Clinical characteristics of community-acquired pneumonia in children caused by mycoplasma pneumoniae with or without myocardial damage:A single-center retrospective study

BACKGROUND Mycoplasma pneumoniae(MP)is a prevalent pathogen that causes respiratory infections in children and adolescents.AIM To assess the differences in the clinical features of MP-associated communityacquired pneumonia(CAP)in children who presented with mild or severe mycoplasma pneumoniae pneumonia(MPP);to identify the incidence of myocardial damage between the two groups.METHODS This work is a retrospective study.We identified children between 2 mo and 16 years of age with clinical and radiological findings consistent with CAP.We admitted patients to the inpatient department of the Second Hospital of Jilin University,Changchun,China,from January 2019 to December 2019.RESULTS A total of 409 hospitalized patients were diagnosed with MPP.Among them were 214(52.3%)males and 195(47.7%)females.The duration of fever and cough was the longest in severe MPP cases.Similarly,plasma levels of highly sensitive Creactive protein(t=-2.834,P<0.05),alanine transaminase(t=-2.511,P<0.05),aspartate aminotransferase(t=-2.939,P<0.05),and lactate dehydrogenase(LDH)(t=-2.939,P<0.05)were all elevated in severe MPP cases compared with mild MPP cases,and these elevations were statistically significant(P<0.05).Conversely,the neutrophil percentage was significantly lower in severe MPP cases than in mild MPP cases.The incidence of myocardial damage was significantly higher in severe MPP cases than in mild MPP cases(χ^(2)=157.078,P<0.05).CONCLUSION Mycoplasma pneumoniae is the main cause of CAP.The incidence of myocardial damage was higher and statistically significant in severe MPP cases than in mild MPP cases.

Chinese herbal medicine combined with Western medicine for Mycoplasma pneumoniae pneumonia in children:An overview of systematic reviews

Objective:To summarize the characteristics and evaluate the quality of the methodology and evidence within systematic reviews(SRs)of Chinese herbal medicine(CHM)for Mycoplasma pneumoniae pneumonia(MPP)inchildren.Methods:SRs of randomized controlled trials were searched using PubMed,the Cochrane Library,Embase,the Chinese National Knowledge Infrastructure Databases(CNKI),the Chinese Scientific Journals Database(VIP),Wanfang,and the SinoMed Database.SRs on the use of CHM alone or in combination with Western medications for MPP in children were included.The study compared the effects of Western medicine alone with those of CHM.The evidence quality using the A Measurement Tool to Assess Systematic Reviews(AMSTAR)2,the Preferred Reporting Items for Systematic Reviews and Meta-Analyses(PRISMA)2020,and the Grading of Recommendations,Assessment,Development,and Evaluation(GRADE)criteria.The primary indicators were the total effective rate,fever subsidence time,and cough disappearance time.The secondary outcomes were pulmonary rale disappearance time,average hospitalization time,lung X-ray infiltrate disappearance time,immunological indices,and inflammatory cytokine levels.Results:Twelve relevant SRs were included;75%(9/12)were assessed as very low quality,and 25%(3/12)Were rated as low quality using the AMSTAR 2 criteria.According to the PRISMA 2020 checklist,the average SR score was 20.3 out of a 27 point maximum.In all SRs,CHM demonstrated improvement in symptoms and signs among children with MPP.The evidence quality using the GRADE criteria ranged from"very low"(>50%)to"moderate"(<5%).The most common downgrading factor was imprecision,followed by publication bias and inconsistency.Conclusion:This overview highlights the limited quality of the methodology and evidence of the included SRs.Although the included studies showed the beneficial effects of CHM on MPP in children,it was difficult to draw firm conclusions owing to methodological flaws.

