Mycoplasma pneumoniae pneumonia in children

Cytokines and refractory mycoplasma pneumoniae pneumonia in children: a systematic review

INTRODUCTION

The relationship between cytokines and refractory mycoplasma pneumoniae pneumonia (RMPP) in children was conflicting. The aim of the current study was to perform a systematic review to determine the relationship between cytokines and RMPP in children.

EVIDENCE ACQUISITION

We searched PubMed, and the search was done on 21 November 2022. This search was limited to human studies, with language restriction of English. Studies were included if they reported the relationship between cytokines and RMPP.

EVIDENCE SYNTHESIS

A total of 22 relevant full articles were included in the review. TNF-α levels in the bronchoalveolar lavage fluid (BALF) and IL-18 levels in the blood samples were likely to be associated with RMPP. IL-2 and IL-4 lost significance regardless in the BALF or blood samples. Additionally, there was no significant difference in IFN-γ levels between RMPP patients and non-refractory mycoplasma pneumoniae pneumonia (NRMPP) patients in the BALF. Patients receiving different treatments had different levels of cytokines.

CONCLUSIONS

This analysis offers evidence linking abnormalities of cytokines with RMPP in children, which may be essential for identifying individuals with RMPP. Large prospective studies are needed for further clarification of roles of cytokines in RMPP.

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.

The molecular characteristics, diagnosis, and treatment of macrolide-resistant Mycoplasma pneumoniae in children

The purpose of this study is to review the molecular characteristics, the diagnosis, and treatment of the widespread infection of macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae; MRMP) in children, thus providing a better knowledge of this infection and presenting the associated problems. Single point mutations in the V region of the 23S rRNA gene of M. pneumoniae genome are associated with macrolide resistance. P1-1, MLVA4-5-7-2, and ST3 are usually the predominated genetic types in the M. pneumoniae epidemics. The short-term two times serological IgM (or together with IgG) test in the acute stage can be used for confirmation. Combined serological testing and PCR might be a more prudent method to reduce macrolide consumption and antibiotic selective pressure in a clinical setting. Molecular methods for the detection of single-nucleotide mutations in the V region of the 23S rRNA gene can be used for the diagnosis of MRMP. The routine use of macrolide for the treatment of macrolide-sensitive Mycoplasma pneumoniae (MSMP) infections can get good effect, but the effects are limited for severe MRMP infections. Additional corticosteroids may be required for the treatment of severe MRMP infections in children in China during the era of MRMP.

Global Coinfections with Bacteria, Fungi, and Respiratory Viruses in Children with SARS-CoV-2: A Systematic Review and Meta-Analysis

Background: Coinfection with bacteria, fungi, and respiratory viruses has been described as a factor associated with more severe clinical outcomes in children with COVID-19. Such coinfections in children with COVID-19 have been reported to increase morbidity and mortality. Objectives: To identify the type and proportion of coinfections with SARS-CoV-2 and bacteria, fungi, and/or respiratory viruses, and investigate the severity of COVID-19 in children. Methods: For this systematic review and meta-analysis, we searched ProQuest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus, and Nature through the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for studies on the incidence of COVID-19 in children with bacterial, fungal, and/or respiratory coinfections, published from 1 December 2019 to 1 October 2022, with English language restriction. Results: Of the 169 papers that were identified, 130 articles were included in the systematic review (57 cohort, 52 case report, and 21 case series studies) and 34 articles (23 cohort, eight case series, and three case report studies) were included in the meta-analysis. Of the 17,588 COVID-19 children who were tested for co-pathogens, bacterial, fungal, and/or respiratory viral coinfections were reported (n = 1633, 9.3%). The median patient age ranged from 1.4 months to 144 months across studies. There was an increased male predominance in pediatric COVID-19 patients diagnosed with bacterial, fungal, and/or viral coinfections in most of the studies (male gender: n = 204, 59.1% compared to female gender: n = 141, 40.9%). The majority of the cases belonged to White (Caucasian) (n = 441, 53.3%), Asian (n = 205, 24.8%), Indian (n = 71, 8.6%), and Black (n = 51, 6.2%) ethnicities. The overall pooled proportions of children with laboratory-confirmed COVID-19 who had bacterial, fungal, and respiratory viral coinfections were 4.73% (95% CI 3.86 to 5.60, n = 445, 34 studies, I2 85%, p < 0.01), 0.98% (95% CI 0.13 to 1.83, n = 17, six studies, I2 49%, p < 0.08), and 5.41% (95% CI 4.48 to 6.34, n = 441, 32 studies, I2 87%, p < 0.01), respectively. Children with COVID-19 in the ICU had higher coinfections compared to ICU and non-ICU patients, as follows: respiratory viral (6.61%, 95% CI 5.06−8.17, I2 = 0% versus 5.31%, 95% CI 4.31−6.30, I2 = 88%) and fungal (1.72%, 95% CI 0.45−2.99, I2 = 0% versus 0.62%, 95% CI 0.00−1.55, I2 = 54%); however, COVID-19 children admitted to the ICU had a lower bacterial coinfection compared to the COVID-19 children in the ICU and non-ICU group (3.02%, 95% CI 1.70−4.34, I2 = 0% versus 4.91%, 95% CI 3.97−5.84, I2 = 87%). The most common identified virus and bacterium in children with COVID-19 were RSV (n = 342, 31.4%) and Mycoplasma pneumonia (n = 120, 23.1%). Conclusion: Children with COVID-19 seem to have distinctly lower rates of bacterial, fungal, and/or respiratory viral coinfections than adults. RSV and Mycoplasma pneumonia were the most common identified virus and bacterium in children infected with SARS-CoV-2. Knowledge of bacterial, fungal, and/or respiratory viral confections has potential diagnostic and treatment implications in COVID-19 children.

Performance Analysis of Novel Nucleic Acid Detection Kit for Mycoplasma pneumoniae

Respiratory tract infections caused by Mycoplasma pneumoniae is a serious risk for child health. It has been difficult to prevent and control for a variety of reasons; therefore, timely diagnosis is particularly important for treatment of patients. At present, the rapid M pneumoniae test kits based on nucleic acid amplification have been commercialized and used as primary diagnostic tools for M pneumoniae infection, but current kits are time-consuming, which is difficult to meet the requirement for accurate and rapid diagnosis of M pneumoniae during epidemics. Rapid and accurate test kits are urgently required to diagnose M pneumoniae infection. In this article, we evaluated the performance of a novel nucleic acid detection kit (A) for M pneumoniae from feasibility and sensitivity, and compared it with kit B. Results showed this kit has the advantage of being rapid, sensitive, and specific, which meets the demands for the diagnosis of M pneumoniae infection in clinical settings.

Analysis of national surveillance of respiratory pathogens for community-acquired pneumonia in children and adolescents

Background

Respiratory infections among children, particularly community-acquired pneumonia (CAP), is a major disease with a high frequency among outpatient and inpatient visits. The causes of CAP vary depending on individual susceptibility, the epidemiological characteristics of the community, and the season. We performed this study to establish a nationwide surveillance network system and identify the causative agents for CAP and antibiotic resistance in Korean children with CAP.

Methods

The monitoring network was composed of 28 secondary and tertiary medical institutions. Upper and lower respiratory samples were assayed using a culture or polymerase chain reaction (PCR) from August 2018 to May 2020.

Results

A total of 1023 cases were registered in patients with CAP, and PCR of atypical pneumonia pathogens revealed 422 cases of M. pneumoniae (41.3%). Respiratory viruses showed a positivity rate of 65.7% by multiplex PCR test, and human rhinovirus was the most common virus, with 312 cases (30.5%). Two hundred sixty four cases (25.8%) were isolated by culture, including 131 cases of S. aureus (12.8%), 92 cases of S. pneumoniae (9%), and 20 cases of H. influenzae (2%). The cultured, isolated bacteria may be colonized pathogen. The proportion of co-detection was 49.2%. The rate of antibiotic resistance showed similar results as previous reports.

Conclusions

This study will identify the pathogens that cause respiratory infections and analyze the current status of antibiotic resistance to provide scientific evidence for management policies of domestic respiratory infections. Additionally, in preparation for new epidemics, including COVID-19, monitoring respiratory infections in children and adolescents has become more important, and research on this topic should be continuously conducted in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07263-z.

The value of interleukin-27 for differentiating tuberculous pleural effusion from Mycoplasma pneumoniae pneumonic effusion in children

OBJECTIVES

The early diagnosis of tuberculous pleural effusion (TPE) is challenging due to the difficulty of isolating Mycobacterium tuberculosis, and pleural biomarkers are an optional choice. Recent studies showed that interleukin-27 (IL-27) appears to be a new accurate biomarker for TPE in adults and no related studies were reported in children. In this study, we aimed to evaluate the potential value of IL-27 in pediatric tuberculous pleurisy by detecting its levels in pleural fluid and serum.

