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

The Mechanism of Baicalin in the Treatment of Mycoplasma Pneumoniae Pneumonia by Regulating NLRP3/Caspase-1 Signaling Pathway

OBJECTIVE

This study investigated the mechanism of baicalin (BIA) attenuating the inflammatory response and lung injury in mycoplasma pneumoniae pneumonia (MPP) mice.

METHODS

MPP mouse models were established and then treated with BIA, azithromycin, or NLRP3 inflammasome activator. Lung wet-to-dry weight (W/D) ratio were weighed. Serum levels of MP-IgM, C-reactive protein (CRP) and bronchoalveolar lavage fluid (BALF) protein were detected by kits, NLRP3/Caspase-1 pathway-related protein levels by Western blot, and IL-1β, IL-18, IL-6 and TNF-α levels by ELISA. HE staining was performed to detect lung injury.

RESULTS

MPP mice showed elevated mouse lung W/D ratio, upregulated serum MP-IgM and CRP levels and BALF protein, and enhanced IL-6 and TNF-α levels, which were reversed by BIA or azithromycin treatment, suggesting that BIA attenuated pulmonary inflammatory response in MPP mice. The lung tissue of MPP mice showed upregulated NLRP3, cleaved Caspase-1,Caspase-1, GSDMD-N and GSDMD levels and raised IL-1β and IL-18 levels, and changes were annulled by BIA or azithromycin treatment, suggesting that BIA inhibited the NLRP3/Caspase-1 pathway activation. NLRP3/Caspase-1 pathway activation partially abrogated the alleviative effect of BIA on the pulmonary inflammatory response of MPP mice.

CONCLUSION

BIA mitigates inflammatory response and lung injury in MPP mice by inhibiting NLRP3/Caspase-1 pathway activation.

Global prevalence, resistance rates, and underlying resistance mechanisms of clinical Mycoplasma and Ureaplasma species

Mycoplasmas are significant pathogens in human health, implicated in a range of clinical conditions from respiratory infections to urogenital disorders. Their resistance to commonly used antibiotics poses a substantial challenge to treatment and control. This study aims to provide a comprehensive overview of the global distribution of clinical mycoplasmas, elucidate their resistance to various antibiotics, and identify the genetic and molecular mechanisms underlying their resistance. A systematic review and meta-analysis were conducted, collating data from peer-reviewed publications between 2012 and 2024. The UK (100%) and Germany (98%) reported high numbers of respiratory mycoplasmas, with 7% and 2% being resistant to macrolides. For urogenital mycoplasmas, Iceland (99%) and Estonia (94%) reported a high prevalence of Mycoplasma species, whereas the UK (85%), France (82%), and the USA (82%) reported a high prevalence of Ureaplasma species. High resistance rates in Mycoplasma and Ureaplasma have been reported in Greenland (100%) and the UK (86%), respectively. The rising resistance rates in these species underscore an urgent need for updated treatment guidelines and the development of novel therapeutic options. Our findings highlight the importance of tailored antibiotic stewardship and the potential of genomic insights in guiding effective treatment strategies.

Clinical characteristics and predictive indictors of macrolide-unresponsive Mycoplasma pneumoniae pneumonia in children: a retrospective study

Introduction

Macrolide-unresponsive Mycoplasma pneumoniae pneumonia (MUMPP) cases have been rapidly increasing. The primary reason for this increased incidence is the pathogen's acquisition of resistance through mutations in 23S rRNA genes. Due to the unfeasibility of testing for macrolide susceptibility at the time of admission, this study aimed to assess the clinical features of pediatric MUMPP, using insights from laboratory tests and patterns of chest radiographic resolution.

Material and methods

We conducted a retrospective review of 161 patients with M. pneumoniae pneumonia (MPP) between January 2023 and December 2023. These patients were categorized into two groups based on their responsiveness to macrolides: 72 patients were in the MUMPP group, and 89 patients were in the macrolide-sensitive Mycoplasma pneumoniae pneumonia (MSMP) group.

Results

MUMPP patients experienced a longer duration of fever and hospital stay. A higher proportion of MUMPP patients had shortness of breath, transcutaneous blood oxygen saturation (SpO2) lower than 94%, bilateral lobar infiltrates, lobar pneumonia and pleural effusion. The serum level of serum ferritin (SF), interleukin-6(IL-6), D-dimer, lactate dehydrogenase to albumin rate (LAR), and neutrophil to lymphocyte rate (NLR) were higher in MUMPP group.

Conclusions

Our findings revealed that patients with MUMPP exhibit more severe initial radiographic indicators and clinical course compared to those with MSMP. Therefore, it is crucial to promptly administer alternative therapeutic agents besides macrolides for the management of MUMPP.

Efficacy of azithromycin combined with intravenous immunoglobulin in the treatment of refractory mycoplasma pneumoniae pneumonia in children: a meta-analysis

BACKGROUND

The incidence of refractory Mycoplasma pneumoniae pneumonia (RMPP) in children is increasing, posing a serious threat to life safety. Intravenous immunoglobulin (IVIG) has demonstrated the ability to modulate the immune system and has shown the potential to treat RMPP. This study evaluated the clinical efficacy and safety of azithromycin combined with IVIG in the treatment of RMPP in children through a meta-analysis.

METHODS

A comprehensive search was conducted in seven databases including PubMed and Cochrane Library, and the studies on the treatment of RMPP in children with azithromycin combined with IVIG were screened. After data extraction, meta-analysis and sensitivity analysis were performed to assess heterogeneity and stability.

