Journal Article

Outbreak of carbapenem-resistant <i>Pseudomonas aeruginosa</i> producing SPM-1 metallo-β-lactamase in a teaching hospital in southern Brazil

Alexandre Prehn Zavascki, Patrick Barcelos Gaspareto, Andreza Francisco Martins, Ana Lúcia Gonçalves and Afonso Luís Barth

in Journal of Antimicrobial Chemotherapy

Published on behalf of British Society for Antimicrobial Chemotherapy

Volume 56, issue 6, pages 1148-1151
Published in print December 2005 | ISSN: 0305-7453
Published online October 2005 | e-ISSN: 1460-2091 | DOI:
Outbreak of carbapenem-resistant Pseudomonas aeruginosa producing SPM-1 metallo-β-lactamase in a teaching hospital in southern Brazil

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Objectives: To describe the first nosocomial outbreak of Pseudomonas aeruginosa producing SPM-1 metallo-β-lactamase (MBL) in southern Brazil.

Patients and methods: From January to October 2004, carbapenem-resistant P. aeruginosa (CRPA) were recovered from hospitalized patients. Mortality, site of infection/colonization, patient location and susceptibility profiles were analysed. A sample of CRPA was screened for MBL production, evaluated for the presence of blaSPM-1, blaIMP-1 and blaVIM-2 genes by PCR and submitted for molecular typing by DNA macrorestriction.

Results: A total of 135 CRPA (one isolate per patient) were recovered. Two major antibiotic susceptibility profiles comprised 63.7% of the isolates (susceptibility to polymyxin B and aztreonam, and susceptibility only to polymyxin B). Thirty-five CRPA were screened for MBL production (10 isolates from April, June and July, and 25 from September and October) and 27 (77.1%) proved to be positive for MBL production. Twenty-one of the 24 CRPA tested carried the blaSPM-1 gene. The mortality of patients with CRPA was 48.1% and no variable was associated with death. Molecular typing revealed the presence of a clone with four related subtypes among the blaSPM-1-positive CRPA.

Conclusions: The prevalence of MBL production by CRPA is high and horizontal transmission is a major determinant for the spread of SPM-1 CRPA among patients in this institution. As infection control measures failed to control the spread of CRPA, continuous surveillance for MBL production is warranted.

Keywords: P. aeruginosa; β-lactamases; antibiotic resistance; carbapenems; nosocomial infections

Journal Article.  1997 words. 

Subjects: Medical Oncology ; Critical Care

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