adrenal tuberculosis: cause of primary adrenal insufficiency

Labs: can have lymphopenia (which can be a true state of immunosuppression, just like AIDS), leukocytosis, anemia, hyponatremia (SIADH)

Diagnosis:

Culture: must have for definitive diagnosis (Zhiel-Neelson/Kinyoun) / granuloma formation may be prevented by immunosuppression / culture takes about 3 to 6 weeks

· Note: new technique called MODS (microscopic-observation drug-susceptibility) only takes 7 days and has 97% sensitivity (but only available now in very specialized labs 10/06)

AFB stains for CSF have very low sensitivity / get as many early morning AFB samples as you can (as cultures may not grow) / beware of M. Saphrophytes from water, upper GI, urinary

PCR – low sensitivity / mainly useful to distinguish different mycobacterial sp. (not initial diagnosis) / check CSF, ascites, ?pleural effusion

ADA (enzyme) – elevated with Tb / check in CSF, ascites, ?pleural effusion, ?blood

CSF: 10-500 WBC / glucose 20-40 / protein 4000-5000

may have left shift early on and then lymphocyte predominance later (like viral)

Pleural effusion: 20-30% culture yield [leave some fluid in case you need to take a biopsy later, which has a 60% yield and 80% with multiple biopsies]

Skin Testing [pic] (Mantoux positive [pic] at):

≥ 5 mm (HIV or immunocompromised or close contact)
≥ 10 mm (at risk: diabetes, ESRD, blood disorders, IVDA, rapid weight loss)
≥ 15 mm (normal)

Note: sarcoid, lymphoma, immunosuppression may cause anergy / up to 20% of cases may have negative skin testing even with normal immune system

Note: HIV converters have 15%/yr chance of developing Tb whereas normal is 3%/yr

Note: new test called IGRA may be better for detecting latent Tb (esp. in BCG-exposed patients)

CXR: classical teaching is apical à recurrence and atypical à primary infection; however, the most important factor in CXR appearance is host immunity status

CT can help distinguish disseminated tuberculosis vs. lung metastases and diffuse interstitial diseases [CT] [CT]

Ddx: M. kansasii, many others

Treatment: (see TB drugs)

Chemoprevention (for patients with positive PPD and no active disease): 6-12 months INH (some say treat all pts < 35 yrs with no contraindications to INH)

Active TB: INH + rifampin + PZA + ethambutol for 2 months then INH + rifampin for 4 months

Note: fever resolution at 1 week of treatment for regular TB (85%), MDR TB (50%), MAC (20%) / rapid defervescence does not rule out MDR strains

Resistance: growing (often occurs in people from TB prevalent countries) / treatment failure = positive cultures after 3 months or positive AFB stains after 5 months

Disseminated mycobacteria (as in HIV/AIDS)

Major cause of FUO in HIV/AIDS pts / Tb is more common in HIV as consequence of immunosuppression (not necessarily from co-infection and/or socioeconomic factors)

Presentation: lymphadenopathy, miliary Tb in lungs, mucosal ulcers

Note: microabscesses detected by high resolution but not conventional ultrasound, also useful for follow-up (90% resolution of microabscesses after clinical resolution)

Ddx: M. tuberculosis, M. kansasii, M. genavense, M. intracellulare, M. haemophilum, M. simiae, M. celatum, M. malmoense, M. marinum, and rapidly growing mycobacteria

Differentiating sputum positive AFB infections

MAI: lower CD4 count, dyspnea, normal CXR

Blood cultures positive in MTB (58%) and MAI (80%)

Liver biopsy (70%) sensitivity

Note: in cases of suspected pulmonary infection, a single culture can be a colonizer (esp. in patients with abnormal lungs) rather than active infection (except M. kansasii is usually pathogenic) / One study (n=34): 20 MTB (1/2 disseminated), 9 MAI (⅓ disseminated), 3 M. kansasii, 1 M. malmoense, 1 M. fortuitum

M. Avium-Intracellulare

· AIDS / disseminated disease or focal infection

· Lady Windermere syndrome / elderly women, chronic, indolent cough

Diagnosis: stool culture for MAI (GI is most common route of entry), blood culture, tissue biopsy (best for definitively proving active, focal infection)

· CXR/CT: may show small nodular infiltrates cylindrical bronchiectasis / often middle lobe involvement

Treatment: multi-drug resistance is expected / may take several months up to an entire year of ethambutol and clarithromycin (or azithromycin) / add streptomycin/amikacin (if really sick) / may also add rifampin

· Note: prophylactic doses with disseminated MAI will only generate resistant MAI / if you’re not sure about diagnosis, either treat or don’t treat and wait for positive blood cultures

M. lepra

AFB enters the skin?

