Mp Infection Research Articles

Mycoplasma pneumoniae regulates the expression of GP130 in lung epithelial cells through apoptosis and TLR4/ NF-κB pathway during infection

In previous study, lower levels of serum GP130 were reported in children with MPP. GP130 is an important signal transducer, the down regulation of which may influence host immune responses. In this study, we aimed to analyze the regulatory mechanism of GP130 during MP infection. Firstly, the mRNA and protein levels of GP130 both decrease and then increase with increasing multiplicity of infection (MOI: 1 to 40) of MP. The lowest levels of GP130 were detected at MOI of 5. Then, heat treated MP but not trypsin treated MP or MP extracted proteins show regulatory effect to the expression of GP130. These indicate that the down regulation of GP130 is related to protein mediate adhesion process of MP. Gene expression analysis revealed that MP affected apoptosis and the TLR4 pathway in infected cells, and the mRNA level of IL-6 was correlated with that of GP130. Further, Z-VAD-FMK (pan-caspase inhibitor) can suppress the apoptosis induced by MP infection and restore GP130 at protein level. Further studies revealed that MP infection promoted TLR4 internalization but did not activate the NF-κB pathway. The levels of surface TLR4 showed correlation with the transcription of IL-6 and GP130. TAK242 (TLR4 inhibitor) and PS341 (proteasome inhibitor) can restore the decreased transcription of GP130, both of which were able to promote NF-κB pathway activation in MP-infected cells. These suggested that the regulation of TLR4/NF-κB pathway and induced apoptosis post MP infection are involved in the down-regulation of GP130 at transcription and protein levels, respectively.

Analyzing infections caused by 11 respiratory pathogens in children: Pre‐ and post‐COVID‐19 pandemic trends in China

AbstractWith the lifting of coronavirus disease 2019 (COVID‐19) restrictions in December 2022 in China, the population was widely infected with COVID‐19. We aim to analyzed changes in the epidemiological characteristics of other respiratory pathogens in children before and after the COVID‐19 pandemic. We conducted a retrospective analysis of 44 704 children with acute respiratory infections who underwent 11 respiratory pathogen tests based on multiplex polymerase chain reaction between February and December in both 2022 and 2023. The total pathogen detection rate (24861, 74.80% vs. 6423, 56.01%; p = 0.000) and detection rates of coinfection (4059, 12.21% vs. 676, 5.89%; p = 0.000) in 2023 was significantly higher than that in 2022. The detection rates of influenza A (2567, 7.72% vs. 222, 1.94%; p = 0.000), influenza B (383, 1.15% vs. 37, 0.32%; p = 0.000), human parainfluenza virus (2175, 6.54% vs. 602, 5.25%; p = 0.000), human metapneumovirus (1354, 4.07% vs. 346, 3.01%; p = 0.000), respiratory syncytial virus (3148, 9.47% vs. 870, 7.59%; p = 0.000), and Mycoplasma pneumonia (MP; 9494, 28.56% vs. 1790, 15.61%; p = 0.000) in 2023 were significantly higher than those in 2022, whereas the detection rates of human adenovirus (1124, 3.38% vs. 489, 4.26%; p = 0.000) and human bocavirus (629, 1.89% vs. 375, 3.27%; p = 0.000) were significantly lower than those in 2022. Chlamydia, human rhinovirus, and human coronavirus showed similar detection rates between 2023 and 2022. In 2023, the influenza virus and human parainfluenza virus regained seasonal characteristic, an outbreak of MP infection occurred, the epidemic season of respiratory syncytial virus changed, and the proportion of children with acute respiratory infection aged 0–28 days and over 3 years old increased. Influenza B, metapneumovirus, and human bocavirus were detected in children aged 0–28 days in 2023, but not in 2022. After the COVID‐19 pandemic, we should be alert to the increase of respiratory diseases and the change of epidemic season and susceptible age.