METHODS

A total of 48 children with TPE and 64 children with severe Mycoplasma pneumoniae (MP) pneumonic effusion (SMPPE) were enrolled in this study. IL-27 concentrations were measured in serum and pleural fluid. The diagnostic yield of IL-27 was evaluated using receiver operating characteristic (ROC) curves.

RESULTS

The level of p-IL-27 in TPE showed statistically no significant difference when compared with SMPPE (p > 0.05). However, pleural fluid IL-27 (p-IL-27) / serum IL-27 (s-IL-27) ratio in TPE were significantly much higher than those in SMPPE (p < 0.05). By the analysis of the ROC curves, the diagnostic sensitivity and specificity of the p-IL-27/s-IL-27 ratio were 100% and 48.44%, respectively (cutoff value of 1.0280). The area under the ROC curve for p-IL-27/s-IL-27 was 0.7295.

CONCLUSION

Pleural fluid IL-27 alone was not accurate in distinguishing pediatric TPE from SMPPE, which was different from the diagnostic value of IL-27 in adult studies due to the different disease spectra between children and adults. Our results implied that the p-IL-27/s-IL-27 ratio had a potential value in distinguishing TPE from SMPPE. However, the specificity of IL-27 was relatively lower and it is necessary to find a more specific marker in tuberculous pleurisy of children.

The investigation of P1 gene in Mycoplasma pneumonia isolated from atypic pneumonia by molecular methods, determine IgG antibody and MIC to ciprofloxacin antibiotic

Mycoplasma pneumoniae, which causes atypical pneumonia, is a well-established pathogen of the respiratory tract. This bacterium is intrinsically susceptible to fluoroquinolones. But recently, drug-resistant forms of this bacterium have been reported. This study aims to determine the prevalence of this bacterium by ELISA and PCR and MIC to ciprofloxacin. The clinical samples (blood and nasopharyngeal swab) were collected from 100 patients, who were referred to selective hospitals in Tehran with respiratory complaints, were enrolled in 2017. Nasopharyngeal swab sample collections were cultured on PPLO broth and PPLO agar. After culturing and DNA extraction, PCR was performed by specific P1 genes primers. Ciprofloxacin's MIC of Mycoplasma pneumonia isolated was determined by the Micro-broth dilution method. The serum of IgG antibody titers was also measured by ELISA Mycoplasma pneumonia. In this study, out of 100 samples, 12 bacteria were isolated on PPLO agar. Using specific primers, 7 samples of Mycoplasma speciesism-specific were positive for the presence of M.pneumoniae and 2 Ciprofloxacin resistant isolates were evaluated. ELISA results show that IgG titer antibody is existent in 19 samples and 5 samples are intermediate as well. IgG antibody titer average in the whole sample is 27/66 U/ml, but it is in Positive samples by P1 PCR is 45/75 U/ml. This study showed that PCR is a sensitive and reliable method for rapid detection of M. pneumoniae bacteria in respiratory infectious samples, but the results of this method are different from the ELISA method. Additionally, it seems that the resistance to ciprofloxacin is relatively common among M. pneumoniae.

Community-Acquired Respiratory Distress Syndrome Toxin: Unique Exotoxin for M. pneumoniae

Mycoplasma pneumoniae infection often causes respiratory diseases in humans, particularly in children and adults with atypical pneumonia and community-acquired pneumonia (CAP), and is often exacerbated by co-infection with other lung diseases, such as asthma, bronchitis, and chronic obstructive pulmonary disorder. Community-acquired respiratory distress syndrome toxin (CARDS TX) is the only exotoxin produced by M. pneumoniae and has been extensively studied for its ADP-ribosyltransferase (ADPRT) activity and cellular vacuolization properties. Additionally, CARDS TX induces inflammatory responses, resulting in cell swelling, nuclear lysis, mucus proliferation, and cell vacuolization. CARDS TX enters host cells by binding to the host receptor and is then reverse transported to the endoplasmic reticulum to exert its pathogenic effects. In this review, we focus on the structural characteristics, functional activity, distribution and receptors, mechanism of cell entry, and inflammatory response of CARDS TX was examined. Overall, the findings of this review provide a theoretical basis for further investigation of the mechanism of M. pneumoniae infection and the development of clinical diagnosis and vaccines.

A retrospective study of azithromycin and ceftizoxime for the management of children with Mycoplasma pneumoniae pneumonia

The aim of this study was to compare the clinical efficacy of azithromycin and ceftizoxime (AC) and erythromycin and amoxicillin/sulbactam (EAS) in the treatment of children with Mycoplasma pneumoniae pneumonia (MPP).In this retrospective study, a total of 92 eligible children with MPP were included, and they were divided into a treatment group (n = 46) and a control group (n = 46). All patients were treated with intravenous ambroxol, and nebulized inhalation of budesonide and terbutaline. In addition, patients in the treatment group received AC. Patients in the control group underwent EAS. All patients in both groups were treated for a total of 10 days. Outcomes consist of erythrocyte sedimentation rate, C-reactive protein, serum lactate dehydrogenase, and interleukin 6, fever clearance time, time of cough disappearance, time of rale disappearance, time of signs disappeared by X-ray, and adverse events. All outcomes were measured after 10-day treatment.After treatment, patients who received AC exerted better improvements in erythrocyte sedimentation rate (P < .01), C-reactive protein (P < .01), serum lactate dehydrogenase (P < .01), interleukin 6 (P < .01), fever clearance time (P < .01), time of cough disappearance (P < .01), time of rale disappearance (P < .01), and time of signs disappeared by X-ray (P < .01), than those in patients who received EAS. In addition, there were not significant differences in adverse events between 2 groups.The results of this study showed that AC may benefit more than EAS for the children with MPP.

Ribosomal RNA‑depleted RNA sequencing reveals the pathogenesis of refractory Mycoplasma pneumoniae pneumonia in children

Pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae) is a major cause of community-acquired pneumonia in children. In some cases, M. pneumoniae pneumonia (MPP) can develop into refractory MPP (RMPP), which shows no clinical or radiological response to macrolides, and can progress to severe and complicated pneumonia. However, the pathogenesis of RMPP remains poorly understood. The present study aimed to identify target genes that could be used as biomarkers for the clinical diagnosis of early-stage RMPP through high-throughput sequencing technology. The differences in long non-coding (lnc)RNAs, mRNAs and circular (circ)RNAs were examined between whole-blood samples from two patients with non-refractory MPP (NRMPP), two patients with RMPP and three healthy children using ribosomal (r)RNA-depleted RNA-sequencing techniques and an integrated mRNA/circRNA analysis. A total of 17 lncRNAs (four upregulated and 13 downregulated), 18 mRNAs (six upregulated and 12 downregulated) and 24 circRNAs (12 upregulated and 12 downregulated) were the most significantly differentially expressed (P<0.05) between the NRMPP and RMPP groups. Upon functional analysis, the significantly differentially expressed genes encoded by the targeting mRNAs (prostaglandin-endoperoxide synthase 2, IL-8 and fos-like antigen 1) were screened and identified to be enriched in the ‘IL-17 signaling pathway’. Furthermore, the key circRNAs in the NRMPP and RMPP comparative groups were primarily enriched in ‘herpes simplex virus 1 infection’, ‘viral carcinogenesis’ and ‘RNA transport’. In the present study, a comprehensive analysis of the differences between the NRMPP and RMPP cases was performed based on rRNA-depleted RNA-sequencing techniques, and the selected genes and circRNAs may be closely associated with the complex pathogenesis of RMPP.

Multiple anatomic sites of infarction in a pediatric patient with M. pneumoniae infection, a case report

Background

Although M. pneumoniae (M. pneumoniae) infections have been associated with various extrapulmonary manifestations, there have been very few documented cases of thrombotic events in pediatrics, and none to our knowledge with such extensive involvement as the patient described here. We aim to contribute to the urgency of discovering the mechanism of the coagulopathy associated with M. pneumoniae infections.

Case presentation

This 10-year-old boy was admitted after 2 weeks of fever, sore throat, worsening cough, and progressive neck and back pain. During hospitalization, he developed clots in several different organs: bilateral pulmonary emboli, cardiac vegetations, multiple splenic infarcts, and deep venous thromboses in three of four extremities. He was treated with long-term antibiotics and anticoagulation, and fully recovered.

Conclusions

This is the first case known to us of a child with an extensive number of thrombotic events in multiple anatomic sites associated with M. pneumoniae infection. The mechanism by which M. pneumoniae infection is related to thrombotic events is not fully understood, but there is evidence that the interplay between the coagulation pathways and the complement cascade may be significant. This patient underwent extensive investigation, and was found to have significant coagulopathy, but minimal complement abnormalities. By better understanding the mechanisms involved in complications of M. pneumoniae infection, the clinician can more effectively investigate the progression of this disease saving time, money, morbidity, and mortality.

