TABLE 3.
Summary of identification characteristics and diagnostic test methods available in the United States a
| Organism(s) | Growth characteristics | Key biochemical reactions | Clinical laboratory diagnostic test methods |
Clinical symptoms used for diagnosis | Public health laboratory referral | |||
|---|---|---|---|---|---|---|---|---|
| Culture | Chromogenic agar | Antigen detection | NAAT | |||||
| Aeromonas spp. b | BA, beta-hemolytic | Oxidase positive; TSI, K/A, gas; LIA, K/A or A/A | ✓ | |||||
| Bacillus cereus b | BA, beta-hemolytic | ✓ | Food and stool cultured for outbreak investigations | |||||
| Campylobacter spp. | Campylobacter medium, gray-white colonies | Oxidase positive, catalase positive, sodium hippurate positive for C. jejuni | ✓ | ✓ | ✓ | |||
| Clostridium difficile b | NA | NA | ✓ | ✓ | ||||
| Clostridium perfringens b | NA | NA | ✓ | Food and stool cultured for outbreak investigations | ||||
| Edwardsiella tarda b | Lactose nonfermenter with H2S production on HE, MAC, XLD, SS | TSI, K/A, H2S, ± gas; LIA, K/K or K/NC, H2S | ✓ | |||||
| Escherichia coli O157 | SMAC, sorbitol nonfermenter | TSI, K/A or A/A, gas; LIA, K/A or A/A | ✓ | ✓ | ✓ | |||
| Escherichia coli, STEC | SMAC, sorbitol fermenter (unless O157) | TSI, K/A or A/A, gas; LIA, K/A or A/A | ✓ | ✓ | ✓ | |||
| Listeria monocytogenes b | BA, beta-hemolytic | ✓ | Food and stool cultured for outbreak investigations | |||||
| Salmonella spp. | Lactose nonfermenter with H2S production on HE, MAC, XLD, SS | TSI, K/A, H2S, ± gas; LIA, K/K or A/A or K/NC (rare), H2S | ✓ | ✓ | ✓ | ✓ | ||
| Shigella spp. | Lactose nonfermenter on HE, MAC, XLD, SS | TSI, K/A; LIA, K/A or A/A | ✓ | ✓ | ✓ | |||
| Staphylococcus aureus b | NA | NA | ✓ | Food and stool cultured for outbreak investigations | ||||
| Yersinia enterocolitica b | CIN, pink bull's eye; lactose nonfermenter on MAC; ferments sucrose on HE | TSI, A/A or K/A; LIA, K/A or A/A; urea positive | ✓ | |||||
| Vibrio spp. b | TCBS, sucrose fermentation seen with V. cholerae; no sucrose fermentation for V. parahaemolyticus; V. vulnificus is sucrose fermentation variable | Oxidase positive; TSI, A/A or K/A; LIA, K/A or A/A | ✓ | |||||
a
Abbreviations: BA, blood agar; HE Hektoen enteric agar; MAC, MacConkey agar; XLD, xylose-lysine-deoxycholate agar; SS, salmonella-shigella agar; CIN, cefsulodin-Irgasan-novobiocin agar; TCBS, thiosulfate-citrate-bile salts-sucrose agar; SMAC, MAC with sorbitol; TSI, triple sugar iron agar; LIA, lysine iron agar; A, acid; K, alkaline; NC, no change; NA, not applicable.
b
The organism is not part of the routine stool culture, and culture should be performed only on request.