肉食鸡中产超广谱β-内酰胺酶的耐药性大肠杆菌的检测和分析

Detection of extended spectrum β-lactamase producing E. coli from broiler chickens

摘要:

[目的] 本文对山东某屠宰场的肉食鸡内脏中的大肠杆菌进行了β-内酰胺类抗生素的耐药性监测和分析。[方法] 从屠宰场的肉食鸡中获取内脏样品，处理并筛选得到对β-内酰胺类耐药的大肠杆菌。通过抑菌圈法对细菌耐药性进行分析。提取细菌DNA，进行系统发育亚型分析。检测并鉴定菌株中β-内酰胺酶基因和整合子的结构，并进行了接合转移实验。[结果] 检测到对3种及以上的β-内酰胺类药物同时具有耐药性的大肠杆菌占总菌的80%以上。编码A类β-内酰胺酶的bla_TEM和bla_CTX-M耐药基因存在率较高，分别为86.7%和81%，但仅bla_CTX-M与β-内酰胺类药物的耐药性呈现显著相关性。B₁和D₂亚型的大肠杆菌中β-内酰胺耐药基因的检出率较高，并且显著增强了大肠杆菌对β-内酰胺类药物的耐药性，而A₀和A₁亚型菌株对β-内酰胺类药物较敏感。尽管整合子在大肠杆菌中普遍存在，但它们伴随β-内酰胺酶基因转移到受体菌的比例很低，说明二者之间的相关性较低。[结论] 本文结果显示肉鸡源大肠杆菌对β-内酰胺类药物的耐药程度较高，多重耐药情况普遍存在。本文明确了大肠杆菌中β-内酰胺类抗生素的耐药性与系统发育之间的联系，为肉鸡源大肠杆菌中β-内酰胺耐药性的流行监测提供参考依据。

Abstract:

[Objective] We detected and analyzed β-lactam resistance in E. coli in broiler chickens in Shandong province. [Methods] The viscera samples were obtained from broiler chickens in the slaughterhouse. We screened β-lactam resistant E. coli, used the disk diffusion assay to determine antimicrobial-resistance, extracted bacterial DNA, conducted phylogenetic and biochemical assays, identified β-lactam-resistance genes and the structure of integrons and performed conjugation assays. [Results] More than 80% isolates were resistant to 3 or more β-lactams. The bla_TEM and bla_CTX-M resistance genes encoding class A β-lactamases have a higher rate, 86.7% and 81%, respectively, but only bla_CTX-M and β-lactam resistance showed a significant correlation. The rate of β-lactam resistance genes in B₁ and D₂ subtypes of E. coli was higher, and the resistance was significantly enhanced, while the A₀ and A₁ subtypes were more sensitive. Although integrons were commonly detected in E. coli, their correlation with β-lactamase genes is low. [Conclusion] The results show that broiler-derived E. coli has highly resistant to β-lactams, and multi-drug resistance is widespread. The relationship between the resistance of β-lactams and the phylogeny in E. coli is clarified, and it provides a reference for the epidemiological surveillance of β-lactam resistance in E. coli from broilers.