Mycoplasma pneumoniae and its role as a human pathogen

Macrolide-Resistant Mycoplasma pneumoniae Infections in Children, Ohio, USA

Emergence of macrolide-resistant Mycoplasma pneumoniae (MRMp) challenges empiric macrolide therapy. Our goal was to determine MRMp rates and define characteristics of children infected with macrolide-sensitive M. pneumoniae (MSMp) versus MRMp in Ohio, USA. We cultured PCR-positive M. pneumoniae specimens and sequenced M. pneumoniae-positive cultures to detect macrolide resistance mutations. We reviewed medical records to compare characteristics of both groups. We identified 14 (2.8%) MRMp and 485 (97.2%) MSMp samples. Patients in these groups had similar demographics and clinical characteristics, but patients with MRMp had longer hospitalizations, were more likely to have received previous macrolides, and were more likely to have switched to alternative antimicrobial drugs. MRMp-infected patients also had ≈5-fold greater odds of pediatric intensive care unit admission. Rates of MRMp infections in children in central Ohio are low, but clinicians should remain aware of the risk for severe illness caused by these pathogens.

In vitro activities of acetylmidecamycin and other antimicrobials against human macrolide-resistant Mycoplasma pneumoniae isolates

OBJECTIVES

To assess the in vitro activities of acetylmidecamycin, a 16-membered macrolide, and 11 other antimicrobial agents against human mycoplasmas.

METHODS

A total of 187 clinical isolates, Mycoplasma pneumoniae (n = 110), Mycoplasma hominis (n = 26) and Ureaplasma species (n = 51), were included in this study. The MICs of 12 antimicrobial agents, including acetylmidecamycin, thiamphenicol, chloramphenicol and some other macrolides, fluoroquinolones and tetracyclines, for these clinical isolates were determined by the broth microdilution method.

RESULTS

For M. pneumoniae, the MIC90 values of the tested macrolides were: acetylmidecamycin (1 mg/L)<josamycin (4 mg/L)<midecamycin (8 mg/L)<azithromycin (16 mg/L)<erythromycin (>128 mg/L). Thiamphenicol and chloramphenicol had the same MIC90 (2 mg/L). For Ureaplasma species, the MIC90 values were: acetylmidecamycin (0.25 mg/L)<josamycin (0.5 mg/L)=midecamycin<azithromycin (1 mg/L)=erythromycin. Chloramphenicol had a lower MIC90 (2 mg/L) than that of thiamphenicol (4 mg/L). For M. hominis, the MIC90 values were: acetylmidecamycin (0.25 mg/L)<josamycin (0.5 mg/L)<midecamycin (2 mg/L)<azithromycin (>128 mg/L)=erythromycin. The MIC90 values of chloramphenicol and thiamphenicol were 2 and 4 mg/L, respectively.

CONCLUSIONS

The results indicated that acetylmidecamycin and thiamphenicol are active in vitro against the most common mycoplasma species infecting humans, including those resistant to macrolides and fluoroquinolones. Acetylmidecamycin and thiamphenicol might be a promising option for clinicians to treat infections caused by Mycoplasma and Ureaplasma spp., particularly macrolide-resistant M. pneumoniae in paediatrics and fluoroquinolone-resistant M. hominis in adults. Further investigation of their clinical roles in treating infections caused by these organisms is warranted.

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.

Mycoplasma pneumoniae Genotypes and Clinical Outcome in Children

Factors leading to the wide range of manifestations associated with Mycoplasma pneumoniae infection are unclear. We investigated whether M. pneumoniae genotypes are associated with specific clinical outcomes. We compared M. pneumoniae loads and genotypes of children with mucocutaneous disease to those of children with pneumonia, family members with upper respiratory tract infection (URTI), and carriers from a prospective cohort study (n = 47; 2016 to 2017) and to those of other children with mucocutaneous disease from a case series (n = 7; 2017 to 2020). Genotyping was performed using macrolide resistance determination, P1 subtyping, multilocus variable-number tandem-repeat analysis (MLVA), and multilocus sequence typing (MLST). Comparisons were performed with a pairwise Wilcoxon rank sum test and a Fisher exact test with corrections for multiple testing, as appropriate. M. pneumoniae loads did not statistically differ between patients with mucocutaneous disease and those with pneumonia or carriers. Macrolide resistance was detected in 1 (1.9%) patient with mucocutaneous disease. MLVA types from 2016 to 2017 included 3-5-6-2 (n = 21 [46.7%]), 3-6-6-2 (n = 2 [4.4%]), 4-5-7-2 (n = 14 [31.1%]), and 4-5-7-3 (n = 8 [17.8%]), and they correlated with P1 subtypes and MLST types. MLVA types were not associated with specific outcomes such as mucocutaneous disease, pneumonia, URTI, or carriage. They were almost identical within families but varied over geographic location. MLVA types in patients with mucocutaneous disease differed between 2016 to 2017 (3-5-6-2, n = 5 [62.5%]) and 2017 to 2020 (4-5-7-2, n = 5 [71.4%]) (P = 0.02). Our results suggest that M. pneumoniae genotypes may not determine specific clinical outcomes.

Clinical Evaluation of a Novel Point-of-Care Assay To Detect Mycoplasma pneumoniae and Associated Macrolide-Resistant Mutations

The recent increase in macrolide-resistant Mycoplasma pneumoniae in Asia has become a continuing problem. A point-of-care testing method that can quickly detect M. pneumoniae and macrolide-resistant mutations (MR mutations) is critical for proper antimicrobial use. Smart Gene (Mizuho Medy Co., Ltd., Tosu City, Saga, Japan) is a compact and inexpensive fully automatic gene analyzer that combines amplification with PCR and the quenching probe method to specify the gene and MR mutations simultaneously. We performed a clinical evaluation of this device and its reagents on pediatric patients with suspected M. pneumoniae respiratory infections and evaluated the impact of the assay on antimicrobial selection. Using real-time PCR as a comparison control, the sensitivity of Smart Gene was 97.8% (44/45), its specificity was 93.3% (98/105), and its overall concordance rate was 94.7% (142/150). The overall concordance rate of Smart Gene diagnosis of MR mutations in comparison with sequence analysis was 100% (48/48). The ratio of MR mutations was significantly higher at high-level medical institutions than at a primary medical clinic (P = 0.023), and changes in antibiotic therapy to drugs other than macrolides were significantly more common in patients with MR mutations (P = 0.00024). Smart Gene demonstrated excellent utility in the diagnosis of M. pneumoniae and the selection of appropriate antimicrobials for MR mutations at primary medical institutions, which play a central role in community-acquired pneumonia care. The use of this device may reduce referrals to high-level medical institutions for respiratory infections, thereby reducing the medical and economic burdens on patients.

Mutations in domain V of Mycoplasma pneumoniae 23S rRNA and clinical characteristics of pediatric M. pneumoniae pneumonia in Nanjing, China

OBJECTIVE

To investigate the prevalence of mutations in domain V of Mycoplasma pneumoniae (MP) 23S ribosomal RNA (rRNA) and the clinical characteristics of pediatric MP pneumonia (MPP) in Nanjing, China.

METHODS

Domain V of 23S rRNA was sequenced in MP strains collected from children diagnosed with MPP in Nanjing. Clinical and laboratory data were obtained.

