Legionnaires' disease acquired its name in July 1976, when an outbreak of pneumonia occurred among people attending a convention of the American Legion at the Bellevue-Stratford Hotel in Philadelphia. Of the 182 reported cases, mostly men, 29 died. On January 18, 1977, the causative agent was identified as a previously unknown strain of bacteria, subsequently named "Legionella", and the species that caused the outbreak was named "Legionella pneumophila". Outbreaks of Legionnaires' disease receive significant media attention, but this disease usually occurs in single, isolated cases not associated with any recognized outbreak. When outbreaks do occur, they are usually in the summer and
Hospital-acquired pneumonia day case for regular hemodialysis or intravenous infusion (for example, chemotherapy). Especially in the very old and in demented patients, HCAP is likely to present with atypical symptoms. Among the factors contributing to contracting HAP are mechanical ventilation (ventilator-associated pneumonia), old age, decreased filtration of inspired air, intrinsic respiratory, neurologic, or other disease states that result in respiratory tract obstruction, trauma, (abdominal) surgery, medications, diminished lung volumes, or decreased clearance of secretions may diminish the defenses of the lung. Also, poor hand-washing and inadequate disinfection of respiratory devices cause cross-infection and are important factors. Most nosocomial respiratory infections are caused