Antimicrobial-drug Susceptibility of Human and Animal Salmonella Typhimurium, Minnesota, 1997–2003

Acute Disease Investigation and Control Section, Minnesota Department of Health, Minneapolis, Minnesota 55164-0975, USA.
Emerging infectious diseases (Impact Factor: 6.75). 01/2006; 11(12):1899-906. DOI: 10.3201/eid1112.050158
Source: PubMed

ABSTRACT We compared antimicrobial resistance phenotypes and pulsed-field gel electrophoresis (PFGE) subtypes of 1,028 human and 716 animal Salmonella enterica serotype Typhimurium isolates from Minnesota from 1997 to 2003. Overall, 29% of human isolates were multidrug resistant. Predominant phenotypes included resistance to ampicillin, chloramphenicol or kanamycin, streptomycin, sulfisoxazole, and tetracycline (ACSSuT or AKSSuT). Most human multidrug-resistant isolates belonged to PFGE clonal group A, characterized by ACSSuT resistance (64%), or clonal group B, characterized by AKSSuT resistance (19%). Most animal isolates were from cattle (n = 358) or swine (n = 251). Eighty-one percent were multidrug resistant; of these, 54% were at least resistance phenotype ACSSuT, and 43% were at least AKSSuT. More than 80% of multidrug-resistant isolates had a clonal group A or B subtype. Resistance to ceftriaxone and nalidixic acid increased, primarily among clonal group A/ACSSuT isolates. Clonal group B/AKSSuT isolates decreased over time. These data support the hypothesis that food animals are the primary reservoir of multidrug-resistant S. Typhimurium.

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    • "An additional challenge for human health is the emergence of multi-antimicrobial resistant (AR) Salmonella strains and the subsequent spread of the AR clones [9]. Pigs and other domestic species are recognized as a primary reservoir of multi-AR bacteria, usually associated with the selective pressure exerted by antimicrobial treatments [10]. The emergence and spread of multi-AR Salmonella are often related to both the acquisition and the fixation of bacterial mobile genetic elements such as plasmids, transposons or integrons [11]. "
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    ABSTRACT: Salmonellosis is a major worldwide zoonosis, and Salmonella-infected finishing pigs are considered one of the major sources of human infections in developed countries. Baseline studies on salmonellosis prevalence in fattening pigs in Europe are based on direct pathogen isolation from mesenteric lymph nodes (MLN). This procedure is considered the most reliable for diagnosing salmonellosis in apparently healthy pigs. The presence of simultaneous infections by different Salmonella strains in the same animal has never been reported and could have important epidemiological implications. Fourteen finishing pigs belonging to 14 farms that showed high salmonellosis prevalence and a variety of circulating Salmonella strains, were found infected by Salmonella spp, and 7 of them were simultaneously infected with strains of 2 or 3 different serotypes. Typhimurium isolates showing resistance to several antimicrobials and carrying mobile integrons were the most frequently identified in the colonized MLN. Four animals were found infected by Salmonella spp. of a single serotype (Rissen or Derby) but showing 2 or 3 different antimicrobial resistance profiles, without evidence of mobile genetic element exchange in vivo. This is the first report clearly demonstrating that pigs naturally infected by Salmonella may harbour different Salmonella strains simultaneously. This may have implications in the interpretation of results from baseline studies, and also help to better understand human salmonellosis outbreaks and the horizontal transmission of antimicrobial resistance genes.
    BMC Veterinary Research 03/2014; 10(1):59. DOI:10.1186/1746-6148-10-59 · 1.78 Impact Factor
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    • "Pattern AMXRDOXRCEFR was the most prevalent (17.3%) while CAZRCEFRAMKRChlRGENR, CIPRCAZRCEFRSXTRChlRGENR, CEFRCAZRSXTROFXRAMKRChlR, and AMXRChlR were the least common (1.3%) (Table 3). The frequency of isolation of S. Typhimurium DT104 in food-animals worldwide has increased because of its spread and recent reports (20,34) on changes in resistance phenotype, or phage-type in MDR S. Typhimurium underscores the need for continuous monitoring of susceptibility pattern of S. Typhimurium from food-animals. Our findings of high levels of multidrug-resistant Salmonella in slaughtered cattle and pigs and in the environment highlight the potential risk of S. Typhimurium DT 104, with multidrug resistance becoming established in Cameroon. "
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    Journal of Health Population and Nutrition 10/2009; 27(5):612-8. DOI:10.3329/jhpn.v27i5.3637 · 1.04 Impact Factor
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    Foodborne Pathogens and Disease 02/2007; 4(4):551-63. DOI:10.1089/fpd.2007.0014 · 1.91 Impact Factor
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