Polymerase chain reaction is superior to serology for the diagnosis of acute Mycoplasma pneumoniae infection and reveals a high rate of persistent infection

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.

Antibiotic Resistance Diagnosis in ESKAPE Pathogens-A Review on Proteomic Perspective

Antibiotic resistance has emerged as an imminent pandemic. Rapid diagnostic assays distinguish bacterial infections from other diseases and aid antimicrobial stewardship, therapy optimization, and epidemiological surveillance. Traditional methods typically have longer turn-around times for definitive results. On the other hand, proteomic studies have progressed constantly and improved both in qualitative and quantitative analysis. With a wide range of data sets made available in the public domain, the ability to interpret the data has considerably reduced the error rates. This review gives an insight on state-of-the-art proteomic techniques in diagnosing antibiotic resistance in ESKAPE pathogens with a future outlook for evading the "imminent pandemic".

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

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

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.

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.

Development of Loop-Mediated Isothermal Amplification Assay Targeting lytA and psaA Genes for Rapid and Visual Diagnosis of Streptococcus pneumoniae Pneumonia in Children

Streptococcus pneumoniae (S. pneumoniae) is a common major human pathogen associated with community-acquired pneumonia, septicemia, meningitis, and otitis media. It is difficult to isolate and identify S. pneumoniae form clinical samples. To evaluate a novel, rapid, sensitive, and specific loop-mediated isothermal amplification (LAMP) assay to detect S. pneumoniae pneumonia in children, we designed specific LAMP primers targeting lytA and psaA genes. We optimized the reaction time and reaction system, and evaluated its sensitivity and specificity of detection using real-time turbidity monitoring and visual observation. We also analyzed the molecular characteristics of the isolates obtained from the positive samples. The primer sets LytA-1 and PsaA-2 amplified the genes in the shortest times, and 63°C was confirmed as the optimum reaction temperature. The detection sensitivity of each reaction was 10 and 100 copies/μL with primer sets LytA-1 and PsaA-2, respectively. This LAMP assay showed no cross-reactivity with other 27 pathogens. To describe the availability of this method, we collected 748 clinical samples from children with pneumonia. Among them, 135 were confirmed to be S. pneumoniae positive by LAMP. The sensitivity was 100% (95% CI 96.4–100%), specificity 99.0% (95% CI 97.8–99.6%). Including them, 50 were co-infected with Mycoplasma pneumoniae. This LAMP assay detected S. pneumoniae in 1 h and the results can be identified with visual naked eyes. Thus, it will be a powerful tool for S. pneumoniae early diagnosis and effective antibiotic therapy.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

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

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

Antigen-Presenting Cells in the Airways: Moderating Asymptomatic Bacterial Carriage

Bacterial respiratory tract infections (RTIs) are a major global health burden, and the role of antigen-presenting cells (APCs) in mounting an immune response to contain and clear invading pathogens is well-described. However, most encounters between a host and a bacterial pathogen do not result in symptomatic infection, but in asymptomatic carriage instead. The fact that a pathogen will cause infection in one individual, but not in another does not appear to be directly related to bacterial density, but rather depend on qualitative differences in the host response. Understanding the interactions between respiratory pathogens and airway APCs that result in asymptomatic carriage, will provide better insight into the factors that can skew this interaction towards infection. This review will discuss the currently available knowledge on airway APCs in the context of asymptomatic bacterial carriage along the entire respiratory tract. Furthermore, in order to interpret past and futures studies into this topic, we propose a standardized nomenclature of the different stages of carriage and infection, based on the pathogen’s position with regard to the epithelium and the amount of inflammation present.

Absence of Association between Previous Mycoplasma pneumoniae Infection and Subsequent Myasthenia Gravis: A Nationwide Population-Based Matched Cohort Study

Mycoplasma pneumoniae (M. pneumoniae) is not only one of the most common pathogenic bacteria for respiratory infection but also a trigger for many autoimmune diseases. Its infection process shared many similarities with the pathogenesis of myasthenia gravis (MG) at cellular and cytokine levels. Recent case reports demonstrated patients present with MG after M. pneumoniae infection. However, no epidemiological studies ever looked into the association between the two. Our study aimed to investigate the relationship between M. pneumoniae infection and subsequent development of MG. In this population-based retrospective cohort study, the risk of MG was analyzed in patients who were newly diagnosed with M. pneumoniae infection between 2000 and 2013. A total of 2428 M. pneumoniae patients were included and matched with the non-M. pneumoniae control cohort at a 1:4 ratio by age, sex, and index date. Cox proportional hazards regression analysis was applied to analyze the risk of MG development after adjusting for sex, age, and comorbidities, with hazard ratios and 95% confidence intervals. The incidence rates of MG in the non-M. pneumoniae and M. pneumoniae cohorts were 0.96 and 1.97 per 10,000 person-years, respectively. Another case-control study of patients with MG (n = 515) was conducted to analyze the impact of M. pneumoniae on MG occurrence as a sensitivity analysis. The analysis yielded consistent absence of a link between M. pneumoniae and MG. Although previous studies have reported that M. pneumoniae infection and MG may share associated immunologic pathways, we found no statistical significance between M. pneumoniae infection and subsequent development of MG in this study.

Macrolide resistance and molecular typing of Mycoplasma pneumoniae infections during a 4 year period in Spain

Background

Mycoplasma pneumoniae (MP) causes community-acquired pneumonia affecting mainly children, and tends to produce cyclic outbreaks. The widespread use of macrolides is increasing resistance rates to these antibiotics. Molecular tools can help in diagnosis, typing and resistance detection, leading to better patient management.

Objectives

To assess the MP genotypes and resistance pattern circulating in our area while comparing serological and molecular diagnosis of MP.

Methods

Molecular and serological diagnosis of MP was performed in 821 samples collected in Badalona (Barcelona, Spain) from 2013 to 2017. Multiple locus variable number tandem repeat analysis (MLVA) and macrolide resistance detection by pyrosequencing were performed in those cases positive by PCR. Presence of respiratory viruses and relevant clinical data were also recorded.

