Question

what is the purpose of Lab: Isolation And Identification Of Staphylococci?

Answer 1

Staphylococci is gram positive cocci in cluster or groups.These are catalase positive and produce catalase enzyme and are facultative anaerobes and they are oxidase negative.Medically important organisms are Staphylococcus aureus,Staphylococcus epidermis,Staphylococcus saprophyticus.Staphylococcus are catalase positive and in gram stain smear they look like clusters and they an be coagulase positive group organisms are S.aureus these are beta hemolytic on blood agar they produce yellow colour colonies and are mannitol positive which distinguishes from S.epidermidis.Non coagulase organisms are S.epidermidis is novobiocin sensitive and are beta or gamma hemolytic and S.saprophyticus is novobiocin resistant and gama hemolytic.Staphylococcus aureus is most opportunistc pathogen and nosocomial and diagnosis of this organism is done by gram staining test,catalase test,coagulase test,yellow colonies on blood agar ,PYR+ and bacitracin resistant.Gram positive cocci identification round shaped are cocci and they can be staphylococcus catalase positive are S.coagulase and coagulase negative are S.epidermis which are novobiocin sensitive and S.saprophyticus which is novobiocin resistant when they are rod shaped they are bacilli,carynebacterium,clostridium,listeria,bacillus.

S.aureus organism is present in normal flora of skin and passages but can cause a wide range of illinesses from minor skin infections to life threatening diseases like pneumonia,osteomyelitis and endocarditis.S.aureus causes skin infection including pimples,impeigo,furuncles,cellulitis.This bacteria causes disease mediated by toxins.Some strains produce the exotoxin TSST 1,which cause toxic shock syndrome and some strains produce enterotoxin which causes food poisoning.S.epdermidis organism can cause infection in pateints with compromised immune system and it is a adharent biofilm that grow on devices.S.saprophyticus is commonly found in urinary tract infections.