Macrolide-resistant mycoplasma pneumoniae infection in children observed during a period of high incidence in Henan, China

ObjectiveMycoplasma pneumoniae (Mp) is one of the major pathogens that causes respiratory tract infections, and macrolide resistance has increased rapidly in recent years due to the inappropriate use of macrolides in northeastern Asia. In the present study, we aimed to investigate Mp infection and macrolide resistance during a period of high incidence of Mp infection in Henan, China. MethodsA total of 29473 suspected children with Mp infection were enrolled in the study from July to December 2023. Throat swab specimens were collected from all the study subjects, and real-time PCR was performed to detect the Mp-DNA and macrolide resistance-associated A2063G or A2064G mutations. ResultsThe overall percentage of Mp-DNA-positive patients was 51.1 %, and the percentage of macrolide-resistant strains was 91 %. The rate of macrolide resistance remained stable from July to December. The Mp-DNA positivity rates among the different age groups from low to high were 0–1, 1–3, 3–6, 10–18 and 6–10 years. The macrolide resistance rate was the lowest in the 0–1 age group and highest in the 6–10 age group. No difference in the rate of macrolide resistance was observed between male and female children. ConclusionsThe macrolide resistance rate of Mp did not change during the investigated period of high incidence of infection, and no sex difference existed. The macrolide resistance rate of Mp was the lowest in children under 1 year old.

Post-pandemic trends: Epidemiological and etiological insights into acute respiratory infections in southern China

Data on people suspected with acute respiratory infections (ARIs) from August 2022 to December 2023 in southern China were analyzed. Following the COVID-19 pandemic, the positive detection rates of respiratory pathogens increased to 56.9%. Influenza A virus (IAV) emerged as the predominant prevalence pathogen (52.1%), followed by Mycoplasma pneumoniae (Mp: 21.2%), and SARS-CoV-2 (11.6%). Mp, IAV, and Human rhinovirus (HRV) infection were the primary etiologies of ARIs patients under age 18, accounting for 49.4%, 48.6%, and 21.7%, respectively. Mp, HRV, Respiratory syncytial virus (RSV), and Adenovirus (ADV) contributed to ARIs cases in virtually every month in this group, with Mp being particularly notable for its consistent presence and high co-infection rate (31.0%). IAV was predominant in the 19 to 59 age group (88.6%), SARS-CoV-2 was responsible for most of ARIs in the elderly group (82.5%). This study provides valuable insights into the dynamic nature of respiratory pathogens post COVID-19 era.

Research on the metabolic regulation mechanism of Yangyin Qingfei decoction plus in severe pneumonia caused by Mycoplasma pneumoniae in mice.

Introduction: With amazing clinical efficacy, Yangyin Qingfei Decoction Plus (YQDP), a well-known and age-old Chinese compound made of ten Chinese botanical drugs, is utilized in clinical settings to treat a range of respiratory conditions. This study examines the impact of Yangyin Qingfei Decoction (YQDP) on lung tissue metabolic products in severe Mycoplasma pneumoniae pneumonia (SMPP) model mice and examines the mechanism of YQDP in treating MP infection using UPLC-MS/MS technology. Methods: YQDP's chemical composition was ascertained by the use of Agilent 1260 Ⅱ high-performance liquid chromatography. By using a nasal drip of 1010 CCU/mL MP bacterial solution, an SMPP mouse model was created. The lung index, pathology and ultrastructural observation of lung tissue were utilized to assess the therapeutic effect of YQDP in SMPP mice. Lung tissue metabolites were found in the normal group, model group, and YQDP group using UPLC-MS/MS technology. Using an enzyme-linked immunosorbent test (ELISA), the amount of serum inflammatory factors, such as interleukin-6 (IL-6) and tumor necrosis factor α (TNF-α), was found. Additionally, the protein expression of PI3K, P-PI3K, AKT, P-AKT, NF-κB, and P-NF-κB was found using Western blot. Results: The contents of chlorogenic acid, paeoniflorin, forsythrin A, forsythrin, and paeonol in YQDP were 3.480 ± 0.051, 3.255 ± 0.040, 3.612 ± 0.017, 1.757 ± 0.031, and 1.080 ± 0.007mg/g respectively. YQDP can considerably lower the SMPP mice's lung index (p < 0.05). In the lung tissue of YQDP groups, there has been a decrease (p < 0.05) in the infiltration of inflammatory cells at varying concentrations in the alveoli compared with the model group. A total of 47 distinct metabolites, including choline phosphate, glutamyl lysine, L-tyrosine, 6-thioinosine, Glu Trp, 5-hydroxydecanoate, etc., were linked to the regulation of YQDP, according to metabolomics study. By controlling the metabolism of porphyrins, pyrimidines, cholines, fatty acids, sphingolipids, glycerophospholipids, ferroptosis, steroid hormone biosynthesis, and unsaturated fatty acid biosynthesis, enrichment analysis suggested that YQDP may be used to treat SMPP. YQDP can lower the amount of TNF-α and IL-6 in model group mice as well as downregulate P-PI3K, P-AKT, and P-NF-κB expression (p < 0.05). Conclusion: A specific intervention effect of YQDP is observed in SMPP model mice. Through the PI3K/Akt/NF-κB signaling pathways, YQDP may have therapeutic benefits by regulating the body's metabolism of α-Linoleic acid, sphingolipids, glycerophospholipids, arachidonic acid, and the production of unsaturated fatty acids.

