Antibiotic and heavy metal resistance genes in hospital effluents and streams in Benin

Poor effluent management is known to release antibiotic resistance genes and heavy metal resistance genes into streams. The objective of this study was to investigate the occurrence of antibiotics and heavy metals in hospital effluents and streams in Benin. The extraction of genomic DNA from multidrug-resistant bacterial strains isolated from stream and hospital effluents samples was performed according to the recommendations of the Quick-DNA TM miniprep kit (Zymo Research Corp, United States). Real-time PCR was used to identify twelve antibiotic and six heavy metal resistance genes. The results showed that sulII (77.77%), sulI (67.67%), and blaTEM-1 (44.44%) were the resistance genes to antibiotics, the most detected in gram-negative bacilli isolated from hospital effluents. Two genes, tetA (33.33%) and ermB (20%), were found in gram-positive cocci. zntA (57.57%), czcA (24.24%), and copA (22.22%) are the genes encoding resistance to heavy metals, most found in gram-negative bacilli, but zntA (20%) and czcA (10%) were both found in Staphylococcus aureus isolates. Concerning streams, sulII (38.23%), sulI (26.47%), and blaTEM-1 (23.53%) were detected in gram-negative bacilli. czcA (38.23%), zntA (35.29%), and copA (11.76%) are the genes encoding heavy metal resistance found in gram-negative stream bacilli. These results highlight the need for measures to be taken to ensure the integrity of natural resources and thereby preserve human, animal and environmental health. Key words: Antibiotic and heavy metal resistance genes, hospital effluents and streams, Benin.