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

OBJECTIVE: To investigate the application value of bronchoalveolar lavage fluid (BALF) metagenomic next-generation sequencing (mNGS) in etiological diagnosis of children with hematological malignancies complicated with pneumonia. METHODS: We retrospectively analyzed the clinical data of children with hematological malignancies who underwent BALF mNGS pathogenic detection due to pneumonia. All patients underwent mNGS detection of bronchoalveolar lavage fluid as well as traditional methods(including sputum culture, bronchoalveolar lavage fluid culture, blood culture, serological detection of pathogens, etc.). By analyzing the results of mNGS and traditional methods, we compared key indicators such as the positive rate, etiological distribution. RESULTS: A total of 26 children with hematological malignancies enrolled in the study, including 12 males and 14 females, with a median age of 4.9 (1.8-14.9) years, underwent bronchoalveolar lavage (BAL) 35 times. A total of 17 pathogenic microorganisms were detected in BALF mNGS, including 9 cases of bacterial infection, 10 cases of viral infection, 3 cases of fungal infection, 2 cases of mycoplasma infection and 8 cases of mixed infection, and the most commonly detected bacteria, viruses and fungi were streptococcus pneumoniae, cytomegalovirus and pneumocystis jirovecii, respectively. The positive rate of mNGS detection (91.43%) was significantly higher than that of traditional methods detection (20%, P <0.001). A total of 25 cases were adjusted according to BALF mNGS results. CONCLUSION The application of BALF mNGS technology can improve the detection rate of the pathogens in children with hematological malignancies complicated with pneumonia, initially revealed the pathogen spectrum of pulmonary infection in this group, and effectively guide clinical medication, improve treatment outcomes.
Humans ; Bronchoalveolar Lavage Fluid/microbiology* ; Hematologic Neoplasms/complications* ; Child ; Child, Preschool ; Infant ; Retrospective Studies ; Male ; Female ; Adolescent ; High-Throughput Nucleotide Sequencing ; Pneumonia/microbiology*

Pneumocystis jirovecii pneumonia (PJP) is an opportunistic pulmonary infection that commonly occurs in immunocompromised children. We report a case of infantile leukemia complicated by PJP and review the relevant literature. A summary and analysis of 10 infantile leukemia patients with PJP infection (9 cases reported in the literature and 1 case from our center) showed that PJP mostly occurred in the early stages of chemotherapy (80%, 8/10). The main clinical manifestations were dyspnea (100%, 10/10) and hypoxemia (50%, 5/10), while pulmonary imaging findings lacked specificity. In most cases (50%, 5/10), diagnosis was established by identifying pathogens in bronchoalveolar lavage fluid under microscopy. In our case, diagnosis was confirmed using targeted next-generation sequencing (tNGS) of bronchoalveolar lavage fluid. Treatment with intravenous sulfamethoxazole complex was administered in 8 patients, all of whom eventually recovered. PJP may occur in the early stages of chemotherapy for infantile leukemia, thus early prevention is necessary. tNGS facilitates early diagnosis of PJP, and sulfamethoxazole complex remains an effective therapeutic option.
Humans ; Infant ; Bronchoalveolar Lavage Fluid/microbiology* ; Immunocompromised Host ; Leukemia/complications* ; Pneumocystis carinii/isolation & purification* ; Pneumonia, Pneumocystis/diagnosis* ; Trimethoprim, Sulfamethoxazole Drug Combination/therapeutic use*

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

Pneumocystis, an important opportunistic fungal pathogen that parasitizes in multiple mammalian lungs, may cause life-threatening Pneumocystis pneumonia (PCP) and even death among immunocompromised individuals. With the rapid development of high-throughput sequencing and multi-omics technologies, systematic comparative analyses of genome, transcriptome, and whole-genome sequencing results demonstrate that Pneumocystis is a type of obligate biotrophic fungi, and requires obtaining nutrition from hosts. In addition, sexual reproduction is an essential process for Pneumocystis survival, production and transmission, and asexual reproduction facilitates Pneumocystis survival, which provides new insights into understanding of the whole developmental process of Pneumocystis in the host lung and inter-host transmission of Pneumocystis. This review summarizes the advances in the reproduction mode of Pneumocystis and underlying mechanisms, which provides insights into prevention and treatment of PCP, notably for the prophylaxis against nosocomial transmission of PCP.
Humans ; Lung/microbiology* ; Pneumocystis/genetics* ; Pneumonia, Pneumocystis/microbiology*

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

Few studies have described the key features and prognostic roles of lung microbiota in patients with severe community-acquired pneumonia (SCAP). We prospectively enrolled consecutive SCAP patients admitted to ICU. Bronchoscopy was performed at bedside within 48 h of ICU admission, and 16S rRNA gene sequencing was applied to the collected bronchoalveolar lavage fluid. The primary outcome was clinical improvements defined as a decrease of 2 categories and above on a 7-category ordinal scale within 14 days following bronchoscopy. Sixty-seven patients were included. Multivariable permutational multivariate analysis of variance found that positive bacteria lab test results had the strongest independent association with lung microbiota (R² = 0.033; P = 0.018), followed by acute kidney injury (AKI; R² = 0.032; P = 0.011) and plasma MIP-1β level (R² = 0.027; P = 0.044). Random forest identified that the families Prevotellaceae, Moraxellaceae, and Staphylococcaceae were the biomarkers related to the positive bacteria lab test results. Multivariable Cox regression showed that the increase in α-diversity and the abundance of the families Prevotellaceae and Actinomycetaceae were associated with clinical improvements. The positive bacteria lab test results, AKI, and plasma MIP-1β level were associated with patients' lung microbiota composition on ICU admission. The families Prevotellaceae and Actinomycetaceae on admission predicted clinical improvements.
Acute Kidney Injury/complications* ; Bacteria/classification* ; Chemokine CCL4/blood* ; Community-Acquired Infections/microbiology* ; Humans ; Lung ; Microbiota/genetics* ; Pneumonia, Bacterial/diagnosis* ; Prognosis ; RNA, Ribosomal, 16S/genetics*

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Air Microbiology ; Bacteria/isolation & purification* ; Child ; Child, Preschool ; China/epidemiology* ; DNA, Bacterial/analysis* ; DNA, Ribosomal/analysis* ; Female ; Humans ; Infant ; Infant, Newborn ; Male ; Middle Aged ; Pneumonia, Bacterial/microbiology* ; Risk Assessment/methods* ; Young Adult

Adult ; Anti-Bacterial Agents/therapeutic use* ; COVID-19/drug therapy* ; Catheter-Related Infections/microbiology* ; China ; Drug Resistance, Multiple, Bacterial ; Drugs, Chinese Herbal/therapeutic use* ; Humans ; Intubation, Intratracheal ; Male ; Pneumonia, Viral/drug therapy* ; Prosthesis-Related Infections/microbiology* ; SARS-CoV-2