Clinical manifestations in infants and children with Mycoplasma pneumoniae infection

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Clinical features of Mycoplasma pneumoniae pneumonia in children without fever

BACKGROUND

Mycoplasma pneumoniae (MP) is one of the most common causes of community-acquired pneumonia in children. Most children have fever. In 2021, we found that the proportion of children without fever increased. The aim of this study is to summarize the differences in the clinical characteristics of children with MP pneumonia who are febrile or not, and to raise awareness of children who are not febrile.

METHOD

Demographic information of the children was collected on admission. Clinical manifestations during the course of the disease and the first laboratory, imaging, and pulmonary function tests before discharge were recorded and compared.

RESULTS

From August to December, a total of 542 people were included in the study. We found that older children were more likely to have fever. Inflammatory indicators including procalcitonin (P = 0.030), C-reaction protein (P < 0.001), erythrocyte sedimentation rate (P < 0.001), ferritin (P = 0.040) and the rate of atelectasis (P = 0.049) of febrile children were higher in febrile children. However, the elevated lactate dehydrogenase and pulmonary function impairment (P all > 0.05), especially the small airway function impairment, are no lower in afebrile children than in febrile children.

CONCLUSION

The fever rate is lower in younger children, but wheezing is more common. In afebrile children, the impairment of organ and lung function was no less than in febrile children. Therefore, attention should also be paid to children who are not febrile.

Increased incidence of Mycoplasma pneumoniae infections and hospital admissions in the Netherlands, November to December 2023

Mycoplasma pneumoniae is an important cause of pneumonia and extra-pulmonary manifestations. We observed a rise in admissions due to M. pneumoniae infections starting October 2023 in a regional hospital in the Netherlands and an increased incidence in national surveillance data. The incidence in the Netherlands has not been that high since 2011. The patients had a lower median age compared with 2019 and 2020 (28 vs 40 years). M. pneumoniae should be considered in patients with respiratory symptoms, especially children.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Optimization strategy for the early timing of bronchoalveolar lavage treatment for children with severe mycoplasma pneumoniae pneumonia

BACKGROUND

Early evaluation of severe mycoplasma pneumoniae pneumonia (SMPP) and the prompt utilization of fiberoptic bronchoscopic manipulation can effectively alleviate complications and restrict the progression of sequelae. This study aim to establish a nomogram forecasting model for SMPP in children and explore an optimal early therapeutic bronchoalveolar lavage (TBAL) treatment strategy.

METHODS

This retrospective study included children with mycoplasma pneumoniae pneumonia (MPP) from January 2019 to December 2021. Multivariate logistic regression analysis was used to screen independent risk factors for SMPP and establish a nomogram model. The bootstrap method was employed and a receiver operator characteristic (ROC) curve was drawn to evaluate the accuracy and robustness of the model. Kaplan-Meier analysis was used to assess the effect of lavage and hospitalization times.

RESULTS

A total of 244 cases were enrolled in the study, among whom 68 with SMPP and 176 with non-SMPP (NSMPP). A prediction model with five independent risk factors: left upper lobe computed tomography (CT) score, sequential organ failure assessment (SOFA) score, acute physiology and chronic health assessment (APACHE) II score, bronchitis score (BS), and c-reactive protein (CRP) was established based on the multivariate logistic regression analysis. The ROC curve of the prediction model showed the area under ROC curve (AUC) was 0.985 (95% confidence interval (CI) 0.972-0.997). The Hosmer-Lemeshow goodness-of-fit test results showed that the nomogram model predicted the risk of SMPP well (χ2 = 2.127, P = 0.977). The log-rank result suggested that an early BAL treatment could shorten MPP hospitalization time (P = 0.0057).

CONCLUSION

This nomogram model, based on the left upper lobe CT score, SOFA score, APACHE II score, BS, and CRP level, represents a valuable tool to predict the risk of SMPP in children and optimize the timing of TBAL.

Nasopharyngeal detection of atypical bacteria by multiplex polymerase chain reaction panel in acutely ill children was associated with an increased risk of pneumonia

AIM

We aimed to assess whether detection of respiratory bacteria by multiplex polymerase chain reaction (PCR) testing associates with clinical outcomes in acutely ill children.

METHODS

This cross-sectional study enrolled children under the age of 18 with a suspected respiratory infection treated in a paediatric emergency department of Oulu University Hospital, Finland from January 2015 through December 2015. Nasopharyngeal samples were routinely analysed for 16 respiratory viruses and later, after storage, analysed with a multiplex PCR panel for seven respiratory bacteria.

RESULTS

At least one bacterial pathogen was detected in 600 out of the 1195 children (50%). The mean age was 3.3 (SD 3.7) years and 54% were boys. Atypical bacteria were associated with a risk of pneumonia (adjusted odds ratio [aOR] 14.1, 95% CI 3.98-50.1). Co-detection of rhinovirus with Streptococcus pneumoniae was not associated with risk of pneumonia (aOR 2.39, 95% CI 0.78-7.30). Detection of Streptococcus pneumoniae, Haemophilus influenzae or both was not associated with the risk of hospital admission or prescription of antibiotics.

CONCLUSION

Nasopharyngeal detection of atypical bacteria in acutely ill children was associated with a markedly increased risk of pneumonia. The clinical utility of wide testing for other respiratory bacteria needs further evaluation.

Modern approaches at the management of children with community-acquired pneumonia

Experts of The Union of Pediatricians of Russia have developed current clinical guidelines for management of children with community-acquired pneumonia, which were approved by the Scientific and Practice Council of Ministry of Public Health of the Russian Federation in January 2022. Particular attention is paid to the etiological structure, modern classification, diagnostic tests and flagship approaches to antibacterial therapy of community-acquired pneumonia in children based on the principles of evidentiary medicine. 

Infectious and Inflammatory Pathways to Cough

Coughing is a dynamic physiological process resulting from input of vagal sensory neurons innervating the airways and perceived airway irritation. Although cough serves to protect and clear the airways, it can also be exploited by respiratory pathogens to facilitate disease transmission. Microbial components or infection-induced inflammatory mediators can directly interact with sensory nerve receptors to induce a cough response. Analysis of cough-generated aerosols and transmission studies have further demonstrated how infectious disease is spread through coughing. This review summarizes the neurophysiology of cough, cough induction by respiratory pathogens and inflammation, and cough-mediated disease transmission.

Development and validation of a nomogram for predicting Mycoplasma pneumoniae pneumonia in adults

The study aimed to explore predictors of Mycoplasma pneumoniae pneumonia (MPP) in adults and develop a nomogram predictive model in order to identify high-risk patients early. We retrospectively analysed the clinical data of a total of 337 adult patients with community-acquired pneumonia (CAP) and divided them into MPP and non-MPP groups according to whether they were infected with MP. Univariate and multivariate logistic regression analyses were used to screen independent predictors of MPP in adults and to developed a nomogram model. Receiver operating characteristic (ROC) curve, calibration curve, concordance index (C-index), and decision curve analysis (DCA) were used for the validation of the evaluation model. Finally, the nomogram was further evaluated by internal verification. Age, body temperature, dry cough, dizziness, CRP and tree-in-bud sign were independent predictors of MPP in adults (P < 0.05). The nomogram showed high accuracy with C-index of 0.836 and well-fitted calibration curves in both the training and validation sets. The area under the receiver operating curve (AUROC) was 0.829 (95% CI 0.774-0.883) for the training set and 0.847 (95% CI 0.768-0.925) for the validation set. This nomogram prediction model can accurately predict the risk of MPP occurrence in adults, which helps clinicians identify high-risk patients at an early stage and make drug selection and clinical decisions.

Comprehensive virome analysis of the viral spectrum in paediatric patients diagnosed with Mycoplasma pneumoniae pneumonia

Background

Among hospitalized children suffering from community-acquired pneumonia, Mycoplasma pneumoniae (MP) is one of the most common pathogens. MP often exists as a co-infection with bacteria or viruses, which can exacerbate the clinical symptoms. We investigated the pathogen spectrum in MP-positive and MP-negative samples from hospitalized children with respiratory tract infections in Beijing, China.

Method

This study included 1038 samples of nasopharyngeal aspirates obtained between April, 2017 and March, 2018 from hospitalized children under 6 years of age with respiratory tract infections. To explore the impact of MP infection on the composition of the pathogen spectrum, 185 nasopharyngeal aspirates (83 MP-positive/102 MP-negative) were randomly selected for next-generation sequencing and comprehensive metagenomics analysis. Real-time PCR was used to detect and verify common respiratory viruses.

