Assessment of biological agents in the air of different wards in Imam Khomayni and Shahid Zare hospitals in Sari, 2007

Poor environmental health management in hospitals is one of the most important causative factors for developing of infectious diseases in hospitals. Emission of air borne biological agents is one of the effective ways of infection transmission. This study was carried out to survey of biological air borne concentrations in the air of two hospitals in Sari city. This cross sectional study was carried out during 6 month (from July to December 2007) in Emam Khomayni and Zare hospital wards once a week in the morning and in the afternoon using air sampling pump and filter. In total 98 samples were collected from the air and samples were cultured based on the standard methods. Then type of germs and the number of colonies and morphology of microorganisms were evaluated. This survey showed that all studied wards in both hospitals were polluted to different type of microorganism's air borne. Biological agent concentrations indoor all wards of Emam Khomayni hospital were higher than those measured in wards of Zare hospital. Staphylococcus, Pseudomonas, and gram positive bacteria were among the most prevalent microorganisms in the air of both hospitals respectively. Maximum biological agent pollution was observed at general surgery ward in Emam Khomayni hospital. This study showed that the number and type of microorganisms in the air of Emam Khomayni hospital wards were higher than those measured in Zare hospital wards. The high number of the persons in the ward was the key factor influencing the level of biological air borne in the air of Emam Khomayni hospital. Other related factors such as high numbers of visitors, lowefficiency and old ventilation system and also low maintenance of air conditioning system may influence the biological air borne concentrations in studied hospitals.