RESULTS

Among the 276 MP strains, 255 (92.39%) harbored mutations, primarily A2063G in domain V of MP 23S rRNA. When children were stratified according to the presence or absence of mutations, no significant differences were found in sex, age, the MP DNA load at enrollment, lymphocyte counts, pulmonary complications, immunomodulator levels, fever duration, the duration of fever after macrolide therapy, and hospital stay. The prevalence of refractory MPP in the two groups was similar. Children with refractory MPP exhibited higher MP DNA loads than those with non-refractory MPP.

CONCLUSIONS

Despite the high prevalence of the A2063G mutation in domain V of MP 23S rRNA, mutations were not associated with the clinical characteristics of MPP. The MP DNA load significantly differed between refractory and non-refractory MPP.

Mycoplasma pneumoniae CARDS toxin exploits host cell endosomal acidic pH and vacuolar ATPase proton pump to execute its biological activities

Mycoplasma pneumoniae is the leading cause of bacterial community-acquired pneumonia among hospitalized children in the United States. It is also responsible for a spectrum of other respiratory tract disorders and extrapulmonary manifestations in children and adults. The main virulence factor of M. pneumoniae is a 591 amino acid multifunctional protein called Community Acquired Respiratory Distress Syndrome (CARDS) toxin. The amino terminal region of CARDS toxin (N-CARDS) retains ADP-ribosylating activity and the carboxy region (C-CARDS) contains the receptor binding and vacuolating activities. After internalization, CARDS toxin is transported in a retrograde manner from endosome through the Golgi complex into the endoplasmic reticulum. However, the mechanisms and criteria by which internalized CARDS toxin is transported and activated to execute its cytotoxic effects remain unknown. In this study, we used full-length CARDS toxin and its mutant and truncated derivatives to analyze how pharmacological drugs that alter pH of intracellular vesicles and electrical potential across vesicular membranes affect translocation of CARDS toxin in mammalian cells. Our results indicate that an acidic environment is essential for CARDS toxin retrograde transport to endoplasmic reticulum. Moreover, retrograde transport facilitates toxin clipping and is required to induce vacuole formation. Additionally, toxin-mediated cell vacuolation is strictly dependent on the function of vacuolar type-ATPase.

Prediction model for prolonged fever in patients with Mycoplasma pneumoniae pneumonia: a retrospective study of 716 pediatric patients

Objective

To identify patients with Mycoplasma pneumoniae pneumonia (MPP) with a risk of prolonged fever while on macrolides.

Methods

A retrospective study was performed with 716 children admitted for MPP. Refractory MPP (RMPP-3) was defined as fever persisting for > 72 h without improvement in clinical and radiologic findings after macrolide antibiotics (RMPP-3) or when fever persisted for > 120 h (RMPP-5) without improvement in clinical and radiologic findings. Radiological data, laboratory data, and fever profiles were compared between the RMPP and non-RMPP groups. Fever profiles included the highest temperature, lowest temperature, and frequency of fever. Prediction models for RMPP were created using the logistic regression method and deep neural network. Their predictive values were compared using receiver operating characteristic curves.

Results

Overall, 716 patients were randomly divided into two groups: training and test cohorts for both RMPP-3 and RMPP-5. For the prediction of RMPP-3, a conventional logistic model with radiologic grouping showed increased sensitivity (63.3%) than the model using laboratory values. Adding laboratory values in the prediction model using radiologic grouping did not contribute to a meaningful increase in sensitivity (64.6%). For the prediction of RMPP-5, laboratory values or radiologic grouping showed lower sensitivities ranging from 12.9 to 16.1%. However, prediction models using predefined fever profiles showed significantly increased sensitivity for predicting RMPP-5, and neural network models using 12 sequential fever data showed a greatly increased sensitivity (64.5%).

Conclusion

RMPP-5 could not be effectively predicted using initial laboratory and radiologic data, which were previously reported to be predictive. Further studies using advanced mathematical models, based on large-sized easily accessible clinical data, are anticipated for predicting RMPP.

Anorexia Nervosa Caused by Polymicrobial Tick-Borne Infections: A Case Study

The etiology of anorexia nervosa (AN) is multifactorial, and infections may play a contributory and possibly a prominent role. A case is presented which is indicative of a causal association between tick-borne infections and AN. This adolescent female was diagnosed with AN at an eating disorder clinic after excessive food restriction and an irrational fear of weight gain necessitating nasogastric tube feeding. Her history was consistent with systemic infections and she tested serologically positive to Borrelia burgdorferi, Babesia microti, and Mycoplasma pneumoniae; in addition, her clinical presentation was consistent with a Bartonella infection. After treatment with oral and intravenous antimicrobials, she stopped food restriction and no longer had body image concerns. Physicians should be aware of the possibility that tick-borne infections could underly a diagnosis of AN. The role of tick-borne infections in the etiology of AN warrants further study.

Inferring Active Metabolic Pathways from Proteomics and Essentiality Data

Here, we propose an approach to identify active metabolic pathways by integrating gene essentiality analysis and protein abundance. We use two bacterial species (Mycoplasma pneumoniae and Mycoplasma agalactiae) that share a high gene content similarity yet show significant metabolic differences. First, we build detailed metabolic maps of their carbon metabolism, the most striking difference being the absence of two key enzymes for glucose metabolism in M. agalactiae. We then determine carbon sources that allow growth in M. agalactiae, and we introduce glucose-dependent growth to show the functionality of its remaining glycolytic enzymes. By analyzing gene essentiality and performing quantitative proteomics, we can predict the active metabolic pathways connected to carbon metabolism and show significant differences in use and direction of key pathways despite sharing the large majority of genes. Gene essentiality combined with quantitative proteomics and metabolic maps can be used to determine activity and directionality of metabolic pathways.

•

Active metabolic bacterial pathways are identified

•

Integration of gene essentiality and proteomics allow prediction of active pathways

•

Glucose-dependent growth is restored in Mycoplasma agalactiae

•

Two Mycoplasma species show different usage of metabolic pathways

Galactocerebroside biosynthesis pathways of Mycoplasma species: an antigen triggering Guillain-Barré-Stohl syndrome

Infection by Mycoplasma pneumoniae has been identified as a preceding factor of Guillain-Barré-Stohl syndrome. The Guillain-Barré-Stohl syndrome is triggered by an immune reaction against the major glycolipids and it has been postulated that M. pneumoniae infection triggers this syndrome due to bacterial production of galactocerebroside. Here, we present an extensive comparison of 224 genome sequences from 104 Mycoplasma species to characterize the genetic determinants of galactocerebroside biosynthesis. Hidden Markov models were used to analyse glycosil transferases, leading to identification of a functional protein domain, termed M2000535 that appears in about a third of the studied genomes. This domain appears to be associated with a potential UDP-glucose epimerase, which converts UDP-glucose into UDP-galactose, a main substrate for the biosynthesis of galactocerebroside. These findings clarify the pathogenic mechanisms underlining the triggering of Guillain-Barré-Stohl syndrome by M. pneumoniae infections.

Mycoplasma-induced Stevens-Johnson syndrome/toxic epidermal necrolysis: Case-control analysis of a cohort managed in a specialized center

BACKGROUND

Mycoplasma pneumoniae (MP) infection is associated with extrapulmonary complications such as Stevens-Johnson syndrome (SJS)/toxic epidermal necrolysis (TEN).

