Ventilator-Associated Pneumonia due to Drug-Resistant Acinetobacter baumannii: Risk Factors and Mortality Relation with Resistance Profiles, and Independent Predictors of In-Hospital Mortality

Abstract

<i>Background and objectives:</i> High mortality and healthcare costs area associated with ventilator-associated pneumonia (VAP) due to <i>Acinetobacter baumannii</i> (<i>A. baumannii</i>). The data concerning the link between multidrug-resistance of <i>A. baumannii</i> strains and outcomes remains controversial. Therefore, we aimed to identify the relation of risk factors for ventilator-associated pneumonia (VAP) and mortality with the drug resistance profiles of <i>Acinetobacter baumannii</i> (<i>A. baumannii</i>) and independent predictors of in-hospital mortality. <i>Methods:</i> A retrospective ongoing cohort study of 60 patients that were treated for VAP due to drug-resistant <i>A. baumannii</i> in medical-surgical intensive care units (ICU) over a two-year period was conducted. <i>Results:</i> The proportions of multidrug-resistant (MDR), extensively drug-resistant (XDR), and potentially pandrug-resistant (pPDR) <i>A. baumannii</i> were 13.3%, 68.3%, and 18.3%, respectively. The SAPS II scores on ICU admission were 42.6, 48.7, and 49 (<i>p</i> = 0.048); hospital length of stay (LOS) prior to ICU was 0, one, and two days (<i>p</i> = 0.036), prior to mechanical ventilation (MV)-0, 0, and three days (<i>p</i> = 0.013), and carbapenem use prior to VAP-50%, 29.3%, and 18.2% (<i>p</i> = 0.036), respectively. The overall in-hospital mortality rate was 63.3%. In MDR, XDR, and pPDR <i>A. baumannii</i> VAP groups, it was 62.5%, 61.3%, and 72.7% (<i>p</i> = 0.772), respectively. Binary logistic regression analysis showed that female gender (95% OR 5.26; CI: 1.21⁻22.83), SOFA score on ICU admission (95% OR 1.28; CI: 1.06⁻1.53), and RBC transfusion (95% OR 5.98; CI: 1.41⁻25.27) were all independent predictors of in-hospital mortality. <i>Conclusions:</i> The VAP risk factors: higher SAPS II score, increased hospital LOS prior to ICU, and MV were related to the higher resistance profile of <i>A. baumannii</i>. Carbapenem use was found to be associated with the risk of MDR <i>A. baumannii</i> VAP. Mortality due to drug-resistant <i>A. baumannii</i> VAP was high, but it was not associated with the <i>A. baumannii</i> resistance profile. Female gender, SOFA score, and RBC transfusion were found to be independent predictors of in-hospital mortality.