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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

Location: Bacterial Epidemiology and Antimicrobial Resistance

Title: Prevalence of antimicrobial resistance in Salmonella serotype Hadar isolated from humans, retail meat, and food animals at slaughter, United States, NARMS 1996-2008

Authors
item Rickert, R -
item Haro, Jovita
item Tong, E -
item Medalla, F -
item Karp, B -
item Barzilay, E -
item Zhao, S -
item Cray, Paula

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: June 8, 2010
Publication Date: June 8, 2010
Citation: Rickert, R., Haro, J.H., Tong, E., Medalla, F., Karp, B., Barzilay, E., Zhao, S., Cray, P.J. 2010. Prevalence of antimicrobial resistance in Salmonella serotype Hadar isolated from humans, retail meat, and food animals at slaughter, United States, NARMS 1996-2008. Conference on Antimicrobial Resistance in Zoonotic Bacteria and Foodborne Pathogens in Animals, Humans and the Environment. June 8-11, 2010. Toronto, Canada. A107

Technical Abstract: Background Non-Typhi Salmonella (NTS) is a leading cause of bacterial gastroenteritis in the United States. Although most infections are self-limited, antibiotic treatment is essential for severe illness. Use of antimicrobial agents in food animals contributes to resistance in NTS. Multidrug resistant (MDR) Salmonella serotype Hadar has been isolated from poultry and humans worldwide. In the United States, an increase in Salmonella Hadar isolates from ground turkey has been observed since 2005; Hadar was the most common serotype isolated from ground turkey and turkey at slaughter in 2007 and 2008. Methods The National Antimicrobial Resistance Monitoring System (NARMS) conducts susceptibility testing on isolates from humans, retail meat and food-producing animals at slaughter. MICs for 15 antimicrobial agents were determined by broth microdilution and interpreted using CLSI criteria when available. We describe resistance in Salmonella Hadar isolates from humans (1996-2008), retail meat (2002-2008), and food animals at slaughter (1997-2008). Results Of 264 human Salmonella Hadar isolates tested, 93.1% were resistant to one or more agents, and 22.0% were MDR (resistant to = 3 CLSI classes). Resistance was most prevalent to tetracycline (91.7%), streptomycin (73.1%), and ampicillin (19.3%). Quinolone resistance was detected in 3.4% of isolates. All isolates were susceptible to ceftriaxone. There were 220 Salmonella Hadar isolates from retail meat: 191 ground turkey (GT), 28 chicken breast (CB), and 1 pork chop (PC). Of the 220 isolates tested, resistance was most prevalent to tetracycline (95.0%), streptomycin (90%), and ampicillin (38.6%). There was no other resistance in CB and PC isolates; however quinolone resistance was detected in 1.6% of GT isolates. Among all Salmonella Hadar isolates from retail meat, 41.8% were MDR. There were 1276 Salmonella Hadar isolates from food animals at slaughter: 767 turkey, 433 chicken, 51 swine, and 25 cattle. Of the 1276 isolates tested, resistance was most prevalent to tetracycline (91.1%), streptomycin (65.0%), sulfonamides (14.3%), and ampicillin (13.4%). Quinolone resistance was observed in 3.4% of turkey isolates. Resistance to ceftriaxone was present in 1.4% of chicken and 0.4% of turkey isolates. Among all Salmonella Hadar isolates from food animals at slaughter, 19.4% were MDR. Conclusions At least 19% of Salmonella Hadar isolates from all sources-human, food, and animal-were MDR. Tetracycline, streptomycin, and ampicillin resistance was prevalent among the three sources. Although rare, quinolone resistance was observed in all three sources, and ceftriaxone resistance was observed in chicken and turkey at slaughter. Results of this study indicate the widespread occurrence and distribution of MDR Salmonella Hadar in poultry, which could be a potential source of human MDR Salmonella Hadar infections.

Last Modified: 7/24/2014
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