Transmission: men, milk, insects, armadillos

Presentation: nerve involvement / lymphadenopathy

Lepromatous: failed cell-mediated immunity, bad prognosis

Tuberculoid leprosy: self-limited disease / associated with vitiligo (anesthesia, anhidrosis, alopecia) / biopsy reveals granulomas

Treatment: long-term oral dapsone or clofazimine, dapsone, rifampin

Non-Tuberculous Mycobacteria (NTM)

Note: all produce B-lactamase

Diagnosis: rapid detection with DNA probe (ask lab, often can do Tb, MAI, M. kansasii, M. gordoneii)

· Rapid growers (2 weeks): M. abscessus, M. fortuitum, M. chelonae

· Slower growers (4 weeks): M. avium complex, M. kansasii, M. terrae/M. nonchromogenicum complex

M. smegmatis

UG flora

M. kansasii

pulmonary infection (similar to MTb) / still need PMN’s / 18 months of INH 300 mg/day, rifampin and ethambutol / alternative: clarithromycin

M. fortuitum

bone and soft tissue / can become disseminated in compromised host affecting lungs, joints, and even CNS / soil, dust, water, instrumentation (catheters, surgery) / rapid grower

Treatment: clarithromycin, amikacin, doxycycline, bactrim, cefoxitin, imipenem, some quinolones

M. scrofulaceum

cervical lymphadenitis in children / pulmonary disease / superficial, skin infection

M. marinum

fish tank granuloma / grows in cold temperatures / 1-2 months (usu. 2-3 wks) after contact / small, violet nodule at site of minor trauma / can be self-limited

Ddx (for finger-hand-arm): cellulitis (staph or strep), finger-hand-arm disease, Vibrio, M. marinum, E. rhusiopathae, Sporothrix

Treatment: surgical debridement / clarithromycin or minocycline or (rifampin + ethambutol) / some success with bactrim, doxycycline

M. haemophilum

Infects skin and soft tissue in immunocompromised patients / clarithromycin and rifampin

Rhodococcus equi

AFB / causes cysts (can be size of basketball in some medical journals)

Actinomyces

filamentous GPR or AFB, grows slowly in anaerobic or microaerophillic (EOS) / infection may disregard normal fascial planes causing sinus tracts

Source: oral, GI flora, soil

craniofacial abscesses (lumpy jaw)
genito-urinary/chronic
pneumonia / head/neck à thorax (unless traumatic entry)
sulfur granules (purple lesion, fistula, painless)
Whipple’s disease

Labs: cultures will often be contaminated with GNRs

Treatment: penicillin (at least one year, high dose; first 2-6 weeks IV) / tetracycline / surgery if needed

Nocardia [NEJM]

GPR, weakly AFB branching, beaded rod, aerobic

Transmission: from soil to lungs, skin (wounds), CNS

Diseases:

· Pneumonia – cavitary lesion on CXR, thick sputum, fever

· CNS

· disseminated infection (immunocompromised) / must always be on guard for this possibility (brain, kidneys, bones, skin, muscle)

Note: one third of patients are immunocompetent

Diagnosis: silver staining of tissue specimens / actually does often grow on routine lab mediums (2 to 7 days; so must notify lab of suspicion)

Treatment: sulfadiazine or sulfisoxazole 6 to 8 g/d qid up to 12 g/d / others: TMP/SMX, minocycline, amikacin / B-lactams not as well studied

· duration of treatment: 6 to 12 months

N. asteroides 80-90% of cases

N. brasiliensis

N. farcinia

N. nova

N. transvalensis

Chlamydia

most common infectious disease in U.S.

obligate intracellular parasite (no cytochromes or ATP synthetase) - relative bradycardia

non-motile, no pili, no peptidoglycan wall (lacks muramic acid)

EB (elementary body, small/infectious) / RB (reticulate body, replicates by fission) / 24 hr life cycle is why you have to have antibiotic levels for a long time

antigen detection by IF, Giemsa, DNA probe / culture difficult, slow, insensitive

Chlamydia trachomatis

Transmission: human sexual transmission or vertical

ABC cause trachoma

· UTI

§ endocervicitis – most common presentation mucopurulent

§ acute urethral syndrome (most common cause of nongonoccocal urethritis (NGU) in men

§ acute dysuria, pyuria, voided urine < 10e5 / non-GC urethritis that may remain asymptomatic (PID, infertility) / must differentiate from HSV

§ nonpuerperal endometritis

§ acute salpingitis

§ postpartum endometritis

§ neonatal pneumonia, conjunctivitis, otitis media: 25-75% transmission rate / presents at 3-4 months / types D-K / macrolide treatment in children – 1^st course 80% effective

§ LGV: types L1-3 (positive Frei test)

· Conjunctivitis: must swab cells on lower eyelids

· Arthritis (see Reiter’s)

· Conjunctivitis: must swab cells on lower eyelids / major cause of neonatal blindness in Africa

· Diarrhea

Treatment: azithromycin 1g PO x 1 [GI upset with huge dose] or doxycycline 100 mg