Macrolide-Resistant and Macrolide-Sensitive Mycoplasma pneumoniae Pneumonia in Children Treated Using Early Corticosteroids

We have found that early corticosteroid therapy was effective for reducing morbidity during five Korea-wide epidemics. We evaluated the clinical and laboratory parameters of 56 children who received early corticosteroid treatment for pneumonia that was caused by macrolide-resistant Mycoplasma pneumoniae (M. pneumoniae) or macrolide-sensitive M. pneumoniae between July 2019 and February 2020. All subjects had dual positive results from a PCR assay and serological test, and received corticosteroids within 24–36 h after admission. Point mutation of residues 2063, 2064, and 2067 was identified in domain V of 23S rRNA. The mean age was 6.8 years and the male:female ratio was 1.2:1 (31:25 patients). Most of the subjects had macrolide-resistant M. pneumoniae (73%), and all mutated strains had the A2063G transition. No significant differences in clinical and laboratory parameters were observed between macrolide-resistant and macrolide-sensitive M. pneumoniae groups that were treated with early dose-adjusted corticosteroids. Higher-dose steroid treatment may be needed for patients who have fever that persists for >48 h or increased biomarkers such as lactate dehydrogenase concentration at follow-up despite a usual dose of steroid therapy.

Clinical characteristics of refractory mycoplasma pneumoniae pneumonia in children treated with glucocorticoid pulse therapy

BACKGROUND

To observe the effect of corticosteroids in the treatment of children with refractory Mycoplasma pneumoniae pneumonia (RMPP) under different doses, to summarize the clinical features of children treated with glucocorticoid pulse therapy.

METHODS

The clinical data of 125 children with RMPP hospitalized in Tianjin Children's Hospital from September 2018 to October 2019 were retrospectively analyzed. They were divided into two groups according to the dose of hormone. Compare the clinical features, laboratory findings, and imaging between the two groups, and use meaningful related indicators as ROC curves to find reference indicators for pulse therapy.

RESULTS

(1) The median age of the group II was older than that of the group I(P < 0.05). (2) We found more severe presentations, higher incidence of extra-pulmonary complications and more serious radiological findings in group II, which needed oxygen more often, higher the hormone, higher usage rate of gamma globulin, higher usage rate of bronchoscopy, and higher incidence of plastic bronchitis(P < 0.05). (3) WBC, CRP, LDH, FER, D-D dimer, APTT, TT, PCT, IL-6 and the percentage of neutrophils in peripheral blood in Group II were higher than those in Group I(P < 0.05). (4) In ROC curve analysis, CRP, LDH, FER, and neutrophils of leukocyte classification were independent related factors that could be used as valuable predictors of methylprednisolone pulse therapy for RMPP in children. The cut-off values were CRP44.45 mg/L, LDH590IU/L, FER411ng/L, and neutrophils in leukocyte classification were 73.75%, respectively.

CONCLUSION

CRP ≥ 44.45 mg/L, LDH ≥ 590 IU/L, FER ≥ 411 ng/L, neutrophil≥73.75%, lung consolidation, and pleural effusion may be predictors that guide the treatment of RMPP with pulse dose of GC.

Clinical significance of D-dimer levels in refractory Mycoplasma pneumoniae pneumonia

BACKGROUND

The levels of serum D-dimer (D-D) in children with Mycoplasma pneumoniae pneumonia (MPP) were assessed to explore the clinical significance of D-D levels in refractory MPP (RMPP).

METHOD

A total of 430 patients with MPP were enrolled between January 2015 and December 2015 and divided into a general MPP (GMPP) group (n = 306) and a RMPP group (n = 124). Clinical data, D-D level, white blood cell (WBC) count, proportion of neutrophils (N%), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), alanine transaminase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) were compared between the two groups. Multivariate logistic regression was performed to identify independent predictors of RMPP.

RESULTS

(1) Hospitalization time, preadmission fever duration, total fever duration, WBC, N %, CRP, LDH, ESR, ALT, AST, and D-D were significantly higher in the RMPP group than those in the GMPP group (all P < 0.05). (2) Correlation analysis showed that D-D was positively correlated with WBC, CRP, ESR, and LDH, and could be used to jointly evaluate the severity of the disease. (3) Multivariate logistic regression analysis identified preadmission fever duration, CRP, LDH and DD as independent risk factors for RMPP (all P < 0. 05). D-D had the highest predictive power for RMPP (P < 0.01). The D-D level also had a good ability to predict pleural effusion and liver injury (all P < 0.01).

CONCLUSION

Serum D-D levels were significantly increased in patients with RMPP, indicating that excessive inflammatory response and vascular endothelial injury with prolonged duration existed in this patient population. Increased levels of serum D-D may be used as an early predictor of RMPP and the occurrence of complications. Our findings provide a theoretical basis for the early diagnosis of RMPP, early intervention and excessive inflammatory response in the pathogenesis of mycoplasma.

Chest CT Findings and Differential Diagnosis of Mycoplasma pneumoniae Pneumonia and Mycoplasma pneumoniae Combined with Streptococcal Pneumonia in Children

BACKGROUND

In this day and age, 17% of children less than 5 years of age died of pneumonia; it is the common cause of children death. It is one of the main children respiratory infectious diseases, i.e., mycoplasma pneumonia (MP). The imaging examination can be adopted to quickly observe the morphology and scope of the pulmonary lesions and know the effect of disease treatment and subsequent changes in the disease in order to provide a basis for treatment. Therefore, the most commonly applied technology for detecting pneumonia in children is imaging technology, including chest X-ray and CT.

OBJECTIVES

The main objective of the work is to investigate the chest computed tomography (CT) findings of children patients with Mycoplasma pneumoniae pneumonia (MPP) and MP combined with streptococcal pneumonia (SP). The mixed infection of MP and SP is very common clinically, and the diagnosis of this type of mixed pneumonia is a critical research topic faced by pediatric respiratory physicians. The comparison is done on the incidence of bronchial and pulmonary interstitial lesions, the degree of lymph node enlargement, the volume and depth of pleural effusion, and the location and morphology of the pulmonary lesions in the chest CT images of children patients from the two groups.

METHODS

There were comparisons on the incidence of bronchial and pulmonary interstitial lesions, the degree of lymph node enlargement, the volume and depth of pleural effusion, and the location and morphology of the pulmonary lesions in the chest CT images of children patients from the two groups. All the experiments are done in the MATLAB.

RESULTS

The results showed that the proportions of reticular shadow, ground glass shadow, bronchial inflation phase, tube wall thickening, and vascular bundle thickening on the CT images of children patients from the MPP group were dramatically higher than those of the MP + SP group (P < 0.05). The maximum transverse diameter of enlarged lymph node in children patients from the MPP group was obviously larger than the diameter of the MP + SP group (P < 0.05). The number of children patients with pleural effusion was 22 in the MP + SP group, which was greatly higher than the MPP group (P < 0.05).

CONCLUSION

In conclusion, the chest CT images of children patients from the MPP group were mainly pulmonary interstitial changes. Furthermore, the alveolar inflammation could be observed on the CT images shown when children patients were combined with SP infection. The more obvious manifestations were that the flaky shadows appeared in the lungs, the pleural effusion became thicker, and the transverse diameters of enlarged lymph nodes were bigger.

Comparative efficacy and safety of traditional Chinese patent medicine in the treatment of Mycoplasma pneumoniae pneumonia in children: A protocol for systematic review and meta-analysis

BACKGROUND

Mycoplasma pneumoniae pneumonia (MPP) is a common respiratory disease in children. Its incidence rate is increasing year by year. The drug resistance rate of macrolide antibiotics and other conventional treatment methods is higher, and there are limitations in clinical application. Traditional Chinese patent medicine (TCPM) is a powerful weapon to treat this disease. At present, there is no comparison of the safety and effectiveness of multiple TCPMs in the treatment of MPP in children. Therefore, we take the method of network meta-analysis to systematically compare the efficacy of various TCPMs in the treatment of this disease.

METHODS

We will conduct comprehensive searches of Cochrane Library, PubMed, Web of Science, Clinical Trials, China National Knowledge Infrastructure, Chinese Scientific Journals Database, Chinese BioMedical Literature, Wanfang Database, and other electronic databases. The time frame is set from the establishment of the database to October 2020. All randomized controlled trials that meet the inclusion criteria will be included in this study. The 2 researchers will independently screen the literature according to the inclusion criteria, extract the data, and assess the bias risk of the included study. We will evaluate all the obtained data and evidence through Bayesian network meta-analysis, and use Stata 15.0 to process and analyze the data.

RESULTS

Through this study, we will evaluate the efficacy and safety of a variety of TCPMs for the treatment of MPP in children.

CONCLUSION

The purpose of this study is to provide a strong reference for clinical application of TCPMs in the treatment of MPP in children, and to provide an important basis for clinicians to make correct judgments and put forward accurate treatment plans.

ETHICS AND DISSEMINATION

This review does not involve any human or animal experiments and therefore does not require ethical approval.

INPLASY REGISTRATION NUMBER

INPLASY 2020100108.

