Publish Time: 2023-10-18 Origin: 迪飞医学
Introduction
Mycoplasma pneumoniae（Mycoplasma pneumoniae, MP) is one of the common pathogens of pulmonary infection in children, and humans are the only host.Mycoplasma pneumonia（Mycoplasma pneumoniae pneumonia, MPP)Community-acquired pneumonia common in school-age children(community acquired pneumonia, CAP), accounting for 10%-40% of CAP in hospitalized children.In the early stage, due to macrolide resistance and a series of complex mechanisms, refractory Mycoplasma pneumoniae pneumonia (refractory mycoplasma pneumoniae pneumonia, RMPP) is increasing, often leading to poor prognosis and sequelae such as atelectasis, pulmonary necrosis, bronchiectasis, and bronchiolitis obliterans.Some studies have found that the microbiota changes significantly during lower respiratory tract (LRT) infection, which is closely related to the prognosis or course of pneumonia.
In this study, bronchoalveolar lavage fluid from children diagnosed with RMPP or non-refractory Mycoplasma pneumoniae pneumonia (NRMPP) was examined for mNGS etiology and the relationship between the lower respiratory tract microbiota and RMPP was analyzed., relevant research results were published in Translational Pediatrics.
Research result
The study included 52 children, including 9 males and 18 females in the NRMPP group and 11 males and 14 females in the RMPP group.Diffei Medical also provided comparative metagenomic analysis for the enrolled patients. Through the analysis, it was found that:
alpha diversity
The Shannon index (richness) of the RMPP group was much lower than that of the NRMPP group, while the Simpson index (evenness) was higher. The diversity of the RMPP group was significantly lower than that of the NRMPP group.
beta diversity
There was a significant difference in diversity between groups based on Bray-Curtis distance (P<0.001).
Figure 1 From left to right are α diversity-Shannon index, α diversity-Simpson index, β diversity-Bray-Curtis distance between groups.
Highly abundant differential species between groups
The relative abundance of Mycoplasma genera in the NRMPP group was significantly lower than that in the RMPP group, and the commensal microorganisms Streptococcus, Neisseria, Veillonella, Rosette and Prevotella, as well as the opportunistic pathogenic microorganisms Acinetobacter, The abundance of Pseudomonas and Ralstonia was significantly increased in the NRMPP group.Almost all RMPP groups had significantly higher M. pneumoniae loads than the NRMPP group, indicating that MP occupied all niches of LRT.It was found that high abundance of human adenovirus type 7 or human bocavirus type I was detected in the samples of 4 children in the RMPP group with significantly reduced MP abundance.
Figure 2 Species with high abundance differences between groups (genus level)
Biomarkers for RMPP and NRMPP groups
LEfSe was used to explore the taxa that had the greatest impact on the different microbial conditions between groups, and it was found that Mycoplasma and Neisseria had the greatest impact on the RMPP group, among which Mycoplasma pneumoniae and Neisseria luteum were the most abundant.
Differences in gene function distribution between RMPP and NRMPP groups
Resistance genes (ARGs) were successfully annotated in the genomes of Mycoplasma pneumoniae in 14/25 cases of the RMPP group and 18/27 cases of the NRMPP group, and the NRMPP group had more ARGs annotations.Compared with the NRMPP group, the RMPP group had fewer annotations of virulence factor genes (VFGs), but the relative abundance of adhesion-related virulence genes was higher.Metabolic pathway LEfSe analysis found that functions related to terpene and polyketide metabolism, lipid metabolism, DNA replication or repair, and carbohydrate metabolism were enriched in the RMPP group.
Figure 3 Heat map of relative abundance of ARGs and VFGs on the MP genome between groups
/ in conclusion /
The LRT microbiota of children in the RMPP group was much simpler than that in the NRMPP group, and most were dominated by MP.Once MPs occupy all ecological niches, a large number of adherent airway epithelial cells will necrosis and fall off, inflammatory cells will infiltrate, secrete pro-inflammatory cytokines, and the release of CARDS toxins will cause severe tissue damage to the patient. This overactivated immune system may be The main causes of RMPP. Diffei mNGS provides strong support for precise treatment plans with its rapid, sensitive and accurate pathogen identification capabilities.
references:
Chen J, Xi Z, Shi Y, Liu L, Wang L, Qian L, Lu A. Highly homogeneous microbial communities dominated by Mycoplasma pneumoniae instead of increased resistance to macrolide antibiotics is the characteristic of lower respiratory tract microbiome of children with refractory Mycoplasma pneumoniae pneumonia. Transl Pediatr 2021;10(3):604-615. doi: 10.21037/tp-20-404
Author: Shan Na Review: Chao Hua Xi Shi Typesetting: Ah Xin