Bacterial Skin Infections II Flashcards
Clostridium perfringens General
-Gram (+) bacilli, Anaerobic, Spore forming, non‐Fasciitis
Clostridium perfringens Pathogenesis
TOXIN production:exotoxin (alpha, phospholipase, hemolysins, collagenase), NECROSIS -fascitis, gas gangrene
Cutaneous Anthrax general
Black eschar within 12‐36 hours – No pus – painless • Generalized toxic effects – as bacilli spread to lymphatics – septicemia • Edema
Bacillus anthracis General
– Gram (+), spore forming, encapsulated rods – found in soil, water, air & vegetation -Bioterorism
Bacillus anthracis Pathogenesis/Virulence factors
-polyglutamic acid capsule –exotoxin components that enter the cell: protective Ag (PA), 2 NZ components (edema factor (adenylate cyclase) and lethal factor (endoprotease/MAPKK)
Enterococcus faecalis General
-catalase negative,lancet or bullet shaped, survive high salt and bile concentrations
Enterococcus faecalis Sources/Transmission
Catheter, normal flora, person to person via fecal oral route
Enterococcus faecalis Virulence
-resistant to Optochin (P disk). -MANY ways to be antibiotic resistant
Enterobacter cloacae General
Gram (‐) motile bacillus, glucose fermenter, lactose fermenter, MacConkey agar -ornithine decarboxylase‐positive, urease negative
Enterobacter cloacae Virulence/Resistance
Enotoxin
Enterobacter cloacae Sources/transmission
-Nosocomial pathogen -Common in pts with recurrent infections, instrumented, anatomical defects
Acinetobacter baumanni General
-pleomorphic aerobic Gram (‐) rod – Gram stain similar to H. influenzae, Strictly aerobic, Nonfermenting, Nonfastidious, Nonmotile, Catalase‐positive, Oxidase‐negative
Acinetobacter baumanni Sources/Transmission/Risk Factors
-nosocomial pathogen,catheter, normal flora, survive on dry inanimate surfaces(1‐5 months) • biofilm on glass or plastic surfaces advanced age • immune suppression, major trauma or burn injuries, invasive procedures • previous administration of antibiotics
Acinetobacter baumanni Virulence
-INHERENT MULTI DRUG RESISTANCE -Fimbriae, LPS, Biofilm Enzymatic (degradation: β‐lactams, cephalosporins, modification and/or efflux),Nonenzymatic (Changes in outer membrane proteins, Multidrug efflux pumps,Alterations in affinity or binding of penicillin‐binding proteins -Endotoxin: targeted (TLR4)
Acinetobacter baumanni Treatment
experimental treatment: LpxC‐1 blocks LPS synthesis & TLR4‐induced inflammatory cytokine cascade is shut down
Acinetobacter baumanni Clinical Manifestations
Pneumonia,meningitis,Peritonitis, SURGICAL SITE INFECTION, SKIN INFECTION
Shewanella sp. General
-unusual cause of disease in humans,emerging infection • often IDed wrong as Pseudomonas • Gram negative bacillus, oxidase+, catalase+, non‐fermenter, H2S+
Shewanella sp. Clinical Manifestations
-soft tissue chronic infections -cellulitis, abscesses, bacteremia, wound or burn infection
Shewanella sp. Source/Risk factors
-ubiquitous: foods, sewage, fresh & salt water -hepatobiliary disease, peripheral vascular disease, poor hygiene, low socioeconomic status
Aspergillus sp. General
-Fungus -hyphae, septae & branch at 45° angles, silver stain
Aspergillus sp. Clinical Manifestations
Endocarditis
Candida albicans General
-Fungus -budding yeast
Candida albicans Source/Transmission
-Nosocomial infection -Catheter, broad spectrum antibiotics -Diabetic, immunosuppressed
Clostridium tetani General
-Gram‐positive rods – Spore‐forming – Strict anaerobes