The solution on enigmas in COVID-19: the protein-homeostasis-system hypothesis

Infectious diseases, including coronavirus disease 2019 (COVID-19), are representative, of which etiology is known in all human diseases. However, many enigmas persist in relation to COVID-19, including different clinical phenotypes and incubation periods across individuals, species-specificity, appearance of cytokine storm and lymphopenia, and the mechanism of damage to organ cells. Current immunological concepts have limitations to explain these unsolved issues. Meanwhile, results of clinical, pathological, and animal studies have suggested that the virus itself is not a direct cause of acute injury to the lung or other organ cells. For better understanding of COVID-19, a presumed immunopathogenesis of COVID-19 is presented under the protein-homeostasis-system hypothesis; every disease, including COVID-19, has associated etiological substances, and the host immune system controls these diverse substances according to the size and biochemical property. These etiological substances, inducing inflammation and subsequent tissue injury, are smaller substances derived from virus-infected cells. Initially acting nonspecific adaptive immune reaction with cytokine imbalance may be responsible for target cell injury. Furthermore, substances from initial target cell injury and secondary bacterial invasion can induce further inflammation if released from local or systemic circulation. COVID-19 patients with pneumonia show hypercytokinemia with lymphocytopenia corresponding to the severity of pneumonia at early stages. Thus, early immune-modulator treatment, including corticosteroids and intravenous immunoglobulin, has an immunological rationale. It could help reduce the morbidity and possibly mortality of older patients with underlying conditions.

Immunopathogenesis of COVID-19 and early immunomodulators

The novel coronavirus disease 2019 (COVID-19) is spreading globally. Although its etiologic agent is discovered as severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), there are many unsolved issues in COVID-19 and other infectious diseases. The causes of different clinical phenotypes and incubation periods among individuals, species specificity, and cytokine storm with lymphopenia as well as the mechanism of damage to organ cells are unknown. It has been suggested that in viral pneumonia, virus itself is not a direct cause of acute lung injury; rather, aberrant immune reactions of the host to the insults from viral infection are responsible. According to its epidemiological and clinical characteristics, SARS-CoV-2 may be a virus with low virulence in nature that has adapted to the human species. Current immunological concepts have limited ability to explain such unsolved issues, and a presumed immunopathogenesis of COVID-19 is presented under the proteinhomeostasis-system hypothesis. Every disease, including COVID-19, has etiological substances controlled by the host immune system according to size and biochemical properties. Patients with severe pneumonia caused by SARS-CoV-2 show more severe hypercytokinemia with corresponding lymphocytopenia than patients with mild pneumonia; thus, early immunomodulator treatment, including corticosteroids, has been considered. However, current guidelines recommend their use only for patients with advanced pneumonia or acute respiratory distress syndrome. Since the immunopathogenesis of pneumonia may be the same for all patients regardless of age or severity and the critical immune-mediated lung injury may begin in the early stage of the disease, early immunomodulator treatment, including corticosteroids and intravenous immunoglobulin, can help reduce morbidity and possibly mortality rates of older patients with underlying conditions.

Impact of Epstein-Barr virus coinfection in Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is one of the most common pathogens of respiratory infection in children, while Epstein-Barr virus (EBV) infection is usually subclinical in immunocompetent children. Although single MP infection is common enough, MP and EBV coinfection have received little attention. Especially, the pathogenic role of EBV in lung when coinfection with MP, has not been clarified. The purpose of this study was to investigate the impact of EBV on MP pneumonia (MPP) in hospitalized children. We retrospectively reviewed the clinical data of MPP children who underwent screening for EBV by polymerase chain reaction in bronchoalveolar lavage fluid during hospitalization in 2014. Of total 147 patients, 68 patients were in the MP group and 79 were in the MP/EBV coinfection group. We found longer fever duration and higher CRP, IgA, IgG, interleukin-2 (IL-2), percentage of peripheral neutrophils levels, higher incidence of pulmonary consolidation and percentage of refractory MPP in coinfection group, when compared to those in MP group. In ROC curve analysis, IL-2 was useful for differentiating patients with coinfection from those with MP infection. Logistic regression analysis showed that the IL-2 ≥ 3.35 pg/ml (OR = 3.677) was a significant predictor regarding to MP/EBV coinfection. In conclusion, coinfection of EBV and MP poses a higher risk for prolonged symptoms. IL-2 could be used as a good predictor of coinfection.

Meta-analysis of the Clinical Efficacy and Safety of High- and Low-dose Methylprednisolone in the Treatment of Children With Severe Mycoplasma Pneumoniae Pneumonia

BACKGROUND

Mycoplasma pneumoniae pneumonia is generally a self-limiting disease, but it can develop into severe Mycoplasma pneumoniae pneumonia (SMPP). Immunologic mechanisms are thought to play an important role in the pathogenesis of SMPP. Therefore, the use of systemic glucocorticoids may have beneficial effects. However, to date, the use of glucocorticoid therapy in SMPP is limited to small case series, and the glucocorticoid dosage for children with SMPP has not been established.

METHODS

Here, we used a meta-analysis method to collect data from randomized control trials of different doses of methylprednisolone in SMPP to assess the safety and efficacy of treatment with low- versus high-dose methylprednisolone in children with SMPP.

RESULTS

We included 13 Chinese randomized control trials that included 1049 children. The high- and low-dose groups were comprised of 524 and 525 children, respectively. The high-dose group was significantly more effective than the low-dose group in clinical efficacy [risk ratio = 1.30, 95% confidence interval (CI) (1.23, 1.38), P < 0.05]. In addition, compared with low-dose methylprednisolone, high-dose methylprednisolone significantly shortened hospital stays and antipyretic therapy, pulmonary rales disappearance, cough disappearance and pulmonary shadow absorption times. There was no significant difference in adverse events between the high- and low-dose groups: risk ratio= 0.85, 95% CI (0.53, 1.36), P > 0.05.

CONCLUSIONS

We conclude that high-dose methylprednisolone is effective in the treatment of SMPP without increasing the incidence of adverse reactions.

Real-Time PCR and Quantitative Culture for Mycoplasma pneumoniae Load in Pharyngeal Swabs from Children at Preliminary Diagnosis and Discharge

Background

Extensive studies have focused on the diagnosis and treatment of Mycoplasma pneumoniae infection; however, rare studies investigated the posttreatment conditions. We analyzed the carrying status of M. pneumoniae in the respiratory tract of children before and after treatment.

Methods

Ninety-two children with M. pneumoniae pneumonia were included in this study. Clinical data were obtained from each patient, and pharyngeal swab sampling was performed at preliminary diagnosis and discharge. Real-time PCR and dilution quantitative culture were utilized to determine the DNA quantification and number of viable M. pneumoniae from samples collected upon preliminary diagnosis and discharge.

Results

All the 92 cases showed DNA positivity upon preliminary diagnosis, serum IgM antibody was detected in 80 patients, and positivity of M. pneumoniae culture was observed in 82 cases. Upon discharge, the M. pneumoniae nucleotide and culture positivity were detected in 87 and 49 cases, respectively. The content of viable M. pneumoniae was 10–10⁴ CCU/mL and 10–10² CCU/mL in the preliminary diagnosis samples and discharge samples, respectively.

Conclusions

Real-time PCR was rapid and effective for the qualitative diagnosis of M. pneumoniae at the early stage, but it cannot be used to evaluate the prognosis of patients with M. pneumoniae infection. Quantitative analysis for M. pneumoniae DNA could not directly reflex the viable strain content.

Efficacy of glucocorticoids for the treatment of macrolide refractory mycoplasma pneumonia in children: meta-analysis of randomized controlled trials

Background

Mycoplasma pneumoniae is one of the most common pathogens causing community acquired pneumonia in children. Although the rate of macrolide-refractory Mycoplasma pneumoniae (MRMP) has increased, systemic glucocorticoids as a treatment option has not been validated yet. The purpose of this study was to assess the efficacy of glucocorticoids add-on in the treatment of MRMP in children through systematic review and meta-analysis.

Methods

Data sources

A systematic literature search was conducted using ten electronic bibliographic databases including English, Korean, Chinese and Japanese languages, up to March 8, 2018.

Study selection

The study was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses checklist and selected randomized control trials which compared the efficacy of glucocorticoids add-on to macrolide in the treatment of MRMP in children.

Data extraction

Two independent reviewers extracted: primary outcomes as hospital days, fever duration, and change in C-reactive protein (CRP) and main analysis was performed through meta-analysis with random effects model.

Results

Twenty-four unique randomized controlled trials met the inclusion criteria. The mean length of hospital stay in glucocorticoids treatment group was significantly shorter than that in conventional macrolide-treatment group (Weighted mean difference (WMD) = − 4.03 days). The mean length of fever duration was significantly shorter in the glucocorticoid treatment group in comparison with the conventional treatment group (WMD = -3.32 days). Level of CRP after treatment was significantly lower in the glucocorticoid treatment group than that in the conventional treatment group (WMD = -16.03). Sensitivity analysis and subgroup analysis showed no significant improvement in heterogeneity. As limitations of the study, most of the studies included were from a single country and we were unable to control for heterogeneity across interventions, lack of standardized measures, and different time points of assessments across studies.

