Antibiotic Resistance Profiling of Pathogenic Enterobacteriaceae from Cluj-Napoca, Romania

Introduction: Members of the family Enterobacteriaceae are commonly identified in the clinical laboratory, being responsible for a substantial range of infections. This study aimed to investigate phenotypic and genotypic resistance traits in pathogenic Enterobacteriaceae isolated from outpatients in Cluj-Napoca, Romania. Methods: Pathogenic Enterobacteriaceae were isolated from urinary tract infections, wound infections and persistent diarrhea in a private laboratory from Cluj-Napoca, Romania. Bacterial strains were biochemically identified and subjected to antimicrobial susceptibility testing by disk diffusion. The carriage of antibiotic resistance genes and of class 1 integron were assessed by PCR. Results: E. coli and Enterobacter spp. were the most prevalent pathogens. High levels of resistance were observed against folate pathway inhibitors (74%), fluoroquinolones (49%) and penicillins (44%). The incidence of carbapenem resistance was 3%. The strains displaying phenotypic resistance were able to produce β-lactamase enzymes encoded by bla_TEM, bla_TEM-1, bla_SHV-1 and bla_CTX-M, aminoglycoside modifying enzymes due to the carriage of aac(3)-IIIa,aac(6')-II and aac(6’)-Ie-aph(2”), to possess fluoroquinolones resistance due to qnrS DNA gyrase protection proteins and resistance to folate pathway inhibitors due to dihydropteroate synthases encoded by sul1, sul2 and sul3 genes. The high frequency of intI1 integrase was associated to sulphonamide resistance (r = 0.48; p < 0.001) and also to fluoroquinolone resistance (r = 0.27; p = 0.011), but no significant associations in the co-occurrence of specific antibiotic resistance genes and intI1 were found in pathogenic Enterobacteriaceae. Conclusions: An important proportion of pathogenic Enterobacteriaceae were multidrug resistant, due to a wide diversity of mechanisms encoding genetic resistance.