Pathogenesis of neurologic manifestations of Mycoplasma pneumoniae infection

Neuroinfectious Diseases in Children: Pathophysiology, Outcomes, and Global Challenges

Pathogens with affinity for the central nervous system (CNS) in children are diverse in their mechanisms of infecting and attacking the brain. Infections can reach the CNS via hematogenous routes, transneurally thereby avoiding the blood-brain barrier, and across mucosal or skin surfaces. Once transmission occurs, pathogens can wreak havoc both by direct action on host cells and via an intricate interplay between the protective and pathologic actions of the host's immune system. Pathogen prevalence varies depending on region, and susceptibility differs based on epidemiologic factors such as age, immune status, and genetics. In addition, some infectious diseases are monophasic, whereas others may lie dormant for years, thereby causing a dynamic effect on outcomes. Outcomes in survivors are highly variable for each particular pathogen and depend on the vaccination and immune status of the patient as well as the speed by which the patient receives evidence-based treatments. Given pathogens cause communicable diseases that can cause morbidity and mortality on a population level when spread, the burden is often the greatest and the outcomes the worst in low-resource settings. Here we will focus on the most common infections with a propensity to affect a child's brain, the pathologic mechanisms by which they do so, and what is known about the developmental outcomes in children who are affected by these infections.

Global research trends of Mycoplasma pneumoniae pneumonia in children: a bibliometric analysis

BACKGROUND

Mycoplasma pneumoniae pneumonia (MPP), attributable to Mycoplasma pneumoniae (MP), represents a predominant form of community-acquired pneumonia in pediatric populations, thereby posing a significant threat to pediatric health. Given the burgeoning volume of research literature associated with pediatric MPP in recent years, it becomes imperative to undertake a bibliometric analysis aimed at delineating the current research landscape and emerging trends, thereby furnishing a framework for subsequent investigations.

METHODS

A comprehensive literature search targeting pediatric MPP was conducted in the Web of Science Core Collection. After the removal of duplicate entries through Endnote software, the remaining articles were subject to scientometric analysis via Citespace software, VOSviewer software and R language, focusing on variables such as publication volume, contributing nations, institutions and authors, references and keywords.

RESULTS

A total of 1,729 articles pertinent to pediatric MPP were included in the analysis. China and the United States emerged as the nations with the highest publication output. Italian scholar Susanna Esposito and Japanese scholar Kazunobu Ouchi were the most influential authors in the domain of pediatric MPP. Highly-cited articles primarily focused on the epidemiological investigation of pediatric MPP, the clinical characteristics and treatment of macrolide-resistant MPP, and biomarkers for refractory Mycoplasma pneumoniae pneumonia (RMPP). From the corpus of 1,729 articles, 636 keywords were extracted and categorized into ten clusters: Cluster #0 centered on molecular-level typing of macrolide-resistant strains; Cluster #1 focused on lower respiratory tract co-infections; Clusters #2 and #6 emphasized other respiratory ailments caused by MP; Cluster #3 involved biomarkers and treatment of RMPP; Clusters #4 and #9 pertained to extrapulmonary complications of MPP, Clusters #5 and #7 addressed etiological diagnosis of MPP, and Cluster #8 explored pathogenic mechanisms.

CONCLUSIONS

The past few years have witnessed extensive attention directed towards pediatric MPP. Research in pediatric MPP principally revolves around diagnostic techniques for MP, macrolide resistance, complications of MPP, treatment and diagnosis of RMPP, and elucidation of pathogenic mechanisms. The present study provides pediatric clinicians and researchers with the research status and focal points in this field, thereby guiding the orientation of future research endeavors.

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

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

Diagnostic investigation of Mycoplasma hyorhinis as a potential pathogen associated with neurological clinical signs and central nervous system lesions in pigs

Mycoplasma hyorhinis (M. hyorhinis) is a commensal of the upper respiratory tract in swine with the typical clinical presentations of arthritis and polyserositis in postweaning pigs. However, it has also been associated with conjunctivitis and otitis media, and recently has been isolated from meningeal swabs and/or cerebrospinal fluid of piglets with neurological signs. The objective of this study is to evaluate the role of M. hyorhinis as a potential pathogen associated with neurological clinical signs and central nervous system lesions in pigs. The presence of M. hyorhinis was evaluated in a clinical outbreak and a six-year retrospective study by qPCR detection, bacteriological culture, in situ hybridization (RNAscope®), and phylogenetic analysis and with immunohistochemistry characterization of the inflammatory response associated with its infection. M. hyorhinis was confirmed by bacteriological culture and within central nervous system lesions by in situ hybridization on animals with neurological signs during the clinical outbreak. The isolates from the brain had close genetic similarities from those previously reported and isolated from eye, lung, or fibrin. Nevertheless, the retrospective study confirmed by qPCR the presence of M. hyorhinis in 9.9% of cases reported with neurological clinical signs and histological lesions of encephalitis or meningoencephalitis of unknown etiology. M. hyorhinis mRNA was confirmed within cerebrum, cerebellum, and choroid plexus lesions by in situ hybridization (RNAscope®) with a positive rate of 72.7%. Here we present strong evidence that M. hyorhinis should be included as a differential etiology in pigs with neurological signs and central nervous system inflammatory lesions.

Clinical Characteristics of Macrolide-Refractory Mycoplasma pneumoniae Pneumonia in Korean Children: A Multicenter Retrospective Study

Mycoplasma pneumoniae is a major causative pathogen of community-acquired pneumonia in children, and the treatment of choice is macrolides. There is an increasing trend in reports of refractory clinical responses despite macrolide treatment due to the emergence of macrolide-resistant M. pneumoniae. Early discrimination of macrolide-refractory M. pneumoniae pneumonia (MrMP) from macrolide-sensitive M. pneumoniae pneumonia (MSMP) is vital; however, testing for macrolide susceptibility at the time of admission is not feasible. This study aimed to identify the characteristics of MrMP in Korean children, in comparison with those of MSMP. In this multicenter study, board-certified pediatric pulmonologists at 22 tertiary hospitals reviewed the medical records from 2010 to 2015 of 5294 children who were hospitalized with M. pneumoniae pneumonia and administered macrolides as the initial treatment. One-way analysis of variance and the Kruskal-Wallis test were used to compare differences between groups. Of 5294 patients (mean age, 5.6 years) included in this analysis, 240 (4.5%), 925 (17.5%), and 4129 (78.0%) had MrMP, macrolide-less effective M. pneumoniae pneumonia, and MSMP, respectively. Compared with the MSMP group, the MrMP group had a longer fever duration, overall (13.0 days) and after macrolide use (8.0 days). A higher proportion of MrMP patients had respiratory distress, pleural effusion, and lobar pneumonia. The mean aspartate aminotransferase, alanine aminotransferase, lactate dehydrogenase, and C-reactive protein levels were the highest in the MrMP group, along with higher incidences of extrapulmonary manifestations and atelectasis (during and post infection). Pre-existing conditions were present in 17.4% (n = 725/4159) of patients, with asthma being the most common (n = 334/4811, 6.9%). This study verified that MrMP patients show more severe initial radiographic findings and clinical courses than MSMP patients. MrMP should be promptly managed by agents other than macrolides.