The value of IgM and IgG contents for the diagnosis and judgment of mycoplasma pneumonia in children

Objective: To explore the value of IgM and IgG contents for the diagnosis and judgment of mycoplasma pneumonia in children. Methods: 560 children with mycoplasma pneumonia who received inpatient treatment in our hospital between October 2016 and October 2017 were selected as mycoplasma pneumonia group, and 200 healthy children who received vaccination in our hospital during the same period were selected as normal control group. The differences in peripheral blood IgM and IgG contents as well as serum inflammatory factor and pulmonary surfactant protein contents were compared between the two groups, and Pearson test was used to evaluate the inner link of peripheral blood IgM and IgG contents with inflammatory factors and pulmonary surfactant proteins in children with mycoplasma pneumonia. Results: Peripheral blood IgM and IgG contents of mycoplasma pneumonia group were higher than those of normal control group;serum inflammatory factors MCP-4, IL-5, IL-13, IL-17, IL-18 and IL-23 contents were higher than those of normal control group;serum pulmonary surfactant proteins SP-A, SP-B, SP-C and SP-D contents were higher than those of normal control group. Correlation analysis showed that peripheral blood IgM and IgG contents in children with mycoplasma pneumonia were positively correlated with the contents of inflammatory factors and pulmonary surfactant proteins. Conclusion: Peripheral blood IgM and IgG contents are abnormally high in children with mycoplasma pneumonia, and they are closely related to the inflammatory response and lung injury degree.

Interpretation of Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia(Trial Version 7)

On March 3,2020,the National Health Commission and the National Administration of Traditional Chinese Medicine of China jointly promulgated the Notice on Printing and Distributing the Diagnosis and Treatment Protocol for Novel Coronavirus Pneumonia(Trial Version 7).The content has been revised and supplemented on the basis of the Version 6,including etiological characteristics and pathological changes in lung,heart,kidney,spleen,liver,gallbladder,esophagus,stomach and intestinal mucosal epithelium.In particular,the diagnosis and treatment methods of traditional Chinese medicine are supplemented.It provides an evidence-based diagnosis and treatment protocol for the treatment and recovery of suspected and confirmed cases of novel coronavirus pneumonia with traditional Chinese medicine and Western medicine.

The Effect of Azithromycin in Treating Mycoplasma Pneumonia in Children

Objective:To discuss and analyze the effect of azithromycin in the treatment of mycoplasma pneumonia in children.Methods:A total of 120 children with mycoplasma pneumonia who were admitted to the Department of Pediatrics of our hospital from January 2022 to December 2022 were selected as the research subjects.They were divided into an azithromycin group and a reference group according to the random number drawing method,with 60 cases in each group.The azithromycin group was treated with azithromycin,and the reference group was treated with conventional treatment.The efficacy of treatment,laboratory indicators,platelet count and D-dimer,and adverse reactions of both groups were compared.Results:The efficacy of the azithromycin group was significantly higher than that of the reference group(P<0.05).Before treatment,there were no significant differences in the laboratory indicators like ferritin,procalcitonin(PCT),and erythrocyte sedimentation rate(ESR)between the two groups(P>0.05);after treatment,the laboratory indicators of the azithromycin group were significantly better than those of the reference group(P<0.05).Before treatment,there was no statistically significant difference in platelet count and D-dimer between the groups(P>0.05);after medication,the platelet count,and D-dimer in the azithromycin group were significantly better than those in the reference group(P<0.05).The total incidence of adverse reactions in the azithromycin group was significantly lower than that in the reference group(P<0.05).Conclusion:Azithromycin is more effective in treating mycoplasma pneumonia in children,and has certain clinical value.

A New Childhood Pneumonia Diagnosis Method Based on Fine-Grained Convolutional Neural Network

Pneumonia is part of the main diseases causing the death of children.It is generally diagnosed through chest Xray images.With the development of Deep Learning(DL),the diagnosis of pneumonia based on DL has received extensive attention.However,due to the small difference between pneumonia and normal images,the performance of DL methods could be improved.This research proposes a new fine-grained Convolutional Neural Network(CNN)for children’s pneumonia diagnosis(FG-CPD).Firstly,the fine-grainedCNNclassificationwhich can handle the slight difference in images is investigated.To obtain the raw images from the real-world chest X-ray data,the YOLOv4 algorithm is trained to detect and position the chest part in the raw images.Secondly,a novel attention network is proposed,named SGNet,which integrates the spatial information and channel information of the images to locate the discriminative parts in the chest image for expanding the difference between pneumonia and normal images.Thirdly,the automatic data augmentation method is adopted to increase the diversity of the images and avoid the overfitting of FG-CPD.The FG-CPD has been tested on the public Chest X-ray 2017 dataset,and the results show that it has achieved great effect.Then,the FG-CPD is tested on the real chest X-ray images from children aged 3–12 years ago from Tongji Hospital.The results show that FG-CPD has achieved up to 96.91%accuracy,which can validate the potential of the FG-CPD.

