Cross-transmission of Klebsiella pneumoniae in intensive care units: interhospital and intrahospital spread

Abstract number: P1309

Agodi A., Barchitta M., Valenti G., Marzagalli R., Romeo M.A., Giaquinta L., Santangelo C., Castiglione G., Tsakris A.

Objectives: In order to identify, assess and apply relevant evidence for better health care decision-making, our study was conducted to evaluate whether HCAIs due to "Klebsiella pneumoniae" in intensive care units (ICUs) originate mainly from patients' endogenous flora or from exogenous sources, by determining: i) the occurrence of "K. pneumoniae" carriage; ii) the ICU-acquired "K. pneumoniae" infection and colonization rates, by site; iii) the impact of cross-transmission using molecular typing data.

Methods: The study design integrated the patient-based and the laboratory-based surveillance approaches at the ICUs of two Italian Hospitals. Standard definitions of carriage and colonization were used. Infections were in accordance with the protocol of the Italian Nosocomial Infections Surveillance in Intensive Care Units (SPIN-UTI). Molecular typing of "K. pneumoniae" isolates was performed by macrorestriction analysis of the XbaI-digested genomic DNA. A cross-transmission episode was assumed when two patients had indistinguishable isolates.

Results: During a seven-months period, from October 2008 to April 2009, a total of 171 patients were enrolled in the study and a total of 107 isolates were collected from 51 patients. In particular, carriage was associated to 15.5% of isolates; colonization to 24.1%, infection to 23.1%, and colonization/infection accounted for the remaining 37.3% of isolates. Bloodstream infections were the most encountered (56%). Cumulative incidences of "K. pneumoniae"-sustained colonization and infections were respectively 15.2 per 100 patients and 14.6 per 100 patients. PFGE analysis of "K. pneumoniae" isolates led to the identification of a total of 27 unrelated pulse-types. Particularly, 4 clones were associated to cross-transmission and the remaining 23 were single patterns associated with sporadic strains. Two major clones were identified involving 38.3% and 22.4% of isolates, showing respectively interhospital as well as intrahospital spread. The impact of "K. pneumoniae" cross-transmission was estimated to be at least 56.5%, thus defining the exogenous preventable proportion of all cross-transmission episodes.

Conclusion: Our data underline the impact of "K. pneumoniae" in the ICU settings and highlight the need of appropriate epidemiologic investigations to trace sources and transmission routes in order to provide evidences to address screening at admission and other control policies.

Session Details

Date: 10/04/2010
Time: 00:00-00:00
Session name: Abstracts 20th European Congress of Clinical Microbiology and Infectious Diseases
Location: Vienna, Austria, 10 - 13 April 2010
Presentation type:
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