Conclusions

Glucocorticoid add-on treatment for MRMP can significantly shorten the duration of fever and hospital stay and decrease the level of CRP. These results should be confirmed by adequately powered studies in the future.

Comparison of azithromycin and erythromycin in the treatment of mycoplasma pneumonia in children

Objective:

To study and compare the clinical effects of azithromycin and erythromycin on children with mycoplasma pneumonia.

Methods:

Total 132 children with mycoplasma pneumonia who were admitted to our hospital between November 2017 and September 2018 were selected as the research subjects. All the children were divided into an observation group and a control group according to random number table, 66 each. The observation group was treated with azithromycin, while the control group was treated with erythromycin. The therapeutic effect, incidence of adverse reactions and disappearance time of clinical symptoms were compared between the two groups.

Results:

The total efficacy of the observation group was 98.04%, and that of the control group was 74.51%; there was a significant difference (X²=7.184, P=0.007). The incidence of adverse reactions in the observation group was 15.69%, significantly lower than that in the control group (41.18%) (X²=6.376, P=0.002). The disappearance of fever, cough, rale and X ray shadow of the observation group was significantly earlier than that of the control group, and the difference was statistically significant (P<0.05).

Conclusion:

Compared with erythromycin, azithromycin is more effective in the treatment of mycoplasma pneumonia in children. Azithromycin can further shorten the improvement time of clinical symptoms and signs and has few adverse reactions and high safety. It is worth clinical application.

[Association of YKL-40 in bronchoalveolar lavage fluid with airway damage in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To investigate the association of YKL-40 in bronchoalveolar lavage fluid (BALF) with airway damage in children with Mycoplasma pneumoniae pneumonia (MPP).

METHODS

A total of 60 children with MPP who were admitted to the hospital were enrolled as the MPP group, and 12 children with bronchial foreign bodies were enrolled as the control group. According to the imaging findings, the MPP group was further divided into 3 subgroups: pulmonary patchy shadow (n=34), pulmonary consolidation (n=19) and pulmonary ground-glass opacity (n=7). According to the bronchoscopic findings, the MPP group was further divided into 3 subgroups: mucosal congestion/edema (n=38), mucous secretion (n=18) and plastic bronchitis (n=4). The clinical manifestations and laboratory characteristics of the children with MPP were analyzed, the expression of YKL-40 in BALF was measured.

RESULTS

The MPP group had significantly higher levels of serum lactate dehydrogenase and BALF YKL-40 than the control group (P<0.05). The pulmonary consolidation subgroup had significantly higher levels of serum C-reactive protein and lactate dehydrogenase than the pulmonary patchy shadow subgroup (P<0.05), and the pulmonary consolidation and pulmonary ground-glass opacity subgroups had a significantly higher level of BALF YKL-40 than the pulmonary patchy shadow subgroup (P<0.05). The plastic bronchitis subgroup had a significantly higher level of BALF YKL-40 than the mucous secretion and mucosal congestion/edema subgroups (P<0.05). The mucous secretion and plastic bronchitis subgroups had a significantly higher proportion of children with shortness of breath than the mucosal congestion/edema subgroup (P<0.05). The plastic bronchitis subgroup had significantly higher serum levels of C-reactive protein and lactate dehydrogenase than the mucosal congestion/edema subgroup (P<0.05).

CONCLUSIONS

The level of BALF YKL-40 is associated with airway damage and disease severity in children with MPP.

Predictive Model for Discrimination of Tuberculous Pleural Effusion From Severe Mycoplasma pneumoniae Pneumonic Effusion in Children

BACKGROUND

Tuberculous pleural effusion (TPE) is often misdiagnosed as severe Mycoplasma pneumoniae pneumonic effusion (SMPPE) in children at early stage. The aim of this study was to develop a predictive model based on clinical and laboratory indices to make accurate differential diagnosis.

METHODS

Patients included in this study were 167 children (83 patients with TPE and 84 with SMPPE), containing 117 patients for predictive model development and 50 patients for external validation. Multivariate logistic regression analysis was conducted to select potentially useful characteristics for discrimination of TPEs. External validation was performed for model evaluation.

RESULTS

Multivariate analysis revealed that blood neutrophils and serum lactate dehydrogenase were significant independent factors to discriminate between TPEs and SMPPEs. The results indicated that blood neutrophils ≤69.6% and concentration of serum lactate dehydrogenase ≤297 U/L were the extremely important discrimination factors of TPEs. The area under the receiver operating characteristic curve of the model was 0.9839. The accuracy rate, sensitivity and specificity of the model were 94.02%, 98.28% and 89.83%, respectively. Meanwhile, the accuracy rate of the external validation from the 50 patients was 94.0%.

CONCLUSIONS

Applying a predictive model with clinical and laboratory indices can facilitate the differential diagnosis of TPE from SMPPE in children, which seems helpful when a microbiologic or histologic diagnosis of pleural tuberculosis could not be established.

Impact and clinical profiles of Mycoplasma pneumoniae co-detection in childhood community-acquired pneumonia

Background

Increasing number of hospitalized children with community acquired pneumonia (CAP) is co-detected with Mycoplasma pneumoniae (Mp). The clinical characteristics and impact of Mp co-detected with other bacterial and/or viral pathogens remain poorly understood. The purpose of this study was to evaluate the demographic and clinical features of CAP children with Mp mono-detection and Mp co-detection.

Methods

A total of 4148 hospitalized children with CAP were recruited from January to December 2017 at the Children’s Hospital of Hebei Province, affiliated to Hebei Medical University. A variety of respiratory viruses, bacteria and Mp were detected using multiple modalities. The demographic and clinical features of CAP children with Mp mono-detection and Mp co-detection were recorded and analyzed.

Results

Among the 110 CAP children with Mp positive, 42 (38.18%) of them were co-detected with at least one other pathogen. Co-detection was more common among children aged ≤3 years. No significant differences were found in most clinical symptoms, complications, underlying conditions and disease severity parameters among various etiological groups, with the following exceptions. First, prolonged duration of fever, lack of appetite and runny nose were more prevalent among CAP children with Mp-virus co-detection. Second, Mp-virus (excluding HRV) co-detected patients were more likely to present with prolonged duration of fever. Third, patients co-detected with Mp-bacteria were more likely to have abnormal blood gases. Additionally, CAP children with Mp-HRV co-detection were significantly more likely to report severe runny nose compared to those with Mp mono-detection.

Conclusion

Mp co-detection with viral and/or bacterial pathogens is common in clinical practice. However, there are no apparent differences between Mp mono-detection and Mp co-detections in terms of clinical features and disease severity.

Changes in the Treatment Strategies for Helicobacter pylori Infection in Children and Adolescents in Korea

The policies developed for the treatment of Helicobacter pylori infection in adults may not be the most suitable ones to treat children and adolescents. Methods used to treat children and adolescents in Europe and North America may not be appropriate for treating children and adolescents in Korea due to differences in epidemiological characteristics of H. pylori between regions. Moreover, the agreed standard guidelines for the treatment of H. pylori infection in children and adolescents in Korea have not been established yet. In this study, the optimal treatment strategy for H. pylori infection control in children and adolescents in Korea is discussed based on these guidelines, and recent progress on the use and misuse of antimicrobial agents is elaborated. Non-invasive as well as invasive diagnostic test and treatment strategy for H. pylori infection are not recommendable in children aged less than ten years or children with body weight under 35 kg, except in cases of clinically suspected or endoscopically identified peptic ulcers. The uncertainty, whether enough antimicrobial concentrations to eradicate H. pylori can be maintained when administered according to body weight-based dosing, and the costs and adverse effects outweighing the anticipated benefits of treatment make it difficult to decide to eradicate H. pylori in a positive non-invasive diagnostic test in this age group. However, adolescents over ten years of age or with a bodyweight of more than 35 kg can be managed aggressively as adults, because they can tolerate the adult doses of anti-H. pylori therapy. In adolescents, the prevention of future peptic ulcers and gastric cancers is expected after the eradication of H. pylori. Bismuth-based quadruple therapy (bismuth-proton pump inhibitor-amoxicillin/tetracycline-metronidazole) with maximal tolerable doses and optimal dose intervals of 14 days is recommended, because in Korea, the antibiotic susceptibility test for H. pylori is not performed at the initial diagnostic evaluation. If the first-line treatment fails, concomitant therapy plus bismuth can be attempted for 14 days as an empirical rescue therapy. Finally, the salvage therapy, if needed, must be administered after the H. pylori antibiotic susceptibility test.

Antimicrobial susceptibility and molecular characteristics of Mycoplasma pneumoniae isolates across different regions of China

Background

In China mainland, most Mycoplasma pneumoniae related studies are carried out in Beijing and Shanghai, while rare studies are performed in the other regions. In this study, we analyzed the molecular biology characteristics and antimicrobial susceptibility of clinical isolates of M. pneumoniae from 5 regions between January 2017 and December 2018.