Early Imaging Features and Differential Diagnosis of Novel Coronavirus Pneumonia

Objective:To discuss the early imaging features of novel coronary pneumonia(NCP)and its differential diagnosis with common pneumonia for the clinical Provide relatively correct imaging diagnosis.Methods:A review of 10 cases of novel coronavirus pneumonia diagnosed in our hospital and surrounding counties was collected,and our hospital's 2019-2020 Common pneumonia such as influenza A and B virus pneumonia,lobar pneumonia and adenovirus confirmed by laboratory tests and abnormal chest radiographs Ten patients each with pneumonia,a total of 40 patients,were collected and their imaging features were analyzed.Results:In 10 patients with neo-coronary pneumonia,there were 30 lesions on chest CT,with typical characteristic lesions containing bronchograms within their Angiographic thickening;located in the subpleura,with grinding glass-like or combined solid changes,referred to as"extratubular halo",with multifocal and multifocal distribution.Morphology or unilobular large lamellar foci without lymph node enlargement and pleural effusion;10 cases of influenza A and B virus pneumonia in chest CT performance In nine patients,the lesions were distributed in the subpleural or along the perimeter of the bronchial vessels in the form of an analogous circular ground-glass shadow,some of which was a small piece of solid shadow,1 The case involved a single lobe of the lung and showed a large mixed ground glass image,and the CT in 10 cases of lobar pneumonia showed that they all had a single large solid lobe The variegated shadow or patchy cloud with blurred margins was triangularly altered with the tip pointing to the lung portal,and there were five cases of air-containing bronchograms.Adenoviral pneumonia is more common in infants and young children,and CT showed single or multiple grinded glass images in both lungs with patchy solid variegated shadows and lobar distribution.Conclusion:NCP and common pneumonia have certain imaging features that,in combination with laboratory tests and epidemiologic history,allow a preliminary diagnosis to be made.It has certain directions and help for clinical diagnosis.

Preventive Effects of Five Drugs on Mycoplasma Pneumonia of Swine (MPS)

The paper was to explore the preventive effects of five drugs on mycoplasma pneumonia of swine （MPS） and to provide reference for clinical medication of pig farms in Hainan Province. A total of 444 health piglets were randomly divided into 6 groups, including five medication groups （72 piglets in group A, 74 pig- lets in group B, 72 piglets in group C, 76 piglets in group D, 76 piglets in group E） and one control group （74 piglets）. The piglets in experimental groups were treated drugs once a day for successive 5 days at 30, 60, 90, 120 and 150 of age. The piglets in control group were free of medication. At 70 and 140 days of age, 15 piglets of each group were randomly selected to collect their blood sermn. The Mycoplasma hyopneumoniae （M-Hyo） antibodies in serum were measured by en- zyme-linked immunosorbent assay （ELISA）. During the experiment, the incidence rates of respiratory disease, lung lesion, feed conversion rate, average daily gain （ADG）, and mortality rate of pigs were also observed and recorded. The results showed that the five drugs had significant difference in preventative effects. Group C （Zhiyuanjing group） received the best preventive effect and the highest economic benefits. Compared with control group, the ADG and feed conversion rate in group C were increased by 7.53% and 9.09%, respectively; the incidence rate of respiratory disease was reduced by 13.44% and lung lesion was alleviated by 81.43% ; and the earnings of each pig could rise by 132.70 yuan. The preventative effect and economic benefit of the drugs was sequenced by Chansu Kechuanling and Bingchan Kechuanwang. Wante Feilin and amoxicillin had weaker preventive effects against MPS but greatly influenced growth performance of pigs, so they should be used alternatively with other drugs.