Results

MP was detected in 16.8% of cases by PCR, with an overall agreement with serology of 76%. Eleven different MLVA types were identified, with 4-5-7-2 (50.1%) and 3-5-6-2 (29.2%) being the most abundant, with the latter showing a seasonal increase during the study. A total of 8% of the strains harboured a point substitution associated with macrolide resistance, corresponding mainly to an A2063G 23S rRNA mutation and directly related to previous macrolide therapy. Analysis of respiratory viruses showed viral coinfections in most cases.

Conclusions

Serological and molecular tools combined could improve MP diagnosis and the analysis of its infection patterns. Macrolide resistance is associated with previous therapy. Given that MP pneumonia usually resolves spontaneously, it should be reconsidered whether antibiotic treatment is suitable for all cases.

Atypical Pathogen Distribution in Chinese Hospitalized AECOPD Patients: A Multicenter Cross-Sectional Study

Purpose

The proportion of atypical pathogens in patient with AECOPD within mainland China is unknown. The objectives of this study were to determine the distribution of atypical pathogens among Chinese patients with AECOPD, to evaluate the clinical characteristics of different atypical pathogen infections, and to compare different detection methods for atypical pathogens.

Patients and Methods

Specimens were collected from patients with AECOPD from March 2016 to November 2018 at eleven medical institutions in eight cities in China. Double serum, sputum, and urine samples were obtained from 145 patients. Serological and nucleic acid tests were used to assess for Mycoplasma pneumonia and Chlamydia pneumoniae; serological, urinary antigen, and nucleic acid tests were applied to detect Legionella pneumophila. The clinical characteristics of atypical pathogen-positive and -negative groups were also compared.

Results

The overall positivity rate for Mycoplasma pneumoniae was 20.69% (30/145), with the highest rate being 20.00% (29/145) when determined by passive agglutination.The overall positive rates for Chlamydia pneumoniae and Legionella pneumophila were 29.66% (43/145) and 10.34% (15/145), respectively. The most common serotype of Legionella pneumophila was type 6. The maximum hospitalized body temperature, ratio of eosinophils, C-reactive protein (CRP) level, and procalcitonin (PCT) level of the Mycoplasma pneumoniae-positive group were significantly higher than those of the Mycoplasma pneumoniae-negative group. Patients in the Chlamydia pneumoniae-positive group smoked more, had higher proportions of comorbidities and frequent aggravations in the previous two years than those in the Chlamydia pneumoniae-negative group. Furthermore, the forced expiratory volume in one second to forced vital capacity (FEV₁/FVC) ratio assessment of lung function was higher, and the concentration of arterial blood bicarbonate (HCO₃ ^-) was lower in the Legionella pneumophila-positive group than in the Legionella pneumophila-negative group.

Conclusion

Overall, atypical pathogens play an important role in AECOPD. Regarding the testing method, serological testing is a superior method to nucleic acid testing.

Time to Mycoplasma Pneumoniae RNA Clearance for Wheezy vs. Non-Wheezy Young Children with Community-Acquired Pneumonia

OBJECTIVES

We sought to investigate the dynamics of Mycoplasma pneumoniae (Mp) RNA in hospitalized young children with community-acquired pneumonia (CAP) and to explore whether Mp RNA clearance differed for wheezy and non-wheezy group after the onset of azithromycin treatment.

METHODS

We included hospitalized young children (1-72 months of age) with CAP caused by Mp infection. Mp RNA was detected as soon as the patient was admitted and the dynamics of Mp-RNA were monitored after the beginning of azithromycin treatment on Days 4, 7, 14 and 28.

RESULTS

Among 40 hospitalized young children with Mycoplasma pneumoniae pneumonia (Mpp), 16 had wheezing. Time to first positive Mp-RNA confirmation after symptom onset of Mpp was similar for the wheezy group (median 7 days, interquartile range 7-10.5) and the non-wheezy group (median 7 days, interquartile range 5.8-8.3). The duration of positive Mp-RNA detection after the onset of azithromycin treatment was shorter among the wheezy group than in the non-wheezy group (median 4 vs. 7 days; hazard ratio 2.083; 95% confidence interval: 1.023-4.244).

CONCLUSIONS

Mp-RNA clearance was significantly faster among Mpp young children with wheezing than in those without wheezing after the onset of azithromycin treatment.Lay summaryWe sought to investigate the dynamics of Mycoplasma pneumoniae (Mp) RNA in hospitalized young children with community-acquired pneumonia and to explore whether Mp RNA clearance differed for wheezy and non-wheezy group after the onset of azithromycin treatment. Our study suggested that Mp-RNA clearance was significantly faster among Mycoplasma pneumoniae pneumonia young children with wheezing than in those without wheezing after the onset of azithromycin treatment.

First report of macrolide-resistant and -susceptible Mycoplasma pneumoniae clinical strains isolated from a single case

OBJECTIVES

The aim of this study was to investigate the biological characteristics and effect of antibiotic treatment for different Mycoplasma pneumoniae isolates co-infecting the same patient.

METHODS

Two throat swab specimens from a single patient, on the day of admission (Sp01) and discharge (Sp13), were liquid cultured and subcultured on agar medium to obtain M. pneumoniae monoclones. The 23S rRNA gene of 50 monoclones from specimens Sp01 and Sp13 were analysed. Real-time PCR assay was used for detection of mutations and genotyping. Two typical monoclones were isolated for antimicrobial susceptibility testing.

RESULTS

Genotype 1 monoclones accounted for 70.8% (34/48) in Sp01 and 95.7% (44/46) in Sp13. All genotype 1 monoclones were of the 4-5-7-2 multilocus variable-number tandem-repeat analysis (MLVA) type, while all genotype 2 monoclones were 3-5-6-2 MLVA type. The genotype 1 monoclone, which harboured the A2063G mutation in 23S rRNA gene, was resistant to erythromycin and azithromycin in vitro, whilst genotype 2, which did not carry the mutation, was susceptible to macrolides. The proportion of macrolide-resistant M. pneumoniae monoclones in the specimen cultures collected rose from 70.8% to 95.7% at the time of discharge.

CONCLUSION

This is the first report on the isolation of macrolide-resistant and -susceptible strains of M. pneumoniae from the same patient. After treatment, the proportion of macrolide-resistant M. pneumoniae increased, but the patient still carried viable macrolide-susceptible strains, meaning that the macrolide-susceptible strains did not disappear completely.

