Tetracycline Resistance among Escherichia coli Isolates from Broilers in Iran: A Systematic Review and Meta-Analysis

Avian colibacillosis are infections caused by Avian Pathogenic Escherichia coli which causes high morbidity, high mortality, and significant economic losses. Antibiotics such as tetracycline are an important treatment choice for colibacillosis in Iran. However, the irrational use of antibiotics has caused high antibiotic resistance. The aim of this study was to estimate the tetracycline resistance rate among E. coli isolates from broilers in Iran.

PubMed, Scopus, Web of Science, Google Scholar, Islamic World Science Citation, Scientific Information Database, and MagIran databases were searched from 2013 and 2023. Risk of bias assessment was assessed with Appraisal tool for Cross-Sectional Studies. For meta-analysis, a random effects model with Freeman-Tukey double arcsine transformation was used. Subgroup analysis for the year of publication and sensitivity analysis to assess the influence of individual studies were conducted and a province-level map of point estimates was drawn.

Among 13 included studies, the pooled tetracycline resistance was 85% (95% CI: 76-92%) and I-squared was 94.29%. In subgroup analysis, resistance rate was higher for articles published in 2018-2023 (91%) compared to articles published in 2013-2017 (76%), but heterogeneity between groups was not statistically-significant (P=0.12). sensitivity analysis showed that the omission of individual studies caused no apparent change. The province-level map showed that most of the studies belonged to northern parts of Iran with Ardabil (99.65%) having the highest value.

Resistance against tetracycline in E. coli isolates from broilers in Iran is alarming. The sensible use of tetracycline is advised.