Results

Of the 1038 samples, 454 (43.7%) were infected with MP. In children < 6 years of age, the MP infection rate gradually increased with age, with the highest rate of 74.2% in 5–6-year-olds. The results of metagenomics analysis revealed 11 human, animal and plant virus families, and bacteriophages, including common respiratory viruses, enteroviruses and anelloviruses. The virus family with the highest number of reads in both MP-positive and MP-negative samples was the Pneumoviridae, and the number of reads for human respiratory syncytial virus (HRSV) in MP-positive samples was higher than that in MP-negative samples. Among the 83 MP-positive samples, 47 (56.63%) were co-infected with viruses, the most common of which was influenza virus (IFV). The durations of hospitalization and fever were higher in patients with MP co-infection than MP single infection, but the difference was not statistically significant.

Conclusion

The viral family with the highest number of reads in both groups was Pneumoviridae, and the number of reads matched to HRSV in MP-positive samples was much higher than MP-negative samples. Co-infection of MP and IFV infection were the most cases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12985-022-01914-y.

Development of a model for early differentiation of adenovirus pneumonia from Mycoplasma pneumoniae pneumonia

BACKGROUND

Adenovirus pneumonia (AVP) and Mycoplasma pneumoniae pneumonia (MPP) have similar clinical manifestations such as a high prevalence of lung consolidation, making the differential diagnosis difficult before the etiology is reported. This study aimed to compare AVP and MPP, and to build a predictive model to differentiate them early.

METHODS

We selected 198 cases of AVP and 876 cases of MPP. Clinical manifestations, computed tomography (CT) features, and biomarkers were compared. A logistic regression model was built to predict AVP. The area under the curve (AUC) of the receiver-operating characteristic was calculated to evaluate the discriminant ability of the prediction model.

RESULTS

Patients in the AVP group were mainly infants and toddlers, while the MPP group had more pre-school age children. The rate of hypoxemia and severe pneumonia was 3- and 11-times higher, respectively, in the AVP group than in the MPP group (5.6% vs. 1.8%, 27.8% vs. 2.5%, P<0.01). The proportion of patients with a Pediatric Logistic Organ Dysfunction-2 score ≥2 was 10 times higher in the AVP group than in the MPP group (17.4% vs. 1.7%, P<0.01). Bilateral pneumonia was present in 90.2% of the AVP group. Biomarkers, such as interleukin (IL)-2 receptor, IL-10 and lactic dehydrogenase (LDH), were considerably higher in the AVP group than in the MPP group (P<0.01). The predictive model included eight variables, namely: age, severe pneumonia, bilateral pneumonia, ground-glass attenuation, consolidation, atelectasis, C-reactive protein, and LDH. The AUC was 86.6%.

CONCLUSIONS

Compared with MPP, AVP affects younger children, presents a more severe respiratory tract involvement, results in a larger range of lung lesions, and is associated with higher inflammatory biomarkers. Our predictive model includes a combination of clinical features, imaging findings, and biomarkers. It may help pediatricians in the early differentiation of AVP from MPP.

Clinical Usefulness of Serum Lactate Dehydrogenase Levels in Mycoplasma pneumoniae Pneumonia in Children

OBJECTIVE

To elucidate the clinical usefulness of lactate dehydrogenase (LDH) levels in children with Mycoplasma pneumoniae (MP) pneumonia and identify cut-off levels in various clinical conditions.

METHODS

The study was retrospectively performed in 145 children who were hospitalized with MP pneumonia. Laboratory findings, including LDH levels at admission and clinical features were retrospectively reviewed from patients' electronic medical records.

RESULTS

The mean age of the study population was 5.9 y, and the mean value of LDH was 809.7 U/L. Poor response to treatment for MP pneumonia, respiratory virus coinfection, severe MP pneumonia, development of postinfectious bronchiolitis obliterans (PIBO) after MP pneumonia, pleural effusion, and oxygen need during illness were significantly associated with serum LDH levels. The cutoff levels of LDH for predicting poor response to treatment for MP pneumonia and respiratory virus coinfection were 1058 U/L [area under the curve (AUC), 0.729] and 803 U/L (AUC, 0.682), respectively. Those for pneumonic lesions involving at least one-third of the total lung volume, prediction of PIBO development, and extrapulmonary manifestations were 1098 U/L (AUC, 0.715), 676 U/L (AUC, 0.714), and 859 U/L (AUC, 0.710), respectively. The cutoff levels for pleural effusion during illness and for the prediction of oxygen need were 894 U/L (AUC, 0.699) and 1114 U/L (AUC, 0.771), respectively.

CONCLUSION

LDH levels are elevated in diverse clinical conditions in children with MP pneumonia and may be useful in the identification of severe clinical courses of MP pneumonia in children.

Clinical analysis of the epidemiology and changes in inflammatory indexes of Mycoplasma pneumonia in acute and recovery stage pediatric patients

BACKGROUND

As Mycoplasma pneumoniae pneumonia (MPP) is on the rise in children and adolescents, this work explored the clinical analysis of epidemiological and inflammatory changes in children with MPP during the acute and convalescent phases, and analyzed their relationship with clinical manifestations.

METHODS

One hundred and twenty MP patients (experimental group) and 100 healthy children (control group) were selected as the research objects. Enzyme-linked immunosorbent assay (ELISA) was used to detect the changes in tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-10 (IL-10) and procalcitonin (PCT).

RESULTS

The proportion of children aged 3-7 years was significantly higher than that of other age groups (0-1, 1-3, and 7-14 years old) (P<0.05). The serum levels of TNF-α, IL-6, IL-8, IL-10, and PCT in children with MP were significantly higher than those in the control group (P<0.05). Changes in pulmonary fibrosis and serum and pleural fluid TNF-α, IL-6, IL-8, IL-10, and PCT concentrations on chest X-ray and computed tomography (CT) in children with MP with pleural effusion significantly higher than that in children without pulmonary fibrosis (P<0.05).

CONCLUSIONS

MPP was more common in children aged 3-7 years. In addition, the changes of inflammatory markers TNF-α, IL-6, IL-8, IL-10, and PCT in serum and pleural effusion of children with MP were of great value for the diagnosis, treatment, and prognosis of the disease.

Mycoplasma pneumoniae among Hospitalized Patients with Acute Respiratory Tract Infections in an Indian Tertiary Care Hospital: an Underreported Health Problem

The epidemiology of Mycoplasma pneumoniae (Mp) is poorly understood in India. The present study was conducted to identify the prevalence of Mp in a large set of patients with acute respiratory tract infections (ARI) in an Indian tertiary hospital. During 2015-2020, we tested throat swab specimens from patients with the clinical diagnosis of ARI (n = 1,098) by a real-time PCR and compared the demographic, clinical, laboratory, and outcome data of Mp-positive and Mp-negative patients. During the study period, 5% (55/1,098) of the tested samples were positive for Mp by PCR. School-aged children and young adults represented 36% (20/55) of the cases and 47.3% (26/55) of the cases were registered during the summer and monsoon. Among the Mp-positive patients, 61.8% (34/55) had underlying conditions; the most common were malignancy (n = 12; 21.8%) and hypertension (n = 6; 10.9%). Fever (98.2% versus 84.9%; P = 0.006), and pharyngitis (27.3% versus 16.3%; P = 0.034) were significantly common in the Mp-positive group than Mp-negative group. Among the Mp-positive group, 20% (11/55) of patients were admitted to an intensive care unit and a total of 7/55 (12.7%) patients received ventilatory support. The mortality in the Mp-positive cohort was 13.3%. The study provides baseline data regarding Mp prevalence and clinical characteristics. The application of molecular assays for diagnosing this pathogen among hospitalized patients with ARI could reduce inappropriate empirical antibiotic treatment and improve patient outcomes. Further large-scale studies are required to avoid the underdiagnosis of Mp infections in India and such studies should address some research gaps, such as macrolide resistance and molecular typing. IMPORTANCE M. pneumoniae (Mp) is a significant pathogen causing atypical pneumonia but by far these infections are underreported clinical entities in India. In the present study, we report the prevalence of Mp and describe the demographic and baseline clinical data of Mp-positive cases in an Indian tertiary care hospital. Our study may improve the clinician's awareness of this important agent of respiratory infection therefore timely and accurate diagnostic tools can be applied for patient management decisions and outcomes.

