Assessment of airborne bacteria in open sewage associated environment

Waste water of municipal sewerage system contains several types’ of pathogenic bacteria which can become air borne in case of mechanical disturbance. There is some evidence which indicate that enteric diseases prevailed in communities that may be associated with aerosols generated from waste water containing enteric pathogens. The present aero-bacteriological investigation included enumeration, identification, numerical analysis, and seasonal variation of different types of cultivable airborne bacteria with inhalant fraction of gram-negative bacteria in sewage associated environment, in order to develop efficient strategies to reduce health risk for this environment. The aero-bacteriological sampling has been done fortnightly for a period of one year. Bio load recorded was 3280.79±3199.262, 41.96±32.386 and 3.13±2.007 of total viable bacteria, inhalant gram-negative bacteria and total enteric bacteria respectively. Noninhalant fractions of total viable types of bacteria and gram positive rods were recorded highest during the summer, whereas; during the winter gram negative bacteria were dominant constituent. The most frequently present airborne bacteria were identified as the species of the genera, Klebsiella, Proteus and Escherichia, among the family Enterobacteriaceae; other species of gram-negative bacteria, i.e. Acinetobacter, Pseudomonas and Salmonella were also reported from this environment. The inhalant fraction of viable bacteria, were recorded highest during the season with moderate to high humidity and moderate temperature, suggesting that transitional period of seasons would be harmful for the inhabitants of adjacent area.