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

Introduction

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

Methods

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

Results

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

Conclusions

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

Kikuchi-Fujimoto Disease Associated With Mycoplasma Pneumoniae Infection

Kikuchi-Fujimoto disease (KFD) is a self-limited disease that is more common in young Asian women. Typical presentations included fever and cervical lymphadenopathy. The etiology of KFD is unknown, and diagnosis is based mainly on lymph node biopsy. KFD has been reported to be associated with Mycoplasma pneumoniae infection. However, the role of antibiotic treatment is unclear. We reported 2 cases of KFD associated with Mycoplasma pneumoniae infection and were successfully treated with a macrolide.

Mycoplasma infection aggravates cardiac involvements in Kawasaki diseases: a retrospective study

Background

Mycoplasma pneumoniae (MP) infection serves as a substantial cofactor in Kawasaki disease (KD) among patients. Although the dominant issue triggering KD has recently focused on MP infection, the complete demonstration of the relationship between MP infection and KD remains elusive. This study endeavors to scrutinize and compare the clinical manifestations and cardiac involvement between MP-triggered KD and non-infection-associated KD.

Method

This retrospective study (2023-039, approved by the Institutional Review Board of West China Second University Hospital of Sichuan University) encompassed 247 consecutive patients diagnosed with KD between June 2017 and December 2022. Patients were categorized into two groups: the MP group (n = 38) and the non-MP group (n = 209). Univariable analysis was utilized to discern differences in clinical features, severity of inflammation, and initial or persistent cardiac complications between the two groups.

Results

The MP group exhibited a more intricate clinical profile compared with the non-MP group, characterized by prolonged hospital stays, a higher incidence of incomplete KD, and elevated comorbidities. In addition, MP infection correlated with severe hematological disorders, coagulation dysfunction, and myocardial injuries. Our findings revealed that MP infection led to prolonged inflammation after initial treatment with intravenous immunoglobulin. Although initial cardiac assessments failed to discern disparities between the two groups, MP infection notably exacerbated coronary artery aneurysms (CAAs), resulting in sustained dilation.

Conclusions

Recognizing MP infection as a significant infectious factor associated with KD is imperative. In patients with KD, MP infection significantly prolongs inflammation and causes hematological disturbances during the initial treatment phase. Moreover, the presence of MP infection exacerbates the progression of CAAs and myocardial injuries during the subacute phase of KD, consequently contributing to the persistence of CAAs.

CC16 drives VLA-2-dependent SPLUNC1 expression

Rationale

CC16 (Club Cell Secretory Protein) is a protein produced by club cells and other non-ciliated epithelial cells within the lungs. CC16 has been shown to protect against the development of obstructive lung diseases and attenuate pulmonary pathogen burden. Despite recent advances in understanding CC16 effects in circulation, the biological mechanisms of CC16 in pulmonary epithelial responses have not been elucidated.

Objectives

We sought to determine if CC16 deficiency impairs epithelial-driven host responses and identify novel receptors expressed within the pulmonary epithelium through which CC16 imparts activity.

Methods

We utilized mass spectrometry and quantitative proteomics to investigate how CC16 deficiency impacts apically secreted pulmonary epithelial proteins. Mouse tracheal epithelial cells (MTECS), human nasal epithelial cells (HNECs) and mice were studied in naïve conditions and after Mp challenge.

Measurements and main results

We identified 8 antimicrobial proteins significantly decreased by CC16-/- MTECS, 6 of which were validated by mRNA expression in Severe Asthma Research Program (SARP) cohorts. Short Palate Lung and Nasal Epithelial Clone 1 (SPLUNC1) was the most differentially expressed protein (66-fold) and was the focus of this study. Using a combination of MTECs and HNECs, we found that CC16 enhances pulmonary epithelial-driven SPLUNC1 expression via signaling through the receptor complex Very Late Antigen-2 (VLA-2) and that rCC16 given to mice enhances pulmonary SPLUNC1 production and decreases Mycoplasma pneumoniae (Mp) burden. Likewise, rSPLUNC1 results in decreased Mp burden in mice lacking CC16 mice. The VLA-2 integrin binding site within rCC16 is necessary for induction of SPLUNC1 and the reduction in Mp burden.

Conclusion

Our findings demonstrate a novel role for CC16 in epithelial-driven host defense by up-regulating antimicrobials and define a novel epithelial receptor for CC16, VLA-2, through which signaling is necessary for enhanced SPLUNC1 production.

The Immunologic Profiles of Kawasaki Disease Triggered by Mycoplasma pneumoniae Infection

OBJECTIVE

We compared the immunologic characteristics of mycoplasma pneumoniae-triggered Kawasaki disease (MP-KD) with Kawasaki disease (KD) not associated with mycoplasma pneumoniae (MP), with mycoplasma pneumoniae-triggered Henoch-Schönlein purpura (MP-HSP), and with healthy controls.

METHODS

Complement levels, cellular and humoral immunity were assessed in KD, in MP-KD, in MP-HSP, and in healthy children.

RESULTS

Of 622 children with KD, 74 had MP-KD. Complement C3 and CD4/CD8 ratio were significantly increased in MP-KD compared to KD. C3, C4, and the ratio of CD4/CD8 in the MP-KD group were higher than those in the MP-HSP group. IgA and CD56 were lower in the MP-KD group than the MP-HSP group.

CONCLUSIONS

Both C3 and polyclonal CD4+ T lymphocytes may be activated in the patients with MP-KD.

Lipschütz Ulcers: Classic Presentation of an Uncommon Condition

We describe the case of a 17-year-old female who presented with the acute onset of painful genital ulcers after experiencing a week of flu-like symptoms. A physical exam revealed two 1 cm necrotic ulcers on the right vulva with an erythematous margin and overlying exudate. A diagnosis of Lipschütz ulcers was made based on the classic signs and symptoms, in addition to ruling out relevant infectious and inflammatory diseases. Our goal in presenting this case is to add to the literature and increase awareness regarding this uncommon condition. The differential diagnosis and workup for genital ulcers can be extensive, but when diagnosed correctly, treatment and reassurance can provide great comfort for the patient.

D-dimer: The Risk Factor of Children's Severe Mycoplasma Pneumoniae Pneumonia

OBJECTIVE

Mycoplasma Pneumoniae (MP) is an important cause of community-acquired pneumonia in children, which can cause serious consequences. There has been some research into predicting Severe Mycoplasma Pneumoniae Pneumonia (SMPP) primarily focused on pre-treatment time by macrolide, pre-hospital course, CRP and LDH et.al. while seldom reporting on concoagulation status. We designed this retrospective study to compare the difference between SMPP and Non-severe MPP (NSMPP) with an attempt to find the risk factors, with a special focus on concoagulation status.