Establishment and Performance Evaluation of Multiplex PCR-Dipstick DNA Chromatography for Mycoplasma pneumoniae and Chlamydia pneumoniae Rapid Detection.

Nasopharyngeal swab samples of 300 children with an acute respiratory tract infection were detected by a multiplex PCR-dipstick chromatography assay, and the results were compared with the DNA sequencing and serum IgM antibody assay. A multiplex PCR-dipstick DNA assay can specifically detect Mycoplasma pneumoniae and Chlamydia pneumoniae and shows a good specificity, with a minimum detection limit of 10 CFU/mL, respectively. Using DNA sequencing results as the gold standard, the sensitivity, specificity, positive predictive value, and negative predictive value of the multiplex PCR-dipstick DNA chromatography assay for the diagnosis of Mycoplasma pneumoniae were 96.61%, 100%, 100%, and 99.18% respectively, and those of Chlamydia pneumoniae were 95.24%, 100%, 100%, and 99.64% respectively. There was no statistical significance MP and CP diagnosis by the multiplex PCR-dipstick DNA assay and DNA sequencing (MP: P = 0.5; CP: P = 1.0), and the two assays had very high statistical consistency (MP: kappa = 0.979; CP: kappa = 0.974). The positive rate of the multiplex PCR-dipstick chromatography assay was significantly higher than that of the serum IgM antibody assay, with MP (17.7% vs. 13.3%), CP (5.7% vs. 3.3%), and mixed infection of MP and CP (1.3% vs. 0.67%). A multiplex PCR-dipstick chromatography assay was successfully established for the joint detection of Mycoplasma pneumoniae and Chlamydia pneumoniae within 2 hours. It is simple, fast, sensitive, accurate, cost-effective with good diagnostic performance, which can be used for small laboratories and point-of-care diagnosis.

The Impact of CC16 on Pulmonary Epithelial-Driven Host Responses during Mycoplasma pneumoniae Infection in Mouse Tracheal Epithelial Cells.

Club Cell Secretory Protein (CC16) plays many protective roles within the lung; however, the complete biological functions, especially regarding the pulmonary epithelium during infection, remain undefined. We have previously shown that CC16-deficient (CC16-/-) mouse tracheal epithelial cells (MTECs) have enhanced Mp burden compared to CC16-sufficient (WT) MTECs; therefore, in this study, we wanted to further define how the pulmonary epithelium responds to infection in the context of CC16 deficiency. Using mass spectrometry and quantitative proteomics to analyze proteins secreted apically from MTECs grown at an air-liquid interface, we investigated the protective effects that CC16 elicits within the pulmonary epithelium during Mycoplasma pneumoniae (Mp) infection. When challenged with Mp, WT MTECs have an overall reduction in apical protein secretion, whereas CC16-/- MTECs have increased apical protein secretion compared to their unchallenged controls. Following Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) assessment, many of the proteins upregulated from CC16-/- MTECS (unchallenged and during Mp infection) were related to airway remodeling, which were not observed by WT MTECs. These findings suggest that CC16 may be important in providing protection within the pulmonary epithelium during respiratory infection with Mp, which is the major causative agent of community-acquired pneumoniae.

