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United States Department of Agriculture

Agricultural Research Service

Research Project: Pre-Harvest Interventions For Application During Poultry Production To Reduce Food-Borne Bacterial Pathogens

Location: Poultry Microbiological Safety Research

Title: Prevalence, development, and molecular mechanisms of bacteriocin resistance in Campylobacter.

Authors
item Hoang, Ky Van -
item Stern, Norman
item Saxton, Arnold -
item Xu, Fuzhou -
item Zeng, Ximin -
item Lin, Jun -

Submitted to: Applied and Environmental Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 21, 2011
Publication Date: April 1, 2011
Citation: Hoang, K., Stern, N.J., Saxton, A.M., Xu, F., Zeng, X., Lin, J. 2011. Prevalence, development, and molecular mechanisms of bacteriocin resistance in Campylobacter.. Applied and Environmental Microbiology. 2011 Apr;77(7):2309-16. Epub 2011 Jan 28..

Interpretive Summary: Campylobacteriosis is an infectious human food-borne disease caused by bacteria of the genus Campylobacter and it is one of the most common causes of human diarrheal illness in the United States. These bacteria are commonly associated as a commensal in the gastrointestinal (GI) tracts of poultry where birds show no signs of illness to the bacteria. Most cases of campylobacteriosis are associated with eating raw or undercooked poultry meat or from cross-contamination of other foods by these items. Bacteriocins (BCNs) are antimicrobial peptides produced by lactic acid bacteria (LAB) with narrow or broad spectra of antimicrobial activity. Recently, several unique anti-Campylobacter BCNs have been identified from commensal LAB isolated from chicken intestines. These BCNs dramatically reduced C. jejuni colonization in the GI tract of poultry and are being directed toward on-farm control of Campylobacters to reduce food-borne human disease. In this study 137 C. jejuni isolates and 20 C. coli isolates were examined to determine the bacteria’s susceptibilities to the anti-Campylobacter BCNs OR-7 and E-760. Only one C. coli strain displayed resistance to the BCNs, while other campylobacters were all susceptible to inactivation by the antimicrobial peptides. A multidrug efflux pump gene was determined to be responsible for resistance to BCNs. This study represents the first report of and a major step forward in understanding BCN resistance among Campylobacters, which will facilitate the development of effective BCN-based control strategies to reduce the numbers of these bacteria in poultry to lower human food-borne disease.

Technical Abstract: Bacteriocins (BCNs) are antimicrobial peptides produced by lactic acid bacteria (LAB) with narrow or broad spectra of antimicrobial activity. Recently, several unique anti-Campylobacter BCNs have been identified from commensal LAB isolated from chicken intestines. These BCNs dramatically reduced C. jejuni colonization in poultry and are being directed toward on-farm control of Campylobacters to reduce human food-borne disease. However, no information concerning prevalence, development and mechanisms of BCN resistance in Campylobacter exists. In this study, 137 C. jejuni isolates and 20 C. coli isolates were examined for their susceptibilities to the anti-Campylobacter BCNs OR-7 and E-760. Only one C. coli strain displayed resistance to the BCNs (MIC, 64 ug/ml), while others were highly susceptible, with MICs ranging from 0.25 to 4 ug/ml. The C. coli mutants resistant to BCN OR-7 were also obtained by in vitro selection, but all displayed only low-level resistance to OR-7 (MIC, 8 to 16 ug/ml). The acquired BCN resistance in C. coli could be transferred at intra- and interspecies levels among Campylobacter strains by biphasic natural transformation. Genomic examination of the OR-7-resistant mutants by using DNA microarray and random transposon mutagenesis revealed that the multidrug efflux pump CmeABC contributes to both intrinsic resistance and acquired resistance to the BCNs. Altogether, this study represents the first report of and a major step forward in understanding BCN resistance among Campylobacters, which will facilitate the development of effective BCN-based strategies to reduce the numbers of these bacteria in poultry to lower human food-borne disease.

Last Modified: 7/24/2014
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