The occurrence of potential pathogenic antibiotic-resistant bacteria in the marine environment in Ha Long Bay, Vietnam

Abstract

This study aimed to investigate the occurrence of potential pathogenic bacteria from surface water samples collected at 30 stations along Ha Long Bay, Vietnam. Among 116 bacterial isolates identified, the composition analysis indicated 24 distinct bacterial genera, with Vibrio (29.3%), Pseudomonas (23.3%), Staphylococcus (8.6%), and Bacillus (6.0%) being the most dominant. The taxonomic analysis revealed 61/116 (52.6%) isolates as potential pathogens (risk group 2) belonging to 21 bacterial species. Potential pathogens were detected in 28/30 (93.3%) sampling stations, with the most common pathogens including Vibrio alginolyticus (n=25), Vibrioparahaemolyticus (n=5),Enterobacter cloacae (n=3), Pseudomonas mendocina (n=3), Aeromonas hydrophila (n=2), Enterobacter asburiae (n=2), Klebsiella oxytoca (n=2), Bacillus cereus (n=2),and Staphylococcus haemolyticus (n=2). The selected pathogens were highly resistant to Amoxicillin (100%), Piperacillin (100%), Amoxicillin + Clavulanate (85.7%), Ticarcillin (71.4%), Cefoxitin (54.4%), Kanamycin (50%), and Fosfomycin (50%), and less resistant to Trimethoprim + sulfamethoxazole, Fusidic Acid, Tetracycline, Erythromycin, Pristinamycin, Dalacin, and Rifampicin (<25%), and susceptible to the remaining antibiotics. Notably, 12/23 (52.2%) isolates were resistant to at least three antibiotics and were multidrug-resistant bacteria. Our findings underline that the occurrence of pathogenic antibiotic-resistant bacteria in the marine environment of Ha Long Bay presents a potential threat to human health. Further genomic surveillance studies are necessary to manage and control the emergence and spread of pathogenic-resistant bacteria in this area.