Abstract:

Objective To explore the difference of sputum flora in healthy population, latent tuberculosis infection (LTBI) and active pulmonary tuberculosis patients. Methods From November 2016 to December 2017, 53 healthy subjects from Shenzhen Center of Chronic Diseases Prevention and Control were enrolled as group A, 41 registered patients with confirmed LTBI were enrolled as group B, and 54 patients with newly treated active tuberculosis were enrolled as group C. The 148 sputum samples of the lower respiratory tract (cheese sputum and mucus sputum were preferred) were collected from all the subjects in the morning when limosis. Total DNA was extracted from sputum samples, and 16S rRNA V4-V5 region genes were sequenced by high-throughput sequencing, the sequencing results were analyzed by bioinformatics. Results Through high-throughput sequencing analysis of the 148 sputum samples, 14136502.0 effective sequences and 21712.00 operational taxonomic units (OTU) were obtained. Alpha diversity analysis showed that the Pielou_e index of group A was 0.85 (0.82, 0.88), which was significantly higher than that of group C (0.83 (0.78, 0.86), H=4.462, P=0.035). Beta diversity analysis showed that there were differences in sputum flora composition among the three groups (H=2.027, P=0.002). Species analysis of different bacterial groups showed significant differences in levels of different Phylum (Firmicutes, Fusobacteria, Spirochaetes), Class (Flavobacteriia, Fusobacteriia, Spirochaetes), Order (Flavobacteriales, Lactobacillales, Fusobacteriales, Burkholderiales, Spirochaetales), Family (Porphyromonadaceae, Flavobacteriaceae, Fusobacteriaceae, Leptotrichiaceae, Burkholderiaceae, Spirochaetaceae), Genus (Capnocytophaga, Porphyromonas, Fusobacterium, Leptotrichia, Treponema) and Species (Nanceiensis,Parvula) among the three groups. Of them, the richness of Burkholderiales (0.01 (0.00, 0.02)) and Burkholderiaceae (0.01 (0.00, 0.01)) in group C was significantly higher than those in group A (0.00 (0.00, 0.01) and 0.00 (0.00, 0.00), respectively) and group B (0.00 (0.00, 0.01) and 0.00 (0.00, 0.00), respectively) (group C vs. group A: H values were 9.733 and 4.799, P values were 0.002 and 0.028, respectively; group C vs. group B: H values were 12.134 and 8.152, respectively, P values were both <0.01). Conclusion Mycobacterium tuberculosis infection did not change the richness of human sputum bacteria, however, it caused differences in the composition of the bacterial community.

Key words: Mycobacterium tuberculosis, Sputum, Bacterial structures, Biodiversity, Comparative study