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Identification of a Pseudomonas putida isolate harbouring blaVIM metallo-beta lactamase gene on the hands of an intensive care unit healthcare worker

Abstract number: 1733_61

Bisiklis A., Manolopoulos K., Tomos K., Kazakos E., Isticoglou I., Alexiou-Daniel S.

Objectives: We sought to investigate the microbial flora of the hands of healthcare personnel working in Intensive Care Units in order to identify potential dissemination of carbapenemase producing-Pseudomonas spp. during routine care.

Materials and Methods: Cotton swabs were used to obtain surveillance cultures from the hands of 50 healthcare workers attached to Intensive Care Units. Each culture event was performed twice – at the beginning and at the end of their shift. Swabs were placed directly into Mueller–Hinton broth, incubated for 24 hours at 37°C in ambient air and subsequently subcultured onto blood and Mc Conkey agars followed by 18 to 24 hour-incubation under similar conditions. Initial evaluation of growth was performed by means of Gram stain for each unique colony morphotype present on cultures. Definite bacterial identification and antimicrobial susceptibility testing was achieved with the VITEK 2 identification system. Resistance to imipenem and meropenem was further confirmed by the Etest assay according to the manufacturers' instructions and data were interpreted by applying the CLSI criteria. Metallo-b-lactamase (MBL) phenotypes among resistant strains were detected with the use of Etest MBL strips. Carbapenemase-resistant isolates were subjected to PCR analysis to confirm the presence of blaVIM and blaIMP genes.

Results: During the study, two P. aeruginosa, one P. oryzihabitans and four P. putida non-duplicate isolates were recovered. Among these, one Ps. putida strain was characterised phenotypically as metallo-b-lactamase producer. PCR analysis of the latter with primers for blaVIM genes yielded a 261 bp amplicon, indicating the presence of a blaVIM allele. Interestingly, antimicrobial susceptibility testing revealed one P. aeruginosa strain that showed resistance to imipenem (MIC > 32 ug/mL) and intermediate susceptibility to meropenem (MIC = 8 ug/mL), however MBL production could not be established by both conventional and molecular assays.

Conclusion: Previous reports have demonstrated the existence of blaVIM genes in Gram-negative bacilli isolated from various contaminated sites – inanimate objects or intact patient skin surfaces – within hospital facilities. Our study provides further evidence regarding the role of healthcare personnel in multidrug-resistant strains transmission and underlines the need for continuous epidemiological surveillance, in order to assess potential reservoirs, and implementation of preventive policies.

Session Details

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