巴西南部城市鸡胴体和人感染中产 CMY-2 型β-内酰胺酶大肠埃希菌的特征。
Characterization of CMY-2-type beta-lactamase-producing Escherichia coli isolated from chicken carcasses and human infection in a city of South Brazil.
机构信息
Basic and Applied Bacteriology Laboratory, Department of Microbiology, State University of Londrina (UEL), Londrina, PR, Brazil.
Bacterial Molecular Biology Laboratory, Department of Genetics, Evolution and Bioagents, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil.
出版信息
BMC Microbiol. 2019 Jul 30;19(1):174. doi: 10.1186/s12866-019-1550-3.
BACKGROUND
Food-producing animals, mainly poultry, have been associated with the maintenance and dissemination of antibiotic-resistant bacteria, such as plasmid-mediated AmpC (pAmpC)-producing Enterobacteriaceae, to humans, thus impacting food safety. Many studies have shown that Escherichia coli strains isolated from poultry and humans infections share identical cephalosporin resistance, suggesting that transmission of resistance from poultry meat to humans may occur. The aim of this study was to characterize pAmpC-producing E. coli strains isolated from chicken carcasses and human infection in a restrict area and to determine their antimicrobial resistance profiles, and molecular type by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE).
RESULTS
A total of 14 pAmpC-producing E. coli strains were isolated, including eight strains from chicken carcasses and six strains from human infections (from urine, tissue and secretion). The bla gene was identified in all pAmpC-producing E. coli strains by polymerase chain reaction (PCR) and DNA sequencing. High percentages of strains resistant to tetracycline, nalidixic acid and sulfamethoxazole-trimethoprim (78-92%) were detected, all of which were considered multidrug-resistant. Among the non-beta-lactam resistance genes, the majority of the strains showed tetA, tetB, sulI and sulII. No strain was considered an extended-spectrum beta-lactamases (ESBL) producer, and the bla gene was found in 2 strains isolated from human infection. Six strains from chicken carcasses and four strains from humans infections were linked to an ISEcp1-like element. Through MLST, 11 sequence types were found. Three strains isolated from human infection and one strain isolated from chicken carcasses belonged to the same sequence type (ST354). However, considerable heterogeneity between the strains from chicken carcasses and humans was confirmed by PFGE analysis.
CONCLUSION
This study showed the prevalence of E. coli strains producing bla linked to ISEcp1 that were present in both chickens and humans in a restricted area. Our results also suggest the presence of a highly diverse strains that harbor pAmpC, indicating no clonal dissemination. Therefore, continuous monitoring and comparative analyses of resistant bacteria from humans and food-producing animals are needed.
背景
食品生产动物（主要是家禽）与抗生素耐药菌（如质粒介导的 AmpC（pAmpC）-产生肠杆菌科）的维持和传播有关，从而影响食品安全。许多研究表明，从家禽和人类感染中分离出的大肠杆菌菌株具有相同的头孢菌素耐药性，这表明耐药性可能从禽肉传播给人类。本研究的目的是描述从限制区域的鸡胴体和人类感染中分离出的产质粒介导 AmpC（pAmpC）的大肠杆菌菌株的特征，并通过多位点序列分型（MLST）和脉冲场凝胶电泳（PFGE）确定其抗菌药物耐药谱和分子类型。
结果
共分离出 14 株产质粒介导 AmpC 的大肠杆菌，其中 8 株来自鸡胴体，6 株来自人类感染（来自尿液、组织和分泌物）。通过聚合酶链反应（PCR）和 DNA 测序鉴定所有产质粒介导 AmpC 的大肠杆菌菌株均存在 bla 基因。发现高比例的菌株对四环素、萘啶酸和磺胺甲恶唑-甲氧苄啶（78-92%）耐药，均被认为是多药耐药菌。在非β-内酰胺类耐药基因中，大多数菌株表现出 tetA、tetB、sulI 和 sulII。没有菌株被认为是超广谱β-内酰胺酶（ESBL）产生者，在从人类感染中分离出的 2 株菌中发现了 bla 基因。6 株来自鸡胴体，4 株来自人类感染的菌株与 ISEcp1 样元件有关。通过 MLST，发现了 11 种序列类型。从人类感染中分离出的 3 株和从鸡胴体中分离出的 1 株属于同一序列类型（ST354）。然而，通过 PFGE 分析证实了来自鸡胴体和人类的菌株之间存在相当大的异质性。
结论
本研究表明，在一个限制区域内，鸡和人类都存在携带 ISEcp1 并产生 bla 的大肠杆菌菌株。我们的结果还表明，存在高度多样化的产质粒介导 AmpC 的菌株，表明没有克隆传播。因此，需要对来自人类和食品生产动物的耐药菌进行持续监测和比较分析。
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