OBJECTIVE

We evaluated the differences in epidemiology, clinical characteristics, and disease outcomes between drug-induced and Mycoplasma-related SJS/TEN.

METHODS

All patients with SJS/TEN admitted to our center between 2003 and 2016 inclusive were treated under a standardized protocol. Comparative analysis was made between patients who tested positive for MP versus a control group with negative MP serology in the presence of high-notoriety drugs defined by an algorithm for assessment of drug causality in epidermal necrolysis >5.

RESULTS

Of 180 cases of SJS/TEN patients treated in our institution, 6 had positive MP serologies and were compared to a control group of 71 cases of drug-induced SJS/TEN with an algorithm for assessment of drug causality in epidermal necrolysis score of >5. There were no significant differences in baseline characteristics, disease classification, body surface area involved, and extent of mucosal involvement. We found significant differences in mortality rates between the Mycoplasma and control groups on discharge (0% vs 22.5%, P < .001) and at 1-year follow up (0% vs 32.4%, P = .002), respectively.

LIMITATIONS

Retrospective design, small sample size.

CONCLUSION

Although recent studies have shown that MP-induced SJS/TEN is morphologically different and deserves a separate classification system, this would need to be borne out in larger prospective studies.

An Unusual Case of Myocarditis, Left Ventricular Thrombus, and Embolic Stroke Caused by Mycoplasma pneumoniae

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia, but it can affect other parts of the body. Due to the varied presentation and lack of readily available specific diagnostic tools, diagnosis is often challenging, which may lead to delay in the treatment and unfavorable outcomes. We describe such a unique case of myocarditis caused by Mycoplasma pneumoniae complicated by left ventricular thrombus and an embolic stroke without the presence of pneumonia. There is a paucity of data regarding Mycoplasma pneumoniae myocarditis and stroke in the absence of pulmonary symptoms especially in adults, calling for further studies for early diagnosis and management.

[Clinical implications of the genus Mycoplasma]

Dentro del género Mycoplasma, las especies que tradicionalmente se han relacionado con cuadros infecciosos han sido principalmente M. pneumoniae, M. genitalium, M. hominis o U. urealyticum. Sin embargo, existen otras muchas que están implicadas y, que muchas veces, son desconocidas para los profesionales sanitarios. El objetivo de esta revisión es identificar todas las especies del género Mycoplasma que se han aislado en el hombre y determinar su participación en la patología infecciosa humana.

Evaluation of a novel immunochromatographic assay using silver amplification technology for detection of Mycoplasma pneumoniae from throat swab samples in pediatric patients

Objectives

Mycoplasma pneumoniae is one of the common causative pathogens of community-acquired respiratory tract infections mainly in children and young adults. Rapid and accurate diagnostic techniques for identifying the causative pathogen would be useful for initiating treatment with an appropriate antibiotic. The purpose of the present study was to evaluate the sensitivity and specificity of a novel immunochromatographic assay using silver amplification technology using FUJI DRI-CHEM IMMUNO AG2 and FUJI DRI-CHEM IMMUNO AG cartridge Myco (FUJIFILM Co., Tokyo, Japan) for detection of M. pneumoniae.

Methods

Throat swab samples were collected from 170 pediatric patients who were diagnosed with bronchitis or pneumonia. The silver amplification immunochromatographic (SAI) assay was performed using these samples and the results were compared with those of real-time PCR. The time required for the SAI assay is approximately 20 min (5 min for sample preparation and 15 min for waiting time after starting the assay).

Results

The sensitivity and specificity of the SAI assay for detection of M. pneumoniae were 85.2 and 99.1%, respectively, and the assay showed positive and negative predictive values of 98.1 and 92.3%, respectively, compared with the results of real-time PCR. The diagnostic accuracy was 94.1%.

Conclusions

FUJI DRI-CHEM IMMUNO AG2 and FUJI DRI-CHEM IMMUNO AG cartridge Myco are appropriate for clinical use. The optimal timing of this assay is five days or more after the onset of M. pneumoniae infection. However, PCR or other molecular methods are superior, especially with regard to sensitivity and negative predictive value.

Rational design of multimeric based subunit vaccine against Mycoplasma pneumonia: Subtractive proteomics with immunoinformatics framework

Mycoplasma pneumoniae is the prevalent cause of acquired respiratory infections around the globe. A multi-epitope vaccine (MEV) must be developed to combat infections of M. pneumoniae because there is no specific disease-modifying treatment or vaccination is present. The objective of this research is to design a vaccine that targets M. pneumoniae top five highly antigenic proteins using a combination of immunological techniques and molecular docking. T-cell (HTL & CTL), B-cell, and IFN-γ of target proteins were forecasted and highly conservative epitopes were chosen for further study. For designing of final vaccine, 4LBL, 7CTL, and 5HTL epitopes were joined by linkers of KK, AAY, and GPGPG. The N-end of the vaccine was linked to an adjuvant (Cholera enterotoxin subunit B) with a linker named EAAAK to enhance immunogenicity. After the addition of adjuvants and linkers, the size of the construct was 395 amino acids. The epitopes of IFN-γ and B-cells illustrate that the model construct is optimized for cell-mediated immune or humoral responses. To ensure that the final design is safer and immunogenic, properties like non-allergens, antigenicity, and various physicochemical properties were evaluated. Molecular docking of the vaccine with the toll-like receptor 4 (TLR4) was conducted to check the compatibility of the vaccine with the receptor. Besides, in-silico cloning was utilized for validation of the credibility and proper expression of the vaccine. Furthermore, to confirm that the multi-epitope vaccine created is protective and immunogenic, this research requires experimental validation.

Pathological and Immunohistochemical Studies of Experimental Mycoplasma pneumoniae in Gerbils (Meriones unguiculatus)

Mycoplasma pneumoniae (Mp) is a leading cause of human community-acquired pneumonia. To investigate the pathogenesis of the infection, 36 gerbils were intranasally inoculated with Mp culture (30 animals) or sterile mycoplasma broth (6 animals) and euthanized from 1 to 5 weeks post infection. A morphological and immunohistochemical study was carried out in all animals to determine the cellular populations present in lung parenchyma. Polyclonal and monoclonal antibodies were used to detect antigens of Mp and CD3, CD4, CD8 and CD79 lymphocytes, as well as cells containing S100 and major histocompatibility complex class II (MHC-II) antigens. There was progressive infiltration of mononuclear cells in the lamina propria of bronchi and bronchioles, and hyperplasia of the bronchus-associated lymphoid tissue (BALT) in the infected animals. BALT contained dendritic cells immunopositive to S100 and MHC-II and numerous CD3, CD4 and CD79 lymphocytes. The immunohistochemical results showed that T lymphocytes, particularly CD4 and CD79 cells, may play a role in the immune response of gerbils against Mp. This experimental model is valuable for investigation of the pathogenesis of Mp infection and may assist in the development of therapeutic strategies.

Comparison of different detection methods for Mycoplasma pneumoniae infection in children with community-acquired pneumonia

BACKGROUND

Due to the lack of a sensitive, specific and rapid detection method, aetiological diagnosis of pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae, MP) is a constantly challenging issue. This retrospective study aimed to compare the diagnostic methods for Mycoplasma pneumoniae in children and evaluate their values.

