Impact of contrasting poultry exposures on human, poultry, and wastewater antibiotic resistomes in Bangladesh

Abstract

ABSTRACT Interactions between humans, animals, and the environment are considered critical foci for addressing antimicrobial resistance (AMR). However, One Health data on AMR in low- and middle-income countries are presently scarce. Using metagenomics, we investigated whether and how the fecal antibiotic resistomes of humans are influenced by exposure to intensive and non-intensively reared poultry within contrasting settings of urban wet markets (n = 13) and rural households (n = 7) in Bangladesh. We also considered poultry (n = 10) and wastewater (n = 10) resistomes in these settings. We found that occupational poultry exposures did not significantly alter the human fecal resistome. In contrast, macrolide-lincosamide-streptogramin and streptothricin antibiotic resistance genes (ARGs) were enriched in poultry from urban wet markets relative to rural household chickens. Wastewater had the highest ARG richness, though this was only partially explained by poultry cecal and human fecal sources. Wastewater also contained clinically significant carbapenem ARGs. This study therefore provides critical insight into the distribution of ARGs in Bangladesh. IMPORTANCE Through the use of DNA sequencing, our study shows that there is no significant difference in the antibiotic resistance genes found in stool samples taken from individuals with high exposure to poultry routinely fed antibiotics and those without such exposure. This finding is significant as it suggests limited transmission of antibiotic resistance genes between poultry and humans in these circumstances. However, our research also demonstrates that commercially reared poultry are more likely to possess resistance genes to antibiotics commonly administered on medium-sized farms. Additionally, our study highlights the under-explored potential of wastewater as a source of various antibiotic resistance genes, some of which are clinically relevant.

Keywords

• antibiotic resistance
• metagenomics
• one health
• environmental microbiology
• occupational exposure