Standardization of a Real-time PCR System for Quantitative Detection of Mycoplasma hyopneumoniae

This study was conducted to develop a method for accurate quantification of Mycoplasma hyopneumoniae during vaccine production or experimental research. Primer and probe concentration that gave the highest ΔRn and the lowest Ct were selected to establish the real-time PCR system for the detection of M. hyopneumoniae. Template DNA of M. hyopneumoniae was extracted by boiling under different conditions and detected by real-time PCR to determine the optimal conditions for DNA extraction. Thereafter, intra-and inter-batch reproducibility tests were carried out using a standard plasmid to evaluate the stability of the PCR system. Subsequently, the effect of medium composition on the quantitative detection was evaluated. Finally, the correlation between real-time PCR and CCU method was explored. The optimal primer and probe concentration for real-time PCR were 0.4 and 0.2 μmol/L, respectively. The intra-and inter-batch coefficients of variation(CV) in Ct value of 10~4-10~9 copies/μl standard plasmid were <5%, indicating good reproducibility of the real-time PCR system. Following incubation in a boiling water bath for 10 min, M. hyopneumoniae samples can be used directly as a template in subsequent real-time PCR assays,and good intra-batch and inter-batch reproducibility was observed. The working concentration of KM2 medium should be less than the 1/10 of the concentration of the stock solution to minimize its influence on the quantitative detection. Spearman's correlation analysis revealed that the log of CCU and the log of DNA copy number had a significant positive relationship(r=0.797,P=0.000). Thus, the two methods can be used in combination in the quantitative detection of M. hyopneumoniae. In summary, a rapid, stable and accurate quantitative PCR system for detecting M. hyopneumoniae culture was established in this study, which provides a technical means for accurate quantification of M. hyopneumoniae in vaccine production and laboratory tests.

Correlation of serum complement and immunoglobulin contents with inflammatory stress response in children with Mycoplasma pneumoniae pneumonia

Objective:To study the correlation of serum complements C3 and C4 as well as immunoglobulins IgM, IgA and IgG contents with inflammatory stress response in children with mycoplasma pneumoniae pneumonia.Methods: The children who were diagnosed with Mycoplasma pneumoniae pneumonia in Xiangyang No. 1 People's Hospital, Hubei University of Medicine between February 2015 and January 2018 were selected as the MPP group, and healthy children who received physical examination during the same period were selected as the control group. The contents of complements, immunoglobulins and inflammatory stress mediators in serum as well as the expression of inflammatory stress molecules in peripheral blood were measured.Results: Serum C3, C4, IgM, sICAM-1, CD40L, HMGB1, Cor and MDA levels as well as peripheral blood TLR2, TLR4, CD11b, CD18, MPO and NOX2 expression intensity of MPP group were significantly higher than those of control group, IgA level was significantly lower than that of control group, and IgG level was not different from that of control group;serum C3, C4 and IgM levels of MPP group were positively correlated with serum sICAM-1, CD40L, HMGB1, Cor and MDA levels as well as peripheral blood TLR2, TLR4, CD11b, CD18, MPO and NOX2 expression intensity, and serum IgA level was negatively correlated with serum sICAM-1, CD40L, HMGB1, Cor and MDA levels as well as peripheral blood TLR2, TLR4, CD11b, CD18, MPO and NOX2 expression intensity. Conclusion: The changes of serum complements and immunoglobulins in children with Mycoplasma pneumoniae pneumonia are related to the excessive activation of inflammatory stress response in the course of disease.

Status of <i>Mycoplasma pneumoniae</i>Pneumonia in Chinese Children: A Systematic Review

Mycoplasma pneumoniae pneumonia (MPP) becomes one of the most important health problems in China recently. Date for MPP inChinais scarce. Although macrolides and/or cortical steroids had been reported to be effective treatment for MPP, the long-term outcome remained uncertain. A study on status of MPP in China was conducted via a systematic review of published studies which have the Chinese data and collected from published PubMed and core journals of China Knowledge Resource Integrated Database (CNKI). The analysis was based on epidemiology, clinical characteristics, treatment, drug resistance and prognosis. Twenty five articles concerned about MPP in Chinese children and adolescent were enrolled, including 11 studies on epidemiology/etiology, 11 studies on clinical characteristics, 7 studies on drug resistance, 5 studies on treatment from China's Mainland respectively. The overall incidence of MPP ranged from 7.1% to 54.4%. Fever and cough were most frequently identified in manifestations. Drug resistance to macrolides ranged from 18.9% to 90%. The outcome of treatment in patients who received combined treatment of macrolides, cephalosporin antibiotics and/or cortical steroid seems to be better than those who received macrolides only. Macrolide combined with cephalosporin or cortical steroid both may decrease the severity of MPP in the past decade. There was not enough evidence to suggest that cortical steroid can decrease the mortality of MPP in children. And a multi-center, randomized double blind research on the effect of cortical steroid was encouraged.

