[show abstract][hide abstract] ABSTRACT: Mycoplasma pneumoniae (M. pneumoniae) is one of the major etiological agents for community-acquired pneumonia (CAP) in all age groups. The early host response to M. pneumoniae infection relies on the concerted release of proteins with various biological activities. However, no comprehensive analysis of the secretory proteins has been conducted to date regarding the host response upon M. pneumoniae infection.
We employed the liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based label-free quantitative proteomic technology to identify and characterize the members of the human alveolar epithelial carcinoma A549 cell secretome during M. pneumoniae infection. A total of 256 proteins were identified, with 113 being differentially expressed (>1.5-fold change), among which 9 were only expressed in control cells, 10 only in M. pneumoniae-treated cells, while 55 were up-regulated and 39 down-regulated by M. pneumoniae. The changed expression of some of the identified proteins was validated by RT-PCR and immunoblot analysis. Cellular localization analysis of the secretome data revealed 59.38% of the proteins were considered as "putative secretory proteins". Functional analysis revealed that the proteins affected upon M. pneumoniae infection were mainly related to metabolic process, stress response, and immune response. We further examined the level of one up-regulated protein, IL-33, in clinical samples. The result showed that IL-33 levels were significantly higher in the plasma and bronchoalveolar lavage fluid (BALF) of M. pneumoniae pneumonia (MPP) patients.
The present study provided systematic information about the changes in the expression of secretory proteins during M. pneumoniae infection, which is useful for the discovery of specific biomarkers and targets for pharmacological intervention.
[show abstract][hide abstract] ABSTRACT: Inflammatory mediators (i.e. cytokines) play a pivotal role in the regulation of pathophysiological processes during EV71-induced hand, foot and mouth disease (HFMD). Different T cell subsets have distinct cytokine secretion profiles, and alteration in the T cell subsets frequency (imbalance) during infection leads to changed cytokine patterns. However, the effects of EV71 infection on T cell subsets were not clear. The objective of this study was to determine whether EV71-induced HFMD can be explained by the emergence of particular T-cell subsets (Th1, Th2, Tc1, Tc2, Th17, Tc17 and Treg cells) and the cytokine they produced (IFN-γ, IL-4, IL-17A and TGF-β1), as well as distinct responses to EV71 infection. We found that when compared to the control group, the percentage of Th1 and Tc1 cells was significantly higher in mild and severe HFMD group. Similar results were found in the Th1/Th2 ratio and IFN-γ levels. On the other hand, the percentage of Th17 cells and IL-17A levels were the highest in severe HFMD cases, and lowest in controls. Similar trend was also found for the Th17/Treg cell ratio. An optimal cutoff value of 2.15% for Th17 cell and 6.72pg/ml for IL-17A provided a discriminatory value for differentiating the severity of HFMD cases by receiver operating characteristic curve analyses. These findings reveal that the Th1/Th2 and Th17/Treg imbalance exist in HFMD patients, suggesting their involvement in the pathogenesis of EV71 infection, which may have potential value as biomarkers.
[show abstract][hide abstract] ABSTRACT: Objectives:To understand the situation of macrolide-resistant genotypes of Mycoplasma pneumoniae (MP), and analyze the relationship between macrolide-resistant genotypes and clinical manifestations of Mycoplasma pneumoniae pneumonia (MPP).Methods:Full-length sequencing of the 23S rRNA gene of MP was performed in 235 nasopharyngeal aspirates (NPAs) from children with MPP. We also retrospectively compared the clinical characteristics of macrolide-resistant (MR) MP infections and macrolide-sensitive (MS) MP infections.Results:A total of 206 patients had point mutations in the 23S rRNA gene of MP, and they were defined as MR patients. The remaining 29 patients without point mutations were defined as MS patients. Among 206 MR patients, 199 (96.6%) had A2063G mutations, 6 with A2063T mutations, and the remaining one with an A2064G mutation. Concerning clinical manifestations, we found the median fever duration was 8 (range 0∼42) days and 6 (0∼14) days (P<0.01), the median hospitalization duration was 8 (2∼45) days and 6 (3∼16) days (P<0.01), and the median fever duration after macrolide therapy was 5 (0∼42) days and 3 (0∼10) days (P<0.01), respectively in the MR and MS group. We also found the incidence of extra-pulmonary complications in the MR group was significantly higher than that in the MS group (P<0.05). And radiological findings were more serious in the MR group than those in the MS group (P<0.05).Conclusions:The increasing prevalence of MR MP has become a significant clinical issue in the pediatric patients, which may lead to more extra-pulmonary complications, and severe clinical features and radiological manifestations.