RESULTS

Thirteen randomized controlled trials and two cohort studies were included, totaling 1,142 children. The results of meta-analysis showed a higher clinical efficacy rate (RR = 1.18, 95% CI: 1.11-1.25, P < 0.01) and shorter time to defervescence (MD = -2.12, 95% CI: -2.69--1.55), time to disappearance of pulmonary rales (MD = -2.90, 95% CI: -3.57--2.23), time to disappearance of cough (MD = -3.59, 95% CI: -4.51--2.67), and hospital length of stay (MD = -5.72, 95% CI: -8.80--2.64) in the experimental group receiving azithromycin combined with IVIG treatment compared to the control group treated with azithromycin alone. Additionally, there was no significant publication bias in this meta-analysis.

CONCLUSION

Treatment with azithromycin combined with IVIG is more effective than treatment with azithromycin alone for children with RMPP.

CLINICAL TRIAL NUMBER

Not applicable.

New Insights into the Epidemiological Characteristics of Mycoplasma pneumoniae Infection before and after the COVID-19 Pandemic

Mycoplasma pneumoniae (M. pneumoniae), a prevalent respiratory pathogen affecting children and adolescents, is known to trigger periodic global epidemics. The most recent significant outbreak commenced in the first half of 2023 and reached its peak globally during the autumn and winter months. Considering the worldwide repercussions of the COVID-19 pandemic, it has become increasingly essential to delve into the epidemiological characteristics of M. pneumoniae both before and after the pandemic. This review aims to provide a comprehensive analysis of the key features of M. pneumoniae epidemics in the pre-and post-COVID-19 contexts, including but not limited to shifts in the susceptible population, the molecular genotypes of the pathogen, the clinical manifestations, and potential new trends in drug resistance. Additionally, we will introduce the latest advancements in the diagnosis of M. pneumoniae.

Construction of a predictive model of respiratory endoscopic intervention in children with lobar pneumonia caused by Mycoplasma pneumoniae infection

Background

This study aimed to analyze the clinical features of children with lobar pneumonia caused by Mycoplasma pneumoniae (MP) infection, to explore the independent risk factors for bronchoscopic intervention in children with lobar pneumonia caused by MP infection. There is a lack of objective assessment tools to guide the use of bronchoscopy in clinical practice. For children with lobar pneumonia caused by MP infection, whether line shall be actively bronchoscope intervention therapy remains to be further defined. We also aimed to construct an early warning model of bronchoscopic intervention to provide an objective evaluation tool for clinicians.

Methods

We collected the clinical data of 533 children with lobar pneumonia caused by MP infection. The patients were divided into three groups according to the interventional indications for bronchoscopy and whether they were treated with bronchoscopic intervention, and the clinical features and prognosis of the three groups were compared. A binary logistic regression analysis was performed on the indicators with a significance value of P<0.05, which we retrieved from the comparative analysis between the first two groups to uncover the independent risk factors and regression equations concerning bronchoscopic intervention. The regression coefficient (β) of our regression model was then used to score related values in the model to construct a predictive scoring model of bronchoscopic intervention for the treatment of children with lobar pneumonia caused by MP infection.

Results

Children with lobar pneumonia caused by MP infection who demonstrated absolute indications for bronchoscopy exhibited more severe clinical manifestations, and children without absolute indications for bronchoscopy had a better prognosis even without bronchoscopic intervention. To establish our early warning model of bronchoscopic intervention for children with lobar pneumonia caused by MP infection, we used the following indices: C-reactive protein ≥20.94 mg/L (β1=2.253) received 3 points, while a fever duration before bronchoscopy ≥6.5 d (β2=1.424), lactate dehydrogenase ≥461.5 U/L (β3=1.246), or fever (β4=1.223) each received 2 points, and the complication of pleural effusion (β5=0.841) received 1 point, for a total possible score of 10 points.

Conclusions

When the score for the children with lobar pneumonia caused by MP infection was ≥6, the possibility of bronchoscopic intervention for treatment was >80%. The higher the score, the greater the possibility of bronchoscopic intervention.

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.

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.

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.

Clinical features and risk factors of plastic bronchitis caused by refractory Mycoplasma pneumoniae pneumonia in children: a practical nomogram prediction model

Early assessment of refractory Mycoplasma pneumoniae pneumonia (RMPP) with plastic bronchitis (PB) allows timely removal of casts using fiberoptic bronchoscopic manipulation, which relieves airway obstruction and limit sequelae development. This study aimed to analyze clinical data for risk factors and develop a nomogram for early predictive evaluation of RMPP with PB. The clinical data of 1-14 year-old patients with RMPP were retrospectively analyzed. Patients were classified into a PB or non-PB group. The general characteristics, clinical symptoms, laboratory test results, imaging findings, and microscopic changes of the two groups were compared. A statistical analysis of the risk factors for developing PB was performed, and a nomogram model of risk factors was constructed. Of 120 patients with RMPP included, 68 and 52 were in the non-PB and PB groups, respectively. Using multivariate logistic regression analysis, fever before bronchoscopy, extrapulmonary complications, pleural effusion, cough duration, and lactate dehydrogenase (LDH) levels were identified as risk factors. A nomogram was constructed based on the results of the multivariate analysis. The area under the receiver operating characteristic curve value of the nomogram was 0.944 (95% confidence interval: 0.779-0.962). The Hosmer-Lemeshow test displayed good calibration of the nomogram (p = 0.376, R2 = 0.723).

CONCLUSION

The nomogram model constructed in this study based on five risk factors (persistent fever before bronchoscopy, extrapulmonary complications, pleural effusion, cough duration, and LDH levels) prior to bronchoscopy can be used for the early identification of RMPP-induced PB.

WHAT IS KNOWN

• Refractory Mycoplasma pneumoniae pneumonia (RMPP) in children has been increasingly reported and recognized, which often leads to serious complications. • Plastic bronchitis (PB) is considered to be one of the causes of RMPP, and bronchoscopic treatment should be improved as soon as possible to remove plastic sputum thrombus in bronchus.

