Introductory Chapter: Pneumonia IntechOpen What is the definition of hospitalacquired pneumonia (HAP) and how does it differ from ventilatorassociated pneumonia (VAP)? CAP, HCAP, HAP and VAP Diagnosis and Treatment HCAP GrepMed Metagenomics for the microbiological diagnosis of hospital acquired pneumonia and ventilator associated pneumonia (HAP VAP) in intensive care unit (ICU): a proof of concept study Respiratory Research Springer Nature Link VAP #HAP #pneumonia The diagnosis of VAP is difficult as clinical signs suggestive of pneumonia, such as fever, tachycardia, and leukocytosis, are nonspecific in critically ill patients. Moreover, particularly in