An organism occasionally misidentified as an enteric pathogen because it produces a large amount of H2S is

An organism occasionally misidentified as an enteric pathogen because it produces a large amount of H2S is

• A. Burkholderia cepacia
• B. Burkholderia pseudomallei
• C. Pseudomonas putida
• D. Shewanella putrefaciens

Answer: (D)

Producing a lot of hydrogen sulfide can make a non-enteric organism look like an enteric pathogen on sulfur-reducing media, since H2S production is a hallmark some enteric bacteria use (for example, Salmonella). Shewanella putrefaciens is a nonfermentative Gram-negative rod that can generate substantial H2S, so its appearance on tests like a sulfur-reducing medium can mimic enteric H2S producers and lead to misidentification as an enteric pathogen. The other organisms listed do not typically show heavy H2S production in routine testing, making Shewanella putrefaciens the best match for this scenario.

Producing a lot of hydrogen sulfide can make a non-enteric organism look like an enteric pathogen on sulfur-reducing media, since H2S production is a hallmark some enteric bacteria use (for example, Salmonella). Shewanella putrefaciens is a nonfermentative Gram-negative rod that can generate substantial H2S, so its appearance on tests like a sulfur-reducing medium can mimic enteric H2S producers and lead to misidentification as an enteric pathogen. The other organisms listed do not typically show heavy H2S production in routine testing, making Shewanella putrefaciens the best match for this scenario.