Phenotypic and genetic characterization of antimicrobial resistance in Salmonella serovars isolated from retail meats in Alberta, Canada.

This study determined the prevalence of Salmonella serovars, antimicrobial resistance (AMR) and resistance genes in Salmonella isolated from retail meats purchased in Alberta, Canada. Samples were collected during one year period (May 2007-April 2008) on weekly basis from 19 census divisions in Alberta. A total of 564 samples including chicken (n = 206), turkey (n = 91), beef (n = 134) and pork (n = 133) were purchased. Salmonella were recovered from chicken (40%), turkey (27%) and pork (2%) samples and was not found in ground beef. A total of 21, 8, and 3 different serovars were recovered from chicken, turkey and pork meats, respectively. Salmonella Hadar was most common in chicken whereas S. Heidelberg was common in turkey meat. Overall 29% (32/110) of isolates were susceptible to tested antimicrobials and resistance to ciprofloxacin, amikacin and nalidixic acid was not found in any isolate. Multiresistance (≥2 antimicrobials) was found in 56% of isolates. Resistance to amoxicillin-clavulanic acid (AMC), ceftiofur (TIO), and ceftriaxone (CRO) was found in about 21% of chicken and 25% of turkey isolates. Resistance to either of tetracycline (TET), streptomycin (STR) or ampicillin (AMP) was unconditionally associated with S. Hadar but resistance to either of TET, AMP, AMC, TIO, CRO or cefoxitin was associated with S. Heidelberg. The strA/B (42% isolates), tet(A) (28% isolates), bla(CMY-2) (21% isolates) and bla(TEM) (17% isolates) were the most common resistance genes found. The bla(CMY-2) and bla(TEM) genes were unconditionally associated with S. Heidelberg; tet(A) and strA/B with S. Hadar and tet(B) gene with S. Kentucky. The strA/B genes were not associated with S. Heidelberg. Our data suggests that the prevalence of Salmonella serovars varied by the meat type and that AMR and resistance genes varied by the Salmonella serovars.

Aslam M ，Checkley S ，Avery B ，Chalmers G ，Bohaychuk V ，Gensler G ，Reid-Smith R ，Boerlin P ... -  《-》

Antimicrobial resistance and resistance genes in Escherichia coli isolated from retail meat purchased in Alberta, Canada.

Sheikh AA ，Checkley S ，Avery B ，Chalmers G ，Bohaychuk V ，Boerlin P ，Reid-Smith R ，Aslam M ... -  《-》

Antimicrobial resistance and genetic relatedness among Salmonella from retail foods of animal origin: NARMS retail meat surveillance.

Zhao S ，McDermott PF ，Friedman S ，Abbott J ，Ayers S ，Glenn A ，Hall-Robinson E ，Hubert SK ，Harbottle H ，Walker RD ，Chiller TM ，White DG ... -  《Foodborne Pathogens and Disease》

Prevalence and characterization of Salmonella serovars in retail meats of marketplace in Shaanxi, China.

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.

Yang B ，Qu D ，Zhang X ，Shen J ，Cui S ，Shi Y ，Xi M ，Sheng M ，Zhi S ，Meng J ... -  《-》

Antimicrobial resistance in Salmonella enterica serovar Heidelberg isolates from retail meats, including poultry, from 2002 to 2006.

Zhao S ，White DG ，Friedman SL ，Glenn A ，Blickenstaff K ，Ayers SL ，Abbott JW ，Hall-Robinson E ，McDermott PF ... -  《-》