Stevens-Johnson Syndrome and Stroke Related to Mycoplasma

Mycoplasma pneumonia usually causes asymptomatic to mild respiratory tract infection. However, nonrespiratory manifestations are not rare with involvement of various organ including skin, cardiovascular, central nervous system. We are presenting a 43-year-old male who presented with diffuse rash, sever mucositis, confusion, and complicated by ischemic stroke; also, review of mycoplasma related stroke and Stevens-Johnson syndrome.

A Study Based on Metabolomics, Network Pharmacology, and Experimental Verification to Explore the Mechanism of Qinbaiqingfei Concentrated Pills in the treatment of Mycoplasma Pneumonia

Qinbaiqingfei concentrated pills (QB) are a commonly used medicine for the treatment of mycoplasma pneumonia in China, and the mechanism of action of QB needs to be studied further. Therefore, we use a combination of metabolomics and network pharmacology to clarify the mechanism of QB. Nontarget metabolomics studies were performed on rat serum, urine, and lung tissues, and 56 therapeutic biomarkers were found. Subsequently, the components of QB absorbed into the blood and lung tissues were clarified, and based on this finding, the core target of network pharmacology was predicted. The enrichment analysis of biomarkers–genes finally confirmed their close relationship with the NF-κB signaling pathway. By western blotting expression of the proteins in the lung tissue–related signaling pathways, it is finally confirmed that QB inhibits the NF-κB signaling pathway through SIRT1, IL-10 and MMP9, CTNNB1, EGFR, and other targets. It plays a role in regulating immunity, regulating metabolism, and treating diseases.

Mycoplasma infection and ocular surface diseases: a nationwide cohort study

Whether patients with Mycoplasma infection have an increased risk of ocular surface ulcers. Using a nation-wide database, we identified patients with a new diagnosis of Mycoplasma infection between 1997 and 2013, and compared them with age-, sex-, and index year-matched subjects without the infection. Cox proportional regression was performed to compare the risk of corneal diseases between the two cohorts. The incidence of corneal diseases was significantly higher in the 4223 patients with Mycoplasma infection than in the 16,892 patients without (7.28 vs. 5.94 per 1000 person-years, P < 0.01). The adjusted hazard ratio for the risk of corneal diseases in the study cohort was 1.21 times higher (95% CI 1.02-1.44) than that in the comparison cohort. Mycoplasma infection might be a predisposing factor for patients with keratitis.

Absence of Association between Previous Mycoplasma pneumoniae Infection and Subsequent Myasthenia Gravis: A Nationwide Population-Based Matched Cohort Study

Mycoplasma pneumoniae (M. pneumoniae) is not only one of the most common pathogenic bacteria for respiratory infection but also a trigger for many autoimmune diseases. Its infection process shared many similarities with the pathogenesis of myasthenia gravis (MG) at cellular and cytokine levels. Recent case reports demonstrated patients present with MG after M. pneumoniae infection. However, no epidemiological studies ever looked into the association between the two. Our study aimed to investigate the relationship between M. pneumoniae infection and subsequent development of MG. In this population-based retrospective cohort study, the risk of MG was analyzed in patients who were newly diagnosed with M. pneumoniae infection between 2000 and 2013. A total of 2428 M. pneumoniae patients were included and matched with the non-M. pneumoniae control cohort at a 1:4 ratio by age, sex, and index date. Cox proportional hazards regression analysis was applied to analyze the risk of MG development after adjusting for sex, age, and comorbidities, with hazard ratios and 95% confidence intervals. The incidence rates of MG in the non-M. pneumoniae and M. pneumoniae cohorts were 0.96 and 1.97 per 10,000 person-years, respectively. Another case-control study of patients with MG (n = 515) was conducted to analyze the impact of M. pneumoniae on MG occurrence as a sensitivity analysis. The analysis yielded consistent absence of a link between M. pneumoniae and MG. Although previous studies have reported that M. pneumoniae infection and MG may share associated immunologic pathways, we found no statistical significance between M. pneumoniae infection and subsequent development of MG in this study.

The Level of D-Dimer Is Positively Correlated With the Severity of Mycoplasma pneumoniae Pneumonia in Children

Objective

Mycoplasma pneumoniae pneumonia (MPP) is an important disease in children. Studies have demonstrated that the levels of D-dimer are elevated in some children with MPP, especially those with thrombotic complications. However, the potential association between MPP and D-dimer remains unclear. In our study, we sought to explore the relationship between the levels of plasma D-dimer and clinical characteristics of MPP patients.

Methods

Retrospective analysis was conducted on 356 patients who were hospitalized in our hospital for MPP between January 1, 2017, and December 31, 2019. According to the peak value of D-dimer, patients were divided into three groups: the normal group (D-dimer<0.55 mg/L), the mild-moderately elevated group (D-dimer 0.55–5.5 mg/L) and the severely elevated group (D-dimer >5.5 mg/L). The demographic and clinical information, radiological findings, laboratory data, and treatments of patients were compared among different groups.

Results

106 patients were in the normal group, 204 patients were in the mild-moderately elevated group, and 46 patients were in the severely elevated group. More severe clinical and radiographic manifestations, longer length of fever, hospital stay and antibiotic therapy duration, higher incidences of extra-pulmonary complications, refractory MPP (RMPP), severe MPP (SMPP) were found in the elevated group, when compared with the normal group (P<0.01). Meanwhile, we found that the percentage of neutrophil (N%) and CD₈⁺ lymphocyte (CD₈⁺%), C-reactive protein (CRP), lactate dehydrogenase (LDH), interleukin (IL)-6, IL-10, and interferon-gamma (IFN-γ) trended higher with increasing D-dimer, whereas the percentage of lymphocyte (L%) and prealbumin (PAB) trended lower (P<0.01). In addition, the proportions of patients requiring oxygen therapy, glucocorticoid, bronchoscopy, immunoglobulin use, thoracentesis, or ICU admission were significantly higher in the severely elevated group than those in the other two groups (P<0.01). Correlation analysis showed that N%, L%, CRP, LDH, IL-10, length of fever, length of stay, and length of antibiotic therapy had strong correlations with the level of D-dimer.

Conclusions

MPP patients with higher levels of D-dimer had more severe clinical manifestations and needed longer duration of treatment, which might be closely related to the severity of lung inflammation after MP infection.

Infectious causes of Alice in Wonderland syndrome

Alice-in-Wonderland syndrome (AIWS) is a perceptual disorder embracing a spectrum of self-experienced paroxysmal body image illusions including most commonly distortions of shape (metamorphopsia), size (macropsia or micropsia), distance (pelopsia or teleopsia), movement, and color among other visual and somesthetic distortions. Depersonalization, derealization, and auditory hallucinations have also been described. Recent reports suggest that infectious diseases are the predominant etiology for AIWS, especially among children. This article reviews current understanding regarding the association between infection and development of AIWS.

