Frequency of isolation of Porphyromonas species from infected dog and cat bite wounds in humans and their characterization by biochemical tests and arbitrarily primed-polymerase chain reaction fingerprinting

We isolated 40 strains of Porphyromonas (formerly Bacteroides) species from 29 of 102 cat and dog bite wounds in humans. P. salivosa, P.gingivalis, and P.canoris were the most frequent isolates. A comparison of the RapID ANA II system (Innovative Diagnostic Systems, Norcross, GA), An-IDENT panels (bioMerieux, St. Louis), and APIZYM strips (bioMerieux) showed that the latter kit best characterized these isolates because it included tests for trypsin and chymotrypsin activity; however, the tests for glycosidase activity in this kit were less sensitive than were those in the other kits. None of the biochemical systems was able to identify all species. Arbitrarily primed-polymerase chain reaction fingerprinting with a nonspecific single primer, T3B, yielded distinct profiles for type strains and for the clinical isolates, suggesting that some of the isolates represented previously undescribed species. Growth of these species took greater than or equal to 5 days; therefore, laboratories should incubate anaerobic plates from bite wound cultures for greater than or equal to 7 days to assure isolation of these common pathogens.