Antibiotic-induced gut microbiota dysbiosis aggravates Mycoplasma pneumoniae infection

Objective To investigate the influences of antibiotic-induced gut microbiota dysbiosis on Mycoplasma pneumoniae (Mp) airway infection. Methods C57BL/6J mice were treated with vancomycin and gentamicin for 21 d by oral delivery and then intranasally infected with Mp. Quantitative real-time PCR (qPCR) was performed to detect five major phyla of gut microbiota in mouse fecal specimens before and after antibiotic treatment and the loads of Mp in lung tissues on 3 d and 7 d after infection. Pathological changes in lung tissues were evaluated with HE staining. IFN-γ and IL-4 secreted by spleen CD4+ T cells and CD8+ T cells were analyzed by flow cytometry. Mp-specific IgM and IgG in mouse serum samples were measured by indirect enzyme-linked immunosorbent assay (ELISA). Results Vancomycin and gentamicin treatment significantly reduced the number of Bacteroidetes in mouse feces, but increased the amount of Firmicutes. Meanwhile, the numbers of δ, γ-Proteobacteria, Actinomycetes and Tenericutes also changed. These antibiotic-induced gut microbiota alterations in mice with Mp infection increased the loads of Mp in lung tissues and the pathological scores of lung tissue inflammation on 3 d and 7 d after infection, and reduced the number of IFN-γ-secreting spleen CD4+ T lymphocytes on 7 d. Conclusions Antibiotic-induced gut microbiota dysbiosis aggravated Mp airway infection. Key words: Gut microbiota dysbiosis; Mycoplasma pneumoniae; Antibiotics; Inflammation