High prevalence of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in a tertiary care hospital in Tehran, Iran.
BACKGROUND
Extended-spectrum beta (beta)-lactamase (ESBL)-producing enterobacteria are major emerging pathogens in nosocomial infections.


METHODS
The combination disk synergy test was used to evaluate 202 consecutive non-repeated Klebsiella pneumoniae (K. pneumonia) strains for ESBL production. The strains were isolated from various clinical specimens of hospitalized patients over the period from July 2005 to March 2007. Their antibiotic susceptibility pattern was also determined by the disk diffusion method. Demographic and medical data of the patients were recorded using a questionnaire.


RESULTS
One hundred and fifty-seven (77.7%) of the isolates were confirmed as ESBL-producers. By univariate analysis, young age, stay in intensive care unit (ICU)/medical wards, recent stay in ICU, and number of days of ICU stay were found to be risk factors for acquisition of resistant bacteria (chi(2) and Mann-Whitney U tests, P < 0.05). However, binary logistic multivariate regression analysis confirmed that stay in ICU [Odds ratio (OR) 6.09, 95% confidence interval (CI) 2.36-15.72; P < 0.001] or medical wards [OR 3.72, 95% CI 1.42-9.75; P = 0.007] were significantly associated with ESBL production. Imipenem, ofloxacin, cefoxitin and norfloxacin (against urinary isolates) were found to be highly active against ESBL-producing isolates in vitro (100%, 75.2%, 69.4% and 66.7% susceptibility, respectively). In addition to most beta-lactams, they showed co-resistance with other antibiotics such as ciprofloxacin, aminoglycosides, trimethoprim/sulfamethoxazole and tetracycline.


CONCLUSIONS
Our results showed a high prevalence of ESBL-producing K. pneumoniae in our hospital setting. As the available treatment options are limited, antibiotic control policies together with the implementation of infection control measures remain of high importance.
Mehrgan
Hadi
H
Department of Pharmaceutics, School of Pharmacy and Pharmaceutical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. hmehrgan75@yahoo.com
Rahbar
Mohammad
M
Arab-Halvaii
Zohreh
Z
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D003422:Critical Care; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology* / Q000628:therapy; D024901:Drug Resistance, Multiple, Bacterial; D005260:Female; D006761:Hospitals; D006801:Humans; D007223:Infant; D007492:Iran / Q000453:epidemiology; D007710:Klebsiella Infections / Q000453:epidemiology* / Q000382:microbiology* / Q000628:therapy; D007711:Klebsiella pneumoniae / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D015995:Prevalence; D012307:Risk Factors; D001618:beta-Lactamases / Q000096:biosynthesis*
D000900:Anti-Bacterial Agents; D001618:beta-Lactamases