Besharat Rahimi1 and Ahmad Vesal2*

1Advanced Thoracic Research Centre, Tehran University of Medical Science, Tehran, Iran.
2Department of Pediatric Cardiology , Rajaie Cardiovascular Medical and Research Center,
Iran University of Medical sciences, Tehran, Iran.


Legionella pneumophila is one of the most severe causative agents responsible for lower respiratory tract infections. Pathogenesis of Legionella diseases is mainly occurred due to the activities of some latent virulence factors. The present investigation was carried out to study the prevalence rate of L. pneumophila and its putative virulence factors in the respiratory samples of patients. Three-hundred and fifty respiratory samples were taken from patients suffered from RTIs. All samples were cultured and their positive results were subjected to several PCR reaction.  Prevalence in patients suffered from RTIs were 11.53%. lidA (70.58%), ralF (23.52%) and ivhB (17.64%) were the most commonly detected virulence factors in the L. pneumophila recovered from the respiratory samples. Considerable presence of virulent strains of L. pneumophila in patients showed that important public health issue facing hospitalized patients.

Keywords: Legionella pneumophila, Respiratory tract infections, Prevalence, Virulence factors.