PO bid x 7d or erythromycin 500 mg PO qid x 7d or amoxicillin 500 mg PO tid x 7-10d

Chlamydia psittaci (psittacosis)

Diseases: pneumonia, abortions

Source: mainly infected psittacine birds (parrots, parakeets, lovebirds), less often in poultry, pigeons, and canaries, and occasionally in snowy egrets and some seabirds (e.g., herring gulls, petrels, and fulmars) / note: bird is sick too

Transmission: inhalation of dust from feathers/excreta or being bitten by infected bird / human à human is rare (coughing, venereal) / incubation: 1-3 wks

Presentation: abrupt or insidious fever, chills, malaise, anorexia then variable cough / wk 2, pneumonia with consolidation / temperature stays high 2-3 wks then slowly falls / may have splenomegaly

Diagnosis: clinical picture +/- serology

· CXR: pneumonitis radiating from hilum

Pathology: pneumonitis with mononuclear cell exudate (similar to Mycoplasm, viral, Q fever)

Ddx: influenza, typhoid fever, mycoplasma, legionella, Q fever

Treatment: tetracycline 250-500 mg qid or doxycycline 100 mg po bid

Prognosis: improvement usually within 48 to 72 h (continue antibiotic at least 10 d) / untreated mortality from 30% and higher (severity depends on host and virulence of strain)

Prevention: avoidance of birds and infected people / imported birds often get 4-5 course of tet-feed.

Chlamydia pneumoniae

human (aerosol) / pneumonia, pharyngitis?, relative bradycardia / doxycycline, azythromycin or erythromycin

Treatment: clarithromycin for neonates

Zoonotic Diseases (all may be aerosols / facultative intracellular)

Francisella tularensis (Tularemia)

Presentation: localized or disseminated rashes / humoral and cell-mediated response / relative bradycardia, causes RES granulomas

Micro: GNCB, aerobe, facultative intracellular

Transmission: ticks, deer flies / less commonly (infected meat, animals bites (rabbits), water, aerosol) / infecting does very low 10 - 50 (can penetrate skin) / oral challenge requires 10e8

Course: incubation (2-5 days) / primary (1-4 days) / remission (1-3 days) / chronic relapse (2-3 weeks)

Primary Diseases: ulceroglandular (45%), enteric tularemia (5%), pulmonary tularemia (via inhalation)

Complications: oculoglandular, meningitis, endocarditis, osteomyelitis, pneumonia (primary or sequela)

Diagnosis: there is an agglutination assay (culture is dangerous, difficult)

Treatment: streptomycin, tetracycline or chloramphenicol (up to 30% mortality if left untreated) / vaccine available

Brucella

B. suis most common

B. abortus cattle

B. melitensis most invasive

B. canis recent pathogen

GNCB, aerobe, facultative intracellular parasite

use culture (takes forever) since serology is problematic (replicates within macrophages)

animals / infected cheese or milk / inhalation

Transmission: penetrates skin or mucous membrane to reach RE system

Presentation: fever, symmetric lymphadenopathy, joint swelling, hepatosplenomegaly

Primary Diseases: bone marrow (sacroiliitis), liver, kidney, endocardium, brain (see below)

Labs: leukopenia

Complications:

Neuro (2-5%): meningitis, vasculitis, parenchymal CNS lesions, and diseases of the roots and peripheral nerves

Course: longer incubation (7-21 days) / acute (like typhoid) / localized (more in females) / chronic / may relapse

Treatment: tetracycline/streptomycin or doxycycline/rifampin (only 2% mortality untreated, high morbidity) / strain 19 (avirulent) vaccine used for cattle and workers

Neurobrucellosis

culture of tissue with CO2 incubation or serology, CSF analysis

Treatment: doxycycline, rifampin, and possibly bactrim for 2 to 4 months +/ corticosteroids

Yersinia

GNR, aerobe, facultative intracellular

Yersinia pestis (Plague)

bubonic plague from fleas / pneumonic plague from droplet spread (or from bubo)

Transmission: sylvatic cycle: rodent to rodent via flea (endemic) / urban cycle: rat to rat via flea (epidemic)

Course: spreads rapidly, systemically ill with tender lymphadenopathy

YOP proteins made in host cells: H (tyr phosphatase), E (cytotoxic), M (prevents coagulation)

Diagnosis: gram smear from bubo, blood, sputum / culture on MacConkey / direct IF

Treatment: streptomycin (tetracycline for prophylaxis) / chloramphenicol, sulfonamides / killed vaccine available

Yersinia pseudotuberculosis

acute mesenteric lymphadenitis (usually self-limiting) / fever, abdominal pain mimics appendicitis / causes pseudoTB in lymph nodes, spleen, liver (uncommonly causes bacteremia)

Treatment: ampicillin, cephalosporins, aminoglycosides, tetracyclines, chloramphenicol

Yersinia enterocolitica

invasin, ST-like, AIL (complement resistance), various YOPs, 03 and 09 serotypes

fecal oral transmission

Diseases: enterocolitis and/or terminal ileitis (fever, diarrhea, abdominal pain)

