Increasing prevalence of extended spectrum lactamases producers among common uropathogens in a Greek tertiary-care hospital: a 3year comparative study

Abstract number: R2108

Mamali V., Altouvas G., Giannouli A., Zarkotou O., Sotiropoulou E., Kopsari K., Digalaki K.

Objectives: Urinary tract infections (UTI) remain the most frequent infections diagnosed in outpatients as well as in hospitalised patients. We comparatively evaluated the prevalence of extended spectrum b-bactamases (ESBL) producing (ESBL+) Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis among urinary isolates during the last three years. Resistance rates to fluoroquinolones (FQs) and trimethoprim/sulfamethoxazole (TMP-SXT), antimicrobial agents commonly prescribed as per os treatment in patients with UTI, were also studied.

Methods: A total of 3842 strains isolated from urine cultures were collected from 2685 hospitalised patients and 1157 outpatients during a 3-year period (2006–2008). Species identification and antimicrobial susceptibility testing was performed by VITEK 2 Compact automated system (bioMérieux). ESBL-production was screened by double-disc synergy test (DDST) and confirmed by combined disk test (ceftazidime and cefotaxime with and without clavulanate), according to CLSI guidelines.

Results: Among urinary isolates, the prevalence of ESBL-producers was 1.3% in 2006 (17/1300), rising to 2.2% in 2007 (29/1326). A remarkable increase (7.1%) in ESBL producers was noted in 2008: 86/1216 isolates carried ESBL. Regarding E. coli, the number of ESBL+ isolates rose from 12 in 2006 to 22 in 2007. A more than 5-fold increase was observed in 2008 (69 isolates). The increase of prevalence of ESBL producers was significant but less notable for K. pneumoniae: 5, 7 and 14 were recovered in 2006, 2007 and 2008 respectively. P. mirabilis ESBL+ was first detected in 2008 (3 isolates). The comparative study of resistance rates revealed that non-ESBL producers expressed low resistant rates to FQs and TMP-SXT as compared to ESBL producers. No significant differences were observed in resistance rates from 2006 to 2008. Resistance rates are presented in detail in the table.

Conclusion: Increasing spread of ESBL-producers among urinary isolates along with high resistance rate to fluoroquinolones and trimethoprim/sulfamethoxazole, either in hospital or community settings, generate a therapeutic challenge because of limited oral therapeutic options. Monitoring of ESBL production and antimicrobial susceptibility testing are necessary to avoid treatment failure in patients with UTI.

 % resistance

Session Details

Date: 16/05/2009
Time: 00:00-00:00
Session name: 19th European Congress of Clinical Microbiology and Infectious Diseases
Location: Helsinki, Finland, 16 - 19 May 2009
Presentation type:
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