Detection of Campylobacter jejuni from the skin of broiler chickens, ducks, squab, quail, and guinea fowl carcasses.

Campylobacter jejuni is often found on broiler carcasses and can cause gastroenteritis in humans. Both carcass rinses and swabs of the skin have been utilized to ascertain the prevalence of C. jejuni in the processing plant. Not all poultry commodities are equally capable of carrying C. jejuni on the carcass skin. Our objective was to measure the probability of C. jejuni detection (sensitivity) for the skin swabbing method followed by enrichment in semisolid media, and to ascertain the sensitivity of this method for commercial broiler, duck, squab, quail, and guinea fowl. The probability of detecting skin contaminated with C. jejuni was significantly higher for broiler chicken compared to retail duck, squab, quail, or guinea fowl for 10 or 100 colony-forming units (CFU)/in2 of skin (1 in2 = 1 square inch = 2.5 x 2.5 cm). Thirty-three percent (10 CFU/in2) and 100% (100 CFU/in2) of skin samples from broilers were positive for C. jejuni at the levels inoculated while 7-20% and 47-80% of skin samples were detected as contaminated with C. jejuni at 10 or 100 CFU/in2 for retail duck, squab, quail, and guinea fowl, respectively. Our method of using skin swabs and enrichment with semisolid media generated a sensitivity of almost 100% for detecting C. jejuni at 1000 or 10,000 CFU/in2 skin regardless of poultry species. The level of contamination that our method could detect with 50% and 90% reliability (DT50 and DT90) was 14 and 79 (broilers); 67 and 406 (squab); 39 and 226 (quail); 69 and 400 (guinea fowl); 69 and 400 (duck) CFU/in2 of skin, respectively.

Diversity of flaA genotypes among Campylobacter jejuni isolated from six niche-market poultry species at farm and processing.

PCR-restriction fragment length polymorphism of the flagellin (flaA) gene in Campylobacter jejuni was used to determine the relationships of isolates collected at the farm and throughout processing for six niche-market poultry species. This study focused on two specialty chicken products, poussin and free range, and four other specialty products, squab, duck, guinea fowl, and quail. Cloacal and carcass samples were collected from three flocks from each of the six niche species. Three processing plants in California participated in a 2-year investigation. A total of 773 isolates from farm, posttransport, and the processing plants were genotyped, yielding a total of 72 distinct flaA profiles for the six commodities. Genetic diversity of C. jejuni at the farm was greatest for ducks with up to 12 distinct flaA types in two flocks and least for squab 1 flaA type between two farms. For two of the guinea fowl flocks, one free-range flock, two squab flocks, and all three poussin flocks, the flaA types recovered at the prepackage station matched those from the farm. Cross-contamination of poultry carcasses was supported by the observation of flaA types during processing that were not present at the farm level. New C. jejuni strains were detected after transport in ducks, guinea fowl, and free-range chickens. Postpicker, postevisceration, and prewash sampling points in the processing plant yield novel isolates. Duck and free-range chickens were the only species for which strains recovered within the processing plant were also found on the final product. Isolates recovered from squab had 56 to 93% similarity based on the flaA types defined by PCR-restriction fragment length polymorphism profiles. The 26 duck isolates had genetic similarities that ranged from 20 to 90%. Guinea fowl and free-range chickens each had 40 to 65% similarity between isolates. Poussin isolates were 33 to 55% similar to each other, and quail isolates were 46 to 100% similar. Our results continue to emphasize the need to clean processing equipment and posttransport crates in order to decrease cross contamination between flocks. This study also determined that several strains of C. jejuni had unique flaA types that could only be recovered in their host species.

Colonizing capability of Campylobacter jejuni genotypes from low-prevalence avian species in broiler chickens.

