Detection of Mycoplasma pneumoniae in different respiratory specimens

Evaluating the role of interleukin-2 and interleukin-12 in pediatric patients with concurrent Mycoplasma pneumoniae and Epstein-Barr virus infections

BACKGROUND

Mycoplasma pneumoniae (MP) frequently causes respiratory infections in children, whereas Epstein-Barr virus (EBV) typically presents subclinical manifestations in immunocompetent pediatric populations. The incidence of MP and EBV co-infections is often overlooked clinically, with the contributory role of EBV in pulmonary infections alongside MP remaining unclear.

AIM

To evaluate the serum concentrations of interleukin-2 (IL-2) and interleukin-12 (IL-12) in pediatric patients with MP pneumonia co-infected with EBV and assess their prognostic implications.

METHODS

We retrospectively analyzed clinical data from patients diagnosed with MP and EBV co-infection, isolated MP infection, and a control group of healthy children, spanning from January 1, 2018 to December 31, 2021. Serum IL-2 and IL-12 levels were quantified using enzyme-linked immunosorbent assay. Logistic regression was employed to identify factors influencing poor prognosis, while receiver operating characteristic (ROC) curves evaluated the prognostic utility of serum IL-2 and IL-12 levels in co-infected patients.

RESULTS

The co-infection group exhibited elevated serum IL-2 and C-reactive protein (CRP) levels compared to both the MP-only and control groups, with a reverse trend observed for IL-12 (P < 0.05). In the poor prognosis cohort, elevated CRP and IL-2 levels, alongside prolonged fever duration, contrasted with reduced IL-12 levels (P < 0.05). Logistic regression identified elevated IL-2 as an independent risk factor and high IL-12 as a protective factor for adverse outcomes (P < 0.05). ROC analysis indicated that the area under the curves for IL-2, IL-12, and their combination in predicting poor prognosis were 0.815, 0.895, and 0.915, respectively.

CONCLUSION

Elevated serum IL-2 and diminished IL-12 levels in pediatric patients with MP and EBV co-infection correlate with poorer prognosis, with combined IL-2 and IL-12 levels offering enhanced predictive accuracy.

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

Background

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

Methods

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

Results

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

Conclusions

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

Comparative study of diagnostic efficacy of sputum and bronchoalveolar lavage fluid specimens in community-acquired pneumonia children treated with fiberoptic bronchoscopy

BACKGROUND

Community-acquired pneumonia (CAP) is usually diagnosed in children, and the type of respiratory specimen is critical. Differences in pathogens detection between induced sputum (IS) and bronchoalveolar lavage fluid (BALF) have not been evaluated.

METHODS

In 2018, paired sputum and BALF samples from CAP hospitalised children with indications for bronchoalveolar lavage (BAL) were subjected to multiplex PCR for the detection of 11 common respiratory pathogens.

RESULTS

A total of 142 children with paired sputum and BALF were tested. The overall positivity rate was 85.9% (122/142) for sputum and 80.3% (114/142) for BALF. The two specimens presented almost perfect agreement between the detection on M. pneumoniae, influenza A, influenza B, bocavirus and RSV. In contrast, adenovirus had the lowest kappa value of 0.156, and a false negative rate (FNR) of 66.7%. Rhinovirus had the highest false positive rate (FPR) as 18.5%. The consistent rate was significantly higher in school-age children than those under 1 year old (p = .005). Bacterial co-infection in BALF specimens were observed in 14.8% (21/142). Of the 11 discordant pairs of specimens, 9 cases were sputum(+)/BALF(-) with adenovirus predominating.

CONCLUSION

Our findings suggest that the consistency of results between sputum and BALF is pathogen specific. Careful consideration needs to be given to whether sputum can be used as a substitute for BALF when children are young or co-infections with bacteria are suspected.

Effects of bronchoalveolar lavage on Mycoplasma Pneumoniae pneumonia: A propensity score matched-cohort study

BACKGROUND

The purpose of this study was to evaluate the efficacy and safety of BAL in treating MPP.