METHOD

We performed a retrospective study of 786 MPP patients who were hospitalized from January 1, 2016 to December 31, 2018, age ranging from 28 days to 18 years old. All patients were divided into SMPP group and NSMPP group. A univariate analysis was conducted between both groups. The factors with statistical differences were included in logistic regression analysis to summarize the predictors of SMPP. Next, the predictive value of each risk factor was calculated from the receiver operating characteristic curve (ROC curve). Patients who had D-dimer records were divided into the elevated D-dimer group (D-dimer > 308ug/L) and the control group (D-dimer ≤ 308ug/L), and the clinical manifestations were compared.

RESULTS

There was no significant difference in gender, age, pre-treatment time by macrolide, the white blood cell counts (WBC), Fibrinogen (FIB), Activated Partial Prothrombin Time (APTT), Prothrombin Time (PT) and Thrombin Time (TT) between SMPP and NSMPP. Compared with NSMPP, the pre-hospital course of SMPP was longer (P < 0.05), the neutrophil ratio (N%), platelet Count (PLT), C-reactive Protein (CRP), Lactate Dehydrogenase (LDH) and D-dimer were significantly higher (P < 0.01). The binary logistic regression analysis showed that the N%, PLT, CRP, LDH and D-dimer were the key predictors for SMPP, the N% > 67%, OR = 3.233, PLT > 445 × 10⁹ /L, OR = 2.589, LDH > 354U/L, OR = 4.335 and D-dimer level > 403 ug/L, OR = 7.316. The D-dimer possessed the best predictive value. The incidence of complications such as pleural effusion, myocardial and liver damage of MPP was higher in the elevated D-dimer group than that in the control group (P < 0.05).

CONCLUSION

The N%, PLT, CRP, LDH and D-dimer were risk factors for SMPP. D-dimer was the best predictor among them. MPP patients with D-dimer > 308ug/L had more complications such as pleural effusion, myocardial and liver damage. More attention should be given in the treatment for this group.

Mycoplasma Pneumoniae Infection and Persistent Wheezing in Young Children: A Retrospective Case-Control Study

BACKGROUND

To investigate the clinical characteristics of children with persistent wheezing (PW) with Mycoplasma pneumoniae (MP) DNA in bronchoalveolar lavage fluid (BALF).

METHODS

This retrospective case-control study included consecutive admitted children under 3 years of age who were diagnosed with PW and had MP DNA detected in BALF. Patients with mycoplasma pneumoniae pneumonia (MPP) and foreign-body aspiration (FBA) were enrolled as controls. The clinical characteristics of the groups were compared.

RESULTS

During the study period, there were 89 patients diagnosed with PW without structural anomalies of the conductive airways, and 30 of these patients (33.7%, 30/89) with MP DNA detected in the BALF were selected as the study group. We included 44 patients with MPP and 44 patients with FBA as controls. Patients with MPP were older and had a higher occurrence of fever and C-reactive protein (CRP) than patients with PW (all P < 0.001). The median MP DNA copy number in patients with MPP was higher than that of patients with PW (P = 0.004). The median level of MP IgG in patients with PW was lower than that of patients with MPP and higher than that of patients with FBA (all P < 0.001). MP DNA copy number positively correlated with age (r = 0.392, P = 0.001) and CRP (r = 0.235, P = 0.048).

CONCLUSIONS

Our study reveals that MP was highly detected in the BALF of PW patients. In addition, young patients with a low load of MP infection showed lower amounts of antibody, and a weak inflammatory response might be associated with PW.

Severe pediatric Mycoplasma pneumonia as the cause of diffuse alveolar hemorrhage requiring veno-venous extracorporeal membrane oxygenation: A case report

BACKGROUND

Diffuse alveolar hemorrhage (DAH) is an acute life-threatening disease often associated with immunocompromised patients and systemic disorders, such as infections, vasculitis, and toxins. Mycoplasma pneumoniae is one of the most common causes of community-acquired pneumonia in children, which rarely causes respiratory failure and fulminant disease; However, a rapid progression may occur in some patients. Mycoplasma pneumonia-associated DAH is rare.

CASE PRESENTATION

We report a case of severe pediatric mycoplasma pneumonia in an immuno-competent child. This patient's condition progressed rapidly, with severe lung lesions associated with pleural effusion, coagulopathy, diffuse alveolar haemorrhage and severe respiratory distress requiring ventilator and intravenous extracorporeal membrane oxygenation (VV-ECMO) support. She was discharged upon successful treatment.

CONCLUSION

Diffuse alveolar hemorrhage associated with Mycoplasma pneumoniae in children is very rare, and clinicians should be aware of the potential rapid onset of the disease. Early detection and diagnosis are very important. The main treatment measures include anti-infection and supportive measures such as mechanical ventilation, but as in our case, success with both prone positioning for more than 10 h per day and VV-ECMO was life-saving.

Infective Endocarditis Secondary to Mycoplasma pneumoniae

Mycoplasma pneumoniae (MP) is a gram-positive bacterium most commonly associated with community-acquired pneumonia in adults. It can also involve other systems of the body. Cardiovascular complications include pericarditis, myocarditis, congestive cardiac failure, and, rarely, infective endocarditis. We report a case of infective endocarditis secondary to MP infection in an adult. We treated our patient with doxycycline, which showed significant improvement.

Mycoplasma pneumoniae Associated Acute Transverse Myelitis: An Atypical Clinical Presentation in an Adolescent Child

We report an atypical case of a 15-year-old pediatric patient diagnosed with Mycoplasma pneumoniae associated acute transverse myelitis (ATM). The patient had no prodromal or pulmonary symptoms that are commonly associated with mycoplasma infection. Yet, the patient exhibited acute bilateral lower extremity paralysis, paresthesia, decreased sensation at the level of T11 and below, bowel and bladder dysfunction, and thrombocytopenia. Magnetic resonance imaging of the spinal cord revealed transverse myelitis from T10 to the end of the conus medullaris. The patient showed only slow clinical improvement despite therapy consisting of azithromycin, high-dose intravenous methylprednisolone, intravenous immunoglobulin, and plasmapheresis. This report calls attention to the importance of early identification of mycoplasma as an underlying cause of ATM and the potential consequences of delayed detection and treatment: more severe neurologic complications, prolonged hospitalization, and unfavorable clinical outcomes.

Mycoplasma pneumoniae and Bronchiolitis Obliterans: How a Common Organism Leads to a Rare Pulmonary Disease in Pediatrics

A rare lung disease, bronchiolitis obliterans (BO) is characterized by airway obstruction and fibrosis of the terminal and respiratory bronchioles. It usually occurs after lung and bone marrow transplants, hematopoietic stem cell transplantation (HSCT), inhalation of toxins, respiratory infections, or in association with several different connective tissue or irritable bowel diseases. When BO is caused by an infection it is referred to as post-infectious bronchiolitis obliterans (PIBO). The prevalence of BO is unknown but has been seen to occur worldwide. The pathophysiology of BO is not fully understood but there is evidence of fibroproliferation leading to abnormal airway remodeling with inflammatory mediators and granulation tissue that narrows the bronchial lumen. Diagnosis of BO is achieved via a combination of clinical manifestations, patient history, pulmonary function test (PFT), radiological imaging, and lung biopsy as the gold standard. Since there is limited literature on pediatric cases with BO and diagnosis may sometimes be challenging, we aim to bring awareness to a pediatric case where PIBO developed after a common pulmonary infection of Mycoplasma pneumoniae.

