Multiplex PCR assay (m-PCR) with three sets of primers was developed for simultaneous identification of Campylobacter jejuni and C. coli. Poultry faecal samples were enriched in Preston broth for 24 h and streaking on selective media was performed before and after enrichment. m-PCR was applied on bacterial cultures harvested from media plates. The data showed a selective effect of Preston broth which favoured the growth of C. coli. Identification of the species by the hippurate hydrolysis test and by the m-PCR was performed on 294 isolates of Campylobacter. The efficiency of the identification by the biochemical test is only 34% in comparison to 100% efficiency with the PCR. The use of our m-PCR in combination with the culture method allowed reliable detection and identification of C. jejuni and C. coli within 3-4 d.

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Campylobacter jejuni is a microaerophilic pathogen but is able to survive oxidative stress conditions during its transmission to the human host. Strains of different origins (reference, poultry, or human clinical) were tested for survival under oxidative stress conditions. C. jejuni strains were grown in Mueller Hinton broth to obtain late exponential-phase cultures. Then they were exposed to 2 different stresses: (1) cultures were either plated on Columbia agar plates and exposed to atmospheric oxygen or (2) paraquat (a chemical oxidizing agent) was added to liquid cultures to reach a 500-microM concentration. Both of these experimental conditions were realized at 3 different temperatures: 4 degrees C, 25 degrees C, and 42 degrees C. Results obtained with paraquat and atmospheric oxygen were similar. Surprisingly, C. jejuni was found to be very sensitive to oxidative stress at 42 degrees C, which is its optimal growth temperature, whereas it was more resistant at 4 degrees C. A strain effect was observed, but no relationship was found between the origin of the strains and level of resistance. High temperature (42 degrees C) combined with oxidative stress allowed a rapid decrease in the C. jejuni population, whereas low temperature considerably decreased the effect of oxidative stress.

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Aims: Campylobacter contamination in French chicken production from the farm to the consumer was determined using a PCR assay for bacteria detection and identi®cation. Methods and Results: Samples were bird droppings from poultry houses, neck skins, livers, hearts, gizzards, wings, legs and escalopes from slaughterhouses and gizzards, legs, drumstick, breast and escalopes from a supermarket. Bacterial DNA extraction was performed after an enrichment step in a broth and was followed by PCR. An internal control (IC) was used for both DNA extraction and PCR. Campylobacter were detected in 79á2% of poultry houses. Of the 303 samples, 201 were Campylobacter-positive (i.e. 66á3%) including 43á2% faecal samples, 5á6% slaughterhouse samples and 17á5% supermarket samples. There was no signi®cant difference between the molecular method and the conventional culture technique for Campylobacter detection whatever the samples. The sensitivity was 5 UFC g)1 of samples and 1á5´10 3 UFC ml )1 of enrichment broth. The use of IC revealed PCR inhibition in 13 samples and problems in the DNA extraction in ®ve samples. Conclusions: Signi®cant Campylobacter contamination affects all stages of French chicken production. Signi®cance and Impact of the Study: The understanding of Campylobacter contamination at different levels of chicken production and the determination of the best place(s) for intervention are important for signi®cantly decreasing Campylobacteriosis. Our technique is rapid and can be used on different chicken samples for Campylobacter detection and identi®cation.