Pinocembrin Relieves Mycoplasma pneumoniae Infection‑Induced Pneumonia in Mice Through the Inhibition of Oxidative Stress and Inflammatory Response

Pneumonia is a serious infectious disease with increased morbidity and mortality worldwide. The M. pneumoniae is a major airway pathogen that mainly affects respiratory tract and ultimately leads to the development of pneumonia. The current exploration was aimed to uncover the beneficial properties of pinocembrin against the M. pneumoniae-triggered pneumonia in mice via its anti-inflammatory property. The pneumonia was stimulated to the BALB/c mice via infecting them with M. pneumoniae (100 µl) for 2 days through nasal drops and concomitantly treated with pinocembrin (10 mg/kg) for 3 days. The azithromycin (100 mg/kg) was used as a standard drug. Then the lung weight, nitric oxide, and myeloperoxidase (MPO) activity was assessed. The content of MDA, GSH, and SOD activity was scrutinized using kits. The total cells and DNA amount present in the bronchoalveolar lavage fluid (BALF) was assessed by standard methods. The IL-1, IL-6, IL-8, TNF-α, and TGF contents in the BALF samples and NF-κB level in the lung tissues were assessed using kits. The lung histopathology was assessed microscopically to detect the histological alterations. The 10 mg/kg of pinocembrin treatment substantially decreased the lung weight, nitric oxide (NO) level, and MPO activity. The MDA level was decreased, and GSH content and SOD activity were improved by the pinocembrin treatment. The pinocembrin administered pneumonia animals also demonstrated the decreased total cells, DNA amount, IL-1, IL-6, IL-8, TNF-α, and TGF in the BALF and NF-κB level. The findings of histological studies also witnessed the beneficial role of pinocembrin against M. pneumoniae-infected pneumonia. In conclusion, our findings confirmed that the pinocembrin effectively ameliorated the M. pneumoniae-provoked inflammation and oxidative stress in the pneumonia mice model. Hence, it could be a hopeful therapeutic agent to treat the pneumonia in the future.

Refractory Mycoplasma pneumoniae Pneumonia in Children: Early Recognition and Management

Refractory Mycoplasma pneumoniae pneumonia (RMPP) is a severe state of M. pneumoniae infection that has attracted increasing universal attention in recent years. The pathogenesis of RMPP remains unknown, but the excessive host immune responses as well as macrolide resistance of M. pneumoniae might play important roles in the development of RMPP. To improve the prognosis of RMPP, it is mandatory to recognize RMPP in the early stages, and the detection of macrolide-resistant MP, clinical unresponsiveness to macrolides and elevated proinflammatory cytokines might be clues. Timely and effective anti-mycoplasmal therapy and immunomodulating therapy are the main strategies for RMPP.

A systematic review of the clinical features of pneumonia in children aged 5-9 years: Implications for guidelines and research

Background

Childhood pneumonia presents a large global burden, though most data and guidelines focus on children less than 5 years old. Less information is available about the clinical presentation of pneumonia in children 5-9 years of age. Appropriate diagnostic and treatment algorithms may differ from those applied to younger children. This systematic literature review aimed to identify clinical features of pneumonia in children aged 5-9 years, with a focus on delineation from other age groups and comparison with existing WHO guidance for pneumonia in children less than 5 years old.

Methods

We searched MEDLINE, EMBASE and PubMed databases for publications that described clinical features of pneumonia in children 5-9 years old, from any country with no date restriction in English. The quality of included studies was evaluated using a modified Effective Public Health Project Practice (EPHPP) tool. Data relating to research context, study type, clinical features of pneumonia and comparisons with children less than 5 years old were extracted. For each clinical feature of pneumonia, we described mean percentage (95% confidence interval) of participants with this finding in terms of aetiology (all cause vs Mycoplasma pneumoniae), and method of diagnosis (radiological vs clinical).

Results

We included 15 publications, eight addressing all-cause pneumonia and seven addressing Mycoplasma pneumoniae. Cough and fever were common in children aged 5-9 years with pneumonia. Tachypnoea was documented in around half of patients. Dyspnoea/difficulty breathing and chest indrawing were present in approximately half of all-cause pneumonia cases, with no data on indrawing in the outpatient setting. Chest and abdominal pain were documented in around one third of cases of all-cause pneumonia, based on limited numbers. In addition to markers of pneumonia severity used in children <5 years, pallor has been identified as being associated with poorer outcomes alongside comorbidities and nutritional status.

Conclusions

Quality research exploring clinical features of pneumonia, treatment and outcomes in children aged 5-9 years using consistent inclusion criteria, definitions of features and age ranges are urgently needed to better inform practice and guidelines. Based on limited data fever and cough are common in this age group, but tachypnoea cannot be relied on for diagnosis. While waiting for better evidence, broader attention to features such as chest and abdominal pain, the role of chest radiographs for diagnosis in the absence of symptoms such as tachypnoea, and risk factors which may influence patient disposition (chest indrawing, pallor, nutritional status) warrant consideration by clinicians.

Protocol registration

PROSPERO: CRD42020213837.

Epidemiological Study on Mycoplasma pneumoniae and Chlamydia pneumoniae Infection of Hospitalized Children in a Single Center During the COVID-19 Pandemic

Background

Since the outbreak of COVID-19, a series of preventive and control measures in China have been used to effectively curb the spread of COVID-19. This study aimed to analyze the epidemiological characteristics of Mycoplasma pneumoniae (MP) and Chlamydia pneumoniae (CP) in hospitalized children with acute respiratory tract infection during the COVID-19 pandemic.

Methods

MP IgM antibody and CP IgM antibody were detected in all hospitalized children due to acute respiratory tract infection in the Children’s Hospital Affiliated to Zhejiang University from January 2019 to December 2020. These data were compared between 2019 and 2020 based on age and month.

Results

The overall detection rate of MP and CP in 2020 was significantly lower than that in 2019 (MP: 21.5% vs 32.9%, P<0.001; CP: 0.3% vs 0.9%, P<0.001). This study found a 4-fold reduction in the number of children positive for MP and a 7.5-fold reduction in the number of children positive for CP from 2019 to 2020. The positive cases were concentrated in children aged >1 year old. In 2019, the positive rate of MP was detected more commonly in children 3 years of age or older than in younger children. In 2020, the higher positive rate of MP reached a peak in the 3- to 6-year age group (35.3%). CP was detected predominantly in children aged 6 years older in 2019 and 2020, with positive rates of 4.8% and 2.6%, respectively. Meanwhile, the positive rates of MP in 2019 were detected more commonly in July, August and September, with 47.2%, 46.7% and 46.3%, respectively. Nevertheless, the positive rates of MP from February to December 2020 apparently decreased compared to those in 2019. The positive rates of CP were evenly distributed throughout the year, with 0.5%-1.6% in 2019 and 0.0%-2.1% in 2020.

Conclusions

A series of preventive and control measures for SARS-CoV-2 during the COVID-19 pandemic can not only contain the spread of SARS-CoV-2 but also sharply improve the infection of other atypical pathogens, including MP and CP.

Geraniol relieves mycoplasma pneumonia infection-induced lung injury in mice through the regulation of ERK/JNK and NF-κB signaling pathways

BACKGROUND

Pneumonia is a serious pediatric lung injury disease caused by Mycoplasma pneumoniae (M. pneumoniae) with increasing global prevalence every year. The WHO has reported that nearly 19% of children die due to pneumonia worldwide.

OBJECTIVE

The present research was conducted to discover the ameliorative properties of geraniol against M. pneumoniae-provoked pneumonia in mice through the modulation of inflammatory responses.

METHODOLOGY

The pneumonia was provoked in the male Swiss albino mice via infecting animals with 100 µl of M. pneumoniae for 2 days and supplemented concurrently with 20 mg/kg of geraniol for 3 days. 100 mg/kg of azithromycin was used as a standard drug. The nitric oxide (NO) level and MPO activity were measured using kits. The SOD activity, GSH, and MDA levels were studied using standard methods. The polymerase chain reaction (PCR) study was performed to examine the M. pneumoniae DNA load. The inflammatory cytokines status was assessed by assay kits. The ERK1/2, JNK1/2, and NF-κB expressions were studied by reverse-transcription (RT-PCR). The lung tissues were analyzed microscopically to investigate the histological alterations.