METHODS

From January 2013 to January 2019, 1,689 pediatric patients with MPP were analyzed retrospectively. Patients were subdivided into BAL group and non-BAL group according to whether they received BAL treatment within seven days after admission. The propensity score matching method matched patients' baseline characteristics (1:1). The primary outcomes were hospital stays and the cure rate. Secondary outcomes included mortality, co-infection, repeat hospitalization within 30 days, and total cost of treatment.

RESULTS

After matching, 524 patients (BAL: 262; control: 262) were recorded. The BAL group had significantly shorter hospital stays (OR: 0.5, 95% CI: 0.4-0.7). Meanwhile, BAL did not significantly modify the cost, co-infection rate, and mortality. In subgroup analyses, the group with BAL intervention within three days had a significantly shorter hospital stay (OR: 0.4, 95% CI: 0.3-0.5) compared with the group with BAL intervention three days after admission.

CONCLUSIONS

Early BAL intervention is a better treatment than conventional drug therapy alone, and no significant complications were seen in this study. BAL intervention has an excellent clinical benefit. The earlier the intervention, the better the effect.

Severe Pediatric Mycoplasma pneumoniae Infection Requiring Veno-venous Extracorporeal Membrane Oxygenation

Mycoplasma pneumoniae (MP) is an atypical bacterial pathogen that typically causes mild respiratory symptoms. Rarely, MP is associated with acute respiratory distress syndrome, a condition marked by widespread inflammation in the lungs that often requires invasive support. We report a case of severe acute respiratory distress syndrome requiring veno-venous extracorporeal membrane oxygenation in an otherwise healthy adolescent because of MP.

Mycoplasma pneumoniae: a pathogen with unsolved therapeutic problems

INTRODUCTION

Despite the amount of new information, the most effective approach for the diagnosis and treatment of Mycoplasma pneumoniae infections is not established. In this narrative review the pharmacological options for macrolide-resistant (ML) M. pneumoniae infections in children are discussed.

AREAS COVERED

Despite significant improvement in the diagnosis and in the definition of diseases potentially associated with this pathogen, not all the problems related to M. pneumoniae infection are solved. True epidemiology of M. pneumoniae diseases and the real role of this pathogen in extra-respiratory manifestations is still unestablished. This reflects on therapy. It is not known whether antibiotics are really needed in all the cases, independently of severity and localization. The choice of antibiotic therapy is debated as it is not known whether ML resistance has clinical relevance. Moreover, not precisely defined is the clinical importance of corticosteroids for improvement of severe cases, including those associated with ML-resistant strains.

EXPERT OPINION

Improvement in M. pneumoniae identification is mandatory to reduce antibiotics overuse , especially in the presence of ML-resistant strains. Priority for future studies includes the evaluation of the true benefit of therapeutic approaches including corticosteroids in patients with severe CAP and in those with extra-respiratory M. pneumoniae diseases.

Bronchial casts associated with Mycoplasma pneumoniae pneumonia in children

Objective

This study was performed to analyze 22 cases of Mycoplasma pneumoniae pneumonia (MPP) associated with bronchial casts (BCs) in children.

Methods

We retrospectively reviewed all cases of MPP in children treated at our institution from November 2015 to December 2016. Demographic information, laboratory parameters, radiologic and fiberoptic bronchoscopy findings, treatment outcomes, and follow-up results were analyzed.

Results

Among 161 patients with MPP, 22 had BCs and 139 had no BCs. All BCs occurred in a segmental or subsegmental bronchus and were removed by fiberoptic bronchoscopy. Patients with BCs had a longer duration of fever after admission and higher incidence of refractory MPP. Substantially more children with than without BCs had a high M. pneumoniae load in the bronchoalveolar lavage fluid. All patients with BCs but only 55.4% without BCs were given methylprednisolone in addition to the standard antibiotic treatment. A significantly higher proportion of children with than without BCs received oxygen therapy. After discharge, complete radiological resolution took significantly longer in children with than without BCs.

Conclusions

In children with MPP, prompt removal of BCs may be necessary to prevent BC propagation. MPP with BCs is more severe than that without BCs, and treatment and recovery are more difficult.