Emerging Options for the Diagnosis of Bacterial Infections and the Characterization of Antimicrobial Resistance

Precise and rapid identification and characterization of pathogens and antimicrobial resistance patterns are critical for the adequate treatment of infections, which represent an increasing problem in intensive care medicine. The current situation remains far from satisfactory in terms of turnaround times and overall efficacy. Application of an ineffective antimicrobial agent or the unnecessary use of broad-spectrum antibiotics worsens the patient prognosis and further accelerates the generation of resistant mutants. Here, we provide an overview that includes an evaluation and comparison of existing tools used to diagnose bacterial infections, together with a consideration of the underlying molecular principles and technologies. Special emphasis is placed on emerging developments that may lead to significant improvements in point of care detection and diagnosis of multi-resistant pathogens, and new directions that may be used to guide antibiotic therapy.

Comparison of Nucleic Acid Amplification and IgM Tests for the Diagnosis of Mycoplasma pneumoniae Infection in Children During a Recent Korean Outbreak

OBJECTIVE

In the absence of standardized methods for Mycoplasma pneumoniae detection, we evaluated the diagnostic value of polymerase chain reaction (PCR) and IgM assays for detecting M. pneumoniae infection in children during a recent Korean outbreak.

METHODS

The diagnostic performances of PCR and IgM assays for M. pneumoniae in 1,109 clinical specimens were evaluated by the Japanese Respiratory Society (JRS) scoring system as an interim reference standard.

RESULTS

The level of agreement between both tests was fair. As analyzed by the JRS scoring system, the sensitivity of PCR was 45.2% in the group aged <5 years, 86.8% in the group aged 5 years to 10 years group, and 72.2% in the group aged 10 years to 18 years; the sensitivity of the IgM assay was 66.8%, 71.4%, and 55.6% in each group, respectively.

CONCLUSION

The sensitivity of PCR is relatively low but is superior to that of IgM assays such that diagnostic performance can be improved by both test methods in patients aged <5 years.

Respiratory pathogens and acute chest syndrome in children with sickle cell disease

BACKGROUND

Acute chest syndromes (ACS) may be associated with upper respiratory tract infections, but the epidemiology of viral and intracellular respiratory pathogens in children with sickle cell disease (SCD) is not precisely known. The aim of this study was to describe the epidemiology of viral and intracellular respiratory pathogens in children with SCD presenting with fever and/or ACS.

MATERIALS AND METHODS

An observational, prospective, single-centre cohort study with nested case-control analysis was conducted on children with SCD admitted from October 2016 to October 2017 for fever and/or ACS to the paediatric department of Robert Debré university hospital, Paris, France. They were screened for 20 respiratory pathogens by a multiplex PCR in the nasopharynx (FilmArray).

RESULTS

We included 101 children. M/F sex ratio of 0.45. The median age was 3.2 years (IQR: 1.4-8.2). At least one pathogen was isolated in 67 patients (67%). The most frequent viruses were as follows: rhinovirus (n=33), adenovirus (n=14), respiratory syncytial virus (n=13) and parainfluenza viruses (n=11). Mycoplasma pneumoniae was detected in one case. Twenty-three (23%) presented with or developed ACS. A nested case-control analysis was performed, after pairing ACS with non-ACS children for age and inclusion period. There was no statistical association between any viral detection or multiple viral infection, and ACS (p=0.51) even though parainfluenza viruses were twice as common in ACS.

CONCLUSIONS

Viral detection in febrile children with SCD is frequent, but its association with ACS was not demonstrated. In this study, M. pneumoniae was rare in young children with SCD experiencing ACS.

Recurrent reactive infectious mucocutaneous eruption (RIME): Insights from a child with three episodes

Reactive infectious mucocutaneous eruption (RIME) was recently proposed to replace the term Mycoplasma pneumoniae (MP)-induced rash and mucositis to account for the fact that non-MP pathogens may also cause rash and mucositis. In this report, we describe a unique case of recurrent RIME featuring a total of three episodes. As two of the episodes demonstrated contemporaneous infection with MP and group A streptococcus or influenza B, this case lends further support to use of the term RIME. In addition, although RIME typically involves at least two mucous membranes, this case shows that recurrent episodes may fall into the rare exception in which mucositis is limited to one site.

Validation of a Loop-Mediated Isothermal Amplification Assay for Rapid Diagnosis of Invasive Pneumococcal Disease

Current molecular PCR-based techniques used for detecting Streptococcus pneumoniae, the causative pathogen of invasive pneumococcal disease (IPD), are accurate but have a run time of several hours. We aimed to develop and validate a novel real-time loop mediated amplification (LAMP) assay for rapid detection of pneumococcus in normally sterile samples with accuracy comparable to a gold standard real-time PCR. Conserved regions of lytA were used for the design of the LAMP test. Analytical validation included assessment of linearity, limit of detection (LOD), intra-assay and inter-assay precision and analytical specificity, which was evaluated by using reference strain S. pneumoniae R6 and a quality control panel. Clinical performance was assessed on all samples collected from children with suspicion of IPD attended in Hospital Sant Joan de Deu (Barcelona, Spain) during the period April-September 2015. Fresh samples were analyzed after DNA extraction. The following values of analytical parameters were determined: linearity within the range 10⁸-10⁴ copies/mL; limit of detection, 5·10³ copies/mL; intra- and inter-assay precision measured by mean coefficient of variance, 3.61 and 6.59%; analytical specificity, 9/9 pathogens similar to S. pneumoniae and 14/14 strains of different S. pneumoniae serotypes correctly identified as negative and positive results, respectively. Diagnostic sensitivity and specificity values were 100.0 and 99.3%. Median time of DNA amplification was 15 min. The new LAMP assay showed to have similar accuracy as PCR while being 5-fold faster and could become a useful diagnostic tool for early diagnosis of IPD.