Methods

Genotyping was performed to 154 M. pneumoniae isolates from 5 cities using PCR and multiple-locus variable-number tandem repeat analysis (MLVA) method. Antimicrobial susceptibility test was performed to all the isolates against 4 antibiotics. Sequencing was performed to the amplification products of the 23S rRNA drug resistant gene.

Results

Genotype I was detected in 118 M. pneumoniae isolates (76.6%), and genotype II was identified in 36 isolates (23.4%). The majority (92.2%) of the MLVA genotypes were 4–5–7-2 and 3–5–6-2, which represented the genotype I and II, respectively. The total macrolide (ML) resistance rate was 79.7%. The minimum inhibitory concentration (MIC) of the erythromycin was in a range of 128- > 256 μg/ml, while that for the azithromycin was 2-32 μg/ml. There were mutations in the 23S rRNA in each ML resistance isolate. Jilin city showed the highest prevalence of genotype I (100%) and ML resistance rate (100%), while Jinan showed the lowest prevalence of genotype I (45.5%) and ML resistance rate (54.5%).

Conclusions

A large variance was identified in the M. pneumoniae genotype and ML resistance among the 5 cities. The proportion of M. pneumoniae with a genotype II genotype (3–5–6-2) showed an increased trend.

Electronic supplementary material

The online version of this article (10.1186/s13756-019-0576-5) contains supplementary material, which is available to authorized users.

Critical combination of initial markers for predicting refractory Mycoplasma pneumoniae pneumonia in children: a case control study

Background

It is unclear whether the responses of refractory and common Mycoplasma pneumoniae (MP) pneumonia to macrolides differ. Hence, this study aimed to identify biomarkers that may be used to distinguish refractory and common pneumonias caused by MP in children at hospital admission.

Methods

The study included 123 children divided into five groups according to infection agent and treatment protocol: Group I included those with MP infection without documented viral infection, treated with only macrolides; Group II included those with MP infection without documented viral infection, treated with a combination of macrolides and methylprednisolone; Group III included those with MP infection and documented viral infection, treated with only macrolides; Group IV included those with viral pneumonia without documented MP infection; Group V was the control group composed of admitted children without MP or a documented viral infection. These five groups were further subdivided into Groups A (including Groups I, III, IV, and V) and B (Group II) according to the responses to macrolide treatment. Concentrations of cytokines interleukin 6, interleukin 17, interleukin 18, and tumor necrosis factor-α, and lactate dehydrogenase, and ferritin of all children were evaluated, and these levels were compared among the groups. Statistical comparisons were made using Kruskal Wallis test and Mann-Whitney U test.

Results

Serum lactate dehydrogenase, interleukin 18, and ferritin concentrations were significantly higher in Group II than in Groups I, III, IV, and V and were significantly higher in Group B than in Group A. When the serum lactate dehydrogenase concentration was 350 IU/L or higher, the sensitivity and specificity for diagnosing refractory MP pneumonia were 73 and 80%, respectively. When the interleukin 18 level was 360 pg/mL or higher, the sensitivity and specificity for diagnosing refractory MP pneumonia were 93 and 70%, respectively. When the ferritin level was 230 pg/mL or higher, the sensitivity and specificity for diagnosing refractory MP pneumonia were 67 and 67%, respectively.

Conclusion

These results suggest that serum lactate dehydrogenase, interleukin 18, and ferritin constitute the critical combination of biomarkers useful for predicting refractory MP pneumonia in children at hospital admission.

Early Corticosteroid Therapy for Mycoplasma pneumoniae Pneumonia Irrespective of Used Antibiotics in Children

Antibiotics’ effect on Mycoplasma pneumoniae (MP) infection still remains controversial. A prospective study of 257 children with MP pneumonia during a recent epidemic (2015–2016) was conducted. All MP pneumonia patients were treated with corticosteroids within 24–36 h after admission. Initially, oral prednisolone (1 mg/kg) or intravenous methylprednisolone (IVMP; 1–2 mg/kg) was administered for mild pneumonia patients, and IVMP (5–10 mg/kg/day) for severe pneumonia patients. If patients showed a persistent fever for 36–48 h or disease progression, additive IVMP (5 mg/kg or 10 mg/kg) was given. Thirty-three percent of patients received only a broad-spectrum antibiotic without a macrolide. The mean age and the male-to-female ratio was 5.6 ± 3.1 years and 1:1, respectively. Seventy-four percent of patients showed immediate defervescence within 24 h, and 96% of patients showed defervescence within 72 h with improvements in clinical symptoms. Three percent of patients (8/257) who received additive IVMP also showed clinical improvement within 48 h without adverse reactions. There were no clinical or laboratory differences between patients treated with a macrolide (n = 172) and without (n = 85). Early corticosteroid therapy might reduce disease morbidity and prevent disease progression in MP pneumonia patients without side effects, and antibiotics may have limited effects on MP infection.

Benefits and risks of therapeutic alternatives for macrolide resistant Mycoplasma pneumoniae pneumonia in children

Although Mycoplasma pneumoniae pneumonia (MPP) has been generally susceptible to macrolides, the emergence of macrolide-resistant MPP (MRMP) has made its treatment challenging. MRMP rapidly spread after the 2000s, especially in East Asia. MRMP is more common in children and adolescents than in adults, which is likely related to the frequent use of macrolides for treating M. pneumoniae infections in children. MRMP is unlikely to be related to clinical, laboratory, or radiological severity, although it likely prolongs the persistence of symptoms and the length of hospital stay. Thereby, it causes an increased burden of the disease and poor quality of life for the patient as well as a societal socioeconomic burden. To date, the only alternative treatments for MRMP are secondary antimicrobials such as tetracyclines (TCs) or fluoroquinolones (FQs) or systemic corticosteroids; however, the former are contraindicated in children because of concerns about potential adverse events (i.e., tooth discoloration or tendinopathy). A few guidelines recommended TCs or FQs as the second-line drug of choice for treating MRMP. However, there have been no evidence-based guidelines. Furthermore, safety issues have not yet been resolved. Therefore, this article aimed to review the benefits and risks of therapeutic alternatives for treating MRMP in children and review the recommendations of international or regional guidelines and specific considerations for their practical application.

Role of Probiotics in Mycoplasma pneumoniae Pneumonia in Children: A Short-Term Pilot Project

Mycoplasma pneumoniae is one of the most common pathogens causing community-acquired pneumonia in children. Mycoplasma pneumoniae pneumonia (MPP) can be successfully treated with azithromycin; however, antibiotic-associated diarrhea (AAD) is a common adverse effect. Increasing evidence suggests that some probiotics may prevent the development of AAD. The present study determined the effects of probiotics (live Clostridium butyricum plus Bifidobacterium infantis) on the prevention and treatment of AAD in children with MPP when co-administered with intravenous azithromycin. Fifty-five children with MPP were enrolled and received azithromycin (10 mg/kg/day; once daily for 7 days) combined with probiotics (starting on the third day of azithromycin treatment; 1,500 mg three times daily); 50 healthy children served as controls. At the end of the trial, the incidence of AAD, fecal microbiota, intestinal mucosal barriers, and systemic inflammation were analyzed using recommended systems biology techniques. No cases of AAD or other adverse events occurred in children with MPP after co-administration of probiotics with azithromycin. A live C. butyricum plus B. infantis preparation partly reconstructed the gut microbiota, especially restoration of bacterial diversity. The indicators of intestinal mucosal barrier function, such as D-lactate, endotoxin, and diamine oxidase, were significantly improved and the systemic inflammation (interleukin 10) was attenuated after probiotic therapy. The present study indicated that co-administration of probiotics with azithromycin is a promising therapy for MPP treatment which could prevent and treat AAD effectively.

Early Diagnosis of Mycoplasma pneumoniae in Children: Simultaneous Amplification and Testing (SAT) Is the Key

Objective: The effective diagnosis of Mycoplasma pneumoniae (MP) pneumonia (MPP) in children has been hampered by the difficulty of achieving an early diagnosis. The simultaneous amplification and testing (SAT) has the potential for early diagnosis of MP in children. Methods: Of the 1,180 children enrolled in this study, 169 were MPP antibody (Ab) seroconversion positive, 641 showed MPP positivity with a single Ab test, and 370 were MPP negative. Sera and pharyngeal swabs were collected for antibody testing and SAT detection, respectively, on admission. When the samples were Ab negative, the paired -Ab test was requested for MP 7 days later. Results: Using the Ab results as the diagnostic standard, the sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV) for SAT were 72.8, 95.1, 97.0, and 61.5%, respectively. SAT had superior diagnostic value in the MPP group who had undergone Ab seroconversion (sensitivity: 82.2%; NPV: 92.1%) and in the short-course group also (sensitivity: 81.0%; NPV: 81.3%). Good agreement was observed between SAT and the paired-Ab results (kappa value = 0.79; P < 0.001), but there was a lack of consistency between SAT and the single-Ab test results on admission (kappa value = 0.54, P < 0.001). Conclusions: SAT is a rapid, sensitive, and specific method for MP diagnosis in pediatric patients. Our results indicate its value as an effective diagnostic tool for detecting MPP at the initial stage of an infection.