Acute saddle pulmonary embolism: A rare complication of mycoplasma pneumonia

Background/Introduction

Mycoplasma pneumonia affects 1% of the population in the United States. The majority of patients infected with Mycoplasma experience upper respiratory tract infection symptoms, and about 10% of patients infected with Mycoplasma develop pneumonia. A rare complication is a pulmonary embolism (PE), which may be life-threatening if not diagnosed early and treated promptly. Our case explores the presentation of Mycoplasma pneumonia complicated by acute saddle PE, an association only reported in the form of case reports globally.

Case presentation

A 75-year-old previously healthy female presented to the emergency department with shortness of breath. The patient was found to be in acute hypoxic respiratory failure secondary to community acquired pneumonia and antibiotics were started. During hospitalization, her respiratory failure worsened and had to be escalated to a non-rebreather mask. Repeat chest X-ray showed a possible developing infiltrate on the left side. Antibiotic coverage was escalated and broadened. Serology was positive for mycoplasma pneumoniae. Telemetry monitoring showed non-sustained episodes of Atrial Fibrillation and Electrocardiogram showed the presence of new-onset SIQIIITIII. Computer Tomography Angiography of the chest showed acute saddle PE. The patient was subsequently upgraded to the ICU, where she was intubated and started on catheter-directed thrombolysis to decrease clot burden.

Conclusion

To our knowledge, this is the first case of acute saddle PE in a live patient with mycoplasma pneumonia. This entity is important in order to ensure early diagnosis of PE in association with mycoplasma pneumonia and the initiation of early treatment to improve patient outcomes.

Clinical characteristics of Kawasaki disease complicated with Mycoplasma pneumoniae pneumonia: A retrospective study

This study aimed to investigate the inner linkage and mechanism of Mycoplasma pneumoniae (MP) infection and Kawasaki disease (KD), as well as the risk factors of outcome in this cohort of patients.A retrospective study was performed in 210 patients diagnosed with KD complicated with community acquired pneumonia (CAP) in Children's Hospital, Zhejiang University School of Medicine from January 2014 to December 2017. They were divided into two groups based on MP infection: MP infection group (n = 97) and non-MP infection group (n = 113). We compared the variables of these two groups based on medical records.The MP infection group had higher ESR than the non-MP infection group. During hospitalization, the non-MP infection group had higher levels of WBC during hospital, LDH, PCT, and lower HB when compared to the MP infection group. No differences were found in the hs-CRP level, N%, PLT, ALT, CKMB, and cytokine levels (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ) between MP and non-MP infection group. Likewise, no difference was found in fever duration or hospital stays between them. Totally 19 patients in the infection group had CAA with a rate of 19.59%; and 27 (23.89%) patients had CAA in the non-MP infection group. Unfortunately, no difference was found in CAA rate between the two groups.MP infection may occur simultaneously in children with Kawasaki disease. KD patients with MP infection tended to occur in older population. MP infection may not increase the risk of CAA, which still needs further large-scaled studies to confirm. Clinicians should be alert to KD patients with high level of ESR. MP should be screened and early treatment with macrolides should be given timely.

Impact of Epstein-Barr virus coinfection in Mycoplasma pneumoniae pneumonia

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

Mycoplasma pneumoniae detection in children with respiratory tract infections and influence on management - a retrospective cohort study in Switzerland

AIM

To evaluate the frequency of Mycoplasma pneumoniae in nasopharyngeal specimens from children with respiratory tract infections (RTIs) and to detail clinical characteristics and management.

METHODS

The study was designed as a retrospective cohort study. All children with RTI and nucleic acid amplification testing from nasopharyngeal specimens were analysed. Clinical data were extracted from electronic health records for all M. pneumoniae-positive cases. Stored samples of cases and a random selection of matched controls were retested using a M. pneumoniae-specific nucleic acid amplification test.

RESULTS

Of 4460 children, 70 (1.6%) were positive for M. pneumoniae with a median age of 6.4 (IQR: 2.7-9.7). M. pneumoniae was the only organism identified in 50/64 (78%) cases. Macrolide treatment was prescribed in 52/65 (80%); prescription was empirical in 29/52 (56%) and targeted in 23/52 (44%) with no difference regarding patient age, oxygen requirement or duration of hospitalisation.

