Comparison of the nucleic acid amplification system NASBA(R) and agar isolation for detection of pathogenic campylobacters in naturally contaminated poultry

Abstract

A total of 160 poultry products were examined for the presence of pathogenic campylobacters using the traditional agar isolation method and the nucleic acid amplification system NASBA(R), both after a 24-h selective enrichment. Pathogenic campylobacters could be isolated from 92 of 160 (57.5%) samples using agar isolation, among which 79 (49.37%) were identified as Campylobacter jejuni six (3.75%) as C. coil, five (3.12%) as C. lari, and two (1.25%) as unclassified. The NASBA(R) assay provides a specific and sensitive method for detection of these campylobacters. A total of 149 samples (93.12%) gave similar results for both the traditional isolation procedure on modified Campylobacter charcoal desoxycholate agar and the NASBA(R) enzyme-linked gel assay detection system. Two false-negative results were obtained with the agar isolation procedure. Nine false-positive results were reported when the NASBA(R) system was used. However, the high sensitivity of the NASBA(R) method and indications that in some cases the traditional isolation procedure failed (abundance of a contaminating noncampylobacter bacteria which grew on the Campylobacter selective media) raises doubt about the true nature of these false-positive results. The NASBA(R) detection assay offers a rapid and useful analytical method when screening for the presence of pathogenic campylobacters. The complete procedure, including 24 h of selective enrichment, required 32 h