Antimicrobial resistance (AMR) significantly threatens animal food production globally. Endangering human and animal health, AMR bacteria can be transmitted across the animal-human interface, between species and bidirectionally between humans, animals and the environment, contaminating the entire food system. Thus, regions with a reliance on mixed farming systems – as found in many low- and middle-income countries (LMICs) – are particularly vulnerable to AMR.
Nigeria is one such country where dairy and tilapia industries are at risk from the emergence and spread of AMR. Bacterial-induced mastitis, a mammary gland inflammatory disease affecting bovine milk production, is widely undermined in Nigeria’s dairy industry. While several bacteria can cause mastitis, the methicillin-resistant bacteria Staphylococcus aureus ST88 (MRSA) is of particular concern. In other LMICs, MRSA has been identified in mastitis-affected cow’s milk and can be transferred to humans, as found in, for instance, Nigeria and India. More recently, in India, it has also been found in aquatic environments and tilapia (Oreochromis niloticus) specifically. Considering that MRSA is attributed to antibiotic overuse, the risk of developing MRSA in Nigeria is significant due to high prophylactic and metaphylactic antibiotic use: more than 60% of Nigerian dairy farmers use antibiotics without a prescription. The development of MRSA would have significant consequences to Nigeria’s dairy and burgeoning tilapia culture industry, as well as to human health.
Therefore, this study examines an antibiotic alternative for Nigerian dairy and tilapia farmers: bacteriocins. Bacteriocins are peptides produced by bacteria that exhibit broad-spectrum antibacterial activity (including to AMR bacteria), a reduced probability of resistance, with absent or limited toxicity to mammalian cells. While several herbal and essential-oil alternatives to antibiotics have been trialled, few have been approved for clinical use due to the complexity of their composition and the difficulty of accurately assessing efficacy and safety. Moreover, some bacteria are naturally resistant to herbal compounds, and others easily develop resistance over time. A combination of bacteriocins could be a realistic alternative to the use of antibiotics in LMICs because they are broad-spectrum, do not generate resistance, and can be produced as a bacteriocin-rich extract (BRE) easily and at a low cost.
This project aims to assess the potential of bacteriocins in preventing MRSA in Nigerian dairy and fish farms. Results will be presented from the project’s five components: (1) a study of factors influencing treatment decisions using systematic surveys and focus groups, (2) engineering and production of BRE, (3) field trials in tilapia farms, (4) field trials in dairy ruminant farms, and (5) cost-benefit analysis. In this presentation, we introduce preliminary results from the systematic surveys and focus groups, discuss their implications for field trials, and consider their effect on project outcomes and habitual use of BRE instead of antibiotics.