CONCLUSION

The prevalence of M. pneumoniae in nasopharyngeal specimens of children with RTI was low. The detection of M. pneumoniae influenced antibiotic prescriptions, but the benefit of early empirical versus targeted treatment remains unclear.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

High co-expression of TNF-α and CARDS toxin is a good predictor for refractory Mycoplasma pneumoniae pneumonia

Background

Early distinction between refractory M. pneumoniae pneumonia (RMPP) and non-RMPP (NRMPP) is still difficult. The community-acquired respiratory distress syndrome (CARDS) toxin can induce inflammatory and histopathological phenotypes associated with M. pneumoniae infection. This study aimed to investigate the clinical significance of CARDS toxin and pro-inflammatory cytokines in children with RMPP and to explore whether CARDS toxin can induce TNF-α expression.

Methods

Levels of CARDS toxin and cytokines in BALF from control and children with MPP were determined by real-time PCR and ELISA, respectively. A receiver-operating characteristic (ROC) analysis was performed to assess the diagnostic values of CARDS toxin, TNF-α, and IL-6 in RMPP. The recombinant CARDS toxin was constructed and prepared at different concentrations for stimulation of RAW264.7 cells. After co-culture with CARDS toxin, cytokines were detected by ELISA and the mRNA levels were measured by real-time PCR. Effects of CARDS toxin and TNF-α on inflammatory cell infiltration and mucus secretion in mouse lungs were also evaluated.

Results

Levels of CARDS toxin, TNF-α and IL-6 in bronchoalveolar lavage fluid (BALF) were significantly higher in RMPP cases compared with NRMPP cases. Furthermore, TNF-α had better diagnostic ability for differentiation of RMPP with AUC of 0.824 and Youden index of 0.692 compared with CARDS toxin and IL-6. Moreover, CARDS toxin was positively correlated with TNF-α level in MPP cases. In vitro assay revealed that CARDS toxin induced RAW264.7 macrophages to secrete TNF-α. Further in vivo assay showed that TNF-α deletion partially abrogated the CARDS toxin-mediated induction of inflammatory cell infiltration and mucus secretion in mouse lungs.

Conclusions

The high co-expression of TNF-α and CARDS toxin in BALF is a good diagnostic biomarker for differentiating children with RMPP and NRMPP.

Rapid Detection of the Macrolide Sensitivity of Pneumonia-Causing Mycoplasma pneumoniae Using Quenching Probe Polymerase Chain Reaction (GENECUBE®)

BACKGROUND AND OBJECTIVES

Macrolide-resistant Mycoplasma pneumoniae (MR-MP) have been reported worldwide. Strategies for the treatment of MR-MP are a key focus of research. The GENECUBE^® is a novel, fully automated rapid genetic analyzer. The goals of this study were to assess the macrolide sensitivity of M. pneumoniae (MP) isolates by analyzing 23S ribosomal RNA (rRNA) gene sequences using a GENECUBE^®-based system and to determine the validity of this system in determining clinical treatment options for MP pneumonia.

METHODS

This was an observational retrospective study including 150 children with MP pneumonia. We used quenching probe polymerase chain reaction (Q-probe PCR) as implemented in the GENECUBE^® system to detect macrolide resistance-causing mutations in the MP 23S rRNA gene. We compared the duration of fever between patients receiving initial empirical antibiotic treatment (Empirical T group) and those receiving treatment after Q-probe PCR (PCR First group) diagnosis.

RESULTS

Selecting antibiotic treatment after Q-probe PCR significantly shortened the duration of fever compared to empirical antibiotic treatment (PCR First group, median: 6.0 days [n = 32]; Empirical T group, median: 7.5 days [n = 66]; p = 0.002). Comparison of macrolide sensitivity using Q-probe PCR and clinical diagnosis showed that the reliability of Q-probe PCR was nearly validated for macrolide sensitivity.

CONCLUSION

Q-probe PCR as implemented by GENECUBE^® is a useful tool for the diagnosis of MP pneumonia and enables optimization of the selection of antibiotics in order to rapidly improve the clinical course of disease.

