Evaluation of clinical and microbiological results in ventilator-associated pneumonia due to Acinetobacter baumannii and determination of factors affecting the outcome

Objectives: Ventilator-associated pneumonia (VAP) is among the common nosocomial infections. A.baumannii causes VAP outbreaks, especially in intensive care units. It was aimed to determine the risk factors of VAP patients caused by A.baumannii, antibiotic resistance rates, and the clinical and microbiological responses of treatments. Materials and methods: In this study, 109 patients who grew A.baumannii in their respiratory tract samples and were diagnosed with VAP in the intensive care units of OMÜTF Hospital between January 2017 and December 2022 were retrospectively examined. The demographic characteristics, clinical characteristics, laboratory parameters and treatment responses of the patients were evaluated. For clinical response, all-cause 14- and 28-day mortality of patients was taken into consideration. Results: The average age of the patients included in the study was found to be 62.28 ± 17.13. The 14-day mortality of the patients included in the study was 44% and the 28-day mortality was 56%. Factors affecting both 14- and 28-day mortality in univariate analysis are age, presence of underlying comorbid disease, presence of chronic lung disease, steroid use, presence of septic shock at diagnosis, and high APACHE II and SOFA scores. In multivariate analysis, male gender, presence of chronic lung disease, pre-treatment WBC count and high APACHE II score were found to be independent risk factors in terms of mortality. Colistin resistance was found to be 8.7% in the isolated A.baumannii strains. Blood CRP and procalcitonin values were significantly higher on days 3 and 7 in patients who died. With the ROC analysis, the threshold values determined for CRP and PCT were determined to be respectively 160 and 0.65 and it was found that they could predict mortality with low sensitivity. Conclusion: A.baumannii is highly resistant to current antibiotics, there is an urgent need for effective treatments. In order to prevent the spread of A.baumannii and not to increase the resistance rate, infection control measures must be taken meticulously and rational antibiotics must be used. Keywords: Acinetobacter baumannii, Pneumonia, Mortality