Prevalence of quinolone-resistant urinary tract infections in Comanche County Memorial Hospital.

PURPOSE

Urinary tract infection (UTI) is not only a common outpatient but also the most frequently occurring nosocomial infection. The most common causative organisms of UTI remain Escherichia coli, nosocomial gram-negative bacilli, enteroccoci and candida. Many physicians use quinolones as the agent of choice for treatment of UTI. As calculated by the drug utilization data of 2007, the rate of quinolone use by physicians for UTI is 48%. This study was performed to determine the prevalence of quinolone-resistant UTI in our hospital and community.

METHODS

All patients admitted to Comanche County Memorial Hospital (CCMH) from Jan 2004 to July 2007 with documented positive urine cultures, as well as patients with hospital-acquired UTI's were included in this study. Pertinent data was collected by a retrospective review of medical records. Resistance of E. coli in urine to ciprofloxacin in total number of patients, divided in two age groups, was studied. X2 and P-value were calculated. Data was stratified for age and stratum specific resistance rate of different drugs (% and 95% CI) were calculated.

RESULTS

2000 cases of positive urine cultures were reviewed. The most common organism causing UTI was E. coli in 1225 (61%). Susceptibility reports showed that only 900 of 1225 E. coli (73.5%) were sensitive to quinolones and crude resistance rate to E. coli in older age group was as high as 26.5%. X2 = 200.922 and p-value < 0.001. Resistance was lowest in younger group (18-50), 3.2%, 95% CI of 1.6-4.7 and approached 41% in patients aged 51-90, (95% CI of 37-45). The sensitivity of E. coli to third generation cephalosporins was 100% and to 1st and 2nd generation was 90% and 98% respectively. Klebsiella was sensitive to both quinolones and third generation cephalosporins in 98% and 100% respectively. Other gram negative organisms (Proteus, Pseudomonas) were sensitive to quinolones in only 69% and 57% of cases respectively while being sensitive to cephalosporins (cefepime and ceftazidime in case of pseudomonas) in more than 99% cases.

CONCLUSION

Prevalence of quinolone-resistance to most common organisms causing urinary tract infections is significantly high in this community. (26.5% for E. coli). Therefore, in Comanche County Memorial Hospital and community, cephalosporins, preferably third generation, intravenous and oral preparations, rather than quinolones should be the first line of treatment, specially for elderly patients who are started on empirical therapy for UTI.