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

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

Hepatocyte growth factor can guide treatment of Mycoplasma pneumoniae pneumonia in children

The objective of the present study was to explore the role of hepatocyte growth factor (HGF) in directing treatment of Mycoplasma pneumoniae pneumonia (MP). Serum levels of HGF were assessed using ELISA in 65 pediatric patients with MP, 42 with bacterial pneumonia and 30 healthy controls. Serum levels of C-reactive protein (CRP), the standard guide for MP treatment, were also examined in severe and non-severe MP. The sensitivity and specificity of HGF and CRP in assessing the outcome of azithromycin treatment of MP were compared using receiver operating characteristic curves. HGF levels were elevated in MP and bacterial pneumonia patients compared with healthy controls. HGF levels were also significantly higher in severe MP than in non-severe MP. HGF showed higher sensitivity and specificity than CRP in assessing outcomes of azithromycin treatment of MP. The results of the present study indicated that HGF may be used to detect severe MP and to direct its management. Furthermore, HGF may be better predictive marker to assess the effectiveness of azithromycin treatment of MP than CRP.

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.

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

Background

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

Methods

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

Results

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

Conclusions

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

Paediatric critical illness associated with respiratory infection: a single-centre, retrospective cohort study

OBJECTIVES

To describe critically ill children with respiratory infections, classify them by infection syndrome type and determine the prevalence of Mycoplasma pneumoniae detection.

STUDY DESIGN

A retrospective, single-centre cohort study. All children aged 2 months-18 years with presumed respiratory infection who were admitted to a tertiary hospital paediatric intensive care unit (PICU) between September 2015 and October 2016 were eligible. Subjects were grouped by clinical syndrome (viral respiratory infection, asthma exacerbation, undifferentiated/uncomplicated pneumonia, pneumonia complicated by effusion/empyema and 'other'). All subjects had nasopharyngeal swabs tested for respiratory viruses, M. pneumoniae and Chlamydia pneumoniae.

RESULTS

There were 221 subjects; the median age was 3.1 years; 44% were female; and 78% had medical comorbidities. The majority (75%) was treated with antibiotics, most often ceftriaxone (90% of treated children). Those with any pneumonia were significantly less likely to have a respiratory virus identified in their nasopharynges and had significantly higher C reactive protein (CRP) values than those in the viral infection and asthma groups. There were 10 subjects in whom M. pneumoniae was detected (4.5%, 95% CI 2.2% to 8.2%). Mycoplasma-positive children were older (difference 3.5 years, 95% CI 0.66 to 6.4 years) and had fewer viral coinfections (30% compared with 69%, p=0.02). The prevalence of Mycoplasma infection in children aged >5 years with any pneumonia was 13.2% (95%CI 4.4% to 28%).

CONCLUSIONS

The majority of participants had respiratory viruses detected and were treated with broad-spectrum antibiotics. Differences in CRP and viral prevalence were observed between children with different infection syndrome types. M. pneumoniae infection was not rare in school-aged children with pneumonia admitted to the PICU. Attention to antibiotic treatment and rapid diagnostic testing for Mycoplasma in older, critically ill children should be considered to optimise management and avert morbidity and mortality from respiratory infection.

The Association Between Mycoplasma pneumoniae and Chlamydia pneumoniae, a Life-Threatening Condition in Small Children-A Case Report and a Review of the Literature

Mycoplasma pneumoniae (MP) and Chlamydia pneumoniae (CP) are two atypical pathogens that may result in mild, moderate or severe acute respiratory infections. We report the case of a 2 years and 9-month-old male child admitted with prolonged fever, dry cough, and shortness of breath for which he underwent symptomatic treatment. The laboratory tests showed leukocytosis with neutrophilia, anemia, and elevated inflammatory biomarkers and the thoracic radiography revealed pleural effusion raising the suspicion of inferior right pneumonia. Although we the initial evolution was favorable being treated with 3rd class cephalosporin and Oxacillin, on the 8th day of admission the fever and the acute phase reactants levels increased as well as the quantity of the pleural effusion, requiring surgical drainage. We ruled out lung tuberculosis, but we identified positive IgM for both MP and CP. Based on these findings we changed the antibiotic therapy on Levofloxacin for 10 days with favorable evolution. MP and CP are two atypical pathogen that are difficult to be diagnosed due to their slow-growing pattern. Despite their self-limiting feature, the association between them might carry a vital risk in small children, especially in the lack of a proper and timely diagnosis.

High Mycoplasma pneumoniae loads and persistent long-term Mycoplasma pneumoniae DNA in lower airway associated with severity of pediatric Mycoplasma pneumoniae pneumonia

Background

An increased number of refractory mycoplasma pneumoniae (MP) pneumonia (MPP) cases have been reported. However the duration of MP infection in lower airway and the course of anti-MP treatment remains unclear.

Methods

We retrospectively reviewed the medical records of 94 MPP children. Patients were classified into two groups. The long-term group (Group LT) was defined as bronchoalveolar lavage fluid (BALF) remained MP-positive by PCR after 30 days of the disease course. The non-long-term group (Group NLT) was defined as BALF became MP-negative by PCR within 30 days of disease and patients who only needed one bronchoscopy lavage therapy. MP loads, clinical outcomes were analyzed along with other clinical measurements.

Results

The average levels of inflammatory markers such as C reactive protein and lactate dehydrogenase in Group LT were significantly higher than those in Group NLT. Airway and lung damage in Group LT were more severe than Group NLT. 28 patients developed necrotizing pneumonia and 8 patients developed pulmonary embolism in Group LT. Mean maximum MP loads in BALF were 10^{7.46 ± 0.93} and 10^{4.86 ± 0.93} in Groups LT and NLT, respectively. There was persistent MP DNA in Group LT, even lasted for 120 days. One severe MPP patient in Group LT had MP-associated bloodstream infection. After 3 months of follow-up, chest imaging revealed incomplete absorption of pulmonary consolidation in 33 patients of Group LT [including 13 airway obliterans (AO) patients] and in 7 patients of Group NLT (including 2 AO patients).

Conclusion

MP loads of BALF were associated with the subsequent duration of MP DNA in lower airway. High MP loads and persistent long-term MP DNA in lower airway were associated with severity of pediatric MPP.

The role of mixed Mycoplasma and Herpesvirus infections in case of skin lesions in children

Numerous literature data show the role of mycoplasma infection in the development of non-respiratory lesions of various organs and systems, including the skin. Herpesvirus and mycoplasma infections can trigger the development of immune-mediated inflammatory reactions of the skin and mucous membranes — erythema multiforme exudative, Stevens-Johnson syndrome, vesicular pustular dermatosis — Sneddon-Wilkinson syndrome, etc.

