Lynne Aaron M, Kaldhone Pravin, David Donna, White David G, Foley Steven L
National Farm Medicine Center, Marshfield Clinic Research Foundation, Marshfield, Wisconsin 54449, USA.
Foodborne Pathog Dis. 2009 Mar;6(2):207-15. doi: 10.1089/fpd.2008.0172.
Fifty-eight Salmonella enterica serovar Heidelberg isolates isolated from food animals were tested for antimicrobial susceptibilities and further characterized for select antimicrobial resistance genes, plasmid carriage, class 1 integrons, and genetic relatedness using pulsed-field gel electrophoresis (PFGE). Seventy-two percent of isolates displayed resistance to at least one of the antimicrobial agents tested, while 24% exhibited resistance to eight or more antimicrobial agents. Resistance was most commonly observed to tetracycline (71%), streptomycin (62%), and kanamycin (52%). Isolates obtained from cattle and swine displayed the highest rates of resistance while isolates from chickens more often displayed susceptibility to the tested antimicrobials. When resistance was detected, a corresponding resistance gene was detected in 97.3% of the isolates. Thirteen percent of the isolates contained class 1 integrons containing at least one resistance gene, most often either the aadA or dhfrA genes, which are often associated with resistance to streptomycin and trimethoprim, respectively. Twenty isolates contained plasmids estimated to be at least 75 kb in size, 17 of which exhibited resistance to five or more antimicrobial agents. Thirty PFGE patterns were generated among the 58 isolates tested using XbaI, indicating extensive heterogeneity among this serotype across different animal origins. Results confirm the presence of multidrug-resistance (MDR) phenotypes among food animal isolates of serovar Heidelberg, especially those obtained from mammalian species. The observed MDR was typically associated with the presence of large plasmids.
对从食用动物中分离出的58株肠炎沙门氏菌海德堡血清型菌株进行了药敏试验，并使用脉冲场凝胶电泳（PFGE）对选定的抗菌耐药基因、质粒携带情况、1类整合子和遗传相关性进行了进一步表征。72%的菌株对至少一种测试抗菌药物耐药，而24%的菌株对八种或更多抗菌药物耐药。最常见的耐药情况是对四环素（71%）、链霉素（62%）和卡那霉素（52%）耐药。从牛和猪分离出的菌株耐药率最高，而从鸡分离出的菌株对测试抗菌药物更常表现出敏感性。当检测到耐药性时，97.3%的菌株中检测到相应的耐药基因。13%的菌株含有1类整合子，其中至少含有一个耐药基因，最常见的是aadA或dhfrA基因，它们分别常与对链霉素和甲氧苄啶的耐药性相关。20株菌株含有估计大小至少为75 kb的质粒，其中17株对五种或更多抗菌药物耐药。使用XbaI对测试的58株菌株产生了30种PFGE图谱，表明该血清型在不同动物来源中存在广泛的异质性。结果证实了海德堡血清型食用动物分离株中存在多重耐药（MDR）表型，尤其是从哺乳动物物种中分离出的菌株。观察到的MDR通常与大质粒的存在有关。