Traditional Chinese Medicine Oral Liquids Combined With Azithromycin for Mycoplasma pneumoniae Pneumonia in Children: A Bayesian Network Meta-Analysis

Background:Mycoplasma pneumoniae pneumonia (MPP) causes flu-like symptoms in children, increasing the burden on the health and education systems. In China, traditional Chinese medicine oral liquids (TCMOLs) combined with azithromycin (TCMOLs + Azithromycin) is commonly used to treat MPP in children. However, TCMOLs with the optimal clinical applicability remain unknown. Here, we evaluated the clinical effectiveness and safety of TCMOLs + Azithromycin in children with MPP.

Methods: We searched PubMed, Embase, Cochrane Library, Ovid, Web of Science, China National Knowledge Infrastructure (CNKI), Wanfang Data Knowledge Service Platform, and VIP information resource integration service platform databases for eligible randomized controlled trials (RCTs) published from database inception to October 2020. Two reviewers independently performed data extraction and risk of bias assessment. After Bayesian random effect modeling and surface under the cumulative ranking curve (SUCRA) scoring, we ranked each intervention. We assessed heterogeneity using multivariate meta-regression for potential modifiers and used the Grading of Recommendations, Assessment, Development, and Evaluation to rate pooled evidence’s certainty.

Results: In the 63 included RCTs with 6,410 children, five different TCMOLs were combined with azithromycin. TCMOLs + Azithromycin had significantly better primary outcomes than did azithromycin alone. Of all TCMOLs, Xiaoer Xiaoji Zhike (XEXJZK)+Azithromycin showed the best effectiveness with respect to the response rate (odds ratio [OR] = 6.5, 95% credible interval [CrI] = 4.3–10; low certainty) and pulmonary rales disappearance time (mean difference [MD] = −2.1, 95% CrI: −2.9 to −1.2; low certainty) with SUCRA 85 and 80%, respectively. Pudilan Xiaoyan + Azithromycin showed the highest effectiveness with respect to cough disappearance time (MD = −2.6, 95% CrI: −3.4 to −1.7; very low certainty) and fever disappearance time (MD = −1.8, 95% CrI: −2.3 to −1.3; very low certainty) with SUCRA 87 and 87%, respectively. The difference in the adverse effects between TCMOLs + Azithromycin and azithromycin alone was nonsignificant.

Conclusion: Of the different TCMOLs, XEXJZK may be the best option to combine with azithromycin to treat children with MPP. However, our results should be interpreted with caution due to the low certainty of evidence. In general, TCMOLs’ safety remains unclear because of a lack of evidence. More high-quality RCTs are needed to further evaluate efficacy and safety of these TCMOLs.

Arthritis associated with Mycoplasma pneumoniae in a pediatric patient: A case report

INTRODUCTION

Mycoplasma pneumoniae (MP) infection in infants is usually overlooked and it might result in important complications if left untreated. MP-induced arthritis is probably the least common extrapulmonary manifestation and frequently leads to delays in the diagnosis.

PATIENT CONCERNS

We report the case of a 2-year-old female child admitted in our clinic for prolonged fever (onset 2 weeks before the admission), for which the general practitioner established the diagnosis of acute pharyngitis and recommended antibiotics. But the fever persisted and the patient was referred to a pediatrician.

DIAGNOSIS

The laboratory tests revealed leukocytosis with neutrophilia, elevated C-reactive protein and liver cytolysis. The blood and urine cultures, as well as the serological hepatitis B and C, toxoplasmosis, Epstein Barr virus, Rubella, Herpes virus, and cytomegalovirus were negative. The chest X-ray established the diagnosis of pneumonia. The fever persisted for approximately 2 weeks after admission. On the 2nd week of admission, the patient began to experience gait difficulties complaining of pain in the right hip and ankle. The cardiology and pneumology consults revealed no pathological findings. The evolution was favorable after the initiation of Levofloxacin and MP infection was detected as we suspected. Moreover, the ultrasound of the hip revealed a mild joint effusion, while the ankle joint appeared to be normal at ultrasound. Thus, we established the diagnosis of hip and ankle arthritis based on the clinical and ultrasound findings.

INTERVENTIONS

Levofloxacin by vein was continued for 5 days, replaced afterwards with clarithromycin orally for 2 weeks.

OUTCOMES

The gait difficulties persisted for approximately 5 months from the initial diagnosis, and improved once the titer of immunoglobulin M anti-MP antibodies lowered considerably. After more than 8 months, the patient was completely asymptomatic and the immunoglobulin M anti-MP was close to the normal range.

CONCLUSION

The awareness of MP-induced arthritis in children represents the cornerstone in preventing diagnostic delays and initiating the proper treatment.

Mycoplasma pneumoniae pneumonia with pulmonary embolism: A study on pediatric cases in Jilin province of China

Mycoplasma is one of the most common pathogens causing community-acquired pneumonia in pediatric patients. In recent years, the number of refractory or severe cases with drug resistance has been gradually increasing and cases that developed embolism after Mycoplasma pneumoniae (M. pneumoniae) infection have been reported. The present study retrospectively analyzed the clinical features, diagnosis and treatment of M. pneumoniae pneumonia (MPP) combined with pulmonary embolism (PE) in a series of 7 cases encountered between January 1st, 2016 to August 1st, 2019 at the Department of Pediatric Intensive Care Unit of The First Hospital of Jilin University (Changchun, China). Combined with relevant Chinese and international studies published during the last two decades, a comprehensive analysis was performed. All of the pediatric patients of the present study had fever, cough and dyspnea respiratory symptoms at onset and the disease progressed rapidly. Thereafter, PE was confirmed by a series of examinations. Pulmonary CT indicated patchy inflammations and significantly elevated D-dimer levels, accompanied by positive anticardiolipin antibodies. Furthermore, a filling defect in the pulmonary artery branch was observed on CT pulmonary angiography (CTPA) examination. In 2 cases, the condition was improved with anti-infection and anticoagulation treatment with low-molecular-weight heparin and warfarin, respectively, and the pulmonary embolism disappeared after 3-4 months. A total of 5 cases, who were not responsive to the drug treatment, underwent surgical resection. During the operation, the local tissues were determined to be infarcted and the pathological diagnosis was consistent with pulmonary infarction. Among the 5 cases, 2 died of Acute Respiratory Distress Syndrome at 3-8 days after the operation. The remaining patients underwent 6-12 months of follow-up and respiratory rehabilitation and their quality of life is now good. In conclusion, compared with healthy individuals, pediatric patients with critical MPP have an elevated risk of embolism. It is necessary to be vigilant regarding whether MMP is combined with PE and perform timely CTPA examination. Early detection, early treatment and surgical intervention (if necessary) may significantly reduce the risk of mortality and disability.

