Mycoplasma pneumoniae from the Respiratory Tract and Beyond

Serum IL-17A and IL-6 in paediatric Mycoplasma pneumoniae pneumonia: implications for different endotypes

Paediatric Mycoplasma pneumoniae pneumonia (MPP) is a heterogeneous disease with a diverse spectrum of clinical phenotypes. No studies have demonstrated the relationship between underlying endotypes and clinical phenotypes as well as prognosis about this disease. Thus, we conducted a multicentre prospective longitudinal study on children hospitalized for MPP between June 2021 and March 2023, with the end of follow-up in August 2023. Blood samples were collected and processed at multiple time points. Multiplex cytokine assay was performed to characterize serum cytokine profiles and their dynamic changes after admission. Cluster analysis based on different clinical phenotypes was conducted. Among the included 196 patients, the levels of serum IL-17A and IL-6 showed remarkable variabilities. Four cytokine clusters based on the two cytokines and four clinical groups were identified. Significant elevation of IL-17A mainly correlated with diffuse bronchiolitis and lobar lesion by airway mucus hypersecretions, while that of IL-6 was largely associated with lobar lesion which later developed into lung necrosis. Besides, glucocorticoid therapy failed to inhibit IL-17A, and markedly elevated IL-17A and IL-6 levels may correlate with lower airway obliterans. Our study provides critical relationship between molecular signatures (endotypes) and clustered clinical phenotypes in paediatric patients with MPP.

Challenges in the treatment of pediatric Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is an important cause of community-acquired pneumonia in children and young adolescents. Despite macrolide antibiotics effectiveness as a first-line therapy, persistence of fever and/or clinical deterioration sometimes may complicate treatment and may even lead to severe systemic disease. To date, there is no consensus on alternative treatment options, optimal dosage, and duration for treating severe, progressive, and systemic MP pneumonia after macrolide treatment failure. Macrolide-resistant MP pneumonia and refractory MP pneumonia are the two major complex conditions that are clinically encountered. Currently, the vast majority of MP isolates are resistant to macrolides in East Asia, especially China, whereas in Europe and North America, whereas in Europe and North America prevalence is substantially lower than in Asia, varying across countries. The severity of pneumonia and extrapulmonary presentations may reflect the intensity of the host's immune reaction or the dissemination of bacterial infection. Children infected with macrolide-resistant MP strains who receive macrolide treatment experience persistent fever with extended antibiotic therapy and minimal decrease in MP-DNA load. Alternative second-line agents such as tetracyclines (doxycycline or minocycline) and fluoroquinolones (ciprofloxacin or levofloxacin) may lead to clinical improvement after macrolide treatment failure in children. Refractory MP pneumonia reflects a deterioration of clinical and radiological findings due to excessive immune response against the infection. Immunomodulators such as corticosteroids and intravenous immunoglobulin (IVIG) have shown promising results in treatment of refractory MP pneumonia, particularly when combined with appropriate antimicrobials. Corticosteroid-resistant hyperinflammatory MP pneumonia represents a persistent or recrudescent fever despite corticosteroid therapy with intravenous methylprednisolone at standard dosage.

CONCLUSION

 This report summarizes the clinical significance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drugs, with a stepwise approach to the management of MP pneumonia recommended from the viewpoint of clinical practice.

WHAT IS KNOWN

• Although MP pneumonia is usually a benign self-limited infection with response macrolides as first line therapy, severe life-threatening cases may develop if additional treatment strategies are not effectively implemented. • Macrolide-resistant and refractory MP pneumonia are two conditions that may complicate the clinical course of MP pneumonia, increasing the risk for exacerbation and even death.

WHAT IS NEW

• This report summarizes the clinical relevance of macrolide-resistant and refractory MP pneumonia and discusses the efficacy and safety of alternative drug therapies. • A practical stepwise approach to the management of MP pneumonia is developed based on a comprehensive analysis of existing evidence and expert opinion.

Exploring the pathogenetic mechanisms of Mycoplasmapneumoniae (Review)

Mycoplasmas, the smallest self-replicating prokaryotes without a cell wall, are the most prevalent and extensively studied species in humans. They significantly contribute to chronic respiratory tract illnesses and pneumonia, with children and adolescents being particularly vulnerable. Mycoplasma pneumoniae (M. pneumoniae) infections typically tend to be self-limiting and mild but can progress to severe or even life-threatening conditions in certain individuals. Extrapulmonary effects often occur without pneumonia, and both intrapulmonary and extrapulmonary complications operate through separate pathological mechanisms. The indirect immune-mediated damage of the immune system, vascular blockages brought on by vasculitis or thrombosis and direct harm from invasion or locally induced inflammatory cytokines are potential causes of extrapulmonary manifestations due to M. pneumoniae. Proteins associated with adhesion serve as the primary factor crucial for the pathogenicity of M. pneumoniae, relying on a specialized polarized terminal attachment organelle. The type and density of these host receptors significantly impact the adhesion and movement of M. pneumoniae, subsequently influencing the pathogenic mechanism and infection outcomes. Adjacent proteins are crucial for the proper assembly of the attachment organelle, with variations in the genetic domains of P1, P40 and P90 surfaces contributing to the variability of clinical symptoms and offering new avenues for developing vaccines against M. pneumoniae infections. M. pneumoniae causes oxidative stress within respiratory tract epithelial cells by adhering to host cells and releasing hydrogen peroxide and superoxide radicals. This oxidative stress enhances the vulnerability of host cells to harm induced by oxygen molecules. The lack of superoxide dismutase and catalase of bacteria allows it to hinder the catalase activity of the host cell, leading to the reduced breakdown of peroxides. Lung macrophages play a significant role in managing M. pneumoniae infection, identifying it via Toll-like receptor 2 and initiating the myeloid differentiation primary response gene 88-nuclear factor κΒ signaling cascade. However, the precise mechanisms enabling M. pneumoniae to evade intracellular host defenses remain unknown, necessitating further exploration of the pathways involved in intracellular survival. The present comprehensive review delves into the pathogenesis of M. pneumoniae infection within the pulmonary system and into extrapulmonary areas, outlining its impact.

Increased Severity of Mycoplasma pneumoniae Infections in Spanish Children

BACKGROUND

Since the end of 2023, an elevated incidence and severity of Mycoplasma pneumoniae infections among children in Asia has been noted. Subsequently, this trend was observed in several European countries although limited data are currently available. We conducted a national study to delineate the ongoing M. pneumoniae outbreak in our country.

METHODS

A multicenter retrospective observational study was conducted across 32 hospitals in Spain, encompassing patients under 18 years old hospitalized for M. pneumoniae infection from January 2023 to March 2024. Infection was confirmed by positive polymerase chain reaction and/or by 2 serological tests.

RESULTS

A total of 623 children were included, with 79% of cases diagnosed in the final 3 months of the study period. Pneumonia was the most common diagnosis (87%). Respiratory symptoms were present in 97% of cases, with 62% requiring oxygen supplementation and 14% requiring admission to the pediatric intensive care unit (PICU). Risk factors for PICU admission included the presence of neurological symptoms, hypoxemia and a history of prematurity. Children admitted to the PICU exhibited significantly higher neutrophil counts upon admission.

CONCLUSIONS

We have observed a notable increase in hospital admissions, including PICU support by up to 14%, due to M. pneumoniae infection in our country since November 2023, indicative of a more severe clinical course associated with this pathogen.

Comparative genomic sequencing to characterize Mycoplasma pneumoniae genome, typing, and drug resistance

To analyze the characteristics of Mycoplasma pneumoniae as well as macrolide antibiotic resistance through whole-genome sequencing and comparative genomics. Thirteen clinical strains isolated from 2003 to 2019 were selected, 10 of which were resistant to erythromycin (MIC >64 µg/mL), including 8 P1-type I and 2 P1-type II. Three were sensitive (<1 µg/mL) and P1-type II. One resistant strain had an A→G point mutation at position 2064 in region V of the 23S rRNA, the others had it at position 2063, while the three sensitive strains had no mutation here. Genome assembly and comparative genome analysis revealed a high level of genome consistency within the P1 type, and the primary differences in genome sequences concentrated in the region encoding the P1 protein. In P1-type II strains, three specific gene mutations were identified: C162A and A430G in L4 gene and T1112G mutation in the CARDS gene. Clinical information showed seven cases were diagnosed with severe pneumonia, all of which were infected with drug-resistant strains. Notably, BS610A4 and CYM219A1 exhibited a gene multi-copy phenomenon and shared a conserved functional domain with the DUF31 protein family. Clinically, the patients had severe refractory pneumonia, with pleural effusion, necessitating treatment with glucocorticoids and bronchoalveolar lavage. The primary variations between strains occur among different P1-types, while there is a high level of genomic consistency within P1-types. Three mutation loci associated with specific types were identified, and no specific genetic alterations directly related to clinical presentation were observed.IMPORTANCEMycoplasma pneumoniae is an important pathogen of community-acquired pneumonia, and macrolide resistance brings difficulties to clinical treatment. We analyzed the characteristics of M. pneumoniae as well as macrolide antibiotic resistance through whole-genome sequencing and comparative genomics. The work addressed primary variations between strains that occur among different P1-types, while there is a high level of genomic consistency within P1-types. In P1-type II strains, three specific gene mutations were identified: C162A and A430G in L4 gene and T1112G mutation in the CARDS gene. All the strains isolated from severe pneumonia cases were drug-resistant, two of which exhibited a gene multi-copy phenomenon, sharing a conserved functional domain with the DUF31 protein family. Three mutation loci associated with specific types were identified, and no specific genetic alterations directly related to clinical presentation were observed.

Study on the Correlation Between the Expression of NF-Ƙb in the Alveolar Lavage Fluid of Children with Severe Mycoplasma Pneumoniae Pneumonia, Its Clinical Characteristics, and Cellular Immunity

Objective

This study explored the level of nuclear factor-ƙB (NF-ƙB) in the bronchoalveolar lavage fluid (BALF) of children with severe Mycoplasma Pneumoniae pneumonia (SMPP) and the correlation between NF-ƙB, cellular immunity, and clinical characteristics.

