Effect of pharmaceutical manufacturing waste on the environmental resistome of a pharmaceutical manufacturing hub in India

Antimicrobial resistance (AMR) is one of the top global health threats estimated to cause over 10 million deaths by 2050. To tackle this crisis, a One Health approach acknowledging the interconnectedness across human, animal and environmental health is essential. Over the last few decades, evidence has accumulated that the environmental dimension of AMR has been exacerbated by increased pollutants (e.g. pharmaceuticals, heavy metals, etc) being released in the environment from different sources, driving selection of antimicrobial resistance genes (ARGs) in microbial communities and pathogens. Pharmaceutical manufacturing is a major source of release into the environment of high concentrations of active pharmaceutical ingredients (APIs) - including antimicrobials, representing an increased risk of selection of AMR and exposure to human health. This study investigated the effect of environmental pollution from pharmaceutical manufacturing waste on the selection of ARGs in Baddi, one of the largest pharmaceutical manufacturing hubs in India, located in the state of Himachal Pradesh. Comparative analyses were performed with samples collected in Kangra, an unindustrialised municipality in the same area. Results have shown that APIs were detected only in Baddi, particularly in the waste stream from manufacturing plants, across different seasons. These samples also showed higher levels of ARG and mobile genetic element (MGE) diversity and relative abundance compared to the surrounding areas, including clinically important genes associated with extended spectrum beta-lactamases and carbapenemases. At both locations, a background pollution from faecal sources was observed, contributing to the resistome (i.e., the collection of ARGs present in the sample) observed in these environments. However, the presence of manufacturing pollution has likely impacted the selection of specific ARGs in the industrialised hub. These results highlighted the potential increased risk of exposure to higher levels and more diverse ARGs in pharmaceutical manufacturing waste-impacted areas. This further demonstrates the need to implement more robust standards for pharmaceutical manufacturing waste as supported by the AMR Industry Alliance and the World Health Organisation to protect the environment and human health.