Most species belonging to Aeromonas genus, particularly those associated with human infections, are widely distributed in the environment, especially in freshwater, sewage, marine environments, and drinking water, and are also found in a wide range of animal and plant food products. The US Environmental Protection Agency proposed Aeromonas hydrophila as one of the contaminants of concern in waterborne diseases. Legionella pneumophila, the causative organism of Legionnaires disease, can infect and kill specific species of amoebae in aquatic environments and can multiply as an intracellular parasite in human phagocytic cells .Legionella spp. are commonly found in aquatic environments, and responsible for 1 to 5% of cases of community-acquired pneumonia (CAP). Approximately 70 to 90% of Legionella infections are caused by L. pneumophila serogroups 1 and 6. Scientists have realized that in the natural world, more than 99% of all bacteria exist as biofilms. PrimeOA Publications International is one of the leading Open Access Publishers which is publishing 700+ peer-reviewed journals. Journal of Bacteriology & Parasitology is one of the top journals which publish quality articles, findings dealing with Bacteria and Parasites of Medical relevance to human or veterinary health.