RESULTS

Geraniol treatment effectively reduced lung weight, NO level, and MPO activity in the pneumonia mice. The total cells and M. pneumoniae DNA load were also decreased by the geraniol. The SOD activity and GSH level were improved and MDA was decreased by the geraniol treatment. The IL-1, IL-6, IL-8, TNF-α, and TGF status were appreciably depleted by the geraniol in the pneumonia mice. Geraniol also suppressed the ERK1/2 and NF-κB expressions in the lung tissues. Histological findings also suggest the therapeutic roles of geraniol against pneumonia in mice.

CONCLUSION

In summary, our results proved the beneficial roles of geraniol against the M. pneumoniae-provoked pneumonia. Geraniol could be a hopeful therapeutic agent to treat pneumonia in the future.

Development of a Nomogram for Predicting Refractory Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

In children, refractory Mycoplasma pneumoniae pneumonia (RMPP) may result in severe complications and high medical costs. There is research on a simple and easy-to-use nomogram for early prediction and timely treatment of RMPP.

METHODS

From December 2018 to June 2021, we retrospectively reviewed medical records of 299 children with Mycoplasma pneumoniae pneumonia (MPP) hospitalized in Tianjin Children's Hospital. According to their clinical manifestations, patients were divided into the RMPP group and the general Mycoplasma pneumoniae pneumonia (GMPP) group. The clinical manifestations, laboratory indicators, and radiological data of the two groups were obtained. Stepwise regression was employed for variable selection of RMPP. The predictive factors selected were used to construct a prediction model which presented with a nomogram. The performance of the prediction model was evaluated by C statistics, calibration curve, and receiver operating characteristic (ROC) curve.

RESULTS

The RMPP group significantly showed a higher proportion of females, longer fever duration, and longer hospital stay than the GMPP group (P < 0.05). Additionally, the RMPP group revealed severe clinical characteristics, including higher incidences of extrapulmonary complications, decreased breath sounds, unilateral pulmonary consolidation >2/3, and plastic bronchitis than the GMPP group (P < 0.05). The RMPP group had higher neutrophil ratio (N%), C-reactive protein (CRP), interleukin-6 (IL-6), lactic dehydrogenase (LDH), and D-dimer than the GMPP group (P < 0.05). Stepwise regression demonstrated that CRP [OR = 1.075 (95% CI: 1.020-1.133), P < 0.001], LDH [OR = 1.015 (95% CI: 1.010-1.020), P < 0.001], and D-dimer [OR = 70.94 (95% CI: 23.861-210.904), P < 0.001] were predictive factors for RMPP, and developed a prediction model of RMPP, which can be visualized and accurately quantified using a nomogram. The nomogram showed good discrimination and calibration. The area under the ROC curve of the nomogram was 0.881, 95% CI (0.843, 0.918) in training cohorts and 0.777, 95% CI (0.661, 0.893) in validation cohorts, respectively.

CONCLUSION

C-reactive protein, LDH, and D-dimer were predictive factors for RMPP. The simple and easy-to-use nomogram assisted us in quantifying the risk for predicting RMPP, and more accurately and conveniently guiding clinicians to recognize RMPP, and contribute to a rational therapeutic choice.

Pulmonary and Extrapulmonary Manifestations in Hospitalized Children with Mycoplasma Pneumoniae Infection

Mycoplasma pneumoniae (MP) is one of the main causes of both upper and lower respiratory infections in school-aged children, accounting for up to 40% of community-acquired pneumonia. Younger children are also affected, and extrapulmonary manifestations have been recently reported in the pediatric population. We carried out a retrospective analysis of MP-positive patients admitted to the Pediatric Emergency Unit of S. Orsola Malpighi University Hospital in Bologna, the largest tertiary pediatric referral center in the Emilia–Romagna region, Northern Italy, between 2012 and 2020. We identified 145 patients with MP infection (82 males and 63 females), 27% of which were younger than 2 years; the median age was 5 years (interquartile range 1–9). The clinical presentation partially differed between age groups. School-aged children were more likely to have a chest X-ray-confirmed pneumonia (p = 0.013), while younger children required oxygen therapy more often (p = 0.048). Seventy-four children (51%) showed extrapulmonary manifestations, mainly gastrointestinal (30%) and dermatological (14%). Neurological symptoms were more frequent in children older than 6 years (p = 0.006). The rate of other extrapulmonary manifestations did not differ significantly between age groups. This study shows that MP infection is a frequent cause of pediatric hospitalization, including of children younger than 2 years. Clinicians should be aware of the variable clinical expressions of MP, including extrapulmonary manifestations, to achieve a correct diagnosis and determine appropriate treatment.

Pediatric Lower Respiratory Tract Infections: Imaging Guidelines and Recommendations

Lower respiratory tract infection (LRTI) remains a major cause of morbidity and mortality in children. Various organisms cause LRTI, including viruses, bacteria, fungi, and parasites, among others. Infections caused by 2 or more organisms also occur, sometimes enhancing the severity of the infection. Medical imaging helps confirm a diagnosis but also plays a role in the evaluation of acute and chronic sequelae. Medical imaging tests help evaluate underlying pathology in pediatric patients with recurrent or long-standing symptoms as well as the immunocompromised.

Mechanism of Infantile Feire Kechuan Oral Solution against Mycoplasma pneumoniae infection of A549 cells

BACKGROUND

Mycoplasma pneumoniae is a leading cause of community-acquired respiratory infections. Infantile Feire Kechuan Oral Solution (IFKOS) is effective for treatment of M. pneumoniae infection. The aim of this study was to explore the potential mechanism of IFKOS against M. pneumoniae infection in basal epithelial human lung adenocarcinoma A549 cells.

METHODS

The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to determine the effects of IFKOS on the viability of A549 cells infected with M. pneumoniae. Optical microscopy was used to observe cell morphology and a Muse cell analyzer was used to assess apoptosis and the cell cycle phase. Enzyme-linked immunosorbent assays were employed to assess the expression levels of interleukin (IL)-4, IL-6, IL-8, IL-17, tumor necrosis factor (TNF)-α, interferon (IFN)-α, and IFN-γ.

RESULTS

Under certain conditions, M. pneumoniae infection reduced the viability and inhibited the proliferation of A549 cells, promoted early apoptosis, and arrested cells in the G0/G1 phase, thus shortening the S and G2/M phases (all p < 0.05). M. pneumoniae also upregulated expression of IL-8 and TNF-α and downregulated that of IL-6 (p < 0.05), which switched the immune balance of Th1/Th2 to Th1 cells. IFKOS (5.531 mg/mL) improved the viability and proliferation of M. pneumoniae-infected A549 cells, mitigated early apoptosis, and reversed cell cycle arrest in the G0/G1 phase, thereby extending the S and G2/M phases (all, p < 0.05). IFKOS downregulated expression of IL-8 and TNF-α and upregulated that of IL-6 (p < 0.01), thereby reversing the immune imbalance of Th1/Th2. Secretion of IL-4, IL-17, IFN-α, and IFN-γ was not observed.

CONCLUSION

IFKOS played a protective role in the regulation of cell viability, apoptosis, the cell cycle, and Th1/Th2 immune imbalance induced by M. pneumoniae infection and conveyed an anti-inflammatory effect in A549 cells.

Application of CT images based on the optimal atlas segmentation algorithm in the clinical diagnosis of Mycoplasma Pneumoniae Pneumonia in Children

Objective

Use of optimal Atlas segmentation algorithm to study the imaging signs of mycoplasma pneumonia with multi-slice spiral CT (HRCT), and to explore the value of HRCT in the diagnosis and efficacy in evaluation of mycoplasma pneumonia in children.

Methods

The study retrospectively analyzed 72 patients diagnosed with mycoplasma pneumonia in our hospital from January 2017 to January 2019. The imaging data and clinical data of 72 patients were collected. The optimal Atlas segmentation algorithm was used to analyze the characteristics of CT examination, and the value of CT in the diagnosis of mycoplasma pneumonia and the evaluation of curative effect was summarized.

Results

Among all patients, 37 cases were unilateral lesions, 35 cases were bilateral lesions, 19 cases were in the left upper lobe, 24 cases were in the left lower lobe, 21 cases were in the right upper lobe, 13 cases were in the right middle lobe, 25 The lesion was located in the right lower lobe. The main CT findings of the lesions before treatment were large patchy, spot-shaped shadows, and strip-shaped or ground-glass shadows. After treatment, the main CT findings of the lesions were reduced lesion density and reduced lesion range.

