Advanced age, debilitation, NG tube feedings, impaired gag reflex, poor oral hygiene, - level of consciousness, immobility, smoking, close living quarters (mycoplasma pneumonia), multiple medical comorbidities, residency in long term facility, antibiotic abuse, prolonged intubation, anesthesia, health care provider transmission, alcoholism, immunosuppressive therapy, exposure to child who attends day care setting.