Course: more mild in children than adults

uncomplicated enteritis (65%), complicated (15%), appendicular syndrome (10%), ileitis (3%), colitis (5%)

Complications: lymphadenitis (pseudoappendicitis), reactive arthritis (HLA B27), septicemia, erythema nodosum (25%)

Diagnosis: positive stool culture (80%)

Treatment: quinolones, TMP/SMX, AG (streptomycin), chloramphenicol, tetracycline, resistant to penicillins and cephalosporins

Pasteurella multocida

GNCB / animal bites (80% of cat bites) / cellulitis

Rarely occurs without bites / ~10% of patients hospitalized for animal bites

Can lead to sepsis (but not as fast as DF2)

Treatment: ?

Capnocytophaga canimorsus (DF2)

GNR (fastidious, slow-growing) / from dog or cat bites/scratches (and others)

Complications: overwhelming sepsis in asplenic and otherwise immunocompromised, hemolytic anemia (HUS)

Treatment: penicillin

Rickettsia (all arthropod vectors except Coxiella)

small GNCB, aerobic, obligate intracellular parasite

replicate in cytoplasm (Rickettsia) or vacuoles (Coxiella and Ehrlichia)

penetration, incubation, dissemination (rash from vascular effects)

Clinical: patients will exhibit systemic symptoms, thrombocytosis is almost mandatory

Labs: Weil-Felix rxn (proteus agglutination; can be used as screening test) / specific IF (culture dangerous/difficult)

Treatment: tetracycline or chloramphenicol

Louse-borne typhus: human reservoir // all others: humans are accidental hosts

R. rickettsii	large ticks (usu. dog tick and wood tick)	Rocky Mountain Spotted Fever (see below)
R. akari	mites / mouse	rickettsialpox (mild febrile illness)
R. prowazekii	human louse	epidemic typhus (Brill-Zinsser is recrudescent disease-usually effects elderly)
R. typhi	Fleas	endemic / murine typhus (milder typhus)
R. tsutsugamushi	Mites	scrub typhus

Rocky Mountain Spotted Fever or RMSF

South-Central-mid-Atlantic / spring and summer (April to Sept. 95%)

Course:

· 2 to 14 (avg. 7) days: fever, severe frontal headache, fatigue, myalgia, nausea, vomiting, abdominal pain, anorexia

· macular or petechial rash (~85%) of palms and soles rash (similar to syphilis, coxsackie) // centripetal spread (limbs à trunk) [pic] [pic][pic][pic]

· CNS: marked mental changes, meningismus, ataxia, seizures, hallucinations, focal cerebral deficits, and variable PNS involvement / 25% with encephalitis (delirium, stupor, coma)

Diagnosis: serology and antiendothelial antibody studies that take 1 to 2 weeks to reach detectable levels, immunohistologic, PCR of skin lesion biopsies

Labs: reduced WBC’s (increased bands), anemia, thrombocytopenia, hyponatremia, increased AST/ALT

· CSF à mononuclear pleocytosis, increased protein, glial nodules (enlarged endothelial cells, lymphocytes, macrophages containing organisms by IF) , direct effects and immunologic injury (including antiendothelial antibodies)

Prognosis: rapidly progressive, 20% mortality untreated (5% overall)

Treatment: doxycycline and others

Ehrlichia chaffeensis

deer tick / monocytic or granulocytic ehrlichiosis (different organisms)

Presentation: fever, headache, usually no rash

Labs: causes low WBCs, but thrombocytosis is almost mandatory (one text said

thrombocytopenia? I think that was an error?)

Bartonella (Rochalimaea) facultative intracellular parasite

B. henselae

flea bite

Diseases:

· cat scratch disease / systemic symptoms and tender regional lymphadenopathy can be debilitating

· peliosis hepatitis

· relapsing fever

· bacillary angiomatosis (purple, vascular appearing lesions on extremities [pic][pic]; more common, but not always in AIDS)

o biopsy to differentiate from Kaposi’s sarcoma (requires Warthin-Starry silver stains)

· CNS (< 10%): encephalopathy, neuroretinitis (Parinaud’s oculoglandular disease is rare), cerebral arteritis (rare)

Diagnosis: serology (method of choice), culture (1-4 wks), PCR (may not yet be available),

Course: may take 2-4 months to resolve

Treatment: optimum antibiotics unclear but current thinking is 5 days azithromycin +/- aminoglycosides for severe disease / other possible options (doxycycline, macrolides, bactrim or rifampin)

B. quintana

human louse / trench fever / can also cause angiomatosis (but not liver disease) and frequently boney invasion

Treatment: similar to B. henselae (oral if mild, IV if systemic/severe disease)

B. bacilliformis (Peru)

Carrion disease (named for medical student who lost his life researching it)

