Emergence of carbepenem-resistant Acinetobacter baumannii in a Bulgarian university hospital

Abstract number: 1733_838

Dobrewski R., van der Reijden T.J.K., van Strijen E., Keuleyan E., Hitkova H., Savov E., Lesseva M., van den Broek P.J., Dijkshoorn L.

Objectives: From 2000 to 2002 a predominant multidrug resistant (MDR) but carbapenem susceptible Acinetobacter baumannii strain was identified in the Military Medical Academy (MMA), a teaching hospital in Sofia, Bulgaria. Since, carbapenem resistant A. baumannii has emerged in this hospital and in other Bulgarian hospitals. The purpose of our study was to investigate whether this phenomenon was due to the spread of a single strain.

Methods: A total of 72 MDR A. baumannii isolates from 72 patients was investigated including 58 isolates from the MMA and 14 from three other hospitals (A-C). Sixty-six isolates were carbapenem resistant; six were carbapenem susceptible. The 58 MMA isolates comprised 53 carbapenem resistant and five carbepenem susceptible isolates from epidemic episodes from 2004 to 2006. The 14 isolates from the hospitals A–C were from 2005 to 2006; all but one were carbapenem resistant. Presumptive identification and antibiotic susceptibility determination was done with the VITEK 2 system (bioMérieux). AFLP analysis was used to identify the organisms at species, clone and strain level using clustering levels of 50%, 80% and 90% respectively.

Results: All isolates were identified to A. baumannii as they clustered with A. baumannii reference strains at 50% or above. At the strain delineation level of 90%, the isolates were allocated to seven clusters and a single strain, coded 1–8. Two major clusters, no. 1 and no. 7 included 47 and 11 isolates respectively. Five other clusters contained 2–4 isolates each. Eleven isolates from hospital A–C grouped together in the major cluster 1 with isolates from the MMA; three other isolates from hospital A–C were in cluster 3, 4 and 7, respectively. Thus, there was no clear correlation between AFLP clustering and the hospitals of origin. The four isolates of cluster 4 belonged to EU clone II; three were carbapenem resistant, one was susceptible. The four carbapenem resistant isolates that grouped together in cluster 5 belonged to EU clone I. None of the currently found strains corresponded to the strains found in the MMA from 2000–2002.

Conclusion: Eight different carbapenem resistant A. baumannii strains were distinguished by AFLP fingerprint analysis. Most isolates belonged to two predominant clusters and were considered to represent two major strains. In particular one strain (corresponding to AFLP cluster 1) was widely prevalent in the MMA and was also in the three other hospitals.

Session Details

Date: 31/03/2007
Time: 00:00-00:00
Session name: European Society of Clinical Microbiology and Infectious Diseases
Location: ICC, Munich, Germany
Presentation type:
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