Accuracy of the API Campy system, the Vitek 2 Neisseria-Haemophilus card and matrix-assisted laser desorption ionization time-of-flight mass spectrometry for the identification of Campylobacter and related organisms.

Abstract

Biochemical identification of Campylobacter and related organisms is not always specific, and may lead to diagnostic errors. The API Campy, the Vitek 2 system and matrix-assisted desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) are commercially available methods that are routinely used for the identification of these microorganisms. In the present study, we used 224 clinical isolates and ten reference strains previously identified by multiple PCR assays, whole cell protein profiling and either DNA-DNA hybridization or sequencing analysis to compare the reliability of these three methods for the identification of Campylobacter and related pathogens. The API Campy accurately identified 94.4% of Campylobacter jejuni ssp. jejuni and 73.8% of Campylobacter coli, but failed to correctly identify 52.3% of other Epsilobacteria. The Vitek 2 Neisseria-Haemophilus card correctly identified most C. jejuni ssp.jejuni (89.6%) and C. coli (87.7%) strains, which account for the majority of campylobacterioses reported in humans, but it failed in the identification of all of the other species. Despite a good identification rate for both C. jejuni ssp. jejuni and C. coli, both methods showed poor sensitivity in the identification of related organisms, and additional tests were frequently needed. In contrast to API Campy and Vitek, MALDI-TOF MS correctly identified 100% of C. coli and C. jejuni strains tested. With an overall sensitivity of 98.3% and a short response time, this technology appears to be a reliable and promising method for the routine identification of Campylobacter and other Epsilobacteria.