Methods

A total of 41 hospitalized children diagnosed with SMPP were selected and included in the SMPP group, and 13 bronchial foreign bodies (FB) without infection during the same period were included in the FB group. The NF-ƙB in the BALF of participants was detected by enzyme-linked immunosorbent assay. The correlation between NF-ƙB and laboratory findings, cellular immunity, and the clinical features in children with SMPP was analyzed. The differences in chest imaging and bronchoscopy in children with SMPP were observed.

Results

The levels of NF-ƙB were significantly increased in the SMPP group compared with the FB group (P < 0.001). There were correlations between different NF-ƙB pairs in the SMPP group (P < 0.01). Nuclear factor-ƙB (NF-ƙB) correlated with IL-6, the mycoplasma load in BALF, fever peak, length of hospital stay, and sputum suppository (P < 0.05). The higher the intracellular NF-ƙB level in BALF, the lower the CD3+ CD4+ value in peripheral blood (P < 0.05). Intracellular NF-ƙB and total NF-ƙB correlated with pleural effusion, pericardial effusion, and extrapulmonary complications (P < 0.05).

Conclusion

NF-ƙB is involved in airway inflammation changes in children with SMPP. The higher the level of NF-ƙB in the airway, the more severe the clinical manifestations, and the longer the length of hospital stay is likely to be.

Mycoplasma pneumoniae pneumonia-associated thromboembolism with plastic bronchitis: a series of five case reports and literature review

BACKGROUND

Mycoplasma pneumoniae pneumonia is a common respiratory infection among children. However, the occurrence of thromboembolism with plastic bronchitis in association with Mycoplasma pneumoniae pneumonia is extremely rare. This case series presents five cases of children with Mycoplasma pneumoniae pneumonia who developed thromboembolism and plastic bronchitis. The clinical presentation, diagnostic approach, and management strategies are discussed.

METHODS

A retrospective analysis was conducted on medical records from a pediatric hospital. Patient demographics, clinical features, laboratory findings, imaging results, treatment modalities, and outcomes were collected.

RESULTS

The patients in our case series presented with varying degrees of respiratory distress, cough, and fever. Imaging studies revealed evidence of thromboembolism based on pulmonary artery occlusion. Bronchial casts were observed by bronchoscopy. Laboratory tests demonstrated elevated D-dimer levels and fibrinogen degradation products. All patients received a combination of low molecular weight heparin anticoagulation and supportive care.

CONCLUSION

Thromboembolism with plastic bronchitis associated with Mycoplasma pneumoniae pneumonia is a rare but potentially serious complication in children. Prompt recognition and management are crucial for improving patient outcomes. This case series highlights the diverse clinical presentations, diagnostic challenges, and treatment strategies for this unique clinical entity. Further research is needed to better understand the pathogenesis and optimal management of this condition.

The Therapeutic Potential of Neutrophil Extracellular Traps and NLRP3 Inflammasomes in Mycoplasma pneumoniae Pneumonia

INTRODUCTION

Mycoplasma pneumoniae (MP) is the most common pathogen of community-acquired pneumonia in children. However, the role of neutrophil extracellular traps (NETs) in the pathogenesis of MP is unclear.

METHODS

Both the level of NETs were detected between the 60 MP pneumonia patients and 20 healthy controls, whose the clinical characteristics were compared. Additionally, NETs formation induced by community-acquired respiratory distress syndrome (CARDS) toxin was also analyzed through transcriptome sequencing.

RESULTS

The levels of cell-free DNA, Cit-H3, and MPO-DNA complexes were significantly increased in the patients with MP pneumonia. Importantly, both cell-free DNA and LDH were higher in hospitalized patients with severity than those without severity. In addition, CARDS toxin induced the NETs formation in vitro and in vivo. Transcriptomics GO and KEGG pathway analysis indicate that NOD like receptor signaling pathway and Toll-like receptor signaling pathway are significantly enriched. Finally, we found that DNase I significantly attenuated the higher levels of Cit-H3, and up-regulation of interleukin-1β (IL-1β) and interleukin-18 (IL-18) by down-regulating the expression of NLRP3 and Caspase1(p20) in the lung tissues.

DISCUSSION

These results indicate that inhibiting excessive activation of NLRP3 inflammasomes, and NETs formation may alleviate MP pneumonia.

Meta-analysis of combined azithromycin and inhaled budesonide treatment for Chinese pediatric patients with mycoplasma pneumonia

BACKGROUND

Budesonide, capable of reducing vascular permeability, suppressing mucus secretion, and alleviating edema and spasms, is widely used in China for combined infectious disease treatment. This study assesses budesonide's efficacy and safety as an adjunct to azithromycin in pediatric Mycoplasma pneumonia management in China, aiming to establish a strong theoretical foundation for its clinical application.

METHODS

We conducted a comprehensive search for qualifying studies across 5 English databases and 4 Chinese databases, covering publications until October 31, 2023. Endpoint analyses were performed using standard software (Stata Corporation, College Station, TX). This study was conducted in compliance with the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.

RESULTS

A total of 24 randomized controlled trials were involved in the current study, including 2034 patients. Our findings indicate that the combination of budesonide with azithromycin for the treatment of pediatric Mycoplasma pneumonia delivers superior therapeutic efficacy (Intravenous: odds ratio [OR], 0.156, P < .001; Sequential: OR, 0.163, P = .001; Oral: OR, 0.139, P < .001), improved pulmonary function (Forced expiratory volume in 1 second: weighted mean differences [WMD], -0.28, P = .001; Peak expiratory flow: WMD, -0.554, P = .002; Forced vital capacity: WMD, -0.321, P < .001), diminished lung inflammation (IL-6: WMD, 4.760, P = .002; c-reactive protein: WMD, 5.520, P < .001; TNF-α: WMD, 9.124, P < .001), reduced duration of fever, faster resolution of cough and rales, all without increasing the occurrence of adverse events.

CONCLUSION

The combination of budesonide and azithromycin demonstrates enhanced therapeutic effectiveness, promotes improved pulmonary function, shortens the duration of symptoms, and effectively mitigates the overexpression of inflammatory factors like c-reactive protein, TNF-α, and IL-6, all without an associated increase in adverse reactions in pediatric mycoplasma pneumonia.

Post COVID-19 Pandemic Increased Detection of Mycoplasma Pneumoniae in Adults Admitted to the Intensive Care

Background: Mycoplasma pneumoniae (M. pneumoniae) infections can progress to severe respiratory complications, necessitating intensive care treatment. Recent post COVID-19 pandemic surges underscore the need for timely diagnosis, given potential diagnostic method limitations. Methods: A retrospective case series analysis was conducted on M. pneumonia PCR-positive patients admitted to two Dutch secondary hospitals' ICUs between January 2023 and February 2024. Clinical presentations, treatments, outcomes, and mechanical ventilation data were assessed. Results: Seventeen ICU-admitted patients were identified, with a median age of 44 years, primarily due to hypoxia. Non-invasive ventilation was effective for most, while five required invasive mechanical ventilation. None of the patients required extracorporeal membrane oxygenation. No fatalities occurred. Post-PCR, treatment was adjusted to doxycycline or azithromycin; seven received steroid treatment. Discussion: Increased ICU admissions for M. pneumoniae infection were observed. Diverse clinical and radiological findings emphasize heightened clinical awareness. Early molecular diagnostics and tailored antibiotic regimens are crucial since beta-lactam antibiotics are ineffective. Conclusion: This study highlights the escalating challenge of severe M. pneumoniae infections in ICUs, necessitating a multifaceted approach involving accurate diagnostics, vigilant monitoring, and adaptable treatment strategies for optimal patient outcomes.

Mycoplasma pneumoniae detections in children with lower respiratory infection before and during the COVID-19 pandemic: a large sample study in China from 2019 to 2022

BACKGROUND

Nonpharmaceutical interventions (NPIs) implemented to reduce the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have suppressed the spread of other respiratory viruses during the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to explore the epidemiological trends and clinical characteristics of Mycoplasma pneumoniae (MP) infection among inpatient children with lower respiratory tract infection (LRTI) before and during the COVID-19 pandemic, and investigate the long-term effects of China's NPIs against COVID-19 on the epidemiology of MP among inpatient children with LRTI.

METHODS

Children hospitalised for LRTI at the Department of Pulmonology, The Children's Hospital, Zhejiang University School of Medicine (Hangzhou, China) between January 2019 and December 2022 were tested for common respiratory pathogens, including Mycoplasma pneumoniae (MP), Chlamydia trachomatis (CT) and other bacteria. Clinical data on age, sex, season of onset, disease spectrum, and combined infection in children with MP-induced LRTI in the past 4 years were collected and analysed.

RESULTS

Overall, 15909 patients were enrolled, and MP-positive cases were 1971 (34.0%), 73 (2.4%), 176 (5.8%), and 952 (20.6%) in 2019, 2020, 2021, and 2022, respectively, with a significant statistical difference in the MP-positive rate over the 4 years (p <0.001). The median age of these children was preschool age (3-6 years), except for 2022, when they were school age (7-12 years), with statistical differences. Comparing the positive rates of different age groups, the school-age children (7-12 years) had the highest positive rate, followed by the preschoolers (3-6 years) in each of the 4 years. Compared among different seasons, the positive rate of MP in children with LRTI was higher in summer and autumn, whereas in 2020, it was highest in spring. The monthly positive rate peaked in July 2019, remained low from 2020 to 2021, and rebounded until 2022. Regarding the disease spectrum, severe pneumonia accounted for the highest proportion (46.3%) pre-pandemic and lowest (0%) in 2020.

CONCLUSION

Trends in MP detection in children with LRTIs suggest a possible correlation between COVID-19 NPIs and significantly reduced detection rates. The positivity rate of MP gradually rose after 2 years. The epidemic season showed some differences, but school-age children were more susceptible to MP before and during the COVID-19 pandemic.

