Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: Screening of the anti-mycobacterial activity of throat swab-derived microbial culture supernatants from TB close contacts. (A) Effects of pooled throat swab-derived microbial culture supernatants on the in vitro growth of BCG. (B) Effects of culture supernatants derived from 12 individual participants on the in vitro growth of BCG. The red boxes highlight samples 5 and 11, which showed the most prominent inhibitory activity against BCG growth among all 12 individuals tested. (C) Representative colony images showing the inhibitory effects of culture supernatants from different individuals on BCG growth. (D-F) PMA-differentiated THP-1 macrophages were infected with BCG (D), H37Rv (E), or M. smegmatis (F), and treated with culture supernatants at the indicated concentrations; intracellular viable bacterial loads were then measured. For the H37Rv infection shown in (E), the 50% supernatant concentration was not tested owing to limited volume of the pooled supernatant. Results are expressed as the CFU index and presented as the mean ± standard deviation. *, P<0.05; **, P<0.01; ****, P<0.0001; ns, not significant. BCG, Bacillus Calmette-Guérin; CFU, colony-forming unit; TB, tuberculosis.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: Screening, Activity Assay, Derivative Assay, In Vitro, Infection, Concentration Assay, Standard Deviation

Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: Isolation, identification, and anti-mycobacterial activity validation of a functional S. oralis strain. (A) Effects of candidate functional strain culture supernatants on the in vitro growth of BCG. (B) Effects of culture supernatants from monoclonal isolates obtained from sample 11 on the in vitro growth of BCG; the red box indicates strain 11-9, which was selected for subsequent experiments. (C-E) Changes in viable intracellular H37Rv, BCG, and M. smegmatis burdens in THP-1-derived macrophages after treatment with the culture supernatant of strain 11-9. Results are expressed as the CFU index and presented as the mean ± standard deviation. *, P<0.05; **, P<0.01; ***, P<0.001; ****, P<0.0001. BCG, Bacillus Calmette-Guérin; CFU, colony-forming unit.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: Isolation, Activity Assay, Biomarker Discovery, Functional Assay, In Vitro, Derivative Assay, Standard Deviation

Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: Screening of the anti-mycobacterial activity of throat swab-derived microbial culture supernatants from TB close contacts. (A) Effects of pooled throat swab-derived microbial culture supernatants on the in vitro growth of BCG. (B) Effects of culture supernatants derived from 12 individual participants on the in vitro growth of BCG. The red boxes highlight samples 5 and 11, which showed the most prominent inhibitory activity against BCG growth among all 12 individuals tested. (C) Representative colony images showing the inhibitory effects of culture supernatants from different individuals on BCG growth. (D-F) PMA-differentiated THP-1 macrophages were infected with BCG (D), H37Rv (E), or M. smegmatis (F), and treated with culture supernatants at the indicated concentrations; intracellular viable bacterial loads were then measured. For the H37Rv infection shown in (E), the 50% supernatant concentration was not tested owing to limited volume of the pooled supernatant. Results are expressed as the CFU index and presented as the mean ± standard deviation. *, P<0.05; **, P<0.01; ****, P<0.0001; ns, not significant. BCG, Bacillus Calmette-Guérin; CFU, colony-forming unit; TB, tuberculosis.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: Screening, Activity Assay, Derivative Assay, In Vitro, Infection, Concentration Assay, Standard Deviation

Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: Isolation, identification, and anti-mycobacterial activity validation of a functional S. oralis strain. (A) Effects of candidate functional strain culture supernatants on the in vitro growth of BCG. (B) Effects of culture supernatants from monoclonal isolates obtained from sample 11 on the in vitro growth of BCG; the red box indicates strain 11-9, which was selected for subsequent experiments. (C-E) Changes in viable intracellular H37Rv, BCG, and M. smegmatis burdens in THP-1-derived macrophages after treatment with the culture supernatant of strain 11-9. Results are expressed as the CFU index and presented as the mean ± standard deviation. *, P<0.05; **, P<0.01; ***, P<0.001; ****, P<0.0001. BCG, Bacillus Calmette-Guérin; CFU, colony-forming unit.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: Isolation, Activity Assay, Biomarker Discovery, Functional Assay, In Vitro, Derivative Assay, Standard Deviation

Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: Preliminary physicochemical characterization of anti-mycobacterial active components in S. oralis culture supernatant. (A,B) Effects of ethanol precipitation fractions on the in vitro growth of BCG and M. smegmatis . (C,D) Effects of different ethanol-precipitated fractions on viable intracellular BCG and M. smegmatis burdens in THP-1-derived macrophages. (E) Effects of culture supernatant on in vitro BCG growth after proteinase K treatment or heat-inactivated proteinase K control treatment. (F) Effects of culture supernatant on viable intracellular BCG burden in THP-1-derived macrophages after proteinase K treatment or heat-inactivated proteinase K control treatment. Results are expressed as the CFU index and presented as the mean ± standard deviation; *, P<0.05; **, P<0.01; ***, P<0.001; ****, P<0.0001; ns, not significant. BCG, Bacillus Calmette-Guérin; CFU, colony-forming unit.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: Ethanol Precipitation, In Vitro, Derivative Assay, Control, Standard Deviation

Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: Effect of S. oralis culture supernatant on autophagy-related protein expression in macrophages. (A) Western blot analysis of mTOR, p62, LC3B-I/II, and GAPDH protein levels in THP-1-derived macrophages treated with different concentrations of the S. oralis culture supernatant under uninfected or BCG-infected conditions. (B-D) Densitometric quantification of the relative expression levels of mTOR, p62, and LC3B-II, respectively. GAPDH was used as the internal control. Data are presented as the mean ± standard deviation. *, P<0.05; **, P<0.01; ns, not significant. BCG, Bacillus Calmette-Guérin; GAPDH, glyceraldehyde-3-phosphate dehydrogenase.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: Expressing, Western Blot, Analysis, Derivative Assay, Infection, Control, Standard Deviation

Journal: Journal of Thoracic Disease

Article Title: Upper respiratory tract commensal Streptococcus oralis inhibits mycobacterial growth by producing bioactive molecules and inducing macrophage autophagy

doi: 10.21037/jtd-2026-2039

Figure Lengend Snippet: In vivo antibacterial activity of S. oralis culture supernatant in mouse surrogate mycobacterial infection models. (A) Schematic workflow of the acute M. smegmatis infection model. C57BL/6 mice received culture supernatant from strain 11-9 by oral gavage, were infected intravenously with M. smegmatis , and were assessed for lung bacterial burden at the experimental endpoint. (B) Viable M. smegmatis burdens in lung tissue from each group. (C) Schematic workflow of the systemic BCG infection model. Mice were intravenously infected with BCG, treated by oral gavage with culture supernatant from strain 11-9 beginning on day 3 after infection, and assessed for tissue bacterial burden at the experimental endpoint. (D,E) Viable BCG burdens in the lungs and spleens of mice in each group. Results are expressed as the CFU index and presented as the mean ± standard deviation. *, P<0.05; **, P<0.01. BCG, Bacillus Calmette-Guérin; CFU, colony-forming unit.

Article Snippet: The Mtb reference strain H37Rv (ATCC 27294), the attenuated Mycobacterium bovis Bacillus Calmette-Guérin (BCG) strain (ATCC 35733), and M. smegmatis (ATCC BAA-535) were maintained in our laboratory.

Techniques: In Vivo, Activity Assay, Infection, Tissue, Standard Deviation