Vounba Passoret, Arsenault Julie, Bada-Alambédji Rianatou, Fairbrother John Morris
Department of Pathology and Microbiology, Faculty of Veterinary Medicine, Université de Montréal, the Swine and Poultry Infectious Diseases Research Centre (CRIPA) and the Research Group on Zoonoses and Public Health (GREZOSP), St-Hyacinthe, Quebec, Canada.
Department of Public Health and Environment, Ecole Inter-Etats des Sciences et Médecine Vétérinaires (EISMV), de Dakar, Senegal.
BMC Vet Res. 2019 Apr 4;15(1):106. doi: 10.1186/s12917-019-1849-1.
Antimicrobial resistance (AMR) in food-producing animals is a global public health issue. This study investigated AMR and virulence profiles of E. coli isolated from healthy chickens in Vietnam. E. coli were isolated from fecal samples collected in five chicken farms located in the provinces of Hoa Binh, Thai Nguyen and Bac Giang in the North of Vietnam. These isolates were examined by disk diffusion for their AMR, PCR for virulence and AMR genes, pulsed-field gel electrophoresis for relatedness between bla/bla-positive isolates, electroporation for transferability of bla or bla genes and sequencing for mutations responsible for ciprofloxacin resistance.
Up to 99% of indicator isolates were multidrug resistant. Resistance to third-generation cephalosporins (3GC) was encoded by both bla and bla genes; bla genes being of genotypes bla and , whereas ciprofloxacin resistance was due to mutations in the gyrA and parC genes. Some isolates originating from farms located in different provinces of Vietnam were found to be closely related, suggesting they may have been disseminated from a same source of contamination. Plasmids may also have played a role in the diffusion of 3GC-resistance as the bla gene was located on plasmids A/C and I1, and the bla gene variants were carried by I1, FIB, R and HI1. Plasmids carrying the bla/bla genes also co-transferred resistance to other antimicrobials. In addition, isolates potentially capable of infecting humans, of which some produced bla/bla, were identified in this study.
Both clones and plasmids could be involved in the dissemination of 3GC-resistant E. coli within and between chicken farms in Vietnam. These results demonstrate the necessity to monitor AMR and control antimicrobial use in poultry in Vietnam.
食用动物中的抗菌药物耐药性（AMR）是一个全球公共卫生问题。本研究调查了从越南健康鸡中分离出的大肠杆菌的AMR和毒力谱。从位于越南北部和平省、太原省和北江省的五个养鸡场收集的粪便样本中分离出大肠杆菌。通过纸片扩散法检测这些分离株的AMR，通过PCR检测毒力和AMR基因，通过脉冲场凝胶电泳检测bla/bla阳性分离株之间的相关性，通过电穿孔检测bla或bla基因的可转移性，并通过测序检测对环丙沙星耐药的突变。
高达99%的指示分离株对多种药物耐药。对第三代头孢菌素（3GC）的耐药性由bla和bla基因编码；bla基因的基因型为bla和 ，而对环丙沙星的耐药性是由于gyrA和parC基因的突变。发现一些来自越南不同省份养鸡场的分离株密切相关，这表明它们可能来自同一污染源。质粒也可能在3GC耐药性的传播中起作用，因为bla基因位于质粒A/C和I1上，bla基因变体由I1、FIB、R和HI1携带。携带bla/bla基因的质粒也共同转移了对其他抗菌药物的耐药性。此外，本研究中鉴定出了可能感染人类的分离株，其中一些产生bla/bla。
克隆和质粒都可能参与了越南养鸡场内和养鸡场之间耐3GC大肠杆菌的传播。这些结果表明在越南监测AMR和控制家禽抗菌药物使用的必要性。
