Detection of acid production from carbohydrates by Riemerella anatipestifer and related organisms using the buffered single substrate test.

One hundred and twenty-one Riemerella anatipestifer field strains from wild birds, domesticated poultry and pigs were examined for their ability to produce acid from carbohydrates by using conventional biochemical and buffered single substrate (BSS) test methods. The type strains of the species R. anatipestifer and taxometrically related genera Chryseobacterium and Bergeyella were included in the study. In contrast to 10 indole-positive R. anatipestifer variant strains, only a few of the 111 typical indole-negative R. anatipestifer strains produced acid from dextrin (32%), glucose (17%), maltose (14%) and trehalose (5%) when the conventional test procedure was used. Using the BSS test all the field isolates and the type strain of R. anatipestifer produced acid from one or more carbohydrates, most of them from dextrin (96%), maltose (91%), glucose (87%), mannose (83%), less frequently from fructose (38%) and only in some cases from trehalose (19%). One hundred and six (87%) of the R. anatipestifer strains could be assigned to 8 biovars, based on the diversity of the carbohydrate acidification patterns. The remaining 16 R. anatipestifer isolates gave delayed reactions and displayed 13 different carbohydrate acidification profiles. The Chryseobacterium and Bergeyella type strains also produced acid from more carbohydrates when the BSS test was used. The BSS-carbohydrate acidification pattern of the Chryseobacterium indologenes strain was similar to that of R. anatipestifer biovar 3.