**3. Epidemiology**

From 1930s, prior to the discovery of antibiotic, till date pneumonia remains the major cause of death among all age groups accounting for four million deaths annually. The rate of death is highest among children aged less than 5 years worldwide [5]. According to a study conducted by Farooqui et al. [6], 3.6 million (3.3–3.9 million) episodes of severe pneumonia and 0.35 million (0.31–0.40 million) all-cause pneumonia deaths occurred in children younger than 5 years in India. Furthermore, 0.56 million (0.49–0.64 million) severe episodes of pneumococcal pneumonia and 105,000 (92,000–119,000) pneumococcal deaths occurred in India. According to American Thoracic Society/Infectious Diseases Society of America (ATS/IDSA), 2005, HAP had a crude mortality rate of 30–70% with an estimated attributable mortality rate to pneumonia between 27 and 50%. According to some estimates, VAP contributes up to 50–85% of all cases of nosocomial pneumonia [7, 8]. Furthermore, it mainly occurs in intensive care unit (ICU) patients where they most often require ventilator support, amounting to 9–27% of all mechanically ventilated patients [8]. It is estimated that four million cases of CAP occur annually in the United States, of which 20–25% are severe enough to warrant hospitalization [9]. Pneumonia is responsible for about 1.6 million deaths among children aged <5 years in Africa and South-East Asia regions [10, 11]. HAP and VAP are important causes of mortality and morbidity, which continue to baffle the treating physicians in today's era of MDR.
