title: Temperature-dependent cultural and biochemical characteristics of rhamnose-positive Yersinia enterocolitica.
abstract: Clinical isolates of rhamnose-positive Yersinia enterocolitica (Y.e.rh+) were compared with typical rhamnose-negative Y. enterocolitica (Y.e.rh-) and with Yersinia pseudotuberculosis. The Y.e.rh+ differed from the Y.e.rh- and Y. pseudotuberculosis in their ability to ferment raffinose and lactose, utilize citrate and in their inability to grow on Hektoen enteric agar at 22 or 37 C, on Salmonella-Shigella agar at 37 C, and scant on xylose-lysine-deoxycholate agar at 37 C. An extensive temperature-dependent profile of characteristics was established for the Y.e.rh+: motility, acetoin production, citrate utilization, growth on Salmonella-Shigella agar, and ampicillin resistance occurred at 22 C but not 37 C; fermentation of melibiose, raffinose, and cellobiose occurred within 24 h at 22 C, but not before 5 days at 37 C; fermentation of rhamnose and production of beta-galactosidase occurred within 24 h at 22 C, but not before 48 h at 37 C; greater resistance to ampicillin, chloramphenicol, streptomycin, kanamycin, carbenicillin, and gentamicin was observed at 22 than 37 C; and good growth on xylose-lysine-deoxycholate agar occurred at 22 but not 37 C. For optimal recovery of Y.e.rh+ from mixed culture, e.g., stools, two MacConkey plates should be inoculated and incubated, one at 37 C, and one at 22 C. Lactose-negative colonies appearing after 48 h on the 22 C MacConkey agar but not the 37 C MacConkey agar should be considered possible Y.e.rh+. Biochemicals should be tested in duplicate, one set incubated at 22 C, one set at 37 C. Antibiotic susceptibility tests of Y.e.rh+ isolates should be incubated at both 37 C and at a lower temperature to allow the greatest expression of resistance of these organisms to the various antibiotics.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002951:Citrates / Q000378:metabolism; D004352:Drug Resistance, Microbial; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D005285:Fermentation; D005696:Galactosidases / Q000096:biosynthesis; D006801:Humans; D007785:Lactose / Q000378:metabolism; D011887:Raffinose / Q000378:metabolism; D013045:Species Specificity; D013696:Temperature; D015007:Yersinia / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D002951:Citrates; D005696:Galactosidases; D007785:Lactose; D011887:Raffinose