Causes and Clinical Features of Childhood Encephalitis: A Multicenter, Prospective Cohort Study

BACKGROUND

We aimed to determine the contemporary causes, clinical features, and short-term outcome of encephalitis in Australian children.

METHODS

We prospectively identified children (≤14 years of age) admitted with suspected encephalitis at 5 major pediatric hospitals nationally between May 2013 and December 2016 using the Paediatric Active Enhanced Disease Surveillance (PAEDS) Network. A multidisciplinary expert panel reviewed cases and categorized them using published definitions. Confirmed encephalitis cases were categorized into etiologic subgroups.

RESULTS

From 526 cases of suspected encephalitis, 287 children met criteria for confirmed encephalitis: 57% (95% confidence interval [CI], 52%-63%) had infectious causes, 10% enterovirus, 10% parechovirus, 8% bacterial meningoencephalitis, 6% influenza, 6% herpes simplex virus (HSV), and 6% Mycoplasma pneumoniae; 25% (95% CI, 20%-30%) had immune-mediated encephalitis, 18% acute disseminated encephalomyelitis, and 6% anti-N-methyl-d-aspartate receptor encephalitis; and 17% (95% CI, 13%-21%) had an unknown cause. Infectious encephalitis occurred in younger children (median age, 1.7 years [interquartile range {IQR}, 0.1-6.9]) compared with immune-mediated encephalitis (median age, 7.6 years [IQR, 4.6-12.4]). Varicella zoster virus encephalitis was infrequent following high vaccination coverage since 2007. Thirteen children (5%) died: 11 with infectious causes (2 influenza; 2 human herpesvirus 6; 2 group B Streptococcus; 2 Streptococcus pneumoniae; 1 HSV; 1 parechovirus; 1 enterovirus) and 2 with no cause identified. Twenty-seven percent (95% CI, 21%-31%) of children showed moderate to severe neurological sequelae at discharge.

CONCLUSIONS

Epidemic viral infections predominated as causes of childhood encephalitis in Australia. The leading causes include vaccine-preventable diseases. There were significant differences in age, clinical features, and outcome among leading causes. Mortality or short-term neurological morbidity occurred in one-third of cases.

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.

Vogt-Koyanagi-Harada disease presenting secondary to a post-infectious Mycoplasma pneumoniae autoimmune response

Purpose

To report a rare case of Vogt-Koyanagi-Harada disease likely secondary to post-infectious Mycoplasma pneumoniae autoimmune response in a 14-year-old Hispanic female.

Observations

On presentation, visual acuity was 20/400 in the right eye and 20/20 in the left eye. The patient also had bilateral hyperemia, subretinal fluid, and vitreous cell graded at 1+. Fluorescein angiography and indocyanine green chorioangiography showed bilateral peripapillary hypofluorescence consistent with blocking and hyperflourescence consistent with staining. Laboratory testing showed elevated M. pneumoniae IgM and rising IgG antibodies. Topical steroids and oral steroids helped mitigate the systemic disease process and fully restore visual acuity through the 7-week mark.

Conclusions and Importance

The patient had elevated M. pneumoniae IgM and rising IgG antibodies resulting in ocular inflammation likely secondary to an autoimmune response. In this case of post-infectious M. pneumoniae, topical corticosteroids were beneficial in mitigating ocular manifestations initially, although oral steroids were needed and tapered over 6 weeks.

[MERS type II mimicking leukoencephalopathy was suspected to be associated with mycoplasma pneumonia infection]

A 16-year-old male with language disorders, such as motor aphasia or mutism, was hospitalized on day 4 after the onset of fever. Magnetic resonance imaging (MRI) on admission revealed lesions of the corpus callosum and brain white matter. Brain single photon emission computed tomography (99mTc-ethyl cysteinate dimer) on day 7 shows hypoperfusion (with right dominance) of bilateral upper parietal region. His condition improved gradually with symptomatic treatments alone, and he was discharged on day 13. The lesions on the MRI disappeared by day 15. Although this case might have suffered from leukoencephalopathy, clinically mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) type II was suspected from the reversible splenial lesion. Except for the elevation (640 times) of mycoplasma pneumonia antibody titer (particle agglutination) in the serum, the blood tests and cerebrospinal fluid findings showed no significant abnormalities. We then considered this encephalopathy was related to mycoplasma pneumonia infection. Since no symptoms of mycoplasma infection except for neurologic symptoms were observed, indirect mechanism, such as immune-mediated reactions, is suggested to cause encephalopathy in this case.

Neuro-ophthalmological manifestations as complication of an infection with Mycoplasma pneumoniae and subsequent development of disseminated acute encephalitis

El objetivo es describir dos cuadros clínicos neuroftalmológicos en niños por infección sistémica por Mycoplasma pneumoniae (M. pneumoniae). Se presentan los casos de dos niñas de 14 y 12 años que acudieron a urgencias: la primera con oftalmoplejía internuclear y la segunda con pérdida de visión y cefalea. No presentaban otra focalidad neurológica. En la imagen de resonancia magnética se evidenciaron placas hiperintensas en ambas, sugerentes de cuadro desmielinizante. Al mes, los síntomas neuroftalmológicos se resolvieron y las resonancias magnéticas de control fueron normales. El diagnóstico fue encefalitis diseminada aguda secundaria a M. pneumoniae. El diagnóstico se hace por PCR (gold standard) y/o IgM en serología. Es importante pensar en esta posible etiología ante casos sugerentes de enfermedad desmielinizante. Existe controversia sobre el papel de los antibióticos y si se contemplan los corticoides. Como conclusión, M. pneumoniae debe ser diagnóstico diferencial en afectaciones neuroftalmológicas agudas en niños.

Causality Assessment Guidelines for Adverse Events Following Immunization with a Focus on Guillain-Barré Syndrome

South Korea operates a National Vaccine Injury Compensation Program (VICP) for people who experience adverse events following immunization (AEFI). To run this program rationally, it is a prerequisite to confirm whether adverse events were caused by immunization. Guillain–Barré syndrome (GBS), a severe neurological disease with limb pain and muscle weakness as cardinal symptoms, is attracting attention as an AEFI. However, algorithm or guidelines for assessing the causality between vaccination and the incidence of GBS are lacking. We aimed to develop guidelines for causality assessment of GBS as an AEFI and suggest using these guidelines in alignment with the VICP. We systematically searched for other previously published algorithms or guidelines and found a WHO-AEFI guideline used worldwide; however, it only provides general instructions and is not tailored to specific adverse events. We translated and locally adapted the structure of this guideline and then added contents related to GBS. The GBS-specific guideline consists of four steps: case ascertainment of GBS, checklist (including (1) order of incidence, (2) temporal proximity, (3) evidence for other causes and (4) published evidence), an algorithm, and final classification. We listed key information on confirming GBS and whether any other causes of GBS were present. For real world application of the guideline along with the VICP, we collaborated with a panel of neurologists, epidemiologic investigators, and committee members from the VICP. To ensure transparency and a scientific approach, regular updates and collaboration with neurologists are essential. We expect that this guideline will contribute to logical causality assessment and compensation decisions for GBS and will provide the basic structure for causality assessment of other AEFIs.

