Bacterias resistentes a antibióticos en aguas superficiales de la región pampeana, Argentina

Introduction:Antibiotics are widely used in human and veterinary medicine for the therapeutic treatment of infectious diseases. They can reach the aquatic environment after being used in animal husbandry as growth promoters and for therapeutic purposes. In this work, the presence of antibiotic-resistant bacteria in the natural canal system that connects a feedlot in the Pampa Ondulada with the Arroyo Burgos, in the Province of Buenos Aires, was evaluated. Method: The prevalence of Gram-negative bacilli resistant to veterinary and human antibiotics was determined. The antibiotic sensitivity of selected Gram-negative bacteria was evaluated by the disk diffusion method. Bacterial isolates resistant to ceftazidime or cefotaxime were designated as suspected ESBL producers. Potential ESBL-producing isolates were confirmed by the disk diffusion method with clavulanic acid. Results: Among the isolated strains we find: Escherichia coli, Enterobacter cloacae, Pseudomonas fluorescens, Cedecea davisae and Pseudomonas oryzihabitans. In the resistance profile we can observe high resistance to third-generation cephalosporins for clinical use such as ceftazidime and cefotaxime. According to phenotypic assays, 60% of ceftazidime-resistant strains are ESBL producers. Conclusions: Diffuse contamination with bacteria resistant to beta-lactam antibiotics for both veterinary and clinical use could be determined. These results represent a problem for public health.