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Objective: Mycoplasma pneumoniae ( M. pneumoniae ), an extracellular pathogen lacking a cell wall, causes respiratory infection in adults and children and has been implicated in asthma exacerbation; immunoglobulin (Ig) E may be involved in these exacerbations. Specific IgM and IgG immune response to M. pneumoniae has been reported, but less is known about IgE M. pneumoniae antibody (Ab) responses in asthma. Previous studies in our laboratory demonstrated that asthmatic children have increased IgM M. pneumoniae levels, but not IgE. Thus, we sought to investigate whether past M. pneumoniae infection triggers production of M. pneumoniae -specific IgE Abs in adult subjects with/without asthma., Methods: M. pneumoniae - IgE and -IgM Ab responses were studied in adult asthmatic (N=22) and non-asthmatic (N=22) subjects (ELISA). Data are reported as antibody index. Threshold detection levels: IgE, IgM: 0.2, 0.9, respectively., Results: M. pneumoniae -IgE Ab levels were low and below the threshold of detection in both asthmatic and non-asthmatics (0.002 ± 0.008 vs. 0.02 ± 0.03; P =0.021). However, specific-IgM levels were slightly higher in non-asthmatics compared with asthmatics (0.96 ± 0.37 vs. 0.79 ± 0.31; P =0.054). M. pneumoniae -IgM Ab positivity was similar in both groups ( P =1.0)., Conclusion: IgM M. pneumoniae Abs may play an important role in non-asthma and persist for months after acute infection. IgE M. pneumoniae Abs may play a less important role in both groups., (© 2021 by the Association of Clinical Scientists, Inc.)

Objectives: Refractory mycoplasma pneumoniae pneumonia (RMPP) in children has been increasing worldwide. In this study, we conducted a meta-analysis to generate large-scale evidence on the risk factors of RMPP to provide suggestions on prevention and controlling for children., Methods: Web of Science, PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure, and Wanfang (Chinese) were searched to identify relevant articles. All analyses were performed using Stata 14.0., Results: We conducted a meta-analysis of 15 separate studies. Fever for more than 10 days (odds ratio [OR] 3.965, 95% confidence interval [CI] 2.109-7.456), pleural effusion (OR 6.922, 95% CI 2.058-23.282), extra-pulmonary complications (OR 17.762, 95% CI 11.146-28.305), pulmonary X-ray consolidation ≥2/3 (OR 8.245, 95% CI 1.990-34.153), CRP >40 mg/L (OR 4.975, 95% CI 2.116-11.697) were significantly related to the risk of RMPP. We did not find an association between male sex (OR 0.808, 95% CI 0.548-1.189), LDH >410IU/L (OR 1.033, 95% CI 0.979-1.091) and the risk of RMPP., Conclusions: Fever for more than 10 days, pleural effusion, extra-pulmonary complications, pulmonary X-ray consolidation≥ 2/3 and CRP >40 mg/L are risk factors for early evaluation of RMPP., Competing Interests: The authors have no funding and they declare that they have no conflict of interest., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Background: Acute chest syndromes (ACS) may be associated with upper respiratory tract infections, but the epidemiology of viral and intracellular respiratory pathogens in children with sickle cell disease (SCD) is not precisely known. The aim of this study was to describe the epidemiology of viral and intracellular respiratory pathogens in children with SCD presenting with fever and/or ACS., Materials and Methods: An observational, prospective, single-centre cohort study with nested case-control analysis was conducted on children with SCD admitted from October 2016 to October 2017 for fever and/or ACS to the paediatric department of Robert Debré university hospital, Paris, France. They were screened for 20 respiratory pathogens by a multiplex PCR in the nasopharynx (FilmArray)., Results: We included 101 children. M/F sex ratio of 0.45. The median age was 3.2 years (IQR: 1.4-8.2). At least one pathogen was isolated in 67 patients (67%). The most frequent viruses were as follows: rhinovirus (n=33), adenovirus (n=14), respiratory syncytial virus (n=13) and parainfluenza viruses (n=11). Mycoplasma pneumoniae was detected in one case. Twenty-three (23%) presented with or developed ACS. A nested case-control analysis was performed, after pairing ACS with non-ACS children for age and inclusion period. There was no statistical association between any viral detection or multiple viral infection, and ACS (p=0.51) even though parainfluenza viruses were twice as common in ACS., Conclusions: Viral detection in febrile children with SCD is frequent, but its association with ACS was not demonstrated. In this study, M. pneumoniae was rare in young children with SCD experiencing ACS., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The incidence of necrotizing pneumonia (NP) caused by Mycoplasma pneumoniae (MP) is increasing. We analyzed the clinical characteristics and the risk factors for NP caused by MP., Methods: A retrospective observational study was conducted in 37 patients with NP caused by MP (NP group) and 74 patients diagnosed with lobar M. pneumoniae pneumonia with no necrosis (control group) who were admitted to our hospital between January 2013 and December 2017. The clinical manifestations, laboratory data, imaging findings, treatments and outcomes were analyzed., Results: The proportion of females, the incidence of pleural effusion, fever duration, hospitalization days, white blood cell count, neutrophil ratio, D-dimer level and use of other types of antibiotics were higher in the NP group than in the control group (P < 0.05). The control group exhibited a greater use of low molecular weight heparin (LMWH) than the NP group (P < 0.05). According to the multivariate logistic regression analysis, a white blood cell count > 12.3 × 10 9 /L (Odds ratio, OR = 6.412), a neutrophil ratio > 73.9% (OR = 6.081) and D-dimer level > 1367.5 ng/mL (OR = 8.501) were risk factors for pulmonary necrosis caused by MP. Furthermore, the use of LMWH (OR = 0.074) reduced the risk of pulmonary necrosis., Conclusions: NP is a rare complication of severe Mycoplasma pneumoniae pneumonia (SMPP), and although the clinical course is longer than common MP infection, the necrotic area is absorbed gradually. In patients with SMPP presenting with lobar consolidation, a white blood cell count > 12.3 × 10 9 /L, a neutrophil ratio > 73.9% and D-dimer level > 1367.5 ng/mL are risk factors for pulmonary necrosis, and the use of LMWH reduces the risk of pulmonary necrosis.

