Frequency and Antimicrobial Susceptibility Pattern of Escherichia Coli Isolated from Urine Specimens at a Tertiary Care Setting

Abstract

Objective: To find out frequency and antimicrobial susceptibility pattern of Escherichia coli isolated from urine specimens at a tertiary care setting. Methodology: This descriptive study was done at department of microbiology, Armed Forces Institute of Pathology, Rawalpindi from January to December 2012. Semi-quantitative culture was done using strip method and only those urine specimens, which revealed the growth of Escherichia coli were included in the study. Antimicrobial susceptibility pattern of these isolates was noted against routinely used antibiotics (nitrofurantoin, meropenem, imipenem, amikacin, piperacillin-tazobactum, cefoperazone-sulbactum, piperacillin-sulbactum, gentamicin, ceftriaxone, ampicillin, ciprofloxacin, trimethoprim-sulphamethoxazole, amoxycillin-clavualanic acid and pipemadic acid). Results: A total of 10831 urine specimens were submitted for culture and drug susceptibility testing during the period of study. Out of these, 1904 specimens showed growth of different bacteria. Out of 1904 positive cultures, 990 (52%) were identified as Escherichia coli. Imepenem (96.3 %), Meropenem (92.9 %), Amikacin (83.7 %) and Nitrofurantoin (82.3 %) were the most sensitive, whereas trimethoprim-sulphamethoxazole (24% sensitivity), ciprofloxacin (29% sensitivity) and amoxycillin-clavualanic acid (26% sensitivity) were the least sensitive antibiotics against E.coli. Conclusion: E.coli was the most common isolated organism from urine cultures. In vitro susceptibility of imepenem, meropenem and nitrofurantoin was found to be higher compared to other antimicrobials. On the contrary in vitro susceptibility of trimethoprim-sulphamethoxazole, ciprofloxacin and amoxicillin-clavulanic acid was found to be extremely low.