METHODS

From November 2018 to June 2019, 830 children with community-acquired pneumonia were selected from the Department of Respiratory Medicine, Shanghai Children's Medical Center. On the first day of hospitalization, sputum, throat swab and venous blood samples were collected to analyse MP-IgM (particle agglutination, PA), MP-IgM (immune colloidal gold technique, GICT), MP-DNA, MP-RNA (simultaneous amplification and testing, SAT) and MP-DNA (real-time polymerase chain reaction, RT-PCR).

RESULTS

Among these 830 children, RT-PCR showed that the positive rate was 36.6% (304/830), in which the positive rate of macrolide resistance (A2063G mutation) accounted for 86.2% of cases (262/304). Using RT-PCR as the standard, MP-RNA (SAT) had the highest specificity (97.5%), and MP-IgM (PA) had the highest sensitivity (74.0%) and Youden index (53.7%). If MP-RNA (SAT) was combined with MP-IgM (PA), its Kappa value (0.602), sensitivity (84.2%), specificity (78.7%) and Youden index (62.9%) were higher than those of single M. pneumoniae detection.

CONCLUSIONS

Our research indicated that a combination of MP-RNA (SAT) plus MP-IgM (PA) might lead to reliable results as an early diagnostic method for children with clinical manifestations of Mycoplasma pneumoniae pneumonia.

A Review of Ureaplasma diversum: A Representative of the Mollicute Class Associated With Reproductive and Respiratory Disorders in Cattle

The Mollicutes class encompasses wall-less microbes with a reduced genome. They may infect plants, insects, humans, and animals including those on farms and in livestock. Ureaplasma diversum is a mollicute associated with decreased reproduction mainly in the conception rate in cattle, as well as weight loss and decreased quality in milk production. Therefore, U. diversum infection contributes to important economic losses, mainly in large cattle-producing countries such as the United States, China, Brazil, and India. The characteristics of Mollicutes, virulence, and pathogenic variations make it difficult to control their infections. Genomic analysis, prevalence studies, and immunomodulation assays help better understand the pathogenesis of bovine ureaplasma. Here we present the main features of transmission, virulence, immune response, and pathogenesis of U. diversum in bovines.

Quantitative proteomics analysis of Mycoplasma pneumoniae identifies potential macrolide resistance determinants

Mycoplasma pneumoniae is one of the leading causes of community-acquired pneumonia in children and adolescents. Because of the wide application of macrolides in clinical treatment, macrolide-resistant M. pneumoniae strains have become increasingly common worldwide. However, the molecular mechanisms underlying drug resistance in M. pneumoniae are poorly understood. In the present work, we analyzed the whole proteomes of macrolide-sensitive and macrolide-resistant strains of M. pneumoniae using a tandem mass tag-labeling quantitative proteomic technique, Data are available via ProteomeXchange with identifier PXD022220. In total, 165 differentially expressed proteins were identified, of which 80 were upregulated and 85 were downregulated in the drug-resistant strain compared with the sensitive strain. Functional analysis revealed that these proteins were predominantly involved in protein and peptide biosynthesis processes, the ribosome, and transmembrane transporter activity, which implicates them in the mechanism(s) of resistance of M. pneumoniae to macrolides. Our results provide new insights into drug resistance in M. pneumoniae and identify potential targets for further studies on resistance mechanisms in this bacterium.

Miller Fisher Syndrome Triggered by Infections: A Review of the Literature and a Case Report

AIM

We reported a case of Miller Fisher syndrome following a breakthrough varicella zoster virus infection in an otherwise healthy 6-year-old male. The objective of this review was to summarize the infectious etiologic agents known to trigger Miller Fisher syndrome.

METHODS

Review of the literature on infections associated with Miller Fisher syndrome.

RESULTS

We identified 762 studies after duplicates were removed. Titles, abstracts, and full texts were screened. Finally, 37 studies were included in qualitative synthesis after citations and reference list were checked. The age range of cases reported was 0-78 years, and male sex was predominant in studies where these parameters were reported. The most common causative agent was Campylobacter jejuni followed by Haemophilus influenzae.

CONCLUSIONS

Our review highlights the importance of recognizing the infections triggering Miller Fisher syndrome. We also present a unique case of Miller Fisher syndrome associated with breakthrough varicella zoster virus infection. Preventive policies may consider population immunization for certain causative agents.

The clinical characteristics of Mycoplasma pneumoniae pneumonia and its relationship between hypokalemia in west China

BACKGROUND

Mycoplasma pneumoniae (MP) is one of the most common respiratory pathogens of community acquired pneumonia (CAP) in children. The purpose of this study was to identify epidemics of Mycoplasma pneumoniae pneumonia (MPP) and to determine the relationship between hypokalemia and MPP.

METHODS

This study was retrospectively conducted from 1 August 2016 to 31 July 2018 at Bishan People's Hospital in Chongqing, China. We analyzed the demographic characteristics (age, gender), extra-pulmonary manifestations, fever duration, length of hospital stay, whole blood cell (WBC) count, C-reactive protein (CRP) levels, and lactate dehydrogenase (LDH) levels.

RESULTS

The total number of children with pneumonia was 3,385, including 570 (16.84%) patients in the MP infection group. The male-to-female ratio was 1.34:1. The peak time of MPP incidence was in autumn. The MP infection group had a significantly higher ratio of fever, higher body temperature, and longer fever duration. The number of MP-infected patients with hypokalemia was highest in spring. The length of hospital stay in the mild hypokalemia group was longer than in the normokalemia group. Furthermore, severe hypokalemia cases were all in the severe MP infection group, and the severity of MP infection and hypokalemia were positively correlated.

CONCLUSIONS

In this study, we concluded that children infected with MP were more susceptible to fever, and had a longer duration of fever. The number of MP-infected patients with mild hypokalemia peaked in spring, and affected more boys than girls. Furthermore, patients with severe hypokalemia had longer fever duration, and a correlation was found between the severity of MP infection and hypokalemia.

Evaluation on blood coagulation and C-reactive protein level among children with mycoplasma pneumoniae pneumonia by different chest imaging findings

Mycoplasma pneumoniae infection may induce a systemic hypercoagulable abnormality, like organ embolism and infarction. Indexes of blood coagulation and C-reactive protein (CRP) have been reported different between healthy people and mycoplasma pneumoniae pneumonia (MPP) patients, but this difference in MPP patients with different chest imaging findings has rarely been reported.We performed a retrospective study of 101 children with MPP and 119 controls, combined with radiological examination and blood tests, to compare the blood coagulation and CRP level among MPP children with different chest imaging findings.For the MPP children with different chest imaging findings, there were significant differences in CRP, fibrinogen (FIB) and D-dimer (D-D) levels among subgroups (P = .004, P = .008 and P < .001 respectively). The CRP level in group of interstitial pneumonia was significantly higher than that in groups of bronchopneumonia and hilar shadow thickening (P = .003 and P = .001 respectively). And the FIB and D-D values in group of lung consolidation were significantly higher than that in the other 3 groups (all P < .05). When compared with controls, the white blood cell, CRP, FIB, and D-D levels in MPP children were significantly higher, and the activated partial thromboplastin time and thrombin time levels were significantly lower (all P < .05).Our results showed that CRP level changed most significantly in group of interstitial pneumonia, whereas FIB, D-D levels changed most significantly in the lung consolidation group.

