Comparative analysis of the clinical characteristic and lung microbiota in adult and elderly patients with pulmonary tuberculosis

Abstract

The proportion of elderly people infected with tuberculosis (TB) is increasing, and misdiagnosis and missed diagnosis are common. This study aimed to explore the diagnostic value of metagenomic next-generation sequencing (mNGS) for pulmonary TB (PTB) and to investigate age-related differences in lung microbial composition, clinical characteristics and imaging findings among PTB patients. We retrospectively recruited 162 suspected PTB patients, and finally 143 patients were used in this analysis. Patients were classified into two groups: adult (18 ≤ age < 60, n = 66) and elderly (Age ≥ 60, n = 77). Differences and associations in clinical characteristics, imaging findings, and lung microbiota were analyzed. Compared to adult patients, elderly patients had a higher prevalence of hypertension (31.17% vs. 9.09%, P = 0.0012), fever (20.78% vs. 4.55%, P = 0.0044) and chest tightness (24.68% vs. 10.61%, P = 0.0297), but a lower prevalence of chest pain (7.58% vs. 0%, P = 0.0139). For TB identification, mNGS had the highest positive rate (100%), followed by T-spot (74.75%), GeneXpert (37.80%) and acid-fast staining (AFS) (7.30%), and all the conventional methods showed slight higher positive rates in the elderly group compared to the adult group (P > 0.05). Bilateral lung infection was more common in elderly patients (79.22% vs. 60.61%, P = 0.0148), with infiltration (32.17%, 46/143), shadows (26.57%, 38/143), nodules (20.28%, 29/143), and bronchiectasis (20.28%, 29/143) being the most common imaging features. The diversity of the lung microbial communities was significantly lower in elderly patients compared to adults (P < 0.05). Clinical characteristics, imaging findings, and the top 20 most abundant species in lung microbiota showed significantly positive correlation. This study demonstrates that mNGS has excellent diagnostic value for PTB in both adult and elderly patients. Significant differences in clinical characteristics, imaging, and lung microbial composition were observed between the two groups. Understanding these differences may aid in the diagnosis and treatment of tuberculosis in elderly patients.