Legionella pneumophila in Bronchoalveolar Lavage Samples of Patients Suffering from Severe Respiratory Infections: Role of Age, Sex and History of Smoking in the Prevalence of Bacterium

Abstract

Introduction Legionella pneumophila is the most commonly detected cause of legionellosis, which is an acute respiratory tract infection with high morbidity and mortality rates.

Objective The aim of this study was to investigate the prevalence rate of L. pneumophila in bronchoalveolar lavages and study the role of sex, age and history of smoking as risk factors for susceptibility to the bacterium.

Methods One hundred bronchoalveolar lavage samples were collected from the Iranian health centers and immediately transferred to laboratory. The samples were cultured and those that were L. pneumophila positive were subjected to PCR method with respect to the 16S rRNA gene.

Results Twelve out of 100 samples were positive for L. pneumophila (12%). Patients older than 70 years had the highest incidence of L. pneumophila (17.77%). Prevalence of L. pneumophila in male and female patients was 14.81% and 8.69%, respectively. Total incidence of L. pneumophila in patients with and without history of smoking was 18% and 6%, respectively. There were significant differences in the incidence of bacterium between groups of our study.

Conclusion Sex, age and history of smoking are predominant risk factors for the occurrence of L. pneumophila. However, more studies should be undertaken to confirm these results.

Keywords: Legionella pneumophila; prevalence; bronchoalveolar lavages; respiratory infections; risk factors