Antibiotic Resistance Pattern and Phylogenetic Groups of the Uropathogenic Escherichia coli Isolates Recovered from the Urinary Catheters of the Hospitalized Patients

Almost 80% of nosocomial urinary tract infections (UTIs) are due to catheterization. Catheter-associated UTI (CAUTI) is the primary source for colonization of antibiotic-resistant pathogens, and uropathogenic Escherichia coli (UPEC) is the most common causative bacteria. This study was conducted to determine the phylogenetic groups, and antibiotic resistance pattern as the two important features of pathogenicity of UPEC isolates collected from urinary catheters.
The UPEC isolates were obtained from the urinary catheters of the patients without UTI, from two referral hospitals during 2015 to 2016. Phylogenetic grouping was performed using a multiplex PCR. Antibiotic susceptibility and extended spectrum beta-lactamase (ESBL) production were tested by the disc diffusion method. Multidrug resistance was determined based on a recent guideline. The presence of some resistance genes was examined by a PCR assay.
Thirty-eight percent of the isolates were UPEC, all of them belonged either to B2 (62.5%) or D (37.5%) phylogenetic groups. The UPEC isolates showed a very high resistance to ciprofloxacin (80%) and the third-generation cephalosporins (72.5%). Seventy percent of the isolates were ESBL-producing, and 90% of them were multiple drug resistant (MDR). Meanwhile, the frequency of the resistance genes: ctxM, aacIV, sul1, shv, and qnrA in the isolates were 95%, 82.5%, 77.5%, 72.5%, and 45%, respectively.
High resistance to fluoroquinolones and third-generation cephalosporins, as well as high frequency of ESBL-producing and MDR UPEC isolates, are a great concern. This phenomenon is probably the consequence of the indiscriminate use and on the counter availability of antibiotics, which should be considered in empirical therapy of CAUTIs.