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

• Published in: Journal of antimicrobial chemotherapy Vol. 56; no. 6; pp. 1148 - 1151
• Main Authors: Zavascki, Alexandre Prehn, Gaspareto, Patrick Barcelos, Martins, Andreza Francisco, Gonçalves, Ana Lúcia, Barth, Afonso Luís
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-12-2005
• Subjects: antibiotic resistance; Antibiotics. Antiinfectious agents. Antiparasitic agents; Biological and medical sciences; carbapenems; Medical sciences; nosocomial infections; P. aeruginosa; Pharmacology. Drug treatments; Pseudomonas aeruginosa; β-lactamases; South America; Brazil; America; Pseudomonadales; Epidemic; Nosocomial infection; Teaching hospital; Enzyme; carbapenems; β-Lactamase; Resistance; Antibiotic; Carbapenem derivatives; antibiotic resistance; Bacteria; Hydrolases; Pseudomonadaceae; Pseudomonas aeruginosa; nosocomial infections; Hospital; Antibacterial agent; Public health; P. aeruginosa; p-lactamases
• ISSN: 0305-7453; 1460-2091
• DOI: 10.1093/jac/dki390

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.