Conclusion

CT can clearly show the pulmonary lesions of mycoplasma pneumonia, and its unique imaging signs can improve the clinical diagnosis accuracy. In addition, CT scans can evaluate the treatment effect according to the changes in the characteristics of the lesion, which has important value for the evaluation of the effect for clinical diagnosis and efficacy evaluation of mycoplasma pneumonia.

Serum sTREM-1 and CXCL-16 Levels in Children with Mycoplasma pneumoniae Pneumonia and Their Diagnostic Value

Mycoplasma pneumoniae pneumonia (MPP) is an acute respiratory tract infection caused by Mycoplasma pneumoniae. It is characterized by severe symptoms, long course of disease, many intrapulmonary complications, and poor therapeutic effect. In recent years, the incidence of Mycoplasma infection have been gradually rising trend, and the children's own immune system development is not mature, cases differences, children with mild can only show the upper respiratory tract infection, and critically ill children can lead to lung infection and even lead to multiple organ dysfunction, affect life and health of children. Soluble triggering receptors expressed on myeloid cell-1 (sTREM-1) is a subtype secreted by myeloid cell trigger receptor-1, which is released into blood in large amounts when the body is infected, and is a newly discovered inflammatory indicator in recent years. CXC chemokine 16 (CXCL-16) can recruit lymphocytes by chemotaxis through binding to its receptor CXCR6 to participate in the body's immune regulation. The purpose of this study was to investigate serum sTREM-1 and CXCL-16 levels in children with MPP and to analyze their correlation with the disease and diagnostic value. The results showed that the serum levels of sTREM-1 and CXCL-16 were increased in children with Mycoplasma. Serum levels of sTREM-1 and CXCL-16 were positively correlated with the severity of the disease. sTREM-1 combined with CXCL-16 has an important value in the diagnosis of children with MPP.

Increasing Age Affected Polymorphonuclear Neutrophils in Prognosis of Mycoplasma pneumoniae Pneumonia

Purpose

It is well known that age is related to the incidence of Mycoplasma pneumoniae pneumonia (MPP), and how age and other factors contribute to MPP remains unclear. In this study, we investigate how age affects the prognosis of MPP.

Patients and Methods

A total number of 1875 hospitalized children with pneumonia were enrolled in this study, including 52 children with refractory M. pneumoniae pneumonia (RMPP) and 298 children with non-RMPP. We used multiple logistic regression analysis to further identify the risk factors of RMPP, and found that age and polymorphonuclear neutrophils (PMNs) count were the key independent risk factors for the occurrence of RMPP. In order to improve specificity, 4.5 years old was taken as the cut-off value. Then, according to the cut-off value of age, 76 participants were recruited and divided into four groups: <4.5y MPP group, ≥4.5y MPP group, <4.5y health control (<4.5yHC) and ≥4.5y HC group. We explored the diverse functions of primary PMNs from children of different ages with MPP at cellular level. Besides, we studied the relationship between lung injury and PMNs in mice model with MPP of different ages.

Results

We found that the age and PMNs count of RMPP group were significantly higher than those of the non-RMPP group. Importantly, there is a linear correlation between the age of patients with RMPP and the percentage of PMNs. Further analysis showed that elderly patients infected with M. pneumoniae had more active PMNs function. Meanwhile, proteomics showed that children with M. pneumoniae infection in different age groups have differences in PMNs apoptosis, nicotinamide adenine dinucleotide phosphate, mitochondrial function and oxidative stress. Finally, we found that age is also involved in the pathogenesis of mouse model with MPP.

Conclusion

We speculate that age may contribute to the development of RMPP.

Prevalence, risk factors and outcome of Mycoplasma pneumoniae infection among children in Uganda: a prospective study

BACKGROUND

: Atypical bacteria cause 10-40% of all childhood pneumonia.. Data on the burden of atypical pneumonia in sub-Saharan Africa are limited.

AIM

: To determine the prevalence, associated factors, and outcome of Mycoplasma pneumoniae infection in children with respiratory symptoms at Mulago National Referral Hospital, Kampala.

METHODS

: Children aged 2 months to 12 years with cough and/or difficult breathing and fast breathing were recruited. A clinical history and physical examination were undertaken. Blood samples for Mycoplasma pneumoniae IgM antibodies were taken at enrolment and Day 21 and induced sputum for DNA-PCR. Admitted participants were followed for a maximum of 7 days or until discharge or death, whichever came first.

RESULTS

: A total of 385 children were enrolled, and, of these, 368 (95.6%) were <5 years. Overall, 60/385 (15.6%) participants tested positive for M. pneumoniae IgM and/or DNA-PCR. Of these, 56/60 (93.3%) were <5 years of age. Wheezing was present in 21/60 (35.0%) of the children with atypical pneumonia and in 128/325 (39.4%) with typical pneumonia. The factors associated with M. pneumonia were female sex (AOR 1.94, 95% CI 1.22-3.08, p < 0.001), age ≥12 months (AOR 2.73, 95% CI 1.53-4.87, p = 0.01) and a history of prematurity (AOR 2.07, 95% CI 1.23-3.49, p = 0.01). Mortality was 17/352 (4.8%) and, of these, 4/17 (23.5%) had M. pneumonia.

CONCLUSION

: M. pneumonia is common in young children , especially females above 2 years and those with history of prematurity. It presents with severe symptoms. The results of the study highlight the importance of considering atypical bacteria in under-5s with the symptoms of pneumonia.

Expression of Serum miR-155 in Children with Mycoplasma pneumoniae Pneumonia and Its Role in Immunity to Mycoplasma pneumoniae

Objective

To investigate the expression of serum miR-155 in children with Mycoplasma pneumoniae pneumonia (MPP).

Methods

A total of 100 children at our hospital with pneumonia caused by Mycoplasma pneumoniae infection were enrolled as a study group, including 45 cases in the acute phase (acute phase group) and 55 in the recovery phase (recovery phase group). An additional 30 healthy children were enrolled during the same period as the control group. The expression levels of miR-155, tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8), IL-10, IL-13, immunoglobulin (Ig) G, IgA, complements (C3 and CH50), and T lymphocyte subsets (CD₃⁺, CD₄⁺, CD₈⁺, and CD₄⁺/CD₈⁺) were determined. Multivariate logistic regression analysis was performed to identify risk factors affecting MPP in children.

Results

miR-155, IL-10, IgG, IgA, CD₃⁺, CD₄⁺, and CD₄⁺/CD₈⁺ were poorly expressed in children with MPP, and their expression in the acute phase group was significantly lower than that in the recovery phase group. TNF-α, IL-13, C3, and CH50 were highly expressed in the children, and their expression was significantly higher in the acute  phase group than in the recovery phase group. In the acute phase group, the expression of IL-8 was significantly higher than that in the control and recovery phase groups but without any significant differences between the recovery phase and control groups. Age, season, low complement state, epidemiological contact history, and antibiotic use time were independent risk factors affecting MPP in children.

Conclusion

Serum miR-155 is poorly expressed in children with MPP, and it can regulate inflammatory disorders and immune responses.

Evaluation of the CARDS toxin and its fragment for the serodiagnosis of Mycoplasma pneumoniae infections

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen in community-acquired pneumonia. The community-acquired respiratory distress syndrome (CARDS) toxin is the only known virulence factor of M. pneumoniae. It is worth exploring whether this toxin can be used as a candidate antigen for the serodiagnosis of M. pneumoniae. In this study, the full-length, N-terminal, and C-terminal regions of the CARDS toxin were expressed and purified, and serological reactions were evaluated using ELISA. A total of 184 serum samples were collected and tested using a commercialized test kit. Eighty-seven samples were positive, and 97 samples were negative for infection. The purified recombinant proteins were used as antigens to test the serum via indirect ELISA. The sensitivity of the CARDS toxin, the N-terminal region, and the C-terminal region were 90.8%, 90.8%, and 92.0%, respectively. The specificity of the CARDS toxin, the N-terminal region, and the C-terminal region were 85.6%, 73.2%, and 93.8%, respectively. All three CARDS toxin proteins exhibited good reactivity, of which the C-terminal region had a good discrimination ability in human sera. This may have a potential diagnostic value for M. pneumoniae infections.