WHAT IS NEW

• This study determined the risk factors for RMPP-induced PB. • The nomogram model constructed in this study prior to bronchoscopy can be used for the early identification of RMPP-induced PB, which facilitate the early bronchoscopic removal of casts, thereby promoting recovery and reducing cases with poor RMPP prognosis.

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.

Efficacy of Gamma Globulin Combined with Azithromycin Sequential Therapy in the Treatment of RMPP and Its Effect on Th1/Th2 Cytokine Levels

Objective

To investigate the efficacy of gamma globulin combined with azithromycin sequential therapy in the treatment of children with refractory mycoplasma pneumonia and its effect on Th1/Th2 cytokine levels.

Method

From January 2021 to January 2022, 100 children diagnosed with refractory mycoplasma pneumonia were randomly divided into 2 groups (50 cases in each one), the control group was treated with azithromycin plus comprehensive basic treatment, and the treatment group was treated with combined treatment on the basis of the control group, gamma globulin therapy; the treatment effect and cytokine levels of the two groups were compared.

Results

Th1, Th2, and Th1/Th2 before treatment were not significantly different between the two groups. Th1, Th2, and Th1/Th2 in the treatment group were significantly downregulated compared with those in the control group after treatment. The levels of IgG, IgA, and IgM in the treatment group were not significantly different from those in the control group before treatment but were significantly upregulated after treatment. IL-10, IL-6, and IL-2 levels were also significantly increased in the treatment group. The disappearance time of clinical symptoms such as fever, cough, and pulmonary rales in the treatment group was significantly shorter than that in the control group, and the cure rate in the treatment group was significantly better than that in the control group.

Conclusion

The clinical effect of gamma globulin combined with azithromycin sequential therapy in the treatment of children with refractory mycoplasma pneumonia is remarkable, which can reduce inflammatory factors, improve patients' immunity, and promote disease recovery.

A Study Based on Metabolomics, Network Pharmacology, and Experimental Verification to Explore the Mechanism of Qinbaiqingfei Concentrated Pills in the treatment of Mycoplasma Pneumonia

Qinbaiqingfei concentrated pills (QB) are a commonly used medicine for the treatment of mycoplasma pneumonia in China, and the mechanism of action of QB needs to be studied further. Therefore, we use a combination of metabolomics and network pharmacology to clarify the mechanism of QB. Nontarget metabolomics studies were performed on rat serum, urine, and lung tissues, and 56 therapeutic biomarkers were found. Subsequently, the components of QB absorbed into the blood and lung tissues were clarified, and based on this finding, the core target of network pharmacology was predicted. The enrichment analysis of biomarkers–genes finally confirmed their close relationship with the NF-κB signaling pathway. By western blotting expression of the proteins in the lung tissue–related signaling pathways, it is finally confirmed that QB inhibits the NF-κB signaling pathway through SIRT1, IL-10 and MMP9, CTNNB1, EGFR, and other targets. It plays a role in regulating immunity, regulating metabolism, and treating diseases.

Effects of minocycline on macrolide-unresponsive Mycoplasma pneumoniae pneumonia in children: a single-center retrospective study

BACKGROUND

Macrolide-resistant Mycoplasma pneumoniae (Mp) has become widespread in the world. We sought to determine the independently associated risk factors for refractory Mp pneumonia among macrolide-unresponsive Mp pneumonia children treated with minocycline and to investigate the effects of minocycline against macrolide-unresponsive Mp pneumonia.

METHODS

In our center, we retrospectively analyzed the data of hospitalized macrolide-unresponsive Mp pneumonia patients aged ≤18 years old who changed macrolide therapies to minocycline treatments between March 2013 and September 2018. Patient characteristics and defervescence after minocycline treatment were compared between refractory Mp pneumonia and non-refractory Mp pneumonia groups. Multivariable logistic regression analysis was performed among these macrolide-unresponsive Mp pneumonia patients.

RESULTS

Among 150 included macrolide-unresponsive Mp pneumonia children treated with minocycline; 30 cases (20.0%) were refractory Mp pneumonia. Duration of macrolide treatment before administration of minocycline (odds ratio =2.87, 95% CI: 1.79-4.61, P<0.001) and serum procalcitonin levels (odds ratio =13.50, 95% CI: 1.22-149.57, P=0.034) were independently associated with refractory Mp pneumonia. Defervescence after minocycline treatment was significantly longer among the refractory Mp pneumonia group than in the non-refractory Mp pneumonia group (median 2 vs. 1 day, P<0.001). Only one case (0.7%) suspected of a side effect of minocycline therapy was observed.

CONCLUSIONS

Two risk factors independently associated with refractory Mp pneumonia were determined. Early use of minocycline might safely prevent macrolide-unresponsive Mp pneumonia from progressing to refractory Mp pneumonia.

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.

Consideration in treatment decisions for refractory Mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae (MP) is the most common cause of childhood bacterial pneumonia. Although macrolide is known to be effective as a first-line therapy, the proportion of macrolide resistance in MP pneumonia has strikingly increased during recent 2 decades in East Asia. This is challenging to physicians since they have to decide more often whether to use secondary treatment. Diagnostic methods to detect macrolide-resistance of MP are currently not available in Korean hospitals. Even in the diagnosis of MP infection, both serologic and molecular test have limitation: inability to differentiate current illness from carriage or asymptomatic infection. Combining these 2 diagnostic methods and excluding infection caused by other respiratory pathogens allow a more reliable diagnosis. This effort is even more demanding in recent years to keep children from unnecessary exposure to secondary antibiotics. Although several observational studies have reported that tetracycline and fluoroquinolone, which are considered in the treatment of refractory MP pneumonia, have efficacy of shortening the duration of fever and respiratory symptoms, those findings need to be proven by well-designed prospective studies. The use of tetracycline and fluoroquinolone in children is generally tolerable, as supported by many observational data. However, since concerns about side effects still remain, careful consideration about benefits and risks is needed to decide their use.

