Identification, Typing, and Drug Resistance Analysis of Escherichia coli in Two Different Types of Broiler Farms in Hebei Province

SIMPLE SUMMARY: Antibiotic resistance is a global health crisis faced by humanity. In response to this crisis, in 2018, China released the National Pilot Work Program for Action to Reduce the Use of Veterinary Antimicrobial Drugs. Pilot work to reduce the use of antimicrobial drugs was carried out on livestock and poultry scale farms across the country, and the farms implementing the reduction in antimicrobial drug use were accepted as meeting the standards by the “Evaluation Standards and Methods for Reducing the Use of Veterinary Antimicrobial Drugs on Livestock and Poultry Farms”. To evaluate the effect of antimicrobial drug reduction on antibiotic resistance, we selected six broiler farms in Hebei Province for the first time, four of which implemented antimicrobial drug reduction and passed national acceptance (SFs), and the other two did not implement antimicrobial drug reduction (NSFs). By collecting cloacal swabs from healthy broilers, isolating and characterizing Escherichia coli (E. coli), and determining their resistance phenotypes, resistance profiles, and genotypes to 16 antimicrobial drugs, as well as ST typing of the isolates, we compared the differences in resistance and the genetic evolutionary relationships of two different types of broiler farms in Hebei Province, China. ABSTRACT: Hebei Province is an important area for breeding broiler chickens in China, but the antimicrobial resistance and prevalence of Escherichia coli (E. coli) are still unclear. A total of 180 cloacal samples from broiler farms in Hebei Province were collected and used for the isolation and identification of E. coli. The isolates were subjected to resistance phenotyping, resistance profiling, and genotyping, and some multiresistant strains were subjected to multilocus sequence typing (MLST). The results showed that 175 strains were isolated. Among both types of broiler farms, the ampicillin resistance rate was the highest, and the meropenem resistance rate was the lowest. Serious multiresistance was present in both types of broiler farms. Thirty strains of multidrug-resistant E. coli were typed by MLST to obtain a total of 18 ST types, with ST10 being the most prevalent. This study was to simply analyze the antimicrobial resistance and prevalence of E. coli in broiler chickens in Hebei Province after the implementation of the pilot work program of action to reduce the use of veterinary antimicrobials in standard farms (SFs) and nonstandard farms (NSFs). This study will provide a research basis and data support for the prevention and control of E. coli in Hebei.