Comparison of enzyme-linked immunosorbent assay with indirect immunofluorescence assay for the diagnosis of Mycoplasma pneumoniae infection

BACKGROUND

The study aimed to compare enzyme-linked immunosorbent assay (ELISA) with indirect immunofluorescence assay (IFA) in the diagnosis of Mycoplasma pneumoniae infection.

METHODS

From March 2016 to May 2017, 180 patients suspected with M. pneumoniae infection were enrolled. The SeroMP kit using ELISA and PNEUMOSLIDE kit using IFA were performed in parallel to detect the IgM antibodies against M. pneumoniae. Cohen's kappa statistics were used to assess the agreement between the ELISA and IFA assays, multivariate logistic regression analysis was used to evaluate risk factors for the discordance between the ELISA and IFA assays.

RESULTS

The mean age of the enrolled subjects was 46.6 ± 21.1 years. For detection of M. pneumoniae infection, the positivities of the ELISA and IFA assays were 15.6% (95% CI: 11.0%, 21.6%) and 10.0% (95% CI: 6.4%, 15.3%), respectively. The total positivity was 19.4% (95% CI: 14.3%, 25.8%). The agreement between the ELISA and IFA assays was low (κ = 0.117, P < 0.001). Variables associated with discordant results between ELISA and IFA assays in multivariate analysis were as follows: male (OR: 0.366; 95% CI: 0.149, 0.899; P < 0.05), age (>33 years old; OR: 0.313; 95% CI: 0.129, 0.758; P < 0.05).

CONCLUSION

In detection of M. pneumoniae infection, low agreement was found in IgM assays between the ELISA and IFA methods, female and younger age were significant risk factors for the discordance. A combination of ELISA and IFA tests would be recommended, in order to detect more patients suspected of M. pneumoniae infection in clinical practice.

Comparison of the molecular characteristics of Mycoplasma pneumoniae from children across different regions of China

Previous molecular characterization of Mycoplasma pneumoniae in China focused only on one or two cities. In this study, we characterized 835 samples from patients suspected to be infected with M. pneumoniae; these samples were collected in 2016 from pediatric patients from different regions of China. Multiple locus variable number tandem repeat analysis (MLVA), P1-restriction fragment length polymorphism (RFLP) analysis, and sequencing of the domain V of 23S rRNA were performed to compare genotype distribution across different locations. Two-hundred-and-thirteen samples tested positive for M. pneumoniae by PCR. P1 types were identified in 154 samples: 78.6% were type I and 21.4% were type II. Type I was the most prevalent genotype in five locations, except Nanjing where type II was the most common type (p < 0.01). Five distinct MLVA types were identified in the 172 samples. Genotype M4-5-7-2 was predominant at all locations, except Nanjing where type 3-5-6-2 was the most common (p < 0.01). Macrolide resistance-associated mutations were identified in 186 (76.3%) samples. The resistance rate differed with the location. This study showed that genotypes and macrolide resistance rate differed across China. The most prevalent genotype in China remains M4-5-7-2/P1-1. The resistance rate decreased, along with changes to the M4-5-7-2 genotype.

The role of granulocyte macrophage colony stimulating factor in hospitalized children with Mycoplasma pneumoniae pneumonia

BACKGROUND

Inappropriate inflammatory response in children with M. pneumoniae infection might be associated with disease severity. The role of Granulocyte macrophage colony stimulating factor (GM-CSF) in hospitalized children with Mycoplasma pneumoniae pneumonia (MPP) has not been fully discussed.

METHODS

Clinical and laboratory data of a total 40 children with MPP were collected. GM-CSF and myeloperoxidase (MPO) were detected by ELISAs. Meanwhile, normal human bronchial epithelium was infected by M. pneumoniae and neutrophils were stimulated by GM-CSF to explore GM-CSF and MPO release in supernatant, respectively.