Marine-Derived Sulfated Glycans Inhibit the Interaction of Heparin with Adhesion Proteins of Mycoplasma pneumoniae

Mycoplasma pneumoniae, a notable pathogen behind respiratory infections, employs specialized proteins to adhere to the respiratory epithelium, an essential process for initiating infection. The role of glycosaminoglycans, especially heparan sulfate, is critical in facilitating pathogen-host interactions, presenting a strategic target for therapeutic intervention. In this study, we assembled a glycan library comprising heparin, its oligosaccharide derivatives, and a variety of marine-derived sulfated glycans to screen the potential inhibitors for the pathogen-host interactions. By using Surface Plasmon Resonance spectroscopy, we evaluated the library's efficacy in inhibiting the interaction between M. pneumoniae adhesion proteins and heparin. Our findings offer a promising avenue for developing novel therapeutic strategies against M. pneumoniae infections.

Quantitative radiomics analysis of imaging features in adults and children Mycoplasma pneumonia

Purpose

This study aims to explore the value of clinical features, CT imaging signs, and radiomics features in differentiating between adults and children with Mycoplasma pneumonia and seeking quantitative radiomic representations of CT imaging signs.

Materials and methods

In a retrospective analysis of 981 cases of mycoplasmal pneumonia patients from November 2021 to December 2023, 590 internal data (adults:450, children: 140) randomly divided into a training set and a validation set with an 8:2 ratio and 391 external test data (adults:121; children:270) were included. Using univariate analysis, CT imaging signs and clinical features with significant differences (p < 0.05) were selected. After segmenting the lesion area on the CT image as the region of interest, 1,904 radiomic features were extracted. Then, Pearson correlation analysis (PCC) and the least absolute shrinkage and selection operator (LASSO) were used to select the radiomic features. Based on the selected features, multivariable logistic regression analysis was used to establish the clinical model, CT image model, radiomic model, and combined model. The predictive performance of each model was evaluated using ROC curves, AUC, sensitivity, specificity, accuracy, and precision. The AUC between each model was compared using the Delong test. Importantly, the radiomics features and quantitative and qualitative CT image features were analyzed using Pearson correlation analysis and analysis of variance, respectively.

Results

For the individual model, the radiomics model, which was built using 45 selected features, achieved the highest AUCs in the training set, validation set, and external test set, which were 0.995 (0.992, 0.998), 0.952 (0.921, 0.978), and 0.969 (0.953, 0.982), respectively. In all models, the combined model achieved the highest AUCs, which were 0.996 (0.993, 0.998), 0.972 (0.942, 0.995), and 0.986 (0.976, 0.993) in the training set, validation set, and test set, respectively. In addition, we selected 11 radiomics features and CT image features with a correlation coefficient r greater than 0.35.

Conclusion

The combined model has good diagnostic performance for differentiating between adults and children with mycoplasmal pneumonia, and different CT imaging signs are quantitatively represented by radiomics.

Characteristics and Outcomes of Mycoplasma Pneumoniae Pneumonia Associated with Pulmonary Embolism and Necrotizing Pneumonia in Children

Purpose

To explore the clinical characteristics, treatment, and long-term prognosis of mycoplasma pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) in children.

Patients and Methods

The medical records of 16 children who were diagnosed with MPP associated with PE between January 2016 and January 2023 at Children's Hospital, Zhejiang University School of Medicine were retrospectively reviewed.

Results

The average age patients were 8.24 ± 1.99 years. All cases were diagnosed with refractory mycoplasma pneumoniae pneumonia (RMPP) and presented complications in the form of necrotizing pneumonia (NP). The main symptoms observed were cough and fever (n = 16, 100%), chest pain (n = 8, 50%), dyspnea (n = 8, 50%), and hemoptysis (n = 4, 25%). In these cases, 12 patients had involvement of the pulmonary artery, 3 patients experienced issues with the pulmonary vein, and 1 patient had simultaneous involvement of both the pulmonary artery and pulmonary vein. Among the 12 pulmonary artery embolism cases, 6 involved the right pulmonary artery, 4 involved the left pulmonary artery, and 2 involved both the right and left pulmonary arteries. The mean D-dimer level was 8.50 ± 4.76 mg/L. All patients received anticoagulant therapy, and after treatment, there was a significant improvement in their symptoms and lung lesions.

Conclusion

Children with RMPP, chest pain, hemoptysis, and elevated D-dimer levels should be closely monitored for the potential development of PE. The co-occurrence of MPP and PE often involves the presence of NP. In cases of confirmed PE, anticoagulation therapy may be a suitable consideration. PE and NP resulting from MPP generally had a favorable overall prognosis.

Concomitant Central and Peripheral Nervous System Involvement Associated With Mycoplasma pneumoniae Infection in Pediatric Patients: Two Case Reports and Literature Review

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is a common pathogen for community-acquired pneumonia and is also implicated in a broad array of extra-pulmonary manifestations. M. pneumoniae infection is rarely associated with concurrent central nervous system (CNS) and peripheral nervous system (PNS) involvement in children.

METHODS

We report 2 patients who presented with acute encephalitis and polyradiculitis due to M. pneumoniae infection and review the literature to discuss the pathogenesis and treatment of concomitant CNS and PNS involvement associated with M. pneumoniae infection.

RESULTS

We report two 6-year-old boys with M. pneumoniae antecedent infection who presented initially with impaired consciousness followed by limb weakness, limb pain and urinary retention, and responded well to immunotherapy.

CONCLUSIONS

We described 2 patients who presented symptomatic combined CNS and PNS involvement with persistent urinary retention associated with M. pneumoniae infection. We found autoimmunity plays an important role and recommend that antibiotics and immunomodulators should be administered with concurrent CNS and PNS involvement associated with M. pneumoniae.

Disease burden and macrolide resistance of Mycoplasma pneumoniae infection in adults in the Asia-Pacific region

OBJECTIVES

In the Asia-Pacific region, Mycoplasma pneumoniae (MP) could be a notable pathogen responsible for adult community-acquired pneumonia (CAP), with varying prevalence rates. This comprehensive review aimed to explore the epidemiology, clinical manifestations, macrolide resistance, and molecular characteristics of MP in adults across several countries in Asia.

METHODS

PubMed, Embase, and Google Scholar were searched for relevant articles from 2010-2023 based on the following keywords: adult and Mycoplasma pneumoniae.

RESULTS

The prevalence of MP in CAP patients in these countries ranged from 2.1% in Korea to 25.5% in Japan. Macrolide resistance was prominent, particularly in China, with rates ranging 26.9-100%. Clinical manifestations of MP infection included protean extrapulmonary manifestations, and complications such as rhabdomyolysis and thrombocytopenia. Molecular characteristics, especially the multiple locus variable-number tandem-repeat analysis type 4/5/7/2, remained predominant across various countries, emphasising the importance of ongoing surveillance.

CONCLUSIONS

This review highlights the urgent need for continued monitoring of MP infections, macrolide resistance, and molecular characteristics to inform effective prevention and treatment strategies in the Asia-Pacific region.

Childhood Mycoplasma pneumoniae: epidemiology and manifestation in Northeast and Inner Mongolia, China

Mycoplasma pneumoniae (MP) is commonly detected in children. However, the epidemiological trends of MP in Northeast (NE) China are unclear. This retrospective study aimed to investigate the prevalence of MP infections in this understudied region. The clinical manifestations and bronchoscopic findings observed in hospitalized patients with severe Mycoplasma pneumoniae pneumonia (SMPP) were collected from comprehensive data obtained from six tertiary hospitals in NE and Inner Mongolian (IM) China, from 1 January 2017 to 31 December 2023. A total of 5,593,530 children who visited the outpatient and emergency departments, and 412,480 inpatient hospitalized children were included in the study. The positivity rate of MP immunoglobulin M (IgM) in the children who visited the outpatient and emergency departments varied from 7.80% to 10.12%, whereas that of MP infection in hospitalized children ranged from 27.18% to 30.10%. Children hospitalized for MP infection were mainly concentrated in the 1- to 4-year (41.39%) and 4- to 7-year (24.25%) age groups. Before 2020, the season with the highest incidence of MP was winter. After the implementation of non-pharmaceutical interventions (NPIs), the MP epidemic season changed, and the number of children with MP infections decreased; however, the proportion of MP infections in hospitalized children did not change significantly. Starting from August 2023, the MP infection rate in outpatient, emergency, and hospitalized children increased sharply, with SMPP and its complications (e.g., plastic bronchitis and pleural effusion) increasing significantly. MP is prevalent in NE and IM, China. When the NPIs ended, MP infection showed a delayed outbreak trend, and the number of children with severe infection increased significantly.

IMPORTANCE

In Northeastern (NE) and Inner Mongolia (IM), the incidence of Mycoplasma pneumoniae (MP) infections, including severe Mycoplasma pneumoniae pneumonia (SMPP), is high, posing health risks and imposing substantial economic burdens on the local population. Therefore, it is imperative to prioritize the study of MP prevalence and address the research gaps in MP epidemiology in these areas of China. We obtained a comprehensive collection of pediatric outpatient, emergency, and inpatient data from six public Grade III hospitals. We believe that our study makes a significant contribution to the literature because understanding regional variations in MP infections can help healthcare professionals tailor prevention and treatment strategies, and studying bronchoscopic manifestations can provide insights into the impact of the disease on the respiratory system, potentially leading to a more effective clinical management.

Recurrent Reactive Infectious Mucocutaneous Eruption in an Adult Male Secondary to Mycoplasma Infection: A Case Report

Mycoplasma pneumoniae commonly causes respiratory tract infections but can also involve the skin and mucosal surfaces. Reactive infectious mucocutaneous eruption (RIME) secondary to mycoplasma infection is uncommon in adults but is an important clinical entity. We present the case of a 26-year-old male who experienced recurrent episodes of erythematous and painful oral ulcers without any prodromal or respiratory symptoms. Serological testing confirmed a recent mycoplasma infection. The patient was successfully treated with oral steroids and supportive therapy. This case underscores the challenges of diagnosing RIME, particularly in the absence of typical respiratory symptoms. Moreover, oral steroid therapy with supportive treatment may suffice to manage RIME if the patient lacks an ongoing infection or other underlying pathologies.