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

Background

Mycoplasma pneumoniae (MP) pneumonia in children can be challenging to treat, and the impact of MP blood infection is unclear. The present study aims to determine the prevalence and clinical characteristics of MP septicemia among pediatric patients.

Methods

Children hospitalized at our center for MP pneumonia between October 2017 and June 2018 were included. Healthy controls visiting our outpatient clinic for regular physical examinations were also enrolled. MP was detected by real-time polymerase chain reaction (qPCR) analysis of plasma and peripheral blood mononuclear cell (PBMC) samples.

Results

Sixty-one children with MP pneumonia and 30 healthy children were included. Among children with MP infection, 31 (50.8%) were positive for MP by qPCR (19 in plasma samples, 8 in PBMC samples, and 4 in both). All healthy controls were negative for MP by qPCR.

Conclusions

The prevalence of MP septicemia in children with MP pneumonia is moderate. However, detection of MP in blood samples may have limited clinical value for guiding treatment.

Chinese Herbal Medicine for the Treatment of Children and Adolescents With Refractory Mycoplasma Pneumoniae Pneumonia: A Systematic Review and a Meta-Analysis

Objectives: Chinese herb medicine (CHM) is one of the most popular complementary and alternative therapies, which has been widely used to treat Refractory Mycoplasma Pneumoniae Pneumonia (RMPP). However, the effect and safety of CHM remain controversial. Hence, we conducted this meta-analysis to evaluate whether CHM combination therapy could bring benefits to children and adolescents with RMPP. Methods: Seven databases were used for data searching through November 11, 2020 following the PRISMA checklist generally. Review Manager 5.3, Trial sequential analysis 0.9.5.10 Beta software and Stata16.0 were applied to perform data analyses. Mean difference or risk ratio was adopted to express the results, where a 95% confidence interval (CI) was applied. Results: In general, this research enrolled 17 trials with 1,451 participants. The overall pooled results indicated that CHM was beneficial for children and adolescents with RMPP by improving the clinical efficacy rate [RR = 1.20, 95% CI (1.15, 1.25), p < 0.00001], shortening antipyretic time [MD = -2.60, 95% CI (-3.06, -2.13), p < 0.00001], cough disappearance time [MD = -2.77, 95% CI (-3.12, -2.42), p < 0.00001], lung rale disappearance time [MD = -2.65, 95% CI (-3.15, -2.15), p < 0.00001], lung X-ray infiltrates disappearance time [MD = -2.75, 95% CI (-3.33, -2.17), p < 0.00001], reducing TNF-α level [MD = -5.49, 95% CI (-7.21, -3.77), p < 0.00001]. Moreover, subgroup results suggested that removing heat-phlegm and toxicity therapy had more advantages in shortening antipyretic time, cough disappearance time, lung X-ray infiltrates disappearance time and reducing TNF-α level. Meanwhile promoting blood circulation therapy seemed to be better at relieving lung rale. However, regarding adverse events, the two groups displayed no statistical difference [RR = 0.97, 95% CI (0.60, 1.57), p = 0.91]. Conclusion: Despite of the apparently positive results in relieving clinical symptoms, physical signs and reducing inflammation, it is premature to confirm the efficacy of CHM in treating RMPP because of the limitation of quality and the number of the included studies. More large-scale, double-blind, well-designed, randomized controlled trials are needed in future research.

Mutations in domain V of Mycoplasma pneumoniae 23S rRNA and clinical characteristics of pediatric M. pneumoniae pneumonia in Nanjing, China

OBJECTIVE

To investigate the prevalence of mutations in domain V of Mycoplasma pneumoniae (MP) 23S ribosomal RNA (rRNA) and the clinical characteristics of pediatric MP pneumonia (MPP) in Nanjing, China.

METHODS

Domain V of 23S rRNA was sequenced in MP strains collected from children diagnosed with MPP in Nanjing. Clinical and laboratory data were obtained.

RESULTS

Among the 276 MP strains, 255 (92.39%) harbored mutations, primarily A2063G in domain V of MP 23S rRNA. When children were stratified according to the presence or absence of mutations, no significant differences were found in sex, age, the MP DNA load at enrollment, lymphocyte counts, pulmonary complications, immunomodulator levels, fever duration, the duration of fever after macrolide therapy, and hospital stay. The prevalence of refractory MPP in the two groups was similar. Children with refractory MPP exhibited higher MP DNA loads than those with non-refractory MPP.

CONCLUSIONS

Despite the high prevalence of the A2063G mutation in domain V of MP 23S rRNA, mutations were not associated with the clinical characteristics of MPP. The MP DNA load significantly differed between refractory and non-refractory MPP.

Highly homogeneous microbial communities dominated by Mycoplasma pneumoniae instead of increased resistance to macrolide antibiotics is the characteristic of lower respiratory tract microbiome of children with refractory Mycoplasma pneumoniae pneumonia

BACKGROUND

Although researchers have found that the microbiota changed during the lower respiratory tract (LRT) infection, little was known about the association between LRT microbiome and refractory M. pneumoniae pneumonia (RMPP).

METHODS

From June 28th, 2019 to March 23rd, 2020, we enrolled fifty-two children diagnosed with RMPP or non-refractory M. pneumoniae pneumonia (NRMPP), and characterized the structure and function of microbiota in the bronchoalveolar lavage fluid (BALF) by metagenomic next generation sequencing (mNGS).

