AIIMS November 2011 – MCQ 174

With reference to Bacteroides fragilis the following statements are true, except:
a) B. fragilis is the most frequent anaerobe isolated from clinical samples.
b) B. fragilis is not uniformly sensitive to metronidazole
c) The lipopolysaccharide formed by B. fragilis is structurally and functionally different from the conventional endotoxin
d) Shock and disseminated intravascular coagulation are common in Bacreriodes bacteremia

(Repeat question – AIIMS Nov 06 – AA q80)

Correct answer : d) Shock and disseminated intravascular coagulation are common in Bacreriodes bacteremia

Bacteroides:
Gram negative anaerobic bacilli
Most common anaerobic pathogen isolated from clinical specimens
Virulence factors include capsular polysaccharides and lipopolysaccharide endotoxin
Lipopolysaccharide endotoxin is much less toxic compared to other gram negative bacteria
Hence infections do not directly produce signs of sepsis, which is common in other gram negative bacteria
Some are resistant to metronidazole