· acute - Oroya fever / malaise, headache, muscle pains, remittent fever/chills, rapidly developing anemia (extravascular)

· chronic (eruptive) - verruca peruviana or veruga peruana / benign condition characterized by wart like lesions of the skin and no hematologic manifestations

Coxiella burnetii (Q Fever)

facultative intracellular parasite / animals / inhalation, ingestion

Diseases:

· Q fever / incubation 9 to 28 days, high fever, headache, myalgia, atypical pneumonia, hepatitis, rash? (conflicting accounts)

· chronic hepatitis (occurs in ⅓)

· endocarditis [NEJM] (may occur 1 to 20 yrs after exposure)

Weil-Felix reaction

Diagnosis: can test for antibodies to Coxiella (cross-react with Bartonella ones) / clinical diagnosis / tissue pathology (vacuolated histiocytes)

Mycoplasma

- no cell wall (no penicillin sensitivity) / only bacteria with cholesterol

- Eaton’s agar, smallest free living bacteria / found in respiratory/UG secretions

Mycoplasma pneumoniae

no cell wall / strict aerobe / adherence P1 / slower than S. pneumo

Common diseases: tracheobronchitis, pharyngitis, non-purulent otitis media

Uncommon diseases: carditis, meningitis, encephalitis

Epidemiology: 20% community acquired pneumonia (i.e. military, prisons) / 33% of teenage pneumonia / peak age 5-20 yrs and elderly

Transmission: usually close contacts, epidemics every 4-6 yrs in temperate climates

Clinical: most cases do not require hospitalization / immunity is incomplete, reinfection is common

Course: incubation 2-21 days à 2-4 days low-grade fever, headache, sore throat, malaise, dry cough (may be purulent, blood-tinged) à 1-2 days cough worsens for 1-2 weeks then gradual recovery; some will persist with malaise-type symptoms for weeks; others will develop severe illness with pneumonia +/- various systemic manifestations

· Tracheobronchitis or pneumonia (5-10%) / productive cough (yellow +/- blood tinged) / pleural effusion (5-20%) / pleuritis usually minimal / rarely causes chills (like S. pneumo) or nausea, vomiting, myalgias (like influenza) or diarrhea (like adenovirus)

· Pharyngitis: usually with minimal LAD

· non-purulent otitis media or bullous myringitis (15%)

· Skin: younger, males at more risk for erythema multiforme major or Steven’s Johnson Syndrome (up to 7%) involving GI, GU, joints

· Joint: polyarthralgia (can be mono, frank arthritis is rare) / mysositis

· Vascular: Raynaud’s and other vascular occlusive occurrences

· Cardiac: very common (↑10%) complication à chest pain, CHF, conduction defects

· Neuro: uncommon (1 in 100; ~7%, children/young adults, 3-30 days +/- after pneumonia resolves) // various syndromes (e.g. peripheral neuropathy, meningitis, meningoencephalitis, transverse myelitis, hemiplegia, cerebellar ataxia, acute polyradiculoneuritis, cranial nerve palsy, vasculitis of small arteries, veins, capillaries

CXR: unilateral or patchy, usu. lower lobe, sometimes bilateral, pleural effusions (25%)

Labs:

· WBC count usually only mildly elevated

· IgM and IgG specific immunoassay (4-fould rise in serum antibody or single high IgM) // single high IgG titer not useful because titers can remain elevated for a year or more

· cold hemagglutinins (by 7-10 days, peak 2-3 weeks, duration 2-3 months)

sub-clinical hemolysis (RBC I antigen) is the norm / 1:32 is highly suggestive (1:64 is positive), or a 4-fold rise over time) / severe cases 1:20,000 titer (associated with Raynaud’s) / test not very specific, also reacts with EBV (anti-I), CMV (anti-I), adenovirus et al, lymphoma

· complement fixation (levels peak 2-3 weeks, duration 2-3 months)

assay is more specific

· cultures take 7-10 days (gram stain not helpful)

· elevated CK (myositis)

· RBC clumping can cause false positive MCV elevation (with high RDW)

Transmission: prolonged shedding (2-8 days before symptoms and up to 14 weeks after), droplet spread, low infective dose

Immunology: asplenism increases risk of severe infection, complement fixing antibody titres peak 2-4 weeks, last 6 to 12 months, 66% of symptomatic patients develop IgM that cross reacts with I antigen of human red blood cells (can produce hemolytic anemia), other non-specific immune reactions occur

Treatment: azithromycin, clarithromycin >> quinolones > doxycycline / treatment hastens recovery but pts continue to shed infective organisms for weeks

M. hominis

Facultative anaerobe, many serotypes, common GU flora

Diseases: post-partum fever (isolated from 10% of cases), usually self-limiting

Complications: PID, pyelonephritis

Treatment: same as above (but will be resistant to erythromycin)

U. urealyticum

Facultative anaerobe / GU flora in 80% of sexually active people

Diseases: pneumonia (neonates), chorioamnionitis, post-partum fever, non-GC non-chlamydia urethritis