Background: Children are especially vulnerable to pneumonia and the effects of air pollution. However, little is known about the impacts of air pollutants on pediatric admissions for Mycoplasma pneumonia. This study was conducted to investigate the impacts of air pollutants on pediatric hospital admissions for Mycoplasma pneumonia in Shanghai, China., Methods: A cross-sectional design was applied to explore the association between pediatric hospital admissions and levels of air pollutants (fine particulate matter, particulate matter, ozone, sulfur dioxide, nitrogen dioxide, and carbon monoxide). Data on hospital admissions for pneumonia and levels of ambient air pollutants were obtained for the period of 2015 to 2018. Associations between pediatric admissions for Mycoplasma pneumonia and ambient air pollutants were calculated using logistic regression and described by the odds ratio and relevant 95% confidence interval. The hysteresis effects of air pollutants from the day of hospital admission to the previous 7 days were evaluated in single-pollutant models and multi-pollutant models with adjustments for weather variables and seasonality. Lag 0 was defined as the day of hospital admission, lag 1 was defined as the day before hospital admission, and so forth., Results: In the single-pollutant models (without adjustment for other pollutants), pediatric hospital admissions for pneumonia were positively associated with elevated concentrations of nitrogen dioxide and fine particulate matter. A 0.5% increase in daily admissions per 10-μg/m 3 increase in the nitrogen dioxide level occurred at lag 1 and lag 2, and a 0.3% increase in daily admissions per 10-μg/m 3 increase in fine particulate matter occurred at lag 1. In the multi-pollutant models, nitrogen dioxide and fine particulate matter remained significant after inclusion of particulate matter, ozone, sulfur dioxide, and carbon monoxide., Conclusions: This study illustrated that higher levels of nitrogen dioxide and fine particulate matter increase the risk of pediatric hospitalization for Mycoplasma pneumonia in Shanghai, China. These findings imply that the high incidence of Mycoplasma pneumonia in children in Asia might be attributed to the high concentration of specific air pollutants in Asia.