RESULTS

Compared to control group, a significant increased percentage of neutrophils and decreased percentage of macrophages in bronchoalveolar lavage fluid of children with MPP was observed (P < 0.05). Children with MPP had significantly higher levels of GM-CSF (P = 0.0047) and MPO (P = 0.0002) in BALF compared to the controls. Level of GM-CSF in BALF was associated with duration of fever (r = 0.42, P = 0.007) and strongly correlated with level of MPO (r = 0.075, P = 0.0005). Levels of GM-CSF and MPO significantly decreased (both P < 0.05) after treatment. In vitro, M. pneumoniae induced GM-CSF expression in a time-dependent manner during a 72-h period (P < 0.05) and MPO secretion significantly increased by recombinant human GM-CSF stimulation at 24h (P < 0.05).

CONCLUSION

GM-CSF could be induced by M. pneumoniae infection in vivo and vitro. Childen with high level GM-CSF had longer duration of fever. GM-CSF probably plays a vital role in neutrophil inflammation in M. pneumoniae infection.

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

Objective

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

Methods

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

Results

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

Conclusion

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

[Description and role of bacteriological techniques in the management of lung infections]

Les pneumopathies aiguës recouvrent des contextes cliniques variés et les étiologies bactériennes impliquées le sont tout autant. Aucun outil microbiologique n’est 100 % sensible ni 100 % spécifique et malgré les investigations, plus de 30 % des pneumopathies restent sans étiologie identifiée. Si aucun prélèvement n’est indiqué pour les patients traités en ambulatoire, les prélèvements respiratoires non invasifs sont à privilégier pour les pneumopathies aiguës hospitalisées (communautaires ou associées aux soins), tandis que les prélèvements invasifs sont indiqués en seconde ligne pour les pneumopathies aiguës communautaires en réanimation, et en première ligne pour les pneumopathies aiguës de l’immunodéprimé. La culture microbiologique garde une place importante, à condition que le malade soit prélevé avant instauration de l’antibiothérapie. Certains contextes peuvent justifier le recours aux hémocultures, à la recherche d’antigènes urinaires ou aux sérologies. Les PCR rendent déjà service au quotidien mais l’avenir à court terme appartient probablement aux panels moléculaires multiplex capables de détecter de nombreux micro-organismes en quelques heures, surtout dans les pneumopathies communautaires sévères de réanimation et les pneumopathies aiguës de l’immunodéprimé. Le séquençage nucléotidique haut débit révolutionnera bientôt le diagnostic microbiologique, en pneumologie comme dans les autres domaines de l’infectiologie.

Mycoplasma pneumoniae from the Respiratory Tract and Beyond

Mycoplasma pneumoniae is an important cause of respiratory tract infections in children as well as adults that can range in severity from mild to life-threatening. Over the past several years there has been much new information published concerning infections caused by this organism. New molecular-based tests for M. pneumoniae detection are now commercially available in the United States, and advances in molecular typing systems have enhanced understanding of the epidemiology of infections. More strains have had their entire genome sequences published, providing additional insights into pathogenic mechanisms. Clinically significant acquired macrolide resistance has emerged worldwide and is now complicating treatment. In vitro susceptibility testing methods have been standardized, and several new drugs that may be effective against this organism are undergoing development. This review focuses on the many new developments that have occurred over the past several years that enhance our understanding of this microbe, which is among the smallest bacterial pathogens but one of great clinical importance.

[Application of Mycoplasma pneumoniae antibody and load index in the diagnosis of Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.

METHODS

A total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.

RESULTS

The cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).

CONCLUSIONS

MPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.

Increased concentrations of soluble B7-H3 and interleukin 36 in bronchoalveolar lavage fluid of Children with Mycoplasma pneumoniae pneumonia

Background

The purpose of this study is to explore the correlations of interleukin 36 (IL-36) and Soluble B7-H3 (sB7-H3) levels in bronchoalveolar lavage fluid (BALF) with clinical characteristics and laboratory findings.

Methods

A total of 35 children with M. pneumnoiae pneumonia (MPP) and 15 control subjects were enrolled. BALF concentrations of sB7-H3 and IL-36 were detected using enzyme-linked immunosorbent assays and clinical profiles of children with MPP were obtained.