Mycoplasma Pneumoniae-Induced Rash and Mucositis: A Systematic Review of the Literature

INTRODUCTION

Mycoplasma pneumoniae (MP) is a common respiratory pathogen that can result in community-acquired pneumonia (CAP). Approximately 25% of patients diagnosed with MP experience extrapulmonary manifestations. Mycoplasma-induced rash and mucositis (MIRM) was coined as a unique disease process in 2014. MIRM has prominent mucositis with or without a characteristic vesiculobullous and/or atypical targetoid eruption. Appropriate identification of this disease is important because it has a milder disease course with low rates of sequelae, and lower mortality compared to Stevens-Johnson syndrome, erythema multiforme, and toxic epidermal necrolysis. The objective of this systematic review was to examine the English literature on Mycoplasma Pneumonia-induced rash and mucositis since the establishment of its diagnosis in 2014.

METHODS

The following online databases were used to identify appropriate studies that met the established inclusion and exclusion criteria: Pubmed, Cochrane, MedLine, Health Evidence, EPPI center, Allied Health Evidence. The following MesH search terms were used to further identify articles; "Mycoplasma pneumoniae induced rash and mucositis," "Mycoplasma pneumoniae rash and mucositis," "Mycoplasma pneumoniae rash," "Mycoplasma pneumoniae mucositis," "MIRM," "Mycoplasma induced rash and mucositis," "Mycoplasma rash and mucositis," "Mycoplasma rash," and "Mycoplasma mucositis." Data was extracted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

One hundred and seventy-five records were initially screened, and nineteen studies were included in the review, leading to a total of 27 patients. Patients had a mean age of 16 years old (Range 4 - 46 years old), with the majority being males (74%). Pulmonary symptoms tended to precede extrapulmonary symptoms on an average of 7.8 days. Extrapulmonary symptoms consisted of oral lesions (96.3%) followed by ocular lesions (92.6%) and genital lesions (59.3%). Female patients were more likely to have genital lesions (71.4%) when compared with male patients (55%). Cutaneous rashes occurred in approximately one-half of the patients, which supports the theory that MIRM is a separate clinical entity from SJS and other related skin disorders.Confirmatory testing for MIRM was performed using IgM/IgG Mycoplasma antibody testing or PCR in 19 (66.7%) and 6 (22.2%) patients respectively, although four cases reported the use of both serology and PCR, while five did not report confirmatory testing. Systemic antibiotics were used frequently in treatment 22 patients (77.8%) and 27 (100%) of the patients received various supportive care. Approximately 11 (37%) patients of reported cases used systemic steroids to reduce systemic inflammation. Other systemic treatments were used in six (21.4%) cases, and included intravenous immunoglobulins and cyclosporine A. Only eight patients (22.2%) reported having any lasting sequelae.

CONCLUSION

Mycoplasma-induced rash and mucositis is a recently described extra-pulmonary manifestation of Mycoplasma pneumoniae infections. To the best of the authors' knowledge, this is the first systematic review of the MIRM literature since the introduction of the diagnosis in 2014. The authors hope that this review can serve to better our current understanding and lead to improved identification, work-up, and treatment of this disease. One notable limitation of this study is the relatively small sample size, which is due to the recent introduction of the term.

Thrombosis associated with mycoplasma pneumoniae infection (Review)

Mycoplasma pneumoniae is a common pathogen causing respiratory infections in children and adults. In addition to respiratory diseases, Mycoplasma pneumoniae is also involved in numerous extrapulmonary diseases. Thrombosis is an extrapulmonary manifestation associated with Mycoplasma pneumoniae infection. In recent years, an increasing number of case reports have been published identifying thrombosis secondary to Mycoplasma pneumoniae infection. In the present study, the available relevant literature in English available on PubMed, Medline and Web of Science was consulted. The results of the present study demonstrated that in patients with thrombosis caused by Mycoplasma pneumoniae infection, some of the factors causing thrombosis are transient and some are due to hereditary thrombophilia. Following timely treatment, the majority of patients recovered completely but some patients had a poor prognosis. The present review focuses on the pathogenesis, clinical features, treatment and prognosis of this crucial issue, which contributes toward the understanding of the disease.

A rare case of diffuse alveolar hemorrhage caused by acute mycoplasma pneumoniae pneumonia

Mycoplasma pneumoniae is a common bacterial pathogen that causes atypical community-acquired pneumonia. Illness onset can be gradual and progressive over weeks. Patients typically have cough, pharyngitis, malaise, and tracheobronchitis. Although symptoms are frequently mild, the initial presentation can be severe with numerous complications. We present a case of a 28-year-old male who presented with 1 day of significant hemoptysis. He was intubated for airway protection and underwent bronchoscopy, which showed multiple blood clots in several lung lobes, consistent with diffuse alveolar hemorrhage (DAH). His workup was negative for pulmonary embolism, coagulopathy, and vasculitis. He tested positive for rhinovirus and mycoplasma pneumoniae IgM (negative IgG). He was ultimately discharged home with oral doxycycline to complete a 10-day course. DAH is a rare presentation and life-threatening complication of mycoplasma pneumonia. Although there is a reported association between DAH and rhinovirus, our patient improved with antibiotics making mycoplasma pneumoniae the likely culprit. When encountering hemoptysis or alveolar bleeding, clinicians should have low suspicion for atypical infections and start appropriate antibiotics early in the clinical course.

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.

Clinical features of recurrent Mycoplasma pneumoniae-induced rash and mucositis

BACKGROUND/OBJECTIVES

The characteristics of patients experiencing recurrent Mycoplasma pneumoniae-induced rash and mucositis (MIRM) are not well understood. We aimed to characterize patients with recurrent disease by comparing the demographics, skin and mucosal involvement, seasonality, and treatment to those with single episodes (isolated MIRM).

METHODS

This retrospective case series screened all patients seen by our dermatology inpatient consult service from September 2014 to March 2020. Cases were selected based on laboratory and clinical criteria that confirmed a diagnosis of MIRM.

RESULTS

We identified 13 patients with MIRM: 5 who experienced recurrence (38%) and 8 with isolated, single episodes without recurrence. Mean age was 13.6 years for initial episodes in the recurrent patients compared to 11.7 in patients with isolated episodes. All 5 recurrent MIRM patients were male (compared with 75% of isolated MIRM patients) and predominantly Black (60%, compared with 25%). Most episodes overall (isolated and recurrent) occurred from the months of October to February. Recurrences after initial MIRM episode had less severe skin and mucosal findings, often involving only one mucous membrane, less frequent need for hospital admission, and shorter duration of hospital stay. Prophylactic treatments and treatments beyond supportive care were of unclear value.

