Denise - Anaerobes (Bacteroides) Flashcards
What are Bacteroides
Anaerobic Gram Negative Rods
Where are anaerobic GNBs normally found
Oral cavity
Female genital tract
Gastrointestinal tract
Write about bacteroides infection
Predominant anerobes in human flora
Cause infection when they gain access to tissues or blood during bowel perforation (surgery or trauma)
Endogenous
Polysaccharide capsule NB in pathogenesis
Associated with polymicrobial abscesses
Antimicrobial resistance is common
Treated with metranidazole
Write about the importance of bacteroides infection
Most common anaerobe isolated in the lab
Antimicrobial resistance is common
Treated with metranidazole
Write about the virulence of bacteroides
(3)
Surface structure variation
Polysaccharides, fimbriae, enterotoxin
Enzymes
Enterotoxin
What enzymes act as virulence factors in Bacteroides
Hyaluronidase
Chrondroitin
Sulphatase
DNase
Lipase
Protease
Neuraminidase
What samples are seen in the lab
Pus
Tissue samples
Drainage of abscesses
Biopsy
What is done on day 1 investigation
Blood agar plus neomycin/metranidazole disc
Incubated anaerobically
How do you incubate anaerobically
Used in closed environmental chambers to rapidly generate anaerobic atmospheres
An oxygen depleted environment essential for obligate anaerobic microorganisms
What are the basic characteristics of the bacteroides species
GNBs (slender)
Catalase positive
What identification tests are needed for bacteroides
MID8
MALDI
Bile susceptibility testing
Are the bacteroides susceptible to bile
No they are resistant (live in the gut)
What antimicrobials are bacteroides susceptible to
Rifampicin and Erythromycin
What antimicrobials make up the MID8 test
Erythromycin
Rifampicin
Collistin sulphate
Penicillin
Kanamycin
Vancomycin
What are the MID8 Mastring results for bacteroides fragillis
E = susceptible
RP = susceptible
CO = resistant
Penicillin = resistant
K = resistant
Va = resistant