In order to study the frequency and nature of skin lesions with mycoplasmosis combined with herpesvirus infection, 45 patients aged 3 to 15 years of life were observed. A comprehensive clinical and laboratory study revealed skin lesions in 27 patients associated with current mycoplasma and herpesvirus infections. Thus, multiforme exudative erythema in the small form variant was diagnosed in 13 patients, skin vasculitis in 4, hemorrhagic purpura in 3, urticaria rash in 3, erythema nodosum in 2, mucositis in 2 children. In 18 children, a combined mycoplasma and herpesvirus infection was established. In 9 children, a mono infection was detected (in 5 — herpes virus and in 4 — mycoplasma).

All observed patients showed antibodies to smooth muscle antigens in titers from 1:80 to 1:160 (normal 1:40) and in the vast majority (in 24 patients) — antibodies to vascular endothelial antigens in titers from 1:80 to 1:320 (with the norm of 1:40). Compaction of the intima-media complex was detected in 6 patients with monoinfection and in 16 patients with co-infection, according to ultrasound duplex scanning of the vessels of the brachiocephalic department.

Thus, for various immuno-inflammatory, allergic skin diseases, screening for infections, in particular, mycoplasma and herpesvirus, is necessary to optimize treatment.

Multiplex Platforms for the Identification of Respiratory Pathogens: Are They Useful in Pediatric Clinical Practice?

Respiratory tract infections (RTIs) are extremely common especially in the first year of life. Knowledge of the etiology of a RTI is essential to facilitate the appropriate management and the implementation of the most effective control measures. This perspective explains why laboratory methods that can identify pathogens in respiratory secretions have been developed over the course of many years. High-complexity multiplex panel assays that can simultaneously detect up to 20 viruses and up to four bacteria within a few hours have been marketed. However, are these platforms actually useful in pediatric clinical practice? In this manuscript, we showed that these platforms appear to be particularly important for epidemiological studies and clinical research. On the contrary, their routine use in pediatric clinical practice remains debatable. They can be used only in the hospital as they require specific equipment and laboratory technicians with considerable knowledge, training, and experience. Moreover, despite more sensitive and specific than other tests routinely used for respiratory pathogen identification, they do not offer significantly advantage for detection of the true etiology of a respiratory disease. Furthermore, knowledge of which virus is the cause of a respiratory disease is not useful from a therapeutic point of view unless influenza virus or respiratory syncytial virus are the infecting agents as effective drugs are available only for these pathogens. On the other hand, multiplex platforms can be justified in the presence of severe clinical manifestations, and in immunocompromised patients for whom specific treatment option can be available, particularly when they can be used simultaneously with platforms that allow identification of antimicrobial resistance to commonly used drugs. It is highly likely that these platforms, particularly those with high sensitivity and specificity and with low turnaround time, will become essential when new drugs effective and safe against most of the respiratory viruses will be available. Further studies on how to differentiate carriers from patients with true disease, as well as studies on the implications of coinfections and identification of antimicrobial resistance, are warranted.

Molecular testing for respiratory pathogens in sickle cell disease adult patients presenting with febrile acute chest syndrome

BACKGROUND

Differentiating acute chest syndrome (ACS) from community-acquired pneumonia (CAP) is challenging in adults presenting with major sickle cell disease (SCD) (semiological similarity, rare microbiological documentation). We aimed to assess the usefulness of nucleic acid amplification test (NAAT) for respiratory pathogens, in combination with standard bacteriological investigations, in febrile ACS adult patients presenting with major SCD.

METHODS

We performed a prospective, monocentric, observational study of 61 SCD adults presenting with febrile ACS from February 2015 to April 2016. Systematic blood, urine, and respiratory specimens were collected, before antibiotic initiation, for culture, urinary antigen tests, serology, and NAAT for respiratory pathogens.

RESULTS

A pathogen was detected in 12 febrile ACS (19.7%): four viruses (6.6%) (Rhinovirus; Influenza A/B), seven bacteria (11.4%) (S. aureus, S. pneumoniae, K. pneumoniae, L. pneumophila, M. pneumoniae), one mixed infection (1.6%) (S. aureus and Influenza B). NAAT only detected L. pneumophila in one case (serogroup 2). Apart from a significantly shorter antibiotic therapy duration (6.1 vs. 7.8 days, P=0.045), no difference was observed between undocumented and microbiologically-documented febrile ACS.

CONCLUSION

Using NAAT for the detection of respiratory pathogens in adults presenting with SCD slightly improved the microbiological diagnostic of febrile ACS, although respiratory infections are not the main etiological factor.

Pediatric toxic epidermal necrolysis treated successfully with infliximab

Successful management of toxic epidermal necrolysis (TEN) with tumor necrosis factor-α inhibitors has been described in adults. We present a case of a 7-year-old boy with infection-associated TEN, diagnosed by typical clinical and histopathological features, most likely caused by Mycoplasma pneumoniae. Treatment with a single dose of infliximab 5 mg/kg intravenously on day 5 after the onset of symptoms was followed by cessation of all blister formation over 3 days and complete resolution within a week. Sequelae were mild, consisting of postinflammatory hyperpigmentation and dry eyes.

The Role of B Cells in Carriage and Clearance of Mycoplasma pneumoniae From the Respiratory Tract of Mice

Background

Carriage of Mycoplasma pneumoniae (Mp) in the nasopharynx is considered a prerequisite for pulmonary infection. It is interesting to note that Mp carriage is also detected after infection. Although B cells are known to be involved in pulmonary Mp clearance, their role in Mp carriage is unknown.

Methods

In this study, we show in a mouse model that Mp persists in the nose after pulmonary infection, similar to humans.

Results

Infection of mice enhanced Mp-specific immunoglobulin (Ig) M and IgG levels in serum and bronchoalveolar lavage fluid. However, nasal washes only contained elevated Mp-specific IgA. These differences in Ig compartmentalization correlated with differences in Mp-specific B cell responses between nose- and lung-draining lymphoid tissues. Moreover, transferred Mp-specific serum Igs had no effect on nasal carriage in B cell-deficient μMT mice, whereas this enabled μMT mice to clear pulmonary Mp infection.

