Pneumonia hospitalar causada por Pseudomonas aeruginosa resistente a carbapenem: fatores de risco e impacto do tratamento e da presença da metalo-beta-lactamase SPM-1 na evolução clínica

• Ano de defesa: 2008
• Autor(a) principal: Furtado, Guilherme Henrique Campos [UNIFESP]
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de São Paulo (UNIFESP)
• Palavras-chave em Português: Evolução; Fatores de risco; Polimixina; Pseudomonas aeruginosa; Resistência a antibióticos; Pneumonia hospitalar
• Link de acesso: http://repositorio.unifesp.br/handle/11600/9937

Objective: The study sought to determine the risk factors independently associated to nosocomial pneumonia due to carbapenem-resistant Pseudomonas aeruginosa in a medical-surgical ICU. The factors associated to unfavorable outcome on those patients who were treated with polymyxin B were evaluated as well as the outcome in episodes caused by strains harboring the metallo-ƒÀ- lactamase SPM-1. Methods: The study was undertaken at Hospital Sao Paulo, a university-affiliated hospital. We evaluated patients admitted to Anestesiology ICU through a case-case-control study, between 2002 and 2005. Patients with nosocomial pneumonia caused by resistant and susceptible strains were designed as resistant cases (study 1) and susceptible cases ( study 2), respectively. The controls were patients admitted to the same unit in the same period. The second study addressed the outcome of patients admitted to ICUs with nosocomial pneumonia due to carbapenem-resistant Pseudomonas aeruginosa who were treated with polymyxin B. Patients admitted to the ICUs between 1997-2005 were enrolled for the study. A nested case-control was undertaken. Cases were patients with unfavorable outcome and controls were patients with favorable outcome. The third study was undertaken through a nested case-control methodology as well. Cases were patients with nosocomial pneumonia caused by carbapenem-resistant Pseudomonas aeruginosa harboring the metalloenzyme SPM-1, and controls were patients without SPM-1. Results: 58 resistant cases, 47 susceptible cases and 237 controls were evaluated.The risk factors independently associated to nosocomial pneumonia in study 1 were: duration of hospitalization( OR 1,19 CI95%: 1,12-1,26, p< 0,001); APACHE II score(OR 1,11 CI95%: 1,01-1,22, p=0,03); male sex(OR 8,01 CI95%: 1,66-38,51, p=0,009); receipt of hemodyalisis(OR 6,85 CI95%:1,33-35,2, p=0,02); receipt of corticosteroid (OR 13,18 CI95%:3,80-45,64, p< 0,001); receipt of piperacillin-tazobactam ( OR 14,31 CI95%:1,02-200,16, p=0,04) and receipt of 3rd-generation cephalosporins( OR 7,45 CI95%: 1,80-30,86, p=0,006). The risk factors independently associated to nosocomial pneumonia caused by carbapenem-susceptible Pseudomonas aeruginosa( study 2) were: duration of ICU stay(OR 1,02 CI95%: 1,01-1,04, p= 0,004) and receipt of corticosteroid( OR 12,32 CI95%: 5,81-26,10, p< 0,001). The sole independently risk factor that was present in the two studies was the corticosteroid use. Thus, the real OR for the variable found in the study was 1,06 ( OR of study 1 divided by OR of study 2). 74 patients with nosocomial pneumonia treated with polymyxin B were evaluated. The factors associated to a unfavorable outcome were: presence of septic shock(OR 4,81 CI95%:1,42-16,25, p= 0,01) and presence of acute respiratory distress syndrome( OR 11,29 CI95%:2,64-48,22, p=0,001). 29 strains were evaluated concerning the presence of metallo-â- lactamases. Only five strains were positive for SPM-1. The presence of SPM-1 didn’t have impact on the outcome of these episodes (p=0,67). The combined treatment with polymyxin B and imipenem in patients without SPM-1 did not have positive impact on the outcome (p=0,67). None variable was independently associated to nosocomial pneumonia caused by SPM-1-positive strains. Only female sex showed a trend in univariate analysis (OR 9,71; CI95%: 0,92-103,04; p=0,05). There was no difference in outcome in episodes caused by Pseudomonas aeruginosa strains harboring SPM-1 compared to strains without SPM-1. Conclusions: The receipt of corticosteroid was the sole independently risk factor associated to nosocomial pneumonia caused by carbapenem-resistant Pseudomonas aeruginosa. The presence of septic shock and acute respiratory distress syndrome (ARDS) were the only factors related to unfavorable outcome. None variable was associated to the presence of metallo-â-lactamase SPM-1. In addition, the presence of this enzyme did not have impact on clinical outcome.