Prevalence and characterization of Campylobacter jejuni isolated from pasture flock poultry.
ABSTRACT The growing interest in organic and natural foods warrants a greater need for information on the food safety of these products. In this study, samples were taken from 2 pasture flock farms (N = 178; feed, water, drag swabs, and insect traps), pasture flock retail carcasses (N = 48) and 1 pasture flock processing facility (N = 16) over a period of 8 mo. A total of 105 Campylobacter isolates were obtained from 53 (30%), 36 (75%), and 16 (100%) samples from the farms, retail carcasses, and processing facility, respectively. Of the 105 isolates collected, 65 were C. jejuni, 31 were C. coli, and 9 were other Campylobacter spp. Using PCR, the C. jejuni isolates were further analyzed for virulence genes involved in colonization and survival (flaA, flaC, cadF, dnaJ, racR, cbrR), invasion (virB11, ciaB, pldA), protection against harsh conditions (sodB, htrA, clpA), toxin production (cdtA, cdtB, cdtC), siderophore transport (ceuE), and ganglioside mimicry (wlaN). In addition, the short variable region of the flaA locus (flaA SVR) was sequenced to determine the genetic diversity of the C. jejuni isolates. The flaA SVR diversity indices increased along the farm to carcass continuum. PCR-based analysis indicated a low prevalence of 5 genes involved in colonization (dnaJ, ciaB, pldA, racR, virB11). The results of this survey indicate that the prevalence of Campylobacter on organic retail carcasses is similar to prevalence reports of Campylobacter on conventional retail carcasses. However, the genetic diversity of the flaA SVR genotypes increased along the farm to carcass continuum that contrasted with conventional poultry studies. PRACTICAL APPLICATION: Campylobacter jejuni is a leading cause of foodborne illness with poultry and poultry products being leading sources of infection. Free-range and pasture flock chickens are becoming more popular; however, there is an inherent biosecurity risk that can increase the prevalence of foodborne pathogens in these flocks. This study aimed to determine sources and characterize C. jejuni isolated from pasture flocks.
- SourceAvailable from: ncbi.nlm.nih.gov[show abstract] [hide abstract]
ABSTRACT: A genomic library of Campylobacter jejuni (NCTC 11351) was used to identify genes which could confer a hemolytic phenotype to Escherichia coli. Accordingly, when transformants were screened on blood plates, hemolytic colonies appeared at a frequency of 3 x 10(-4). The gene conferring the hemolytic activity was identified by subcloning and was found to be responsible for the phenotype of all hemolytic transformants isolated. The open reading frame conferring this activity encodes a protein of 36,244 Da with a typical endopeptidase type II leader sequence. The protein is modified with palmitic acid when it is processed in E. coli, confirming that it is a typical lipoprotein. The deduced gene product of 329 amino acids has significant homology to the group of solute binding proteins from periplasmic-binding-protein-dependent transport systems for ferric siderophores, including the FatB protein from Vibrio anguillarium and the FhuD protein from Bacillus subtilis. In particular, the protein contained the signature sequence for siderophore-binding proteins, suggesting that the protein may be the siderophore-binding protein component of an iron acquisition system of C. jejuni.Journal of Bacteriology 06/1995; 177(9):2259-64. · 3.19 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: A gene (pldA) encoding a 35.0-kDa protein with significant homology to the Escherichia coli outer membrane phospholipase was identified upstream of an operon encoding an enterochelin transport system in Campylobacter coli. The results of this study suggest that this gene encodes an outer membrane phospholipase A in C. coli. First, expression of the pldA gene product in a PldA-deficient mutant of E. coli led to the restoration of phospholipase A activity. The recombinant product also partitioned to the outer membrane, suggesting that it may be similarly located in C. coli. Second, heterologous overexpression in E. coli, followed by in vitro folding and purification of C. coli PldA, resulted in pure protein which displayed calcium-dependent lysophospholipase and phospholipase A activities in vitro. Finally, mutants of C. coli in which the pldA gene had been inactivated by allelic exchange were deficient in phospholipase A activity. Phospholipases are associated with lysis of erythrocytes by a number of bacterial pathogens. The pldA mutant was shown to have a reduced hemolytic activity compared to the wild-type strain, suggesting a role for the phospholipase A in the lysis of erythrocytes by C. coli. Since hemolysins are intimately associated with the disease-causing potential of a number of bacterial pathogens, it is likely that the phospholipase A plays some role in Campylobacter virulence.Infection and Immunity 05/1997; 65(4):1172-80. · 4.07 Impact Factor
- [show abstract] [hide abstract]
ABSTRACT: A PCR method for the rapid identification and discrimination of thermophilic Campylobacter jejuni and Campylobacter coli was developed by using a gene encoding a protein involved in siderophore transport (ceuE). A nucleotide sequence divergence of approximately 13% in the ceuE genes of C. jejuni and C. coli facilitated the design of two species-specific PCR primer sets. The specificity of the PCR amplification reactions was confirmed by using two nonradioactively labelled species-specific internal oligonucleotide hybridization probes for each of these species.Journal of Clinical Microbiology 04/1997; 35(3):759-63. · 4.07 Impact Factor