Risk Factors for 7-Day and 21-Day Mortality in Patients with Ventilator-Associated Pneumonia Caused by Gram-Negative Multidrug Resistant Bacteria

Objective: Incidence of ventilator-associated pneumonia, caused by gram-negative multidrug resistant bacteria, is on the increase and early mortality rate is high. 
We aimed to investigate the effects of aging, comorbidities, high Charlson comobidity index score, high Acute Physiology and Chronic Health Evaluation II score, leukocytosis, high C-reactive protein level, inappropriate empirical antibiotic therapy and antibiotic resistance on mortality in ventilator-associated pneumonia caused by gram-negative multidrug-resistant bacteria. 
Methods: The study was planned as a retrospective cohort study. Patients aged 18 years and older who were hospitalized between January 01, 2015, and January 01, 2020, diagnosed with ventilator-associated pneumonia, and had Gram-negative multidrug resistant pathogen was detected in blood and/or bronchoalveolar lavage fluid specimen or quantitative endotracheal aspirate cultures were included in the study. 
Results: A total of 370 patients were included in the study. Median age of the patients was 74 (19-95) years. Most frequent bacteria was Acinetobacter baumannii (52.4%). Resistance to ceftriaxone, meropenem, and colistin was 99%, 68%, and 4%, respectively. 7-day and 21-day mortality rates were 38.3% (n=142) and 85.1% (n=315). In multivariate analysis, 7-day mortality was associated with a Charlson comorbidity index score of ≥4, and risk factors for 7-day mortality were septic shock, amikacin resistance, and white blood cell count ≥15000/mm3. Advanced age was found to be a risk factor for 21-day mortality, and a high Acute Physiology and Chronic Health Evaluation II score and a high Charlson comorbidity index score were associated with 21-day mortality. It was found that the risk of 7-day mortality in patients with tracheostomy was lower than in patients without tracheostomy. 
Conclusion:Consideration of clinical scoring systems, closer monitoring of elderly patients, following-up with tracheostomy, may provide a decrease in mortality of ventilator-associated pneumonia, caused by multidrug resistant pathogens.