Susceptibility Analysis in Several Mouse Strains Reveals Robust T-Cell Responses After Mycoplasma pneumoniae Infection in DBA/2 Mice

Mycoplasma pneumoniae (Mp) is a highly contagious respiratory pathogen responsible for human community-acquired pneumonia. The number of antibiotic-resistant Mp strains is increasing; therefore, to develop novel therapeutics, it is crucial to precisely understand the pathogenesis of mycoplasma pneumonia. Herein, we examined the susceptibility and response to Mp among eight inbred mouse strains. Following infection, the bacterial load in the bronchoalveolar lavage fluid (BALF) from DBA/2 mice was higher than that in the other tested strains such as BALB/c mice, which are frequently used in Mp research. In contrast, the numbers of CD45⁺ immune cells and neutrophils in BALF were comparable between BALB/c and DBA/2 mice, with lower numbers observed in C57BL/6J and CBA/N mice than in BALB/c mice. Among the tested strains, the BALF level of interleukin 12 subunit p40 was highest in DBA/2 mice; however, significant differences in other cytokines levels were not observed between BALB/c and DBA/2 mice. After Mp infection, Mp-specific Th1 and Th17 responses were significantly enhanced in DBA/2 mice when compared with BALB/c mice. Furthermore, prior infection with Mp increased the number of neutrophils in BALF after the reinfection of DBA/2 mice through an Mp-specific CD4⁺ T cell-dependent mechanism. Thus, DBA/2 may be an appropriate strain for evaluating Mp infection. Moreover, a comparison of responses revealed by various inbred mouse strains could be useful for elucidating the pathogenesis of Mycoplasma pneumonia.

Acute respiratory distress syndrome during the COVID-19 pandemic: not only SARS-CoV-2

A previously healthy 30-year-old woman developed severe ARDS at the beginning of the COVID-19 pandemic. SARS-CoV-2 infection was suspected, but testing was negative. Mycoplasma pneumoniae was detected by PCR in bronchoalveolar lavage fluid and blood. This case illustrates that M. pneumoniae infection can progress to septicemia and ARDS with severe respiratory failure in young healthy adults.

Clinical Predictors of Wheezing Among Children Infected With Mycoplasma Pneumoniae

Background: Mycoplasma pneumoniae (MP) not only was a common pathogen of respiratory tract infections, but also could trigger the exacerbation of asthmatic symptoms in children with or without asthma. Objective: This study aimed to identify possible risk factors associated with wheezing among children diagnosed with MP infection. Methods: A retrospective analysis of medical records of children aged 28 days to 18 years old who visited the Shanghai Children's Hospital between January 2019 and January 2020 was carried out, and all children were then classified into three groups: two wheezing groups (with or without MP infection) and a non-wheezing group with MP infection. Information including patient's demographics, clinical features, laboratory data, and radiography findings was extracted from the electronic medical record system. Chest radiographs were reviewed independently by two board-certified, blinded pediatric radiologists. Results: A total of 1,512 patients were included in our study, and 21.9% of them belonged to the wheezing group without MP infection. Among 1,181 patients with MP infection, 295 people (25.0%) suffered from wheezing, and males accounted for 61%. Through the multivariable logistic regression analyses, we found that six variables were positively associated with wheezing attacks in children with MP infection: male gender (likelihood ratio [LR] = 2.124, 95% confidence interval [CI]: 1.478-3.053), history of allergy (LR= 3.301, 95% CI: 2.206-4.941), history of wheezing (LR = 7.808, 95% CI: 5.276-11.557), autumn in reference to summer (LR = 2.414, 95% CI: 1.500-3.885), non-end-point infiltration in reference to consolidation or pleural effusion (LR = 1.982, 95% CI: 1.348-2.914), and infiltration scope (LR = 1.773, 95% CI: 1.293-2.432). However, the model showed that the probability of wheezing after MP infection decreased as age increased (LR = 0.257, 95% CI: 0.196-0.337). Moreover, the area under the curve (AUC) of the regression model was as high as 0.901 (0.847-0.955). Conclusion: The model integrated with factors including gender, age, season, radiological patterns, infiltration scope, and history of allergy performed well in predicting wheezing attack after MP infection in children.

Mycoplasma gallisepticum infection triggered histopathological changes, oxidative stress and apoptosis in chicken thymus and spleen

Previous studies mainly focused on the inflammatory responses caused by Mycoplasma gallisepticum (MG) in the chicken respiratory mucosa, setting the stage for chronic infection and disease manifestation. However, the underlying mechanism is still unknown. Spleen and thymus are important immune organs, which play a critical role in eliciting protective immune responses to ensure healing process and elimination of harmful stimuli. In the present study, the effects of MG infection on chicken spleen and thymus were investigated. The results showed that MG infection reduced antioxidant activities and induced oxidative stress in the spleen and thymus tissues. Histological examination showed normal morphology of chicken spleen and thymus in control group compared to MG infection group. In contrast, increased number of necrotic and nuclear debris, lymphocytolysis, prominent reticuloepithelial cells and loose arrangement of cells in the spleen and thymus were seen in MG-infected chickens. Ultrastructural analysis indicated nuclear and mitochondrial damage including mitochondrial swelling, deformation of nuclear membrane and congestion of chromatin material in MG infection group. The mRNA and protein expression of apoptosis-related genes were significantly upregulated in the spleen and thymus of MG-infected chickens compared to control group. Moreover, Terminal deoxynucleotidyl transferase-mediated dUTP nick endlabeling (TUNEL) assay results suggested that MG infection increased the number of positive-stained nuclei in the spleen and thymus. Meanwhile, the mRNA expression of mitochondrial dynamics in the spleen and thymus were altered by MG infection. In summary, these results showed that MG induced oxidative stress and apoptosis, which could be the possible causes associated with the immune damage, structural impairment and disease pathogenesis of MG infection.

Immunological Features of Pediatric Interstitial Pneumonia Due to Mycoplasma pneumoniae

Background: Inflammatory response, oxidative stress, and immunologic mechanism are involved in the pathogenesis of Mycoplasma pneumoniae pneumonia (MPP). However, the role of immune system of pediatric interstitial pneumonia due to M. pneumoniae infections remains poorly understood. The aim of this study was to analyze the immunologic features of pediatric interstitial pneumonia due to Mycoplasma pneumoniae (M. pneumoniae). Methods: A retrospective study was conducted on a primary cohort of children with MPP. Propensity score analysis was performed to match interstitial pneumonia and pulmonary consolidation children. Results: The clinical characteristics strongly associated with the development of interstitial pneumonia were boys, age >5 years, wheezing history, hydrothorax free, lymphocytes (>3.0 × 10⁹/L), CD19⁺ (>0.9 × 10⁹/L), CD3⁺ (>2.5 × 10⁹/L), CD4⁺ (>1.5 × 10⁹/L), CD8⁺ (>0.9 × 10⁹/L), interleukin-6 (IL-6, <30 pg/ml), IL-10 (<6 pg/ml), and interferon-γ (IFN-γ, <15 pg/ml). After propensity score analysis, children with interstitial pneumonia showed significantly higher CD19⁺, CD3⁺, and CD4⁺ T cell counts, and lower serum IL-6, IL-10, and IFN-γ levels. The final regression model showed that only CD4⁺ T cells (>1.5 × 10⁹/L, OR = 2.473), IFN-γ (<15 pg/ml, OR = 2.250), and hydrothorax free (OR = 14.454) were correlated with the development of interstitial pneumonia among children with MPP. Conclusions: The M. pneumoniae-induced interstitial pneumonia showed increased CD4⁺ T cells and lower serum IFN-γ level. Specific immunologic profiles could be involved in the development of pediatric interstitial pneumonia due to M. pneumoniae infections.