Antimicrobial Agents and Chemotherapy 11/2013; · 4.57 Impact Factor
[show abstract][hide abstract] ABSTRACT: Lymphatic malformations are vascular malformations and consist of masses of abnormal lymphatic channels. They are uncommon in the mediastinum. We report three cases of giant mediastinum lymphatic malformations in children. One case developed two episodes of cardiopulmonary arrests, and the other two were first diagnosed and treated as pneumonia. They all recovered well after surgery. The diagnosis is rather important in lymphatic malformations. A delay in diagnosis of mediastinum lymphatic malformation increases the risk of death and prolonged clinical course. Thus, mediastinum lymphatic malformations should be kept in mind as a differential diagnosis of pneumonia and mass in the neck.
[show abstract][hide abstract] ABSTRACT: Tracheal diverticulum is a paratracheal air cyst in connection with the trachea. It may be congenital or acquired. Congenital tracheal diverticula in infants are rare. Imaging techniques such as high-resolution computed tomography and three-dimensional reconstruction of the airway are useful for diagnosis. Here we report three cases with congenital tracheal diverticula, which were diagnosed by imaging techniques.
[show abstract][hide abstract] ABSTRACT: How to diagnose Mycoplasma pneumoniae etiology in a child with pneumonia? Xu et al. compared the detection rates of M. pneumoniae in nasopharyngeal aspirates (NPA) vs. bronchoalveolar lavage (BAL) obtained from 406 children hospitalized pneumonia (3). Serum samples were tested for microbe- specific IgM and BAL samples for microbe-specific DNA by quantitative polymerase chain reaction (PCR). NPA samples were studied by the same PCR in 357 (88%) cases. IgM determination was positive in 101 (24.9%) patients, regarded as mycoplasmal infections and "gold standards" when evaluating the diagnostic value of NPA vs. BAL samples. The positivity rate of PCR was 48.5% in BAL and 40.9% in NPA. The sensitivity and specificity of PCR was 78.6% and 63.5% in NPA and 70.3% and 58.7% in BAL, respectively. The authors conclude that NPA is superior to BAL for diagnosing mycoplasmal pneumonia (3). However, there was nearly a total overlapping in the 95% confidence intervals (CI) of sensitivities and specificities of PCR in NPA vs. BAL. There were some differences in receiver operating characteristic curves, but no comparable param- eters like likelihood ratios (LR) or areas under curve were presented. LRs (but not 95% CIs) can be calculated from the presented figures, and LR+ was 2.15 for PCR in NPA and 1.70 in BAL, which means only minor effects on pre- test probability. The study was retrospective and the material was selected (bronchoscopy needed). The positivity rate in NPA samples was much lower, 16.9%, in all 7,381 pneumonia children treated in the hospital during the study period (3). In population-based serological studies including both inpatients and outpatients, M. pneumoniae has caused 14.3-18.4% of pneumonia cases in 5-year- old children (1, 2). Since the positivity rates are dependent on age and setting, the analyses should be age specific, and LR+ and LR- should be used instead of predictive values. In addition,the results are dependenton the"gold standards"used.