Genetic variations in Campylobacter jejuni or host factors result in low prevalence rates among nonchicken poultry species. The objective of this study was to determine the colonizing potential, in broiler chickens, of C. jejuni that was recovered from low-prevalence avian species. Twenty-day-old Campylobacter-negative broiler chicks were inoculated by oral gavage with genetically different primary isolates of C. jejuni recovered from squab, duck, or chicken. Serial sampling and microbiologic testing of ceca were used to determine the level of colonization and the prevalence of positive chickens. All isolates were recovered from chickens by 10 days postinoculation. The C. jejuni strains recovered from challenged birds were genetically identical to the inoculated strains. By 10 days postinoculation, treatment groups inoculated with duck or control chicken isolates were 100% positive. The level of colonization by the squab isolate on day 2 postinoculation was significantly less than the duck or chicken isolates and had not colonized all birds by day 10 postinoculation.

Prevalence of Campylobacter and Salmonella species on farm, after transport, and at processing in specialty market poultry.

The prevalence of Campylobacter and Salmonella spp. was determined from live bird to prepackaged carcass for 3 flocks from each of 6 types of California niche-market poultry. Commodities sampled included squab, quail, guinea fowl, duck, poussin (young chicken), and free-range broiler chickens. Campylobacter on-farm prevalence was lowest for squab, followed by guinea fowl, duck, quail, and free-range chickens. Poussin had the highest prevalence of Campylobacter. No Salmonella was isolated from guinea fowl or quail flocks. A few positive samples were observed in duck and squab, predominately of S. Typhimurium. Free-range and poussin chickens had the highest prevalence of Salmonella. Post-transport prevalence was not significantly higher than on-farm, except in free-range flocks, where a higher prevalence of positive chickens was found after 6 to 8 h holding before processing. In most cases, the prevalence of Campylobacter- and Salmonella-positive birds was lower on the final product than on-farm or during processing. Odds ratio analysis indicated that the risk of a positive final product carcass was not increased by the prevalence of a positive sample at an upstream point in the processing line, or by on-farm prevalence (i.e., none of the common sampling stations among the 6 commodities could be acknowledged as critical control points). This suggests that hazard analysis critical control point plans for Campylobacter and Salmonella control in the niche-market poultry commodities will need to be specifically determined for each species and each processing facility.

Virulence factors of Escherichia cofi from cellulitis or colisepticemia lesions in chickens.

This study was designed to compare virulence factors of cellulitis-derived Escherichia coli to colisepticemic E. coli in order to clarify whether E. coli associated with cellulitis comprise a unique subset of pathogenic E. coli. Isolates were tested for serotype, capsule, aerobactin production, colicin production, the presence of the iss gene, and serum resistance. Untypable isolates made up the greatest percentage of each group. Serotypes O2 and O78 were the most commonly identified among both groups of isolates. No statistical differences in the distribution of aerobactin or colicin production, capsule, or iss gene were observed between groups. Cluster analysis showed that 90% of the E. coli isolates had greater than 42% livability in serum-resistance tests. No separation of colisepticemic vs. cellulitis E. coli isolates was observed on the basis of SR. Colicin production by E. coli was highly correlated with serum resistance (P = 0.0029). These data suggest that cellulitis E. coli have virulence traits similar to those of colisepticemic E. coli.

Prevalence of campylobacter spp. from skin, crop, and intestine of commercial broiler chicken carcasses at processing.

This study describes the prevalence of positive Campylobacter cultures from the skin, crop, and intestine of postscald broiler chicken carcasses at processing. Six to 12 carcasses from 22 flocks were sampled. Skin was cultured by direct plating of a cotton swab, whereas crop and intestine were cultured from tissue that was aseptically harvested and stomached in PBS before plating. Cultures were not enriched prior to plating. The methods used in this report are compared to those used by others. In this study, skin samples were 78% positive; crops were 48% positive, and intestines were 94% positive (n = 202). Based on our results, if the intestine was positive for Campylobacter, the odds of finding a positive crop culture was 8.6 times greater, and the odds of finding a positive skin culture was 35 times greater than if the intestinal culture was negative for Campylobacter. These data suggest that the intestine was the most likely organ of those tested to be positive in postscald broiler carcasses from positive flocks. Further, if only one organ can be sampled, intestinal samples are most likely to reflect the prevalence of Campylobacter in a flock.