Extended-spectrum beta-lactamase-producing Enterobacteriaceae: recent evolution and clinical impact in a large tertiary-care Italian hospital

Abstract number: P675

Bartoloni A., Mantengoli E., Cavallo A., Cecconi D., Pecile P., Attala L., Nicoletti P., Paradisi F., Cauda R., Rossolini G.M.

Objectives: The extended-spectrum beta-lactamases (ESBLs)-producing Enterobacteriaceae represent a major public-health concern. Epidemiology of ESBLs has recently undergone a remarkable evolution in several settings, mostly due to the massive diffusion of CTX-M-type enzymes vs. the older TEM- and SHV-type ESBLs. In Italy, a large multicentre, prospective, cohort study is ongoing to assess the molecular epidemiology, clinical impact, treatment outcome and risk factors for infections caused by ESBL-producing Enterobacteriaceae. We report the preliminary results from one of the study centres, where a major evolution of the ESBL epidemiology has been observed in the past few years.

Methods: ESBL screening was carried out using modified cefotaxime and ceftazidime breakpoints, as recommended by the CLSI. ESBL production was confirmed using the combination disk test, based on CLSI methodology. ESBL determinants were investigated by PCR and sequencing. Patients with ESBL infections and matched controls were prospectively enrolled in the study. Data on risk factors, therapy and outcome were collected in an electronic database.

Results: 65 cases of infections caused by ESBL-producers observed at Florence University Hospital were studied during a 12-month period (July 2007-June 2008). The most prevalent ESBL-positive species was Escherichia coli (77%), followed by Klebsiella pneumoniae (12%). CTX-M-type enzymes accounted for 74% of the ESBL producers. The ESBL epidemiology was found to be profoundly changed in comparison with that observed in 2003, in the same centre, during a nationwide survey (E. coli and CTX-M-type enzymes accounted for 15% and 1% of the ESBL producers, respectively). Isolates were mostly from urinary and lower respiratory tract infections. Almost half (43%) of infections were from internal medicine/geriatrics wards. Previous hospitalisation and presence of urinary catheter were associated with infection with ESBLs producing Enterobacteriaceae. Empirical treatment resulted appropriate according to in-vitro susceptibility testing in 69% of the cases. Inappropriate therapy was mainly (88%) based on fluoroquinolones.

Conclusion: A recent and massive dissemination of CTX-M-producing E. coli modified remarkably the ESBL epidemiology in this hospital setting. Similar strains now pose a major clinical challenge.

Acknowledgements: Study supported by a research grant from Merck Sharp & Dohme.

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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