WHO defines HAI as "An infection which the affected patient acquired as a result of health care treatment for a reason other than the infection" 

Intensive care, emergency surgical and orthopedic procedures generate the most HAIs, according to studies by WHO and others

Patients with increased susceptibility to infection due to older age, underlying disease or cancer therapy are at higher risk of HAIs 

Most infections detected after 48 hours of hospitalization are considered to be HAIs. Infections that occur after the patient has left the hospital can be considered as HAIs if the infecting organisms were obtained during the hospital stay  

Urinary tract infections, post-operative infections and respiratory tract infections are the three most common types of HAIs (Ref. Magill SS; et. al, N Engl J Med. 2014; 370(13):1198-208)