This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Alcaine, S. D. Articles by Wiedmann, M. Search for Related Content PubMed PubMed Citation Articles by Alcaine, S. D. Articles by Wiedmann, M.

 Previous Article  |  Next Article 

Antimicrobial Agents and Chemotherapy, October 2005, p. 4061-4067, Vol. 49, No. 10
0066-4804/05/$08.00+0     doi:10.1128/AAC.49.10.4061-4067.2005
Copyright © 2005, American Society for Microbiology. All Rights Reserved.

Ceftiofur-Resistant Salmonella Strains Isolated from Dairy Farms Represent Multiple Widely Distributed Subtypes That Evolved by Independent Horizontal Gene Transfer

Department of Food Science,¹ Department of Population Medicine and Diagnostic Sciences, Cornell University, Ithaca, New York 14853²

Received 26 April 2005/ Returned for modification 30 May 2005/ Accepted 2 August 2005

Salmonella is the leading cause of known food-borne bacterial infections in the United States, with an incidence rate of approximately 15 cases per 100,000 people. The rise of antimicrobial-resistant Salmonella subtypes, including the appearance of subtypes resistant to ceftriaxone, represents a particular concern. Ceftriaxone is used to treat invasive cases of Salmonella in children and is closely related to ceftiofur, an antibiotic commonly used to treat diseases of cattle. In order to develop a better understanding of the evolution and transmission of ceftiofur resistance in Salmonella, we characterized ceftiofur-resistant and -sensitive Salmonella isolates from seven New York dairy farms. A total of 39 isolates from these seven farms were analyzed for evolutionary relatedness (by DNA sequencing of the Salmonella genes fimA, manB, and mdh), antibiotic resistance profiles, and the presence of bla_CMY-2, a beta-lactamase gene associated with resistance to cephalosporins. Our data indicate that (i) resistance to ceftriaxone and ceftiofur was highly correlated with the presence of bla_CMY-2; (ii) ceftiofur-resistant Salmonella strains were geographically widespread, as shown by their isolation from farms located throughout New York State; (iii) ceftiofur-resistant Salmonella strains isolated from farms represent multiple distinct subtypes and evolutionary lineages, as determined by serotyping, DNA sequence typing, and antimicrobial-resistance profiles; and (iv) ceftiofur-resistant Salmonella strains evolved by multiple independent acquisitions of an identical bla_CMY-2 allele and by clonal spread of ceftiofur-resistant subtypes.

This article has been cited by other articles:

• Foley, S. L., Lynne, A. M. (2008). Food animal-associated Salmonella challenges: Pathogenicity and antimicrobial resistance. J ANIM SCI 86: E173-E187 [Abstract] [Full Text]  
• Alcaine, S. D., Soyer, Y., Warnick, L. D., Su, W.-L., Sukhnanand, S., Richards, J., Fortes, E. D., McDonough, P., Root, T. P., Dumas, N. B., Grohn, Y., Wiedmann, M. (2006). Multilocus Sequence Typing Supports the Hypothesis that Cow- and Human-Associated Salmonella Isolates Represent Distinct and Overlapping Populations. Appl. Environ. Microbiol. 72: 7575-7585 [Abstract] [Full Text]  
• Raymond, M. J., Wohrle, R. D., Call, D. R. (2006). Assessment and promotion of judicious antibiotic use on dairy farms in Washington State.. J DAIRY SCI 89: 3228-3240 [Abstract] [Full Text]  
• Harbottle, H., White, D. G., McDermott, P. F., Walker, R. D., Zhao, S. (2006). Comparison of Multilocus Sequence Typing, Pulsed-Field Gel Electrophoresis, and Antimicrobial Susceptibility Typing for Characterization of Salmonella enterica Serotype Newport Isolates.. J. Clin. Microbiol. 44: 2449-2457 [Abstract] [Full Text]