gram positive cocci - bacteriology exam 1

gram positive cocci genus

staphylococcus, streptococcus, enterococcus

epidemiology of staph

normal flora

transmission of staph

person to person, fomites

often observed with staph

disruption of normal flora, insertion of foreign bodies

gene regulation

not all genes are expressed at same time, environment matters

staph likes to acquire dna…

to help it gain antibiotic resistance

virulence factors of staph

capsules, adhesions, biofilms, toxins (cytotoxins, enterotoxins, super antigens)

capsules

sugar cell on outside of surface. makes it difficult to phagocytize

adhesions

make phagocytic cells to take it up, allows bacteria to stay inside cell

cytotoxins

cause destruction of cells and shrinkage, creating gaps for things to pass through

infections from staph

bullous impetigo, scalded skin syndrome, bacteremia

treatment of staph

resistant to antibiotics (MRSA)

prevention of staph

clean sterilize medical equipment, minimize exposure

genus of strep

strep a (s. pyogenes), strep b (s. agalactiae), s. pneumonia

virulence factors of strep a

immune avoidance (capsule, m proteins, c5a peptidase), M and F proteins, exotoxins, enterotoxins, superantigens

m proteins

block c3b from binding, preventing opsonization from occuring

c5a peptidase

blocks inflammation

treatment of strep

antibiotics

pathogenesis of strep b

newborns - bacteremia, pneumonia, meningitis

bacteremia

bacteria gets into blood which circulates throughout body

treament of strep b

treat pregnant women

epidemiology of enterococcus

normal flora of GI tract

transmission of enterococcus

person to person, fomite, fecal-oral

virulence factors of enterococcus

wide growth range (aerobic and anaerobic, high salt, broad ph), biofilm formation, antibiotic resistance