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Báo cáo khoa học: "Prevalence and characterization of plasmids carrying sulfonamide resistance genes among Escherichia coli from pigs, pig carcasses and human"

Tuyển tập các báo cáo nghiên cứu về bệnh học thý y được đăng trên tạp chí Acta Veterinaria Scandinavica cung cấp cho các bạn kiến thức về bệnh thú yđề tài: Prevalence and characterization of plasmids carrying sulfonamide resistance genes among Escherichia coli from pigs, pig carcasses and human. | Wu et al. Acta Veterinaria Scandinavica 2010 52 47 http www.actavetscand.eom content 52 1 47 AVS ACTAVETERINARIA SCANDINAVICA RESEARCH Open Access Prevalence and characterization of plasmids carrying sulfonamide resistance genes among Escherichia coli from pigs pig carcasses and human Shuyu Wu1 2 4 Anders Dalsgaard2 Anette M Hammerum3 Lone J Porsbo1 Lars B Jensen1 Abstract Background Sulfonamide resistance is very common in Escherichia coli. The aim of this study was to characterize plasmids carrying sulfonamide resistance genes sull sul2 and sul3 in E. coli isolated from pigs and humans with a specific objective to assess the genetic diversity of plasmids involved in the mobility of sul genes. Methods A total of 501 E. coli isolates from pig feces pig carcasses and human stools were tested for their susceptibility to selected antimicrobial. Multiplex PCR was conducted to detect the presence of three sul genes among the sulfonamide-resistant E. coli isolates. Fifty-seven sulfonamide-resistant E. coli were selected based on presence of sul resistance genes and subjected to conjugation and or transformation experiments. S1 nuclease digestion followed by pulsed-field gel electrophoresis was used to visualize and determine the size of plasmids. Plasmids carrying sul genes were characterized by PCR-based replicon typing to allow a comparison of the types of sul genes the reservoir and plasmid present. Results A total of 109 501 isolates exhibited sulfonamide resistance. The relative prevalences of sul genes from the three reservoirs pigs pig carcasses and humans were 65 45 and 12 for sul2 sull and sul3 respectively. Transfer of resistance through conjugation was observed in 42 57 isolates. Resistances to streptomycin ampicillin and trimethoprim were co-transferred in most strains. Class 1 integrons were present in 80 of sull-carrying plasmids and 100 of sul3-carrying plasmids but only in 5 of sul2-carrying plasmids. The sul plasmids ranged from 33 to 160-kb in size and