An evaluation of the Oxoid Biochemical Identification System Campy rapid screening test for Campylobacteraceae and Helicobacter spp.

AIMS: To evaluate the Oxoid Biochemical Identification System (OBIS) Campy test (ID0800M) against Campylobacter; Arcobacter; and other micro-organisms, with similar colonial morphology, for the detection of l-alanine aminopeptidase (l-ALA). METHODS AND
RESULTS: The KOH and l-ALA (OBIS and Fluka) tests were carried out on every isolate. The procedures were followed as indicated in the OBIS and Fluka kit instructions. A total of 146 strains of 19 species of Campylobacter, seven strains of Arcobacter butzleri, four Arcobacter butzleri-like strains, 42 strains of 10 species of Helicobacter, 96 Gram-negative and 49 Gram-positive clinical isolates were tested. As expected, Campylobacter and Arcobacter strains were negative, while other Gram-negative bacteria were positive for the l-ALA test. An unexpected finding was that Helicobacter strains, although Gram-negative, were all negative for the l-ALA tests suggesting the absence of l-ALA within this genus. This is a novel finding. The absence of l-ALA was confirmed upon comparison with the available full genomic sequences of Helicobacter on the NCBI database.
CONCLUSIONS: The OBIS Campy (ID0800M) test kit proved to be rapid and accurate for the presumptive characterization of Campylobacter and Arcobacter. A novel finding was that Helicobacter species also did not have the l-ALA enzyme. SIGNIFICANCE AND IMPACT OF THE STUDY: The OBIS kit will be useful in diagnostic laboratories for the presumptive diagnosis of Campylobacter, Arcobacter and Helicobacter strains.