THE MICROBIOME OF SPUTUM SAMPLES FROM LEGIONELOSIS ASSOCIATED PATIENTS VERSUS OTHER PNEUMONIA PATIENTS

Hila Mizrahi ^1,2 Yana Aizenberg-Gershtein ¹ Sarah Rodríguez-Martínez ¹ Yehonatan Sharaby ¹ Ingrid Brettar ³ Manfred Hofle ³ Malka Halpern ¹ Avi Peretz ²

¹Department of Biology and Environment, Oranim, University of Haifa, Kiryat Tivon, Israel
²Microbiology Lab, Baruch Padeh Medical Center, Poriya, Bar-Ilan University, Ramat-Gan, Israel
³Department of Vaccinology and Applied Microbiology, Helmholtz Centre for Infection Research (HZI), Braunschweig, Germany

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 this study was to analyze the bacterial community in sputum samples of hospitalized patients with pneumonia that were positive to Legionella presence by PCR (LGP) and to compare it to the bacterial community in sputum samples of pneumonia patients that were negative to Legionella presence by PCR (LGN). To achieve this goal DNA extracted from 133 sputum samples and amplified using primers targeting the V4 variable region of the bacterial 16S rRNA gene and sequenced by Illumina MiSeq platform.

The bacterial communities composition (%) in LGN PCR sputum samples was higher compared the bacterial communities composition (%) in LGP PCR sputum samples. In both LGN PCR sputum samples and LGP PCR sputum samples OTUs’ of two bacterial phyla; Proteobacteria and Firmicutes, were most abundant. Venn diagram for distribution by groups (LGP, LGN) and by age (40-60, 60-80, >80) showed that every group was characterized by different OTUs. Interestingly, in the LGP sputum samples Legionella was not the dominant genera, furthermore, Legionella abundance was relatively low compared to majority of species.

Our results show that LGP is characterized with different bacteria compared to LGN. It is important to use next generation sequencing technique in parallel to culture for receiving accurate bacterial composition identification of the sputum microbiome.