Antibiotic resistance profile of Escherichia coli strains isolated in an infectious diseases clinic

Objective. To establish the resistance profile of Escherichia coli (EC) strains isolated in the Infectious Diseases Clinic from Craiova. Material and methods. Retrospective study (January 2017-December 2018); EC strains were identified using the automated Vitek 2 system, which subsequently established their susceptibility to antimicrobials (usual testing for 17 antibiotics, extended testing for another 9); for each strain the Multiple Antibiotic Resistance Index (MAR) was calculated (limits: 0-1); the information was entered into an Excel database. 128 strains were tested in 2017 and another 592 in 2018. The percentage of MDR strains was calculated based on internationally accepted definitions. Outcomes. 720 strains were identified, the vast majority isolated by urine culture (493 strains – 68.47%). Demographic data: 508 strains (71%) were isolated in adult subjects, 441 (61%) in female patients, 411 (57%) in patients living in urban areas. The overall value of MAR was 0.23. Over 80% of EC strains were susceptible to Ertapenem, Meropenem, Amikacin, Polymyxin E, Gentamicin, Tobramycin, Cefoxitin; susceptibility between 60 and 79% were observed for Cefepime, Ceftriaxone, Ciprofloxacin, Ceftazidime, Levofloxacin, Imipenem, Nitrofurantoin, Cefazolin, and between 40 and 59% for Trimethoprim-Sulfamethoxazole and Minocycline. Less than 39% of the strains were susceptible to Ampicillin (± Sulbactam), Piperacillin (± Tazobactam), Ticarcillin (± Clavulanate), Aztreonam, Pefloxacin. Resistance to the main classes of antibiotics is consistent with European and national data, except for a much higher percentage of carbapenemresistant strains. Over 50% of isolates are multidrug-resistant; 48.3% of the strains come from sources where there is significant contact with antimicrobials. Conclusions. Over 80% of the isolated strains are susceptible to Ertapenem, Meropenem, Amikacin, Polymyxin E, Gentamicin, Tobramycin, Cefoxitin; more than 4.5% of the strains demonstrate resistance to the carbapenem class; over 50% of isolates are multidrug-resistant; 48.3% of the strains come from sources where there is significant contact with antimicrobials