Evaluating Antibiotic Resistance in Urban Rivers and Coral Reefs of Belize: Evidence for Hotspots and a Potential Screening Tool.

Antibiotic resistance is a significant threat to global public health and can disproportionately affect low- and middle- income countries (LMICs). There is a lack of studies focusing on antibiotic resistance in coral reef regions and environmental reservoirs in Central America. This study followed modified World Health Organization (WHO)'s Global Tricycle Surveillance protocols for the environmental sector to address these gaps. Water samples were collected from key areas in the lower Belize River, including above and below the Belize City, an open fish market, and sewage lagoon outfall, and coral reefs. Water samples underwent qPCR analysis for a suite of antibiotic resistance gene classes (sul1, sul2, ermF, tetA, and blaSHV), intI1, and 16S rRNA. Additionally, a subset of samples were tested for extended-spectrum β-lactamase (ESBL) E. coli and underwent shotgun sequencing. Results show that antibiotic resistance genes (ARGs) were highest and most diverse near Belize City, particularly near the treatment lagoons and open fish market. The coral reef regions had lower levels of antibiotic resistance though not void of their presence. This study is an application of a modified Global Tricycle Surveillance protocol integrated with qPCR- and metagenomics-based characterization of environmental antibiotic resistance in understudied areas. Notably, data from this study indicated that ESBL-E. coli could potentially be used as a screening tool for environmental antibiotic resistance, as it was only present at sites that had the highest levels of ARGs.