Risk Factors, Sources, and Outcomes of Acinetobacter baumannii Bloodstream Infections: Insights From a Case–Control Analysis

CONTEXT: Acinetobacter baumannii bloodstream infections (BSIs) are associated with high morbidity and mortality with the need to identify clinical risk factors. AIMS: To evaluate risk factors for A. baumannii BSIs and compare risk factors and outcomes between affected patients and controls. SETTINGS AND DESIGN: A retrospective case-control study was conducted at a tertiary care hospital in southern India from January 2024 to December 2024. SUBJECTS AND METHODS: Thirty-two blood culture-positive A. baumannii BSI cases were compared with 56 matched controls (non-Acinetobacter BSI). Demographics, comorbidities, intensive care unit stay, invasive procedures, device use, antibiotic exposure, and clinical outcomes were noted from hospital records. STATISTICAL ANALYSIS USED: Categorical variables were expressed as frequencies, continuous variables as mean ± standard deviation. Chi-square test and multivariate logistic regression were performed using Jamovi software. RESULTS: Surgical intervention during the current admission emerged as an independent predictor of A. baumannii BSI (adjusted odds ratio 3.44, P < 0.05). Male gender and hypertension showed trends toward increased risk. Skin/soft-tissue (31.3%) and respiratory infections (34.4%) were the most common sources. Endotracheal intubation and high-acuity procedures were more frequent among cases. Median hospital stay was longer in cases (10 vs. 8 days), with higher mortality (31.3% vs. 14.3%). CONCLUSIONS: A. baumannii BSIs were more common in males, with hypertension noted as a frequent comorbidity. Surgery during the current admission was the strongest independent risk factor, and respiratory or skin/soft-tissue infections were the main suspected sources. These infections led to longer hospital stays and higher mortality, emphasizing the need for strict surveillance, improved infection-control practices, and careful management of invasive procedures to reduce risk and improve outcomes.