Comparative Clinicomicrobiological Profile, Risk Factors, and Outcomes of Patients with and without Ventilator Associated Pneumonia: A Retrospective Observational Study from a Tertiary Care Hospital in Northern India

Introduction: Ventilator Associated Pneumonia (VAP) is a common Healthcare Associated Infection (HAI) in mechanically ventilated patients, leading to increased morbidity, mortality, Intensive Care Unit (ICU) stays, and healthcare costs. VAP is most commonly caused by Gram negative, non fermenting bacteria notably Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacterales such as Klebsiella pneumoniae all of which frequently exhibit Multidrug Resistance (MDR), making treatment challenging. Timely diagnosis followed by appropriate, targeted antibiotic therapy is critical in improving patient outcomes. Aim: To evaluate and compare the clinicomicrobiological profile, risk factors, and clinical outcomes of VAP and Non VAP patients admitted to a tertiary care hospital in Northern India. Materials and Methods: This retrospective, laboratory-based observational study was conducted in the Department of Microbiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences (SGPGIMS), Lucknow, Uttar Pradesh, India from March 2024 to August 2024. The study included adult patients admitted to ICU and managed on mechanical ventilation, who fulfilled the predefined inclusion criteria for VAP. A total of 243 respiratory samples were analysed during the study period. The methodology involved collection and microbiological processing of Endotracheal (ET) aspirates and bronchoalveolar lavage samples, followed by organism identification and antimicrobial susceptibility testing as per standard guidelines. Demographic parameters such as age and sex were recorded. Statistical analysis was performed using appropriate tests, including the Chi-square test or Fisher’s exact test for categorical variables and the Student’s t-test or Mann-Whitney U test for continuous variables, with a p-value of <0.05 considered statistically significant. Results: Of the 243 respiratory samples, 197 (81.07%) samples were obtained through ET aspirates, while remaining 46 (18.93%) were BAL fluid. VAP was diagnosed in 68 (27.98%) patients, while 175 (72.02%) patients were identified as not having VAP. The incidence of VAP was 36.28 per 1000 ventilator days. Among risk factors, supine head position, tracheostomy, total days on MV, length of stay in hospital, re-intubation were significantly higher in VAP group. Among the 68 patients diagnosed with VAP, only 65 had culture-positive samples. Of these 65 isolates, 53 (81.53%) were caused by Gram-negative bacilli (GNB). Of them A. baumannii 13 (20%) was the commonest, followed by P. aeruginosa 11 (16.92%) and K. pneumoniae 10 (15.38%). Among, Gram-positive cocci (GPC) 12 (18.46%), Methicillin-resistant Staphylococcus aureus (MRSA) 9 (13.84%) was the commonest followed by E. faecium 3 (4.61%). Conclusion: The incidence of VAP was high in the present study. Mortality rate was slightly higher in VAP group, it was not statistically significant. A. baumannii and P. aeruginosa are emerging MDR nosocomial pathogens. Therefore, accurate species identification and AST are essential for improving patient outcomes.