Therapeutic Efficacy and Safety of Prolonged Macrolide, Corticosteroid, Doxycycline, and Levofloxacin against Macrolide-Unresponsive Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

We aimed to compare the therapeutic efficacy of prolonged macrolide (PMC), corticosteroids (CST), doxycycline (DXC), and levofloxacin (LFX) against macrolide-unresponsive Mycoplasma pneumoniae (MP) pneumonia in children and to evaluate the safety of the secondary treatment agents.

METHODS

We retrospectively analyzed the data of patients with MP pneumonia hospitalized between January 2015 and April 2017. Macrolide-unresponsiveness was clinically defined with a persistent fever of ≥ 38.0°C at ≥ 72 hours after macrolide treatment. The cases were divided into four groups: PMC, CST, DXC, and LFX. We compared the time to defervescence (TTD) after secondary treatment and the TTD after initial macrolide treatment in each group with adjustment using propensity score-matching analysis.

RESULTS

Among 1,165 cases of MP pneumonia, 190 (16.3%) were unresponsive to macrolides. The proportion of patients who achieved defervescence within 48 hours in CST, DXC, and LFX groups were 96.9% (31/33), 85.7% (12/14), and 83.3% (5/6), respectively. The TTD after initial macrolide treatment did not differ between PMC and CST groups (5.1 vs. 4.2 days, P = 0.085), PMC and DXC groups (4.9 vs. 5.7 days, P = 0.453), and PMC and LFX groups (4.4 vs. 5.0 days, P = 0.283). No side effects were observed in the CST, DXC, and LFX groups.

CONCLUSION

The change to secondary treatment did not show better efficacy compared to PMC in children with macrolide-unresponsive MP pneumonia. Further studies are needed to guide appropriate treatment in children with MP pneumonia.

Low-dose versus high-dose methylprednisolone for children with severe Mycoplasma pneumoniae pneumonia (MCMP): Study protocol for a randomized controlled trial

BACKGROUND

Severe Mycoplasma pneumoniae pneumonia (MPP) may develop with long-term pulmonary outcomes despite treatment with macrolides. Combined treatment with glucocorticoids can improve this outcome, though the optimal dosage is unknown. The aim of this study was to investigate the effects of low- and high-dose methylprednisolone in reducing the percentage of long-term pulmonary outcomes for children with severe MPP.

METHODS

A randomized, single-blind, parallel-controlled, multicenter clinical trial, methylprednisolone for children with severe M. pneumoniae pneumonia (MCMP), is being conducted in China. Pediatric patients (≤18 years of age, expected number = 402) admitted to the hospital with a clinical diagnosis of severe MPP and fulfilling inclusion and exclusion criteria are randomized (ratio of 1:1) to either a low-dose (2 mg/kg/d) or high-dose (10 mg/kg/d) methylprednisolone treatment group for 3 days followed by tapering of methylprednisolone over 12 days and combined with azithromycin. The primary composite outcome will be incidence of atelectasis, bronchiectasis, or bronchiolitis obliterans at 6-months after treatment. Secondary outcomes include recovery time of patient temperature, proportion of pulmonary lesions absorbed, changes of mucosa identified by bronchoscopy, length of hospital stay, pulmonary function and number of participant(s) needing intensive care. Assessments will be made at baseline, post-treatment and at 1-month, 3-month and 6-month follow-ups.

DISCUSSION

This is the first randomized clinical trial designed to evaluate the safety and efficacy of low- versus high-dose methylprednisolone for reducing long-term pulmonary outcomes in pediatric patients with severe MPP. The results of this study will provide scientific evidence to guide clinical practice for the treatment of severe MPP. Trial registration: This study is registered at ClinicalTrials.gov (NCT02303587).

Increased procalcitonin level is a risk factor for prolonged fever in children with Mycoplasma pneumonia

PURPOSE

Macrolide-resistant Mycoplasma pneumoniae pneumonia (MPP) is characterized by prolonged fever and radiological progression despite macrolide treatment. Few studies have examined serum procalcitonin (PCT) level in children with MPP. We aimed to investigate the association of acute inflammation markers including PCT with clinical parameters in children with MPP.

METHODS

A total of 147 children were recruited. The diagnosis of MPP relied on serial measurement of IgM antibody against mycoplasma and/or polymerase chain reaction. We evaluated the relationships between C-reactive protein (CRP), PCT, and lactate dehydrogenase (LDH) levels and white blood cell (WBC) counts, and clinical severity of the disease. We used multivariate logistic regression analysis to estimate the odds ratio for prolonged fever (>3 days after admission) and hospital stay (> 6 days), comparing quintiles 2-5 of the PCT levels with the lowest quintile.

RESULTS

The serum PCT and CRP levels were higher in children with fever and hospital stay than in those with fever lasting ≤ 3 days after admission and hospital stay ≤ 6 days. CRP level was higher in segmental/lobar pneumonia than in bronchopneumonia. The LDH level and WBC counts were higher in children with fever lasting for >3 days before compared to those with fever lasting for ≤ 3 days. The highest quintile of PCT levels was associated with a significantly higher risk of prolonged fever and/or hospital stay than the lowest quintile.

CONCLUSION

Serum PCT and CRP levels on admission day were associated with persistent fever and longer hospitalization in children with MPP.

Evaluation of the illumigene Mycoplasma Direct DNA Amplification Assay

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia. The illumigene Mycoplasma Direct (iMD) DNA amplification assay is a qualitative in vitro test utilizing loop-mediated isothermal amplification (LAMP) technology for the direct detection of M. pneumoniae DNA in respiratory specimens. The iMD assay does not require the preextraction of nucleic acids from specimens, which is a prerequisite step for the previously approved illumigene Mycoplasma (iM) assay. The aim of this prospective multicenter study was to evaluate the performance characteristics of the newly developed iMD assay, compared with the iM assay. Subjects with symptoms of upper respiratory illnesses suggesting M. pneumoniae infection were enrolled at three sites in the United States. Respiratory specimens were obtained using dual throat swabs. One swab was tested with the iMD assay at each enrollment site. Reference testing with the iM assay was performed by the manufacturer. Among 456 specimens tested, the iM reference method detected M. pneumoniae in 25 specimens (5.5%), while the iMD assay identified 34 specimens (7.5%) as M. pneumoniae positive. There were 10 false-positive results and 1 false-negative result with the iMD assay. The overall positive and negative agreement rates were 96.0% (95% confidence interval [CI], 80.5 to 99.3%) and 97.7% (95% CI, 95.8 to 98.7%), respectively. The overall agreement rate was determined to be 97.6% (95% CI, 95.7 to 98.6%). We conclude that the iMD test results were comparable to the iM assay results. The removal of the DNA extraction step for the iMD assay simplifies testing, saves time, and reduces the costs of detecting M. pneumoniae from throat swabs, compared to the iM assay.

Comparison of chemiluminescence immunoassay, enzyme-linked immunosorbent assay and passive agglutination for diagnosis of Mycoplasma pneumoniae infection

Objective

This study aimed to compare the performance of chemiluminescence immunoassay (CLIA), enzyme-linked immunosorbent assay (ELISA), and passive agglutination (PA) method in detecting Mycoplasma pneumoniae (MP) infection.

Methods

This study enrolled a total of 280 patients who were consecutively seen at the Nanfang Hospital of the Southern Medical University in Guangdong Province, China, between August and December 2016. Serum was collected and examined by CLIA, ELISA, and PA, respectively.

Results

There were 180 positive (64.3%) and 100 negative cases (35.7%) by PA, 184 positive (65.7%) and 96 negative cases (34.3%) by CLIA MP-immunoglobulin (Ig) M, 89 positive (31.8%) and 191 negative cases (68.2%) by CLIA MP-IgG, 196 positive (70%) and 84 negative cases (30%) by ELISA MP-IgM, and 114 positive (40.7%) and 166 negative cases (59.3%) by ELISA MP-IgG. Patients were allocated to two groups based on PA results. In PA-negative group (≤1:40), the positive rates of MP-IgM by CLIA were 22.8% and 51.2% and by ELISA were 33.3% and 53.5%, respectively. In the PA-positive group (1:80 to ≥1:1,280), MP-IgM negative cases showed a decreasing trend: 40%, 18%, 14.3%, 10%, and 6.7% (CLIA), and 43.3%, 8%, 14.3%, 5%, and 6.7% (ELISA). The consistency between CLIA/ELISA MP-IgM, -IgG, and -IgG+MP-IgM was >92% for negative cases and >75% for positive cases, resulting in an overall consistency rate >88%. The kappa coefficients were 0.804, 0.763, and 0.806, respectively.

