Direct detection of thermotolerant campylobacters in chicken products by PCR and in situ hybridization

We have evaluated the use of PCR and fluorescent in situ hybridization (FIS H) techniques for the detection of thermotolerant campylobacters in natural ly contaminated chicken products. 16S rRNA sequence data was used to design two specific primers and an oligonucleotide probe for PCR and FISH analyse s, respectively. The PCR protocol amplified a 439-bp fragment corresponding to a portion of specific 16S RNA gene from thermotolerant campylobacters. The detection range of the PCR assay varied between 10 cells (after enrichm ent) to 10(2) cells per mL (without enrichment). FISH probes were able to i dentify thermotolerant Campylobacter species in 'spiked' and 'unspiked' nat urally contaminated samples. PCR and FISH were performed on naturally conta minated samples and compared with the isolation of cells on selective media . The in situ hybridization technique was less sensitive than PCR, although its sensitivity of detection was increased considerably after 22 h of enri chment. These results confirm the usefulness of 16S rRNA-based techniques f or the direct detection of campylobacters in food samples. (C) 2001 Edition s scientifiques et medicales Elsevier SAS.