[en] The study on microbial populations is a suitable tool to understand and apply control methods to improve the sanitary level of production in fish breeding and rearing centers, ensure health of sturgeon fingerlings at the time of their release into the rivers and also in the conversation and restoration of these valuable stocks in the Caspian Sea, Iran. A laboratory research based on Austin methods (Austin, B., Austin, D.A. 1993) was conducted for bacterial study on 3 sturgeon species naming A. persicus, A. stellatus and A. nudiventris during different growth stages. Bacterial flora of Acinetobacter, Moraxella, Aeromonas, Vibrio, Edwardsiella, Staphylococcus, Proteus, Yersinia, Pseudomonas and Plesiomonas were determined. The factors which may induce changes in bacterial populations during different stages of fife are the followings: quality of water in rearing ponds, different conditions for growth stages, suitable time for colonization of bacterial flora in rearing pond, water temperature increase in fingerlings size and feeding condition. (author)

[en] Nosocomial infections are known as infections which are acquired during patients hospitalization in hospitals. It has long history and causes to increase both therapy costs and problems of patient treatments. This study is for comparison of air microbial pollution in hospitals of towns (A) and (B) in Iran. This study is a descriptive-analytic type. Blood Agar culture was used for determining of microbial pollution. Statistic tests (central and scattering criterions) have been used for data analysis. Findings show that the most epidemical pathogen in view of air pollution in different parts of hospitals is non-urease Staphylococcus. It seems that because of using UV radiation, proper air ventilation and many facilities, air pollution in town (B) hospitals is less than town (A). (author)