title: Prevalence and characterization of Salmonella serovars in retail meats of marketplace in Shaanxi, China.
abstract: A total of 764 retail meat including 515 chicken, 91 pork, 78 beef and 80 lamb samples were collected in Shaanxi Province of China in 2007-2008 to determine the prevalence of Salmonella. The isolates were characterized using serotyping, antimicrobial susceptibility testing, and the presence of bla(CMY-2) and bla(TEM) and class I integrons. Selective serovars were further subtyped using PFGE. Approximately 54% (276) of chicken, 31% (28) of pork, 17% (13) of beef and 20% (16) of lamb samples were positive of Salmonella. Among 24 serovars identified, Enteritidis (31.5%) was most common, followed by Typhimurium (13.4%), Shubra (10.0%), Indiana (9.7%), Derby (9.5%) and Djugu (7.0%). Nearly 80% of the isolates (283) were resistant to at least one antimicrobial, and 53% (191) to more than three antimicrobials. Resistance was most frequently observed to sulfamethoxazole (67%), to trimethoprim/sulfamethoxazole (58%) and to tetracycline (56%). Furthermore, many isolates were resistant to nalidixic acid (35%), ciprofloxacin (21%) and ceftriaxone (16%). Most isolates of Shubra (89%) and Indiana (88%) were resistant to > or = 9 antimicrobials, compared to only 11% of Enteritidis and 9% of Infantis that showed similar resistance. Class I integrons were detected in 10% of the isolates, and contained aadA, tetR, dhfr, bla(PSE-1), bla(DHA-1) and bla(VEB-1) gene cassettes alone or various combinations. Ceftriaxone- and/or cefoperazone-resistant isolates (n=62) carried bla(TEM) (51.6%) and/or bla(CMY-2) (56.5%). A total of 116 PFGE patterns were generated among 210 selected isolates. Our findings indicated that Salmonella contamination was common in retail meats, and that the Salmonella isolates were phenotypically and genetically diverse. Additionally, many Salmonella isolates were resistant to multiple antimicrobials.
authors.affiliation: Northwest A&F University, Shaanxi 712100, China.
authors.forename: Baowei
authors.initials: B
authors.lastname: Yang
authors.forename: Dong
authors.initials: D
authors.lastname: Qu
authors.forename: Xiuli
authors.initials: X
authors.lastname: Zhang
authors.forename: Jinling
authors.initials: J
authors.lastname: Shen
authors.forename: Shenghui
authors.initials: S
authors.lastname: Cui
authors.forename: Ying
authors.initials: Y
authors.lastname: Shi
authors.forename: Meili
authors.initials: M
authors.lastname: Xi
authors.forename: Min
authors.initials: M
authors.lastname: Sheng
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhi
authors.forename: Jianghong
authors.initials: J
authors.lastname: Meng
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents; D001483:Base Sequence; D002417:Cattle; D002645:Chickens; D002681:China; D003132:Commerce; D024901:Drug Resistance, Multiple, Bacterial; D016521:Electrophoresis, Gel, Pulsed-Field / Q000379:methods; D005516:Food Microbiology; D032023:Integrons; D008460:Meat / Q000382:microbiology*; D015995:Prevalence; D012475:Salmonella / Q000145:classification / Q000235:genetics / Q000302:isolation & purification*; D012703:Serotyping / Q000379:methods; D012756:Sheep; D013552:Swine; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001618:beta-Lactamases