Conclusion

CLIA and ELISA have a higher sensitivity compared with PA. CLIA has a high concordance with ELISA. Moreover, CLIA has a higher specificity and sensitivity for the detection of IgM and IgG and should be used for the clinical diagnosis of MP infection.

Mycoplasma pneumoniae: A Potentially Severe Infection

Mycoplasma pneumoniae infections remain one of the most common etiologies of community-acquired pneumonia (CAP). The clinical presentation and manifestations vary widely and can affect all organs of the body. Diagnosis is challenging because there are no constant findings in physical exams or laboratory or radiological assessments that indicate Mycoplasma pneumoniae pneumonia, and specific diagnostic tools are not readily available. Extrapulmonary manifestations and severe pulmonary manifestations can lead to long-term sequelae. The increasing emergence of Mycoplasma pneumoniae that is resistant to macrolides in some areas of the world and increased world travel could add to the difficulty of controlling and treating Mycoplasma pneumoniae infections. We present a concise and up-to-date review of the current knowledge of Mycoplasma pneumoniae pneumonia.

ATF3 inhibits the inflammation induced by Mycoplasma pneumonia in vitro and in vivo

OBJECTIVES

Activating transcription factor-3 (ATF3) is a key regulator of inflammatory responses. We aimed to investigate the effects and mechanisms of ATF3 on the inflammatory cytokines are induced by Mycoplasma pneumonia (MP).

STUDY DESIGN

RAW264.7 and mouse peritoneal macrophages were exposed to various time with or without MP infection (3, 6, 12, 24, and 48 h), and detect the expression of ATF3. Adenovirus-expression of ATF3 (Ad/ATF3) or Ad/βgal was transfected into cells which were exposed to MP for 48 h, RT-PCR and ELISA was used to evaluate the expression and secretion of TNF-α, IL-1β, IL-6, and IL-18. In addition, intravenous administration Ad/ATF3 or Ad/βgal into the mice, the secretion of inflammatory cytokines were detected using ELISA. ChIP assay was used to determine whether ATF3 can bind to the promoter of Early growth response protein 1 (Egr-1). Western blot was used to detect the expression of Egr-1 and Fyn.

RESULTS

ATF3 was increased at 3, 6, 12, and 24 h and the highest expression levels occurs in 6 h, there is no significant differences at 24 and 48 h compared with 0 h or CON group in RAW 264.7. Similar results were seen in mouse peritoneal macrophages. Overexpression of ATF3 resulted in the reduction of inflammatory cytokines. ChIP assay revealed that ATF3 can bind to the promoter of Egr-1. Overexpression of ATF3 inhibited the protein expression of Egr-1 and Fyn; conversely, ATF3-deficiency promoted the expression of Egr-1 and Fyn. Overexpression of Egr-1 reduced the anti-inflammatory action of ATF3.

CONCLUSIONS

ATF3 inhibit the expression and release of TNF-α, IL-1β, IL-6, and IL-18 induced by MP in vitro and in vivo, which is associated with its negative regulation of Egr-1/Fyn signaling pathway.

Effects of methylprednisolone or immunoglobulin when added to standard treatment with intravenous azithromycin for refractory Mycoplasma pneumoniae pneumonia in children

BACKGROUND

The prevalence of Mycoplasma pneumoniae pneumonia has increased considerably in recent years. To evaluate the efficacy of combined treatment of azithromycin with intravenous immunoglo-bulin (IVIG) or methylprednisolone in children with refractory Mycoplasma pneumoniae pneumonia (RMPP).

METHODS

Children with RMPP were randomly allocated to group A [intravenous azithromycin (IA)+ methylprednisolone], group B (IA+IVIG) or group C (IA alone). Following a 7-day treatment, group C patients were randomly separated into two sub-groups: group C₁ (IA+methylprednisolone) and group C₂ (IA+IVIG). Temperature, respiratory symptoms and signs were examined. The average febrile period after treatment (F₂), average total febrile period (F₃), infiltration absorption, atelectasis resolution, pleural effusion disappearance were determined. The levels of C-reactive protein (CRP), D-dimer, and lactate dehydrogenase (LDH) were measured.

RESULTS

Seven days after enrollment, the average F₂ after treatment of group A was the shortest. Compared with the control group C, the combined treatment group A and B showed higher rates of infiltration absorption, atelectasis resolution and pleural effusion disappearance, while lower levels of serum CRP, D-dimer and LDH. Fourteen days after enrollment, all children with combined therapy clinically improved, and presented better laboratory results. Group C₁ showed shorter F₃ and lower levels of CRP and LDH than those of group C₂. Overall, group A showed the shortest F₃, also has the lowest CRP and LDH.

CONCLUSIONS

Azithromycin with IVIG or methylprednisolone was better treatment for children with RMPP than azithromycin alone. IVIG treatment may be beneficial, especially when the efficacy of corticosteroids is insecure, thus could be considered as an alternative of primary therapeutic approaches.

A unified pathogenesis for kidney diseases, including genetic diseases and cancers, by the protein-homeostasis-system hypothesis

Every cell of an organism is separated and protected by a cell membrane. It is proposed that harmony between intercellular communication and the health of an organism is controlled by a system, designated the protein-homeostasis-system (PHS). Kidneys consist of a variety of types of renal cells, each with its own characteristic cell-receptor interactions and producing characteristic proteins. A functional union of these renal cells can be determined by various renal function tests, and harmonious intercellular communication is essential for the healthy state of the host. Injury to a kind of renal cells can impair renal function and induce an imbalance in total body health. Every acute or chronic renal disease has unknown etiologic substances that are responsible for renal cell injury at the molecular level. The immune/repair system of the host should control the etiologic substances acting against renal cells; if this system fails, the disease progresses to end stage renal disease. Each renal disease has its characteristic pathologic lesions where immune cells and immune proteins, such as immunoglobulins and complements, are infiltrated. These immune cells and immune proteins may control the etiologic substances involved in renal pathologic lesions. Also, genetic renal diseases and cancers may originate from a protein deficiency or malfunctioning protein under the PHS. A unified pathogenesis for renal diseases, including acute glomerulonephritis, idiopathic nephrotic syndrome, immunoglobulin A nephropathy, genetic renal diseases such as Alport syndrome, and malignancies such as Wilms tumor and renal cell carcinoma, is proposed using the PHS hypothesis.

Mechanism of resistance acquisition and treatment of macrolide-resistant Mycoplasma pneumoniae pneumonia in children

Mycoplasma pneumoniae pneumonia (MPP) is one of the most common forms of community-acquired pneumonia in children and adolescents. Outbreaks of MPP occur in 3- to 7-year cycles worldwide; recent epidemics in Korea occurred in 2006–2007, 2011, and 2015–2016. Although MPP is known to be a mild, self-limiting disease with a good response to macrolides, it can also progress into a severe and fulminant disease. Notably, since 2000, the prevalence of macrolide-resistant MPP has rapidly increased, especially in Asian countries, recently reaching up to 80%–90%. Macrolide-resistant Mycoplasma pneumoniae (MRMP) harbors a point mutation in domain V of 23S rRNA with substitutions mainly detected at positions 2063 and 2064 of the sequence. The excessive use of macrolides may contribute to these mutations. MRMP can lead to clinically refractory pneumonia, showing no clinical or radiological response to macrolides, and can progress to severe and complicated pneumonia. Refractory MPP is characterized by an excessive immune response against the pathogen as well as direct injury caused by an increasing bacterial load. A change of antibiotics is recommended to reduce the bacterial load. Tetracyclines or quinolones can be alternatives for treating MRMP. Otherwise, corticosteroid or intravenous immunoglobulin can be added to the treatment regimen as immunomodulators to down-regulate an excessive host immune reaction and alleviate immune-mediated pulmonary injury. However, the exact starting time point, dose, or duration of immunomodulators has not been established. This review focuses on the mechanism of resistance acquisition and treatment options for MRMP pneumonia.

Pneumonia, Acute Respiratory Distress Syndrome, and Early Immune-Modulator Therapy

Acute respiratory distress syndrome (ARDS) is caused by infectious insults, such as pneumonia from various pathogens or related to other noninfectious events. Clinical and histopathologic characteristics are similar across severely affected patients, suggesting that a common mode of immune reaction may be involved in the immunopathogenesis of ARDS. There may be etiologic substances that have an affinity for respiratory cells and induce lung cell injury in cases of ARDS. These substances originate not only from pathogens, but also from injured host cells. At the molecular level, these substances have various sizes and biochemical characteristics, classifying them as protein substances and non-protein substances. Immune cells and immune proteins may recognize and act on these substances, including pathogenic proteins and peptides, depending upon the size and biochemical properties of the substances (this theory is known as the protein-homeostasis-system hypothesis). The severity or chronicity of ARDS depends on the amount of etiologic substances with corresponding immune reactions, the duration of the appearance of specific immune cells, or the repertoire of specific immune cells that control the substances. Therefore, treatment with early systemic immune modulators (corticosteroids and/or intravenous immunoglobulin) as soon as possible may reduce aberrant immune responses in the potential stage of ARDS.