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United States Department of Agriculture

Agricultural Research Service

Research Project: EPIDEMIOLOGY, ECOLOGY, AND MOLECULAR GENETICS OF ANTIMICROBIAL RESISTANCE IN PATHOGENIC AND COMMENSAL BACTERIA FROM FOOD ANIMALS Title: Comparison of Campylobacter species Using flaA Short Variable Region DNA Sequence Analysis

Authors
item Cray, Paula
item Plumblee, Jodie

Submitted to: American Society for Microbiology Conference
Publication Type: Abstract Only
Publication Acceptance Date: March 5, 2010
Publication Date: May 23, 2010
Citation: Cray, P.J., Plumblee, J. 2010. Comparison of Campylobacter species Using flaA Short Variable Region DNA Sequence Analysis. American Society for Microbiology Conference. May 23-27, 2010. San Diego, CA. Z-968.

Technical Abstract: Background: Although the relative rates of Campylobacter infections have been declining in the U.S. over the last decade, Campylobacter species continue to be one of the primary bacterial agents responsible for gastroenteritis worldwide. Infections are usually considered foodborne as Campylobacter is a commensal organism found in all food animals. Transmission routes between animals and humans, however, are not fully understood. Thus, the ability to track particular subtypes and epidemiological information is crucial. Materials and Methods: Using flaA Short Variable Region (SVR) DNA sequencing and antimicrobial susceptibility testing, Campylobacter isolates from broiler rinses were speciated and analyzed from the National Antimicrobial Resistance Monitoring System for 2004 (n= 624) and 2008 (n=99). Results: Species distribution was similar for both years (approximately 27.0% of the isolates were C. coli and 73.0% were C. jejuni). From the 339 base pair SVR, 143 and 42 unique sequence alleles were seen in 2004 and 2008, respectively; 14 from 2008 were not seen in 2004. Individual subtypes based on the SVR sequence were represented by as many as 78 isolates or as few as one. No correlation was seen between SVR sequence and species identification as some alleles were consistently represented by only one species while others were distributed between species. Collectively 50.3% of the subtypes were represented by only one isolate. When analyzed geographically, the majority of unique alleles (64.9%) came from only one region of the U.S. Interestingly, three subtypes from 2004 (n=193 isolates), were not found in the Western U.S. Conversely, one subtype seen in both years was only found in isolates from the Western U.S. Overall, while resistance to the quinolones and macrolides was not statistically different between 2004 and 2008, it was not equally distributed among the geographic regions. Conclusions: The use of flaA SVR sequencing is useful in tracking Campylobacter subtypes and showed that some clusters appear to be geographically diverse while others are not.

Last Modified: 10/25/2014