Multidrug resistance and extended-spectrum β-lactamases genes among Escherichia coli from patients with urinary tract infections in Northwestern Libya

Abstract

Introduction: Multidrug resistance (MDR) and emergence of extended-spectrum β-lactamases (ESBLs) that mediate resistance to β-lactam drugs among Escherichia coli and other uropathogens have been reported worldwide. However, there is little information on the detection of ESBLs genes in E. coli from patients with urinary tract infections (UTIs) in the Arab countries using polymerase chain reaction (PCR), and in Libya such information is lacking.

Methods: All patients attending Zawiya Teaching Hospital in Zawiya city between November 2012 and June 2013 suspected of having UTIs and from whom midstream urine samples were taken as part of the clinical workup were included in this prospective study. Samples were examined for uropathogens by standard bacteriological procedures. VITEK-2 automated microbiology system was used to identify the isolated uropathogens and determine the susceptibility of E. coli and Klebsiella spp. isolates to antimicrobials. In addition, phenotypically ESBLs-positive E. coli isolates were tested for ESBLs genes by PCR.

Results: The present study enrolled 1,790 patients with UTIs. Uropathogens were found in 371 (20.7%) urine specimens examined. Mixed pathogens were detected in two specimens with 373 total pathogens isolated. E. coli and Klebsiella spp. were the predominant uropathogens at 55.8% (208/373) and 18.5% (69/373), respectively. Other pathogens were detected in 25.7% (96/373) of urine samples. Of the E. coli and Klebsiella spp. tested, 69.2 and 100% were resistant to ampicillin, 6.7 and 33.3% to ceftriaxone, and 23.1 and 17.4% to ciprofloxacin, respectively. MDR (resistance to ≥3 antimicrobial groups) was found in 69 (33.2%) of E. coli and in 29 (42%) of Klebsiella spp. isolates. ESBLs were detected phenotypically in 14 (6.7%) of E. coli and in 15 (21.7%) of Klebsiella spp. isolates. Thirteen out of the 14 phenotypically ESBL-positive E. coli were positive for ESBL genes by PCR. bla TEM gene was detected in seven isolates, bla OXA gene in 10 isolates and bla CTX-M gene in six isolates. bla SHV gene was not detected in the present study.

Conclusion: The isolation of MDR ESBL-producing uropathogens undoubtedly will limit the choices clinicians have to treat their patients with UTIs. Therefore, there is an urgent need for surveillance studies on antimicrobial resistance and prevalence of ESBLs among uropathogens to guide the clinical treatment of UTIs in Libya in the future.

Keywords: Escherichia coli; Libya; extended-spectrum β-lactamases; multidrug resistance; urinary tract infections.

Fig. 1

PCR products of bla _CTX-M (lines 1–8 and 9–14); L 100 bp ladder and 50 bp ladder. pos=positive control and neg=negative control.