Resistance to Antibiotics in Clinical Isolates of Extended-Spectrum Beta-Lactamase (ESBL)-Producing Escherichia coli Obtained from Urine Cultures in Patients with Urinary Tract Infection

The objective of this study was to identify strains of Escherichia coli producing extended spectrum beta-lactamases (ESBL) in urine cultures and to evaluate the patterns of resistance to certain antibiotics used in clinical practice as treatment of choice in the Valley of Toluca, Mexico. One hundred and fifty-five urine samples were obtained from people in the Toluca Valley, Mexico, under the necessary hygiene con¬ditions, 100 ml used to identify the pathogen and its resistance patterns were collected from each sample through an automated WalkAway method. In order to determine ESBL, a double disk technique was used. Nineteen ESLE-producing strains of E. coli were obtained, of which 100% showed resistance to ampicillin and cephalosporins, to tetracycline 93.75% resistance, levofloxacin 87.5% and ciprofloxacin 81.25%, and sensitivity of 100% to amikacin and carbapenemics. In conclusion, antibiotic resistance represents a major health problem. As the present study shows, ampicillin is a drug of choice for urinary tract infectioncaused by E. coli, but in the Toluca Valley the resistance to this antibiotic is 100% in ESBL-producing strains, which also show high resistance patterns to cephalosporins, quinolones, tetracycline and trimethoprim with sulfamethoxazole.