Characterisation of PER-1 extended-spectrum b-lactamase producing P. aeruginosa clinical isolates from Hungary and Serbia

Abstract number: 1733_175

Libisch B., Lepsanovic Z., Krucso B., Muzslay M., Tomanovic B., Nonkovic Z., Mirovic V., Szabo G., Balogh B., Füzi M.

Objectives: The aim of our study was to assess the contribution of ESBLs to the MDR phenotype among P. aeruginosa clinical isolates from Hungary and Serbia and to examine their molecular epidemiology.

Methods: The double-disk synergy test was performed with cefepime, ceftazidime and amoxicillin-clavulanic acid disks on MH agar plates for phenotypic ESBL screening. The positive isolates were characterised by serotyping, RAPD and PFGE analysis and submitted to PCR reactions using blaPER, blaVEB, blaGES and class 1 integron specific primers. The full length of the coding region of the identified blaPER genes were sequenced. Mating out assays were carried out on MH agar plates and transconjugants were selected on plates containing 16 mg/l ceftazidime and 300 mg/l rifampicin using the P. putida strain UWC1 as recipient.

Results: A strain collection of MDR P. aeruginosa representing all geographical regions of Hungary and one Belgrade hospital was screened by phenotypic methods. This work yielded 4 positive P. aeruginosa isolates from the Belgrade hospital in Serbia and 2 isolates from two different hospitals in Budapest, Hungary. PCR experiments revealed the presence of blaPER genes in all six isolates and indicated that these genes are not located on class 1 integrons. Sequencing of their coding region identified the PER-1 allele in every case. All isolates belonged to serotype O11. The four positive isolates from the same Belgrade hospital are clonally related by both PFGE and RAPD thus represent a cluster of PER-1 positive infections. While macrorestriction profiling could not establish genetic relatedness between the isolates from Budapest and Belgrade using an 80% cut off value, RAPD indicated a potential clonal relationship between them with the Dice coefficients ≥ 89%. Interestingly, one of the PER-1 isolates from Budapest was cultured from the nasal swab sample of a Romanian citizen on admission to the hospital. This observation raises the possibility that this strain was imported to Hungary from abroad. The PER-1 gene proved to be transferable by in vitro conjugation experiments for both strains from Hungary.

Conclusions: This is the first report of ESBL-producing Pseudomonas spp. from Serbia and Hungary. Our results indicate that ESBL producers occur only sporadically among P. aeruginosa clinical isolates in Hungary while a cluster of PER-1 positive infections was identified in the Belgrade hospital.

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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