Which medium is used to recover Bacteroides species?

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Multiple Choice

Which medium is used to recover Bacteroides species?

Bacteroides species are anaerobic bacteria that need a selective, differential medium to grow from clinical specimens. Bile Esculin Agar (BEA) does just that: the bile inhibits many other flora, and the esculin in the medium is hydrolyzed by Bacteroides (especially B. fragilis group), producing a distinctive dark complex. Incubating in a CO2-rich environment for about 48 hours further supports the growth of these anaerobes. The other media target different organisms—Thayer-Martin for Neisseria, chocolate agar for fastidious respira­tory pathogens, and CNA for Gram-positive cocci—so they’re not optimal for recovering Bacteroides.

Bacteroides species are anaerobic bacteria that need a selective, differential medium to grow from clinical specimens. Bile Esculin Agar (BEA) does just that: the bile inhibits many other flora, and the esculin in the medium is hydrolyzed by Bacteroides (especially B. fragilis group), producing a distinctive dark complex. Incubating in a CO2-rich environment for about 48 hours further supports the growth of these anaerobes. The other media target different organisms—Thayer-Martin for Neisseria, chocolate agar for fastidious respira­tory pathogens, and CNA for Gram-positive cocci—so they’re not optimal for recovering Bacteroides.

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