Bacteria
Staphylococcus (MRSA), Streptococcus, Pneumococcus, Enterococcus, Corynebacteria
Listeria,
E. rhusiopathae
Bacillus (B. anthracis, B. cereus), N. gonorrhea,
N. meningitis
Anaerobes GPR: Clostridium (C. perfringens, C. botulinum, C. tetani, C. difficile)
Actinomyces, Proprionibacterium, Lactobacillus, Eubacterium
GNR: Bacteroides, Prevotela, Fusobacterium
Other: Veillonella (GNC), Peptostreptococcus (GPC)
Enteric E. Coli,
Shigella, Salmonella, Klebsiella, Vibrio, Campylobacter, H. pylori
Pneumonia GNCB – H. influenza et al, B. pertussis,
Pseudomonas, Legionella
AFB - M. tuberculosis, M. avium, other AFB,
Actinomyces, Nocardia
Zoonotic Francisella, Brucella, Yersinia, Pasteurella, Rickettsia, Coxiella, Ehrlichia, Bartonella, Mycoplasma, Borrelia, Leptospira
STD Syphilis,
Chlamydia, Mycoplasma, HSV
Superficial T. versicolor,
dermatophytes
Systemic coccidioides,
histoplasma, blastomyces, paracoccidioides
Opportunistic Candida, Cryptococcus,
Aspergillus,
Zygomycetes,
PCP
Respiratory RSV,
influenza, parainfluenza, rhinovirus, coronavirus, adenovirus
Childhood Exanthems
measles, mumps, rubella, roseola, chicken
pox
Zoonotic EEE, WEE,
hemorrhagic fevers, rabies
Protozoa Giardia, Isospora,
Cryptosporidium, Toxoplasma,
Plasmodium (malaria), Trichomonas
Nematodes Ascaris, Strongyloides, CLM,
VLM, Echinococcus
Tapeworms:
Beef, Pork, Fish, Dog
Trematodes Schistosomiasis
·
Case Presentations from Johns
Treatment: nafcillin/oxacillin,
amp/sul, vancomycin, doxycycline, clindamycin, fluoroquinolones, cephalosporins
(more 1st), bactrim
Labs: B-hemolysis, catalase + /
hemolysin, coagulase / protein A (binds Fc-Ig, hinders C3b opsonization)
Diseases:
Abscesses
Stop
reading this and go drain that M-F / can cause hot or cold
(indolent) abscesses
Impetigo [pic]
Scalded skin (Ritter’s) [pic]
[pic]
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
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)
catalase +
protective slime / adherent
slime / line or device related
S.
saprophyticus
catalase +
UTI in young women / more
resistant
S. hemolyticus
more resistant
GP diplococci
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)
CAMP +, B-hemolysis
mother to child via vaginal delivery / pneumonia,
neonatal bacteremia, meningitis (esp. neonates), UTI
Treatment: ampicillin
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