Comparison of serodiagnosis methods for community-acquired Mycoplasma pneumoniae respiratory tract infections in children.

This study aimed to evaluate the diagnostic value of chemiluminescence immunoassay (CLIA), passive particle agglutination (PPA), and indirect immunofluorescence assay (IFA) in detecting Mycoplasma pneumoniae infection in children. Serum samples from 165 children with acute community-acquired respiratory tract infections were examined using CLIA, PPA, and IFA, and consistency coefficient, specificity, and sensitivity were analyzed. Compared with the PPA (titer ≥ 1:160), the consistency coefficients of the immunoglobulin(Ig)M-CLIA, immunoglobulin(Ig)G-CLIA and IgM-IFA methods were 93.94%, 75.76%, and 83.64%, respectively. The positive likelihood ratio (PLR) and specificity of IgM-CLIA was 19.40 and 95.49%, respectively. The consistency coefficient of (IgM+IgG)-CLIA and PPA (titer ≥ 1:160) was 89.1%, and the sensitivity and negative predictive value of (IgM+IgG)-CLIA were 96.88% and 98.94%, respectively. CLIA MP-IgM has high concordance with PPA, and its specificity and sensitivity are higher than those of CLIA MP-IgG and IFA MP-IgM, suggesting its better diagnosis of early MP infection. The sensitivity and negative predictive value of CLIA MP (IgM+IgG) were higher than those of PPA or IFA, indicating that it should be considered as a priority in the diagnosis of MP infection.

The clinical significance of macrolide resistance in pediatric Mycoplasma pneumoniae infection during COVID-19 pandemic.

Mycoplasma pneumoniae (MP) is a commonly occurring pathogen causing community-acquired pneumonia (CAP) in children. The global prevalence of macrolide-resistant MP (MRMP) infection, especially in Asian regions, is increasing rapidly. However, the prevalence of MRMP and its clinical significance during the COVID-19 pandemic is not clear. This study enrolled children with molecularly confirmed macrolide-susceptible MP (MSMP) and MRMP CAP from Beijing Children's Hospital Baoding Hospital, Capital Medical University between August 2021 and July 2022. The clinical characteristics, laboratory findings, chest imaging presentations, and strain genotypes were compared between patients with MSMP and MRMP CAP. A total of 520 hospitalized children with MP-CAP were enrolled in the study, with a macrolide resistance rate of 92.7%. Patients with MRMP infection exhibited more severe clinical manifestations (such as dyspnea and pleural effusion) and had a longer hospital stay than the MSMP group. Furthermore, abnormal blood test results (including increased LDH and D-dimer) were more common in the MRMP group (P<0.05). Multilocus variable-number tandem-repeat analysis (MLVA) was performed on 304 samples based on four loci (Mpn13-16), and M3562 and M4572 were the major types, accounting for 74.0% and 16.8% of the strains, respectively. The macrolide resistance rate of M3562 strains was up to 95.1%. The prevalence of MRMP strains in hospitalized CAP patients was extremely high in the Baoding area, and patients infected with MRMP strains exhibited more severe clinical features and increased LDH and D-dimer. M3562 was the predominant resistant clone.

Poor accuracy of single serological IgM tests in children with suspected acute Mycoplasma pneumoniae infection in Guangzhou, China.

