Chlamydia pneumoniae and Mycoplasma pneumoniae in children with cystic fibrosis: impact on bacterial respiratory microbiota diversity

What diagnostic tests are available for respiratory infections or pulmonary exacerbations in cystic fibrosis: A scoping literature review

A scoping review methodological framework formed the basis of this review. A search of two electronic databases captured relevant literature published from 2013. 1184 articles were screened, 200 of which met inclusion criteria. Included studies were categorised as tests for either respiratory infections OR pulmonary exacerbations. Data were extracted to ascertain test type, sample type, and indication of use for each test type. For infection, culture is the most common testing method, particularly for bacterial infections, whereas PCR is utilised more for the diagnosis of viral infections. Spirometry tests, indicating lung function, facilitate respiratory infection diagnoses. There is no clear definition of what an exacerbation is in persons with CF. A clinical checklist with risk criteria can determine if a patient is experiencing an exacerbation event, however the diagnosis is clinician-led and will vary between individuals. Fuchs criteria are one of the most frequently used tests to assess signs and symptoms of exacerbation in persons with CF. This scoping review highlights the development of home monitoring tests to facilitate earlier and easier diagnoses, and the identification of novel biomarkers for indication of infections/exacerbations as areas of current research and development. Research is particularly prevalent regarding exhaled breath condensate and volatile organic compounds as an alternative sampling/biomarker respectively for infection diagnosis. Whilst there are a wide range of tests available for diagnosing respiratory infections and/or exacerbations, these are typically used clinically in combination to ensure a rapid, accurate diagnosis which will ultimately benefit both the patient and clinician.

Chlamydia pneumoniae Upsurge at Tertiary Hospital, Lausanne, Switzerland

Chlamydia pneumoniae infection cases have usually accounted for <1.5% of community-acquired respiratory tract infections. Currently, Lausanne, Switzerland is experiencing a notable upsurge in cases, with 28 reported within a span of a few months. This upsurge in cases highlights the need for heightened awareness among clinicians.

Research status and challenges of Mycoplasma pneumoniae pneumonia in children: A bibliometric and visualization analysis from 2011 to 2023

BACKGROUND

Mycoplasma pneumoniae (MP) infections occur in regional outbreaks every 3 to 7 years, lasting up to 2 years. Since this fall, there has been a significant rise in MP infections among children in China, indicating a regional epidemiological trend that imposes an increased national public health burden. To date, bibliometric methods have not been applied to studies on MP infection in children.

METHODS

We searched for all relevant English publications on MP pneumonia in children published from 2011 to 2023 using Web of Science. Analytical software tools such as Citespace and VOSviewer were employed to analyze the collected literature.

RESULTS

993 articles on MP pneumonia in children were published in 338 academic journals by 5062 authors affiliated with 1381 institutions across 75 countries/regions. China led in global productivity with 56.19%. Among the top 10 prolific organizations, 8 were Chinese institutions, with Soochow University being the most active, followed by Capital Medical University and Zhejiang University. Zhimin Chen from Zhejiang University School of Medicine exhibited the highest H-index of 32. Keyword co-occurrence network analysis revealed 7 highly relevant clusters.

CONCLUSION

The current research hotspots and frontiers in this field are primarily MP pneumonia, refractory MP pneumonia, lactate dehydrogenase, asthma, and biomarker. We anticipate that this work will provide novel insights for advancing scientific exploration and the clinical application of MP pneumonia in children.

miRNA, lncRNA and circRNA: targeted molecules with therapeutic promises in Mycoplasma pneumoniae infection

Mycoplasma pneumoniae (MP) is primarily recognized as a respiratory pathogen that causes community-acquired pneumonia, which can lead to acute upper and lower airway inflammation and extrapulmonary syndrome. Refractory pneumonia caused by MP can cause severe complications and even be life-threatening, particularly in infants and the elderly. It is well-known that non-coding RNAs (ncRNAs) represented by miRNAs, lncRNAs and circRNAs have been manifested to be widely involved in the regulation of gene expression. Growing evidence indicates that these ncRNAs have distinct differentiated expression in MP infection and affect multiple biological processes, playing an indispensable role in the initiation and promotion of MP infection. However, the epigenetic mechanisms involved in the development of MP infection remain unclear. This article reviews the mechanisms by which miRNAs, lncRNAs, and circRNAs mediate MP infection, such as inflammatory responses, apoptosis and pulmonary fibrosis. Focusing on miRNAs, lncRNAs and circRNAs associated with MP infection could provide new insights into this disease's early diagnosis and therapeutic approaches.