Involvement of TLR2 and TLR4,Chlamydophila pneumoniae and Mycoplasma pneumoniae in adventitial inflammation of aortic atherosclerotic aneurysm

Aortic atherosclerotic aneurysm (AAA) is associated with adventitial inflammation where infection is suggested to have a role. Co-infection with Chlamydophila pneumoniae (Cp) and Mycoplasma pneumoniae (Mp) was linked with coronary plaque rupture, in association with vessel dilatation and adventitial inflammation. Pathogens are recognized by Toll-like receptors (TLRs) development of the inflammatory process. Objective: Here, we studied whether co-infection by Cp and Mp was involved in the increased inflammation present in AAA and if it could be associated with deficient expression of TLRs. We compared human samples of AAA with non-dilated human aortic atherosclerotic lesions, regarding the amount of Cp and Mp antigens, and expression of TLR2 and TLR4. Methods: Two groups of aorta fragments were analyzed: G1 (n = 13) moderate atherosclerosis and G2 (n = 14) AAA samples, through immunohisto-chemistry and in situ hybridization methods. Results: Mp and Cp antigens in intima/medial layer were greater in G2 than G1, with no difference in adventitia. TLR2 and TLR4 were higher in G2 than G1 adventitia fat. There was a correlation between Mp versus TLR2 and of TLR4 in intima/medial layer and in adventitia of G1, but there was a lack of correlation in G2. In Cp adventitia, the correlation in G1 was high with TLR2 but not with TLR4, and in G2 the correlation was positive for both TLRs. Conclusion: This study favors the concept that symbiotic co-infection by Cp and Mp participates in the pathogenesis of AAA. It also emphasizes that adventitial fat is the initial site for colonization of these bacteria that probably reach the tissue through vasa vasorum. An exacerbated immune reaction is not efficient to control the infection that reaches and proliferates in high levels at the medial and intimal layer, contributing to the development of vessel dilatation.

Evaluation of a New Real-time PCR Assay for Detection of Mycoplasma Pneumoniae in Clinical Specimens

Objective To establish and evaluate a real-time PCR assay to detect Mycoplasma pneumoniae （M.pneumoniae） in clinical specimens. Methods By analysing the whole pl gene sequence of 60 M.pneurnoniae clinical isolates in Beijing of China, an optimized real-time PCR assay （MpP1） using pl gene conserved region was designed. The specificity and sensitivity of this assay were evaluated and compared with other two reported assays （RepMpl and Mp181） using 40 positive and 100 negative clinical specimens. Results The detection limit of the new assay was 8.1 fg （about 1-3CFU） M.pneumoniae DNA. The sensitivity of MpP1, RepMpl, and Mp181 assays appeared to be 100%, 100%, and 85%, respectively. Conclusion MpP1 assay is suitable for the detection of M.pneumoniae in Chinese clinical specimens.

Mycoplasma pneumoniae Macrolide Resistance and MLVA Typing in Children in Beijing,China,in 2016:Is It Relevant?

Objective The aim of this study is to investigate the macrolide resistance rate and molecular type with multiple-locus variable-number tandem-repeat analysis(MLVA)of Mycoplasma pneumoniae of Beijing in 2016 in pediatric patients.Methods Real-time quantitative polymerase chain reaction(PCR)was used to identify M.pneumoniae,and MLVA was performed.The domain V of the 23 S rRNA was sequenced to detect macrolide-resistant point mutations.We also investigated the activities of antibiotics against M.pneumoniae isolates in vitro.Results The PCR detection rate of M.pneumoniae in children in Beijing was 40%,and the macrolide resistance rate was 66%.The A2063 G mutation in the 23 S rRNA V region is the dominant mutation(137/146,93.84%),whereas the A2064 G mutation is rare(9/146,6.16%).Seventy-three samples were typed successfully by MLVA typing,including 86.3%(63/73)were MLVA type 4-5-7-2,and 13.7%(10/73)were MLVA type 3-5-6-2.No other types were found.No strains were resistant to levofloxacin or tetracycline.Conclusion In 2016,a specific decrease in the macrolide resistance rate occurred in Beijing.The detection rate and macrolide resistance rate of outpatients are lower than those of inpatients.The A2063 G mutants M.pneumoniae have high levels of resistance to erythromycin and azithromycin.The primary MLVA type is 4-5-7-2,followed by 3-5-6-2.No other MLVA types were detected.No strains resistant to tetracycline or levofloxacin were found in vitro.

