This study reveals the high prevalence of multidrug-resistant Escherichia coli from healthy broilers, carrying extensive virulence genes and integrons, indicating poultry as an important host for resistant bacteria, posing a potential threat to human health.
Literature Overview
The article 'Phenotypic and Molecular Study of Multidrug-Resistant Escherichia coli Isolates Expressing Diverse Resistance and Virulence Genes from Broilers in Tunisia', published in the journal Antibiotics, reviews the molecular characteristics of antimicrobial resistance, virulence genes, and integrons in 111 Escherichia coli isolates from broiler ceca in Tunisia. The study found all strains exhibited multidrug resistance, with 72.1% producing extended-spectrum β-lactamases (ESBL) and blaCTX-M-G1 as the most common ESBL gene. Additionally, some strains carried carbapenem resistance genes blaOXA-48 and blaIMP, as well as colistin resistance gene mcr-1. The study emphasizes the potential public health risks of these resistant strains and supports integrated surveillance through a One Health approach.
Background Knowledge
Escherichia coli (E. coli) is a common intestinal commensal in humans and animals, but certain pathogenic strains cause intestinal or extraintestinal infections. Recently, ESBL-producing and carbapenem-resistant E. coli have emerged as global public health concerns, particularly due to antibiotic overuse in agriculture and livestock breeding, which accelerates horizontal gene transfer. Integrons (e.g., class 1 and class 2) act as mobile genetic elements facilitating integration and dissemination of resistance genes. This study focuses on multidrug-resistant E. coli isolates from Tunisian broilers, investigating their distribution of resistance genes, virulence factors, and integrons while analyzing phylogenetic groups. It provides molecular epidemiological data on resistant E. coli in poultry and highlights their potential transmission risks to human health, offering critical references for global antimicrobial resistance monitoring.
Research Methods and Experiments
111 E. coli isolates were collected from cecal samples of healthy broilers from three major poultry meat suppliers in Tunisia. Bacterial cultures were performed on MacConkey agar supplemented with cefotaxime. PCR amplification was employed to detect β-lactamase genes (blaCTX-M-G1, blaTEM, blaSHV, blaCMY, blaOXA-48, blaIMP), virulence genes (fimH, traT, iutA, bfpA, fyuA, stx-1, stx-2), and integrons (intI1 and intI2). Gene cassette structures within integrons were analyzed via sequencing, and statistical analyses were conducted using SPSS to evaluate distribution differences among resistance genes, virulence profiles, and phylogenetic groups.
Key Conclusions and Perspectives
Research Significance and Prospects
This study provides critical epidemiological data on multidrug-resistant E. coli in Tunisian broilers, underscoring the risk of zoonotic transmission through the food chain, which could compromise clinical treatments. Future research should integrate MLST and whole-genome sequencing to elucidate horizontal transfer mechanisms of resistance genes and assess the impact of antibiotic usage patterns on resistance evolution.
Conclusion
This study represents the first systematic investigation of multidrug-resistant ESBL-producing E. coli in Tunisian broilers, revealing high prevalence and co-carriage of virulence genes and integrons. The findings highlight the potential for zoonotic transmission through the food chain, leading to treatment failures and public health crises. Strengthening One Health surveillance, restricting antibiotic misuse, and preventing further dissemination of resistance genes are strongly recommended. Cyagen Biosciences offers related animal models, gene editing cell lines, and molecular detection services to support antibiotic resistance research, including gene knockout, overexpression, point mutation cell line construction, and assays such as qPCR, Western blot, and flow cytometry, advancing studies on resistance mechanisms, host-pathogen interactions, and novel therapeutic strategies.
