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Fluoroquinolone-resistant Campylobacter in animal reservoirs: dynamics of development, resistance mechanisms and ecological fitness

Published online by Cambridge University Press:  28 February 2007

Qijing Zhang ,
Jun Lin  and
Sonia Pereira
Qijing Zhang*
Affiliation:
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, USA
Jun Lin
Affiliation:
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, USA
Sonia Pereira
Affiliation:
Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA, USA
*
*Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, 1116 Veterinary Medicine Bldg., Ames, IA 50011, USA E-mail: zhang123@iastate.edu
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Abstract

Thermophilic Campylobacter species, including Campylobacter jejuni and Campylobacter coli, are responsible for foodborne campylobacteriosis in humans and are increasingly resistant to fluoroquinolone (FQ) antimicrobials. The therapeutic use of FQ antimicrobial agents in food animal production, particularly in poultry, has become a concern for public health, because the practice may promote the emergence of FQ-resistant Campylobacter that can be transmitted to humans through the food chain. Recent studies have indicated that Campylobacter displays a hypermutable phenotype in response to in vivo treatment with FQ antimicrobials, resulting in the rapid emergence of resistant mutants. Distinct from other Gram-negative bacteria, the acquisition of FQ resistance in Campylobacter does not require stepwise accumulation of gyrA mutations and overexpression of efflux pumps, and is mainly mediated by single-step point mutations in gyrA in the presence of a constitutively expressed multidrug efflux pump, CmeABC. The simplicity of the resistance mechanisms may facilitate the rapid adaptation of Campylobacter to FQ treatment. The FQ-resistant Campylobacter mutants derived from chickens do not show a fitness cost in vivo and are ecologically competitive in the colonization of chickens even in the absence of antimicrobial selection pressure. These findings suggest that FQ-resistant Campylobacter may continue to persist regardless of antimicrobial usage, and highlight the need for extra effort to prevent the occurrence and spread of FQ-resistant Campylobacter in animal reservoirs.

Keywords

fluoroquinoloneantimicrobialantibioticCampylobacterresistancepoultry
Type
Research Article
Information
Animal Health Research Reviews , Volume 4 , Issue 2 , December 2003 , pp. 63 - 72
Copyright
Copyright © CAB International 2003

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