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 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 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

Objective: To describe the clinical characteristics of Mycoplasma pneumoniae infection and analyze the factors associated with co-infections with other pathogens in children, and provide evidence for improvement of community acquired pneumonia (CAP) prevention and control in children. Methods: Based on the surveillance of hospitalized acute respiratory infections cases conducted in Soochow University Affiliated Children's Hospital (SCH), the CAP cases aged <16 years hospitalized in SCH between 2018 and 2021 were screened. The pathogenic test results of the cases were obtained through the laboratory information system, and their basic information, underlying conditions, and clinical characteristics were collected using a standardized questionnaire. The differences in clinical characteristics between M. pneumoniae infection and bacterial or viral infection and the effect of the co-infection of M. pneumoniae with other pathogens on clinical severity in the cases were analyzed; logistic regression was used to analyze the factors associated with the co-infections with other pathogens. Results: A total of 8 274 hospitalized CAP cases met the inclusion criteria. Among them, 2 184 were positive for M. pneumoniae (26.4%). The M. pneumoniae positivity rate increased with age (P<0.001), and it was higher in girls (P<0.001) and in summer and autumn (P<0.001). There were statistically significant differences in the incidence of wheezing, shortness of breath, wheezing sounds and visible lamellar faint shadow on chest radiographs, as well as fever and hospitalization days among M. pneumoniae, bacterial, and viral infection cases (all P<0.05). In the cases aged <60 months years, co-infection cases had higher rates of wheezing, gurgling with sputum and stridor; and in the cases aged ≥60 months, co-infection cases had a higher rate of shortness of breath (all P<0.05). Multifactorial logistic regression analysis showed that being boys (aOR=1.38,95%CI:1.15-1.67), being aged <6 months (aOR=3.30,95%CI:2.25-4.89), 6-23 months (aOR=3.44,95%CI:2.63-4.51), 24-47 months (aOR=2.50,95%CI:1.90-3.30) and 48-71 months (aOR=1.77,95%CI:1.32-2.37), and history of respiratory infection within 3 months (aOR=1.28,95%CI:1.06-1.55) were factors associated with co-infections of M. pneumoniae with other pathogens. Conclusions: M. pneumoniae was the leading pathogen in children hospitalized due to CAP. M. pneumoniae infections could cause fever for longer days compared with bacterial or viral infections; M. pneumoniae was often co-detected with virus or bacteria. Being boys, being aged <72 months and history of respiratory infection within 3 months were associated factors for co-infections.
Bacteria ; Child ; Coinfection/epidemiology* ; Community-Acquired Infections/epidemiology* ; Dyspnea ; Female ; Humans ; Male ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma/microbiology* ; Respiratory Sounds ; Respiratory Tract Infections/epidemiology* ; Virus Diseases

OBJECTIVETo investigate the association of drug resistance of Mycoplasma pneumoniae (MP) with DNA load and genotypes in children with MP pneumonia.

METHODSA total of 230 children who were hospitalized and diagnosed with MP pneumonia between January 2012 and December 2016 were enrolled. Throat swabs were collected from the 230 children, and a rapid drug sensitivity assay was used to determine the sensitivity of clinical isolates of MP to nine commonly used antibacterial agents. Quantitative real-time PCR was used to measure MP-DNA load in throat swabs. PCR sequencing was used to determine the genotype of 2063 locus of the MP 23S rRNA V domain.

RESULTSOf the 230 children, 86 (37.4%) had genotype A in 2063 locus, 134 (58.3%) had genotype G, 8 (3.5%) had genotype C, and 2 (0.9%) had genotype T. Mutant strains (genotype G+C+T) had a significantly higher MP-DNA load than wild-type strains (genotype A) (P<0.05). The strains resistant to erythromycin, azithromycin, clarithromycin, and clindamycin had a significantly higher MP-DNA load than non-resistant strains (P<0.05). MP had a high drug resistance rate to macrolide antibiotics. More than 60% of the cases with resistance to macrolides were found to have A2063G mutations. MP was rarely resistant to quinolones (less than 2%).

