This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Sterilization and Disinfection, Subject name: Microbiology
Hand washing is most important method for prevetion of nosocomial infection because - 
Select and explain. 
A. It is most common mode of transmission, B. It can enhance Airborne infection, C. Hands can generate droplets, D. All of the above
A: It is most common mode of transmission
Answer: A: It is most common mode of transmission 
Explanation: Ans. is 'a' i.e., It is most common mode of transmissiono There are following types of modes of transmission of hospital-acquired infections.1) Contact transmission# It is the most common and most preventable means of transmission. It is divided into two types -i) Direct contact : It involves contact of body surface to body surface with a physical transfer of microorganisms. Hand contact is most common mode of transmission.ii) Indirect contact: It involves body surface contact with a contaminated intermediate object.o As hand contact is the most common mode of transmission, the best preventive measure of nosocomial infection is proper hand hygiene.2) Droplet transmission# It occurs when droplet containing microorganisms from an infected person are propelled through the air (e.g. coughing, sneezing) and land on the mouth, eyes or nose of another person.3) Airborne transmission# It results when a droplet containing microorganisms evaporates and remains suspended in air for a long time (this should not be confused with droplet infection, in which transmission is immediate and droplets do not remains suspended in the air).# Airborne transmission also occurs by dust particles containing microorganism.4) Vehicle transmission# It refers to transmission of infection by contaminated items such as food, water, medications, devices and equipment.