Pathogenesis, Diagnosis and Therapeutic Strategies for Ventilator-associated Pneumonia

Ventilator-associated pneumonia (VAP) is a major health care associated infection which usually emanates from aspiration, immigration of pathogens from aerodigestive tract, adulterated appliance uses or medications. The mortality rate due to VAP is approximately 13% and the causative organisms are bacteria, viruses, and fungi. Many studies have investigated the causative organisms as Pseudomonas spp., Acinetobacter spp., Escherichia coli, Klebsiella pneumoniae, and Staphylococcus aureus with varying prevalence. Intensive Care Unit (ICU) admitted patients who are ventilated, are more prone to the infections where the pathogens adhere to the mucosa of lower respiratory tract of mechanically ventilated patients and start infections. Clinical diagnosis based on Clinical Pulmonary Infection Score (CPIS) has poor specificity and microbiological findings takes 48-72 hrs, that can delay the treatment of patients. Lymphopenia on complete blood count is a predictor of mortality in VAP patients, but decreased lymphocyte count occurs in various other infections too. Multiplex PCR is a better diagnostic technique for VAP which can even diagnose atypical bacteria along with other etiological agents. Effectively employing sampling techniques is a vital step in the diagnosis of VAP, enabling the identification of pathogens responsible for lung infections. Furthermore, the emergence of novel therapeutic options approved by regulatory bodies, adds significant advancements in VAP treatment. In this review article, we have performed an in-depth study on the pathogenesis, diagnosis and therapeutic strategies involved in VAP. This study will help the researchers working in this area to design their work appropriately with the updated knowledge on VAP.