European Journal of Pediatrics 10/2011; 171(3):595-6. · 1.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: Mycoplasma pneumoniae (M. pneumoniae) is an important community-acquired pneumonia pathogen. Serological test and polymerase chain reaction (PCR) assay are the two main laboratory tests to detect M. pneumoniae now. Little information was compared about the sensitivity and specificity of PCR using different specimens including bronchoalveolar lavage (BAL) and nasopharyngeal aspirate (NPA). The aim of the present study was to evaluate diagnostic values of different specimens by fluorescence quantitative real-time PCR and to find clinical features helpful to diagnose M. pneumoniae pneumonia (MPP). Four hundred and six hospitalized pneumonia children were studied. M. pneumoniae DNA in NPA and BAL samples were detected by fluorescence quantitative real-time PCR. M. pneumoniae-specific IgM was tested by ELISA. MPP were diagnosed based on positive M. pneumoniae-specific IgM in 101 (24.9%) children. The median ages of MPP and non-MPP children were 4.1 and 2.4 years, respectively, with significant difference between them (p < 0.001). Laboratory results including leukocyte count, neutrophil percentage, immunoglobulins, except serum IgM, subgroups of T lymphocyte, and BAL cell count had no significant differences in MPP and non-MPP. BAL macrophage cell percentage was lower in BAL-PCR positive children (p = 0.003), while BAL neutrophil percentage was higher in BAL-PCR positive children (p = 0.007). PCR from NPA and BAL were similar in diagnostic parameters, including sensitivity, specificity, PPV, and NPV (78.6%, 63.4%, 39.8%, and 90.6% for NPA-PCR, respectively; 70.3%, 58.7%, 36.0%, and 85.6% for BAL-PCR, respectively). CONCLUSIONS: NPA is better than BAL as PCR sample in MPP diagnosis for similar performance in PCR assay, cheap, and less invasive. BAL is useful in defining local inflammatory condition. Age is the only prefigurative factor in MPP.
European Journal of Pediatrics 11/2010; 170(7):851-8. · 1.91 Impact Factor
[show abstract][hide abstract] ABSTRACT: The role of sphingolipids in bacterial pathogenesis has been gradually recognized. In an effort to identify the possible involvement of sphingolipids during Mycoplasma pneumoniae (M. pneumoniae) infection, we first adopted a lipidomic approach to achieve the profiles of major sphingolipid species of M. pneumoniae as well as human lung carcinoma A549 cells, and further evaluated the effects of M. pneumoniae infection on sphingolipid metabolism in A549 cells. It was shown that M. pneumoniae and A549 cells share many common sphingolipid species, however, M. pneumoniae possesses certain specific molecular species that are not found in A549 cells. On the other hand, M. pneumoniae infection could alter sphingolipid metabolism in A549 cell, including the generation of new ceramide and sphingomyelin species, or the increase/decrease of intensities, which varies depending on the different infection doses and times. The effects of M. pneumoniae infection on two key enzymes in sphingolipid metabolism, serine palmitoyltransferase (SPT) and acid sphingomyelinase (ASM), were also examined. It was found that M. pneumoniae infection could affect the expression of SPT or the distribution of ASM at certain concentrations. These data suggest that M. pneumoniae infection could influence sphingolipid metabolism of its host, which might be related to its pathogenicity.
[show abstract][hide abstract] ABSTRACT: Mycoplasma pneumoniae is a frequent cause of community-acquired bacterial respiratory infections in children and adults. In the present study, using a proteomic approach, we studied the effects of M. pneumoniae infection on the protein expression profile of A549 human lung carcinoma cells. M. pneumoniae infection induced changes in the expression of cellular proteins, in particular a group of proteins involved in the oxidative stress response, such as glucose-6-phosphate 1-dehydrogenase, NADH dehydrogenase (ubiquinone) Fe-S protein 2, and ubiquinol-cytochrome c reductase complex core protein I mitochondrial precursor. The oxidative status of M. pneumoniae-infected cells was evaluated, and the results revealed that M. pneumoniae infection indeed caused generation of reactive oxygen species (ROS). It was further shown that M. pneumoniae infection also induced DNA double-strand breaks, as demonstrated by the formation of gammaH2AX foci. On the other hand, an ROS scavenger, N-acetylcysteine, could inhibit the ROS generation, as well as decrease gammaH2AX focus formation. This is the first report showing that M. pneumoniae infection can directly induce DNA damage, at least partially, through the generation of ROS, and thus this report strengthens the powerful application of proteomics in the study of the pathogenesis of M. pneumoniae.
Infection and immunity 08/2008; 76(10):4405-13. · 4.21 Impact Factor