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Faecal colonisation with extended-spectrum -lactamase producing Enterobacteriaceae among patients in nine Swedish nursing homes

Abstract number: P669

Andersson M., Andersson H., Fossum B., Kalin M., Lindholm C., Örtqvist Å., Giske C.G., Iversen A.

Objectives: Extended-spectrum b-lactamase producing Enterobacteriaceae (ESBL-EB) have increased during the last years also in low-prevalence countries like Sweden, and mandatory laboratory reporting has been introduced on a national level. Little is known about the population prevalence of ESBL-EB in Sweden, and information is also largely lacking on source of the isolates (community vs hospital). The objectives of this study was to investigate the prevalence of ESBL-EB among the total population of elderly patients living in nursing homes in Solna County, north of Stockholm, Sweden.

Methods: Faecal swabs from 495 elderly living in nine nursing homes were collected during a five week period in October and November 2008 and sent for cultivation at Karolinska University Laboratory. Faecal swabs were cultured on selective chromID ESBL plates (bioMérieux). Species determination was performed with in-house biochemical tests and presence of ESBL was investigated with disks (Becton Dickinson) or Etests (bioMérieux). ESBL-producing isolates were epidemiologically characterised using pulsed-field gel electrophoresis (PFGE) when several cases were detected in the same nursing homes. A previously described real-time probe based PCR was used for typing of blaCTX-M to the phylogenetic subgroups.

Results: Fifteen of the 495 elderly living in seven of the nine nursing homes were ESBL positive (3%). The majority of the elderly were colonised with Escherichia coli (14/15), followed by Klebsiella pneumoniae that was found in two patients, one of which was co-colonised with E. coli, K. pneumoniae and Citrobacter koseri. PFGE patterns on XbaI digested DNA was analysed for eleven E. coli isolates from elderly living in four nursing homes with several cases. In two of the homes a close correlation was found between the isolates, indicating transmission between patients. PCR typing of blaCTX-M among E. coli showed that 11 belonged to CTX-M-1 subgroup, one to CTX-M-9 subgroup, and two isolates were blaCTX-M negative. Among K. pneumoniae and C. koseri all isolates were blaCTX-M negative.

Conclusion: To our knowledge this is the first population based prevalence study of ESBL-carriage in Scandinavia. In the study population 3% were colonised with ESBL-producing Enterobacteriaceae. Only a few examples of possible local transmission were documented.

Session Details

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