Background: Community-acquired pneumonia (CAP) is one of the leading worldwide causes of childhood morbidity and mortality. Its disease burden varies by age and etiology and is time dependent. We aimed to investigate the annual and seasonal patterns in etiologies of pediatric CAP requiring hospitalization., Methods: We conducted a retrospective study in 30,994 children (aged 0-18 years) with CAP between 2010 and 2015 at 23 nationwide hospitals in South Korea. Mycoplasma pneumoniae (MP) pneumonia was clinically classified as macrolide-sensitive MP, macrolide-less effective MP (MLEP), and macrolide-refractory MP (MRMP) based on fever duration after initiation of macrolide treatment, regardless of the results of in vitro macrolide sensitivity tests., Results: MP and respiratory syncytial virus (RSV) were the two most commonly identified pathogens of CAP. With the two epidemics of MP pneumonia (2011 and 2015), the rates of clinical MLEP and MRMP pneumonia showed increasing trends of 36.4% of the total MP pneumonia. In children < 2 years of age, RSV (34.0%) was the most common cause of CAP, followed by MP (9.4%); however, MP was the most common cause of CAP in children aged 2-18 years of age (45.3%). Systemic corticosteroid was most commonly administered for MP pneumonia. The rate of hospitalization in intensive care units was the highest for RSV pneumonia, and ventilator care was most commonly needed in cases of adenovirus pneumonia., Conclusions: The present study provides fundamental data to establish public health policies to decrease the disease burden due to CAP and improve pediatric health.

Objectives: The impact of atopy on disease severity and extrapulmonary manifestations in children with Mycoplasma pneumoniae (MP) pneumonia is unknown., Methods: Patients diagnosed with MP pneumonia between January 2016, and December 2017, were enrolled in this study. A total of 150 MP pneumonia patients were enrolled at diagnosis and divided into the atopic group (n = 48) and the nonatopic group (n = 102). Furthermore, these patients were also assessed after being divided into the pulmonary group (n = 120) and the extrapulmonary group (n = 30). Clinical characteristics, respiratory disease severity, any allergy history, and specific allergen sensitizations were collected from all patients. The serum interleukin-17 (IL-17) and total immunoglobulin E (lgE) levels were also measured., Results: More children in the atopic group than those in the nonatopic group presented with severe MP pneumonia, tachypnea, oxygen therapy, steroid treatment, atopic conditions including asthma attack, a previous history of asthma, decreased IL-17 levels, and increased IgE levels (all P < 0.05). When compared with those in the pulmonary group, the patients in the extrapulmonary group showed higher percentages of atopy, higher total lgE levels, and lower IL-17 levels (all P < 0.05)., Conclusions: Atopy may be a risk factor for disease severity and extrapulmonary manifestations in children with MP pneumonia., (© 2019 The Authors. Journal of Clinical Laboratory Analysis Published by Wiley Periodicals, Inc.)

Background: Mycoplasma pneumoniae (M. pneumoniae) is one of the most common causes of community-acquired pneumonia in children. Recent studies demonstrated that the incidence of severe or fatal M. pneumoniae was gradually increasing, which may be related to the excessive inflammation. However, the exact pathogenesis of excessive inflammation in Mycoplasma pneumoniae pneumonia(MPP) is still unclear. This study aimed to reveal the role of miR-29c/B7-H3/Th17 axis in children with MPP., Methods: Children hospitalized in Respiratory Department during Jan. 2014 to Dec. 2015 were enrolled. All children enrolled was confirmed with MP infection using real-time PCR and ELISA. Children were excluded if they were co-infected with other pathogens. A total of 52 children with MPP and 26 controls were enrolled. miR-29c expression in monocytes of children with MPP was determined by real-time PCR and soluble B7-H3 (sB7-H3) and IL-17 were determined by ELISA, and explore their clinical significance. miR-29c overexpression and silencing technology and luciferase reporter assay were performed to confirm whether B7-H3 is the direct target of miR-29c. The levels of transcription factor ROR-γt in CD4+ T cells and cytokine IL-17A in supernatant were detected after stimulated by different concentrations of B7-H3 fusion protein in vitro., Results: Of all 52 children with MPP, the mean age of the children were 77 ± 33 months, and 23 cases were male accounting for 44.2%. Nineteen cases had pleural effusion accounting for 36.5%. Children with MPP had significantly lower level of miR-29c and higher level of sB7-H3 and IL-17 compared to controls (both P < 0.05). The level of miR-29c significantly increased during convalescent phase compared to that of acute phase while sB7-H3 and IL-17 significantly decreased during convalescent phase (both P < 0.05). There was a positive correlation between the level of sB7-H3 and IL-17 in children with MPP during acute-stage (r = 0.361,P = 0.009). Children with MPP combined with pleural effusion had significantly higher level of sB7-H3 compared to those without pleural effusion (9952.3 ± 3065.3 vs. 7449.7 ± 2231.5, pg/ml), and the levels of sB7-H3 was positively correlated with the number of days of fever. The level of miR-29c was negatively correlated with M. pneumoniae specific IgG, IgM level. High concentrations of B7-H3(15μg/ml) could enhance ROR-γt expression and increase IL-17A. Functional studies based on luciferase reporter assay and immunofluorescence staining suggested that B7-H3 is the direct target of miR-29c, and miR-29c silencing or overexpression could up- or down-regulate the expression of B7-H3 in THP-1 cells., Conclusions: The axis of miR-29c/B7-H3/Th17 plays a vital role in children with MPP through excessive inflammation. miR-29c and B7-H3 may be the new target for the prevention and treatment of MPP, and may be the novel and potential biomarkers for the assessment of prognosis.

