title: Nosocomial infections with metallo-beta-lactamase-producing Pseudomonas aeruginosa: molecular epidemiology, risk factors, clinical features and outcomes.
abstract: BACKGROUND
  Metallo-β-lactamases (MBLs) have emerged as one of the most important bacterial resistance mechanisms because of their ability to hydrolyse virtually all β-lactam agents. MBL-producing Pseudomonas aeruginosa (MBL-PA) are an important cause of nosocomial infections, particularly in intensive care units (ICUs), where they are associated with serious infections and present a significant clinical risk.
  
  
  OBJECTIVE
  To assess the molecular epidemiology, risk factors and outcomes of nosocomial infections caused by MBL-PA in a teaching hospital in Southern Brazil.
  
  
  METHODS
  From January 2001 to December 2008, 142 carbapenem-resistant P. aeruginosa strains were isolated from distinct clinical samples from hospitalized patients. These isolates were screened for MBLs, and underwent polymerase chain reaction, sequencing and pulsed-field gel electrophoresis (PFGE). Patients infected with carbapenem-resistant MBL-PA were considered as cases, and patients infected with non-MBL-PA were considered as controls.
  
  
  RESULTS
  Eighty-four of 142 patients with positive carbapenem-resistant P. aeruginosa cultures met the criteria of the Centers for Disease Control and Prevention for infection. Fifty-eight patients were infected with MBL-PA (69%) and 26 patients were infected with non-MBL-PA (31%). Multi-variate analysis revealed that ICU stay [P = 0.003, odds ratio (OR) 4.01, 95% confidence interval (CI) 1.15-14.01] and urinary tract infection (P = 0.001, OR 9.67, 95% CI 1.72-54.48) were important risk factors for MBL-PA infection. Patients infected with MBL-PA showed faster onset of infection (P = 0.002) and faster progression to death (P = 0.04).
  
  
  CONCLUSIONS
  These results showed the severity of MBL-PA infections, and demonstrated the urgent need for strategies to improve infection control measures to prevent an increase in these nosocomial infections.
authors.affiliation: Postgraduate Programme in Internal Medicine and Health Sciences, Universidade Federal do Paraná, Curitiba, Brazil.
authors.forename: A
authors.initials: A
authors.lastname: Lucena
authors.affiliation: Bacteriology Laboratory, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil; Faculdades e Instituto de Pesquisa Pelé Pequeno Príncipe, Curitiba, Paraná, Brazil.
authors.forename: L M
authors.initials: LM
authors.lastname: Dalla Costa
authors.affiliation: Bacteriology Laboratory, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil.
authors.forename: K S
authors.initials: KS
authors.lastname: Nogueira
authors.affiliation: Laboratório Alerta, Universidade Federal de São Paulo, Brazil.
authors.forename: A P
authors.initials: AP
authors.lastname: Matos
authors.affiliation: Laboratório Alerta, Universidade Federal de São Paulo, Brazil; Laboratório Especial de Microbiologia Clínica, Division of Infectious Diseases, Universidade Federal de São Paulo, Brazil.
authors.forename: A C
authors.initials: AC
authors.lastname: Gales
authors.affiliation: Serviço de Controle de Infecção Hospitalar, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil.
authors.forename: M C
authors.initials: MC
authors.lastname: Paganini
authors.affiliation: Serviço de Controle de Infecção Hospitalar, Hospital de Clínicas, Universidade Federal do Paraná, Curitiba, Brazil.
authors.forename: M E S
authors.initials: ME
authors.lastname: Castro
authors.affiliation: Postgraduate Programme in Internal Medicine and Health Sciences, Universidade Federal do Paraná, Curitiba, Brazil. Electronic address: sraboni@ufpr.br.
authors.forename: S M
authors.initials: SM
authors.lastname: Raboni
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001426:Bacterial Proteins / Q000378:metabolism*; D001938:Brazil / Q000453:epidemiology; D016022:Case-Control Studies; D002648:Child; D003428:Cross Infection / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology* / Q000517:prevention & control; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D016521:Electrophoresis, Gel, Pulsed-Field; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D017053:Infection Control / Q000379:methods; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011552:Pseudomonas Infections / Q000453:epidemiology* / Q000382:microbiology / Q000473:pathology* / Q000517:prevention & control; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D012189:Retrospective Studies; D012307:Risk Factors; D017422:Sequence Analysis, DNA; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult; D001618:beta-Lactamases / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Metallo-β-lactamase; Nosocomial infections; Pseudomonas aeruginosa