[Epidemic outbreak of Pseudomonas aeruginosa carbepenem-resistant producing metallo-beta-lactamase]

Abstract

Objective: To describe the nosocomial outbreak of multiresistant Pseudomonas aeruginosa producing metallo-beta-lactamase (MBL) in Cartagena (Murcia, Spain).

Material and methods: In May 2009, six consecutive isolations of multiresistant Pseudomonas aeruginosa were detected. These were characterized by their profile of resistance to imipenem and cephalosporins and sensibility to aztreonam, this suggesting the production of carbapenemases. The isolations were screened for MBL and a PCR for the detection of the VIM gene was performed. Secondary, all of the isolations having the same characteristics in the year 2009 were analyzed retrospectively in order to establish the possibility of an endemic infection.

Results: The molecular typing of the isolates revealed two clones in Pulsed Field Gel Electrophoresis (PFGE), the most frequent (Type 1) being represented by 4 isolates. All of them came from patients who were in the Intensive Care Unit. All (100%) of the isolates of the outbreak were considered to be multiresistant. PCR confirmed the presence of the VIM gene related with the production of MBL in 100% of the isolates corresponding to pulsotype 1.

Conclusions: We detected the existence of an outbreak of carbapenem-resistant Pseudomonas aeruginosa producing metallo-beta-lactamase. Am evident therapeutic problem as well as a problem of nosocomial infection was considered. The isolation means should be maximized and routine controls performed for the presence of MBL given its elevated prevalence in our setting.