Study of Drug-Resistant E. coli in Chicken Meat

Jim Crocker
17th May, 2025

Study of Drug-Resistant E. coli in Chicken Meat

Heatmap analysis confirms the widespread presence of multidrug-resistant phenotypes and associated genes, specifically blaTEM, sul1, and sul2, in Escherichia coli isolates from broiler chicken meat obtained from Live Bird Markets (a) and Supermarkets (b).

Image adapted from: Khanom et al. / CC BY (Source)

Key Findings

  • In Chattogram, Bangladesh, over half of poultry meat samples were contaminated with E. coli bacteria
  • Most E. coli were resistant to common antibiotics like ampicillin and tetracycline
  • Many E. coli strains were resistant to multiple drugs, increasing health risks for consumers
Ensuring the safety of poultry products is crucial for public health, especially in the face of rising antimicrobial resistance (AMR) in foodborne pathogens. AMR occurs when bacteria evolve to withstand the effects of antibiotics, making infections harder to treat. This study, conducted by the Chattogram Veterinary and Animal Sciences University[1], investigates the prevalence and AMR patterns of Escherichia coli (E. coli) in broiler chicken meat from live bird markets and supermarkets in the Chattogram Metropolitan Area (CMA), Bangladesh. The research addressed a significant problem: the high contamination rate of E. coli in poultry products and the associated AMR, which poses a threat to both animal and human health. Previous studies have highlighted the interconnectedness of antimicrobial use in veterinary and human medicine. For instance, in France, the same antimicrobials are used in both sectors, though the quantities differ markedly[2]. Additionally, in Bangladesh, the poultry sector is a major consumer of antimicrobials, often used irrationally and excessively, contributing to AMR[3]. This study builds on these findings by providing specific data on AMR in poultry products within a key region of Bangladesh. A total of 430 samples, including liver and muscle tissues from broiler chickens, were collected between October 2020 and February 2021 from nine live bird markets and five supermarkets in CMA. The samples underwent processing and culturing to isolate E. coli, which was then identified using both phenotypic methods and molecular techniques such as Polymerase Chain Reaction (PCR). PCR targeted specific genes, uidA and uspA, to accurately identify E. coli strains. The antimicrobial susceptibility of these isolates was tested using the Kirby-Bauer disk diffusion method against seven antibiotics from six different classes. The study revealed that 56.28% of the samples were contaminated with E. coli, with a slightly higher prevalence in live bird markets (58.33%) compared to supermarkets (54.80%). Liver samples showed a higher contamination rate than muscle samples in both settings. Alarmingly, the AMR profiling indicated high resistance rates to commonly used antibiotics such as sulfamethoxazole-trimethoprim (88.84%), tetracycline (86.78%), and ampicillin (82.23%). On the other hand, cephalexin and gentamicin remained more effective, with susceptibility rates of 63.64% and 57.02%, respectively. A significant portion of the isolates, 84.71%, were found to be multidrug-resistant (MDR), with some resistant to up to six different antibiotic classes. The multiple antibiotic resistance (MAR) index, which indicates the level of exposure to antibiotics, ranged from 0.14 to 1.00, underscoring substantial antimicrobial exposure in these environments. Molecular analysis further elucidated the mechanisms behind this resistance. All ampicillin-resistant isolates carried the blaTEM gene, which is known to confer resistance to beta-lactam antibiotics. Additionally, 75.35% of sulfamethoxazole-resistant isolates possessed the sul2 gene, linking genetic factors to phenotypic resistance[4]. Correlation analysis demonstrated a strong association between the presence of the blaTEM gene and resistance to ampicillin, and a moderate correlation between the sul2 gene and sulfamethoxazole resistance. These genetic insights are crucial as they indicate that resistance is not solely due to antibiotic use but is also genetically ingrained within the bacterial populations. This study's findings are particularly concerning given the previously documented knowledge, attitudes, and practices (KAP) of poultry farmers in Bangladesh regarding AMU and AMR. Many farmers lack sufficient understanding and rely on non-registered sources for antimicrobials, exacerbating the misuse and overuse of these drugs[3]. The high prevalence of MDR E. coli in poultry products reflects these practices and highlights the urgent need for intervention. Effective strategies must involve educating farmers, enforcing regulations on antimicrobial sales, and promoting responsible antibiotic use to mitigate the spread of AMR. Moreover, the study aligns with earlier research that demonstrates the link between antimicrobial selection pressure and the emergence of resistant and virulent bacterial strains[4]. The high MAR indices observed suggest that the poultry populations in CMA are under significant antimicrobial pressure, fostering environments where resistant strains can thrive and potentially transfer resistance genes to other bacteria, including those that cause human infections. Addressing AMR in poultry requires a multifaceted approach. Insights from this study can inform policies aimed at reducing antimicrobial use in animal husbandry, similar to the comparisons made in France between veterinary and human medicine[2]. By understanding the specific resistance patterns and the genetic mechanisms at play, targeted interventions can be developed to curb the spread of MDR bacteria. Additionally, improving the KAP among poultry farmers, as highlighted in the research, is essential for long-term sustainability in managing AMR. In conclusion, the high prevalence of MDR E. coli in broiler chicken meat from CMA's live bird markets and supermarkets poses a significant public health risk. This study not only quantifies the extent of AMR in poultry products but also links it to both antimicrobial usage practices and genetic factors. Addressing this issue requires coordinated efforts involving education, regulation, and ongoing surveillance to ensure the safety of poultry products and protect public health from the growing threat of antimicrobial resistance.

MedicineAgricultureHealth

References

Main Study

1) Epidemiology and molecular characterisation of multidrug-resistant Escherichia coli isolated from chicken meat

Published 14th May, 2025

https://doi.org/10.1371/journal.pone.0323909

Related Studies

2) A comparison of antimicrobial usage in human and veterinary medicine in France from 1999 to 2005.

https://doi.org/10.1093/jac/dkn213

3) Knowledge, Attitude, and Practices on Antimicrobial Use and Antimicrobial Resistance among Commercial Poultry Farmers in Bangladesh.

https://doi.org/10.3390/antibiotics10070784

4) Effects of selection pressure and genetic association on the relationship between antibiotic resistance and virulence in Escherichia coli.

https://doi.org/10.1128/AAC.01094-15


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