Conclusions

We report the first evidence that humoral immunity is limited in clearing Mp from the upper respiratory tract.

Pooled analysis of nuclear acid sequence-based amplification for rapid diagnosis of Mycoplasma pneumoniae infection

Background

Mycoplasma pneumoniae(M pneumoniae) is a common human etiology of respiratory infections. Nuclear acid sequence‐based amplification (NASBA) shows good value for the detection of M pneumoniae that surpasses PCR. However, the optimal detection technology still remains to be identified. The purpose of this meta‐analysis was to systematically evaluate the overall accuracy of NASBA for diagnosing M pneumoniae infections.

Methods

The databases PubMed, Cochrane Library, Google Scholar, CNKI, Wang Fang, and Baidu Scholar were comprehensively searched from their initiation date to December 2017 for NASBA in the diagnosis of M pneumoniae infection. Meta‐DiSc 1.4 statistical software was used to evaluate the sensitivity (SEN), specificity (SPE), negative likelihood ratio (−LR), positive likelihood ratio (+LR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC). RevMan 5.2 statistical software was used for quality evaluation of the included articles. Publication bias was evaluated by funnel plot.

Results

Six articles with high quality, including 10 studies, were finally included in this meta‐analysis. The combined statistics results for the diagnosis of M pneumoniae infection by NASBA were 0.77 (SEN, 95% CI: 0.71 to 0.82); 0.98 (SPE, 95% CI: 0.98 to 0.99); 0.22 (‐LR, 95% CI: 0.13 to 0.39); 50.38 (+ LR, 95% CI: 21.85 to 116.17); 292.72 (DOR, 95% CI: 95.02 to 901.75); and 0.9875 (the area under the curve of SROC).

Conclusion

Nuclear acid sequence‐based amplification is a reliable technique to diagnose M pneumoniae infection. However, whether it can replace PCR and serology need to be further studied.

M. pneumoniae and C. pneumoniae are no relevant pathogens in critically ill patients with hospital-acquired respiratory tract infections

PURPOSE

To assess the incidence of Mycoplasma pneumoniae and Chlamydia pneumoniae in the pathogenesis of hospital-acquired respiratory tract infections (RTIs) in critically ill patients.

METHODS

This is a retrospective cohort study of all ICU-patients ≥ 18 years with RTI who underwent conventional culture techniques and PCR testing for both M. pneumoniae and C. pneumoniae from respiratory tract specimens (bronchoalveolar lavage or tracheobronchial aspirates) between January 2013 to May 2017 at the Jena University Hospital.

RESULTS

In total, 314 patients were included in the analysis. Of these, 210 (66.9%) patients were diagnosed with HAP, 65 (20.7%) with VAP and 39 (12.4%) with VAT. Overall, 73 (30.7%) patients were on mechanical ventilation on the day of microbiological examination. PCR-testing for M. pneumoniae was positive in two patients (0.6%) and for C. pneumoniae in zero patients.

CONCLUSIONS

Our study shows that the incidence of M. pneumoniae and C. pneumoniae in the pathogenesis of hospital-acquired RTIs in critically ill patients is negligible. The results support the recommendations of the guidelines not to perform empiric therapy covering these pathogens.

Multiplexed detection and identification of respiratory pathogens using the NxTAG® respiratory pathogen panel

•

NxTAG chemistry offers an easy workflow, low hands-on-time and scalable throughput.

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All post-extraction assay steps take place in a single, closed tube.

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Clinical performance of NxTAG RPP is comparable to that of the xTAG RVP assay.

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Analytical performance is also similar or better than xTAG and xTAG FAST assays.

The Luminex® NxTAG® Respiratory Pathogen Panel (NxTAG RPP) is an IVD-cleared assay for the simultaneous detection and identification of nucleic acids from 18 respiratory viruses and 2 (or 3 outside of the U.S.) atypical bacterial pathogens in nasopharyngeal swabs. Its scalability allows concurrent testing of up to 96 samples in a single batch. Nucleic acid extracted from 200 µL of raw specimen using the easyMAG® extractor is added directly to pre-plated, lyophilized bead reagents (LBRs), where multiplexed RT-PCR and hybridization to MagPlex-TAG™ microspheres occurs within a sealed reaction well using a single cycling program. Data acquisition is done on the MAGPIX® instrument which reads and sorts the reaction products directly from the sealed well following transfer of the assay plate from the thermal cycler. NxTAG is the newest innovation in bead-based nucleic acid chemistry developed by Luminex. Here we provide the detailed assay protocol and present data which describe the clinical and analytical performance characteristics of NxTAG RPP.

Clinical features of Mycoplasma pneumoniae coinfection and need for its testing in influenza pneumonia patients

Background

To investigate the clinical features of coinfection due to Mycoplasma pneumoniae (M. pneumoniae), a common copathogen in influenza, in influenza pneumonia patients.

Methods

We reviewed 4,465 patients with influenza who visited a tertiary care hospital emergency department in Seoul (Korea) from 2010 through 2016, and underwent immunoglobulin M (IgM) serology or polymerase chain reaction (PCR) for M. pneumoniae. Influenza pneumonia was defined as laboratory-confirmed influenza plus radiographic pneumonia. Patients with healthcare-associated pneumonia or non-mycoplasma bacterial coinfection were excluded. Clinical, laboratory, and radiographic findings and outcomes of the influenza pneumonia patients with and without M. pneumoniae coinfection were compared. Multivariable logistic regression analysis was performed to identify factors associated with the coinfection.

Results

Of 244 influenza pneumonia patients, 41 (16.8%) had M. pneumoniae coinfection. These patients were younger with a higher frequency of age of 5-10 years, and had higher white blood cell (WBC) and lymphocyte counts; lower concentration of C-reactive protein (CRP). The coinfection had no association with specific radiographic findings and poor outcome. Multivariable analysis showed the age of 5-10 years (adjusted odds ratio, 18.83; 95% confidence interval, 5.899-60.08; P<0.001) as the factor associated with the coinfection.

Conclusions

M. pneumoniae coinfection in influenza pneumonia may be associated with the age of 5-10 years, and otherwise clinically indistinct from influenza pneumonia without the coinfection. This finding suggests the need for M. pneumoniae testing in patients aged 5-10 years with influenza pneumonia.

