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what are some species in entrobacteriea group?
what does term Enteric mean?
Relating to intestine
what are some general characterestics associated with Entrobactereae?
- gram negative
- fimbrease and sex pili
- might be motile (pertrichous flagella)
- may have capsule
what are some physiological factors associated with Entrobactereae?
- ferments glucose
- reduce nitrate
- oxidase negative
- catalase positive
- facultative anaerobe
what are some colony morphology associated with Entrobactereae?
- the are moist gray smooth colonies on non.selective media ( blood agar)
- special media is used for separation of genera and species
what is features of McConley agar allowing it to be used for culturing Entrobacterea species?
- Crystal violet inhibits Gram positive
- it allows for differentiation between lactose fermentors ( e.coli and Klebsiella) presence of pink colonies Vs. non.fermentors ( shigella, salmonella)
how many antigenic structures are present in Entrobacterea?
- K/Vi ( capsule)
- H ( flagellar)
- O ( somatic ))
- Lps ( antigen)
what is flagella?
- multiple flagelin subunits anchored in bacterial cell wall
- 20 micro m long
- important for motility
- binds to epithelia cell
what is fimbrea?
- helically arranged identical subunits ( some carry adhesins)
- length .5-10 micro m
- not for motility
- binds to epithelial cells of intestine and respiratory tract.
what is TTSS?
- it is a factor that all pathogen in Entrobacteriae group rely on for virulance
- it is a multi protein complex
- only expressed only after infection of host
- syringe like
- used to inject virulance factor into host cell
Somatic (o) antigen structure includes:
- Core polysacharide
- O specific oligosacharide
- Lipid A ( endotoxin, Part causing toxic shock)