Humans ; Bronchiolitis Obliterans/etiology* ; Early Diagnosis ; Pneumonia, Mycoplasma/complications* ; Consensus ; Child ; Mycoplasma pneumoniae ; China/epidemiology* ; Mass Screening ; Adenoviridae Infections/complications*

OBJECTIVES: To investigate the risk factors for plastic bronchitis (PB) in children with macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMPP) and to establish a nomogram prediction model. METHODS: A retrospective analysis was conducted on 178 children with MUMPP who underwent bronchoscopy from January to December 2023. According to the presence or absence of PB, the children were divided into a PB group (49 children) and a non-PB group (129 children). The predictive factors for the development of PB in children with MUMPP were analyzed, and a nomogram prediction model was established. The model was assessed in terms of discriminatory ability, accuracy, and clinical effectiveness. RESULTS: The multivariate logistic regression analysis showed that older age and higher levels of lactate dehydrogenase and fibrinogen were closely associated with the development of PB in children with MUMPP (P<0.05). A nomogram model established based on these factors had an area under the receiver operating characteristic curve of 0.733 (95%CI: 0.651-0.816, P<0.001) and showed a good discriminatory ability. The Hosmer-Lemeshow goodness-of-fit test indicated that the predictive model had a good degree of fit (P>0.05), and the decision curve analysis showed that the model had a good clinical application value. CONCLUSIONS The risk nomogram model established based on age and lactate dehydrogenase and fibrinogen levels has good discriminatory ability, accuracy, and predictive efficacy for predicting the development of PB in children with MUMPP.
Retrospective Studies ; Risk Factors ; Nomograms ; Mycoplasma pneumoniae/isolation & purification* ; Pneumonia, Mycoplasma/microbiology* ; Bronchitis/microbiology* ; Macrolides/therapeutic use* ; Drug Resistance, Bacterial ; Bronchoscopy ; Area Under Curve ; ROC Curve ; Fibrinogen/analysis* ; Age Factors ; Humans ; Male ; Female ; Infant ; Child, Preschool ; Child ; Adolescent ; L-Lactate Dehydrogenase/blood*

OBJECTIVES: To study the risk factors for hypoxemia in children with severe Mycoplasma pneumoniae pneumonia (SMPP). METHODS: A retrospective collection of clinical data from children diagnosed with SMPP at the Third Affiliated Hospital of Zhengzhou University from June to December 2023 was conducted. The patients were categorized into hypoxemia and non-hypoxemia groups. Logistic regression analysis was used to assess the risk factors for hypoxemia, and receiver operating characteristic (ROC) curve analysis was employed to analyze the diagnostic performance of various indicators. RESULTS: A total of 113 children with SMPP were included. Univariate logistic regression analysis showed that ferritin, aspartate aminotransferase, creatinine, creatine kinase isoenzyme, lactate dehydrogenase, alpha-hydroxybutyrate dehydrogenase, immunoglobulin G, complement C3, complement C4, age, extrapulmonary complications, and a chest computed tomography (CT) scan showing a bronchiolitis pattern were significant factors for hypoxemia in children with SMPP (P<0.05). Multivariate logistic regression analysis revealed that elevated ferritin levels, presence of extrapulmonary complications, and a bronchiolitis pattern on lung CT were independent risk factors for hypoxemia in these patients (P<0.05). The ROC curve analysis indicated that the combination of these three indicators for predicting hypoxemia had a sensitivity of 71.9%, a specificity of 95.1%, and an area under the curve of 0.888 (95%CI: 0.809-0.968). CONCLUSIONS In children with SMPP, when there are elevated ferritin levels, a bronchiolitis pattern on chest CT, and the presence of extrapulmonary complications, there should be a high level of vigilance for the potential development of hypoxemia.
Humans ; Pneumonia, Mycoplasma/complications* ; Male ; Female ; Risk Factors ; Child, Preschool ; Hypoxia/etiology* ; Retrospective Studies ; Child ; Logistic Models ; Infant ; ROC Curve ; Adolescent

OBJECTIVES: To study the characteristics of bronchoalveolar lavage fluid (BALF) microbial distribution at different stages of refractory Mycoplasma pneumoniae pneumonia (RMPP) in children and its relationship with immune function. METHODS: A total of 108 children with RMPP were enrolled. The relative abundance, richness, and diversity of BALF microbiota, as well as immune function, were compared between the acute phase (n=61) and recovery phase (n=47). The correlations between the richness and diversity of BALF microbiota and immune function were analyzed. RESULTS: The relative abundance of Propionibacterium, as well as the Simpson index, Shannon index, Chao1 index, and Observed species index of BALF microbiota in the acute phase were significantly lower than those in the recovery phase (P<0.05). The relative abundances of Streptococcus and Prevotella, as well as the levels of complement C3, complement C4, immunoglobulin A (IgA), immunoglobulin G (IgG), and immunoglobulin M (IgM), were significantly higher in the acute phase than in the recovery phase (P<0.05). Simpson, Shannon, Chao1, and Observed species indices were negatively correlated with levels of complement C3, complement C4, IgA, IgM, and IgG (P<0.05). CONCLUSIONS In children with RMPP, the relative abundance of Propionibacterium and the richness and diversity of BALF microbiota in the acute phase are lower than those in the recovery phase, while the relative abundances of Streptococcus and Prevotella are higher in the acute phase. Microbial richness and diversity are closely related to immune function.
Humans ; Male ; Pneumonia, Mycoplasma/microbiology* ; Female ; Bronchoalveolar Lavage Fluid/microbiology* ; Child, Preschool ; Child ; Infant ; Microbiota

