The prevalence of amphenicol resistance in Escherichia coli isolated from pigs in mainland China from 2000 to 2018: A systematic review and meta-analysis

BACKGROUND: Amphenicols have been widely used in the pig industry in China, leading to varying degrees of drug resistance. METHODS: The systematic review was performed according to PRISMA (Preferred Reported Items for Systematic Reviews and Meta-Analysis) recommendations on studies investigating the prevalence of amphenicol-resistant Escherichia coli (E. coli) isolated from pig in mainland China from 2000 to 2018, a random-effects model was selected, then followed by meta-analysis. RESULTS: A total of 103 articles were included in the study. The results of the meta-analysis revealed that the pooled summarized prevalence of resistance to chloramphenicol (CAP) was 72.31% (95% confidence interval (95% CI) = 67.12%–77.23%) and to florfenicol (FF) was 58.64% (95% CI = 52.48%–64.67%). During the past 18 years, the resistance rate to CAP remained high initially but then declined rapidly after 2012, whereas the resistance rate to FF plateaued (54.13%–59.60%) from 2000–2018. In different parts of China, the rate of resistance to amphenicols among E. coli isolates was fairly consistent, with the exception of the north and northwest regions. CONCLUSIONS: In 2002, the veterinary use of CAP was prohibited and its resistance levels in E. coli isolated from pigs was initially maintained at a high level but then showed an obvious downward trend in recent years. Resistance to commonly used FF remained at a high but stable level.