Caracterización microbiológica y evaluación de multirresistencias antibióticas en el Río Chibunga

Abstract

The objective of this research was to microbiologically characterize pathogenic species present in the Chibunga River in order to evaluate the presence of antibiotic multiresistances. To do this study, a triplicate sampling was performed in three places: Cemento Chimborazo sector, Ecological Park and the bridge at the entrance to Chambo, taking into account certain inclusion criteria. The samples were analyzed in the Microbiology laboratory of the Science Faculty of the Escuela Superior Politécnica de Chimborazo. For bacterial identification, serial dilutions of peptone water, selective and nutritive agars, gram stain to confirm that a pure culture was obtained, biochemical tests and, finally, to determine bacterial resistance, antibiograms were used in duplicate. Gram (-) bacilli belonging to the Enterobacteriaceae family; Escherichia coli, Yersinia enterocolitica, Klebsiella pneumoniae, Salmonella enterica, Salmonella paratyphi, Shigella flexnery, Proteus mirabilis and Edwardsiella tarda were determined. Also, Pseudomonas aeruginosa and Aeromonas hydrophila; and cocci gram (+): Staphylococcus aureus and Enterococcus faecalis. Most of them showed resistance to three or more antibiotics, the most common being: ampicillin, nalidixic acid and cephalozin. On the other hand, they showed sensitivity to amikacin, amoxicillin + clavulanic acid, aztreonam and cefotaxime. Staphylococcus aureus and Enterococcus faecalis are the bacteria with the highest multidrug resistance, since they are resistant to more than 5 groups of antibiotics. Finally, the MPN method was used to determine total coliforms, fecal coliforms and E. coli, bacteria indicative of water sanitation, where it was concluded that in the Chibunga river there is an excess of the permissible limits according to the TULSMA standard, presenting >1600 MPN.