Correlation Between the Clinical Severity, Bacterial Load, and Inflammatory Reaction in Children with Mycoplasma Pneumoniae Pneumonia

Given the lack of defining features in the clinical manifestations and radiographic findings for children with mycoplasma pneumoniae pneumonia(MPP),quantitative polymerase chain reaction(qPCR)has become a useful diagnostic method.This study was performed to explore the relationship between the qPCR findings,clinical symptoms,and inflammatory markers in children with MPP.Four hundred children with MPP have been enrolled in this retrospective analysis.All clinical and analytical information,including mycoplasma pneumoniae(MP)PCR results,has been collected.Based on the PCR results,the patients were divided into groups with load values(copy number)<105(54 cases),2105 and<106(71 cases),2106 and<107(112 cases),>107 and<108(114 cases),and>108(49 cases).The clinical features(including symptoms and signs)and inflammatory indicators were compared among the groups.The incidence of high fever(above 39℃),thermal peak during the entire hospitalization period,fever duration,days of hospitalization,and plasma lactate dehydrogenase(LDH)levels were statistically correlated with the MP PCR load value in children with MPP.The analysis of relevance degree showed the correlative order as a thermal peak of hospitalization>duration of fever>period of hospitalization>LDH value>C-reactive protein value.The host immune response was significantly greater in the complication group than in the non-complication group.

Establishment of a Predictive Diagnostic Model for Acute Mycoplasma Pneumoniae Infection in Elderly Patients with Community-acquired Pneumonia

We established a diagnostic model to predict acute Mycoplasma pneumoniae （M. pneumonia） infection in elderly Community-acquired pneumonia （CAP） patients. We divided 456 patients into acute and non-acute M. pneumoniae infection groups. Binary logistic regression and receiver operating characteristic （ROC） curves were used to establish a predictive model. The following independent factors were identified： age 〉 70 years; serum cTNT level 〉 0.0S ng/mL; lobar consolidation; mediastinal lymphadenopathy; and antibody titer in the acute phase 〉 1：40. The area under the ROC curve of the model was 0.923 and a score of 2 7 score predicted acute M. pneumoniae infection in elderly patients with CAP. The predictive model developed in this study has high diagnostic accuracy for the identification of elderly acute M. pneumoniae infection.

The Expression of PDGF-B Chain mRNA in Lung Tissue from Rats Repeatedly Infected with Mycoplasma Pneumoniae

In order to investigate the role played by platelet derived growth factor-BB (PDGF-BB) in the pathogenesis of pulmonary interstitial fibrosis in rats repeatedly infected with mycoplasma pneumoniae (MP), a rat MP infection model was developed by infecting rats with MP for 9 times during a period of 24 weeks with a technique of ultrasonic nebulizing inhalation. Then in situ hybridization was performed with PDGF-B chain cDNA probe and the results were quantitatively analyzed to measure the changes in PDGF-B chain mRNA expression in the lung tissue. The results showed that: (1) MP polymerase chain reaction (PCR) tests showed positive results in the bronchoalveolar lavage fluid (BALF ) from all of the MP-infected rats (n = 4) while they were all negative in BALF from the control animals (n = 4, P<0. 05) and in BALF from those rats both infected with MP and, at the same time, treated with erythromycin (n = 4, P<0. 05). Bacterial cultures of the bronchial and lung tissue were negative in all three groups. The observation under a transmission electron microscope indicated that the interalveo-lar septa were widened with increased amount of collagen in the MP-infected rats while there were no obvious abnormalities in the other two groups. (2) Strong positive expression of PDGF-B chain mRNA was found in the plasma of mono-cytes and macrophages located in the locally widened interalveolar septa and alveolar spaces in the lung tissue from the MP-infected animals with the integral optical densities being 37. 42 ±9. 05 (n = 4) which was significantly higher than the values of control group (0. 42 + 0. 08, n = 4, P<0. 01) and of the group with MP-infec-tion plus erythromycin treatment (1. 62 ± 0. 40, n = 4, P<0. 01). These results suggest that PDGF-BB may be involved in the process of the development of pulmonary interstitial fibrosis caused by the repeated MP-infection. It may be an important growth factor for mediating the roles of monocytes and macrophages to promote the aggregation and proliferation of fibroblasts which can then secrete collagen in large quantity in the pulmonary interstitium.

