 Definition of appropriateness of Empirical therapy Empirical antibiotic therapy is defined as antibiotic given during the first 48 hours for pneumonia. The appropriateness of antibiotic therapy will be analyzed only for cases with causative organism probably and definite organisms identified. Inadequacy therapy is defined as administration of an antibiotic to which the isolated pathogen was resistant according to the subsequent antimicrobial susceptibility results or the absence of antimicrobial agents to cover the identified pathogens. In addition, patients with aspiration pneumonia Aspiration pneumonia are defined as witnessed aspiration pneumonia and food or material noted in the upper or lower airways who had not received agents with anti-anaerobic coverage will be considered inappropriate. 