RESULTS

Based on Bray-Curtis distance between samples, samples in RMPP group were highly homogeneous, and Shannon index in the RMPP group was much lower than NRMPP group while Simpson index, which presents the degree of dominance, was higher in RMPP group. The dominant taxon with relative abundance greater than 50% was merely Mycoplasma among RMPP and NRMPP patients, but the proportions of other taxonomic distribution were different. M. pneumoniae was the dominant species and occupied almost all niches in the vast majority of RMPP patients, whereas the other genera were dramatically lower. The NRMPP group was more enriched in antibiotic resistance genes (ARGs) than the RMPP group, and also exhibited a greater relative abundance of macrolide antibiotics resistance gene (macB) and fluoroquinolone antibiotic resistance genes (patA-B) in M. pneumoniae genome. In RMPP patients, higher relative abundance of Streptococcus pneumoniae had a strong correlation with increased hospitalization days while higher relative abundance of Streptococcus pneumoniae had a negative correlation with hospitalization days among NRMPP patients.

CONCLUSIONS

The microbiota of LRT in children with RMPP was much more homogeneous and simpler than that of the NRMPP group and with lower relative abundance of macrolide antibiotics resistance gene in M. pneumoniae genome. M. pneumoniae was absolutely dominant in the vast majority of RMPP patients. Prolonged hospitalization days was associated with relative abundance of M. pneumoniae in NRMPP patients while it was related with other pathogens' relative abundance (e.g., Streptococcus pneumoniae) in RMPP patients.

Comparison of different detection methods for Mycoplasma pneumoniae infection in children with community-acquired pneumonia

BACKGROUND

Due to the lack of a sensitive, specific and rapid detection method, aetiological diagnosis of pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae, MP) is a constantly challenging issue. This retrospective study aimed to compare the diagnostic methods for Mycoplasma pneumoniae in children and evaluate their values.

METHODS

From November 2018 to June 2019, 830 children with community-acquired pneumonia were selected from the Department of Respiratory Medicine, Shanghai Children's Medical Center. On the first day of hospitalization, sputum, throat swab and venous blood samples were collected to analyse MP-IgM (particle agglutination, PA), MP-IgM (immune colloidal gold technique, GICT), MP-DNA, MP-RNA (simultaneous amplification and testing, SAT) and MP-DNA (real-time polymerase chain reaction, RT-PCR).

RESULTS

Among these 830 children, RT-PCR showed that the positive rate was 36.6% (304/830), in which the positive rate of macrolide resistance (A2063G mutation) accounted for 86.2% of cases (262/304). Using RT-PCR as the standard, MP-RNA (SAT) had the highest specificity (97.5%), and MP-IgM (PA) had the highest sensitivity (74.0%) and Youden index (53.7%). If MP-RNA (SAT) was combined with MP-IgM (PA), its Kappa value (0.602), sensitivity (84.2%), specificity (78.7%) and Youden index (62.9%) were higher than those of single M. pneumoniae detection.

CONCLUSIONS

Our research indicated that a combination of MP-RNA (SAT) plus MP-IgM (PA) might lead to reliable results as an early diagnostic method for children with clinical manifestations of Mycoplasma pneumoniae pneumonia.

Quantitative proteomics analysis of Mycoplasma pneumoniae identifies potential macrolide resistance determinants

Mycoplasma pneumoniae is one of the leading causes of community-acquired pneumonia in children and adolescents. Because of the wide application of macrolides in clinical treatment, macrolide-resistant M. pneumoniae strains have become increasingly common worldwide. However, the molecular mechanisms underlying drug resistance in M. pneumoniae are poorly understood. In the present work, we analyzed the whole proteomes of macrolide-sensitive and macrolide-resistant strains of M. pneumoniae using a tandem mass tag-labeling quantitative proteomic technique, Data are available via ProteomeXchange with identifier PXD022220. In total, 165 differentially expressed proteins were identified, of which 80 were upregulated and 85 were downregulated in the drug-resistant strain compared with the sensitive strain. Functional analysis revealed that these proteins were predominantly involved in protein and peptide biosynthesis processes, the ribosome, and transmembrane transporter activity, which implicates them in the mechanism(s) of resistance of M. pneumoniae to macrolides. Our results provide new insights into drug resistance in M. pneumoniae and identify potential targets for further studies on resistance mechanisms in this bacterium.

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.

Current perspectives on atypical pneumonia in children

The major pathogens that cause atypical pneumonia are Mycoplasma pneumoniae, Chlamydophila pneumoniae, and Legionella pneumophila. Community-acquired pneumonia (CAP) caused by M. pneumoniae or C. pneumoniae is common in children and presents as a relatively mild and self-limiting disease. CAP due to L. pneumophila is very rare in children and progresses rapidly, with fatal outcomes if not treated early. M. pneumoniae, C. pneumoniae, and L. pneumophila have no cell walls; therefore, they do not respond to β-lactam antibiotics. Accordingly, macrolides, tetracyclines, and fluoroquinolones are the treatments of choice for atypical pneumonia. Macrolides are the first-line antibiotics used in children because of their low minimum inhibitory concentrations and high safety. The incidence of pneumonia caused by macrolide-resistant M. pneumoniae that harbors point mutations has been increasing since 2000, particularly in Korea, Japan, and China. The marked increase in macrolide-resistant M. pneumoniae pneumonia (MRMP) is partly attributed to the excessive use of macrolides. MRMP does not always lead to clinical nonresponsiveness to macrolides. Furthermore, severe complicated MRMP responds to corticosteroids without requiring a change in antibiotic. This implies that the hyper-inflammatory status of the host can induce clinically refractory pneumonia regardless of mutation. Empirical macrolide therapy in children with mild to moderate CAP, particularly during periods without M. pneumoniae epidemics, may not provide additional benefits over β-lactam monotherapy and can increase the risk of MRMP.

Ten-year trends and prevalence of asthma, allergic rhinitis, and atopic dermatitis among the Korean population, 2008-2017

BACKGROUND

Major questions remain regarding the age-stratified trends of allergic diseases and asthma in Korea.