Mycoplasma pneumoniae: Atypical Pathogen in Community Acquired Pneumonia

Mycoplasma pneumoniae is a one of most common reasons of respiratory tract infections in both adolescents and children with severity ranged from moderate to high. Many facts in the previous years regarding infections were induced via this organism having extra pathogenic mechanisms. Clinically, resistance to macrolide has produced internationally and represents a treatment trouble. Antimicrobial sensitivity checking out techniques have been applied, and novel antibiotics which are effective towards M. pneumoniae are present processing development. That evaluate concentrates on the several trends occurring in the previous quite a few years which beautify the grasp of that microorganism, which is one of the smallest pathogenic bacteria; however, is of extreme medical significance.

Central Nervous System Vasculitis as a Rare Presentation of Mycoplasma pneumoniae: A Case Report

Mycobacteria pneumoniae (MP) commonly causes upper and lower respiratory tract infections. The clinical manifestation is classified as pulmonary and extrapulmonary. These manifestations vary according to the involved system. MP may affect one system or more at a time. Commonly prodromal respiratory symptoms precede systemic involvement. Central nervous system involvement in uncommon. This report is presenting a rare case of central nervous system vasculitis secondary to MP, highlighting the diagnosis and management with a succinct literature review.

Unexpected Mycoplasma hominis infection in two renal transplant recipients traced back to the same donor by whole-genome sequencing

Mycoplasma hominis is a common colonizer of the lower genitourinary tract. Although its clinical relevance for causing urogenital infections in immunocompetent individuals is controversial, this bacterium has been involved in severe invasive infections in allograft recipients. In this report, we describe two cases of M. hominis infection in two young renal transplant recipients within the first month post-transplant. Although at first no epidemiological link between the two cases had been suspected, whole-genome sequencing (WGS) analysis showed that both isolates were identical, highly suggestive of an origin with the common organ donor.

Outbreak of Mycoplasma pneumoniae at a military academy

In 2019, an outbreak of Mycoplasma pneumoniae occurred at a military academy in China. The attack rate (10.08%,60/595) was significantly different among the units. High-intensity training and crowded environments to which cadets are exposed are the high risk factors for the outbreak of M. pneumoniae. In-time prevention and control measures effectively controlled the spread of the epidemic.

Mycoplasma Pneumoniae-Induced Rash and Mucositis: A Longitudinal Perspective and Proposed Management Criteria

PURPOSE

To evaluate the natural history and ophthalmologic morbidity of Mycoplasma pneumoniae-induced rash and mucositis (MIRM) and propose a treatment algorithm.

DESIGN

Retrospective, interventional case series.

METHODS

Retrospective chart review of all MIRM patients examined by the department of ophthalmology at a tertiary children's hospital. Diagnosis was established clinically concomitant with either positive Mycoplasma pneumoniae IgM or PCR testing from January 1, 2010, until December 31, 2019. The main outcome measures were best-corrected visual acuity, long-term ocular sequelae, and duration and type of ophthalmic intervention.

RESULTS

There were 15 patients (10 male and 5 female) aged 10.9 ± 4.2 years who had primary episodes of MIRM; of those, 4 had multiple episodes. All patients required topical steroid treatment, 3 required amniotic membrane transplantation, and 1 patient underwent placement of a sutureless biologic corneal badage device. There were no patients who suffered visual loss, but 1 was left with mild symblephara near the lateral canthus in each eye and 2 others had scarring of the eyelid margins and blepharitis.

CONCLUSIONS

The ocular morbidity is significantly less in MIRM than in other closely related syndromes such as erythema multiforme, Stevens-Johnson syndrome, and toxic epidermal necrolysis. However, these patients still require close observation and a low threshold for intervention to avoid permanent ophthalmic sequelae and possible blindness.

Correlation Between the Clinical Severity, Bacterial Load, and Inflammatory Reaction in Children with Mycoplasma Pneumoniae Pneumonia

Given the lack of defining features in the clinical manifestations and radiographic findings for children with mycoplasma pneumoniae pneumonia (MPP), quantitative polymerase chain reaction (qPCR) has become a useful diagnostic method. This study was performed to explore the relationship between the qPCR findings, clinical symptoms, and inflammatory markers in children with MPP. Four hundred children with MPP have been enrolled in this retrospective analysis. All clinical and analytical information, including mycoplasma pneumoniae (MP) PCR results, has been collected. Based on the PCR results, the patients were divided into groups with load values (copy number) < 10⁵ (54 cases), ≥10⁵ and <10⁶ (71 cases), ≥10⁶ and <10⁷ (112 cases), ≥10⁷ and ≤10⁸ (114 cases), and >10⁸ (49 cases). The clinical features (including symptoms and signs) and inflammatory indicators were compared among the groups. The incidence of high fever (above 39°C), thermal peak during the entire hospitalization period, fever duration, days of hospitalization, and plasma lactate dehydrogenase (LDH) levels were statistically correlated with the MP PCR load value in children with MPP. The analysis of relevance degree showed the correlative order as a thermal peak of hospitalization > duration of fever > period of hospitalization > LDH value > C-reactive protein value. The host immune response was significantly greater in the complication group than in the non-complication group.

Model-driven design allows growth of Mycoplasma pneumoniae on serum-free media

Mycoplasma pneumoniae is a slow-growing, human pathogen that causes atypical pneumonia. Because it lacks a cell wall, many antibiotics are ineffective. Due to its reduced genome and dearth of many biosynthetic pathways, this fastidious bacterium depends on rich, undefined medium for growth, which makes large-scale cultivation challenging and expensive. To understand factors limiting growth, we developed a genome-scale, constraint-based model of M. pneumoniae called iEG158_mpn to describe the metabolic potential of this bacterium. We have put special emphasis on cell membrane formation to identify key lipid components to maximize bacterial growth. We have used this knowledge to predict essential components validated with in vitro serum-free media able to sustain growth. Our findings also show that glycolysis and lipid metabolism are much less efficient under hypoxia; these findings suggest that factors other than metabolism and membrane formation alone affect the growth of M. pneumoniae. Altogether, our modelling approach allowed us to optimize medium composition, enabled growth in defined media and streamlined operational requirements, thereby providing the basis for stable, reproducible and less expensive production.

