Isolation of Legionella Pneumophila from Air of Water Coolers in Baghdad

Abstract

The bacterium Legionella is ubiquitous genus, belongs to the family Legionellaceae, comprising 52 species. The most common species is Pneaumophila, causing a febrile and pneumonic illness, found primarily in aquatic habitat and thrive at warm temperature. It is capable of surviving extreme ranges of environment, surviving up to 14 months in water. Legionella is water bacterium isolated from air conditioning systems, cooling waters and humidifiers in offices and hospitals. It gets to human mostly through blowing air from air of water cooling systems or aspiration of contaminated drinking water fumes. Infection may have fatality rate of up to 50%. They have been isolated from waters and ducts of aircoolers in various location in Baghdad. Sample were placed in test tubes containing nutrient broth with 50% yeast extract and taken immediately to a diagnostic laboratory at Al-Nisour University College in Baghdad city. Subcultures from each tube were taken to inoculate each of nutrient agar plate with 5% yeast extract, blood agar plates, EMB plates, S-S agar plates gram staining was made. All plates were placed in a desiccator with a beaker of water and incubated at 35°C except BA for 3 days. Colonies were described and sub cultured for purity, then gram stained and reported modified gram stain was applied for Legionella cells, Legionella was diagnosed in 27 samples out of 114 (23.7%). Bacterial genera repeatedly isolated and diagnosed were: Streptococcus, Staphylococcus, Escherichia, Pseudomonas, Klebsiella, Legionella, Agrobacter and Bacillus. The frequent isolate was Escherichia coli. Shelf life of Legionella in water was determined to control it by heat a temperature of 80°C destroyed the cells in 1 h. The heat tolerance of the cells was found to be 70°C but not 75°C. Persistence of Legionella in river water last up to 3 months. Cells were counted by the method of dilution to extinction. Legionella cell isolated have high resistance to antimicrobial agents, except to Amikacin, Nalidixic acid and Nitrofurantoin.