PGCEE MDS 2022: Most common mode of transmission in nosocomial infections is by:

 # Most common mode of transmission in nosocomial infections is by:

A. Contact transmission

B. Droplet transmission

C. Airborne transmission

D. Vector borne transmission

The correct answer is A. Contact transmission.

A hospital-acquired infection, also known as a nosocomial infection (from the Greek nosokomeion, meaning "hospital"), is an infection that is acquired in a hospital or other health care facility. To emphasize both hospital and nonhospital settings, it is sometimes instead called a healthcare–associated infection. Such an infection can be acquired in hospital, nursing home, rehabilitation facility, outpatient clinic, diagnostic laboratory or other clinical settings. 

Main Roots of Transmission

I) Contact Transmission: The most important and frequent mode of transmission of nosocomial infections is by direct contact.

II) Droplet transmission: Transmission occurs when droplets containing microbes from the infected person are propelled a short distance through the air and deposited on the patient's body; droplets are generated from the source person mainly by coughing, sneezing, and talking, and during the performance of certain procedures, such as bronchoscopy.

III) Airborne transmission: Dissemination can be either airborne droplet nuclei (small-particle residue {5 µm or smaller in size} of evaporated droplets containing microorganisms that remain suspended in the air for long periods of time) or dust particles containing the infectious agent. Microorganisms carried in this manner can be dispersed widely by air currents and may become inhaled by a susceptible host within the same room or over a longer distance from the source patient, depending on environmental factors; therefore, special air-handling and ventilation are required to prevent airborne transmission. Microorganisms transmitted by airborne transmission include Legionella, Mycobacterium tuberculosis and the rubeola and varicella viruses.

IV) Common vehicle transmission: This applies to microorganisms transmitted to the host by contaminated items, such as food, water, medications, devices, and equipment.

V) Vector borne transmission: This occurs when vectors such as mosquitoes, flies, rats, and other vermin transmit microorganisms.