Treatment: tetracyclines (cross-cover chlamydia) / spectinomycin or quinolones for tetracycline resistance

Spirochetes (Treponema and Borrelia)

periplasmic flagella / only by darkfield microscopy, silver impregnation, IF

obligate parasite of humans / non-pathogenic strains found to inhabit oral/anal

T. Syphilis

Primary: 2-4 wks incubation (extreme range of 10-90 days), then painless chancre (days to weeks, one week with therapy; can be located anywhere at primary site of inoculation); ⅓ will have negative serology at this stage

Secondary (weeks to months) [dermis]

· classic lesions involving palms and soles (maculopapular squamous eruption, scattered reddish-brown lesions, thin scale; can mimic almost all dermatological conditions) [pic][pic] / Ddx: atypical pityriasis rosea or erythema multiforme

· may get meningovascular syphilis

· fever, soar throat, mucosal ulcerations, malaise, generalized lymphadenopathy, patchy alopecia, thinning of lateral third of eyebrow

· obliterative endarteritis (involvement of vasa vasorum leads to saccular aneurismal dilatation of aorta; aortic insufficiency)

· condyloma lata (perianal wart like lesions, more stuck-on, full of organisms, will regress)

· Other: arthritis, hepatitis, glomerulonephritis

Latent (early latent < 1 yr, late latent > 1 yr)

asymptomatic (persists in ⅓ of patients) ⅓ of them will heal without treatment

Tertiary or late - years later: may have severe sequelae / damage is autoimmune

Neurosyphilis (8-40% if untreated; > 40% with HIV) can occur during any stage

can present like Pick’s disease (loss of judgment, insight, memory, delusions, hallucinations, changes in personality) / demyelination of posterior column (wide gait, foot slap, paresthesias, incontinence, loss of position/vibratory, impotence) and dorsal root ganglia causes paresis and tabes dorsalis (involves more organisms), Charcot’s joints, Argyll-Robinson pupil (accommodates but doesn’t react to light?), “gun-barrel” site (loss of optic nerve) / CN VII-VIII most commonly (vertigo, tinnitus, loss of facial expression)

o can use LP (but negative VDRL)

Gummatous (9-16% untreated) – mega-immune response to only a few organisms

Congenital syphilis:

100% preventable with screening and treatment / primary/secondary, early latent:

50% vertical transmission rate / late latent, tertiary: 25% vertical transmission rate /

nephrotic syndrome, fibrosis (pancreatitis, GI inflammation, interstitial pneumonia), excess extramedullary hematopoeisis, osteochondritis (undulating growth plate), hepatomegaly, splenomegaly, mucocutaneous lesions, jaundice, lymphadenopathy, “snuffles”/ early: Parrot’s pseudoparalysis / 8-15 yrs develop Clutton’s joints / Hutchinson triad (Hutchinson teeth or blunted upper incisors, interstitial keratitis, 8^th nerve deafness)

Screening: seroconversion occurs from 1-4 weeks after primary chancre

Non-treponemal: Ab to cardiolipin (VDRL), RPR (1:2 low, 1:16 moderate, 1:64 high)

· false positives: EBV, HBV, leprosy, lyme disease, endocarditis (RF), connective tissue disease (RA, SLE, APA), drugs

Treponemal: FTA-ABS or TPI (test directly for organism) / MHA-TP (false positive mainly with lyme disease, remains positive for life)

CSF Studies:

· CSF VDRL (only 60% sensitive, then look at protein/WBCs) [preferred]

· CSF FTAB (too sensitive, ↑ false positives, even from serum contamination of LP)

· MHA-TP (supposedly very high negative predictive value for neurosyphilis)

Screen for other sexually transmitted disease: gonorrhea, chlamydia, HBV, HCV

Treatment:

· Benzathine penicillin G recommended when CNS infection is ruled out / treatment may cause Jarisch-Herxheimer reaction (fever, chills, hypotension occurs within 1-2 hrs; resolves 24-48 hrs; usu. only requires NSAIDs and Tylenol; also occurs with treatment of rat bite fever, leptospirosis, ehrlichiosis) / titre should fall 4 fold within 3 months (negative or near-negative titre at one year) with successful treatment

Primary: penicillin G 2.4 mu IM x 1 [usually given ½ dose in each hip]

Secondary:

Latent (early): penicillin G 2.4 mu IM x 1

Latent (late): penicillin G 2.4 mu IM plus 2.4 mu IM once a week x 3 weeks

Tertiary: high-dose IV penicillin G x 2 wks in hospital (watch for inflammatory response to therapy?) then give one more shot

Alternatives: ceftriaxone or doxycycline 100 mg bid 2 wks or tetracycline 500 mg qid 2 wks or erythromycin mg qid 2 wks

VDRL on LP in patients with CNS signs, HIV or immunocompromised

In HIV patients, recheck titres q 6 months (to 18 months) (consider re-treatment if )

Treponema pallidum (relatively anaerobic)

-T. p. pallidum syphilis (microaerophilic)

-T. p. pertenue yaws (tropical Africa and Asia)

-T. p. endimicum endemic syphilis (now rare)

-T. carateum pinta (skin lesions) (L. America)

-T. vincentii Vincent’s disease or “trenchmouth”

Borrelia

visible by LM with Giemsa or Wright stain (because it’s larger)

arthropod vector (most common in U.S.)

