Legionella is an aquatic Gram-negative, rod shaped, facultative aerobic bacterium. Eighteen Legionella species utilize a similar mechanism to infect human phagocytic cells resulting in pneumonia. The aim of the current study was to compare the physiology of environmental and clinical Legionella isolates. To achieve this goal, we performed a hemolysis assay using sheep red blood cells and we followed Legionella growth curves in three different temperatures: 30°C, 37°C, 42°C.
Significant differences were found between clinical and environmental strains. The clinical strains caused much more hemolysis than the environmental strains. Environmental strains grew better at 30°C and the clinical isolates grew better and faster at 42°C. The results demonstrate that clinical and environmental strains have different physiological traits.