A case report of Legionella and Mycoplasma pneumonia: Co-incidence or co-infection?

RATIONALE

Concurrent or sequential coinfections of Legionella pneumophila and Mycoplasma pneumoniae have been reported in the past though infrequently. Distinguishing a true co-infection from cross reactivity is often challenging as the diagnosis is mostly dependent on serological testing.

PATIENT CONCERNS

A 77-year-old male presented with worsening dyspnea, cough with yellow sputum, diarrhea and fever of 2-days duration. Patient had history of chronic obstructive pulmonary disease (COPD) on home oxygen, bronchiectasis, rheumatoid arthritis (on methotrexate and leflunomide), treated pulmonary tuberculosis and 30-pack-year smoking. Chest X-ray showed bilateral interstitial changes with left lower lobe infiltrate. On day 5, his urine antigen for L pneumophila serogroup 1 was reported positive. The following day his serum M pneumoniae IgM antibody titers were reported elevated at 6647 U/mL. Patient was started on antibiotics and placed on non-invasive positive pressure ventilation.

DIAGNOSIS

The patient was diagnosed with possible Legionella and Mycoplasma co-infection.

OUTCOMES

Sputum Mycoplasma polymerase chain reaction (PCR) and serum cold agglutinins were obtained on day 6 and later reported negative. He was treated with azithromycin for 10 days with clinical improvement.

LESSONS

Serological testing alone is an indirect measure with poor sensitivity and specificity and has its own limitations. Urine antigen detection confirms L pneumophila serogroup 1 infection in a patient with suggestive symptoms. However, diagnosis of M pneumonia should be based on combination of tests including serology and PCR to confirm true co-infection.

The diagnostic value of serological studies in pediatric patients with acute Mycoplasma pneumoniae infection

BACKGROUND

Mycoplasma pneumoniae is a common pathogen of respiratory tract infections in pediatric patients. Serological studies are traditional methods for the diagnosis. However, early diagnosis of M. pneumoniae infections remains problematic. We investigate the value of early serum immunoglobulin A (IgA), in addition to immunoglobulin G (IgG), and immunoglobulin M (IgM) levels, in children infected with M. pneumoniae.

METHODS

From August 2016 to February 2017, we enrolled pediatric patients based on both clinical symptoms and chest x-ray, and confirmed by positive throat culture for M. pneumoniae. Serum titers of M. pneumoniae IgM, IgG, and IgA during the acute phase were checked. All respiratory samples were further analyzed by polymerase chain reaction (PCR). Diagnostic values of different tests were evaluated.

RESULTS

Fifty-six patients fulfilled the diagnostic criteria, with a median age of 4.84 years. Most of them (89.3%) were enrolled within 7 days of disease onset. PCR was positive in 71.4% of the study population. Early IgG samples were of limited value in diagnosing M. pneumoniae infection, of which 89.3% showed a negative result. Positive rates of early serum IgA and IgM were 48.2% and 46.4%, respectively. In combination with IgA and/or IgM, the sensitivity increased to 71.4% during their early clinical course.

CONCLUSIONS

In the pediatric population, combined serological tests of M. pneumoniae IgA and IgM, offer an accurate method of early diagnosis comparable to that of PCR, and can be an alternative choice for prompt detection of mycoplasma infections when PCR and culture are not available.

Use of serology and polymerase chain reaction to detect atypical respiratory pathogens during acute exacerbation of chronic obstructive pulmonary disease

BACKGROUND/AIMS

To use serological and multiplex polymerase chain reaction (PCR) assays to examine sputum samples from patients experiencing acute exacerbation of chronic obstructive pulmonary disease (AECOPD) for the presence of atypical pathogens, including Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila.

METHODS

From September 2012 to February 2014, 341 patients with AECOPD attending outpatient clinics were enrolled as part of a randomized, double-blind, multicenter study. A commercial enzyme-linked immunosorbent assay was used to measure serum immunoglobulin M (IgM) and IgG antibody titers on the first day of the study and at 36 days post-enrollment. Multiplex PCR was used to test sputum samples for the presence of atypical pathogens. A urinary antigen test for L. pneumophila was performed on the first day.

RESULTS

Nineteen patients (5.6%) showed serological evidence of acute infection with M. pneumoniae. Also, one and seven patients (2%) showed serological evidence of acute infection with C. pneumoniae and L. pneumophila, respectively. All DNA samples were negative for M. pneumoniae, C. pneumoniae, and L. pneumophila according to PCR. Only one urine sample was positive for L. pneumophila antigen, but serologic evidence was lacking.

CONCLUSION

Serological testing suggested that infection by atypical pathogens during AECOPD was relatively uncommon. In addition, PCR provided no direct evidence of infection by atypical pathogens. Thus, atypical pathogens may not be a major cause of AECOPD in South Korea.

Mycoplasma pneumoniae DNA detection and specific antibody class response in patients from two tertiary care hospitals in tropical Sri Lanka

PURPOSE

Respiratory tract infections are a major cause of global morbidity and mortality. Pneumonia is the ninth leading cause of mortality in Sri Lanka. Atypical pathogens cause about one-fifth of community-acquired pneumonia, while Mycoplasma pneumoniae accounts for about 50 %. This study aimed to determine the seroprevalence of M. pneumoniae respiratory tract infections in Sri Lanka while attempting to understand the relationships between the serology and PCR.

METHODOLOGY

Paired sera from 418 adult patients (pneumonia, n=97; bronchitis, n=183; pharyngitis, n=138) and 87 healthy controls were studied. IgM, IgG and IgA antibodies were tested by M. pneumoniae enzyme-linked immunosorbent assay (ELISA). Positive IgM and or IgG seroconversion was considered to be seropositive. M. pneumoniae DNA were tested by PCR in age and gender-matched seropositives and seronegatives.