Vitamin A deficiency is associated with severe Mycoplasma pneumoniae pneumonia in children

Background

Children with vitamin A, D, and E deficiency are susceptible to respiratory infections. However, the correlations between the levels with Mycoplasma pneumoniae pneumonia (MPP) and patient MPP occurrence is still unclear. This study aims to measure and compare the serum levels in severe (sMPP) and non-severe MPP (nsMPP) and to investigate the correlations between their levels and the occurrence of MPP.

Methods

A total of 122 children were enrolled, including 52 sMPP and 70 nsMPP aged 0-15 years old in 2015-2018. The serum levels of vitamins A, D, and E were measured and compared, and two-category logistic regression was used for correlation analysis of vitamins A, D, and E levels with nsMPP and sMPP.

Results

The age was older (7.12 vs. 4.01 y, P=0.002) in the sMPP samples than that in the nsMPP samples. Vitamin A deficiency was present in both the nsMPP and sMPP samples; its level was significantly lower (0.15±0.06 vs. 0.19±0.07, P=0.0193) in the sMPP serum than that in the nsMPP serum. Vitamins E and D in the sMPP samples were significantly lower (vitamin E 7.43±1.55 vs. 8.22±2.22, P=0.0104; vitamin D 23.08±11.0 vs. 32.07±19.2, P=0.0007) than that in the nsMPP group; both sMPP and nsMPP did not show a deficiency of vitamins E and D. Logistic regression analysis revealed that vitamin A deficiency was significantly (OR 0.001, 95% CI: 0.001-0.334, P=0.009) associated with sMPP, and vitamin A supplementation could reduce the incidence of sMPP. In ≥6 y sMPP, the incidence of vitamin A deficiency was 62.5%, while <6 y, 85%, showing a significant difference. Vitamin A level in <6 y sMPP was significantly lower than that in ≥6 y sMPP.

Conclusions

Vitamin A deficiency is associated with sMPP and more likely present in the younger sMPP samples. Therefore, it is important to watch and supplement vitamin A in M. pneumoniae infection patients.

Pediatric Acute-onset Neuropsychiatric Syndrome and Mycoplasma Pneumoniae Infection: A Case Report Analysis with a Metabolomics Approach

Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) is a clinical condition characterized by a sudden and dramatic obsessive-compulsive disorder with a suggested post-infectious immune-mediated etiology. This condition is accompanied by an extensive series of relatively serious neuropsychiatric symptoms. The diagnosis of PANS is made by "exclusion", as the individual PANS symptoms overlap with a multiplicity of psychiatric disorders with the onset in childhood. A number of researchers accumulated evidence to support the hypothesis that PANS was closely associated with a number of infections. In the last decade, metabolomics played an essential role in improving the knowledge of complex biological systems and identifying potential new biomarkers as indicators of pathological progressions or pharmacologic responses to therapy. The metabolome is considered the most predictive phenotype, capable of recognizing epigenetic differences, reflecting more closely the clinical reality at any given moment and thus providing extremely dynamic data. In the present work, the most recent hypothesis and suggested mechanisms of this condition are reviewed and the case of a 10 - year-old girl with PANS is described, before and after clarithromycin treatment. The main results of this case report are discussed from a metabolomics point of view. The alteration of several metabolic pathways concerning the microbial activity highlights the possible role of the microbiome in the development of PANS. Furthermore, different metabolic perturbations at the level of protein biosynthesis, energy and amino acid metabolisms are observed and discussed. Based on our observations, it is believed that metabolomics is a promising technology to unravel the mysteries of PANS in the near future.

Extra-pulmonary diseases related to Mycoplasma pneumoniae in children: recent insights into the pathogenesis

PURPOSE OF REVIEW

Providing an overview on Mycoplasma pneumoniae-related extra-pulmonary diseases (MpEPDs) in children, who represent the preferred target population by those complications, and discussing the main pathogenic mechanisms implicated or potentially involved.

RECENT FINDINGS

Recent evidences supported the fact that M. pneumoniae is more than an extra-cellular pathogen colonizing epithelial cells of the respiratory tract. It is able to penetrate the cell membrane of host cells and to invade the respiratory mucosa, leading to pronounced inflammatory responses and also spreading outside the respiratory system, to some extent. Thus, direct and indirect (immune-mediated) mechanisms have been described in M. pneumoniae infections, but the latter ones have been mainly implicated in MpEPDs, as reviewed here. Recently, interesting insights have been provided, especially as concern neurologic complications, and new potential mechanisms of disease have been emerging for autoimmunity.

SUMMARY

The awareness of the occurrence of MpEPDs, showing very variable clinical expressions, could promote a correct diagnosis and an appropriate treatment. The knowledge of disease mechanisms in MpEPDs is largely incomplete, but recent advances from clinical studies and murine models might promote and direct future research.

Stroke Associated With Recent Mycoplasma Pneumoniae Infection: A Systematic Review of Clinical Features and Presumed Pathophysiological Mechanisms

Introduction: An association between Mycoplasma pneumoniae (MP) infection and stroke has been described, especially in children. However, current knowledge on this rare potential cause of stroke is scant. The purpose of this systematic review of all published cases was to help better understand the relationships between recent MP infection and ischemic stroke on a clinical, radiological and pathophysiological perspective.

Material and Methods: A PubMed and Embase search was performed in September 2018 to identify all published cases of stroke occurring within 4 weeks after MP infection.

Results: Twenty-eight patients with ischemic stroke associated with MP infection were identified. Median age was 8 years (range: neonate to 57). The middle cerebral artery territory was involved in 25 (89%) patients. Fifteen (54%) patients had at least one arterial occlusion. Elevated D-dimer and/or fibrinogen was reported in 8 (29%) patients. Four patients had transient anticardiolipin IgM antibodies. Cerebrospinal fluid analysis showed pleocytosis in 7/20 (35%) patients (median: 19 leucocytes/μL, range: 10 to 63) and MP PCR was positive in 3/8 (38%) patients. The etiological work-up was considered inconclusive in 25 (89%) patients. Three (11%) patients died during follow-up, all of early respiratory deterioration. Neurological functional outcome was good in 22/27 (81%) patients.

Conclusion: The association between MP infection and ischemic stroke in children and young adults is rare. Underlying pathogenesis might include hypercoagulability and vasculitis. Most patients achieve a favorable recovery. Whether MP infection could be a long-term risk factor for stroke by promoting atherosclerosis is uncertain and deserves further investigation.

