Evaluation of the API-campy system in the biochemical identification of hippurate negative campylobacter strains isolated from faeces.

The aim was to evaluate the efficacy of the API-Campy system in the biochemical identification of 62 hippurate negative campylobacter strains isolated from the faeces. The strains were identified manually as 34 nalidixic acid susceptible C coli (NAS), 20 nalidixic acid resistant C coli (NAR), and eight C lari. The 34 strains of NAS C coli were identified as such by the API-Campy system. Of the 20 strains of NAR C coli, 15 (75%) were correctly identified by the commercial system. None of the five NAR C coli strains which were also erythromycin resistant was identified as such by the system. The eight C lari strains could not be identified by the API-Campy system because the bionumber obtained does not exist in the database of the computer system. The API-Campy system could be very useful for the identification of NAS C coli. However, failure to allow for a higher percentage of resistance to nalidixic acid in this species does not permit good identification of NAR strains. More important discrepancies are observed in C lari strains. In order to improve the identification of NAR C coli and C lari stains, it is advisable to include, or recommend as complementary, the indoxyl acetate hydrolysis test.