VMP variable major proteins result in relapses / expression plasmid and storage plasmid (EPSP)

B. burgdorferi or Lyme disease

Deer tick (hard body, Ixodid or Ixodes tick; NE (Maine to Maryland), Midwest (Wisconsin to Minnesota), NW (northern California and Oregon) / 90% of vector-borne infections

Course: some say < 10% of inoculations become infected / 10-20% of infections are asymptomatic

Unusual syndromes: CNS vasculitis/infarction, increased ICP, psychiatric disease, myositis

Co-infection: 10% with either babesiosis (splenectomized) or ehrlichiosis (elderly)

Stage One

erythema migrans or erythema chronicum migrans (expanding red rash, central clearing; 20-30cm) occurs 3-32 days after bite / secondary rings may occur within original circle / may itch or burn and may see systemic symptoms during this phase (see below) /no rash noticed in 20%

Stage Two (< 1 months)

Skin: malar rash, conjunctivitis, or, rarely, diffuse urticaria / EM and secondary lesions (similar to primary, but smaller) usually fade within 3 to 4 weeks (range, 1 day to 14 months)

Heart Block: 8% get various degrees of heart block (usu. resolve within a week) / usu. don’t really get much myocardial damage, but can get mild pericarditis with non-specific EKG changes / cardiac involvement usu. from 3 days to several weeks

Systemic: malaise and fatigue, headache, fever and chills, generalized aches, and regional lymphadenopathy

CNS/PNS (15% untreated): meningitis, encephalitis, encephalomyelitis, cranial nerve palsy (especially II and VII, Bell’s Palsy), acute painful radiculoneuritis, chronic polyradiculoneuropathy mononeuritis multiplex

Musculoskeletal: pain in joints, tendons, bursae, muscle, or bones, often without joint swelling / migratory polyarthritis (hours to days per location; most common in knees; may last months)

Eye: conjunctivitis >> retinal problems, other

Stage Three

migratory polyarthritis

can last several years / 500-100K WBC, no positive Cx, but DNA is there / HLA-DRB1*0401

neuro: psychological problems, peripheral neuropathies, encephalomyelitis (more in Europeans)

skin: acrodermatitis chronica atrophicans (more in Europeans)

autoimmune response similar to syphilis

Diagnosis: clinical diagnosis (30-40% will be seronegative at presentation; 60% seroconversion by 2-4 wks, 90% by 4-6 wks, then usually positive for several years) / sensitivity for PCR in synovial fluid ~85%, lower in CSF

Labs (stage two): positive MHATP, high ESR, elevated IgM, elevated ALT, GGT, LDH, mild anemia

CSF: normal glucose, elevated protein, lymphocytic pleocytosis ~100,

Treatment:

Stage I/II: 20-30 days doxycycline or amoxicillin or cefuroxime or ceftriaxone / macrolides 2^nd choice / IV ceftriaxone with heart block, and possibly steroids if not better < 24 hrs / 15% have Jarisch-Herxheimer-like within 1^st 24 hrs of treatment

Late: IV ceftriaxone / IV penicillin

Treatment failure is rare and recurrence of non-specific symptoms may not be due to ongoing infection

B. recurrentis

Tick (endemic) or louseborne (epidemic) relapsing fever / antigenic variation causes reemergence

Presentation:

· CNS (10%): hemorrhage, perivascular infiltrates, degenerative lesions

· CNS (2% to 5%): meningitis, vasculitis, parenchymal lesions, nerve roots and PNS

· Secondary vasculitis with mycotic aneurysm formation, subarachnoid/intraparenchymal bleeding

Diagnosis: microscopic detection in peripheral blood during a febrile episode / serology is supportive

Treatment: tetracyclines, chloramphenicol, penicillins, erythromycin

B. hermsi

tickborne relapsing fever

Leptospira interrogans

animals / contaminated urine (rodent urine), water

Diagnosis: culture urine / blood / CSF

Biphasic illness

Primary

Secondary (immune phase) / late uveitis

Treatment: tetracycline or penicillin (early ~)

Weil’s syndrome (severe) (5 to 10%)

more severe icteric form of Leptospirosis / significant hepatic and renal involvement Incubation: 7 to 12 days

Presentation: biphasic illness, fever, severe HA, myalgia, conjunctival injection, spontaneous defervescence after several days

