Comparação de tempo de tratamento antimicrobiano curto versus longo para infecções de corrente sanguínea causadas por Pseudomonas spp. ou Acinetobacter spp.
Introdução: As bactérias gram-negativas são as principais responsáveis por infecções de corrente sanguínea em diversas partes do mundo. A duração ideal de terapia antimicrobiana para essas infecções não está bem definida, especialmente para bactérias não fermentadoras, como Acinetobacter spp. e Pseudomonas spp. O objetivo desse estudo é avaliar mortalidade em 30 dias, mortalidade intra-hospitalar, impacto no tempo de internação e erradicação microbiológica em bacteremias por Acinetobacter spp. ou Pseudomonas spp. tratadas com terapia antimicrobiana curta (≤7 dias) versus longa (>7 dias). Métodos: Conduzimos uma coorte retrospectiva de janeiro de 2014 a outubro de 2019 em dois hospitais universitários em Porto Alegre, Brasil. Foram incluídos pacientes com idade ≥18 anos, com bacteremia por Pseudomonas spp. ou Acinetobacter spp. Foram excluídos pacientes com infecções polimicrobianas, tratamento com antibióticos não suscetíveis in vitro, infecções complicadas (endocardite, osteomielite e abscessos viscerais), mortalidade precoce (7 days) antimicrobial therapy. Methods: We conducted a retrospective cohort study from January 2014 to October 2019 in two university hospitals in Porto Alegre, Brazil. Were included patients aged ≥18 years with bacteremia caused by Pseudomonas spp. or Acinetobacter spp. Patients with polymicrobial infections, treatment with non-susceptible antibiotics in vitro, complicated infections (endocarditis, osteomyelitis and visceral abscesses), early mortality (<7 days) and previous episodes of bacteremia by these bacteria in less than 30 days were excluded. Demographic variables, comorbidities, primary site of infection, disease severity and duration of therapy were evaluated. We performed a univariate analysis comparing long versus short therapy groups and assessing risk factors for mortality. Variables with P <0.2 were included in a Cox regression analysis and were retained in the model if P <0.05. We performed a subgroup analysis for carbapenem-resistant infections and for Pseudomonas spp. and Acinetobacter spp. separately. Results: Two hundred and fifty-three episodes of bacteremia were included in the final analysis: 49% were male, with a median age of 61.3±16.3 years, with 51.4% caused by Acinetobacter spp. and 48.6% by Pseudomonas spp. The median treatment time was 6 days (5 - 7) in the short treatment group and 12 days (10 - 14) in the long treatment group. Thirty-day mortality occurred for 17 (24.28%) versus 44 (24.04%) of patients treated with short versus long therapy, respectively, P=0.99. In multivariate analysis, short therapy was associated as an independent risk factor for 30-day mortality (aHR 2.04, 95% CI 1.14 – 3.65, P=0.02), when adjusted for Pitt score (aHR 1.13, 95% CI 1.05 – 1.22, P <0.01), Charlson (aHR 1.17, 95% CI 1.07 – 1.29, P <0.01) and resistance to carbapenems (aHR 2.34, 95% CI 1.32 – 4.47, P=0.01). In-hospital mortality occurred for 20 (28.5%) versus 69 (37.7%) of patients treated with short versus long-term therapy, respectively, P=0.19. In multivariate analysis, short therapy was not associated with increased risk of in-hospital mortality (aHR 1.27, 95% CI 0.76 – 2.12, P=0.35), when adjusted for Pitt score (aHR 1.10, 95% CI 1.04 – 1.18, P <0.01), Charlson (aHR 1.12, 95% CI 1.04 – 1.21, P <0.01) and carbapenem resistance (aHR 1.88, 95% CI 1.11 – 3.17, P=0.02). Of the 253 episodes of bacteremia, in 164 (63.2%) survived. Median time to hospital discharge after bloodstream infection was 9 (6 - 13) days versus 12 (8.5 - 19.5) days in the short and long therapy groups, respectively, P=0.01. Isolation of the same bacteria occurred in 26 (18.6%) of the 140 who had a new blood culture collected in 30 days: 5 (16.1%) in the short therapy group versus 21 (19.3%) in the long therapy group, P=0.80. In subgroup analysis for carbapenem-resistant bacteria, short-term therapy was not associated with higher 30-day (aHR 1.8, 95% CI 0.93 – 3.46, P=0.08) and in-hospital mortality (aHR 1.15, 95% CI 0.63 – 2.1, P=0.64), when adjusted for Charlson and Pitt score. In the bacterial subanalysis, in Acinetobacter spp. infections, short therapy was associated with higher 30-day mortality (aHR 2.31, 95% CI 1.11 – 4.81, P=0.03) but it was not associated with higher in-hospital mortality (aHR 1.27, 95% CI 0.65 – 2.48, P=0.48). As for infections caused by Pseudomonas spp., short therapy was not associated with higher 30-day (aHR 1.57, 95% CI 0.60 – 4.1, P=0.36) and in-hospital mortality (aHR 1.05, 95% CI 0.43 – 2.56, P=0.91), when adjusted for Pitt score, Charlson and carbapenem resistance. Conclusion: Short therapy was associated with higher 30-day mortality for patients with Acinetobacter spp. and Pseudomonas spp., but there was no association with higher in-hospital mortality or difference in microbiological eradication rates within 30 days. Of the surviving patients, short therapy was associated with a shorter length of hospital stay. In subgroup analysis, short therapy was associated with higher 30-day mortality in infections caused by Acinetobacter spp., regardless of sensitivity to carbapenems. Increased mortality in 30 days was not observed in Pseudomonas spp. infections, when evaluated separately. Therefore, caution is required when using short-term therapies in bloodstream infections caused by Acinetobacter spp