Introduction. Early and accurate diagnosis of Mycoplasma pneumoniae (MP) infection of children with pneumonia is at the core of treatment in clinical practice.Gap Statement. Serological immunoglobulin M (IgM) tests for MP infection of children in south China have been rarely described.Aim. To assess the diagnostic performance and clinical application of serodiagnosis of MP infection in paediatric pneumonia patients.Methodology. Serum samples from 144 children diagnosed with MP pneumonia were subjected to a particle agglutination (PA)-based IgM assay. Meanwhile, we used an established suspension array as the reference standard method for the detection of MP DNA in bronchoalveolar lavage fluid (BALF) from all patients to assess the reliability of serological assays.Results. When running immunological testing in single serum samples, 80.6 %(79/98) of cases were diagnosed with MP infection, whereas only 55 (56.1 %) cases were positive in MP DNA analysis. Furthermore, single serum tests for IgM during acute MP infection resulted in 85.5 % (47/55) sensitivity and 25.6 % (11/43) specificity. Nevertheless, immunological testing and MP DNA analysis yielded the same results when paired sera were available for MP IgM antibody testing.Conclusion. Paired serological IgM assays are necessary for the determination of an acute MP infection, whereas single serological IgM testing is unreliable. Moreover, even a short interval of two MP serological tests works well.

Aspergillus oryzae Fermentation Extract Alleviates Inflammation in Mycoplasma pneumoniae Pneumonia.

The filamentous fungus Aspergillus oryzae, also known as koji mold, has been used for centuries in the production of fermented foods in East Asia. A. oryzae fermentation can produce enzymes and metabolites with various bioactivities. In this study, we investigated whether A. oryzae fermentation extract (AOFE) has any effect on Mycoplasma pneumoniae (Mp) pneumonia. We performed solid-state fermentation of A. oryzae and obtained the ethanol extract. AOFE was analyzed by HPLC, and the major component was identified to be kojic acid. In vitro, AOFE suppressed Mp growth and invasion into A549 lung epithelial cells as determined by the gentamicin protection assay. AOFE treatment also suppressed Mp-stimulated production of tumor necrosis factor (TNF)-α and interleukin (IL)-6 at mRNA and protein levels in murine MH-S alveolar macrophages. In a mouse model of Mp pneumonia, Mp infection induced a marked pulmonary infiltration of neutrophils, which was significantly reduced in mice pre-treated orally with AOFE. AOFE administration also suppressed the production of proinflammatory cytokines and chemokines in the lungs. Collectively, our results show that AOFE has the potential to be developed into a preventive/therapeutic agent for Mp pneumonia.

The Association between Mycoplasma pneumoniae Genotype and Cutaneous Disease.

Mycoplasma pneumoniae (Mp) can cause several extrapulmonary manifestations, most frequently dermatological ones. It is largely unknown whether Mp genotype determines Mp-induced cutaneous disease. The aim of our study was to assess the association between Mp genotype and this clinical outcome. We performed a retrospective study of children referred with signs of acute Mp infection from 1 January 2014 to 31 December 2014. We compared the characteristics of children presenting as cutaneous disease, upper (URTI) and lower respiratory tract infection (LRTI). In addition, we separately analyzed the data of patients presenting with Mp-induced cutaneous disease. We evaluated data from 435 patients (mean age 7.3 years, SD 3.4 years; 52.0% boys) who had Mp PCR-positive pharyngeal swab, P1 genotype and/or multilocus variable-number tandem-repeat analysis (MLVA) genotype defined and no viral co-detection, presenting as cutaneous disease (38/435), URTI (46/435) or LRTI (351/435). The majority of patients had urticarial (55%, 21/38) or maculopapular eruptions (37%, 14/38). We found no association between Mp genotype and clinical outcome of cutaneous disease, nor any specific dermatological presentation. In the group with cutaneous disease, 18% (7/38) required hospital admission because of rash. We found that infection with MLVA-3,6,6,2 strains was more common in admitted patients than in outpatients (40% vs. 4%, p = 0.017) and significantly affected the likelihood of hospital admission in a logistic regression model. The results of our cohort study suggest that Mp genotype does not determine Mp-induced cutaneous disease or a specific dermatological presentation. Nevertheless, infections with certain MLVA strains could induce more severe cutaneous disease requiring hospitalization.