PURPOSE

To identify the estimated recent prevalence and 10- year trends in asthma, allergic rhinitis, and atopic dermatitis among the Korean population from 2008 to 2017.

METHODS

This nationwide cross-sectional survey (Korean National Health and Nutrition Examination Survey) over 10 years (2008-2017) examined representative samples of the Korean population (n=85,006) including 2,131 infants, 4,352 preschool children, 12,919 school-age children, 44,200 adults, and 21,404 elderly adults.

RESULTS

In the 2016 to 2017 population, the estimated prevalence of asthma was 0.9% in infants, 2.3% in preschool children, 4.1% in school-age children, 2.3% in adults, and 4.1% in the elderly. The estimated prevalence of allergic rhinitis was 9.0%, 20.2%, 27.6%, 17.1%, and 6.9%, respectively. The estimated prevalence of atopic dermatitis was 5.9%, 11.3%, 14.6%, 3.9%, and 1.6%, respectively. Ten-year trends revealed a significant decrease in asthma prevalence in infants, preschool children, and the elderly. and in atopic dermatitis prevalence in infants and preschool children (P<0.05 for all trends). Furthermore, 10-year trends demonstrated a significant increase in allergic rhinitis prevalence in school-age children, adults, and the elderly, and in atopic dermatitis prevalence in school-age children and the elderly (P<0.05 for all trends).

CONCLUSION

These results improve our understanding of the age-stratified epidemiology of allergic diseases in Korea and suggest the need for the development of tailored and precise strategies to prevent allergic diseases in different age groups.

Effects of bronchoalveolar lavage on pediatric refractory mycoplasma pneumoniae pneumonia complicated with atelectasis: a prospective case-control study

BACKGROUND

There has been a paucity of data about the therapeutic efficacy of bronchoalveolar lavage (BAL) for pediatric refractory mycoplasma pneumonia pneumonia (RMPP) complicated with atelectasis. This study aimed to evaluate the clinical effectiveness and safety of BAL in pediatric RMPP inpatients complicated with atelectasis.

METHODS

Totally 225 children diagnosed as having RMPP with radiological proven irreversible atelectasis completed this study. According to whether they received BAL treatment, they were divided into BAL-intervention group (N.=125) and the control group (N.=100). Clinical, laboratory and radiological effects were compared between these two groups. Bronchoscopic imaging features were also comprehensively investigated.

RESULTS

Compared with control group, the febrile days after enrollment was significantly shorter in BAL-intervention group (3.0±1.6 d) compared with that in control group (4.1±1.7 d) (P<0.01). The duration of coughing was 3.1±1.7 d in BAL-intervention group and 4.6±1.8 days in the control group (P<0.01). The duration of abnormal lung auscultation was 3.8±1.8 d in intervention group and 5.8±1.6 d in the control group (P<0.01). The length of hospital stays was 5.8±1.6 days and 7.8±1.9 days (P<0.01), respectively. We also found that WBC count (P<0.01) and CRP value (P<0.01) recovered more quickly in BAL-intervention group compared with that in the control group. Seven days after admission, 85.6% of patients in BAL-intervention group showed atelectasis resolution versus 39.0% in control group (P<0.01), and for pleural effusion disappearance 78.4% versus 43.0% (P<0.01).

CONCLUSIONS

Our data suggested that BAL intervention combined with regular drug usage and prednisolone is a better treatment for RMPP children complicated with atelectasis than conventional drug therapy alone.

Immunochromatography for the diagnosis of Mycoplasma pneumoniae infection: A systematic review and meta-analysis

The aim of this study was to evaluate the diagnostic performance of immunochromatographic tests (ICTs) for the detection of Mycoplasma pneumoniae. Medline/Pubmed, Embase, the Cochrane Library, and ISI Web of Science were searched through June 12, 2019 for relevant studies that used ICTs for the detection of M. pneumoniae infection with polymerase chain reaction (PCR) or microbial culturing as reference standards. Pooled diagnostic accuracy with 95% confidence interval (CI) was calculated using a bivariate random effects model. We also constructed summary receiver operating characteristic curves and calculated the area under the curve (AUC). Statistical heterogeneity was evaluated by χ² test or Cochrane’s Q test. Thirteen studies including 2,235 samples were included in the meta-analysis. The pooled sensitivity and specificity for diagnosing M. pneumoniae infection were 0.70 (95% CI: 0.59–0.79) and 0.92 (95% CI: 0.87–0.95), respectively. The positive likelihood ratio (LR) was 8.94 (95% CI: 4.90–14.80), negative LR 0.33 (95% CI: 0.22–0.46), diagnostic odds ratio 29.20 (95% CI: 10.70–64.20), and AUC 0.904. In subgroup analysis, ICTs demonstrated similar pooled sensitivities and specificities in populations of children only and mixed populations (children + adults). Specimens obtained from oropharyngeal swabs exhibited a higher sensitivity and specificity than those of nasopharyngeal swab. Moreover, pooled estimates of sensitivity and accuracy for studies using PCR as a reference standard were higher than those using culture. The pooled sensitivity and specificity of Ribotest Mycoplasma^®, the commercial kit most commonly used in the included studies, were 0.66 and 0.89, respectively. Overall, ICT is a rapid user-friendly method for diagnosing M. pneumoniae infection with moderate sensitivity, high specificity, and high accuracy. This suggests that ICT may be useful in the diagnostic workup of M. pneumoniae infection; however, additional studies are needed for evaluating the potential impact of ICT in clinical practice.

[Value of lactate dehydrogenase in predicting refractory Mycoplasma pneumoniae pneumonia in children: an evaluation based on decision curve analysis and dose-response analysis]

OBJECTIVE

To study the value of lactate dehydrogenase (LDH) in predicting refractory Mycoplasma pneumoniae pneumonia (RMPP) in children.