Intracardiac and Cerebral Thrombosis Complicated With Mycoplasma Pneumonia

A seven-year-old girl developed multiposition thrombosis after fever and respiratory symptoms. Chest computed tomography (CT) scan demonstrated bilateral infiltrates, consolidation of the right lower lobe, and pleural effusion in the right lung field. Brain magnetic resonance imaging (MRI) showed multiple abnormal signals in the brain with limited diffusion, and cerebral infarction could not be excluded. Echocardiography revealed hypoechoic mitral valve tips, which are likely to be suspected as vegetation. Mycoplasma pneumoniae infection was clarified by a four-fold increase in IgG antibodies to M. pneumoniae sera. D-dimer levels were elevated increasingly. We found and reported this rare pediatric case of an M. pneumoniae-induced severe pneumonia complicated with intracardiac and cerebral thrombosis. We investigate the clinical characteristics, diagnosis, and treatment of refractory mycoplasma pneumonia complicated with intracardiac and cerebral thrombosis in children.

A comparative study of general and severe mycoplasma pneumoniae pneumonia in children

OBJECTIVES

The increasing prevalence of severe Mycoplasma pneumoniae pneumonia (SMPP) poses a significant threat to the health of children. This study aimed to characterise and assess the outcomes in children with SMPP.

METHODS

We retrospectively analysed children hospitalised for M. pneumoniae pneumonia (MPP) between January and December 2022. Retrospectively, demographic, clinical, underlying diseases, laboratory and radiological findings, and treatment outcomes were collected and analysed. Disease severity was defined as severe or general according to the Guideline for diagnosis and treatment of community-acquired pneumonia in children (2019 version).

RESULTS

Over a 12-month observation period, 417 children with MPP were enrolled, 50.6% (211/417) of whom had SMPP, with the peak incidence observed in winter. Of the 211 children with SMPP, 210 were treated and discharged with improvement, while one child with congenital heart disease died of cardioembolic stroke. A significantly higher proportion of patients with SMPP had underlying diseases, extrapulmonary complications (myocardial and digestive system involvement), and bacterial co-infection. A total of 25 (12%) children with SMPP received mechanical ventilation. The median duration of mechanical ventilation was 3 days. All children were treated with macrolide antibiotic. A significantly higher proportion of patients with SMPP received antibiotic other than macrolides, methylprednisolone sodium succinate, intravenous immunoglobulin and anticoagulation, compared with patients with general MPP (GMPP). Children with SMPP had significantly higher levels of white blood cells, neutrophil percentage, C-reactive protein, procalcitonin, interferon-γ, interleukin (IL)-2, IL-5, IL-6, IL-8, IL-10 and significantly lower percentages of lymphocytes, monocytes, and natural killer cells, compared with GMPP group.

CONCLUSION

Our findings suggest that severely ill children have more pronounced inflammatory reaction and extrapulmonary complications. For effective management of children with SMPP, hormonal, prophylactic, anticoagulant therapy, as well as the use of antibiotics other than macrolides for bacterial co-infections, could be incorporated into treatment regimens.

A new dynamic nomogram for predicting the risk of severe Mycoplasma pneumoniae pneumonia in children

Mycoplasma pneumoniae pneumonia (MPP) is usually mild and self-limiting, but still about 12% of them will progress to severe Mycoplasma pneumoniae pneumonia (SMPP), which have poor survival rates and often require intensive medical resource utilization. We retrospectively collected clinical data from 526 children with MPP admitted to the Children's Hospital Affiliated to Zhengzhou University from June 2018 to February 2023 and randomly divided the data into a training cohort and a validation cohort at a ratio of 4:1. Univariate and multivariate logistic regressions were used to identify independent risk factors for SMPP. Age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze are independent risk factors for SMPP in children. Then, we built an online dynamic nomogram ( https://ertongyiyuanliexiantu.shinyapps.io/SMPP/ ) based on the 11 independent risk factors. The C-index, ROC curve, DCA curve and calibration curve were used to assess the performance of the nomogram, which all showed that the dynamic nomogram has excellent clinical value. Based on age, AGR, NLR, CRP, ESR, MPV, coinfection, pleural effusion, primary disease, fever days ≥ 7 and wheeze, the first dynamic nomogram for accurately predicting SMPP was successfully established.

Wuhu decoction combined with azithromycin for treatment of Mycoplasma pneumoniae pneumonia in Asian children: a systematic review and meta analysis of randomized controlled trials

Objective: This study constitutes a pioneering systematic review and meta analysis delving into the clinical efficacy and safety of the combined therapy involving Wuhu Decoction and azithromycin for treating Mycoplasma pneumoniae pneumonia in pediatric patients. Methods: This study conducted a comprehensive computerized search, covering 6 Chinese databases and 6 English databases, to collect randomized controlled trials related to the combined use of Wuhu Decoction and azithromycin for treating Mycoplasma pneumoniae pneumonia in pediatric patients. The search was extended until August 2023. Two independent researchers were involved in literature screening, data extraction, and bias risk assessment. Meta-analysis was performed using Stata 14.0 and RevMan 5.4 software. Additionally, meta-regression analysis and subgroup analysis were carried out on primary outcomes to identify potential sources of heterogeneity and confounding factors. Results: A total of 22 randomized controlled trials involving 2,026 patients were included in this study. The combined therapy of Wuhu Decoction and azithromycin demonstrated superior efficacy compared to azithromycin alone (RR = 1.17, 95% CI [1.13, 1.21], p < 0.00001; low certainty of evidence). Additionally, patients receiving the combination therapy experienced significantly reduced the disappearance time of fever (MD = -1.42, 95% CI [-1.84, -1.00], p < 0.00001; very low certainty of evidence), disappearance time of cough (MD = -2.08, 95% CI [-2.44, -1.71], p < 0.00001; very low certainty of evidence), disappearance of pulmonary rales (MD = -1.97, 95% CI [-2.31, -1.63], p < 0.00001; very low certainty of evidence), and disappearance time of wheezing (MD = -1.47, 95% CI [-1.72, -1.22], p < 0.00001; very low certainty of evidence). Meta-regression analysis suggested that course of disease, sample size, and age might be sources of heterogeneity. Subgroup and sensitivity analyses reaffirmed the stability of these results. Furthermore, analyses of secondary outcomes such as T lymphocytes, serum inflammatory factors, and the incidence rate of adverse reactions consistently favored the combination therapy of WHD and azithromycin over azithromycin alone, with statistically significant differences. Conclusion: Based on our meta-analysis findings, the combined therapy of Wuhu Decoction and azithromycin for treating pediatric Mycoplasma pneumoniae pneumonia exhibited superior overall efficacy in comparison to azithromycin monotherapy. However, in the included 22 studies, the majority of evaluated factors showed unclear bias risks, and a persistent bias risk was consistently present within one category. Moreover, due to the low quality of evidence, interpreting these results should be approached with caution. Hence, we emphasize the necessity for future high-quality, multicenter, and large-sample clinical randomized controlled trials. These trials are essential to provide more robust data for evidence-based research and to establish higher-quality evidence support. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023465606.

Mycoplasma pneumoniae Outbreak in 2023: Post-pandemic Resurgence of an Atypical Bacterial Pathogen

The syndromic nature of infections caused by pneumonia-causing pathogens including Mycoplasma pneumoniae necessitates detection via multiplex PCR for accurate and timely diagnosis to control the infection spread. In this study, we demonstrate an increase in the detection of M. pneumoniae in the outpatient population, during 2023, as compared to the previous two years (2021-2022). In this aggregated survey, respiratory samples collected within the continental United States were tested for the presence of M. pneumoniae and other respiratory bacterial and viral pathogens using a multiplex PCR assay. Patient data was analyzed on the basis of age, gender and geographical location. The positive detection of M. pneumoniae in 2021 and 2022 was 0.004% and 0.006%, respectively. The positivity rate of M. pneumoniae in 2023 increased to 0.21%. The highest proportion of M. pneumoniae cases were detected from Georgia with the outbreak generally concentrated in large urban settings. Median age of the patients testing positive for M. pneumoniae was 10 (interquartile range [IQR] 8-18) years with an almost equal distribution between male and female patients. Other respiratory, viral and bacterial, pathogens detected in samples positive for M. pneumoniae were similar in proportion to the M. pneumonia-negative population. A survey of the ICD-10 codes submitted in conjunction with the samples suggests that the current outbreak is mostly associated with upper respiratory tract infections. The present study is the first detailed report in the United States that shows an unprecedented increase in the detection of M. pneumoniae in the outpatient population during 2023. Our analysis suggests that this outbreak was not associated with any other bacterial or viral respiratory pathogen. The outbreak of this atypical pathogen was concentrated in the pediatric population in large urban areas. The 2023 outbreak could be a return of the cyclical M. pneumoniae outbreaks witnessed prior to the COVID-19 pandemic. Our study highlights the importance of performing continuous surveillance of respiratory pathogens, especially in the altered epidemiological landscape of the post-COVID world.

Insights into the defensive roles of lncRNAs during Mycoplasma pneumoniae infection

Mycoplasma pneumoniae causes respiratory tract infections, affecting both children and adults, with varying degrees of severity ranging from mild to life-threatening. In recent years, a new class of regulatory RNAs called long non-coding RNAs (lncRNAs) has been discovered to play crucial roles in regulating gene expression in the host. Research on lncRNAs has greatly expanded our understanding of cellular functions involving RNAs, and it has significantly increased the range of functions of lncRNAs. In lung cancer, transcripts associated with lncRNAs have been identified as regulators of airway and lung inflammation in a process involving protein complexes. An excessive immune response and antibacterial immunity are closely linked to the pathogenesis of M. pneumoniae. The relationship between lncRNAs and M. pneumoniae infection largely involves lncRNAs that participate in antibacterial immunity. This comprehensive review aimed to examine the dysregulation of lncRNAs during M. pneumoniae infection, highlighting the latest advancements in our understanding of the biological functions and molecular mechanisms of lncRNAs in the context of M. pneumoniae infection and indicating avenues for investigating lncRNAs-related therapeutic targets.