OBJECTIVES: To investigate the predictive factors for plastic bronchitis (PB) in children with Mycoplasma pneumoniae pneumonia (MPP) and to establish a nomogram prediction model for PB occurrence. METHODS: A retrospective analysis was conducted on children with MPP hospitalized at The Affiliated Hospital of Xuzhou Medical University from January 2023 to June 2024. The patients were randomly divided into a training set (n=562) and a validation set (n=240) at a ratio of 7:3 using simple random sampling. In the training set, patients were categorized into a PB group (n=70) and a non-PB group (n=492) based on the occurrence of PB. Spearman correlation analysis was performed to exclude collinearity among variables, followed by univariate analysis and LASSO regression to identify predictive factors. A nomogram prediction model for PB in children with MPP was constructed. The discriminative ability of the model was assessed using receiver operating characteristic (ROC) curve analysis, model calibration was evaluated with calibration curves, and clinical utility was appraised through decision curve analysis. RESULTS: Compared with the non-PB group, the PB group exhibited significantly longer disease duration prior to bronchoscopy, prolonged fever duration, higher fever peaks, higher proportions of patients with a family history of allergy and personal allergy history, and a higher proportion of patients with pleural effusion, as well as significantly elevated levels of white blood cell count, neutrophil percentage, C-reactive protein, procalcitonin, fibrinogen, D-dimer, aspartate aminotransferase, alanine aminotransferase, creatine kinase, lactate dehydrogenase, immunoglobulin A, and interleukin-6, along with a significantly lower lymphocyte percentage (all P<0.05). LASSO regression analysis identified pleural effusion, procalcitonin, D-dimer, and lactate dehydrogenase as major predictive factors for PB occurrence in children with MPP. The nomogram model based on these factors demonstrated good discriminative ability (area under the ROC curve: 0.852 in the training set and 0.830 in the validation set), with satisfactory calibration and clinical benefit. CONCLUSIONS The nomogram prediction model based on pleural effusion, procalcitonin, D-dimer, and lactate dehydrogenase provides effective predictive performance for the occurrence of PB in children with MPP.
Humans ; Pneumonia, Mycoplasma/complications* ; Nomograms ; Male ; Female ; Child ; Child, Preschool ; Retrospective Studies ; Bronchitis/etiology* ; Infant ; ROC Curve ; Adolescent

OBJECTIVES: To identify risk factors for recurrent plastic bronchitis (PB) among children with Mycoplasma pneumoniae pneumonia (MPP). METHODS: The clinical data of children with MPP complicated by PB who underwent bronchoscopy at Gansu Province Maternity and Child Health Hospital between July 2023 and January 2025 were retrospectively analyzed. Patients were grouped into a single-episode PB group and a recurrent PB group according to the number of PB episodes. Multivariable logistic regression was used to identify risk factors for recurrent PB. Receiver operating characteristic (ROC) curve analysis was used to assess the diagnostic performance of individual and combined predictors. RESULTS: A total of 264 children were included; 188 (71.2%) had a single episode of PB and 76 (28.8%) had recurrent PB. Multivariable logistic regression analysis showed that decreased serum albumin, atelectasis, and fever persisting beyond 72 hours after the initial bronchoscopy were significantly associated with recurrent PB (all P<0.05). The combination of these predictors yielded a sensitivity of 82.9%, specificity of 61.7%, and an area under the ROC curve of 0.777 (95%CI: 0.714-0.839), outperforming any single predictor (P<0.05). CONCLUSIONS In children with MPP complicated by PB, decreased serum albumin, the presence of atelectasis, and fever persisting beyond 72 hours after the initial bronchoscopy are associated with an increased risk of PB recurrence. In such cases, early repeat or multiple bronchoscopic interventions should be considered.
Humans ; Pneumonia, Mycoplasma/complications* ; Male ; Female ; Risk Factors ; Recurrence ; Child, Preschool ; Bronchitis/etiology* ; Child ; Retrospective Studies ; Logistic Models ; Infant ; ROC Curve ; Adolescent

Humans ; Pneumonia, Mycoplasma/drug therapy* ; Mycoplasma pneumoniae/isolation & purification* ; Child ; Anti-Bacterial Agents/therapeutic use* ; Evidence-Based Medicine ; China