METHODS

Propensity score matching was used to select 73 children with RMPP (refractory group) and 146 children with non-refractory Mycoplasma pneumoniae pneumonia (common group). The logistic regression analysis, restricted cubic spline model, and decision curve analysis were used to analyze the clinical value of LDH in predicting RMPP.

RESULTS

There were significant differences in the incidence of high fever, white blood cell count, platelet count, percentage of neutrophils, and serum levels of C-reactive protein, procalcitonin, hemoglobin, albumin, glutamic-pyruvic transaminase, aspartate aminotransferase and LDH (P<0.05). There were also significant differences between the two groups in the Mycoplasma pneumoniae-DNA load in nasopharyngeal aspirates and the incidences of pleural effusion, pulmonary consolidation, atelectasis, shortness of breath and skin lesions (P<0.05). The multivariate logistic regression analysis showed that high fever, hemoglobin level, LDH level, and pulmonary consolidation were independent predictive factors for RMPP (OR=10.097, 0.956, 1.006, and 3.756; P<0.05). The results of the restricted cubic spline analysis showed a non-linear dose-response relationship between the continuous changes of LDH and the development of RMPP (P<0.01). The decision curve analysis showed that LDH had an important clinical value in predicting RMPP.

CONCLUSIONS

LDH is an independent predictive factor for the development of RMPP and its intensity of association with the development of RMPP exhibits a non-linear dose-response relationship.

[Value of lactate dehydrogenase in predicting refractory Mycoplasma pneumoniae pneumonia in children: an evaluation based on decision curve analysis and dose-response analysis]

OBJECTIVE

To study the value of lactate dehydrogenase (LDH) in predicting refractory Mycoplasma pneumoniae pneumonia (RMPP) in children.

METHODS

Propensity score matching was used to select 73 children with RMPP (refractory group) and 146 children with non-refractory Mycoplasma pneumoniae pneumonia (common group). The logistic regression analysis, restricted cubic spline model, and decision curve analysis were used to analyze the clinical value of LDH in predicting RMPP.

RESULTS

There were significant differences in the incidence of high fever, white blood cell count, platelet count, percentage of neutrophils, and serum levels of C-reactive protein, procalcitonin, hemoglobin, albumin, glutamic-pyruvic transaminase, aspartate aminotransferase and LDH (P<0.05). There were also significant differences between the two groups in the Mycoplasma pneumoniae-DNA load in nasopharyngeal aspirates and the incidences of pleural effusion, pulmonary consolidation, atelectasis, shortness of breath and skin lesions (P<0.05). The multivariate logistic regression analysis showed that high fever, hemoglobin level, LDH level, and pulmonary consolidation were independent predictive factors for RMPP (OR=10.097, 0.956, 1.006, and 3.756; P<0.05). The results of the restricted cubic spline analysis showed a non-linear dose-response relationship between the continuous changes of LDH and the development of RMPP (P<0.01). The decision curve analysis showed that LDH had an important clinical value in predicting RMPP.

CONCLUSIONS

LDH is an independent predictive factor for the development of RMPP and its intensity of association with the development of RMPP exhibits a non-linear dose-response relationship.

Ameliorative effect of Albizia chinensis synthesized ZnO-NPs on Mycoplasma pneumoniae infected pneumonia mice model

BACKGROUND

Mycoplasma pneumoniae (MP) is a common cause of community-acquired pneumonia (CAP) among the children and adults that results upper and lower respiratory tract infections.

OBJECTIVE

This study was aimed to inspect the ameliorative action of A. chinensis synthesized ZnONPs against M. pneumoniae infected pneumonia mice model.

MATERIALS AND METHODS

ZnO NPs was synthesized from Albizia chinensis bark extract and characterized by UV-Vis spectroscopy, Fourier Transform Infrared (FTIR), Transmission Electron Microscopy (TEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM) analyses. The antibacterial effectual of synthesized ZnONPs were examined against clinical pathogens. The pneumonia was induced to BALB/c mice via injecting the M. pneumoniae and treated with synthesized ZnONPs, followed by the total protein content, total cell counts and inflammatory mediators level was assessed in the BALF of experimental animals. The Histopathological investigation was done in the lung tissues of test animals.

RESULTS

The outcomes of this work revealed that the formulated ZnONPs was quasi-spherical, radial and cylindrical; the size was identified as 116.5 ± 27.45 nm in diameter. The in vitro antimicrobial potential of formulated ZnO-NPs displayed noticeable inhibitory capacity against the tested fungal and bacterial strains. The administration of synthesized ZnO-NPs in MP infected mice model has significantly reduced the levels of total protein, inflammatory cells, inflammatory cytokines such as IL-1, IL-6, IL-8, tumour necrosis factor-alpha (TNF-a) and transforming growth factor (TGF). Besides, the histopathological examination of MP infected mice lung tissue showed the cellular arrangements were effectively retained after administration of synthesized ZnO-NPs.

CONCLUSION

In conclusion, synthesized ZnO-NPs alleviate pneumonia progression via reducing the level of inflammatory cytokines and inflammatory cells in MP infected mice model.

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.

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.