Human immunoglobulin in combination with antimicrobial agents enhances the treatment efficacy and reduces inflammatory response in children with severe pneumonia

OBJECTIVE

To investigate the efficacy of human immunoglobulin combined with antibiotics in treating severe pediatric pneumonia.

METHODS

A retrospective analysis was performed on 210 pediatric patients with severe pneumonia admitted to the Department of Neonatology of Cangzhou Central Hospital from April 2019 to October 2022. Patients were divided into two groups (the observation group and the control group) based on the administration of human immunoglobulin. Clinical indexes of both groups before and after treatment were analyzed to determine the therapeutic effect of different treatment methods on pediatric severe pneumonia.

RESULTS

The durations of cough, fever, pulmonary rales, and lung shadow, and hospitalization time in the observation group were significantly shorter than those in the control group (all P<0.05). The total clinical effective rate in the observation group was significantly higher than that in the control group (P<0.05). Levels of inflammatory factors (IL-6, IL-8 and hsCRP) were decreased in both groups after treatment (all P<0.05), and were lower in the observation group compared with the control group after treatment (all P<0.05). The serum levels of IgA, IgG and IgM after five days of intervention were obviously higher than those before intervention in the observation group (all P<0.05), but the serum levels of IL-4, INF-γ and INF-γ/IL-4 were obviously lower (all P<0.05). The total incidence of adverse reactions between two groups after intervention was not statistically different (P<0.05).

CONCLUSION

The combination of human immunoglobulin and antibiotics for the treatment of pediatric severe pneumonia is beneficial, because it improves efficacy, boosts the immune system, and reduces inflammation.

Research status and challenges of Mycoplasma pneumoniae pneumonia in children: A bibliometric and visualization analysis from 2011 to 2023

BACKGROUND

Mycoplasma pneumoniae (MP) infections occur in regional outbreaks every 3 to 7 years, lasting up to 2 years. Since this fall, there has been a significant rise in MP infections among children in China, indicating a regional epidemiological trend that imposes an increased national public health burden. To date, bibliometric methods have not been applied to studies on MP infection in children.

METHODS

We searched for all relevant English publications on MP pneumonia in children published from 2011 to 2023 using Web of Science. Analytical software tools such as Citespace and VOSviewer were employed to analyze the collected literature.

RESULTS

993 articles on MP pneumonia in children were published in 338 academic journals by 5062 authors affiliated with 1381 institutions across 75 countries/regions. China led in global productivity with 56.19%. Among the top 10 prolific organizations, 8 were Chinese institutions, with Soochow University being the most active, followed by Capital Medical University and Zhejiang University. Zhimin Chen from Zhejiang University School of Medicine exhibited the highest H-index of 32. Keyword co-occurrence network analysis revealed 7 highly relevant clusters.

CONCLUSION

The current research hotspots and frontiers in this field are primarily MP pneumonia, refractory MP pneumonia, lactate dehydrogenase, asthma, and biomarker. We anticipate that this work will provide novel insights for advancing scientific exploration and the clinical application of MP pneumonia in children.

Observational retrospective clinical study on clinical features of macrolide-resistant Mycoplasma pneumoniae pneumonia in Chinese pediatric cases

This study aimed to investigate differences in clinical characteristics and laboratory findings between children infected with Macrolide-Sensitive Mycoplasma pneumoniae (MSMP) and Macrolide-Resistant Mycoplasma pneumoniae (MRMP). Additionally, the research sought to identify laboratory markers for rapidly distinguishing refractory Mycoplasma pneumoniae pneumonia (RMPP) from ordinary Mycoplasma pneumoniae pneumonia (OMPP). In total, 265 Mycoplasma pneumoniae (MP) patients were included, with MRMP identified by specific point mutations in domain V of the 23S rRNA gene. A retrospective analysis compared the clinical courses and laboratory data, revealing that MRMP patients experienced prolonged febrile days (P = 0.004), elevated CRP levels (P < 0.001), and higher MP DNA loads than MSMP patients (P = 0.037). Based on clinical symptoms, MRMP was divided into RMPP (n = 56) and OMPP (n = 70), with RMPP demonstrating significantly increased IL-18, community-acquired respiratory distress syndrome (CARDS) toxins in nasopharyngeal aspirate, and serum CRP levels (P < 0.001; P = 0.006; P < 0.001). In conclusion, timely recognition of RMPP is crucial for enhancing prognosis. The identification of MRMP, coupled with proinflammatory cytokines such as IL-18, CARDS toxins, and CRP, emerges as promising markers with the potential to contribute significantly to diagnostic accuracy and prognosis assessment.

Efficacy of doxycycline therapy for macrolide-resistant Mycoplasma pneumoniae pneumonia in children at different periods

BACKGROUND

The prevalence of macrolide-resistant Mycoplasma pneumoniae has increased considerably. Treatment in children has become challenging. This study aimed to evaluate the efficacy of doxycycline therapy for macrolide-resistant Mycoplasma pneumoniae pneumonia in children at different periods.

METHODS

We retrospectively analyzed the data of patients with macrolide-resistant Mycoplasma pneumoniae pneumonia hospitalized between May 2019 to August 2022. According to treatment, patients were divided into three groups: oral doxycycline treatment alone (DOX group), changed from intravenous azithromycin to oral doxycycline (ATD group), and intravenous azithromycin treatment alone (AZI group). ATD group cases were separated into two sub-groups: intravenous azithromycin treatment<3 days (ATD1 group) and ≥ 3 days (ATD2 group). Clinical symptoms were compared in each group and adjusted by Propensity score matching (PSM) analysis.

RESULTS

A total of 106 were recruited in this study. 17 (16%) were in DOX group, 58 (55%) in ATD group, and 31(29%) in AZI group. Compared with ATD group and AZI group, the DOX group showed shorter hospitalization duration and fever duration after treatment, while higher rate of chest radiographic improvement. After using PSM analysis, shorter days to hospitalization duration (P = 0.037) and to fever duration after treatment (P = 0.027) in DOX + ATD1 group than in ATD2 group was observed. A higher number of patients in the DOX + ATD1 group achieved defervescence within 72 h (P = 0.031), and fewer children received glucocorticoid adjuvant therapy (P = 0.002). No adverse reactions associated with doxycycline was observed during treatment.

CONCLUSIONS

Children receiving early oral doxycycline had a shorter duration of fever and hospitalization in macrolide-resistant Mycoplasma pneumoniae patients.

Microfluidic systems for infectious disease diagnostics

Microorganisms, encompassing both uni- and multicellular entities, exhibit remarkable diversity as omnipresent life forms in nature. They play a pivotal role by supplying essential components for sustaining biological processes across diverse ecosystems, including higher host organisms. The complex interactions within the human gut microbiota are crucial for metabolic functions, immune responses, and biochemical signalling, particularly through the gut-brain axis. Viruses also play important roles in biological processes, for example by increasing genetic diversity through horizontal gene transfer when replicating inside living cells. On the other hand, infection of the human body by microbiological agents may lead to severe physiological disorders and diseases. Infectious diseases pose a significant burden on global healthcare systems, characterized by substantial variations in the epidemiological landscape. Fast spreading antibiotic resistance or uncontrolled outbreaks of communicable diseases are major challenges at present. Furthermore, delivering field-proven point-of-care diagnostic tools to the most severely affected populations in low-resource settings is particularly important and challenging. New paradigms and technological approaches enabling rapid and informed disease management need to be implemented. In this respect, infectious disease diagnostics taking advantage of microfluidic systems combined with integrated biosensor-based pathogen detection offers a host of innovative and promising solutions. In this review, we aim to outline recent activities and progress in the development of microfluidic diagnostic tools. Our literature research mainly covers the last 5 years. We will follow a classification scheme based on the human body systems primarily involved at the clinical level or on specific pathogen transmission modes. Important diseases, such as tuberculosis and malaria, will be addressed more extensively.

In vitro and in vivo study of andrographolide nanoparticles for the treatment of Mycoplasma pneumoniae pneumonia

OBJECTIVE(S)

The emergence of antibiotic resistance has led to suboptimal treatment outcomes for Mycoplasma pneumoniae pneumonia (MPP). Exploring naturally occurring drug components that are both effective against MPP and non-toxic may be a promising choice. This study aimed to investigate the therapeutic effect of andrographolide nanoparticles on pneumonia caused by Mycoplasma pneumoniae infection.

METHODS

Andrographolide alginate-poloxamer nanoparticles (AND-ALG-POL/NPs) were obtained by wet medium grinding, and the characterization and in vitro release of the prepared andrographolide nanoparticles were examined by high performance liquid chromatography, particle size analyzer, zeta potential meter and transmission electron microscopy. The cytotoxicity and anti-inflammatory effects of AND-ALG-POL/NPs were evaluated in vitro by MP-infected lung epithelial cells BEAS-2B. Symptoms of pneumonia, total cell count, total protein content and inflammatory factor levels in BALF were assessed by MP-induced pneumonia in BALB/c mice treated with AND-ALG-POL/NPs, and histopathological studies were performed on lung tissues from experimental animals.

RESULTS

The results showed that the prepared AND-ALG-POL/NPs were homogeneous spherical with a diameter of 180 ± 23 nm, a zeta potential of (-14.4 ± 2.1) mV, an average encapsulation rate of 87.74 ± 0.87 %, and an average drug loading of 13.17 ± 0.54 %. AND-ALG-POL/NPs were capable of slow release in vitro and showed significant inhibitory ability against MP (P < 0.001). However, AND-ALG-POL/NPs were not cytotoxic to normal cells and alleviated MP infection-induced apoptosis and elevated inflammatory factors. In the in vivo experiments, AND-ALG-POL/NPs alleviated the symptoms of pneumonia in MPP mice, reduced the abnormally elevated total cell count, total protein content and inflammatory factor levels in BALF, and alleviated lung tissue edema, inflammatory cell infiltration and apoptosis (P < 0.001). Meanwhile, the therapeutic effects of AND-ALG-POL/NPs on MPP were similar to those of azithromycin (AZM) and higher than those of andrographolide (AND) free monotherapy (P < 0.001).