A RAGE Based Strategy for the Genome Engineering of the Human Respiratory Pathogen Mycoplasma pneumoniae

Genome engineering of microorganisms has become a standard in microbial biotechnologies. Several efficient tools are available for the genetic manipulation of model bacteria such as Escherichia coli and Bacillus subtilis, or the yeast Saccharomyces cerevisiae. Difficulties arise when transferring these tools to nonmodel organisms. Synthetic biology strategies relying on genome transplantation (GT) aim at using yeast cells for engineering bacterial genomes cloned as artificial chromosomes. However, these strategies remain unsuccessful for many bacteria, including Mycoplasma pneumoniae (MPN), a human pathogen infecting the respiratory tract that has been extensively studied as a model for systems biology of simple unicellular organisms. Here, we have designed a novel strategy for genome engineering based on the recombinase-assisted genomic engineering (RAGE) technology for editing the MPN genome. Using this strategy, we have introduced a 15 kbp fragment at a specific locus of the MPN genome and replaced 38 kbp from its genome by engineered versions modified either in yeast or in E. coli. A strain harboring a synthetic version of this fragment cleared of 13 nonessential genes could also be built and propagated in vitro. These strains were depleted of known virulence factors aiming at creating an avirulent chassis for SynBio applications. Such a chassis and technology are a step forward to build vaccines or deliver therapeutic compounds in the lungs to prevent or cure respiratory diseases in humans.

Mycoplasmas-Host Interaction: Mechanisms of Inflammation and Association with Cellular Transformation

Mycoplasmas are the smallest and simplest self-replicating prokaryotes. Located everywhere in nature, they are widespread as parasites of humans, mammals, reptiles, fish, arthropods, and plants. They usually exhibiting organ and tissue specificity. Mycoplasmas belong to the class named Mollicutes (mollis = soft and cutis = skin, in Latin), and their small size and absence of a cell wall contribute to distinguish them from other bacteria. Mycoplasma species are found both outside the cells as membrane surface parasites and inside the cells, where they become intracellular residents as "silent parasites". In humans, some Mycoplasma species are found as commensal inhabitants, while others have a significant impact on the cellular metabolism and physiology. Mollicutes lack typical bacterial PAMPs (e.g., lipoteichoic acid, flagellin, and some lipopolysaccharides) and consequently the exact molecular mechanisms of Mycoplasmas' recognition by the cells of the immune system is the subjects of several researches for its pathogenic implications. It is well known that several strains of Mycoplasma suppress the transcriptional activity of p53, resulting in reduced apoptosis of damaged cells. In addition, some Mycoplasmas were reported to have oncogenic potential since they demonstrated not just accumulation of abnormalities but also phenotypic changes of the cells. Aim of this review is to provide an update of the current literature that implicates Mycoplasmas in triggering inflammation and altering critical cellular pathways, thus providing a better insight into potential mechanisms of cellular transformation.

[Influencing factors for the clinical effect of bronchoalveolar lavage in children with Mycoplasma pneumoniae pneumonia and atelectasis]

OBJECTIVE

To study the influencing factors for the clinical effect of bronchoalveolar lavage (BAL) in children with Mycoplasma pneumoniae pneumonia (MPP) and atelectasis.

METHODS

A total of 75 children with MPP and atelectasis were divided into a good response group with 51 children and a poor response group with 24 children according to the clinical effect of BAL treatment. LASSO logistic regression analysis was used to investigate the factors influencing the clinical effect of BAL treatment. The receiver operating characteristic (ROC) curve and restricted cubic spline model analysis were used to evaluate the value of the course of the disease at the time of BAL treatment in predicting the clinical effect of BAL treatment.

RESULTS

Compared with the good response group, the poor response group had a significantly lower percentage of lymphocytes in bronchoalveolar lavage fluid, a significantly higher proportion of children with atelectasis of two or more lung lobes or stenosis of the bronchial cavity or opening caused by inflammation, and a significantly longer course of the disease at the time of BAL treatment and azithromycin treatment (P<0.05). The LASSO logistic regression analysis showed that a prolonged course of the disease at the time of BAL treatment (OR=1.23), atelectasis of two or more lung lobes (OR=11.99), and stenosis of the bronchial cavity or opening caused by inflammation (OR=5.31) were independent risk factors for poor clinical effect of BAL treatment (P<0.05). The ROC curve analysis showed that the course of disease of ≥11.5 days at the time of BAL treatment suggested a poor clinical effect of BAL treatment, with a sensitivity of 91.7% and a specificity of 54.9%. The restricted cubic spline model analysis showed that there was a non-linear dose-response relationship between the course of disease at the time of BAL treatment and the clinical effect of BAL treatment (P<0.05).

CONCLUSIONS

Early BAL treatment may have a good clinical effect in children with MPP and atelectasis. Atelectasis of two or more lung lobes and inflammation-induced stenosis of the bronchial cavity or opening shown under bronchoscope may indicate a poor clinical effect of BAL treatment.

[Influencing factors for the clinical effect of bronchoalveolar lavage in children with Mycoplasma pneumoniae pneumonia and atelectasis]

OBJECTIVE

To study the influencing factors for the clinical effect of bronchoalveolar lavage (BAL) in children with Mycoplasma pneumoniae pneumonia (MPP) and atelectasis.

METHODS

A total of 75 children with MPP and atelectasis were divided into a good response group with 51 children and a poor response group with 24 children according to the clinical effect of BAL treatment. LASSO logistic regression analysis was used to investigate the factors influencing the clinical effect of BAL treatment. The receiver operating characteristic (ROC) curve and restricted cubic spline model analysis were used to evaluate the value of the course of the disease at the time of BAL treatment in predicting the clinical effect of BAL treatment.

RESULTS

Compared with the good response group, the poor response group had a significantly lower percentage of lymphocytes in bronchoalveolar lavage fluid, a significantly higher proportion of children with atelectasis of two or more lung lobes or stenosis of the bronchial cavity or opening caused by inflammation, and a significantly longer course of the disease at the time of BAL treatment and azithromycin treatment (P<0.05). The LASSO logistic regression analysis showed that a prolonged course of the disease at the time of BAL treatment (OR=1.23), atelectasis of two or more lung lobes (OR=11.99), and stenosis of the bronchial cavity or opening caused by inflammation (OR=5.31) were independent risk factors for poor clinical effect of BAL treatment (P<0.05). The ROC curve analysis showed that the course of disease of ≥11.5 days at the time of BAL treatment suggested a poor clinical effect of BAL treatment, with a sensitivity of 91.7% and a specificity of 54.9%. The restricted cubic spline model analysis showed that there was a non-linear dose-response relationship between the course of disease at the time of BAL treatment and the clinical effect of BAL treatment (P<0.05).

CONCLUSIONS

Early BAL treatment may have a good clinical effect in children with MPP and atelectasis. Atelectasis of two or more lung lobes and inflammation-induced stenosis of the bronchial cavity or opening shown under bronchoscope may indicate a poor clinical effect of BAL treatment.

