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Emergence of ESBL-producing Klebsiella pneumoniae in Danish hospitals: this is in part explained by spread of one CTX-M15 clone in Zealand

Abstract number: P1251

Lester C.H., Olsen S.S., Arpi M., Fuursted K., Hansen D.S., Heltberg O., Holm A., Højbjerg T., Truberg Jensen K., Krogh Johansen H., Stenz Justesen U., Kemp M., Dahl Knudsen J., Røder B., Frimodt-Møller N., Hammerum A.M.

Objectives: The spread of resistance to third-generation cephalosporins in Klebsiella pneumoniae is a continuing cause of public health concern. Before 2007 the occurrence of third-generation cephalosporin resistance was low among K. pneumoniae isolated from bloodstream infections in Danish patients. However, the rate of resistance has increased from 4.4% in 2006 to 10.8% in 2008 (EARSS). The aim of the present study was to investigate the spread of third-generation cephalosporin resistant K. pneumoniae in Danish hospitals and to do a molecular characterisation of the collected isolates.

Methods: All Danish Departments of Clinical Microbiology were asked to send third-generation cephalosporin resistant K. pneumoniae isolated from blood in 2008 to Statens Serum Institut, Denmark. ESBL and/or AmpC phenotypes were tested using the NeoSensitabs double disk method (Rosco Diagnostica, Tåstrup, Denmark). Based on the obtained phenotypes, PCR amplification and sequencing was performed with primers specific to identify blaTEM, blaCTX_M, blaOXA, blaSHV and ampC b-lactamase genes. All ESBL and ampC positive isolates were PFGE typed. The PFGE patterns were compared using Bionumerics 6.01 (Applied Maths, Sint-Martens-Latem, Belgium).

Results: In total, 80 isolates were received: 77 isolates were ESBL positive, 2 isolates were ampC positive and 1 isolate was both ampC and ESBL positive. Among the ESBL positive isolates 47% (n = 37) belonged to the same PFGE cluster and had the genetic profile: CTX-M-15, SHV-28. The isolates in this cluster originated from eight hospitals all located in Zealand. Another cluster included nine isolates (12%) with the genetic profile CTX-M-15, SHV-1. The isolates in this cluster were all from hospitals in Copenhagen. The three ampC positive isolates were positive for the DHA-1 gene and PFGE showed that they were possibly related (>85% similarity). Among the 78 ESBL positive isolates, CTX-M-15 was detected in 64 isolates (82%); CTX-M-14 was detected in five isolates.

Conclusion: Emergence of third-generation cephalosporin resistance among K. pneumoniae in Denmark is mostly due to ESBL-producing isolates; 82% of the isolates contain CTX-M-15. Many of the isolates were clonally related (47%); these isolates were recovered from one region of the country (Zealand) indicating clonal spread within the hospitals in this region.

Session Details

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