The diversity of Campylobacter spp. throughout the poultry processing plant

Campylobacteriosis is the leading food-borne disease in developed countries, and poultry are a major source for human infection. The diversity of Campylobacter on chicken carcasses during processing may lead to isolates that are able to survive abattoir processing. This has important implications for public health and adds a further layer to the complexity of the epidemiology of campylobacteriosis. The diversity of the Campylobacter spp. populations on broiler carcasses was studied at three different stages of processing (post-bleed, post-scald and post-chill) in three UK processing plants, using the pulsed-field gel electrophoresis (PFGE) KpnI enzyme. One hundred and sixty Campylobacter strains from 3 processing plants were identified as C. jejuni (92.3%) with 27 PFGE subtype profiles recovered from carcasses at the post-bleed point. Change in populations was identified when carcasses move towards the end of poultry processing. Seven C. jejuni genotypes were able to survive the scalding tank stage process, and 5 genotypes surviving the entire poultry process. Confirmation by PFGE gives information on the genotypic profiles of C. jejuni on chicken carcasses and how they change according to the temperatures exposed to during processing. Diversity within C. jejuni populations produces genotypes that adapt to tolerate the processing environment, and these may be capable of causing human disease. Understanding more about the genotypes that survive the processing will have important implications for public health.

Application of pulsed field gel electrophoresis to type Campylobacter jejuni

Pulsed field gel electrophoresis (PFGE) is generally accepted as one of the most discriminatory methods available for genotyping Campylobacter jejuni. PFGE has been extensively used in epidemiological studies, including outbreak investigation, persistence of genotypes in a human population, environmental diversity of sporadic infection isolates, dissemination of antibiotic-resistant strains, and comparison of genotypes within and between hosts. The main purpose of this chapter is to present a working PFGE protocol for those interested in incorporating this technique in their laboratories.

Technical note: a rapid pulsed-field gel electrophoresis method for analysis of bifidobacteria

Pulsed-field gel electrophoresis (PFGE) is a widely used and highly discriminatory molecular typing method that has been applied to bifidobacteria. However, published PFGE protocols used with bifidobacteria require between 5 and 7 d to complete. A rapid PFGE method was developed that can be completed within 24 h.

Genomic diversity of Campylobacter coli and Campylobacter jejuni isolates recovered from free-range broiler farms and comparison with isolates of various origins

In many industrialized countries, the incidence of campylobacteriosis exceeds that of salmonellosis. Campylobacter bacteria are transmitted to humans mainly in food, especially poultry meat products. Total prevention of Campylobacter colonization in broiler flocks is the best way to reduce (or eliminate) the contamination of poultry products. The aim of this study was to establish the sources and routes of contamination of broilers at the farm level. Molecular typing methods (DNA macrorestriction pulsed-field gel electrophoresis and analysis of gene polymorphism by PCR-restriction fragment length polymorphism) were used to characterize isolates collected from seven broiler farms. The relative genomic diversity of Campylobacter coli and Campylobacter jejuni was determined. Analysis of the similarity among 116 defined genotypes was used to determine clusters within the two species. Furthermore, evidence of recombination suggested that there were genomic rearrangements within the Campylobacter populations. Recovery of related clusters from different broiler farms showed that some Campylobacter strains might be specifically adapted to poultry. Analysis of the Campylobacter cluster distribution on three broiler farms showed that soil in the area around the poultry house was a potential source of Campylobacter contamination. The broilers were infected by Campylobacter spp. between days 15 and 36 during rearing, and the type of contamination changed during the rearing period. A study of the effect of sanitary barriers showed that the chickens stayed Campylobacter spp. free until they had access to the open area. They were then rapidly colonized by the Campylobacter strains isolated from the soil.

Role of real-time molecular typing in the surveillance of Campylobacter enteritis and comparison of pulsed-field gel electrophoresis profiles from chicken and human isolates

The goal of the present study was to assess the contribution of real-time molecular typing, used alone or with clinical surveillance, to the prompt identification of clusters of Campylobacter enteritis. Potential poultry sources were sought by comparing the pulsed-field gel electrophoresis genotypes of human and fresh whole retail chicken isolates collected during the same study period. Among 183 human isolates, 82 (45%) had unique genotypes, 72 (39%) represented 26 clusters of 2 to 7 isolates each, and 29 (16%) represented three clusters of 8 to 11 isolates each. Molecular typing was useful for the confirmation of outbreaks suspected on the basis of epidemiological surveillance, but for most small clusters, no epidemiological link could be established. Thus, the added value of real-time molecular typing is questionable, since the numerous small clusters identified were of unclear public health significance. Among 177 chickens, 41 (23%) yielded campylobacter isolates; of these, 19 (46%) had genotypes similar to those of 41 (22%) human isolates. However, a temporal association was demonstrated in only a minority of cases, and most genotypes were present only in a single species, suggesting that sources other than chickens are important in human campylobacteriosis. Further investigation with samples from water and other possible environmental sources is needed to define the most efficient strategy for the application of molecular typing and identification of the source(s) of sporadic cases of campylobacteriosis.

Cluster of erythromycin- and ciprofloxacin-resistant Campylobacter jejuni subsp. jejuni from 1999 to 2001 in men who have sex with men, Québec, Canada

From December 1999 to November 2001, a cluster of multidrug-resistant Campylobacter jejuni subsp. jejuni enterocolitis was suspected within the male population of Montreal. Nine men, aged 26-40 years, presented with an erythromycin- and ciprofloxacin-resistant, tetracycline-susceptible C. jejuni enterocolitis. In March 1998 and February 2000, 2 additional men, aged 23 and 27 years, were infected with an erythromycin-resistant, ciprofloxacin and tetracycline-susceptible C. jejuni. All isolates were identical according to pulsed-field gel electrophoresis and flagellin typing. Epidemiological data suggested a sexually transmitted enteric infection; all patients infected with the locally acquired epidemic strain were men, the 8 patients for whom sexual orientation data were available identified themselves as men who have sex with men (MSM), and 3 of the patients had had a sexually transmitted Shigella sonnei infection during a proven outbreak among MSM. Eight patients, 6 of whom were identified as MSM, resided in a predominantly homosexual district of Montreal or its surrounding neighborhoods. The emergence of multidrug-resistant C. jejuni justifies routine susceptibility-testing of these bacteria. MSM should be educated about the prevention of sexually transmitted enteric pathogens.