CONCLUSIONS

Some characteristics of MIRM differ between patients with recurrent and isolated disease. Clinicians should be aware of the potential for recurrence, which occurred in 38% of our cohort. Although recurrences after initial MIRM episode tended to be less severe, there is still potential for prolonged hospitalizations with recurrent episodes. More evidence is needed regarding effective preventive and treatment regimens in patients with recurrent MIRM.

Immune Thrombocytopenic Purpura: A Sequelae of Mycoplasma pneumoniae Infection

Our patient presented with a mild upper respiratory infection, which quickly developed into atypical pneumonia. Although atypical pneumonia is a common clinical presentation, our case is unique due to the rare hematologic complications associated with the underlying etiology of this atypical pneumonia case. Most cases of atypical pneumonia are simple, but ours developed immune thrombocytopenic purpura (ITP), which is a rare complication associated with an acute Mycoplasma pneumoniae infection (evidenced by positive IgM titers). Although our patient did not develop significant bleeding, our review of the literature demonstrated that ITP associated with M. pneumoniae infection can be fatal. Platelet count should be closely monitored and promptly treated.

Exogenous Hydrogen Sulfide Regulates Mycoplasma pneumoniae Lipid-Associated Membrane Proteins to Induce Expression of Heme Oxygenase-1 and Proinflammatory Cytokines

This study was designed to investigate the effect of exogenous hydrogen sulfide (H2S) on the secretion of Heme oxygenase (HO-1) and proinflammatory cytokines in human mononuclear cell line THP-1 stimulated by lipid-associated membrane proteins (LAMPs) prepared from Mycoplasma pneumoniae (M. pneumoniae) and explore its regulatory mechanism. Cultured cells were stimulated with M. pneumoniae LAMPs after pretreatment with H2S to analyze the production of proinflammatory cytokines and HO-1 by enzyme-linked immunosorbent assay (ELISA) and Western blot. The results showed that THP-1 cells, which were stimulated by LAMPs after pretreatment with H2S, had decreased production of interleukin-6 (IL-6) and interleukin-8 (IL-8) by inhibiting the mitogen-activated protein kinases (MAPKs)/nuclear factor-kappa B (NF-κB) signaling pathway and increased expression of HO-1 by activating the nuclear factor E2-related factor 2 (Nrf2) signaling pathway. Our results indicate that H2S may play an important role in attenuating inflammation induced by M. pneumoniae LAMPs due to its ability to decrease the production of IL-6 and IL-8 and increase the expression of the HO-1. These findings support further studies for possible clinical applications.

[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.

Clinical characteristics of Kawasaki disease complicated with Mycoplasma pneumoniae pneumonia: A retrospective study

This study aimed to investigate the inner linkage and mechanism of Mycoplasma pneumoniae (MP) infection and Kawasaki disease (KD), as well as the risk factors of outcome in this cohort of patients.A retrospective study was performed in 210 patients diagnosed with KD complicated with community acquired pneumonia (CAP) in Children's Hospital, Zhejiang University School of Medicine from January 2014 to December 2017. They were divided into two groups based on MP infection: MP infection group (n = 97) and non-MP infection group (n = 113). We compared the variables of these two groups based on medical records.The MP infection group had higher ESR than the non-MP infection group. During hospitalization, the non-MP infection group had higher levels of WBC during hospital, LDH, PCT, and lower HB when compared to the MP infection group. No differences were found in the hs-CRP level, N%, PLT, ALT, CKMB, and cytokine levels (IL-2, IL-4, IL-6, IL-10, TNF-α, and IFN-γ) between MP and non-MP infection group. Likewise, no difference was found in fever duration or hospital stays between them. Totally 19 patients in the infection group had CAA with a rate of 19.59%; and 27 (23.89%) patients had CAA in the non-MP infection group. Unfortunately, no difference was found in CAA rate between the two groups.MP infection may occur simultaneously in children with Kawasaki disease. KD patients with MP infection tended to occur in older population. MP infection may not increase the risk of CAA, which still needs further large-scaled studies to confirm. Clinicians should be alert to KD patients with high level of ESR. MP should be screened and early treatment with macrolides should be given timely.

Mycoplasma Pneumoniae Induced Rash and Mucositis with Bilateral Otitis Media and Sinusitis

Mycoplasma pneumoniae induced rash and mucositis (MIRM) is a recently identified clinical entity, which describes a subset of extrapulmonary manifestations resulting from Mycoplasma pneumonia infection. Patients present with a wide variety of symptoms including cough, dyspnea, mucositis, conjunctivitis, with or without a variable cutaneous rash. A 24-year-old male presented to the emergency department with worsening dyspnea and new-onset oral, ocular, and genital mucosal lesions. The patient was also found to have bilateral otitis media with tympanic membrane rupture and ethmoid sinusitis upon further evaluation. The patient was originally diagnosed with atypical pneumonia leading to acute hypoxic respiratory failure and was admitted to inpatient care. Work-up revealed positive Mycoplasma pneumoniae immunoglobulin M, and the patient was subsequently diagnosed with MIRM. The patient was provided with supportive care as well as systemic antibiotics, and he fully recovered by day 12 without complication. No standardized treatment guidelines exist for MIRM, and it is universally accepted that supportive management is the mainstay of treatment, consisting of pain management, intravenous hydration, and mucosal care. Although the majority of MIRM patients are generally known to have a full recovery (81%), a variety of ocular, oral, and genital complications have been noted in the literature. Here we present a unique case of MIRM in a 24-year-old male who also had ethmoid sinusitis and bilateral otitis media with unilateral tympanic membrane perforation - two head and neck symptoms not described in previous literature.

Syncope in an Adolescent

Syncope is a common chief complaint in the emergency department (ED); however, the workup of syncope is quite extensive. Likewise, community-acquired pneumonia (CAP) can also be difficult to diagnose due to the wide range of signs and symptoms, and even a larger list of etiologies. Syncope as a presenting symptom of CAP has demonstrated to be a challenging clinical association to make. We present a case of a previously healthy 14-year-old female who presented to the ED for having an episode of syncope at softball practice. Notable aspects of the case-age of the patient and the obscure presentation, as well as laboratory and imaging results-made this case challenging. Thus, obtaining a thorough history from the patient and family and performing a detailed physical examination can really help a clinician lead to an accurate diagnosis.

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.

