Antibiotic Bioresistance Profile of Residual Bacteria Attached to Plastics in Lake Nokoué and Its Implications for Waterborne Diseases: The Case of the Abomey-Calavi Dock

The increasing accumulation of plastics in aquatic environments represents a major environmental and public health concern, particularly in densely populated urban areas with intense human activities. These plastics serve as substrates for antibiotic-resistant pathogenic bacteria, thereby exacerbating the dissemination of resistance genes—a global public health challenge. To assess this issue, samples were collected from Lake Nokoué. The main objective of this study was to characterize the bacterial profile and antibiotic bioresistance of bacteria colonizing plastic residues in Lake Nokoué and to evaluate their potential impacts on public health, particularly concerning waterborne diseases, in order to prevent health risks associated with waste mismanagement. A total of forty-five samples were analyzed at the Laboratory of Research and Services in Human Biology (LRPBH) over a three-month period, using standard bacteriological identification and antimicrobial susceptibility testing methods. Results revealed a high prevalence of pathogenic bacteria, with Staphylococcus aureus (48.3%) being the most dominant species, followed by thermotolerant coliforms such as Escherichia coli (11.5%), Citrobacter freundii (12.7%), and Enterobacter cloacae (2.3%). Pathogenic Salmonella strains were also isolated, including Salmonella spp. (12.7%), Salmonella arizonae (9.2%), and Salmonella typhi (3.3%). Antibiotic susceptibility testing revealed particularly high resistance levels in Staphylococcus aureus and enterobacteria against tobramycin (TOB), gentamicin (CN), ertapenem (ETP), amoxicillin (AML), oxacillin (OX), erythromycin (E), and colistin (CT), with marked multidrug resistance to carbapenems. These findings clearly demonstrate that plastics discarded into aquatic systems act as potential reservoirs for resistant pathogenic microorganisms, thereby increasing the risk of waterborne diseases in the region. The results underscore the urgent need to strengthen sustainable plastic waste management and to implement enhanced microbiological surveillance to mitigate public health risks.