W04 Case Study: Gram-Positive and Gram-Negative BacteriaOne of the biggest challenges facing healthcare professionals today is the rapid spread of bacterial infections acquired during a hospital stay. These are known as “nosocomial” infections or HAIs (hospital acquired infections). According to the Centers for Disease Control, “HAIs affect 5 to 10 percent of hospitalized patients in the U.S. per year. Approximately 1.7 million HAIs occur in U.S. hospitals each year, resulting in 99,000 deaths and an estimated $20 billion in healthcare costs.” () Two bacteria that are associated with nosocomial infections are Staphylococcus aureusandPseudomonas aeruginosa. These two bacteria are the most common causes of ventilator associated pneumonia (VAP). This infection generally occurs about 48 hours after intubation andmechanical ventilation. The microbes enter the lungs through the tubes of the ventilator. The risk of developing pneumonia after ventilation is increased 6 to 20 fold.