In vitro susceptibility test of Xiao'er Feire Kechuan Oral Solution to Mycoplasma pneumoniae

The aim of this study was to evaluate the inhibitory effect of antibiotics and Xiao'er Feire Kechuan Oral Solution on Mycoplasma pneumoniae (MP) clinical isolates.Twenty clinical isolates containing A-to-G transition at position 2063 and 10 clinical isolates without mutations in 23S rRNA V regions were randomly selected. The international standard strain FH was chosen as control strain. The minimum inhibitory concentration (MIC) of macrolide, quinolones, tetracycline, and Xiao'er Feire Kechuan Oral Solution to MP clinical isolates were performed using broth microdilution method.In vitro antibiotic susceptibility test of MP clinical isolates showed that MP showed high resistance to macrolide antibiotics (erythromycin and azithromycin); MIC of both were more than 64 μg/mL. The MICs of erythromycin and azithromycin for clinical isolates without mutations in 23S rRNA V regions were ≤0.5 μg/mL. The MICs of tetracycline and levofloxacin for all clinical isolated strains were ≤2.0 μg/mL and ≤1.0 μg/mL, respectively. The MIC of Xiao'er Feire Kechuan Oral Solution was 13.828∼6.914 mg/mL.In vitro, the drug resistance of MP to macrolide antibiotics is higher, MP clinical isolates are sensitive to tetracycline and levofloxacin, and Xiao'er Feire Kechuan Oral Solution also has a certain inhibitory effect on the macrolide-resistant MP.

Pediatric toxic epidermal necrolysis treated successfully with infliximab

Successful management of toxic epidermal necrolysis (TEN) with tumor necrosis factor-α inhibitors has been described in adults. We present a case of a 7-year-old boy with infection-associated TEN, diagnosed by typical clinical and histopathological features, most likely caused by Mycoplasma pneumoniae. Treatment with a single dose of infliximab 5 mg/kg intravenously on day 5 after the onset of symptoms was followed by cessation of all blister formation over 3 days and complete resolution within a week. Sequelae were mild, consisting of postinflammatory hyperpigmentation and dry eyes.

[Value of simultaneous amplification and testing in early diagnosis of Mycoplasma pneumoniae pneumonia and related influencing factors]

OBJECTIVE

To investigate the value of simultaneous amplification and testing (SAT) in the early diagnosis of Mycoplasma pneumoniae pneumonia (MPP) in children and related influencing factors.

METHODS

A total of 526 children with community-acquired pneumonia who were hospitalized between December 2016 and December 2017 were enrolled. Particle agglutination was used to measure serum Mycoplasma pneumoniae (MP) antibody (MP-Ab). The value of SAT in the diagnosis of MPP was evaluated based on these results.

RESULTS

Based on the results of serum MP-Ab measurement, 165 children were diagnosed with MPP. MP-SAT had a sensitivity of 90.9% (150/165), a specificity of 97.9% (368/376), and high accuracy (Youden index=0.89) in the diagnosis of MPP, suggesting that there was good consistency between these two methods (Kappa=0.90). The diagnostic sensitivity of MP-SAT in children with a short course of disease was significantly higher than that in children with a long course of disease (P=0.031). The diagnostic sensitivity of MP-SAT was significantly higher than that of single serum MP-Ab measurement (P=0.018), with poor consistency between these two methods (Kappa=0.039). MP-SAT had good consistency with double serum MP-Ab measurement (Kappa=0.91). The multivariate logistic regression analysis showed that course of disease (≥7 days) and out-of-hospital macrolide treatment were the main factors influencing the results of MP-SAT (P<0.05).

CONCLUSIONS

MP-SAT has high value in the early diagnosis of MPP and can effectively cover the shortage of single serum MP-Ab test in the acute stage and thus provide help for early clinical diagnosis. MP-SAT test should be performed in the early stage of the disease (<7 days) and before the application of macrolide treatment.

[Value of simultaneous amplification and testing in early diagnosis of Mycoplasma pneumoniae pneumonia and related influencing factors]

OBJECTIVE

To investigate the value of simultaneous amplification and testing (SAT) in the early diagnosis of Mycoplasma pneumoniae pneumonia (MPP) in children and related influencing factors.

METHODS

A total of 526 children with community-acquired pneumonia who were hospitalized between December 2016 and December 2017 were enrolled. Particle agglutination was used to measure serum Mycoplasma pneumoniae (MP) antibody (MP-Ab). The value of SAT in the diagnosis of MPP was evaluated based on these results.

RESULTS

Based on the results of serum MP-Ab measurement, 165 children were diagnosed with MPP. MP-SAT had a sensitivity of 90.9% (150/165), a specificity of 97.9% (368/376), and high accuracy (Youden index=0.89) in the diagnosis of MPP, suggesting that there was good consistency between these two methods (Kappa=0.90). The diagnostic sensitivity of MP-SAT in children with a short course of disease was significantly higher than that in children with a long course of disease (P=0.031). The diagnostic sensitivity of MP-SAT was significantly higher than that of single serum MP-Ab measurement (P=0.018), with poor consistency between these two methods (Kappa=0.039). MP-SAT had good consistency with double serum MP-Ab measurement (Kappa=0.91). The multivariate logistic regression analysis showed that course of disease (≥7 days) and out-of-hospital macrolide treatment were the main factors influencing the results of MP-SAT (P<0.05).

CONCLUSIONS

MP-SAT has high value in the early diagnosis of MPP and can effectively cover the shortage of single serum MP-Ab test in the acute stage and thus provide help for early clinical diagnosis. MP-SAT test should be performed in the early stage of the disease (<7 days) and before the application of macrolide treatment.

[Association of drug resistance of Mycoplasma pneumoniae with DNA load and genotypes in children with Mycoplasma pneumoniae pneumonia]

OBJECTIVE

To investigate the association of drug resistance of Mycoplasma pneumoniae (MP) with DNA load and genotypes in children with MP pneumonia.

METHODS

A total of 230 children who were hospitalized and diagnosed with MP pneumonia between January 2012 and December 2016 were enrolled. Throat swabs were collected from the 230 children, and a rapid drug sensitivity assay was used to determine the sensitivity of clinical isolates of MP to nine commonly used antibacterial agents. Quantitative real-time PCR was used to measure MP-DNA load in throat swabs. PCR sequencing was used to determine the genotype of 2063 locus of the MP 23S rRNA V domain.

RESULTS

Of the 230 children, 86 (37.4%) had genotype A in 2063 locus, 134 (58.3%) had genotype G, 8 (3.5%) had genotype C, and 2 (0.9%) had genotype T. Mutant strains (genotype G+C+T) had a significantly higher MP-DNA load than wild-type strains (genotype A) (P<0.05). The strains resistant to erythromycin, azithromycin, clarithromycin, and clindamycin had a significantly higher MP-DNA load than non-resistant strains (P<0.05). MP had a high drug resistance rate to macrolide antibiotics. More than 60% of the cases with resistance to macrolides were found to have A2063G mutations. MP was rarely resistant to quinolones (less than 2%).

CONCLUSIONS

Mutations in 2063 locus of the MP 23S rRNA V domain may result in the resistance of MP to macrolides and the change in DNA load and can be used as a basis for selecting drugs for MP.

