Evaluation of the microbiological water quality in rivers across Lebanon by assessing densities of fecal indicators and antibiotic resistance profiles of Escherichia coli

Abstract

Emerging microbial agents and increasing antibiotic resistance in aquatic systems pose a global concern worldwide. However, in. Lebanon, limited data on fecal pollution, bacterial indicators, and associated antibiotic resistance in rivers are available. The objective of this study was to evaluate the microbiological quality of rivers across Lebanon by assessing the densities of fecal indicators and antibiotic resistance profiles of Escherichia coli. For this purpose, 135 freshwater samples were collected from 14 major rivers in Lebanon. Results showed that 129 samples yielded E. coli colonies and 130 yielded fecal coliforms. Overall, the highest counts of fecal indicators were detected in Beirut river and Abou Ali river in the North. Three E. coli were isolated from each sample and subjected to disk diffusion assay. Therefore, ~ 388 E. coli were isolated from the 135 freshwater samples. Antimicrobial susceptibility analysis resistance showed that the E. coli isolates were resistant to penicillin (100percent), ampicillin (40percent), cefalexin (46percent), amoxicillin-clavulanic acid (40percent), cefepime (4percent), cefotaxime (14percent), cefixime (17percent), Doripenem (0.3percent), imipenem (1percent), meropenem (0.3percent), gentamicin (5percent), kanamycin (9percent), streptomycin (35percent), tetracycline (34percent), ciprofloxacin (11percent), norfloxacin (8percent), trimethoprim-sulfamethoxazole (31percent), and chloramphenicol (13percent). In addition, carbapenem resistance was detected in the E. coli isolated from the North of Lebanon (0.3percent). 45.3percent of the isolates (176 out of 388) were multi-drug resistant, and the highest numbers were in Beirut (61.1percent) and Beqaa (48.4percent). The high numbers obtained suggest that a proper treatment of wastewater before discharge into rivers and the control of use of antibiotics are a must to prevent the dissemination of antibiotic-resistant bacteria.