Visual detection of Mycoplasma pneumoniae by the recombinase polymerase amplification assay coupled with lateral flow dipstick

Mycoplasma pneumoniae (Mp) is a common cause of respiratory infections in school-age children. In the present study, a recombinase polymerase amplification (RPA) assay combined with lateral flow dipstick (LFD) was developed for diagnosis of Mp. Specific primers and a probe were designed for the Mp p1 gene. The optimal reaction conditions of the RPA-LFD assay were 37 °C and 25 min. The minimal detection limit of the RPA assay was 10 DNA molecules. The RPA method had no cross-reaction with the other 14 common pathogens tested. The practicability of the assay for detecting Mp in clinical samples from the patients suspected to be Mp infection was also determined. The nucleic acids of the clinical samples were extracted by the DNA Rapid extraction reagent which took about 10 min. The clinical specimens were detected by the RPA method, and the result showed high agreement with that of the qPCR commercial kit. The RPA-LFD method with high sensitivity and specificity is easy to perform and is an alternative method for field detection in resources-limited settings.

Laboratory analysis of positive rate of Mycoplasma pneumoniae antibody among 53,273 children with respiratory tract infections in Xi’an from 2017 to 2020

BackgroundMycoplasma pneumoniae (Mp) is an important pathogen that causes respiratory tract infections in children. Data on epidemiology of paediatric Mp infection in China are little known. The aim of this study was to investigate the infection of children with respiratory tract infection in Xi’an from 2017 to 2020, and to explore the epidemiological features of paediatric Mp infection in Northwest China during the past 4 years.MethodsA total of 53,273 paediatric patients diagnosed with respiratory tract infection as the first diagnosis were enrolled. Mp antibody was detected using passive agglutination method. Statistical analysis and epidemiological investigation were carried out on the test results according to different years, seasons, ages and genders. The differences among rates were analyzed by the χ2 test. The trends among the rates were analyzed by the Poisson regression.ResultsA total of 14,375 Mp antibody positive patients were detected, with a total positive rate of 26.98%. The rate of Mp infection in 2017 was significantly higher than other years (χ2=431.700; P=0.000), and the rate showed a downward trend year by year [incidence rate ratios (IRR) =0.906; 95% CI: 0.892–0.921; P=0.000]. The rate of Mp infection increased gradually in the order of spring, summer, autumn and winter (IRR =1.078; 95% CI: 1.060–1.097; P=0.000), and peaked in winter (29.08%). As age increased, the positive rate of Mp infection also gradually increased (IRR =1.138; 95% CI: 1.134–1.143; P=0.000). The peak age of Mp infection was between 6 and 12 years, accounting for 51.71%, significantly more compared with other age groups (χ2=4203.000, P=0.000). Female children had significantly higher positive rates than male children (χ2=527.000; P=0.000).ConclusionsMp infection mainly occurs related to year, season, age and gender. Understanding the epidemiological characteristics of paediatric Mp infection can contribute to timely treatment and diagnosis, and may improve the prognosis of children with Mp infection.

Metabolism Characteristics of Mycoplasma pneumoniae Infection in Asthmatic Children.

Studies have shown that Mycoplasma pneumoniae (Mp) infection can aggravate symptoms in asthmatics. However, the mechanism by which Mp infection exacerbates asthma remains unclear. Metabolomics can help identify the mechanism of Mp aggravating asthma in children, thereby providing more a potential target for improving clinical treatment programs. In this article, we analyzed the metabolic level of patients to explain how Mp aggravates asthma in children. We divided the subjects into the asthma, Mp infection, asthma combined with Mp infection and healthy groups. Patients' peripheral blood was collected for metabolic and interaction analysis. Cytokine levels were measured via serum and exhaled breath condensate (EBC). A total of 150 participating subjects were divided into four groups after exclusion. We found out that there were different metabolic pathways between the healthy and disease groups. The major pathways of both asthma and asthma combined with Mp infection were valine, leucine and isoleucine biosynthesis; malate-aspartate shuttle was the main differential pathway for Mp infection. Moreover, even though three disease groups involved 81 metabolites at the same time, compared with asthma combined with Mp infection, 2 single disease groups still involved different amino acid pathways (phenylalanine, tyrosine and tryptophan biosynthesis; valine, leucine and isoleucine biosynthesis). Interaction analysis showed that Mp infection in asthmatic patients not only activated cytokines, but also activated Toll-like receptors (TLRs) 2 and 6. Finally, the levels of interleukin (IL)-4, IL-8, IL-13 and tumor necrosis factor-α in EBC with asthma combined with Mp infection were significantly higher than the 2 single disease groups. Mp infection in asthmatic children can cause changes in the levels of various amino acids in the body, which were enriched in the pathways such as valine, leucine and isoleucine biosynthesis. Palmitic acid can activate TLR2, and iloprost reduces IL-10 levels, ultimately leading to the increased airway inflammation.