Objective: To clarify therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin against macrolide-resistant Mycoplasma pneumoniae (MRMP) pneumonia and against macrolide-sensitive Mycoplasma pneumoniae (MSMP) pneumonia in pediatric patients., Methods: A prospective, multicenter observational study was conducted from July 2013 to August 2015. The therapeutic effects of azithromycin, clarithromycin, minocycline and tosufloxacin were evaluated in 59 patients with pneumonia caused by MRMP and in 50 patients with pneumonia caused by MSMP. In vitro activities of antimicrobial agents against isolates of Mycoplasma pneumoniae were also measured., Results: Mean durations of fever following commencement of treatment in patients infected with MRMP and MSMP were 5.2 and 1.9 days, respectively (log-rank test, P < 0.0001). Among patients infected with MRMP, mean durations of fever were 4.6, 5.5, 1.0 and 7.5 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P < 0.0001). Among patients infected with MSMP, mean durations of fever were 2.5, 1.7, 0.9 and 4.3 days for patients treated with azithromycin, clarithromycin, minocycline and tosufloxacin, respectively (log-rank test, P = 0.0162). The MIC90s of azithromycin and clarithromycin among the 27 isolates of MRMP were 64 and 256 μg/ml, respectively, and those among the 23 isolates of MSMP were <0.000125 and 0.001 μg/ml, respectively. The MIC90s of minocycline and tosufloxacin among the 27 isolates of MRMP were 1.0 and 0.25 μg/ml, respectively, and those among the 23 isolates of MSMP were 1.0 and 0.5 μg/ml, respectively., Conclusion: Both minocycline and tosufloxacin showed good in vitro activities against MRMP. Minocycline, but not tosufloxacin, shortened the duration of fever in pediatric patients infected with MRMP compared to the duration of fever in patients treated with macrolides.

Through detection and analysis of the changes of interleukin (IL)-2 and IL-10 in children with mycoplasma pneumoniae pneumonia (MPP), this study aimed to explore the role of cytokines in the pathogenesis of pediatric MPP as well as immunological pathogenesis of MPP, to provide guidance for clinical diagnosis, assessment and treatment of MPP. Enzyme linked immunosorbent adsorption (ELISA) analysis was applied to determine the expression level of IL-2 and IL-10 in serum. According to the experimental results, we found that the expression levels of IL-2 and IL-10 changed significantly in different phases of MPP in comparison with a healthy control group and a case control group. The expression levels of IL-2 and IL-10 can be used as an important indicator for early diagnosis of MPP. Accordingly, detection of IL-2 and IL-10 is of great significance to the diagnosis of MPP and studies on their roles can provide guidance for treatment.

Objective: To study the changes in serum tumor necrosis factor-&alpha; (TNF- &alpha;), interleukin-6 (IL-6) and galctin-3 (Gal-3) concentrations in children with Mycoplasma pneumoniae pneumonia (MPP), and their roles in MPP., Methods: Serum TNF-&alpha;, IL-6 and Gal-3 concentrations were measured using double antibody sandwich ELISA in 48 children with acute MPP (severe: 21 cases; mild: 27 cases) and in 30 healthy children (control group)., Results: Serum concentrations of TNF-&alpha;, IL-6 and Gal-3 in both the severe and mild groups were significantly higher than in the control group before treatment. The concentrations of the three indexes in the severe group were significantly higher than in the mild group. Serum concentrations of the three indexes decreased significantly after treatment in both groups., Conclusions: Serum TNF-&alpha;, IL-6 and Gal-3 play important roles in the occurrence and development of pediatric MPP and their levels are associated the severity of this disorder.