CONCLUSIONSMutations in 2063 locus of the MP 23S rRNA V domain may result in the resistance of MP to macrolides and the change in DNA load and can be used as a basis for selecting drugs for MP.

Child ; Child, Preschool ; DNA, Bacterial ; analysis ; Drug Resistance, Bacterial ; Female ; Genotype ; Humans ; Infant ; Male ; Mycoplasma pneumoniae ; drug effects ; genetics ; Pneumonia, Mycoplasma ; drug therapy ; microbiology

OBJECTIVETo study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.

METHODSA total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.

RESULTSThe cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).

CONCLUSIONSMPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.

Antibodies, Bacterial ; blood ; Child ; Child, Preschool ; DNA, Bacterial ; analysis ; Early Diagnosis ; Female ; Humans ; Infant ; Male ; Pneumonia, Mycoplasma ; diagnosis ; microbiology

Humans ; Mycoplasma pneumoniae ; pathogenicity ; Pneumonia, Mycoplasma ; microbiology

Humans ; Mycoplasma pneumoniae ; Pneumonia, Mycoplasma ; microbiology

OBJECTIVETo compare the detection rates of Mycoplasma pneumoniae (MP) from nasopharyngeal aspirates (NPA) and bronchoalveolar lavage fluid (BALF) in children with pneumonia.

METHODSA total of 164 hospitalized children with pneumonia were enrolled. NPA and BALF of these children were collected within 24 hours of admission, and MP-DNA was detected by fluorescence quantitative PCR. Venous blood samples of all these children were collected within 24 hours of admission and on days 7-10 of treatment, and serum MP-IgM was detected using ELISA.

RESULTSThe positive rate of MP-DNA in NAP of the 164 cases was 51.8% , which was lower than 63.4% as the detection rate of MP-IgM in serum (P=0.044), and the two detection rates were moderately consistent with each other (Kappa=0.618, P<0.01). The positive rate of MP in BALF was 71.3%, which was not significantly different with that of MP-IgM in serum (P>0.05), and the detection rates were well consistent (Kappa=0.793, P<0.01). The detection rate of MP in NPA was lower than that in BALF (P<0.01), with moderate consistency between two of them (Kappa=0.529, P<0.01). The median MP copy number in BALF was significantly higher than that in NPA (P<0.01). The MP detection rates in NPA and BALF were significantly different among different courses of disease (P<0.05). As the course of disease extended, the MP detection rates in both NPA and BALF showed a declining trend; children with MP pneumonia of 1-2 weeks' duration and 2-4 weeks' duration had a higher MP-DNA detection rate in BALF than in NPA (P<0.05).

CONCLUSIONSMP-DNA in BALF has a high sensitivity, with a great significance for early diagnosis of MP pneumonia, while NPA MP-DNA tests may lead to a missed diagnosis.

Adolescent ; Bronchoalveolar Lavage Fluid ; microbiology ; Child ; Child, Preschool ; DNA, Bacterial ; analysis ; Female ; Humans ; Infant ; Male ; Nasopharynx ; microbiology ; Pneumonia, Mycoplasma ; diagnosis

No abstract available.
Acute Kidney Injury/microbiology ; Anti-Bacterial Agents/therapeutic use ; Biopsy ; Humans ; Kidney/*microbiology ; Male ; Middle Aged ; Mycoplasma pneumoniae/drug effects/*isolation & purification ; Nephritis/diagnosis/drug therapy/*microbiology ; Pneumonia, Mycoplasma/diagnosis/drug therapy/*microbiology ; Skin Diseases, Bacterial/diagnosis/drug therapy/*microbiology ; Steroids/therapeutic use ; Treatment Outcome ; Vasculitis/diagnosis/drug therapy/*microbiology