· first phase: blood and CSF cultures positive

· second phase: immune response, days later, meningitis in 70-90% (can be subclinical)

note: uveitis often occurs months to years into the infection / ~7% show additional neurologic syndromes

· CNS: subarachnoid, parenchymal, subdural, spinal hemorrhage, can have vasculitis with widespread capillaritis and multiple vessel occlusions

· bleeding worsened by thrombocytopenia, coagulopathy, and renal disease

Diagnosis: culture or IF staining of blood/CSF/tissue

Treatment: tetracycline or B-lactams

Spirillum minor

rat bite fever (also caused by Streptobacillus monoformis)

Other Bacteria

Fungi

Superficial

Non-Tinea Tinea

Tinea versicolor (Malassezia furfur) [dermis]

Appearance: hypopigmented or hyperpigmented, oval, scaling or non-scaling, coalescent macules on trunk and proximal extremities / lesions can be inflammatory and/or vesicular and mimic other infectious processes

Diagnosis: KOH prep / green fluorescence on Wood’s light (routine fungal cultures will not grow; also may have false negative if patient recently showered)

Pathology: KOH reveals ‘spaghetti and meatballs’ (short hyphae and yeast forms)

Tinea nigra Exophialia werneckii

Black piedra Piedriae hortae

White piedra Trichosporon beigelii

Dermatophytes (Tinea sp.)

Dermatophyte test media - they will turn red / others yellow

Treatment: griseofulvin, some people use fluconazole/itraconazole instead (2 week therapy)

Epidermophyton macroconidia (smooth)

Microsporum macroconidia (rough)

Trichophyton microconidia

Tinea capitis

Treatment: requires oral griseofulvin or itraconazole or terbinafine

Endothrix

T. tonsurans black dot / may present in 4 different ways / common in Houston

T. violaceum

T. schoenleinii favus

Ectothrix

M. audouinii epidemic tinea

M. canis zoophilic

T. mentagrophytes zoophilic

Tinea barbae

T. verrucosum cattle

T. mentagrophytes zoophilic

Tinea unguinum

Note: use itraconazole

Kerion

Trychophyton spp.

Tinea corporis [dermis]

Treatment: topical antifungal

Erythematous scaly plaque with central clearing and serpiginous border

Transmission: infected animal or person-to-person

M. canis, rubrum, mentagrophytes, concentricum

Tinea cruris

E. floccosum, T. rubrum

the groin and beyond

Tinea pedis [dermis]

T. rubrum

classic pattern of (2 hands + 1 foot) or (2 feet + one hand) / often resistant to treatment

T. mentagrophytes

Sub-Cutaneous

Sporothrix shenckii (sporotrichosis)

lymphocutaneous, pulmonary / Central/South America, Mexico / worse with alcoholics,

immunocompromised

Micro: dimorphic / rosette conidia / asteroid bodies / unequal budding

Treatment: KI therapy

Chromomycosis

painless / cauliflower-like / black fungi / sclerotic bodies

Mycetomas

Madura foot / sulfur granules / lollipop conidia

Diagnosis: histological exam distinguishes (broad, eumycetoma elements) vs. (narrow, actinomycete elements) / geography and culture for confirmation / serology not used

Complications: can cause substantial regional destruction (along fascial planes), but distant spread is uncommon / may require amputation of extremities

Eumycetoma

slower progression / usually starts hurting when bone becomes involved

Treatment: may respond to some antifungal therapy, but without complete surgical debridement, relapse is almost certain

Pseudallescheria boydii – most common in US, Canada

Madurella mycetomatis

Actinomycetoma

faster progression / lesions may spread

Treatment: bactrim + (streptomycin or rifampin) / dapsone + streptomycin / alternative à augmentin / 9 months of treatment

N. brasiliensis, Actinomadura madurae

most common in S. and Central America, Caribbean

lumpy jaw sulfur draining tracts

pulmonary nocardiosis (WAF)AIDS / may disseminate

cutaneous nocardiosis (WAF) soil in you

Systemic

Coccidioides immitis (San Joaquin Valley Fever) [MRI]

barrel arthroconidia (inhaled) / spherule ruptures (~yeast) / erythema

Southwest US, Mexico, Columbia, Paraguay, Venezuela (not Brazil)

Risk factors: archaeological excavation, rock hunting/climbing, military maneuvers, construction work

Presentation:

40% symptomatic

(60% asymptomatic!)

can cause thin walled, pyogenic granuloma, may cause pleural effusion +/- hemoptysis

Other: hypersensitivity reaction, erythema nodosum, erythema multiforme, arthritis, conjunctivitis

5% pulmonary residual

1% disseminated

⅓ get meningitis (see below)

Filipino men are uniquely susceptible

Diagnosis: eosinophilia / CSF culture (50%), sputum culture (must warn lab; biohazard), specific antibodies helpful (may take 8 weeks to be formed)

· CXR findings same as chronic cavitary Tb (small, irregular, single or multiple cavities, upper lobes)