In the bustling dairy farms of Chattogram Metropolitan Area (CMA), Bangladesh, a silent crisis is brewing. A recent study published in ‘The Microbe’ (translated as ‘The Microbe’) has revealed alarming levels of antimicrobial resistance (AMR) in common bacteria found in bovine milk, posing significant public health and commercial risks. Led by Jahan Ara from the Department of Pathology and Parasitology at Chattogram Veterinary and Animal Sciences University, the research underscores the urgent need for improved hygiene and prudent antibiotic use in dairy farming.
The study, conducted from September 2020 to February 2021, analyzed 175 milk samples from ten dairy farms in CMA. The findings were stark: 40% of the samples tested positive for subclinical mastitis (SCM), a common udder infection that can significantly reduce milk production and quality. Among these, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) were the most prevalent pathogens, detected in 14.86% and 11.43% of the samples, respectively.
Antimicrobial susceptibility testing revealed a troubling pattern of resistance. “The high levels of resistance to commonly used antibiotics like tetracycline and ampicillin in S. aureus, and the universal resistance to ciprofloxacin in E. coli, are particularly concerning,” said Jahan Ara. Multidrug resistance (MDR) was rampant, with 88.5% of S. aureus and 80% of E. coli isolates showing resistance to multiple antibiotics.
The study also identified key AMR genes, including tetK and blaZ in S. aureus, and blaTEM and blaCTX-M in E. coli. Notably, 19.2% of S. aureus isolates were confirmed to be methicillin-resistant (MRSA), a strain known for its resistance to a wide range of beta-lactam antibiotics. Phylogenetic analysis further revealed that the MRSA isolates from Bangladesh formed a distinct genetic cluster, suggesting regional specificity in the resistance patterns.
The commercial implications of these findings are significant. Dairy farming is a vital sector in Bangladesh, contributing substantially to the national economy. However, the prevalence of AMR in bovine milk can lead to reduced milk yields, increased treatment costs, and potential trade restrictions due to public health concerns. “The higher incidence of these bacteria was significantly correlated with poor farm cleanliness,” noted Jahan Ara, emphasizing the need for improved hygienic procedures to mitigate bacterial contamination.
The study’s findings highlight the urgent need for a multi-faceted approach to tackle AMR in the dairy sector. This includes implementing stricter biosecurity measures, promoting prudent antibiotic use, and establishing robust AMR surveillance systems. As Jahan Ara aptly put it, “Urgent measures are needed to mitigate MDR risks and ensure the sustainability of the dairy industry.”
This research not only sheds light on the current state of AMR in Bangladesh’s dairy sector but also serves as a wake-up call for global agricultural and public health communities. The distinct genetic cluster of MRSA isolates underscores the importance of regional-specific strategies in combating AMR. As the world grapples with the broader issue of antimicrobial resistance, studies like this one provide valuable insights and a roadmap for future developments in the field.