Clinical significance of different bacterial load of Mycoplasma pneumoniae in patients with Mycoplasma pneumoniae pneumonia

Mycoplasma hominis Causes DNA Damage and Cell Death in Primary Human Keratinocytes

Mycoplasma hominis can be isolated from the human urogenital tract. However, its interaction with the host remains poorly understood. In this study, we aimed to assess the effects of M. hominis infection on primary human keratinocytes (PHKs). Cells were quantified at different phases of the cell cycle. Proteins involved in cell cycle regulation and apoptosis progression were evaluated. The expression of genes encoding proteins that are associated with the DNA damage response and Toll-like receptor pathways was evaluated, and the cytokines involved in inflammatory responses were quantified. A greater number of keratinocytes were observed in the Sub-G0/G1 phase after infection with M. hominis. In the viable keratinocytes, infection resulted in G2/M-phase arrest; GADD45A expression was increased, as was the expression of proteins such as p53, p27, and p21 and others involved in apoptosis regulation and oxidative stress. In infected PHKs, the expression of genes associated with the Toll-like receptor pathways showed a change, and the production of IFN-γ, interleukin (IL) 1β, IL-18, IL-6, and tumour necrosis factor alpha increased. The infection of PHKs by M. hominis causes cellular damage that can affect the cell cycle by activating the response pathways to cellular damage, oxidative stress, and Toll-like receptors. Overall, this response culminated in the reduction of cell proliferation/viability in vitro.

Combination of in vivo phage therapy data with in silico model highlights key parameters for pneumonia treatment efficacy

The clinical (re)development of bacteriophage (phage) therapy to treat antibiotic-resistant infections faces the challenge of understanding the dynamics of phage-bacteria interactions in the in vivo context. Here, we develop a general strategy coupling in vitro and in vivo experiments with a mathematical model to characterize the interplay between phage and bacteria during pneumonia induced by a pathogenic strain of Escherichia coli. The model allows the estimation of several key parameters for phage therapeutic efficacy. In particular, it quantifies the impact of dose and route of phage administration as well as the synergism of phage and the innate immune response on bacterial clearance. Simulations predict a limited impact of the intrinsic phage characteristics in agreement with the current semi-empirical choices of phages for compassionate treatments. Model-based approaches will foster the deployment of future phage-therapy clinical trials.

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.

The diagnostic value of serological tests and real-time polymerase chain reaction in children with acute Mycoplasma pneumoniae infection

Background

This study set out to evaluate the clinical significance and diagnostic effectiveness of serological tests and real-time polymerase chain reactions (RT-PCR) in children of different age groups and disease durations infected with Mycoplasma pneumoniae (MP).

Methods

Pediatric patients with lower respiratory tract infection (LRTI) confirmed by polymerase chain reaction (PCR) were enrolled and subjected to bronchoalveolar lavage fluid PCR (BALF-PCR) for MP infection. The diagnostic values of the serum immunoglobulin M (IgM) test, paired sera immunoglobulin G (IgG) test, RT PCR applied to nasopharyngeal aspirates (NPA-PCR), and combined IgM and NPA-PCR test were evaluated.

Results

When BALF PCR was used as the gold standard, the MP positivity rate of combined IgM and NPA PCR was 78.85%in children aged 3–5 years. The positivity rates of IgM, NPA PCR, and combined IgM and NPA PCR in children older than 5 years were 71.21%, 72.72%, and 84.85%, respectively. The detection rate of combined IgM and NPA PCR was consistent with BALF PCR (Kappa =0.727). The MP positivity rates of combined IgM and NPA PCR at 1–2 weeks was as high as 91.11%, and was consistent with the BALF PCR (Kappa =0.756). Moreover, the positivity rates of IgM or NPA PCR at 2-3 weeks were 63.16%, and were consistent with each other (Kappa =0.771).

Conclusions

Combined IgM and NPA PCR is the optimal test to confirm MP infection among children aged 3–5 years in cases with a disease duration of less than2 weeks, and either NPA PCR or IgM is recommended for children older than 5 years with a disease duration of 2–3 weeks.

Keywords

Mycoplasma pneumoniae pneumonia (MPP); diagnosis; children; age; disease duration

Clinical Analysis of 122 Cases with Mycoplasma Pneumonia Complicated with Atelectasis: A Retrospective Study

INTRODUCTION

This study aims to explore the clinical characteristics, treatment, and prognosis of mycoplasma pneumonia complicated with atelectasis.