Reversible splenial lesion syndrome associated with acute Mycoplasma pneumoniae-associated encephalitis: A report of four cases and literature review

Reversible splenial lesion syndrome (RESLES) is a rare clinico-radiological syndrome that is defined as reversible lesions that involve the splenium of the corpus callosum (SCC). RESLES has been reported in patients with a broad spectrum of diseases and conditions, including infections, hypoglycemia and poisoning. The present report described four RESLES cases triggered by Mycoplasma pneumoniae (M. pneumoniae) and discussed the associated diagnostic challenges. Four cases of acute M. pneumoniae-associated encephalitis that displayed RESLES were reviewed. The clinical presentations were nonspecific in these patients. However, magnetic resonance imaging (MRI) revealed consistent lesions in the SCC with a hyperintensity in diffusion-weighted imaging (DWI) and hypointensities in T1WI, which disappeared after a variable lapse. Treatment with azithromycin or combined treatment with immunomodulatory agents if necessary led to a good prognosis. The present findings indicated that radiological diagnosis of RESLES should be considered in patients with M. pneumoniae-associated encephalitis. Furthermore, serum Mycoplasma antibody is important for the diagnosis of M. pneumoniae-associated encephalitis.

Interleukin-17A Exacerbates Disease Severity in BALB/c Mice Susceptible to Lung Infection with Mycoplasma pulmonis

Mycoplasmas are atypical bacteria that disrupt the immune response to promote respiratory tract infections and secondary complications. However, not every immunologic response that protects or damages the host during mycoplasma infection is known. Interleukin-17A (IL-17A) is elevated in individuals infected with mycoplasmas, but how IL-17A and its cellular sources dictate disease outcome remains unclear. Here, IL-17A is hypothesized to worsen disease in individuals susceptible to mycoplasma infection. Thus, monoclonal anti-IL-17A antibodies were given to disease-susceptible BALB/c mice and disease-resistant C57BL/6 mice infected with Mycoplasma pulmonis Neutralizing the function of IL-17A using anti-IL-17A antibodies reduced disease severity during M. pulmonis infection in BALB/c, but not C57BL/6, mice. Neutralizing IL-17A also reduced the incidence of neutrophilic lung lesions during infection in BALB/c mice. Reduced pathology occurred without impacting the bacterial burden, demonstrating that IL-17A is not required for mycoplasma clearance. The main source of IL-17A throughout infection in BALB/c mice was CD4⁺ T cells, and neutralizing IL-17A after infiltration of the lungs by T cells reduced disease severity, identifying the Th17 response as a herald of late mycoplasma pathology in susceptible mice. Neutralizing IL-17A did not further reduce disease during M. pulmonis infection in BALB/c mice depleted of neutrophils, suggesting that IL-17A requires the presence of pulmonary neutrophils to worsen respiratory pathology. IL-17A is a pathological element of murine respiratory mycoplasma infection. Using monoclonal antibodies to neutralize IL-17A could reduce disease severity during mycoplasma infection in humans and domesticated animals.

Mycoplasma pneumoniae: A Potentially Severe Infection

Mycoplasma pneumoniae infections remain one of the most common etiologies of community-acquired pneumonia (CAP). The clinical presentation and manifestations vary widely and can affect all organs of the body. Diagnosis is challenging because there are no constant findings in physical exams or laboratory or radiological assessments that indicate Mycoplasma pneumoniae pneumonia, and specific diagnostic tools are not readily available. Extrapulmonary manifestations and severe pulmonary manifestations can lead to long-term sequelae. The increasing emergence of Mycoplasma pneumoniae that is resistant to macrolides in some areas of the world and increased world travel could add to the difficulty of controlling and treating Mycoplasma pneumoniae infections. We present a concise and up-to-date review of the current knowledge of Mycoplasma pneumoniae pneumonia.

Mycoplasma pneumoniae infection presenting as stroke and meningoencephalitis with aortic and subclavian aneurysms without pulmonary involvement

A 39-year-old Philipino man presented with acute onset fever and headache. Neurological examination was normal except for neck stiffness. There was no history of chest pain, cough or breathlessness. Cerebrospinal fluid (CSF) showed a mild increase in protein with normal sugar and lymphocytic pleocytosis. CSF PCR for herpes simplex and varicella zoster virus was negative. He developed acute right haemiplegia a week after hospitalisation. MRI showed acute infarct in the left centrum semiovale. His angiogram showed aneurysm in the left subclavian artery and aortic arch. The mycoplasma antibody test came positive with very high titres, while rest of the workup was negative. He was treated with azithromycin and his symptoms improved completely.

He was asymptomatic on follow-up after a month. His repeat immunoglobulin G mycoplasma antibody titre showed elevation. Mycoplasma infection is a treatable cause of meningoencephalitis and stroke secondary to vasculitis. Arterial aneurysms are known to occur with mycoplasma infection although rare.

Unilateral brachial plexopathy, a rare complication of Mycoplasma pneumoniae infection

Few reports in the literature describe isolated peripheral neuropathies in relation to Mycoplasma pneumoniae infection without concurrent damage to the central nervous system. To our knowledge only a single case of mononeuritis multiplex with brachial plexus neuropathy coincident with M. pneumoniae has been documented until now. Here we present the first clinical case of lobar M. pneumoniae pneumonia in a 19-year-old female patient, where coincident neurological complications manifested as unilateral brachial plexus neuropathy, affecting axillar and suprascapular nerves. Isolated M. pneumoniae from sputum belonged to P1 type 2 and to MLVA type 3-6-6-2. No mutation associated with macrolide resistance in domain V of the 23S rRNA gene was detected. Serological testing of a GM1 antibody showed positive results, which might support the role of immunologic mechanisms in the pathogenesis of peripheral neuropathies related to M. pneumoniae infection.

Mycoplasmas: Brain invaders?

Mycoplasmas of humans and animals are usually associated with respiratory, autoimmune, genital and joint diseases. Human mycoplasmas have also been known to affect the brain. Severe central nervous system (CNS) diseases, such as encephalitis, have been linked to Mycoplasma pneumoniae and ureaplasma infections. Less well known is the sheep and goat pathogen, Mycoplasma agalactiae, which has been found in large quantities in the brain where it may be responsible for non-purulent encephalitis as well as ataxia in young animals. Experimental intra-mammary infections of sheep with this mycoplasma have resulted in histopathological changes in the CNS. The cattle pathogen, M. bovis, has been reported occasionally in the brains of calves and adult cattle showing a range of histopathological lesions including abscesses and fibrinous meningitis. Two avian pathogens, M. gallisepticum and M. synoviae have been isolated from the brains of poultry showing meningeal vasculitis and encephalitis. There have been no reported detections of two other avian pathogens, M. meleagridis or M. iowae in the CNS. Over the last few decades, mycoplasmas have been isolated from the brains of sea mammals dying in large numbers in the North Sea although it was concluded that their role may be secondary to underlying viral disease. Finally, evidence has been advanced that certain Spiroplasma species may have a role in the development of the transmissible spongiform encephalopathies (TSE). Invasion of the brain by mycoplasmas may be as a result of direct entry following damage to the inner ear as seen with M. bovis or across the blood brain barrier by mechanisms as yet uncertain.

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.

Evaluation of variation in coagulation among children with Mycoplasma pneumoniae pneumonia: a case-control study

Objective

Acute organ embolism in children with Mycoplasma pneumoniae pneumonia (MPP) has been reported, but changes in coagulation are unclear. This study aimed to investigate changes in coagulation in children with MPP.