Using 16S rDNA Sequencing Technology to Preliminarily Analyze Intestinal Flora in Children with Mycoplasma pneumoniae Pneumonia

Objective We investigated changes in the intestinal flora of children with Mycoplasma pneumoniae pneumonia(MPP).Methods Between September 2019 and November 2019,stool samples from 14 children with MPP from The Fourth Hospital of Baotou city,Inner Mongolia Autonomous Region,were collected and divided into general treatment(AF)and probiotic(AFY)groups,according to the treatment of“combined Bifidobacterium,Lactobacillus,Enterococcus,and Bacillus cereus tablets live”.Highthroughput 16S rDNA sequencing was used to identify intestinal flora.Results Intestinal flora abundance and diversity in children with MPP were decreased.Both Shannon and Simpson indices were lower in the AF group when compared with healthy controls(P<.05).When compared with healthy controls,the proportion of Enterorhabdus was lower in the AF group,while the proportion of Lachnoclostridium was higher(P<0.05).The proportion of Bifidobacteria and Akkermansia was lower in the AFY group but Enterococcus,Lachnoclostridium,Roseburia,and Erysipelatoclostridium proportions were higher.The proportion of Escherichia coli-Shigella in the AFY group after treatment was decreased(P<0.05).Conclusions The intestinal flora of children with MPP is disturbed,manifested as decreased abundance and diversity,and decreased Bifidobacteria.Our probiotic mixture partly improved intestinal flora disorders.

The Effect of Vitamin A on Secretion of IFN-γ and IL-4 in A549 Cells Induced by Mycoplasma Pneumoniae

In order to investigate the effect of vitamin A （VA） on the secretion of IFN-γ and IL-4 in Mycoplasma Pneumoniae （MP）-induced A549 cells, A549 cells were co-cultured with MP for different time lengths and then the levels of IFN-γ and IL-4 in the cell culture supernatants were detected before and after treatment with different concentrations of VA by using the enzyme-linked immu-nosorbent assay （ ELISA）. The results showed that the level of IFN-γ and IL-4 in the supernatants of MP-induced A549 cells was much higher than that in non-induced cells （P〈0.01）. After application of VA, IL-4 level was not increased until the concentration of VA was up to 0.5×10-5 mol/L （P〈0.01）. However, with concentration of VA increased up to 1×10-4 mol/L, IL-4 was significantly suppressed （P〈0.01）. It was concluded that MP could induce the secretion of IFN-γ and IL-4 in A549 cells. VA could inhibit the secretion of IFN-γ and increase the IL-4 level in MP-induced A549 cells. However, high concentration of VA had an inhibitory effect on the secretion of IL-4 as well as on the IFN-γ. These data provided a theoretical basis for the application of VA in MP pneumonia in the clinical practice.

Whole Genome Analysis Reveals New Insights into Macrolide Resistance in Mycoplasma pneumoniae

Objective Mutations in 23 S rRNA gene are known to be associated with macrolide resistance in Mycoplasma pneumoniae（M. pneumoniae）. However, these mutations alone do not fully explain the high resistance rates in Asia. The aim of this study was to investigate other possible mutations involved in macrolide resistance in M. pneumoniae. Methods The whole genomes of 10 clinical isolates of M. pneumoniae with macrolide resistance were sequenced by Illumina Hi Seq2000 platform. The role of the macrolide-specific efflux transporter was assessed by efflux-pump inhibition assays with reserpine and carbonyl cyanide m-chlorophenyl-hydrazone（CCCP）. Results A total of 56 single nucleotide polymorphisms（SNPs） were identified in 10 clinical isolates in comparison to the reference strains M129 and FH. Strikingly, 4 of 30 SNPs causing non-synonymous mutations were clustered in macrolide-specific efflux system gene mac B encoding macrolide-specific efflux pump protein of the ATP-binding cassette transporter family. In assays of the minimal inhibitory concentrations（MIC） of macrolide antibiotics in the presence of the efflux pump inhibitors caused a significant decrease of MICs, even under detectable levels in some strains. Conclusion Our study suggests that macrolide efflux pump may contribute to macrolide resistance in M. pneumoniae in addition to the common point mutations in 23 S r RNA gene.