CONCLUSION

In summary, the prepared AND-ALG-POL/NPs can effectively inhibit MPP in vitro and in vivo, and the effect is similar to that of AZM. Therefore, AND- ALG - POL/NPs have the potential to replace AZM as a potential drug for the treatment of MPP.

Clinical significance of measuring MP-DNA, C-reactive protein, and inflammatory cytokines in children with mycoplasma pneumoniae pneumonia

OBJECTIVE

To explore the clinical significance of detecting mycoplasma pneumoniae (MP)-DNA, C-reactive protein (CRP), interleukin-6 (IL-6), IL-8, and IL-10 in children with mycoplasma pneumoniae pneumonia (MPP).

METHODS

The data from 106 children who received treatment or underwent health examination in the Children's Medical Center of Anhui Medical University from January 2021 to October 2022 were collected and analyzed retrospectively. The observation group (OG) consisted of 64 children with MPP, while the control group (CG) consisted of 42 healthy children. The levels of IL-6, IL-8, IL-10, CRP, and MP-DNA were compared between the two groups. The diagnostic value of MP-DNA in patients with MPP and its correlation with the levels of IL-6, IL-8, IL-10 and CRP were analyzed.

RESULTS

The level of MP-DNA in the OG was notably higher than that in the CG (P<0.05). Additionally, the levels of IL-6, IL-8, IL-10, and CRP in the OG were significantly higher than those in the CG (P<0.05). MP-DNA was positively correlated with the levels of IL-6, IL-8, IL-10, and CRP (P<0.05). The area under the curve of MP-DNA in diagnosing MPP was 0.979, with a specificity of 92.19% and a sensitivity of 97.62%.

CONCLUSION

Indicators such as MP-DAN, IL-6, IL-8 are crucial in the development and progression of MPP, playing an important role in diagnosing and treating patients with MPP.

Clinical Characteristics of Lung Consolidation with Mycoplasma pneumoniae Pneumonia and Risk Factors for Mycoplasma pneumoniae Necrotizing Pneumonia in Children

INTRODUCTION

Mycoplasma pneumoniae necrotizing pneumonia (MPNP) is an uncommon but increasingly recognized severe complication of pneumonia, and the delayed diagnosis and treatment are prone to pulmonary sequelae. The aim of this study is to explore independent risk factors for MPNP in children with lung consolidation.

METHODS

A retrospective observational study was conducted on 118 children with MPNP (MPNP group) and 184 children with lung consolidation of Mycoplasma pneumoniae pneumonia (MPP) (control group) admitted to Children's Hospital Affiliated to Zhengzhou University from June 2018 to August 2023. Clinical manifestations and laboratory data were analyzed and the independent risk factors for MPNP in children were analyzed by multivariate logistic regression.

RESULTS

The age of onset, hospitalization days, fever days, proportion of dyspnea, chest pain, complications, and need for fiberoptic bronchoscopic alveolar lavage (FBAL) were higher than those in the control group, and the difference was statistically significant (P < 0.05). The levels of white blood cells (WBC), platelets, neutrophil percentage (N%), neutrophil-to-lymphocyte ratio (NLR), C-reactive protein (CRP), fibrinogen (Fbg), D-dimer (D-D), erythrocyte sedimentation rate (ESR), alanine transaminase (ALT), γ-glutamyl transpeptidase (γ-GGT), globulin, lactate dehydrogenase (LDH), α-hydroxybutyrate dehydrogenase (α-HBDH), urea, immunoglobulin G (IgG), immunoglobulin M (IgM), immunoglobulin A (IgA), complement component 3, antistreptolysin O (ASO), serum ferritin, and interleukin-6 (IL-6) in the MPNP group were higher than those in the control group. Red blood cell (RBC), lymphocyte percentage (L%), activated partial thromboplastin time (APTT), alkaline phosphatase (ALP), total protein, albumin, albumin-to-globulin ratio (AGR), creatine kinase (CK), uric acid, natrium, chlorine, calcium, and complement C4 in the MPNP group were lower than those in the control group, and the difference was statistically significant (P < 0.05). The results of multivariate logistic regression analysis showed that age ≥ 83.50 months, fever days ≥ 10.50, ALT ≥ 15.25 U/l, IgM ≥ 1.46 g/l, complement C3 ≥ 1.47 g/l, Fbg ≥ 3.93 g/l, dyspnea and needing FBAL were independent risk factors for MPNP in children.

CONCLUSIONS

Age, fever days, ALT, IgM, complement C3, Fbg, dyspnea, and needing FBAL were independent risk factors for MPNP in children. For children suspected of MPNP, pediatricians should pay close attention to the above indicators, strive for early diagnosis and treatment, and improve prognosis.

Development and evaluation of a multiplex digital PCR method for sensitive and accurate detection of respiratory pathogens in children

The emergence of multiplex digital polymerase chain reaction (dPCR) and other detection technologies for respiratory pathogens in recent years has facilitated greater understanding of respiratory virus epidemics. In this study, a multiplex dPCR method was developed and evaluated as a means of detecting five respiratory pathogens in children with acute lower respiratory tract infection (ALRTI). With 139 nasopharyngeal swabs collected from children with ALRTI, pathogens were detected using dPCR and quantitative real-time PCR (qPCR) methods. Of those specimens, dPCR detected 86 positive cases, while qPCR identified 84. Moreover, dPCR exhibited higher sensitivity than qPCR, and displayed no cross-reactivity with common respiratory pathogens. These findings suggest that dPCR-based method could become one of the most promising options for acute respiratory pathogen detection.

Efficacy and Influencing Factors of Sangju Cough Mixture in the Adjuvant Treatment of Adult Patients with Mycoplasma pneumoniae Infection: A Retrospective Study

Purpose

Sangju-Yin, supplemented with some drugs, has frequently demonstrated therapeutic efficacy against colds, albeit its effect on Mycoplasma pneumoniae (MP) infection remains unknown. Therefore, we aimed to elucidate the treatment efficacy and influencing factors of a Sangju cough mixture on MP infection in adults.

Patients and Methods

Between January 2021 and December 2022, 150 adult patients with MP infection at the Lishui Hospital of Traditional Chinese Medicine Affiliated with Zhejiang University of Traditional Chinese Medicine were assigned to the treatment (administered Sangju cough mixture and moxifloxacin tablets) or the control (administered moxifloxacin tablets) groups.

Results

When compared with the control group, the treatment group exhibited significantly improved traditional Chinese medicine syndrome scores, increased CD4+ T cell levels, and decreased CD8+ T cell levels (all P < 0.05). After 7 days of treatment, the negative conversion rate of the MP-specific immunoglobulin M (MP-IgM) antibody of the treatment group was not significantly different from that of the control group (P > 0.05); however, after 14 days of treatment, the rate was significantly higher in the treatment group (P < 0.05). The univariate regression analysis revealed that combined chronic respiratory disease, failure to take Sangju cough mixture, combined pneumonia, Nutritional Risk Screening 2002 (NRS 2002) score of at least 3 points, and age were associated with the negative conversion of the MP-IgM antibody (all P < 0.05). Nevertheless, the multivariate regression model revealed that the NRS 2002 score of at least 3 points was not an independent risk factor (P > 0.05).

Conclusion

Sangju cough mixture can improve symptoms, accelerate the negative conversion time of MP-IgM antibody, and promote rehabilitation of the patients.

Molecular epidemiology of Mycoplasma pneumoniae pneumonia in children, Wuhan, 2020-2022

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of community-acquired pneumonia in children. The factors contributing to the severity of illness caused by M. pneumoniae infection are still under investigation. We aimed to evaluate the sensitivity of common M. pneumoniae detection methods, as well as to analyze the clinical manifestations, genotypes, macrolide resistance, respiratory microenvironment, and their relationship with the severity of illness in children with M. pneumoniae pneumonia in Wuhan.

RESULTS

Among 1,259 clinical samples, 461 samples were positive for M. pneumoniae via quantitative polymerase chain reaction (qPCR). Furthermore, we found that while serological testing is not highly sensitive in detecting M. pneumoniae infection, but it may serve as an indicator for predicting severe cases. We successfully identified the adhesin P1 (P1) genotypes of 127 samples based on metagenomic and Sanger sequencing, with P1-type 1 (113/127, 88.98%) being the dominant genotype. No significant difference in pathogenicity was observed among different genotypes. The macrolide resistance rate of M. pneumoniae isolates was 96% (48/50) and all mutations were A2063G in domain V of 23S rRNA gene. There was no significant difference between the upper respiratory microbiome of patients with mild and severe symptoms.

CONCLUSIONS

During the period of this study, the main circulating M. pneumoniae was P1-type 1, with a resistance rate of 96%. Key findings include the efficacy of qPCR in detecting M. pneumoniae, the potential of IgM titers exceeding 1:160 as indicators for illness severity, and the lack of a direct correlation between disease severity and genotypic characteristics or respiratory microenvironment. This study is the first to characterize the epidemic and genomic features of M. pneumoniae in Wuhan after the COVID-19 outbreak in 2020, which provides a scientific data basis for monitoring and infection prevention and control of M. pneumoniae in the post-pandemic era.

Clinical Features and Biomarkers for Early Prediction of Refractory Mycoplasma Pneumoniae Pneumonia in Children

Objective

The study aimed to analyze the clinical characteristics of children with RMPP and to explore the biomarkers for the early prediction of RMPP, thus providing references for the clinical diagnosis and treatment of RMPP in children.

Methods

Baseline clinical characteristics, clinical symptoms, physical examination, chest imaging, and laboratory indicators between children with RMPP and general refractory mycoplasma pneumoniae pneumonia (GMPP) were compared. Multiple logistic regression analysis was used to determine independent risk factors for RMPP. ROC curves were adopted to analyze the predictive values of biomarkers.