Effect of Qingfei Mixture () on pediatric mycoplasma pneumoniae pneumonia with phlegm heat obstructing Fei (Lung) syndrome

OBJECTIVE

To explore the effect and mechanism of Qingfei Mixture (), a Chinese medicine, in treating mycoplasma pneumonia (MP) in MP patients and rat model METHODS: A total of 46 MP children with phlegm heat obstructing Fei (Lung) syndrome were randomly assigned to two groups by the method of random number table, with 23 children in each group. The control group was treated with intravenous infusion of azithromycin; the treatment group received intravenous infusion of azithromycin and oral administration of Qingfei Mixture. The treatment course was 7 days. Major symptoms and minor symptoms were observed and scored before and after treatments. A rat model of MP was also established. A total of 120 wistar rats were randomly divided into 5 groups: a normal group, infection group, Qingfei Mixture treatment group, azithromycin treatment group, and Qingfei Mixture + azithromycin treatment group. Each group contained 24 rats, from which every 6 were euthanatized 1, 3, 7 and 14 days after infection. MP DNA in pulmonary tissue homogenates was detected using real-time fluorescence quantitative polymerase chain reaction. Pathology was assessed after hematoxylin (HE) staining and lung tissue pathology scores were determined in pulmonary tissue. Transmission electron microscopic detection and electronic image analysis were performed on lung tissue 3 days after infection. Interleukin (IL)-17 was detected in serum using enzymelinked immunosorbent assay (ELISA) 7 days after infection.

RESULTS

In the clinical study, both control and the treatment group showed improved results on removing symptoms of phlegm heat syndrome compared to the control group (P<0.05). In animal experiments, On the 7th day after MP infection, as detected by electron microscopy, the pulmonary capillary basement membranes of the azithromycin + Qingfei Mixture treatment group were much thinner than those of the azithromycin or Qingfei mixture treatment groups (P<0.05). The level of serum IL-17 in the azithromycin + Qingfei Mixture treatment group was lower than that in the azithromycin or Qingfei Mixture groups (P<0.01).

CONCLUSION

Both Qingfei Mixture and azithromycin have therapeutic effects on mycoplasma pneumoniae pneumonia, but the combination of both agents had the greatest effect.

[Effect of annexin A2 on EGFR/NF-κB signal transduction and mucin expression in human airway epithelial cells treated with Mycoplasma pneumoniae]

OBJECTIVE

To investigate the effect of annexin A2 (AnxA2) on epithelial growth factor receptor (EGFR)/nuclear factor-κB (NF-κB) signal transduction and mucin expression in human airway epithelial H292 cells treated with Mycoplasma pneumoniae (MP).

METHODS

H292 cells were divided into control group, MP group, NC-siRNA+MP group, and AnxA2 siRNA+MP group. The cells in the MP group were incubated with 5 μg/mL MP antigen for 2 hours. The cells in the NC-siRNA+MP and AnxA2 siRNA+MP groups were transfected with NC-siRNA and AnxA2 siRNA for 24 hours, followed by MP antigen stimulation for 2 hours. The MTT method was used to measure cell viability; quantitative real-time PCR was used to measure the mRNA expression of AnxA2; Western blot was used to measure the protein expression of AnxA2, phosphorylated EGFR (p-EGFR), and phosphorylated p65 NF-κB (p-p65 NF-κB); ELISA was used to measure the secretion of mucin 5AC (MUC5AC) and mucin 5B (MUC5B).

RESULTS

The MP and NC-siRNA+MP groups had lower cell viability than the control group (P<0.05). The AnxA2 siRNA+MP group had higher cell viability than the MP and NC-siRNA+MP groups and lower cell viability than the control group (P<0.05). The MP and NC-siRNA+MP groups had significantly higher mRNA and protein expression of AnxA2 than the AnxA2 siRNA+MP group (P<0.05). Compared with the control group, the MP and NC-siRNA+MP groups had significant increases in the protein expression of p-EGFR, p-p65 NF-κB, MUC5AC, and MUC5B (P<0.05); the AnxA2 siRNA+MP group had lower protein expression than the MP and NC-siRNA+MP groups, but higher protein expression than the control group (P<0.05).

CONCLUSIONS

AnxA2 is involved in the airway lesion induced by MP antigen via mediating EGFR/NF-κB signaling activation and mucin expression in human airway epithelial cells.

Extensive and Progressive Cerebral Infarction after Mycoplasma pneumoniae Infection

Acute cerebral infarctions are rare in children, however they can occur as a complication of a Mycoplasma pneumoniae (MP) infection due to direct invasion, vasculitis, or a hypercoagulable state. We report on the case of a 5-year-old boy who had an extensive stroke in multiple cerebrovascular territories 10 days after the diagnosis of MP infection. Based on the suspicion that the cerebral infarction was associated with a macrolide-resistant MP infection, the patient was treated with levofloxacin, methyl-prednisolone, intravenous immunoglobulin, and enoxaparin. Despite this medical management, cerebral vascular narrowing progressed and a decompressive craniectomy became necessary for the patient’s survival. According to laboratory tests, brain magnetic resonance imaging, and clinical manifestations, the cerebral infarction in this case appeared to be due to the combined effects of hypercoagulability and cytokine-induced vascular inflammation.

[Association of T lymphocyte subsets and allergens with Mycoplasma pneumoniae infection complicated by wheezing in infants and young children]

OBJECTIVE

To investigate the percentage of T lymphocyte subsets and allergen screening results in infants and young children with Mycoplasma pneumoniae (MP) infection complicated by wheezing.

METHODS

Flow cytometry was used to measure the percentage of peripheral blood T cell subsets in 354 infants and young children with MP infection complicated by wheezing (MP wheezing group), 336 infants and young children with MP infection but without wheezing (MP non-wheezing group), and 277 children with recurrent wheezing (recurrent wheezing group). Allergen screening was also performed for these children.

RESULTS

Both the MP wheezing group and recurrent wheezing group had significantly lower percentages of CD3⁺ and CD3⁺CD8⁺ lymphocytes than the MP non-wheezing group (p<0.05). The MP groups with or without wheezing had a significantly higher percentage of CD3⁺CD4⁺ lymphocytes than the recurrent wheezing group (p<0.05). Both the MP wheezing group and recurrent wheezing group had significantly higher percentages of CD3^-CD19⁺ and CD19⁺CD23⁺ lymphocytes than the MP non-wheezing group (p<0.05), and the recurrent wheezing group had the highest percentages (p<0.05). The overall positive rate of food allergens was significantly higher than that of inhaled allergens (30.3% vs 14.7%; p<0.05). The positive rates of food and inhaled allergens in the recurrent wheezing group and MP wheezing group were significantly higher than in the MP non-wheezing group (p<0.05), and the recurrent wheezing group had the highest rates.

CONCLUSIONS

Imbalance of T lymphocyte subsets and allergic constitution play important roles in the pathogenesis of MP infection complicated by wheezing in infants and young children.

[Risk factors for recurrent wheezing in infants and young children suffering from dust mite allergy after their first wheezing]

OBJECTIVE

To investigate the risk factors for recurrent wheezing in infants and young children suffering from dust mite allergy after their first wheezing.

