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Predominantly clonal transmission of CTX-M-1 harbouring K. pneumoniae in two wards

Abstract number: P618

Kaase M., Anders A., Friedrich S., Schieren G., Förster T., Szabados F., Sakinc T., Kleine B., Gatermann S.G.

Objectives: Resistance against third generation cephalosporins in K. pneumoniae is an increasing problem and is mainly due to extended spectrum b-lactamases (ESBL). A worldwide increase of CTX-M-type b-lactamases has been described in recent years but epidemiologic data from Germany are scarce.

Methods: From January 2006 to April 2007 we collected 38 non-copy isolates of K. pneumoniae with an ESBL phenotype from ward A (N = 29) and B (N = 9), located in different hospitals and representing different patient populations. Typing was performed by PFGE after enzymatic DNA macrorestriction with XbaI. PCR for TEM, SHV and CTX-M was conducted in all isolates. In single representative isolates genes coding for CTX-M were sequenced. MICs of b-lactam-antibiotics were determined by Etest or microdilution, susceptibility testing for other antibiotic classes was done by agardiffusion.

Results: 15 and 3 isolates from ward A belonged to clone 1 and 2, respectively. 5 isolates from ward B (clone 3) had identical PFGE patterns. All isolates had an SHV b-lactamase as expected. TEM was found in 21 isolates, a CTX-M b-lactamase was found in 36 isolates. In 34 isolates, including all clone 1, clone 2 and clone 3 isolates, a CTX-M-1 group b-lactamase was found. A CTX-M-9 group b-lactamase was found in two isolates.

MIC50 was >256 mg/l for piperacillin, 8 mg/l for piperacillin/tazo­bactam, 6 mg/l for temocillin, >256 mg/l for cefotaxim and 128 mg/l for ceftazidim. Resistance rates against other antibiotic classes were 94.7% for ciprofloxacin, 78.9% for tobramycin, 34.2% for gentamicin, 26.3% for doxycyclin and 52.6% for sulfamethoxazol-trimethoprim.

Conclusion: Clonal transmission was the most important factor responsible for spread of CTX-M-1 group harbouring K. pneumoniae in both wards. Predominant clones were different in both locations highlighting the significance of local epidemiological studies. Temocillin and piperacillin/tazobactam retained good activity in vitro agains ESBL K. pneumoniae isolates in our area.

Session Details

Date: 19/04/2008
Time: 00:00-00:00
Session name: 18th European Congress of Clinical Microbiology and Infectious Diseases
Subject:
Location: Barcelona, Spain
Presentation type:
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