Results

The RMPP group had more severe clinical symptoms and manifestations on imaging (including pleural effusion, pulmonary consolidation, and pulmonary atelectasis), a higher incidence of extrapulmonary complications, and a longer duration of hospital stays. Results of multiple logistic regression analysis showed that serum D-dimer (OR = 8.169, P < 0.001), C-reactive protein (CRP) (OR = 1.146, P < 0.001), and lactate dehydrogenase (LDH) (OR = 1.025, P < 0.001) levels were independent risk factors for RMPP. The area under the receiver operating characteristic curve (AUROC) in RMPP prediction was 0.841, 0.870, and 0.893 for serum levels of D-dimer, CRP, and LDH, respectively (P < 0.001), with a cutoff value of 1.47 ng/ml, 39.34 mg/L, and 379 IU/L, respectively.

Conclusions

Serum D-dimer, CRP, and LDH levels were related to the severity of mycoplasma pneumoniae pneumonia in children and had potential as biomarkers for the early prediction of RMPP, suggesting great applicative values for the early diagnosis and timely intervention of children with RMPP in clinical practice.

Mycoplasma pneumoniae epidemic in Denmark, October to December, 2023

We report a surge of patients, especially children and adolescents, with respiratory disease caused by Mycoplasma pneumoniae in Denmark since October 2023. While the surge has reached an epidemic level, no impact on hospital capacity has been observed; only 14% (446/3,195) of cases, primarily adults, required hospitalisation. Macrolide resistance was detected in less than 2% of samples tested. Timely monitoring of hospitalisations linked to M. pneumoniae infections has been established to inform the healthcare system, decisionmakers and the public.

Chest imaging classification in Mycoplasma pneumoniae pneumonia is associated with its clinical features and outcomes

BACKGROUND

The imaging findings of Mycoplasma pneumoniae pneumonia (MPP) vary; however, few studies have focused on the relationship of imaging classification with clinical manifestations and outcomes.

OBJECTIVE

To prospectively investigate whether chest imaging classification in Mycoplasma pneumoniae pneumonia (MPP) is associated with its clinical features and outcomes.

METHODS

A total of 1,401 hospitalized children with MPP were enrolled from January 2019 to December 2021. Imaging findings were categorized as bronchopneumonia and consolidation/atelectasis according to X-ray, and bronchopneumonia, consolidation/atelectasis, bronchiolitis, and mosaic pattern according to computed tomography (CT). Clinical characteristics and outcomes of patients with different imaging classifications were prospectively analyzed based on electronic medical records.

RESULTS

Bronchopneumonia was the most common finding (59.6%), while consolidation/atelectasis was the most severe group. Clinical manifestations and laboratory indicators for the consolidation/atelectasis group included serious abnormalities. Further, outcomes of the patients were worse, including having longer total durations of fever and hospitalization, greater hospitalization expenses, and a higher likelihood of developing refractory MPP, necrotizing pneumonia, and bronchiolitis obliterans (BO) in this group. The incidence of bronchiolitis, a disease characterized by a high prevalence of fever, moist rales, and an atopic constitution, tended to increase after the coronavirus disease pandemic and predisposed patients to BO. A mosaic pattern occurred in allergic and young individuals, with wheezing as the main manifestation, with patients having relatively mild symptoms and good outcomes.

CONCLUSION

Different imaging classifications have different clinical features and clinical outcomes; thus, formulating an imaging-based classification system is of great clinical value.

Clinical significance of serum microRNA-146a and inflammatory factors in children with Mycoplasma pneumoniae pneumonia after azithromycin treatment

OBJECTIVE

This study aimed to investigate the clinical significance of serum microRNA-146a and pro-inflammatory factors in children with Mycoplasma pneumoniae pneumonia after azithromycin treatment. microRNA-146a is known to regulate inflammatory responses, and excessive inflammation is a primary characteristic of MPP.

METHODS

Children with MPP received conventional symptomatic therapy along with intravenous administration of azithromycin for one week. Serum levels of microRNA-146a and pro-inflammatory factors were measured using RT-qPCR and ELISA kits, respectively. The correlation between microRNA-146a and pro-inflammatory factors was analyzed by the Pearson method. Pulmonary function indexes were assessed using a pulmonary function analyzer, and their correlation with microRNA-146a and pro-inflammatory factors after treatment was evaluated. Children with MPP were divided into effective and ineffective treatment groups, and the clinical significance of microRNA-146a and pro-inflammatory factors was evaluated using receiver operating characteristic curves and logistic multivariate regression analysis.

RESULTS

Serum microRNA-146a was downregulated in children with MPP but upregulated after azithromycin treatment, contrasting with the trend observed for pro-inflammatory factors. MicroRNA-146a showed a negative correlation with pro-inflammatory cytokines. Pulmonary function parameters were initially reduced in children with MPP, but increased after treatment, showing positive/inverse associations with microRNA-146a and pro-inflammatory factors. Higher microRNA-146a and lower pro-inflammatory factors predicted better efficacy of azithromycin treatment. MicroRNA-146a, tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), and forced expiratory volume in the first second/forced vital capacity (FEV1/FVC) were identified as independent factors influencing treatment efficacy.

CONCLUSION

Azithromycin treatment in children with MPP upregulates microRNA-146a, downregulates pro-inflammatory factors, and effectively improves pulmonary function.

A Novel Detection Procedure for Mutations in the 23S rRNA Gene of Macrolide-Resistant Mycoplasma pneumoniae with Two Non-Overlapping Probes Amplification Assay

Mycoplasma pneumoniae is a significant cause of community-acquired pneumonia, which is often empirically treated with macrolides (MLs), but, presently, resistance to MLs has been a matter of close clinical concern. This assay is intended to contribute to resistance detection of M. pneumoniae in clinical practice. A novel real-time PCR assay with two non-overlapping probes on the same nucleic acid strand was designed in this study. It could effectively detect all mutation types of M. pneumoniae in 23S rRNA at loci 2063 and 2064. The results were determined by the following methods: ΔCT < 0.5 for MLs-sensitive M. pneumoniae; ΔCT > 2.0 for MLs-resistant M. pneumoniae; 10 copies as a limit of detection for all types. For detection of M. pneumoniae in 92 clinical specimens, the consistency between the results of this assay and the frequently used real-time PCR results was 95.65%. The consistency of MLs resistance results between PCR sequencing and this assay was 100% in all 43 specimens. The assay could not only cover a comprehensive range of targets and have high detection sensitivity but is also directly used for detection and MLs analysis of M. pneumoniae in specimens.

Neutrophil-to-lymphocyte ratio as a predictor of poor outcomes of Mycoplasma pneumoniae pneumonia

Introduction

Mycoplasma pneumoniae pneumonia (MPP) may lead to various significant outcomes, such as necrotizing pneumonia(NP) and refractory MPP (RMPP). We investigated the potential of the peripheral blood neutrophil-to-lymphocyte ratio (NLR) to predict outcomes in patients with MPP.

Methods and materials

This was a prospective study of patients with MPP who were admitted to our hospital from 2019 to 2021. Demographic and clinical data were collected from patient records and associated with the development of NP and RMPP and other outcome measures.

Results

Of the 1,401 patients with MPP included in the study, 30 (2.1%) developed NP. The NLR was an independent predictor of NP (odds ratio 1.153, 95% confidence interval 1.022-1.300, P=0.021). The probability of NP was greater in patients with a high NLR (≥1.9) than in those with a low NLR (<1.9) (P<0.001). The NLR was also an independent predictor of RMPP (odds ratio 1.246, 95% confidence interval 1.102-1.408, P<0.005). Patients with a high NLR were more likely to develop NP and RMPP and require intensive care, and had longer total fever duration, longer hospital stays, and higher hospitalization expenses than those with a low NLR (all P<0.005).

Discussion

The NLR can serve as a predictor of poor prognosis in patients with MPP. It can predict the occurrence of NP, RMPP, and other poor outcomes. The use of this indicator would allow the simple and rapid prediction of prognosis in the early stages of MPP, enabling the implementation of appropriate treatment strategies.

In vitro pharmacodynamics of nemonoxacin and other antimicrobial agents against Mycoplasma pneumoniae

IMPORTANCE

This study first reported the in vitro effector kinetics of the new non-fluorinated quinolone, nemonoxacin, against macrolide-resistant M. pneumoniae (MRMP) and macrolide susceptible M. pneumoniae (MSMP) strains along with other antimicrobial agents. The time-kill assays and pharmacodynamic analysis showed that nemonoxacin has significant mycoplasmacidal activity against MRMP and MSMP. This study paves the road to establish appropriate dosing protocols of a new antimicrobial drug for children infected with M. pneumoniae.

Global research trends of Mycoplasma pneumoniae pneumonia in children: a bibliometric analysis

BACKGROUND

Mycoplasma pneumoniae pneumonia (MPP), attributable to Mycoplasma pneumoniae (MP), represents a predominant form of community-acquired pneumonia in pediatric populations, thereby posing a significant threat to pediatric health. Given the burgeoning volume of research literature associated with pediatric MPP in recent years, it becomes imperative to undertake a bibliometric analysis aimed at delineating the current research landscape and emerging trends, thereby furnishing a framework for subsequent investigations.

METHODS

A comprehensive literature search targeting pediatric MPP was conducted in the Web of Science Core Collection. After the removal of duplicate entries through Endnote software, the remaining articles were subject to scientometric analysis via Citespace software, VOSviewer software and R language, focusing on variables such as publication volume, contributing nations, institutions and authors, references and keywords.

