Colistin Dosage without Loading Dose Is Efficacious when Treating Carbapenem-Resistant Acinetobacter baumannii Ventilator-Associated Pneumonia Caused by Strains with High Susceptibility to Colistin

Abstract

ObjectivesThis study aims to analyze the mortality and the length of ICU stay (LOS) of A. baumannii VAP compared to respiratory colonization in patients with mechanical ventilation (MV).MethodsA prospective cohort study was performed in an ICU of adult patients (February 2010–June 2011). One hundred patients on MV with A. baumannii in lower respiratory airways were recruited, and classified as VAP or airways colonization according to CPIS criteria, with a punctuation ≥6. LOS, 30-days mortality, A. baumannii bacteremia, and clinical features including antibiotic therapy were recorded. Multivariate analysis (linear and Cox regression) and survival analysis (Kaplan-Meier curves) were performed.ResultsFifty-seven VAP and 43 colonized A. baumannii patients were analyzed. Among the A. baumannii strains, 99% were non-susceptible to carbapenems and the MIC90 of colistin was 0.12 mg/l. Therapy was appropriate in 94.6% of VAP patients, most of them with colistin 6 MIU/day, although in 13 (23.6%) cases colistin was started 48 hours after the onset of VAP. Mortality was similar in both groups (VAP 24.6% vs. colonized 27.9%, p = 0.7). Bacteremia and acute kidney insufficiency were associated with decreased survival (p = 0.02 and p = 0.04, respectively) in VAP patients. LOS was 21.5 (11.5–42.75) vs. 9 (6–22) days for VAP and colonized patients (p = 0.004). VAP (p = 0.003) and age (p = 0.01) were independently related to a longer LOS.ConclusionsMultidrug-resistant A. baumannii VAP treated with colistin does not have a different mortality compared to lower airways colonization, among patients on mechanical-ventilation, in a setting of high susceptibility to colistin of A. baumannii.

Clinical outcomes and nephrotoxicity of colistin loading dose for treatment of extensively drug-resistant <em>Acinetobacter baumannii</em> in cancer patients

“…These results were not significantly different, perhaps because the minimal inhibitory concentration in our study was low (0.064–1.5) in both groups. These results were supported by Álvarez-Marín et al 15 who showed that non-loading dose of colistin was effective for treating CRAB ventilator-associated pneumonia caused by strains with high susceptibility to colistin. 15 …”

Predictors of mortality in patients infected with carbapenem-resistant Acinetobacter baumannii: A systematic review and meta-analysis

“…The remaining 98 full-text articles were assessed for eligibility. Nineteen studies [11][12][13]19,20,[23][24][25][26][27][28][29][30][31][32][33][34][35][36] were included in the systematic review based on the inclusion and exclusion criteria. The detailed process of search and selection is shown in Fig 1.…”

Choice of therapeutic interventions and outcomes for the treatment of infections caused by multidrug-resistant gram-negative pathogens: a systematic review

“…We identified 22 studies, 16 of which were observational studies [44–59], five were randomized clinical trials [60–64], and one was systematic review and meta-analysis [65] (Table 2). The studies were based on populations with different sites of infection (airways, bloodstream, abdomen, skin, and meninges) and study population size varying from 10 to 250 patients.…”

“…In addition, the studies were often based on small sample sizes, reducing the ability to find any effect difference and to consider confounder adjustment and multivariate regression analysis. Only a few studies [24, 25, 34, 36, 40, 44, 47, 51, 52, 54, 55, 64] presented a sample size estimation and adhered to it.…”