Patients in ICU with suspected or proven pneumonia (CAP/HAP/VAP) will be considered for recruitment into the study. Patients who meet the inclusion criteria will be recruited in after written informed consent. Patients will be treated according to the standard of care in accordance with international guidelines ^{[6, 10]}. Respiratory tract samples will be collected and sent for Gram stain and semi-quantitative bacterial cultures and the multiplex PCR (BioFire^® Filmarray^®Pneumonia Panel) as per the orders of the primary treating physician. Respiratory samples may be non invasive (sputum) or invasive (BAL/endotracheal aspirate).  Respiratory samples will be transported to the microbiological laboratory within a time frame of 1 hour. Low quality samples containing 10 or more epithelial cells per low power field and <25 pus cells per low power field will be rejected. 

Other microbiological investigations such as S. pneumoniae and L. pneumophilia urine antigen assays, antibody blood testing with respiratory tract sample PCR for Chlamydia pneumonia and Mycoplasma pneumonia, respiratory tract sample PCR for Influenza will be done as per the requirements. Additional microbiological samples such as blood cultures, urine cultures, CSF cultures, pleural fluid cultures etc may be performed at the clinician’s discretion. All other biochemical and radiological investigations will be performed at the clinician’s discretion. All microbiological samples will be processed in the microbiology laboratory of our institute. 

Baseline SOFA, APACHE II and CPIS (in patients with VAP) will be calculated for all patients included in the study, at the time of inclusion into the study. Turnaround time for BioFire^® Filmarray^® Pneumonia Panel is the time interval between the receipt of sample at microbiology laboratory and the receipt of results. The FilmArray^® PP results will be considered concordant if they are consistent with the results of cultures. Otherwise, the results of FilmArray^® PP will be considered discordant.

A positive match of the Gram stain result with the result of FilmArray^® PP will be considered concordant and the results will be considered discordant otherwise.

The data will be recorded in the proforma  and used for statistical analysis.