Abstract
Background and objectives: Urinary tract infections are one of the most common bacterial and nosocomial infections. They are one of the most important causes of septicemia, resulting in high mortality rate. Hence, detection of susceptibility patterns of isolated strains have a crucial role in treatment of urinary tract infections (UTI).
Materials and Methods: This is a descriptive – analytical cross sectional study, that was performed on Escherichia coli isolated from 102 inpatients and 103 outpatients with UTI, who were admitted to Imam Khomeini Hospital, Tabriz. In this study, resistance pattern of Escherichia coli isolated from inpatients and outpatients were separately determined against common antibiotics using disk diffusion (Kirby- Bauer) and agar dilution methods. Then the results obtained from inpatients and outpatients groups were compared. In the second part of the research, prevalence of nosocomial urinary tract infection and related risk factors consisting using of catheter, underlying diseases, previous antibiotic consumption were evaluated according to prepared questionnaire.
Results: In this study, minimum inhibitory concentration (MIC) of some antibiotics (nitrofurantuin, cephalothin, gentamicin and nalidixic acid) against Escherichia coli isolated from inpatients and outpatients were determined separately. MIC and antibiotic resistance among strains isolated from inpatients were higher than those isolated from outpatients, but the correlation was not significant, expect to nitrofurantuin and nalidixic acid (p<0.05). Escherichia coli isolated from outpatients and inpatients with UTI, showed the most resistance to ampicillin (85.4%, 92.2%) and the least resistance to nitrofurantuin (1.9%, 3.9%), respectively. Among 102 inpatients under the study, 24 cases (%23.5) had nosocomial urinary tract infections, with 20 (35.7%) of them having record of using catheter. This result, showed that, the correlation between acquisition of nosocomial infection and catheter use was significant (p<0.05).
Conclusion: Considering the high prevalence of nosocomial infection and bacterial resistance, it is necessary to prevent the predisposing factors of nosocomial infections, such as inappropriate use of medical equipment, irrational prescription of antibiotics, and attention to hygienic principles. According to our results, effective drugs for treating of UTI are still nitrofurantuin and gentamicin.