METHODS

A total of 1 236 infants and young children who experienced a first wheezing episode and were hospitalized between August 2014 and February 2015 were enrolled, among whom 387 were allergic to dust mites. These infants and young children were followed up to 1 year after discharge. A total of 67 infants and young children who experienced 3 or more recurrent wheezing episodes within 1 year were enrolled as the recurrent wheezing group, while 84 infants and young children who did not experience recurrent wheezing during follow-up were enrolled as the control group. Univariate analysis and multivariate logistic stepwise regression analysis were performed to investigate the risk factors for recurrent wheezing in these patients.

RESULTS

The univariate analysis showed that the age on admission, wheezing time before admission, Mycoplasma pneumoniae infection rate, and influenza virus infection rate were associated with recurrent wheezing. The multivariate logistic stepwise regression analysis showed that the older age on admission (OR=2.21, P=0.04) and Mycoplasma pneumoniae infection (OR=3.54, P=0.001) were independent risk factors for recurrent wheezing.

CONCLUSIONS

Infants and young children who are allergic to dust mites, especially young children, have a significantly increased risk of recurrent wheezing if they are complicated by Mycoplasma pneumoniae infection during the first wheezing episode.

[Risk factors for recurrent wheezing in infants and young children suffering from dust mite allergy after their first wheezing]

OBJECTIVE

To investigate the risk factors for recurrent wheezing in infants and young children suffering from dust mite allergy after their first wheezing.

METHODS

A total of 1 236 infants and young children who experienced a first wheezing episode and were hospitalized between August 2014 and February 2015 were enrolled, among whom 387 were allergic to dust mites. These infants and young children were followed up to 1 year after discharge. A total of 67 infants and young children who experienced 3 or more recurrent wheezing episodes within 1 year were enrolled as the recurrent wheezing group, while 84 infants and young children who did not experience recurrent wheezing during follow-up were enrolled as the control group. Univariate analysis and multivariate logistic stepwise regression analysis were performed to investigate the risk factors for recurrent wheezing in these patients.

RESULTS

The univariate analysis showed that the age on admission, wheezing time before admission, Mycoplasma pneumoniae infection rate, and influenza virus infection rate were associated with recurrent wheezing. The multivariate logistic stepwise regression analysis showed that the older age on admission (OR=2.21, P=0.04) and Mycoplasma pneumoniae infection (OR=3.54, P=0.001) were independent risk factors for recurrent wheezing.

CONCLUSIONS

Infants and young children who are allergic to dust mites, especially young children, have a significantly increased risk of recurrent wheezing if they are complicated by Mycoplasma pneumoniae infection during the first wheezing episode.

[Application of Mycoplasma pneumoniae antibody and load index in the diagnosis of Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.

METHODS

A total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.

RESULTS

The cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).

CONCLUSIONS

MPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.

[Application of Mycoplasma pneumoniae antibody and load index in the diagnosis of Mycoplasma pneumoniae pneumonia in children]

OBJECTIVE

To study the role of Mycoplasma pneumoniae (MP) load and antibody measurements in the diagnosis of MP pneumonia.

METHODS

A total of 115 children with MP pneumonia and 400 healthy children were enrolled. The MP load and total antibody level were measured at different stages, and the MP load index (MPLI) was calculated.

RESULTS

The cut-off value of MPLI for MP infection was 6.12. MPLI and total antibody titer increased during the course of the disease, while MP-DNA decreased rapidly. Within the same time of blood collection, the group with a higher MP load had a significantly higher total antibody titer than the group with a lower MP load (P<0.05). Within 2 weeks of the course of the disease, the negative antibody group had a significantly higher MPLI than the positive antibody group (P<0.05).

CONCLUSIONS

MPLI provides a standardized quantitative value of MP-DNA and plays an important role in the early diagnosis of MP infection.

[Distribution characteristics of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila in hospitalized children with acute respiratory tract infection: an analysis of 13 198 cases]

OBJECTIVE

To investigate the distribution characteristics of Mycoplasma pneumoniae (MP), Chlamydia pneumoniae (CP), and Legionella pneumophila (LP) in hospitalized children with acute respiratory tract infection (ARTI).

METHODS

A total of 13 198 hospitalized children with ARTI were enrolled as study subjects. Whole blood and urine were collected. The passive agglutination was used to detect serum MP-IgM, ELISA was used to detect serum CP-IgM, and immunochromatography was performed to detect urinary LP antigen.

RESULTS

Among the 13 198 hospitalized ARTI children, the detection rates of MP, CP, and LP were 25.31%, 12.74% and 3.27%, suggesting that MP had the highest detection rate (P<0.0125). The detection rates of MP in 2013 and 2014 were significantly higher than that in 2012 (P<0.0125). CP had the highest detection rate in 2013, and LP had the highest detection rate in 2014 (P<0.0125). These three pathogens were detected all around the year, and MP had the highest detection rate in all seasons (P<0.0125). The detection rate of mixed infection with three pathogens was 4.35%, and mixed infection with MP and CP was the most common (P<0.0071). Among the children in different age groups, the patients aged 5-16 years showed the highest overall detection rate of three pathogens (P<0.0071). Among the children with different types of ARTI, the children with bronchopneumonia showed the highest overall detection rate of three pathogens (P<0.0045).

CONCLUSIONS

MP, CP, and LP, particularly MP, are important pathogens for children with ARTI in the local area. LP infection tends to increase year by year and should be taken seriously in clinical practice.

[Distribution characteristics of Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila in hospitalized children with acute respiratory tract infection: an analysis of 13 198 cases]

OBJECTIVE

To investigate the distribution characteristics of Mycoplasma pneumoniae (MP), Chlamydia pneumoniae (CP), and Legionella pneumophila (LP) in hospitalized children with acute respiratory tract infection (ARTI).

METHODS

A total of 13 198 hospitalized children with ARTI were enrolled as study subjects. Whole blood and urine were collected. The passive agglutination was used to detect serum MP-IgM, ELISA was used to detect serum CP-IgM, and immunochromatography was performed to detect urinary LP antigen.

RESULTS

Among the 13 198 hospitalized ARTI children, the detection rates of MP, CP, and LP were 25.31%, 12.74% and 3.27%, suggesting that MP had the highest detection rate (P<0.0125). The detection rates of MP in 2013 and 2014 were significantly higher than that in 2012 (P<0.0125). CP had the highest detection rate in 2013, and LP had the highest detection rate in 2014 (P<0.0125). These three pathogens were detected all around the year, and MP had the highest detection rate in all seasons (P<0.0125). The detection rate of mixed infection with three pathogens was 4.35%, and mixed infection with MP and CP was the most common (P<0.0071). Among the children in different age groups, the patients aged 5-16 years showed the highest overall detection rate of three pathogens (P<0.0071). Among the children with different types of ARTI, the children with bronchopneumonia showed the highest overall detection rate of three pathogens (P<0.0045).

CONCLUSIONS

MP, CP, and LP, particularly MP, are important pathogens for children with ARTI in the local area. LP infection tends to increase year by year and should be taken seriously in clinical practice.

Atopy: a risk factor of refractory mycoplasma pneumoniae pneumonia?

OBJECTIVE

To investigate the relationship of pathogen DNA copies with clinic and laboratory features among children with Mycoplasma pneumoniae (MP) pneumonia.

