Which of the following causes highest risk of nosocomial infection to a patient -

Most common nosocomial infection → Urinary tract infection. Most of the nosocomial UTIs occur after urinary catheterization. Second most common nosocomial infection → Pneumonia. Most of the nosocomial pneumonia are acquire through respiratory intubation, mechanical ventilation and suction of the material from the mouth. Next most common cause of nosocomial infection → Surgical procedures. Surgical procedures increase a patient's risk of getting an infection in the hospital. Surgery directly invades the patient's body giving bacteria a way into normally sterile parts of the body. An infection may be acquired from contaminated surgical equipment or from health-care workers. Following surgery, the surgical wound can become infected.