Increased Total Serum Immunoglobulin E Is Likely to Cause Complications of Mycoplasma pneumoniae Pneumonia in Children.

ObjectiveTo investigate the correlation between serum immunoglobulin E (IgE) levels and the complications in children with Mycoplasma pneumoniae pneumonia (MPP).MethodsA retrospective study of MPP patients hospitalized from May 2019 to July 2021 was performed. We analyzed the clinical manifestations, complications, laboratory findings, and treatments.ResultsA total of 275 patients who met the inclusion criteria were enrolled in the study. We divided patients into two groups based on whether there were complications. Complications occurred in 147 patients, of which pulmonary complications were more common than extrapulmonary complications. The IgE level in the complication group was higher than that in the non-complication group with p = 0.041. Patients with complications of necrotizing pneumonitis, pneumothorax, skin rash, or bronchiolitis obliterans had higher IgE levels. There was no statistically significant difference in IgE levels between pulmonary complications and extrapulmonary complications. The older the age, the greater the probability of complications (p = 0.001). The group with complications was more likely to have chest pain (p = 0.000), while the group without complications was more likely to have wheezing (p = 0.017). The use of bronchoscopy and glucocorticoids was higher in the complication group than in the non-complication group (p = 0.000).ConclusionsMPP patients with higher IgE levels had more severe clinical symptoms and complications. We speculated that IgE might be a biomarker for complications after MP infection.

CC16 Deficiency in the Context of Early-Life Mycoplasma pneumoniae Infection Results in Augmented Airway Responses in Adult Mice.

Studies have shown that club cell secretory protein (CC16) plays important protective roles in the lungs, yet its complete biological functions are unclear. We devised a translational mouse model in order to investigate the impact of early life infections, in the context of CC16 deficiency, on lung function in adult mice. CC16 sufficient (WT) and deficient (CC16-/-) mice were infected with Mycoplasma pneumoniae (Mp) as weanlings and assessed as adults (early life infection model; ELIM) and compared to adult mice infected for only 3 days (adult infection model; AIM). CC16-/- Mp-infected mice had significantly increased airway hyperresponsiveness (AHR) in both models compared to WT mice. However, CC16-/- mice infected in early life (ELIM) displayed significantly increased AHR compared to CC16-/- mice infected in adulthood (AIM). In stark contrast, lung function in ELIM WT mice returned to levels similar to saline-treated controls. While WT mice cleared Mp infection in the ELIM, CC16-/- mice remained colonized with Mp throughout the model, which likely contributed to increased airway remodeling and persistence of Muc5ac expression. When CC16-/- mouse tracheal epithelial cells (MTECs) were infected with Mp, increased Mp colonization and collagen gene expression were also detected compared to WT cells, suggesting that CC16 plays a protective role during Mp infection, in part through epithelial-driven host defense mechanisms.

Mycoplasma pneumoniae infection prediction model for hospitalized community-acquired pneumonia children.

We sought to develop a nomogram to predict Mycoplasma pneumoniae (Mp) infection among hospitalized children with community-acquired pneumonia (CAP) and compare it with another model developed from age and duration of fever. Data on 5904 CAP children who were enrolled at Shanghai Children's Medical Center were retrospectively collected and divided into a training set (n = 4133) and a validation set (n = 1771). The model's performance was determined by concordance index (C-index), calibration curves, Brier scores, and decision curve analyses (DCAs). Akaike information criterion (AIC) and Bayesian information criterion (BIC) were used for model comparisons. Incorporating five factors (age, duration of fever, erythrocyte sedimentation rate, leukocyte count, and neutrophil proportion), the nomogram achieved good C-index values of 0.74 (95% confidence interval [CI]: 0.72-0.76) and 0.75 (95% CI: 0.73-0.78) and good Brier scores of 0.14 (95% CI: 0.13-0.15) and 0.17 (95% CI: 0.15-0.18) in predicting Mp infection in the training and validation cohorts, respectively, and had moderate fitted calibration plots. The DCAs showed good clinical usefulness of the nomogram. Patients were effectively divided into low, medium, and high risk groups by two cut-off score points of the nomogram, 210 and 300. With the lower AIC (3673.5) and BIC (3774.7) value, the model of five predictors is the better model. By using five predictor variables, a simple nomogram of good predictive accuracy for Mp infection and moderate agreements between the actual outcome and the predicted probability was constructed. It could serve as a tool to aid physicians in clinical decision-making processes.