Prevalence and clinical characteristics of hospitalized children with community-acquired Mycoplasma pneumoniae pneumonia during 2017/2018, Chengde, China

Community acquired-pneumonia (CAP) has varying causative pathogens and clinical characteristics. This study investigated the prevalence of Mycoplasma pneumoniae (M pneumoniae) and evaluated the clinical characteristics in infected hospitalized children by disease severity.From throat swabs of hospitalized children (5 months to 14 years) with CAP collected between November 2017 and May 2018, M pneumoniae and other CAP pathogens were identified using polymerase chain reaction (PCR). Differences in clinical and laboratory test data were compared between severe and mild case groups.Of 333 hospitalized children enrolled, 221/333 (66.4%) tested positive for M pneumoniae and 24/221 (10.9%) patients were (n = 9, aged <5 years vs n = 15, ≥5 years) single infection by PCR, however, only 170/333 (51.1%) patients were presented with M pneumoniae IgM-positive. M pneumoniae detection rate by PCR was higher than by immunoglobulin (IgM) serology. In 123/221 (55.7%) M pneumoniae infected patients, coinfection with bacterial pathogens (n = 61, <5 years vs n = 62, ≥5 years) occurred. Children (aged 3-8 years) had most M pneumoniae infection. Severe M pneumoniae pneumonia (MPP) in children occurred mostly in older age (7 [interquartile ranges {IQR}, 6-8] years; P < .0001), with longer cough days (14 [IQR, 10-19.5] days; P = .002) and hospitalization duration (9.5 [IQR, 7-12.3] days; P < .0001), lower lymphocyte ratio (24.1, [IQR, 20.0-31.1] %; P = .001), higher neutrophils ratio (66.0, [IQR, 60.2-70.3]%; P < .0001), and serum C-reactive protein (CRP) level (3.8, [IQR, 1.3-10.9] mg/L; P = .027).M pneumoniae is the most commonly detected pathogen in CAP. High coinfection prevalence increases diagnosis difficulty by clinically nonspecific characteristics. M pneumoniae detection by PCR with IgM may improve precise and reliable diagnosis of community-acquired MPP.

Mycoplasma pneumoniae may cause dyspnoea and hospitalisations in young healthy adults

Polymerase chain reaction (PCR)-based diagnostics for Mycoplasma pneumoniae (M. pneumoniae) from the respiratory tract has become widely available, but the interpretation of the results remains unclear. M. pneumoniae has been suggested to cause mainly mild and self-limiting infections or asymptomatic carriage. However, systematic analyses of the association between PCR results and clinical findings are scarce. This study aimed to clarify the clinical features of PCR-positive M. pneumoniae infections in a hospital setting. We reviewed 103 PCR-positive patients cared for in a university hospital during a 3-year period. Data on age, sex, health condition, acute symptoms, other pathogens found, laboratory and X-ray results and treatments were collected. Over 85% of the patients had a triad of typical symptoms: fever, cough and shortness of breath. Symptoms in the upper respiratory tract were rare. In 91% of the cases, M. pneumoniae was the only pathogen found. The highest incidence was found in the age group of 30–40 years, and 68% of the patients did not have any underlying diseases. Most patients were initially empirically treated with beta-lactam antibiotics and needed 2–4 changes in their treatment. Only 6% were discharged without an antibiotic effective against M. pneumoniae. This study shows that M. pneumoniae often led to hospitalisation and that patients needed appropriate antimicrobial treatment to recover. Mixed infections were rare, and situations that could be interpreted as carriage did not occur.

Mycoplasma pneumoniae Infections: Pathogenesis and Vaccine Development

Mycoplasma pneumoniae is a major causative agent of community-acquired pneumonia which can lead to both acute upper and lower respiratory tract inflammation, and extrapulmonary syndromes. Refractory pneumonia caused by M. pneumonia can be life-threatening, especially in infants and the elderly. Here, based on a comprehensive review of the scientific literature related to the respective area, we summarize the virulence factors of M. pneumoniae and the major pathogenic mechanisms mediated by the pathogen: adhesion to host cells, direct cytotoxicity against host cells, inflammatory response-induced immune injury, and immune evasion. The increasing rate of macrolide-resistant strains and the harmful side effects of other sensitive antibiotics (e.g., respiratory quinolones and tetracyclines) in young children make it difficult to treat, and increase the health risk or re-infections. Hence, there is an urgent need for development of an effective vaccine to prevent M. pneumoniae infections in children. Various types of M. pneumoniae vaccines have been reported, including whole-cell vaccines (inactivated and live-attenuated vaccines), subunit vaccines (involving M. pneumoniae protein P1, protein P30, protein P116 and CARDS toxin) and DNA vaccines. This narrative review summarizes the key pathogenic mechanisms underlying M. pneumoniae infection and highlights the relevant vaccines that have been developed and their reported effectiveness.

Bronchiolitis Associated with Mycoplasma pneumoniae Infection in Infants in Foshan China: An Epidemiologic Study

Background

Bronchiolitis is common in infants under 2 years of age. Most infections are caused by respiratory syncytial virus (RSV), but the importance of Mycoplasma pneumoniae (MP) in the etiology of bronchiolitis is unclear.

Material/Methods

We investigated the clinical characteristics of bronchiolitis caused by MP in 79 infants admitted to Shunde Women’s and Children’s Hospital of Guangdong Medical University and Sanshui Women’s and Children’s Healthcare Hospital from January 2016 to December 2018. Infection with MP was confirmed by the presence of serum immunoglobulin M.

Results

The peak detection rates of MP in the years 2016, 2017, and 2018 were 19.2%, 21.3%, and 24.0%, respectively. In each year, the peak of MP infections occurred during June and July. MP-associated bronchiolitis was mainly seen in infants from 6 to 12 months of age. Compared with RSV-associated bronchiolitis, the age of patients with bronchiolitis associated with MP was significantly older and they had a shorter hospital stay (all P<0.01 or P<0.05).

Conclusions

Our study indicated that MP is an important cause of bronchiolitis, with peaks of occurrence during June and July every year. Pulmonary interstitial infiltration was a characteristic of this infection. Azithromycin treatment can shorten the course of MP-associated bronchiolitis. Investigation of the epidemiological characteristics of pediatric MP-associated bronchiolitis can help diagnose and treat the disease correctly.

Prediction of risk factors of bronchial mucus plugs in children with Mycoplasma pneumoniae pneumonia

Background

Recently, many cases of pneumonia in children with Mycoplasma pneumoniae infection have been shown to have varying degrees of intrabronchial mucus plug formation. The clinical, laboratory, radiological characteristics, and treatment of patients with Mycoplasma infection are analyzed in this study. The risk factors for M. pneumoniae pneumonia (MPP) mucus plug formation in children are explored, and a risk factor scoring system is established.

Methods

MPP patients treated with bronchoscopy were retrospectively enrolled in the study from February 2015 to December 2019. The children were divided into a mucus plug group and a control group according to the presence or absence of mucus plug formation. The clinical, laboratory, radiological characteristics, and treatment of the two groups of children were compared. Univariate and multivariate logistic regression models were used to identify the risk factors for MPP mucus plug formation. The receiver operating characteristic (ROC) curve was drawn to evaluate the regression model and establish the MPP mucous plug risk factor scoring system.

Results

A univariate analysis showed that the children in the mucous group were older and had a longer fever duration, longer hospital stay, higher fever peak, more cases of wheezing symptoms and allergies, and azithromycin or corticosteroids were administered later. In addition, neutrophil, C-reactive protein (CRP), lactate dehydrogenase (LDH), D-dimer (DD), sputum MP-DNA copy number, and total immunoglobulin A (IgA) levels were higher, while prealbumin (PA) levels were lower. The ROC curve analysis showed that children with MPP had PA ≤144.5 mg/L, had used corticosteroids during the course of the illness of ≥4.5 days, CRP ≥12.27 mg/L, an LDH ≥ 462.65 U/L, and there was a possibility of intra-airway mucus formation. The independent risk factors were scored according to their odds ratio (OR) value. Among the 255 children with MPP, the high-risk group had 44 (83.02%) mucus plugs out of 53; the middle-risk group had 35 (34.3%) mucus plugs out of 102; and the low-risk group had 11 (11%) mucus plugs out of 100.

Conclusions

PA levels, timing of corticosteroid use (use in the first few days), CRP levels, and LDH levels were independent risk factors for MPP mucus plug formation. This provides a basis for the early identification of MPP in children combined with mucus plug formation.

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

BACKGROUND

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Severe Mycoplasma pneumoniae pneumonia requiring intensive care in children, 2010-2019

BACKGROUND/PURPOSE

Despite the high prevalence of Mycoplasma pneumoniae infections, reports on severe life-threatening M. pneumoniae pneumonia (MPP) in children are limited.