RESULTS

A total of 1,729 articles pertinent to pediatric MPP were included in the analysis. China and the United States emerged as the nations with the highest publication output. Italian scholar Susanna Esposito and Japanese scholar Kazunobu Ouchi were the most influential authors in the domain of pediatric MPP. Highly-cited articles primarily focused on the epidemiological investigation of pediatric MPP, the clinical characteristics and treatment of macrolide-resistant MPP, and biomarkers for refractory Mycoplasma pneumoniae pneumonia (RMPP). From the corpus of 1,729 articles, 636 keywords were extracted and categorized into ten clusters: Cluster #0 centered on molecular-level typing of macrolide-resistant strains; Cluster #1 focused on lower respiratory tract co-infections; Clusters #2 and #6 emphasized other respiratory ailments caused by MP; Cluster #3 involved biomarkers and treatment of RMPP; Clusters #4 and #9 pertained to extrapulmonary complications of MPP, Clusters #5 and #7 addressed etiological diagnosis of MPP, and Cluster #8 explored pathogenic mechanisms.

CONCLUSIONS

The past few years have witnessed extensive attention directed towards pediatric MPP. Research in pediatric MPP principally revolves around diagnostic techniques for MP, macrolide resistance, complications of MPP, treatment and diagnosis of RMPP, and elucidation of pathogenic mechanisms. The present study provides pediatric clinicians and researchers with the research status and focal points in this field, thereby guiding the orientation of future research endeavors.

Clinical features and risk factors of plastic bronchitis caused by Mycoplasma pneumoniae pneumonia in children

BACKGROUND

We analyzed the clinical characteristics of children with plastic bronchitis (PB) caused by Mycoplasma pneumoniae (MP) and explored its risk factors.

METHODS

We prospectively analyzed clinical data of children with MP pneumonia (MPP) treated with fiberoptic bronchoscopy (FB). Patients were classified into a PB and non-PB group. General information, clinical manifestations, laboratory tests, results of computed tomography scan, and FB findings were compared between groups. We conducted statistical analysis of risk factors for developing PB.

RESULTS

Of 1169 children who had MPP and were treated with FB, 133 and 1036 were in the PB and non-PB groups, respectively. There were no significant differences in sex, age, and incident season between groups (P > 0.05). The number of children in the PB group decreased during the COVID-19 pandemic. Compared with children in the non-PB group, those in the PB group had longer duration of hospitalization, increased levels of neutrophil (N), C-reactive protein (CRP), procalcitonin (PCT), D-dimer, lactate dehydrogenase (LDH), alanine transaminase (ALT) and aspartate transaminase (AST); lower levels of lymphocyte (L) and platelet (PLT); and higher incidence of lack of appetite, decreased breath sounds, single lobar infiltrate, pleural effusion, pericardial effusion, mucosal erosion and/or necrosis, and bronchial embolization. L levels and pleural effusion were identified as risk factors in multivariate logistic regression.

CONCLUSIONS

Children with PB caused by MPP had a strong and local inflammatory response. L levels and pleural effusion were independent risk factors of PB with MPP in children. Our findings will help clinicians identify potential PB in pediatric patients for early and effective intervention.

Characteristics of the Mycoplasma pneumoniae Epidemic from 2019 to 2020 in Korea: Macrolide Resistance and Co-Infection Trends

Mycoplasma pneumoniae, a major etiological agent of community-acquired pneumonia, exhibits distinct cyclic epidemic patterns recurring every three to five years. Several cases of co-infection with severe acute respiratory syndrome coronavirus 2 have been reported globally, resulting in unfavorable clinical manifestations. This study investigated the epidemiological features of the recent M. pneumoniae outbreak (May 2019-April 2020) using retrospective data from the last five years. Molecular test data for macrolide resistance and co-infection were obtained from the Seegene Medical Foundation. National medical expenditure and hospitalization rates were analyzed using data from The Health Insurance Review and Assessment Service of Korea. The macrolide resistance rate was 69.67%, peaking at 71.30% during the epidemic period, which was considerably higher than the 60.89% rate during non-epidemic periods. The co-infection rate with other respiratory pathogens was 88.49%; macrolide-resistant M. pneumoniae strains showed a 2.33% higher co-infection rate than the susceptible strains. The epidemic period had 15.43% higher hospitalization and 78.27% higher medical budget expenditure per patient than non-epidemic periods. The increased rates of macrolide resistance and co-infection observed in macrolide-resistant M. pneumoniae during the epidemic period highlight the importance of monitoring future outbreaks, especially considering macrolide resistance and the risk of co-infection with other pathogens.

Message in a bubble: the translational potential of extracellular vesicles

Extracellular vesicles (EVs) are small, membrane-enclosed vesicles released by cells into the extracellular milieu. They are found in all body fluids and contain a variety of functional cargo including DNA, RNA, proteins, glycoproteins and lipids, able to provoke phenotypic responses in cells, both locally and at distant sites. They are implicated in a wide array of physiological and pathological processes and hence have attracted considerable attention in recent years as potential therapeutic targets, drug delivery vehicles and biomarkers of disease. In this review we summarise the major functions of EVs in health and disease and discuss their translational potential, highlighting opportunities of - and challenges to - capitalising on our rapidly increasing understanding of EV biology for patient benefit.

Mycoplasma pneumoniae: Among the smallest bacterial pathogens with great clinical significance in children

BACKGROUND

Mycoplasmas are the smallest prokaryotic microorganisms found in nature. Mycoplasma pneumoniae (M. pneumoniae) is the most commonly studied among human mycoplasmas.

OBJECTIVES

In this review, we briefly focus on the recent developments that have enhanced our understanding of M. pneumoniae, one of the smallest pathogenic bacteria of great clinical importance in children.

CONTENT

M. pneumoniae infections may involve either upper or lower respiratory tract or both of them. Extrapulmonary manifestations have been reported in almost every organ, including the skin and the hematologic, cardiovascular, musculoskeletal, and nervous system due to direct local effects, after dissemination of bacteria or indirect effects. The correct identification of M. pneumoniae infections is vital for prescription of the appropriate therapy.There are scarce specific findings of clinical laboratory results for the diagnosis of M. pneumoniae infection. Detection of M. pneumoniae infections can be achieved using culture, serology, or molecular-based methods. Culture is time-consuming, laborious, and expensive. The major types of serological tests for M. pneumoniae include the microtiter plate enzyme immunoassay (EIA), the membrane EIA, indirect immunofluorescence, and particle agglutination. Nucleic acid amplification tests (NAATs) include traditional PCR, nested PCR, real-time quantitative PCR, nucleic acid sequence-based amplification (NASBA), loop-mediated isothermal amplification (LAMP) technology, and RNA simultaneous amplification and testing (SAT). Macrolides have been the drug of choice for treating M. pneumoniae infection in past years. Clinically significant acquired macrolide-resistant M. pneumoniae (MRMP)has emerged worldwide which may be associated with more extrapulmonary complications, and severe clinical and radiological features. Since molecular-based assays can detect M. pnueumoniae in clinical specimens, there is a need for real point of care testing for fast detection of M. pneumoniae or its DNA and mutations in macrolide resistance gene. It is necessary to develop safe vaccines that provide protective immunity against M.pneumoniae infection.

Influence of COVID-19 pandemic on the epidemiology of Mycoplasma pneumoniae infections among hospitalized children in Henan, China

Background

Increasing reports have indicated that non-pharmaceutical interventions to control the COVID-19 pandemic may also have an effect on the prevalence of other pathogens. Mycoplasma pneumoniae is an important atypical pathogen prevalent in children with high rates of macrolide resistance. The aim of this study was to investigate the epidemiological characteristics of M. pneumoniae infection in children before and during the COVID-19 pandemic.

Methods

In this study, M. pneumoniae detection results were extracted from Henan Children's Hospital from 2018 to 2021. The epidemiological characteristics of pediatric M. pneumoniae infection were analyzed.

Results

We found that the highest positive rate of M. pneumoniae infection was 11.00 % in 2018, 14.01 % in 2019, followed by 11.24 % in 2021 and 8.75 % in 2020 (p < 0.001). Most tested children had respiratory system manifestations, and pneumoniae was the most common diagnosis (53.23 %). An increase in the number of positive cases was observed with an increase in age, with a higher number of cases among children over 6 years old. No positive cases were identified among children aged 1-28 days. The decrease in the positive rate among children aged between1-6 years old in 2020 and 2021 was found to be statistically significant (p < 0.001). The pre-pandemic period demonstrated a higher incidence rate in the fall, whereas the summers and winters exhibited a significantly higher positive rate during the pandemic period (p < 0.001). Different regions in Henan also showed different epidemic patterns.

Conclusions

In summary, strict pandemic measures influenced the spread of M. pneumoniae to some extent and changed demographic characteristics, including age, season and regional distribution. Continuous monitoring is required for the control and prevention of related diseases.

Coronary artery dilation in children with febrile illnesses other than Kawasaki disease: A case report and literature review

Background

Coronary artery dilation (CAD) had rarely been described as a cardiac complication of febrile disease other than Kawasaki disease (KD). There are rare cases complicated by CAD reported in patients with Mycoplasma pneumoniae (MP) infection.

Case presentation

A 6-year-old boy with severe Mycoplasma pneumoniae pneumonia (MPP) was transferred to our hospital due to significant respiratory distress on the 11th day from disease onset. Nadroparin, levofloxacin, and methylprednisolone followed by oral prednisone were aggressively prescribed. His clinical condition gradually achieved remission, and the drugs were withdrawn on the 27th day. Regrettably, the recurrent fever attacked him again in the absence of infection-toxic manifestations. Necrotizing pneumonia (NP) was found on chest CT. And echocardiography revealed right CAD (diameter, 3.40mm; z-score, 3.8), however, his clinical and laboratory findings did not meet the diagnostic criteria of KD. CAD was proposed to result from MP infection, and aspirin was prescribed. Encouragingly, the CAD regressed one week later (diameter, 2.50mm; z-score, 1.4). Additionally, the child defervesced seven days after the initiation of prednisone and Nadroparin treatment. The patient was ultimately discharged home on the 50th day. During follow-up, the child was uneventful with normal echocardiography and fully resolved chest CT lung lesions.

Conclusions

CAD can develop in patients with severe MP infection. Pediatricians should be alert to the possibility of CAD in patients with severe MP infection and recognize that CAD might also develop in febrile disease rather than KD.