A severe Mycoplasma pneumoniae pneumonia inducing an acute antibody-mediated pulmonary graft rejection

Correlation of DNA load, genotyping, and clinical phenotype of Mycoplasma pneumoniae infection in children

Introduction

This study aimed to investigate the correlation between Mycoplasma pneumoniae (MP)-DNA load in the bronchoalveolar lavage fluid (BALF) of children with MP pneumonia (MPP) and its subtypes, relevant laboratory data, imaging, extrapulmonary complications in infected children, and its clinical significance in evaluating the disease.

Methods

Children hospitalized with MPP at Tianjin Children's Hospital between December 2017 and December 2020 were selected for the study, excluding those with mixed viral, bacterial, and fungal infections. Children were divided into low- and high-load groups according to the MP DNA load in BALF using real-time quantitative fluorescence polymerase chain reaction (PCR). After a successful MP culture, positive specimens were subjected to PCR-Restriction fragment length polymorphism and Multiple-locus variable number tandem repeat analysis typing. Basic data, clinical information, laboratory data, and radiological results were collected from all children included in the study.

Results

The PI-I type dominated the different load groups. Children in the low-load group had more wheezing and shortness of breath; however, children in the high-load group had a higher length of hospitalization, maximum fever temperature, higher chills/chilliness, incidence of abdominal pain, and higher C-reactive protein (CRP), procalcitonin (PCT) and aspartate aminotransferase (AST) levels. Children in the high-load group were more likely to have imaging changes such as pleural effusion, and the incidence of respiratory infections and extrapulmonary complications was higher than that of those in the low-load group. We applied Spearman's correlation analysis to clarify the relationship between MP DNA load and the clinical severity of MPP. We found that MP DNA load was positively correlated with length of hospitalization, maximum fever temperature, CRP, PCT, Interleukin-6 (IL-6), and AST levels, and negatively correlated with fever and cough durations, white blood cell count (WBC), and proportion of monocytes (MONO). The degree of correlation was as follows: length of hospitalization > IL-6 > cough duration > AST > fever duration > PCT > WBC > proportion of MONO > maximum fever temperature > CRP levels.

Conclusions

MP DNA load was not correlated with MP typing but was significantly correlated with the children's clinical phenotype. Therefore, the MP DNA load helps in the early diagnosis of infection and can better predict disease regression.

Immunosuppressive Treatment and Its Effect on the Occurrence of Pneumocystis jiroveci, Mycoplasma pneumoniae, Chlamydophila pnemoniae, and Legionella pneumophila Infections/Colonizations Among Lung Transplant Recipients

BACKGROUND

The aim of the study was to assess the frequency of infections caused by Pneumocystis jiroveci, Chlamydophila pneumoniae, Legionella pneumophila, and Mycoplasma pneumoniae among lung transplant recipients in the context of immunosuppression.

METHODS

The study group consisted of 94 patients (37 women and 57 men; mean age 42.03 years) transplanted between 2009 and 2016 at the Silesia Center for Heart Diseases (SCCS). Immunosuppressive treatment (induction and maintenance therapy) was assessed. The immunofluorescence methods were used to detect the P. jiroveci, L. pneumophila, C. pneumoniae, and M. pneumoniae antigens in samples obtained from the respiratory tract.

RESULTS

Thirty-two of 94 graft recipients developed atypical or opportunistic infection. The median time of its occurrence was 178 days after transplantation. P. jiroveci was responsible for 84.38% of first infections. Five patients developed infection with P. jiroveci and C. pneumoniae. None of the infections occurred during induction of immunosuppression. An opportunistic or atypical infection developed in 19.35% of the patients treated with a tacrolimus-based regimen, and in 43.33% of patients on a cyclosporine-based regimen.

CONCLUSION

Infection with P. jiroveci is a recognized problem after lung transplantation and should be monitored. The percentage of infected patients is higher in patients treated with a cyclosporine-based regimen in comparison to those treated with tacrolimus.