Results

Children with MPP had significantly higher levels of sB7-H3 and IL-36 compared to control subjects (both P < 0.05). Meanwhile, children with pleural effusion had significantly higher levels of sB7-H3 and IL-36 compared to children without pleural effusion (both P < 0.05). BALF concentration of sB7-H3 was strongly associated with concentration of IL-36 (r = 0.796, P < 0.0001) and sB7-H3 was correlated with duration of fever (r = 0.427, P = 0.11) and length of stay (r = 0.345, P = 0.043). Both concentrations of sB7-H3 and IL-36 were significantly decreased in convalescent phase after treatment (both P < 0.05).

Conclusion

Both soluble B7-H3 and IL-36 may play an important role in pathogenesis of M. pneumoniae infection and sB7-H3 could be useful as a prognostic predictor or biomarker of MPP.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1555-6) contains supplementary material, which is available to authorized users.

Role of the Mycoplasma pneumoniae/Interleukin-8/Neutrophil Axis in the Pathogenesis of Pneumonia

Neutrophil infiltration is the characteristic pathological feature of M. pneumoniae pneumonia (MPP). This study aimed to explore the associations among neutrophil activity, clinical presentation, and role of the M. pneumoniae/interleukin-8 (IL-8)/neutrophil axis in the pathogenesis of MPP. A total of 42 patients with MPP were prospectively enrolled in the study. Neutrophil activity, including matrix metalloproteinase-9 (MMP-9), myeloperoxidase (MPO), and neutrophil elastase (NE), were measured. Clinical information was collected for all patients and control group. In vitro, IL-8 production was measured at different time points after M. pneumoniae infection of bronchial epithelial cells, and neutrophil activity was analyzed after IL-8 stimulation. The percentage of neutrophil in the bronchoalveolar lavage fluid was higher in the group of patients with high levels of M. pneumoniae DNA than in those with low levels of M. pneumoniae DNA (P < 0.05). IL-8, MMP-9, and NE in patients with MPP significantly increased compared with controls and decreased after treatment (P < 0.05). MPO and MMP-9 were associated with duration of fever (r = 0.332, P < 0.05) and length of stay (r = 0.342, P < 0.05), respectively. In vitro, M. pneumoniae induced IL-8 production by bronchial epithelial cells in a time dependent manner. MPO, MMP-9 and NE production by neutrophils significantly increased compared with medium controls after IL-8 stimulation. In summary, the M. pneumoniae/IL-8/neutrophil axis likely plays a vital role in the pathogenesis of MPP.

Rapid diagnosis of Mycoplasma pneumoniae in children with pneumonia by an immuno-chromatographic antigen assay

Mycoplasma pneumoniae is a particularly important pathogen that causes community acquired pneumonia in children. In this study, a rapid test was developed to diagnose M. pneumoniae by using a colloidal gold-based immuno-chromatographic assay which targets a region of the P1 gene. 302 specimens were analyzed by the colloidal gold assay in parallel with real-time PCR. Interestingly, the colloidal gold assay allowed M. pneumoniae identification, with a detection limit of 1 × 10(3) copies/ml. 76 samples were found to be positive in both real-time PCR and the colloidal gold assay; two specimens positive in real-time PCR were negative in the rapid colloidal gold assay. The specificity and sensitivity of the colloidal gold assay were 100% and 97.4%, respectively. These findings indicate that the newly developed immuno-chromatographic antigen assay is a rapid, sensitive and specific method for identifying M. pneumoniae, with potential clinical application in the early diagnosis of Mycoplasma pneumoniae infection.

Diagnostic features of community-acquired pneumonia in children: what's new?

AIM

To critically summarise the available data on diagnosis of CAP in children, focusing on the newest findings and on the need for new studies.

METHODS

Eighty studies on the diagnosis of paediatric community-acquired pneumonia were scrutinised.

RESULTS

We found no significant associations between the signs or symptoms and aetiology of pneumonia and concluded that chest radiographs remain controversial and real-time polymerase chain reaction appears more sensitive than blood cultures.

CONCLUSION

Antibiotic overuse could make it difficult to differentiate viral and bacterial causes. Molecular methods provide promising tools for diagnosing infection by atypical bacteria, but are expensive and should be used selectively.

Community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) contributes significantly to morbidity and mortality, especially in the elderly. Recent advances aimed at improving outcomes and reducing CAP disease burden are summarized.