METHODS

A total of 95 enrolled children with MP pneumonia were assigned into the high-MP-load group (>10⁶ /mL) and the low-MP-load group (≤10⁶ /mL) according to MP-DNA copies in bronchoalveolar lavage fluid (BALF). Clinical characteristics and any allergy history were collected. Aeroallergens and food allergens were detected with a skin test. Serum IgE and eosinophil cationic protein (ECP) were assessed using enzyme immunoassay. BALF levels of IL-4, IFN-γ, IL-8 and TNF-α were assessed by ELISA.

RESULTS

Compared with the low-MP-load group, 72.7% in the high-MP-load group developed refractory MP pneumonia who failed to respond to at least 1-week treatment with macrolides (72.7% vs 41.9%, P = 0.005). More children in the high-load group than those in the low-load group presented with extrapulmonary manifestations, lung consolidation, pleural effusion and atopic conditions including any allergy history, positive findings of aeroallergen test and increased serum IgE and ECP (P < 0.05). A significant higher BALF IL-4 level was seen in the high-load group versus the low-load group (23.00 ± 11.24 vs 14.68 ± 7.12; pg/mL; P < 0.01). There were no significant differences in BALF levels of IFN-γ, IL-8 and TNF-α between the two groups (P > 0.05).

CONCLUSION

Atopy may be a risk factor for the presence and severity of refractory MP pneumonia due to the high pathogen load in airway.

Characterization of macrolide resistance of Mycoplasma pneumoniae in children in Shenzhen, China

Macrolide-resistant Mycoplasma pneumoniae (MR-M. pneumoniae) was isolated from clinical specimens in Shenzhen, China from November 2010 to July 2011. A comparative study was conducted to determine whether macrolides are effective in treating patients infected with MR-M. pneumoniae. Of 57 M. pneumoniae strains, 36 harbored point mutations on A2063G in the 23S ribosomal RNA gene. A total of 36 (63%) strains were classified as MR-M. pneumonia and 21 (37%) as macrolide-susceptible M. pneumoniae (MS-M. pneumoniae). The clinical courses of MR-M. pneumoniae-infected patients (MR patients) treated with macrolides were compared with those of MS-M. pneumoniae-infected patients (MS patients). The patient demographics (sex, age), most laboratory findings, and diagnosis did not show significant differences between the two groups. The MR patients had higher mean total febrile days compared with MS patients (6.56 ± 6.17 days vs. 3.57 ± 3.80 days, P = 0.05). The MR patients were more likely to be have levels of high-sensitivity C-reactive protein than MS patients (42% (15/36) vs. 14% (3/21), P = 0.03). Although the febrile period was prolonged in MR patients treated with macrolides, the fever resolved even when the initial prescription was unchanged. Therefore, these results suggest that macrolides are less effective in MR patients than in MS patients.

Two separated thrombi in deep veins associated with pulmonary embolism after Mycoplasma pneumoniae infection: a case in adolescent female

Mycoplasma pneumoniae is a common pathogen for respiratory infection in children, and vascular complication is one of the rarest extrapulmonary complications but with serious consequences. We report a twelve-year-old Chinese female presenting with fever, dry cough, and chest pain aggravated by respiration. She was diagnosed pneumonia due to Mycoplasma pneumoniae and treated with Azithromycin until unexpected tachypnea and swelling in the right lower limb happened. Then ultrasonic examination had revealed two separated thrombi in deep veins before pulmonary embolism was found. Finally she was cured by anticoagulation and immunosuppressive therapy. Though the mechanism of thrombosis after Mycoplasma pneumoniae infection remains unknown, the positive finding in anticardiolipin antibody as well as multi-site thromboses gives a strong hint to immune modulation. Thrombosis should be considered for those who have significantly increased C-reactive protein and positive anticardiolipin antibody after Mycoplasma pneumoniae infection. To our knowledge, this is the first report describing two unattached thrombi in deep veins associated with pulmonary embolism after Mycoplasma pneumonia infection.

PCR versus serology for diagnosing Mycoplasma pneumoniae infection: a systematic review & meta-analysis

BACKGROUND & OBJECTIVES

Diagnosis for Mycoplasma pneumoniae usually relies on serological tests. PCR technology has some advantages but also limitations. The optimal selection for these tests still needs discussion. This paper reviews the overall diagnostic accuracy of PCR versus serological assays for diagnosis of M. pneumoniae infections and to identify factors associated with heterogeneity of results.

METHODS

MEDLINE and Embase databases were searched. Articles meeting the selection criteria were retrieved for data collection and analysis. Studies were assessed for methodological quality using QUADAS. Hierarchial summary receiver operating characteristic (HSROC) model was used to estimate summary ROC curve.

RESULTS

Initial meta-analysis showed a summary estimate of sensitivity (SEN) 0.62 (95% CI, 0.45-0.76), and specificity (SPE) 0.96 (95% CI, 0.93-0.98). Subgroup analyses were performed to identify factors associated with heterogeneity. For different gene targets, reference standards, subjects (children or adults) and different PCR types, these aspects can generate results of heterogeneity. The 16s rDNA target and adult subjects and real-time PCR may have better test results for PCR.

INTERPRETATION & CONCLUSIONS

Commercial PCR tests generated consistent results with high specificity but a lower and more variable sensitivity. The findings suggest commercial PCR tests having superiorities in diagnosing M. pneumoniae infections but still cannot replace serology. PCR plus serology could be good screening tests for reliable and accurate diagnosis of M. pneumoniae.

Atypical pathogens as etiologic agents in hospitalized patients with community-acquired pneumonia in Korea: a prospective multi-center study

Local epidemiologic data on the etiologies of patients hospitalized with community-acquired pneumonia (CAP) is needed to develop guidelines for clinical practice. This study was conducted prospectively to determine the proportion of atypical bacterial pathogens in adults patients hospitalized with CAP in Korea between October 2001 and December 2002. Microbiological diagnosis was determined by serology for antibodies to Mycoplasma pneumoniae, Chlamydia pneumoniae, and Legionella pneumophila. Nucleic acid of M. pneumoniae and C. pneumoniae in respiratory samples and Legionella antigen in urine samples were detected. The study population consisted of 126 patients (71 males, 55 females), averaging 54.6 yr (SD+/-17.8), whose paired sera were available. An etiologic diagnosis for atypical pathogens was made in 18 patients (14.3%): C. pneumoniae 9 (7.1%), M. pneumoniae 8 (6.3%), and L. pneumophila 3 patients (2.4%). Streptococcus preumoniae and other typical pathogens were isolated from 36 patients (28.6%). Of 126 patients, 16 (12.7%) were admitted to intensive care unit and atypical pathogens were identified in 5 patients (31.3%). Initial clinical features of patients with pneumonia due to atypical, typical or undetermined pathogens were indistinguishable. We conclude that atypical pathogens should be seriously considered in hospitalized patients with CAP, when initiating empiric treatment in Korea.