Methods

A total of 185 children with MMP (cases) and 117 healthy children (controls) were recruited. We measured prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and plasma fibrinogen (FIB) and D-dimer levels.

Results

Plasma FIB (3.39 ± 0.96 g/L vs 2.93 ± 0.6 6g/L, t = 4.50) and D-dimer (326.45 ± 95.62mg/L vs 263.93 ± 103.32mg/L, t=5.36) in MPP children were higher than controls and PT (9.54 ± 4.97S vs 11.48 ± 5.96S, t=3.05) and APTT (31.41 ± 12.01S vs 38.38 ± 11.72S, t=4.95) were shorter than controls. FIB, D-dimer, PT, and APTT were not different between the high IgM-titre and low-titre groups. The areas under the receiver operating characteristic curves in cases and controls for plasma FIB and D-dimer levels were 0.654 (95% confidence interval [CI], 0.593–0.716, P = 0.031) and 0.682 (95% CI, 0.619–0.744, P = 0.032), respectively.

Conclusions

Children with MPP have a higher risk of blood coagulation and thrombosis. Controlling these problems should be considered as soon as possible.

Anti-inflammatory effects of H2S during acute bacterial infection: a review

Hydrogen sulfide (H₂S), previously only considered a toxic environmental air pollutant, is now increasingly recognized as an important signaling molecule able to modulate several cellular pathways in many human tissues. As demonstrated in recent studies, H₂S is produced endogenously in response to different cellular stimuli and plays different roles in controlling a number of physiological responses. The precise role of H₂S in inflammation is still largely unknown. In particular, the role of H₂S in the regulation of the inflammatory response in acute and chronic infections is being actively investigated because of its potential therapeutic use. To study the effect of H₂S as an anti-inflammatory mediator during bacterial infections, we developed an ex vivo model of primary cells and cell lines infected with Mycoplasma. Our data demonstrate a dichotomic effect of H₂S on the NF-kB and Nrf-2 molecular pathways, which were inhibited and stimulated, respectively.

Central retinal artery occlusion and cerebral infarction associated with Mycoplasma pneumonia infection in children

Background

Central retinal artery occlusion (CRAO) is an arterial ischemic stroke, rarely occurred in children accompanied with asymptomatic cerebral infarction and almost never involved in severe pneumonia related to Mycoplasma pneumonia infection.

Case presentation

An 8-year-old boy with severe pneumonia related to Mycoplasma pneumonia infection that developed loss of vision in the left eye on the 14^th day. No light perception and no pupillary reaction to light were found in the left eye. The fundus examination revealed a cherry red spot with severe retinal edema at the macular and peripapillary area, and the optic disc was pale in the left eye but normal in the right eye, suggesting CRAO in the left eye. No obvious neurological symptoms and signs were observed on presentation. Magnetic resonance imaging of the brain showed an abnormal signal of the left lentiform nucleus, caudate nucleus and within the temporal lobe, suggesting an acute cerebral infarction. The analysis of cerebrospinal fluid showed an increasing leukocyte count, but no any pathogenic microorganisms were found. His respiratory symptoms disappeared promptly after therapy, and the patient was discharged after 11 days later, but there was no light in the left eye 2 months after discharge.

Conclusion

M. pneumoniae infection could be developed the risk for cerebral ischemic stroke, including CRAO in children with severe pneumonia. CRAO is a devastating ophthalmologic event leading to a severe impairment of vision. Patients treated within about 6 h of vision loss had a better visual outcome after the onset of vision loss.

Pathogenesis of Mycoplasma pneumoniae: An update

Genus Mycoplasma, belonging to the class Mollicutes, encompasses unique lifeforms comprising of a small genome of 8,00,000 base pairs and the inability to produce a cell wall under any circumstances. Mycoplasma pneumoniae is the most common pathogenic species infecting humans. It is an atypical respiratory bacteria causing community acquired pneumonia (CAP) in children and adults of all ages. Although atypical pneumonia caused by M. pneumoniae can be managed in outpatient settings, complications affecting multiple organ systems can lead to hospitalization in vulnerable population. M. pneumoniae infection has also been associated with chronic lung disease and bronchial asthma. With the advent of molecular methods of diagnosis and genetic, immunological and ultrastructural assays that study infectious disease pathogenesis at subcellular level, newer virulence factors of M. pneumoniae have been recognized by researchers. Structure of the attachment organelle of the organism, that mediates the crucial initial step of cytadherence to respiratory tract epithelium through complex interaction between different adhesins and accessory adhesion proteins, has been decoded. Several subsequent virulence mechanisms like intracellular localization, direct cytotoxicity and activation of the inflammatory cascade through toll-like receptors (TLRs) leading to inflammatory cytokine mediated tissue injury, have also been demonstrated to play an essential role in pathogenesis. The most significant update in the knowledge of pathogenesis has been the discovery of Community-Acquired Respiratory Distress Syndrome toxin (CARDS toxin) of M. pneumoniae and its ability of adenosine diphosphate (ADP) ribosylation and inflammosome activation, thus initiating airway inflammation. Advances have also been made in terms of the different pathways behind the genesis of extrapulmonary complications. This article aims to comprehensively review the recent advances in the knowledge of pathogenesis of this organism, that had remained elusive during the era of serological diagnosis. Elucidation of virulence mechanisms of M. pneumoniae will help researchers to design effective vaccine candidates and newer therapeutic targets against this agent.

Alice in Wonderland syndrome associated with mycoplasma infection

Alice in Wonderland syndrome (AIWS) is a rare condition in which patients report distorted size perception of objects and their own bodies. Although specific causes and pathology have not been elucidated, an association between AIWS and infection has been suggested. To our knowledge, mycoplasma-induced AIWS has not been examined. A girl aged 7 years 11 months presented with fever (temperature, 40°C) and cough. Although the fever disappeared after approximately 10 days, she complained that her mother's face suddenly appeared smaller to her. Subsequently, she complained that objects intermittently appeared smaller than normal. Particle agglutination test indicated elevated serum antibodies against Mycoplasma pneumoniae. The patient was therefore diagnosed the patient with AIWS secondary to mycoplasma infection. Although mycoplasma infection is known to cause various central nervous system symptoms, this is the first report involving AIWS, suggesting that mycoplasma could affect visual function in children.

Mycoplasma pneumoniae triggering the Guillain-Barré syndrome: A case-control study

OBJECTIVE

Guillain-Barré syndrome (GBS) is an acute postinfectious immune-mediated polyneuropathy. Although preceding respiratory tract infections with Mycoplasma pneumoniae have been reported in some cases, the role of M. pneumoniae in the pathogenesis of GBS remains unclear. We here cultured, for the first time, M. pneumoniae from a GBS patient with antibodies against galactocerebroside (GalC), which cross-reacted with the isolate. This case prompted us to unravel the role of M. pneumoniae in GBS in a case-control study.