The Level of D-Dimer Is Positively Correlated With the Severity of Mycoplasma pneumoniae Pneumonia in Children.

Objective Mycoplasma pneumoniae pneumonia (MPP) is an important disease in children. Studies have demonstrated that the levels of D-dimer are elevated in some children with MPP, especially those with thrombotic complications. However, the potential association between MPP and D-dimer remains unclear. In our study, we sought to explore the relationship between the levels of plasma D-dimer and clinical characteristics of MPP patients.MethodsRetrospective analysis was conducted on 356 patients who were hospitalized in our hospital for MPP between January 1, 2017, and December 31, 2019. According to the peak value of D-dimer, patients were divided into three groups: the normal group (D-dimer<0.55 mg/L), the mild-moderately elevated group (D-dimer 0.55–5.5 mg/L) and the severely elevated group (D-dimer >5.5 mg/L). The demographic and clinical information, radiological findings, laboratory data, and treatments of patients were compared among different groups.Results106 patients were in the normal group, 204 patients were in the mild-moderately elevated group, and 46 patients were in the severely elevated group. More severe clinical and radiographic manifestations, longer length of fever, hospital stay and antibiotic therapy duration, higher incidences of extra-pulmonary complications, refractory MPP (RMPP), severe MPP (SMPP) were found in the elevated group, when compared with the normal group (P<0.01). Meanwhile, we found that the percentage of neutrophil (N%) and CD8 + lymphocyte (CD8 +%), C-reactive protein (CRP), lactate dehydrogenase (LDH), interleukin (IL)-6, IL-10, and interferon-gamma (IFN-γ) trended higher with increasing D-dimer, whereas the percentage of lymphocyte (L%) and prealbumin (PAB) trended lower (P<0.01). In addition, the proportions of patients requiring oxygen therapy, glucocorticoid, bronchoscopy, immunoglobulin use, thoracentesis, or ICU admission were significantly higher in the severely elevated group than those in the other two groups (P<0.01). Correlation analysis showed that N%, L%, CRP, LDH, IL-10, length of fever, length of stay, and length of antibiotic therapy had strong correlations with the level of D-dimer.ConclusionsMPP patients with higher levels of D-dimer had more severe clinical manifestations and needed longer duration of treatment, which might be closely related to the severity of lung inflammation after MP infection.

Prevalence and clinical characteristics of septicemia in children with Mycoplasma pneumoniae pneumonia.

BackgroundMycoplasma pneumoniae (MP) pneumonia in children can be challenging to treat, and the impact of MP blood infection is unclear. The present study aims to determine the prevalence and clinical characteristics of MP septicemia among pediatric patients.MethodsChildren hospitalized at our center for MP pneumonia between October 2017 and June 2018 were included. Healthy controls visiting our outpatient clinic for regular physical examinations were also enrolled. MP was detected by real-time polymerase chain reaction (qPCR) analysis of plasma and peripheral blood mononuclear cell (PBMC) samples.ResultsSixty-one children with MP pneumonia and 30 healthy children were included. Among children with MP infection, 31 (50.8%) were positive for MP by qPCR (19 in plasma samples, 8 in PBMC samples, and 4 in both). All healthy controls were negative for MP by qPCR.ConclusionsThe prevalence of MP septicemia in children with MP pneumonia is moderate. However, detection of MP in blood samples may have limited clinical value for guiding treatment.