METHODS

A retrospective analysis was performed on 122 children with mycoplasma pneumonia complicated with atelectasis. These children were hospitalized in the Xiamen Campus of the Pediatric Hospital of Fudan University and the Children's Hospital of Xiamen between December 2015 and December 2018. A diagnosis was made for each case on the basis of the clinical symptoms and signs, Mycoplasma pneumoniae-specific IgM antibody, and imaging results.

RESULTS

Among the 122 cases with mycoplasma pneumonia complicated with atelectasis, all cases had retractable M. pneumoniae infection, 102 cases underwent fibrobronchoscopic lavage treatment, and all cases were treated with macrolide antibiotics after a definite diagnosis was made. Furthermore, 107 cases improved and were discharged. Follow-up was performed for 3-4 weeks for all patients, and all patients, including the five cases with retractable disease, recovered well.

CONCLUSION

The major clinical manifestations for M. pneumoniae pneumonia are fever and stimulatory dry cough. Macrolide antibiotics remain the treatment of choice.

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.

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.

Multi-center evaluation of one commercial and 12 in-house real-time PCR assays for detection of Mycoplasma pneumoniae

Detection of Mycoplasma pneumoniae by real-time PCR is not yet standardized across laboratories. We have implemented a standardization protocol to compare the performance of thirteen commercial and in-house approaches. Despite differences on threshold values of samples, all assays were able to detect at least 20M. pneumoniae genomes per reaction.

[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.

[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.

Kawasaki disease associated with Mycoplasma pneumoniae

BACKGROUND

Kawasaki disease (KD) is an illness of unknown etiology that mostly occurs in children under 5 years of age and is the leading cause of acquired heart disease all over the world. Mycoplasma pneumoniae (MP) was one of the likely causative agents of KD. However, the etiologic effect of MP in KD has not been fully recognized.

METHODS

We prospectively analyzed the clinical records of 450 patients with KD hospitalized in Children's Hospital of Soochow University from 2012 to 2014. Using medical records, we retrospectively identified patients with low respiratory tract infection (non-KD group).

RESULTS

Of the 450 KD patients, MP was positive in 62 (13.8 %). The median age of the MP + KD+ group was significantly older than the MP-KD+ group (25 vs 14.5 months, P < 0.01). MP + KD+ group had higher levels of ESR, N% and CRP than the MP-KD+ group. MP + KD+ group were more frequent in respiratory disorders than MP-KD+ group with a P < 0.05. No statistical difference of non-responders or coronary artery lesion was found between the groups.

CONCLUSIONS

MP infections are found in an important proportion of the KD patients (13.8 % in our series). MP infection tended to occur in older populations and with a higher rate of respiratory tract involvement in patients with KD. No statistical difference of non-responders or coronary artery lesion was found between the MP+ and MP- KD patients.

Mycoplasma pneumoniae: Current Knowledge on Nucleic Acid Amplification Techniques and Serological Diagnostics

Mycoplasma pneumoniae (M. pneumoniae) belongs to the class Mollicutes and has been recognized as a common cause of respiratory tract infections (RTIs), including community-acquired pneumonia (CAP), that occur worldwide and in all age groups. In addition, M. pneumoniae can simultaneously or sequentially lead to damage in the nervous system and has been associated with a wide variety of other acute and chronic diseases. During the past 10 years, the proportion of LRTI in children and adults, associated with M. pneumoniae infection has ranged from 0 to more than 50%. This variation is due to the age and the geographic location of the population examined but also due to the diagnostic methods used. The true role of M. pneumoniae in RTIs remains a challenge given the many limitations and lack of standardization of the applied diagnostic tool in most cases, with resultant wide variations in data from different studies. Correct and rapid diagnosis and/or management of M. pneumoniae infections is, however, critical to initiate appropriate antibiotic treatment and is nowadays usually done by PCR and/or serology. Several recent reviews, have summarized current methods for the detection and identification of M. pneumoniae. This review will therefore provide a look at the general principles, advantages, diagnostic value, and limitations of the most currently used detection techniques for the etiological diagnosis of a M. pneumoniae infection as they evolve from research to daily practice.

Evaluation of five real-time PCR assays for detection of Mycoplasma pneumoniae

Four commercial real-time PCR assays to detect Mycoplasma pneumoniae were tested, and the results were compared with the results for an in-house approach. Despite differences of crossing threshold values of up to 4, assays were able to detect at least 20 CFU/5 μl (52 fg DNA/5 μl) of sample with the Diagenode kit showing the best clinical sensitivity.