Poppe C, Ziebell K, Martin L, Allen K
Health Canada, Population and Public Health Branch, Laboratory for Foodborne Zoonoses, Guelph, Ontario.
Microb Drug Resist. 2002 Summer;8(2):107-22. doi: 10.1089/107662902760190653.
Multiresistant Salmonella enterica subspecies enterica serovar Typhimurium definitive type 104 (S. Typhimurium DT104 or DT104) bacteria are important pathogens in animals and humans. DT104 isolates are often called pentaresistant strains that spread clonally. The purpose of this study was to determine phenotypic, genotypic, and epidemiologic characteristics of 175 S. Typhimurium DT104 strains isolated from food-producing animals in Canada. More than 90% of the isolates were resistant to ampicillin (Amp), chloramphenicol (Chl), florfenicol (Flo), sulfisoxazole (Sul), and tetracycline (Tet), 53% of the isolates were additionally resistant to spectinomycin (Spc) and streptomycin (Str), and 28% to kanamycin (Kan) and neomycin (Neo). Sixty-one percent of the strains harbored a single 60-MDa plasmid, 21% contained 60- and 2.0-MDa plasmids, and 4% had 60, 4.6- and 2.0-MDa plasmids. Resistance to Kan and Neo was encoded by the aminoglycoside aphA-1 gene on 2.0-MDa plasmids, whereas resistance to trimethoprim (Tmp) and Sul was encoded by the dhfrIb gene on 4.6-MDa plasmids. Polymerase chain reactions (PCR) showed the presence of integrons with the ant (3")-Ia aminoglycoside adenyltransferase and the bla(PSE-1) beta-lactamase gene cassettes, and the presence of the flost gene in all but one strain resistant to Spc and Str, Amp, and Chl and Flo, respectively. DT104 isolates from cattle at six feedlots represented a separate clone; they were sensitive to Str and Spc and lacked the ant (3")-Ia gene. Pulsed-field gel electrophoresis (PFGE) using Bln I, Spe I, and Xba I resulted in 15, 12, and 8 PFGE patterns, respectively. In summary, we observed considerable diversity in phenotypic, genotypic, and epidemiological characteristics among the DT104 isolates.
多重耐药性肠炎沙门氏菌肠道亚种鼠伤寒血清型104(鼠伤寒沙门氏菌DT104或DT104)细菌是人和动物中的重要病原体。DT104分离株通常被称为以克隆方式传播的五重耐药菌株。本研究的目的是确定从加拿大产食用动物中分离出的175株鼠伤寒沙门氏菌DT104菌株的表型、基因型和流行病学特征。超过90%的分离株对氨苄西林(Amp)、氯霉素(Chl)、氟苯尼考(Flo)、磺胺异恶唑(Sul)和四环素(Tet)耐药,53%的分离株还对壮观霉素(Spc)和链霉素(Str)耐药,28%对卡那霉素(Kan)和新霉素(Neo)耐药。61%的菌株携带一个60-MDa质粒,21%含有60-MDa和2.0-MDa质粒,4%有60-MDa、4.6-MDa和2.0-MDa质粒。对Kan和Neo的耐药性由2.0-MDa质粒上的氨基糖苷aphA-1基因编码,而对甲氧苄啶(Tmp)和Sul的耐药性由4.6-MDa质粒上的dhfrIb基因编码。聚合酶链反应(PCR)显示存在带有ant(3")-Ia氨基糖苷腺苷转移酶和bla(PSE-1)β-内酰胺酶基因盒的整合子,并且除了一株分别对Spc和Str、Amp以及Chl和Flo耐药的菌株外,所有菌株中均存在flost基因。来自六个饲养场的牛的DT104分离株代表一个单独的克隆;它们对Str和Spc敏感且缺乏ant(3")-Ia基因。使用Bln I、Spe I和Xba I进行脉冲场凝胶电泳(PFGE)分别产生了15、12和8种PFGE图谱。总之,我们观察到DT104分离株在表型、基因型和流行病学特征方面存在相当大的差异。