RESULTS

M. pneumoniae IgG was in 14.4 % (14/97), 6.0 % (11/183) and 1.5 % (2/138) of pneumonia, bronchitis and pharyngitis patients, respectively, whilst IgM was in 6.2 % (6/97), 1.1 % (2/183) and 0 % (0/138), respectively. Amongst the pneumonia seropositives, 64.7 % (11/17) showed IgG alone, 17.5 % (3/17) showed IgM alone and 17.5 % (3/17) showed IgM and IgG. Amongst the bronchitis seropositives, 84.6 % (11/13) had IgG alone and 15.4 % (2/13) had IgM alone. In the pharyngitis seropositives, only IgG was detected 100 % (2/2). M. pneumoniae DNA was in 52.2 % (12/23) of seropositives and 15.4 % (4/26) of seronegatives. In pneumonia or bronchitis patients, specific DNA was in 77.8 % (7/10) and 50 % (6/12) of patients, respectively. M. pneumoniae DNA was not found in pharyngitis patients. Of the seropositive PCR-negative pneumonia patients, 66.7 % (2/3) showed IgG alone and 33.3 % (1/3)showed IgM alone. In bronchitis patients, 83.3 % (5/6) showed IgG alone and 16.7 % (1/6) showed IgM alone. Of the seronegative PCR-positive patients, 16.7 % (2/12) had pneumonia and 18.2 % (2/11) had bronchitis.

CONCLUSION

The serological evidence for M. pneumoniae infection in Sri Lanka comprised the following prevalences: 17.5 % (17/97), 7.1 % (13/183) and 1.4 % (2/138) in adults with pneumonia, bronchitis or pharyngitis, respectively. M. pneumoniae DNA was in 52.2 % (12/23) of seropositives and 15.4 % (4/26) of seronegatives. IgG was predominant in PCR positives and negatives.

Guideline for Antibiotic Use in Adults with Community-acquired Pneumonia

Community-acquired pneumonia is common and important infectious disease in adults. This work represents an update to 2009 treatment guideline for community-acquired pneumonia in Korea. The present clinical practice guideline provides revised recommendations on the appropriate diagnosis, treatment, and prevention of community-acquired pneumonia in adults aged 19 years or older, taking into account the current situation regarding community-acquired pneumonia in Korea. This guideline may help reduce the difference in the level of treatment between medical institutions and medical staff, and enable efficient treatment. It may also reduce antibiotic resistance by preventing antibiotic misuse against acute lower respiratory tract infection in Korea.

Contemporary Situation of Community-acquired Pneumonia in China: A Systematic Review

The prevalence and microbial pattern reported for Community-acquired pneumonia (CAP) differ considerably and contemporary situation remains changing over time. We therefore searched both international and domestic databases for relevant references and pooled incidence of CAP and etiological distribution were estimated separately between children and adults groups. The results showed that CAP remained a major public health issue in China, with a relatively higher incidence than that reported in Western countries. Although pathogens were not detected in nearly half of patients, Mycoplasma pneumoniae remained to be the most frequently detected agent across age groups, the detection yield of which was lower than that reported from other countries. Notably, the incidence of influenza virus A in adults was almost four times higher than that in children while the prevalence of respiratory syncytial virus was much less common in adults than that in children. Despite some limitations, the value of this review, approaching to systematically review grey published data, is to sketch out the contemporary epidemiological and etiological situation of CAP in our country, which could be useful to help policymakers and clinicians make informed choices and to inspire future studies and surveillance.

Evaluation of the Virclia® automated chemiluminescent immunoassay system for diagnosing pneumonia caused by Mycoplasma pneumoniae

BACKGROUND

Mycoplasma pneumoniae is considered an important etiologic agent of community-acquired pneumonia (CAP) in outpatients. We aimed to evaluate the diagnostic accuracy of a quick automated chemiluminescent immunoassay (CLIA) for M. pneumoniae in a population-based prospective study of CAP.

METHODS

A total of 137 outpatients diagnosed with CAP were included in the study. Acute- and convalescent phase sera were analyzed for IgG and IgM to M. pneumoniae with both CLIA (VirClia^® ) and ELISA immunoassays. Conventional serological criteria by quantitative ELISA were considered as reference standard. Sensitivity and specificity of the assay were assessed with the construction of receiver operating characteristic (ROC) curves, and the kappa index was used to evaluate the accuracy of the IgG and IgM determinations in the acute phase.

RESULTS

Thirty-eight patients were diagnosed with pneumonia by M. pneumoniae. ROC curves for IgG and IgM of convalescent and acute phase (C/A) quotients by the CLIA and ELISA assays were comparable. Specifically, for the CLIA, the best C/A quotient for IgG was 2.617 (sensitivity, 94.9%; specificity, 99.9%), and for IgM 1.400 (sensitivity, 65.8%; specificity, 100%). Regarding the acute phase, the best diagnostic accuracy for the CLIA was obtained with an IgG index of 1.120 (sensitivity, 89.5%; specificity, 73.7%). The CLIA was very simple to execute and required a minimum sample handling.

CONCLUSION

The accuracy of the Virclia^® assay for the diagnosis of M. pneumoniae infection in outpatients with CAP was equivalent to the quantitative ELISA. The CLIA was quicker to perform and displayed better analytic workability than conventional ELISA.

Modelling persistent Mycoplasma pneumoniae infection of human airway epithelium

Mycoplasma pneumoniae is a human respiratory tract pathogen causing acute and chronic airway disease states that can include long-term carriage and extrapulmonary spread. The mechanisms of persistence and migration beyond the conducting airways, however, remain poorly understood. We previously described an acute exposure model using normal human bronchial epithelium (NHBE) in air-liquid interface culture, showing that M. pneumoniae gliding motility is essential for initial colonisation and subsequent spread, including localisation to epithelial cell junctions. We extended those observations here, characterizing M. pneumoniae infection of NHBE for up to 4 weeks. Colonisation of the apical surface was followed by pericellular invasion of the basolateral compartment and migration across the underlying transwell membrane. Despite fluctuations in transepithelial electrical resistance and increased NHBE cell desquamation, barrier function remained largely intact. Desquamation was accompanied by epithelial remodelling that included cytoskeletal reorganisation and development of deep furrows in the epithelium. Finally, M. pneumoniae strains S1 and M129 differed with respect to invasion and histopathology, consistent with contrasting virulence in experimentally infected mice. In summary, this study reports pericellular invasion, NHBE cytoskeletal reorganisation, and tissue remodelling with persistent infection in a human airway epithelium model, providing clear insight into the likely route for extrapulmonary spread.