OBJECTIVES: To investigate the efficacy and safety of prolonged azithromycin (PAZM) versus switching to doxycycline (SDXC) in the treatment of macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMPP) in children. METHODS: A total of 173 children with MUMPP who were hospitalized in Baoji Central Hospital, from January to December 2023 were selected as subjects. According to the choice of secondary antibiotic after 72 hours of initial macrolide therapy, they were divided into two groups: PAZM and SDXC. The efficacy and adverse drug reactions were compared between the two groups, and the risk factors for refractory Mycoplasma pneumoniae pneumonia (RMPP) were analyzed. RESULTS: Compared with the PAZM group, the SDXC group had significantly shorter time to defervescence and time to cough relief, a significantly lower proportion of patients using glucocorticoids, and a significantly higher proportion of patients with lung lesion absorption (P<0.05). No adverse reactions such as liver and kidney function impairment and tooth discoloration were observed in either group. RMPP occurred in 47 cases in the PAZM group. The univariate analysis showed that lactate dehydrogenase levels and age were risk factors for RMPP (P<0.05). CONCLUSIONS The efficacy of SDXC is superior to that of PAZM in children with MUMPP, and short-term use of doxycycline is relatively safe.
Humans ; Pneumonia, Mycoplasma/drug therapy* ; Doxycycline/administration & dosage* ; Female ; Male ; Azithromycin/administration & dosage* ; Child ; Child, Preschool ; Anti-Bacterial Agents/administration & dosage* ; Macrolides/administration & dosage* ; Adolescent ; Mycoplasma pneumoniae/drug effects*

OBJECTIVES: To investigate the protective effect of the probiotic bacterium Streptococcus salivarius K12 (K12) against Mycoplasma pneumoniae (Mp) infection in mice. METHODS: Forty male BALB/c mice were randomized into normal control group, K12 treatment group, Mp infection group, and K12 pretreatment prior to Mp infection group. The probiotic K12 was administered daily by gavage for 14 days before Mp infection induced by intranasal instillation of Mp. Three days after Mp infection, the mice were euthanized for analysis of bronchoalveolar lavage fluid (BALF) cell counts and serum levels of secretory immunoglobulin A (sIgA), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). RT-qPCR was performed to detect the P1 and community-acquired respiratory distress syndrome ( CARDS ) toxin of Mp in the lung tissues and the mRNA expressions of TNF-α, IL-6, chemokine 1 (CXCL1), matrix metalloproteinase 9 (MMP9), mucin 5ac (MUC5ac), collagen 3a1 (Col3a1), Toll-like receptor 2 (TLR2) and TLR4; the protein expressions of TLR2 and TLR4 in the lung tissue were detected using Western blotting. Pathological changes in the lung tissue and airway remodeling were examined with HE staining and AB/PAS staining. RESULTS: Compared with the Mp-infected mice with PBS treatment, the infected mice with K12 treatment showed significantly lowered mRNA levels of P1 and CARDS in the lung tissue and reduced white blood cell counts in the BALF (P<0.05). In spite of the absence of significant differences in serum levels of inflammatory factors between the two groups, the mRNA expressions of TNF‑α, IL-6, CXCL1, MMP9, MUC5ac and COL3A1 and the mRNA and protein levels of TLR2 and TLR4 in the lung tissues were significantly lower in K12-treated mice, in which AB/PAS staining showed obviously decreased mucus secretion. CONCLUSIONS K12 pretreatment can effectively reduce pulmonary inflammatory responses, improve airway remodeling and alleviate lung injury in Mp-infected mice.
Animals ; Mice ; Pneumonia, Mycoplasma/metabolism* ; Mice, Inbred BALB C ; Toll-Like Receptor 2/metabolism* ; Mycoplasma pneumoniae ; Male ; Tumor Necrosis Factor-alpha/metabolism* ; Interleukin-6/metabolism* ; Lung/microbiology* ; Toll-Like Receptor 4/metabolism* ; Streptococcus salivarius ; Probiotics/administration & dosage* ; Bronchoalveolar Lavage Fluid ; Matrix Metalloproteinase 9/metabolism* ; Mucin 5AC/metabolism* ; Chemokine CXCL1/metabolism* ; Immunoglobulin A, Secretory/metabolism* ; Bacterial Toxins ; Bacterial Proteins

Mycoplasma hyopneumoniae is the pathogen causing swine mycoplasmal pneumonia. The lack of well-established animal models of M. hyopneumoniae infection has delayed the progress of M. hyopneumoniae-related anti-infection immunity studies. This paper reviews the inflammatory response, the recognition of M. hyopneumoniae by the innate immune system, and the role of innate immune cells, complement system, antimicrobial peptides, autophagy, and apoptosis in M. hyopneumoniae infection. The aim was to elucidate the important roles played by the components of the innate immune system in the control of M. hyopneumoniae infection, and prospect key research directions of innate immune response of M. hyopneumoniae infection in the future.
Animals ; Swine ; Mycoplasma hyopneumoniae ; Pneumonia of Swine, Mycoplasmal ; Immunity, Innate