METHODS

We retrospectively enrolled pediatric patients with PCR-positive MPP requiring ICU admission in a children's hospital in Taipei, Taiwan from Jun 2010 to October 2019. Clinical manifestations and laboratory data of severe MPP were analyzed. Macrolide susceptibility was determined by genotyping, and its relationship with clinical manifestations was also analyzed.

RESULTS

Approximately 5% (34/658) children hospitalized for MPP required ICU admission. Compared with non-ICU cases (n = 291), ICU cases (n = 34) were associated with more underlying conditions, more pleural effusion, longer fever duration, longer hospital stay, the requirement of second-line antibiotic treatment, and delayed effective and second-line antibiotic treatment. Macrolide resistance was similar in ICU and non-ICU groups (53% vs 53%; p = 0.986). In severe MPP, patients requiring endotracheal intubation were associated with more septic shock, empyema, ARDS, prolonged fever after effective antibiotic treatment, delayed second-line and effective antibiotic treatment. In 18 of the 22 patients with pleural fluid analysis, the pleural effusion was alkaline (pH > 7.7) and lymphocyte-predominant.

CONCLUSION

M. pneumoniae infection can cause severe life-threatening pneumonia in children. Delayed effective and second-line antibiotic treatments are associated with severe life-threatening MPP.

Dynamic change of Mycoplasma pneumoniae pneumonia in hospitalized children in a general hospital: a 3-year retrospective analysis

BACKGROUND

The epidemiology and economic burden of hospitalized community-acquired pneumonia (CAP) children due to MP is still poorly understood. This study aimed to investigate the dynamic changes of Mycoplasma pneumoniae pneumonia (MPP) in children in a general hospital.

METHODS

A total of 2011 CAP children aged 1-16 years hospitalized at Peking University Third Hospital from 2017 to 2019 were enrolled by cross-sectional study for the retrospective analysis of the clinical data mainly including seasonal distribution of MPP, hospital stay, severity, complications, use of flexible bronchoscopy, and hospitalization costs. The dynamic changes of CAP and MPP children within 3 consecutive years and the differences between the MPP group and non-MPP groups were compared.

RESULTS

The proportion of CAP children among hospitalized children was 32.4%, 38.5%, and 39.5% in 2017, 2018, and 2019, respectively, showing an upward trend (P<0.05).The prevalence rate of MPP was highest in the third quarter (30.2%) and the fourth quarter (39.2%) and lowest in the second quarter (13.2%) (χ²=51.8, P<0.05). Compared with the non-MPP group, the MPP group had significantly higher incidence of severe pneumonia (19.4% vs. 12.0%, χ²=20.99), incidence of complications (16.1% vs. 6.5%, χ²=48.24), proportion of patients undergoing flexible bronchoscopy (38.4% vs. 9.0%, χ²=252.79), and hospitalization costs (all P<0.05), along with significantly longer hospital stay (6 vs. 4 days, z=-11.131). A dynamic comparison of the clinical characteristics of MPP in 3 years showed that the number of children with MPP increased significantly in preschoolers in 2018 (37.3%) and in school-aged or older children in 2019 (53%) (P<0.05). MPP peaks occurred in August 2018 and November 2019. The total hospitalization costs, examination fees, and non-medication treatment costs increased significantly (the z values were 35.24, 46.79, and 9.64, respectively; P<0.05) year by year among MPP children; there was no significant difference in the medication cost over these 3 years (z=4.81, P>0.05).

CONCLUSIONS

The proportions of severe pneumonia, complications, and use of flexible bronchoscopy as well as the hospitalization days and costs are higher in MPP children. General hospitals should develop integrated clinical quality control programs for MPP children, so as to optimize the allocation of medical resources.

The clinical significance of IL-6 s and IL-27 s in Bronchoalveolar lavage fluids from children with mycoplasma pneumoniae pneumonia

Background

IL-6 was associated with the severity of mycoplasma pneumoniae pneumonia (MPP). But the relationship between IL-27 and MPP was unknown.

Methods

Ninety-eight patients with MPP < 14 years old were enrolled in this study and divided into groups by severity (mild cases and severe cases), infection types (MP single infection group and MP mixed infection group) and DNA loads (low MP DNA loads group and high MP DNA loads group), respectively. Fifteen children with foreign bodies in bronchus were also enrolled as control. IL-6 s and IL-27 s in bronchoalveolar lavage fluids (BALFs) from these children were measured by ELISA.

Results

There were significant differences in IL-6 s of BALFs from patients between mild cases and severe cases, MP single infection group and MP mixed infection group, and low MP DNA loads group and high MP DNA loads group, respectively (P < 0.05). Compared with IL-6 s of BALFs from control, IL-6 s in BALFs from the 6 patient groups were significantly higher (P < 0.05). IL-27 s in BALFs from MP mixed infection group were significantly lower than those from MP single infection group and control (P < 0.05) respectively.

Conclusion

IL-6 was firmly associated with MPP and had potential application in clinical practice while IL-27 was not related to MP infection.

Epidemiological and clinical analysis of community-acquired Mycoplasma pneumonia in children from a Spanish population, 2010-2015

Introduction and objectives

Mycoplasma pneumoniae (MP) is one of the most common etiological agents of community-acquired pneumonia (CAP) in children. We aimed to describe the clinical and epidemiological characteristics, treatment and outcome of children diagnosed with community-acquired MP pneumonia (CAMP) in a tertiary hospital in Valencia, Spain.

Material and methods

Medical records of children <14 years with CAMP were retrospectively reviewed from January 2010 to December 2015. Patients with radiological evidence of pneumonia and microbiological confirmation of MP (PCR from nasopharyngeal swab and/or serum specific IgM) were considered CAMP.

Results

One hundred and sixty two children were diagnosed with CAMP; median age 6 years (IQR: 4-9). The positive MP test rate among children with CAP progressively increased with age as did the empirical use of macrolides. There were two peaks of cases in 2011 and in 2015, being July, August, November and December the seasons with the higher number of cases. The most frequent radiological pattern was segmental infiltrate (62.3%) and 22 (13.6%) children had pleural effusion. It was noteworthy the mild symptomatology and low levels of inflammatory parameters that children with CAMP had. A macrolide was empirically initiated in 68.5% of cases. Hospital admission rate was inversely proportional to patient's age.

Conclusions

According to this study, older, less symptomatic patients and with lower inflammatory parameters had the greatest rate of MP infection among children with CAP and thus they could benefit of empiric macrolide therapy. Therefore, knowing the epidemiology of a geographical area may be important for the management of CAP in children.

Mycoplasma pneumoniae-related hepatitis in children

Mycoplasma pneumoniae (M. pneumoniae) is a small bacterium characterized by the absence of cell wall. It is a human pathogen causing upper and lower respiratory infections, both in adults and children. However, it is also considered to be implicated in the pathogenesis of several types of extra-respiratory diseases, including some gastrointestinal disorders. The liver involvement in children during or after M. pneumoniae infections is analyzed and discussed in this review. Through a systematic literature search, it is evidenced that M. pneumoniae is not infrequently associated with alteration of liver function, but rarely causes acute and severe hepatitis in children. M. pneumoniae should be considered as an unusual cause of acute hepatitis in children, whenever the most common hepatotropic viruses have been excluded. The pathogenesis of M. pneumoniae-related hepatitis is likely to be immune-mediated: both the innate and adaptive immune responses may play a fundamental role. However, the exact pathological mechanisms have to be elucidated yet. Further clinical studies are needed in order to understand the actual relevance of this microorganism in liver disease and its pathogenesis.

Immunoglobulin M profile of viral and atypical pathogens among children with community acquired lower respiratory tract infections in Luzhou, China

Background

Community-acquired lower respiratory tract infections (CA-LRTIs) are the primary cause of hospitalization among children globally. A better understanding of the role of atypical pathogen infections in native conditions is essential to improve clinical management and preventive measures. The main objective of this study was to detect the presence of 7 respiratory viruses and 2 atypical pathogens among hospitalized infants and children with community-acquired lower respiratory tract infections in Luzhou via an IgM test.

Methods

Overall, 6623 cases of local hospitalized children with 9 pathogen-IgM results from 1st July 2013 to 31st Dec 2016 were included; multidimensional analysis was performed.

