Late Breaking Abstract - Dysbiosis in the lung microbiome of patients with HIV and pneumonia is associated with worse disease severity and mortality scores

<b>Background:</b> The lung microbiome is an explosive area of research, but little is known about the clinical significance of dysbiosis in this microbiome in patients with pneumonia. This study correlated dysbiosis in the lung microbiome of patients with HIV and pneumonia, with clinical severity and mortality scores. <b>Methods:</b> Sputum was collected from HIV-positive patients presenting with pneumonia. A control group of sputum samples was obtained from patients with HIV but no evidence of pneumonia. 16S rRNA sequencing was performed to determine the microbial composition of the respective lung microbiomes. Pneumonia severity was defined by both the CURB-65 and ACHU scores. <b>Results:</b> A loss of microbial diversity could be illustrated in the group with pneumonia, when compared with a control group of HIV positive patients. There was a dominance of <i>Proteobacteria</i> in those with pneumonia, while <i>Firmicutes</i> were most dominant in the control group. A loss of alpha diversity by Observed, Shannon and Inverse Simpson indices was found in patients with pneumonia. A loss of alpha diversity correlated significantly with worse clinical severity scores, using both the CURB-65 (fig 1) and ACHU (fig 2) indices. <b>Conclusion:</b> The degree of dysbiosis in the lung microbiome of patients with HIV and pneumonia correlated with clinical severity and mortality prediction scores. Dysbiosis in the lung microbiome was associated with more severe disease, but whether the microbiota-host interactions are actively involved in disease progression, or whether this is a mere bystander phenomenon needs to be further investigated.