Nosocomial infection (NI) is an infection acquired whilst staying, visiting or working in a hospital or healthcare facility. ? It is also defined as an infection acquired in hospital by a patient who was admitted for a reason other than that infection or an infection occurring in a patient in a hospital or other health care facility in whom the infection was not present or incubating at the time of admission. ? One of the risk factors for such infection is bacterial contamination of hospital wards indoor air by bacteria. In view of that, the microbiological quality of air can be considered as a mirror of the hygienic condition for hospital wards.