Reserve of Wnt/β-catenin Signaling Alleviates Mycoplasma pneumoniae P1-C-induced Inflammation in airway epithelial cells and lungs of mice

Mycoplasma pneumoniae (M. pneumoniae) is the most common pathogen of respiratory tract infections in both children and adults. M. pneumoniae P1 adhesin plays an important role in the pathogenesis of M. pneumoniae infection by mediating the attachment of pathogen to host cells. The inoculation of C-terminal residuals of P1 (P1-C) showed a protective role from M. pneumoniae infection. Accumulated evidence suggests that the Wnt/β-Catenin signaling is implicated in regulation of inflammatory responses to bacterial infections. However, mechanisms underlying the regulatory roles of Wnt signaling in host cells in response to M. pneumoniae infections are incompletely understood. In the present study, the impact and molecular mechanism of Wnt/β-catenin signaling in immune responses induced by M. pneumoniae P1-C were investigated. The results demonstrated that the P1-C could activate Wnt/β-catenin and Toll-like receptor (TLR) signaling in primary mouse airway epithelial cells cultured in an air-liquid interface (ALI) state. Interestingly, the inhibition of Wnt/β-catenin signaling by an adenovirus-mediated Wnt inhibitor Dickkopf-1 (Dkk1) gene transduction alleviated the P1-C induced inflammation fibrosis in mouse lung, accompanied by the reduced expression of epithelial mesenchymal transition (EMT) markers. Mechanistical analysis further demonstrated that the Dkk1 could suppress the expression of JAK2/STAT1-STAT3 and Caspase3, 8/Bax signaling in mouse lung tissues. In vitro study further revealed that XAV939, a small molecule of Wnt/β-catenin inhibitor, inhibited the P1-C-activated TLR4/MyD88 signaling and cytokine productions in primary mouse airway ALI epithelial cells. This study thus provides an insight into the function of Wnt/β-catenin signaling in regulation of the pathogenesis of M. pneumoniae infection, suggesting that targeting Wnt/β-catenin signaling by gene transduction of Dkk1, or pharmacological molecules of inhibitor may be a promised approach that worthy of further investigation in the treatment of M. pneumoniae pneumonia.

DNA extraction leads to bias in bacterial quantification by qPCR

Quantitative PCR (qPCR) has become a widely used technique for bacterial quantification. The affordability, ease of experimental design, reproducibility, and robustness of qPCR experiments contribute to its success. The establishment of guidelines for minimum information for publication of qPCR experiments, now more than 10 years ago, aimed to mitigate the publication of contradictory data. Unfortunately, there are still a significant number of recent research articles that do not consider the main pitfalls of qPCR for quantification of biological samples, which undoubtedly leads to biased experimental conclusions. qPCR experiments have two main issues that need to be properly tackled: those related to the extraction and purification of genomic DNA and those related to the thermal amplification process. This mini-review provides an updated literature survey that critically analyzes the following key aspects of bacterial quantification by qPCR: (i) the normalization of qPCR results by using exogenous controls, (ii) the construction of adequate calibration curves, and (iii) the determination of qPCR reaction efficiency. It is primarily focused on original papers published last year, where qPCR was applied to quantify bacterial species in different types of biological samples, including multi-species biofilms, human fluids, and water and soil samples. KEY POINTS: • qPCR is a widely used technique used for absolute bacterial quantification. • Recently published papers lack proper qPCR methodologies. • Not including proper qPCR controls significantly affect experimental conclusions.