METHODS

We included 189 adults and 24 children with GBS and compared them to control cohorts for analysis of serum antibodies against M. pneumoniae (n = 479) and GalC (n = 198).

RESULTS

Anti-M. pneumoniae immunoglobulin (Ig) M antibodies were detected in GBS patients and healthy controls in 3% and 0% of adults (p = 0.16) and 21% and 7% of children (p = 0.03), respectively. Anti-GalC antibodies (IgM and/or IgG) were found in 4% of adults and 25% of children with GBS (p = 0.001). Anti-GalC-positive patients showed more-frequent preceding respiratory symptoms, cranial nerve involvement, and a better outcome. Anti-GalC antibodies correlated with anti-M. pneumoniae antibodies (p < 0.001) and cross-reacted with different M. pneumoniae strains. Anti-GalC IgM antibodies were not only found in GBS patients with M. pneumoniae infection, but also in patients without neurological disease (8% vs 9%; p = 0.87), whereas anti-GalC IgG was exclusively found in patients with GBS (9% vs 0%; p = 0.006).

INTERPRETATION

M. pneumoniae infection is associated with GBS, more frequently in children than adults, and elicits anti-GalC antibodies, of which specifically anti-GalC IgG may contribute to the pathogenesis of GBS. Ann Neurol 2016;80:566-580.

Severe childhood Guillain-Barré syndrome associated with Mycoplasma pneumoniae infection: a case series

We report seven children with recent Mycoplasma pneumoniae infection and severe Guillain-Barré syndrome (GBS) that presented to two European medical centres from 1992 to 2012. Severe GBS was defined as the occurrence of respiratory failure, central nervous system (CNS) involvement, or death. Five children had GBS, one Bickerstaff brain stem encephalitis (BBE), and one acute-onset chronic inflammatory demyelinating polyneuropathy (A-CIDP). The five patients with severe GBS were derived from an original cohort of 66 children with GBS. In this cohort, 17 children (26%) had a severe form of GBS and 47% of patients with M. pneumoniae infection presented with severe GBS. Of the seven patients in this case series, five were mechanically ventilated and four had CNS involvement (two were comatose). Most patients presented with non-specific clinical symptoms (nuchal rigidity and ataxia) and showed a rapidly progressive disease course (71%). Antibodies against M. pneumoniae were detected in all patients and were found to be intrathecally synthesised in two cases (GBS and BBE), which proves intrathecal infection. One patient died and only two patients recovered completely. These cases illustrate that M. pneumoniae infection in children can be followed by severe and complicated forms of GBS. Non-specific clinical features of GBS in such patients may predispose a potentially life-threatening delay in diagnosis.

Simulated acute central Mycoplasma infections in rats induce fever, anorexia, body mass stunting and lethargy but spare memory

Despite the documented post-infectious neurological complications of a central nervous system (CNS) Mycoplasma infection in humans, very few studies have investigated the acute inflammatory responses and sickness behaviours induced by CNS Mycoplasma infections. We therefore determined the effect of acute central administration of fibroblast-stimulating lipopeptide-1 (FSL-1), derived from Mycoplasma salivarium, and FAM-20 from a more pathogenic species, namely Mycoplasma pneumoniae, on behavioural and inflammatory responses in rats. Male Sprague-Dawley rats had radiotransmitters implanted, intra-abdominally, to measure body temperature and cage activity continuously. After recovery from surgery, rats were conditioned in a fear conditioning task and then immediately received an intra-cisterna magna (i.c.m.) injection of either: (1) FSL-1 (10 or 100μg/5μl) or its vehicle (phosphate-buffered saline, 5μl), or (2) FAM-20 (10 or 100μg/5μl) or its vehicle (dimethyl sulfoxide, 5μl). Body mass and food intake were measured daily. Memory was assessed seven days after injection using fear conditioning tests. A single, i.c.m. injection of either FSL-1 or FAM-20 induced profound, dose-dependent fever, anorexia, lethargy and body mass stunting in rats. Moreover, rats that received an i.c.m. injection of 100μg/5μl FAM-20 had a significant increase in the concentration of IL-1β in both the hypothalamus and the hippocampus for ~27h after injection. Seven days after FSL-1 or FAM-20 injection, when body mass of rats still was stunted, they maintained their memory for fear of the context and for fear of the tone, despite the increase in hippocampal IL-1β concentration after FAM-20 administration. Thus, acute simulated CNS Mycoplasma infections caused pronounced sickness responses and brain inflammation in rats, but spared fear memory.

Complete occlusion of the right middle cerebral artery associated with Mycoplasma pneumoniae pneumonia

We report a case of a 5-year-old girl who developed left hemiparesis and left facial palsy, 6 days after the initiation of fever and respiratory symptoms due to pneumonia. Chest radiography, conducted upon admission, showed pneumonic infiltration and pleural effusion in the left lung field. Brain magnetic resonance imaging showed acute ischemic infarction in the right middle cerebral artery territory. Brain magnetic resonance angiography and transfemoral cerebral angiography revealed complete occlusion of the right middle cerebral artery. Mycoplasma pneumoniae infection was identified by a 4-fold increase in IgG antibodies to M. pneumoniae between acute and convalescent sera by enzyme-linked immunosorbent assay. Fibrinogen and D-dimer levels were elevated, while laboratory exams in order to identify other predisposing factors of pediatric stroke were all negative. This is the first reported pediatric case in English literature of a M. pneumoniae-associated cerebral infarction involving complete occlusion of the right middle cerebral artery.

Infection with and Carriage of Mycoplasma pneumoniae in Children

“Atypical” pneumonia was described as a distinct and mild form of community-acquired pneumonia (CAP) already before Mycoplasma pneumoniae had been discovered and recognized as its cause. M. pneumoniae is detected in CAP patients most frequently among school-aged children from 5 to 15 years of age, with a decline after adolescence and tapering off in adulthood. Detection rates by polymerase chain reaction (PCR) or serology in children with CAP admitted to the hospital amount 4–39%. Although the infection is generally mild and self-limiting, patients of every age can develop severe or extrapulmonary disease. Recent studies indicate that high rates of healthy children carry M. pneumoniae in the upper respiratory tract and that current diagnostic PCR or serology cannot discriminate between M. pneumoniae infection and carriage. Further, symptoms and radiologic features are not specific for M. pneumoniae infection. Thus, patients may be unnecessarily treated with antimicrobials against M. pneumoniae. Macrolides are the first-line antibiotics for this entity in children younger than 8 years of age. Overall macrolides are extensively used worldwide, and this has led to the emergence of macrolide-resistant M. pneumoniae, which may be associated with severe clinical features and more extrapulmonary complications. This review focuses on the characteristics of M. pneumoniae infections in children, and exemplifies that simple clinical decision rules may help identifying children at high risk for CAP due to M. pneumoniae. This may aid physicians in prescribing appropriate first-line antibiotics, since current diagnostic tests for M. pneumoniae infection are not reliably predictive.