P2 Microbio Bugs

All bugs (no meds)

Staphylococcus Aureus

• gram+ (violet stain), clustered cocci, catalase+, small yellow on blood agar, coagulate+, b-hemolytic

• ferrments mannitol on salt agar

• in nasal flora and on skin

• transmitted via hands, sneezing, surgical wounds, contaminated foods

• predisposing factors: surgery/wounds (severe leukopenia), IV drug abuse, chronic granulomatous disease, cystic fibrosis

• D: gastroenteritis- rapid onset after contaminated foods, enterotoxins A-E (heat-stable toxins). Tx self limiting

• D: acute infective endocarditis- usually r heart tricuspid infection, fibrin platelet mesh, cytolytic tox (PVL)

• D: TSS- fever, hypotension, scarlatiniform rash, multi-organ failure, from TSST-1 (super antigen toxin causing cytokine storm)

• D: osteomyelitis- fever, bone pain, lytic bone lesions, from coagulase+ and cytolysin tox

• D: pneumonia (not leading cause)- post-viral infection, patchy infiltrates, rapid onset productive pneumonia, high fatality and necrosis rate, salmon colored sputum, from coagulase+ and cytolysin tox

• D: abscesses and mastitis- subQ tenderness, hot, swelling, from coagulase+ and cytolysin tox

• D: impetigo, scalded skin syndrome- red papules to bullae, skin peeling, from coagulase and exfoliatins

• D: surgical infections from wound peeling- fever with cellulitis and/or abscesses, from TSST, coagulase, exfoliatins

• Tx: MSSA- nafcillin/oxacillin; MRSA(altered PBP)- vancomycin; VRSA/VISA- quinupristin/dalfopristin

Staphylococcus Epidermis

• gram+ (violet stain), catalase+, coagulase-, gamma (no) hemolysis

• novobiocin sensitive, biofilm producer

• on normal skin flora, can contaminate blood cultures

• D: endocarditis of artificial heart valves in IV drug users, catheter infection, prosthetic device infection

• Tx: vancomycin

Staphylococcus Saprophyticus

• gram+ (violet stain), catalase+, coagulase-, gamma (no) hemolysis

• novobiocin resistant

• D: UTI in newly sexually active females

• Tx: nitrofurantoin

Streptococcus Pyogenes (Group A)

• gram+ cocci in chains, catalase-, b-hemolytic, hyaluronic acid capsule, bacitracin sensitive, PYR+

• human throat and skin reservoir

• transmission thru droplets or direct contact

• pathox:

Strep Agalactiae