Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/20/2004
Publication Date: 5/20/2004
Citation: Mandrell, R.E., Brandl, M. 2004 Campylobacter species and fresh produce: outbreaks, incidence and biology. In: Beier,R.C., Pillai,S.D., Phillips,T.D., and Ziprin,R.L., editors. Preharvest and Post Harvest Food Safety: Contemporary Issues and Future Directions. IFT Press and Blackwell publishing, Ames, IA. p. 59-72
Interpretive Summary: Campylobacter species other than the most commonly known, C. jejuni and C. coli, are emerging as pathogens in other parts of the world. The methods for isolating common Campylobacter are not effective at isolating many of the more fastidious and antibiotic sensitive species. We are collaborating in sequencing the genomes of a number of the emerging Campylobacter species and have identified a number of interesting genes and gene loci that are potential virulence factors related to both human illness and colonization of animals. The licABCD locus in C. upsaliensis strains obtained from South Africa may be a marker for two different groups of C. upsaliensis strains and likely is a virulence factor. The factors identified in these Campylobacter will help in species identification methods and strain differentiation, and analysis of the incidence of this emerging pathogen in foods and the environment. This information may help in determining whether these organisms are in food and are responsible for sporadic human illness.
Technical Abstract: Campylobacter upsaliensis (Cups) is a thermophilic Campylobacter species that has been isolated routinely in South Africa (SA) from diarrheal stool samples of patients by a non-selective filtration method. Examination of preliminary genome sequence data for a SA strain of Cups (RM3195) isolated from the feces of a child with Guillain-Barré Syndrome, revealed a putative licABCD locus. licABCD putatively encodes proteins in Haemophilus influenzae, commensal Neisseria and Streptococcus pneumonia involved in acquisition of choline (licB), synthesis of phosphorylcholine (PCho) (licA,C) and transfer of PCho (licD) to outer membrane or cell wall molecules; PCho-decorated molecules are probable virulence factors. Primers were designed from the Cups licA homolog (licA encodes a choline kinase in other pathogens) and used in PCR to determine the incidence of licA in clinical isolates of Cups from SA, and from human and animal Cups isolates from Europe and North America. Twenty-seven of 28 (96%) Cups strains from SA were licA+ compared to 2 of 22 (8%) non-SA isolates. A monoclonal antibody (MAb) specific for PCho bound to 100% of the licA+ strains tested by ELISA, but not to any licA- strains. Immunochemical analysis of licA+ strains on colony blots and individual cells by microscopy revealed variable expression of the PCho antigen; intra-strain differences in PCho expression were detected also. Variable expression was due probably slipped-strand mispairing during replication due to poly-G nucleotide tracts present at the 5' end of licA. Sequencing of 16S rDNA genes of Cups strains revealed that SA strains were related, but differed significantly from the non-SA strains. We conclude that most clinical isolates of SA Cups strains are licA+ and variably express PCho. The difference in licA incidence among Cups could be due to differences in isolation and identification methods (e.g. non-selective vs. selective) or selection of strains through socioeconomic, geographic and/or host differences.