Comparison of the Nucleic Acid Amplification System NASBA^® and Agar Isolation for Detection of Pathogenic...

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^®, 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. coli , five (3.12%) as C. lari , and two (1.25%) as unclassified. The NASBA^® 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^® 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^® system was used. However, the high sensitivity of the NASBA^® 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^® 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.