RECENT FINDINGS

Emerging data suggests that newer CAP risk stratification indices based on disease severity hold promise in predicting intensive care need. Additional evidence supports a role of procalcitonin and pro-adrenomedullin as biomarkers of disease severity and for guiding antimicrobial therapy. New diagnostic tools have greatly contributed to early diagnosis and better-targeted therapy. There is increasing recognition of the role of coinfections in CAP. In patients with severe disease, therefore, current guidelines advise against monotherapy. Although inclusion of coverage for atypical pathogens in nonsevere CAP has been challenged, evidence suggests that such coverage is beneficial in patients with severe disease. Use of steroids as adjunctive therapy for CAP, however, is associated with complications and prolonged hospitalization. Updated prevention strategies include approval of pneumococcal conjugate vaccine (PCV13) for adults at risk.

SUMMARY

Despite these developments research aimed at further reducing CAP-related morbidity and mortality is required. Increasing global life expectancy is likely to expand the at-risk population; therefore, research directed at CAP prevention in view of changing demography is essential.

Investigation of Mycoplasma pneumoniae infection in pediatric population from 12,025 cases with respiratory infection

Although Mycoplasma pneumoniae (MP) is a major pathogen of primary atypical pneumonia in children, the clinical and laboratory characteristics of MP infection in large pediatric population are less reported. Here, we retrospectively analyzed 12,025 hospitalized children with respiratory infection by using serology and polymerase chain reaction (PCR) methods simultaneously. The results showed that 2433 (20.23%) children had MP infection, which mainly occurred in November to April. The presence of sore throat and pharyngitis was peculiar to MP infection. The positive percentage of MP-DNA was higher than that of MP-IgM in children aged <1 (P < 0.0001) and 1-3 years (P < 0.0001). Moreover, the positive rate of P1 gene, the key adhesion gene for MP infection, was higher in children with MP infection than in those with other pathogens (P < 0.0001). Our work provides the clinical information of children MP infection and highlights the superiority of PCR and potential usage of P1 as a diagnosis target for MP infection.

Epidemiological characteristics and meteorological factors of childhood Mycoplasma pneumoniae pneumonia in Hangzhou

BACKGROUND

Mycoplasma pneumoniae (M. pneumoniae) is an important pathogen of pediatric respiratory infections and the relation of M. pneumoniae pneumonia (MPP) with meteorological factors remains obscure. This study aims to investigate the epidemiological characteristics of childhood MPP and observe if there is a relationship between epidemiological characteristics and meteorological factors in Hangzhou.

METHODS

M. pneumoniae DNA in nasopharyngeal aspirates of hospitalized pneumonia children were detected by polymerase chain reaction from January 1, 2007 to December 31, 2009. The positive rates of MPP (MPP rates) in different years, seasons and ages were compared. The relationship between MPP rates and meteorological data, including mean air temperature (°C), mean relative humidity (%), monthly precipitation (mm) and raining days were analyzed.

RESULTS

In 14 799 pneumonia cases found from 2007 to 2009, the MPP rate was 18.5%. Altogether 1610 boys (16.9%) and 1134 girls (21.4%) suffered from MPP with a significant difference between both genders (χ(2)=45.68, P<0.001). In children younger than 1 year, 1-2 years, 3-6 years, and older than 7 years, the MPP rates were 9.8%, 21.1%, 44.4% and 61.6%, respectively. The MPP rates were significantly higher in older children than in younger ones (trends test χ(2)=46.72, P<0.001). In a descending order, the MPP rates in summer, autumn, spring, and winter were 27.8%, 23.9%, 18.0% and 11.6%, respectively (χ(2)=372.75, P<0.001). The MPP rates in 2007 to 2009 were 12.9%, 19.3% and 23.6%, respectively (trends test χ(2)=13.72, P<0.001). Of the four meteorological factors, only monthly mean air temperature was included in the multiple linear regression model (P<0.001).

CONCLUSIONS

This study showed that the MPP rate was higher in older children than in younger ones. Girls had a higher positive rate of MPP than boys. In Hangzhou, MPP was more prevalent in summer and autumn. Air temperature was the only meteorological factor affecting the prevalence of MPP.