Results

1) Out of 19,467 hospitalized children with lower respiratory tract infections, 6623 samples were collected, for a submission ratio of 33.96% (6623 /19467). Of the total 6623 serum samples tested, 5784 IgM stains were positive, for a ratio of 87.33% (5784 /6623). Mycoplasma pneumoniae (MP) was the dominant pathogen (2548 /6623, 38.47%), with influenza B (INFB) (1606 /6623, 24.25%), Legionella pneumophila serogroup 1 (LP1) (485 /6623, 7.32%) and parainfluenza 1, 2 and 3(PIVs) (416 /6623, 6.28%) ranking second, third and fourth, respectively.

2) The distribution of various pathogen-IgM by age group was significantly different (χ² = 455.039, P < 0.05).

3) Some pathogens were found to be associated with a certain age of children and seasons statistically.

Conclusions

The dominant positive IgM in the area was MP, followed by INFB, either of which prefers to infect children between 2 years and 5 years in autumn. The presence of atypical pathogens should not be underestimated clinically as they were common infections in the respiratory tract of children in the hospital.

The Clinical Presentation of Pediatric Mycoplasma pneumoniae Infections-A Single Center Cohort

BACKGROUND

Mycoplasma pneumoniae (MP) is a major cause of community-acquired upper and lower respiratory infections in school-age children; however, there is increasing recognition that younger children are also affected. Clinical manifestations vary from asymptomatic, to severe complicated pneumonia sometimes with extrapulmonary manifestations.

METHODS

We reviewed the medical records of all MP positive pediatric patients admitted to the Hadassah-Hebrew University Medical Center. MP positive case was defined if MP polymerase chain reaction was positive from an oropharyngeal swab sent from 2007 to 2017.

RESULTS

During the study period, we identified 353 MP positive pediatric cases, of which 51.3% (181 of 353) were younger than 6 years old. Full clinical data were available for 332 of 353 (94%). The median age was 5.7 years (range, 3 weeks to 18 years). Disease presentation differed between younger and older children. Children older than 6 years were more likely to have chest radiograph confirmed pneumonia (66% vs. 52%; P = 0.009), while younger children were more likely to have other respiratory manifestations (37% vs. 25%; P = 0.017). The duration of hospitalization and pediatric intensive care unit admission rate, however, did not differ between age groups. The rate of extrapulmonary manifestations were also similar.

CONCLUSIONS

MP-associated infection is a significant cause of hospitalization in the pediatric population including younger children (<6 years old). However, the clinical presentation in younger age is less typical than is thought. These findings should prompt clinicians to consider MP infections also in children younger than 6 admitted with fever even without pneumonia.

Clinical characteristics of the lower respiratory tract infection caused by a single infection or coinfection of the human parainfluenza virus in children

BACKGROUND

Human parainfluenza virus (HPIV), usually combined with other pathogens, causes lower respiratory tract infection (LRTI) in children. However, clinical characteristics of HPIV coinfection with other pathogens were unclear. This study aimed to investigate the viral and atypical bacterial etiology of LRTI in children and compare the clinical characteristics of HPIV single infection with those of coinfection.

METHODS

This study included 1335 patients, aged between 1 to 71 months, diagnosed with LRTI in Yuying Children's Hospital, Zhejiang, China, from December 2013 to June 2015. Nasopharyngeal secretions were collected, and respiratory pathogens were detected using Multiplex polymerase chain reaction. The clinical data of patients were collected and analyzed.

RESULTS

At least 1 pathogen was detected in 1181/1335 (88.5%) patients. The pathogens identified most frequently were respiratory syncytial virus, human rhinovirus, HPIV, adenovirus, and human metapneumovirus. The coinfection rate was 24.8%. HPIV coinfection with other viruses was more associated with running nose, shortness of breath, and oxygen support compared with HPIV single infection. Moreover, HPIV coinfection with atypical bacteria was more related to running nose, moist rales, and longer hospital duration compared with HPIV single infection, and also to longer hospital duration compared with coinfection with other viruses.

CONCLUSIONS

This study demonstrated that viral infections were highly associated with LRTI and the rate of coinfection was high. HPIV single infection was milder than coinfection with other viruses. Moreover, HPIV coinfection with atypical bacteria was more serious than HPIV single infection and coinfection with other viruses.

Mortality Predictive Scores for Community-Acquired Pneumonia in Children

PURPOSE OF REVIEW

The use of severity score for the staging of pneumonias has emerged as a necessity for the physician caring for this disease. Although there are several established prognostic scoring systems for community-acquired pneumonia in adults, the availability for children are scarce.

RECENT FINDINGS

Recently, scoring system for risk stratification of children with pneumonia were developed in low- and middle-income countries. They use clinical variables that represent known risk factors for severe outcomes of respiratory illness in children, such as hypoxemia, chest indrawing, refusal to feed, malnutrition, age, and stage of HIV disease among others factors. Although they showed good discriminating power and are very useful in low-resource settings, the characteristics of the patients, the local epidemiology of concurrent diseases, the social conditions, and the facilities of the hospitals make them not applicable to developed countries. A new prognostic scale for estimating mortality based on the modified PIRO scale used in adults with pneumonia can be useful for developed countries. Although several scoring systems for the estimation of mortality in childhood CAP were developed in the last years, most of them come from developing countries and the results are not applicable to patients with pneumonia in developed countries. Prospective studies applying scores adapted to the reality of the developed countries are needed.

[Epidemiological and clinical analysis of community-acquired Mycoplasma pneumonia in children from a Spanish population, 2010-2015]

Introducción y objetivos

Mycoplasma pneumoniae (MP) es uno de los agentes etiológicos más comunes de las neumonías adquiridas en la comunidad (NAC) en niños. Objetivo: describir las características clínicas y epidemiológicas, tratamiento y evolución de los pacientes con NAC por MP (NACM) en un hospital terciario de Valencia, España.

Material y métodos

Se revisaron retrospectivamente las historias clínicas de los niños < 14 años con NACM entre enero de 2010 y diciembre de 2015. Los pacientes con evidencia radiológica de neumonía y confirmación microbiológica de MP (PCR de exudado nasofaríngeo y/o anticuerpos IgM específicos frente a MP) se consideraron NACM.

Resultados

Un total de 162 pacientes se diagnosticaron de NACM; mediana de edad de 6 años (rango intercuartílico: 4-9 años). La proporción de pruebas positivas para MP en pacientes con NAC, así como el uso empírico de macrólidos, aumentó progresivamente con la edad. Hubo un pico de casos en 2011 y en 2015, con un máximo de casos en julio, agosto, noviembre y diciembre. El patrón radiológico más frecuente fue el infiltrado segmentario (62,3%), mientras que 22 (13,6%) presentaron derrame pleural. Los niños con NACM desarrollaron una clínica leve, con poca elevación de parámetros inflamatorios. Se inició tratamiento empírico con un macrólido en el 68,5% de los casos. La necesidad de ingreso hospitalario fue inversamente proporcional a la edad del paciente.

Conclusiones

Según este estudio, los niños con NAC de mayor edad tuvieron la mayor proporción de infección por MP, siendo poco sintomáticos y con escasa elevación de parámetros inflamatorios, pudiéndose beneficiar del tratamiento empírico con macrólidos. Por consiguiente, conocer la epidemiología de un área geográfica podría ser importante para el abordaje de las NAC en niños.

The Mycoplasma pneumoniae HapE alters the cytokine profile and growth of human bronchial epithelial cells

Mycoplasma pneumoniae is one of the most common pathogenic causes of community-acquired pneumonia. Hydrogen sulfide, alanine, and pyruvate producing enzyme (HapE) is a recently discovered M. pneumoniae virulence factor that can produce H₂S to promote erythrocyte lysis. However, other cytotoxic effects of HapE have not been explored. The present study examined the effects of this enzyme on normal human bronchial epithelial (NHBE) cells, in an attempt to identify additional mechanisms of M. pneumoniae pathogenesis. Recombinant HapE was purified for use in downstream assays. MTT and colony formation assays were conducted to determine the effects of HapE on cell viability and growth, while flow cytometry was used to examine changes in cell proliferation and cell cycle function. ELISA was performed to examine changes in the cytokine profile of HapE-treated cells. HapE treatment arrested NHBE cells in S phase and inhibited cell proliferation in a concentration-dependent manner. The anti-inflammatory factors interleukin (IL)-4 and IL-6 were significantly enhanced following HapE treatment. Increased secretion of pro-inflammatory factors was not observed. The effects of HapE on the respiratory epithelium may have an impact on the efficiency of host immune surveillance and pathogen elimination, and contribute to the pathogenesis of M. pneumoniae.