Distribution of classes 1 and 2 integrons among multi drug resistant E. coli isolated from hospitalized patients with urinary tract infection in Cairo, Egypt

Many recent studies have demonstrated an increase of multi drug resistant (MDR) uropathogenic Escherechia coli (E. coli) which is considered as the most common cause of urinary tract infections (UTIs). Present investigation was undertaken to know antibiotic resistance pattern of E. coli and some other pathogens causing UTIs obtained from urine samples. Special emphasis was given on plasmid mediated transferable antibiotic resistance in E. coli as well as the mobilized integrons (classes 1 and 2) that contribute to the spread of MDR. A total of 320 urine specimens were collected from patients with UTI followed by isolation and identification of their bacterial pathogens. Antimicrobial sensitivity and resistance pattern was performed by the disc diffusion method employing recommended antibiotic discs. The sensitivity was monitored by zone of inhibition according to the National Committee for Clinical Laboratory Standards (NCCLS) guidelines. Plasmid DNA from isolated E. coli strains was tested for class 1 and 2 integrons by PCR compared to other isolated strains, E. coli was prevailed and accounted for 58.75% of all strains, followed by Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus spp., Enterobacter cloacae, Staphylococcus aureus and Proteus mirabilis. Strains of E. coli were 100% resistant to ampicillin, amoxicillin, cephalexin and chloramphenicol, followed by tetracycline (79.3%), sulphamethoxazole-trimethoprim (SMX/TMP) (69.7%), ampicillin/sulbactam (67.1%), erythromycin (49.5%), amoxicillin/clavulanate (45.7%), nalidixic acid (37.8%), ciprofloxacin (35.6%) norfloxacin (34%), gemifloxacin (27.1%), gentamicin (27.1%) and imipenem (5.9%). All strains contained multiple number of plasmids ranged from 3 to 6 and appeared in 84% of E. coli strains. Int1 gene yielded a DNA fragment of 1.9 kb upon amplification by PCR and represented in 56% of E. coli isolates. The strong association observed between plasmid profiles and drug resistance patterns suggest that plasmids have epidemiological significance. A relatively high occurrence of class 1 integrons in E. coli strains (54%) suggests a correlation between the MDR behavior and the presence of transferable elements of these strains. Imipenem, gemifloxacin and gentamicin could be used for initial therapy for MDR E. coli mediated UTIs. Such studies are essential to determine the current guidelines for empirical therapy regimens which vary by location and helpful in the establishment of effective infection control measures.