Plasma soluble B7-H3 levels for severity evaluation in pediatric patients with Mycoplasma pneumoniae pneumonia

Seeking for the novel biomarkers for Mycoplasma pneumoniae pneumonia (MPP) could be not only helpful for disease diagnosis but also useful for treatment efficacy monitoring. The aim of present study was to evaluate the role of plasma soluble B7-H3 (sB7-H3) in MPP diagnosis and treatment efficacy prediction, and involvement of B7-H3 in MPP disease course. A total of 108 MPP patients and 40 control subjects were recruited into this study for changes of sB7-H3 levels in MPP. In addition, a mouse model of MPP was also established for confirmation of the involvement of sB7-H3 in MPP in vivo. Significantly increased levels of sB7-H3 were found in both mild and severe MPP patients compared to control patients. Moreover, significantly increased level of sB7-H3 was also found in severe MPP patients compared to mild subjects. The ROC curve showed sB7-H3 had severity prediction capacity in mild and severe MPP. Plasma sB7-H3 correlated positively with IFN-r and GM-CSF in mild or severe MPP patients. Moreover, significantly increased level of plasma sB7-H3 level were found in acute phase MPP patients compared to control subjects, whereas significantly decreased level of plasma sB7-H3 was found in recovery phase MPP patients compared to acute phase patients. In addition, decreased levels of sB7-H3 were found in mice from Dexamethasone group compared to LAMP group. Plasma sB7-H3 level might serve as biomarker for severity MPP prediction and treatment efficacy evaluation. Furthermore, direct involvement of B7-H3 was confirmed in vivo during the MPP disease course.

Ameliorative Effects of Infantile Feire Kechuan Oral Solution on Mycoplasma Pneumoniae Pneumonia in Infant Mouse and Rat Models

Mycoplasma pneumoniae (MP) infection is a major pathogen of community-acquired pneumonia (CAP) in children worldwide. Infantile Feire Kechuan Oral Solution (IFKOS) has been used for the treatment of MP pneumonia clinically in China for many years. The present study was designed to investigate the therapeutic effect of IFKOS on MP pneumonia and explore the potential mechanism of the actions. The infant BALB/c mouse and Wistar rat models of MP infection were successfully established to confirm the therapeutic effects of IFKOS, followed by assays for related cytokines and investigations of the IgM response involved. The results showed that IFKOS exhibited an inhibitory effect on pulmonary index (PI) and effectively reduced the degree of lesions in the lungs. The lethal rate of mice was significantly decreased while survival time of mice was dramatically increased by IFKOS treatment in comparison to infection control, respectively. IFKOS treatment (40, 20, and 10ml/kg) significantly decreased the level of MP-IgM in a dose-dependent manner, whereas IFKOS showed no obvious inhibitory effect on the increase of relative expression of MP-DNA. In addition, the elevated IL-2 and TNF-α levels were significantly reduced and the decreased IL-6 level was significantly enhanced by IFKOS treatment. Our study demonstrates that IFKOS has inhibitory effect on MP infection in infant mouse and rat models of MP pneumonia and protective effect from lethal MP challenge in infant murine model. These anti-MP effects might be related to suppression of the IgM response and a reversal the imbalance of Th1/Th2 cytokines induced by MP infection.

High expression of HMGB1 in children with refractory Mycoplasma pneumoniae pneumonia

Background

Increasing numbers of refractory or severe, even fatal, cases of Mycoplasma pneumoniae infections have been reported in recent years. Excessive inflammatory responses play a vital role in the pathogenesis of refractory M. pneumoniae pneumonia (RMPP). HMGB1 is an actively secreted cytokine produced by macrophages and other inflammatory cells that participates in various infectious diseases. The present study aimed to explore the role and clinical significance of HMGB1 in children with RMPP and the potential mechanism of HMGB1 expression.

Methods

Four hundred and fifty-two children diagnosed with M. pneumoniae pneumonia, including 108 children with RMPP, were enrolled from January 2013 to December 2015 at the Children’s Hospital of Soochow University. HMGB1, TNF-α, and IL-6 in peripheral blood from RMPP and non-RMPP (NRMPP) cases were detected by real-time PCR and ELISA. Lipid-associated membrane proteins (LAMPs) were extracted from live M. pneumoniae and prepared at different concentrations for stimulation of THP-1 cells. After coculture with LAMPs, HMGB1, TNF-α, IL-6, RAGE, TLR2, and TLR4 in THP-1 cells were detected by real-time PCR.

Results

Occurrences of cough, fever, and abnormal lung signs were more frequent in RMPP cases compared with NRMPP cases (all p < 0.05). Children with RMPP had longer hospital stays than children with NRMPP (p < 0.05). Different distributions of lymphocytes were noted between RMPP and NRMPP cases. HMGB1, TNF-α, and IL-6 levels were significantly higher in RMPP cases compared with NRMPP cases (all p < 0.05). HMGB1 had good diagnostic ability to differentiate RMPP with AUC of 0.876, sensitivity of 0.833, and specificity of 0.824 compared with TNF-α and IL-6. HMGB1 expression in THP-1 cells was increased by stimulation with 10 μg/ml LAMPs. TLR2 expression was increased after stimulation with 6 μg/ml LAMPs. HMGB1 level was positively associated with TNF-α, IL-6, and TLR2 levels.

Conclusions

HMGB1 is a good diagnostic biomarker for differentiating RMPP and NRMPP. LAMPs from M. pneumoniae may induce HMGB1 expression in immune cells through the TLR2 pathway. Further in vitro and in vivo studies are needed for the development of a new treatment strategy to inhibit the HMGB1 pathway, thereby preventing the inflammation in RMPP.

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.

Challenges in identifying antibiotic resistance targets for point-of-care diagnostics in general practice

General practitioners stand at the front line of healthcare provision and have a pivotal role in the fight against increasing antibiotic resistance. In this respect, targeted antibiotic prescribing by general practitioners would help reduce the unnecessary use of antibiotics, leading to reduced treatment failures, fewer side-effects for patients and a reduction in the (global) spread of antibiotic resistances. Current 'gold standard' antibiotic resistance detection strategies tend to be slow, taking up to 48 h to obtain a result, although the implementation of point-of-care testing by general practitioners could help achieve the goal of targeted antibiotic prescribing practices. However, deciding on which antibiotic resistances to include in a point-of-care diagnostic is not a trivial task, as outlined in this publication.