Bacterial Community Profiling and Analysis of Antibiotic Genes (ARGs) in Selected Samples from Balili River

Tallad, Jay-Ann A.

Antimicrobial resistance (AMR) is a global concern for human and animal health, it is also gaining attention in non-clinical environments. However, antibiotic resistance genes (ARGs) contamination in Philippine rivers is rarely studied. The Balili river receives wastewater containing various contaminants from Baguio City and Benguet, making it a potential reservoir for ARGs and antibiotic residues. This study aims to analyze the presence of antibiotics in water samples using mass spectrometry. Sulfamethazine was detected from Benguet State University (BSU) site at 0.0392 ug.ml and a putative semi-synthetic macrolide derived from erythromycin was detected in BSU, North Sanitary Camp (NSC0 and Strawberry Farm (STW) water samples. Antibiotic resistant bacteria (ARB) with resistance to erythromycin (macrolide class) sulfamethazine (sulfonamide) and tetracycline hydrochloride (tetracycline) were cultured from water, sediment and Lactuca sativa samples. Genes encoding resistance to macrolide (ermA , ermB, mphF), sulfonamide (sul1, sul2 , sul3), tetracycline (tetA, tetO, tetW), and were detected using polymerase chain reaction (PCR). A strong negative correlation (p < .05) was found between sulfamethazine and sul resistance genes. Several genera of ARB from 16S rRNA analysis were associated with opportunistic pathogens e.g., Klebsiella, Pseudomonas, Acinetobacter, Bacillus, and Microbacterium among others. Bacterial community composition determined by next generation sequencing revealed that phylum Proteobacteria was dominant. The findings indicate that the Balili River is contaminated with antibiotics, and even though these occur in low concentrations in the environment, these may select for ARB accelerating the spread of AMR. This study shows that surveillance of antibiotic pollution is important to protect the ecosystem, humans and animal health from AMR.