A 20-Mer Peptide Derived from the Lectin Domain of SP-A2 Decreases Tumor Necrosis Factor Alpha Production during Mycoplasma pneumoniae Infection

Human surfactant protein-A2 (hSP-A2) is a component of pulmonary surfactant that plays an important role in the lung's immune system by interacting with viruses, bacteria, and fungi to facilitate pathogen clearance and by downregulating inflammatory responses after an allergic challenge. Genetic variation in SP-A2 at position Gln223Lys is present in up to ∼30% of the population and has been associated with several lung diseases, such as asthma, pulmonary fibrosis, and lung cancer (M. M. Pettigrew, J. F. Gent, Y. Zhu, E. W. Triche, et al., BMC Med Genet 8:15, 2007, https://bmcmedgenet.biomedcentral.com/articles/10.1186/1471-2350-8-15; Y. Wang, P. J. Kuan, C. Zing, J. T. Cronkhite, et al., Am J Hum Genet 84:52-59, 2009, https://www.cell.com/ajhg/fulltext/S0002-9297(08)00595-8). Previous work performed by our group showed differences in levels of SP-A binding to non-live mycoplasma membrane fractions that were dependent on the presence of a lysine (K) or a glutamine (Q) at amino acid position 223 in the carbohydrate region of SP-A2. On the basis of these differences, we have derived 20-amino-acid peptides flanking this region of interest in order to test the ability of each to regulate various immune responses to live Mycoplasma pneumoniae in SP-A knockout mice and RAW 264.7 cells. In both models, the 20-mer containing 223Q significantly decreased both tumor necrosis factor alpha (TNF-α) mRNA levels and protein levels in comparison to the 20-mer containing 223K during M. pneumoniae infection. While neither of the 20-mer peptides (223Q and 223K) had an effect on p38 phosphorylation during M. pneumoniae infection, the 223Q-20mer peptide significantly reduced NF-κB p65 phosphorylation in both models. Taken together, our data suggest that small peptides derived from the lectin domain of SP-A2 that contain the major allelic variant (223Q) maintain activity in reducing TNF-α induction during M. pneumoniae infection.

The correlation between vitamin a status and refractory Mycoplasma Pneumoniae pneumonia (RMPP) incidence in children

Background

Vitamin A plays a pivotal role in respiratory infection, accurate estimation of vitamin A status was recommended in planning and implementing interventions. As infections affect serum vitamin A productions, the real status need to be adjusted by acute phase protein (APP). Mycoplasma pneumoniae is an important cause of respiratory infection in children, the association between vitamin A concentrations and refractory Mycoplasma pneumoniae pneumonia (RMPP) remains unclear.

Methods

181 MPP patients were enrolled in this retrospective study, adjusted vitamin A concentrations and other parameters were compared between RMPP and general-MPP (GMPP) patients. Multivariate logistic regression test was performed to evaluate the association between vitamin A levels and RMPP incidence, linear correlation tests were applied to evaluate correlation between vitamin A concentrations and fever duration, length of stay (LOS).

Results

Vitamin A concentrations in RMPP group were significantly lower than those in GMPP patients (P < 0.05), vitamin A (OR = 0.795, 95% C. I 0.669–0.946) and CRP (OR = 1.050, 95% C. I 1.014–1.087) were independently associated with RMPP incidence. Linear correlation tests found vitamin A concentrations were negatively correlated with fever duration and LOS (P < 0.001).

Conclusions

Serum vitamin A concentrations were independently associated with RMPP incidence, which may correlate with reduced incidence of RMPP.

Interleukin-23 derived from CD16+ monocytes drives IL-17 secretion by TLR4 pathway in children with mycoplasma pneumoniae pneumonia

AIMS

The study aimed to investigate whether IL-23 is amplified in monocyte subsets of MP pneumonia and to determine its relevant pathway.

MATERIALS AND METHODS

We firstly analyze the IL-23p19 expression in monocyte subgroups in MP pneumonia patients and healthy controls subjects by using flow cytometry. Then, we also analyzed the percentage of IL-17⁺γδT cells and Th17 cells in patients with MP pneumonia and controls subjects. At the same time, the relation between IL-23 and IL-17 were also assessed. Furthermore, we constructed the recombinant community-acquired respiratory distress syndrome (CARDS) toxin and intend to stimulate peripheral blood mononuclear cells and RAW264.7 cells in vitro. IL-23p19 was detected by flow cytometry and the mRNA levels were measured by real-time PCR. Finally, TLR4 pathway was also investigated by TAK242 inhibitor.

KEY FINDINGS

It turned out that the expression of IL-23p19 was increased in CD14^brightCD16⁺ monocyte of MP pneumonia patients than controls subjects. The patients with MP pneumonia had significantly higher the percentage of IL-17⁺γδT cells and Th17 cells than controls subjects. Interestingly, the levels of IL-23 were positively related to IL-17 in MP pneumonia patients. CD16⁺ monocytes and RAW264.7 cells, respectively can be induced by CARDS toxin to secrete IL-23 by TLR4 pathway in vitro.

SIGNIFICANCE

These results indicated that IL-23-IL-17⁺γδT/Th17 axis may play a role in the pathogenesis of MP pneumonia, whereas IL-23 derived from CD16⁺ monocytes was expanded in MP pneumonia by TLR4 pathway.

Persistence in Livestock Mycoplasmas—a Key Role in Infection and Pathogenesis

Purpose of Review

Mycoplasma, economically important pathogens in livestock, often establishes immunologically complex persistent infections that drive their pathogenesis and complicate prophylaxis and therapy of the caused diseases. In this review, we summarize some of the recent findings concerning cellular and molecular persistence mechanisms related to the pathogenesis of mycoplasma infections in livestock.

Recent Findings

Data from recent studies prove several mechanisms including intracellular lifestyle, immune dysregulation, and autoimmunity as well as microcolony and biofilm formation and apoptosis of different host cell types as important persistence mechanisms in several clinically significant Mycoplasma species, i.e., M. bovis, M. gallisepticum, M. hyopneumoniae, and M. suis.

Summary

Evasion of the immune system and the establishment of persistent infections are key features in the pathogenesis of livestock mycoplasmas. In-depth knowledge of the underlying mechanisms will provide the basis for the development of therapy and prophylaxis strategies against mycoplasma infections.

Epidemiology and molecular identification of mycoplasma pneumoniae associated with respiratory infections in Zhejiang province, China, 2008-2017

Introduction

Mycoplasma pneumoniae is a common cause of respiratory infections in humans. The aim of this study was to investigate the infection of Mycoplasma pneumoniae (MP) in patients with acute respiratory tract infections in Zhejiang Province from 2008 to 2017, and to provide evidence for the early diagnosis and prevention of MP pneumonia.

Methods

MP‐DNA was detected in nasopharyngeal swabs of patients with acute respiratory tract infection by real‐time fluorescent PCR (TaqMan probe). Statistical analysis and epidemiological investigation were carried out on the test results.

Results

There were 10 296 patients with acute respiratory tract infection in Zhejiang Provincial People's Hospital from 2008 to 2017, including 4387 females and 5909 males. A total of 1251 MP‐DNA–positive patients were detected, with a total positive rate of 12.2% (1251/10296). Among 1251 patients with MP infection, 571 were female positive, with an average positive rate of 13.0% (571/4387), and 680 were male positive, with a positive rate of 11.5% (680/5909). From 2008 to 2017, the positive rates were 22.8% (33 cases), 20.9% (211 cases), 20.9% (350 cases), 5.5% (70 cases), 11.7% (136 cases), 15.2% (190 cases), 7.8% (94 cases), 5.9% (62 cases), 7.8% (56 cases), and 6.0% (49 cases), respectively. Of 1251 MP‐DNA–positive patients, 1243 (99.4%) were younger than 18 years old.

Conclusions

Mycoplasma pneumoniae infection mainly occurs from late summer to autumn and in the age below 18 years, suggesting that early diagnosis and prevention of MP infection in adolescents should be emphasized.