title: Oral metagenome of homo sapiens
design: A total of 65 pediatric participants were enrolled, comprising two groups. Group A included 32 children under 18 years diagnosed with severe or very severe pneumonia according to the WHO pre-2013 criteria. Exclusion criteria were hospitalization within the previous 14 days, resolution of lower chest wall indrawing following bronchodilator therapy, prior antibiotic use, or immunocompromised status such as HIV infection, cancer. Group B included 33 healthy children under 18 years, either siblings of the cases or, if unavailable, children from neighboring families, with no recent illness or antibiotic use within the preceding week. Relevant demographic and clinical dataincluding age, gender, and clinical presentationwere systematically recorded for all participants.