99D-9 |
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S. ZHAO1, S. L. Friedman1, C. Kiessling2, S. Qaiyumi1, S. L. Ayers1, R. Singh1, and D. G. White1. (1) Office of Research, U.S. FDA-Center for Veterinary Medicine, Div. of Animal & Food Microbiology, 8401 Muirkirk Rd., Laurel, MD 20708, (2) Office of Regulatory Affairs, U.S. Food & Drug Administration, 6th & Kipling St., Bldg. 20, PO Box 25087, Denver, CO 80225-0087 Foodborne diseases caused by non-typhoid Salmonella represent an important public health problem worldwide. Recent studies have shown that many Salmonella isolated from domestic food products are resistant to antimicrobials commonly used in human and veterinary medicine. The emergence of antimicrobial resistance among Salmonella can potentially compromise the treatment of Salmonella infections. Yet, little is known regarding antimicrobial resistance of Salmonella recovered from imported foods coming into the United States. In this study, 208 Salmonella isolates representing 66 serotypes from foods imported from 31 countries/regions in 2001 by the U.S. Food and Drug Administration field laboratories were tested for susceptibility to 17 antimicrobials of human and veterinary significance. Twenty-two (10.6%) isolates were resistant to at least one antimicrobial, and seven (3.4%) to three or more antimicrobials. Most isolates (n=17) were resistant to tetracycline followed by sulfamethoxazole (n=10), streptomycin (n=9), and nalidixic acid (n=7). Four isolates were also resistant to chloramphenicol and trimethoprim/sulfamethoxazole, respectively. One isolate (S. Schwarzengrund) from squid imported from Taiwan exhibited resistance to 8 antimicrobials including ampicillin, chloramphenicol, gentamicin, kanamycin, nalidixic acid, sulfamethoxazole, tetracycline, and trimethoprim/sulfamethoxazole. Six isolates (S. Bareilly, S. Derby, S. Ohio and S. Schwarzengrund) also contained class 1 integrons that carried several different gene cassettes including antimicrobial dhfrI, dhfrIII, dhfrXII, aadA, and pse-1, which confer resistance to trimethoprim/sulfamethoxazole, streptomycin and ampicillin, respectively. Compared to Salmonella antimicrobial susceptibility profiles isolated from imported food in the year 2000, resistance has slightly increased (in 2000, 8% resistance to at least one antimicrobial and 2.7% resistance to three or more antimicrobials). This study indicates that it is imperative to continue to monitor the prevalence and antimicrobial susceptibility profiles of foodborne zoonotic bacterial pathogens in foods entering the United States.
Session 99D, Food Microbiology: General
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