Isolation, identification, characterization and antibiotic sensitivity profile of pathogenic Legionella pneumophilaisolates from different water sources

Abstract

To investigate the prevalence, isolation, identification, characterization, antibiotic profile and pathogenicity of Legionellaeisolated from various set of waters. Methods:A total of 400 water samples were collected from different water sources. Water samples were pretreated using acid treatment followed by concentration and culture on buffered charcoal yeast extract agar. Parameters like ability of Legionellaisolates to grow in various pH range, effect of different concentrations of chlorine and effect of different temperature optima were set up. Biochemical tests were performed to separate Legionellaeinto species. Antibiotic sensitivity tests and test for pathogenicity were also conducted on isolated strains. Results:The rates of isolation ofLegionella pneumophila(L. pneumophila) in different water sources were found to be 20% (lakes), 10% (ponds), 8% (water-tanks) and 1% (rivers). Most of the isolates could grow in variable pH 6–8 and it could also survive the normal level of chlorination and even at temperature of 42 C. Isolated species of Legionellaeresulted in identification of 5 different species,L. pneumophilabeing the dominant one. Strains ofL. pneumophilawere resistant to many antibiotics. Inoculation ofLegionellaeinto intracerebral route of suckling mice revealed thatL. pneumophilawas the most virulent. Conclusions:Serious and fatalL. pneumophilainfections may be transmitted through water.Legionella can survive under various conditions in various water sources. L. pneumophilais the important pathogen causing human disease. Great challen