Objective: To study the clinical characteristics of pediatric Kawasaki disease complicating mycoplasma pneumoniae pneumonia., Methods: Retrospective analysis was conducted on 11 children who had been diagnosed with Kawasaki disease with Mycoplasma pneumoniae pneumonia., Results: The 11 cases presented with varying degrees of fever, conjunctival congestion, skin rashes, lymphadenectasis, distal extremities lesions, heart and lung lesions. 8 of them were standartly treated with azithromycin, while 3 of them were treatad with azithromycin and erythromycin. 2 patients with pleural effusion complicated by lobar pneumonia consolidation were treated with gamma globulin combined aspirin. All of the 11 patients were healed., Conclusion: Infections are common at the diagonosis of KD. Reasonable examination and antibiotics is useful to cure KD with MPP.

Objective: Community-acquired pneumonia (CAP) remains a major cause of death. No studies have reported the use of rapid influenza diagnostic tests (RIDT) for the etiological diagnosis, and the factors contributing to severity and mortality have not yet been fully investigated. The aim of this study was to review the etiologies of CAP using RIDT and to identify risk factors related to the severity and mortality of the disease., Methods: This retrospective study assessed these factors in hospitalized patients, with special emphasis on microbial etiology., Results: A total of 1,032 patients aged 63.9±18.3 years were studied, 66.2% of whom were men. Microbial identification was obtained in 57.0% of the cases. The most frequent causative microbial agents were Streptococcus pneumoniae, Mycoplasma pneumoniae and the influenza virus, and the second most frequent pathogens in the patients with severe CAP and the non-survivors were S. pneumoniae and the influenza virus. Age (≥65 years), chronic obstructive pulmonary disease, congestive heart failure, diabetes mellitus, dementia and Legionella spp. infection and polymicrobial infection were each found to be independent factors related to severity in the multivariate analysis, whereas "unidentified pathogen" was found to be an independent factor for non-severe CAP. Age (≥65 years), chronic pulmonary aspergillosis, post-lung cancer surgery and severe CAP were found to be independent factors for non-survival according to a multivariate analysis., Conclusion: In addition to S. pneumoniae, the influenza virus was a frequent cause of CAP overall and a frequent causative pathogen in both severe cases of CAP and non-survivors. Legionella spp. infection and polymicrobial infection were found to be an independent factor for the severity of CAP along with advanced age and certain comorbidities. An advanced age, certain respiratory comorbidities and severe CAP were found to be important independent factors for the mortality of CAP.

Eighteen out of 45 children were reported to have a respiratory illness during an outbreak at a temporary dormitory in a nursery school in China in 2011. To study the outbreak and to determine the risk factors for infection, an epidemiological investigation was performed. A standardized questionnaire was completed for a total of 45 children with the help of their guardians and parents. In addition, acute- and convalescent-phase serum samples and throat swabs from the children were taken for laboratory diagnosis. The diagnosis of a Mycoplasma-like illness was based on the following clinical criteria. The criteria were onset of illness after 31 May 2011, characterized by a cough, fever(>37.5 °C), or at least 3 of the following symptoms: fever, sore throat, cough or expectoration, and runny or stuffy nose. PCR-restriction fragment length polymorphism (PCR-RFLP), determination of MICs, and sequencing were performed to determine the genotype, antibiotic resistance, and sequence polymorphisms of the isolated strains, respectively. The paired sera revealed that 15 patients were infected with Mycoplasma pneumoniae. Epidemiology confirmed that this was a point source outbreak, characterized by a short incubation period, a high secondary attack rate, and a long period of hospitalization. PCR-RFLP analysis revealed that the 12 isolated strains of M. pneumoniae shared the same subtype P1 gene, and 23S rRNA sequence analysis showed that these strains harbored two macrolide-resistant gene-related point mutations at position 2063 and 2617. In this outbreak, the major risk factor was the distance between the bed of the first patient and the beds of close contacts (beds less than three meters apart). The strains isolated in this study were found to harbor two point mutations conferring macrolide resistance, indicating the importance of pathogen and drug resistance surveillance systems.

Objective: To study the levels and roles of cytokines TNF-α, IL-6 and IL-10 in bronchoalveolar lavage fluid (BALF) in children with Mycoplasma pneumoniae pneumonia (MPP)., Methods: The levels of TNF-α, IL-6 and IL-10 in BALF were measured using ELISA in children with MPP at acute stage (n=45) and at remission stage (n=30). Twenty children without lung lesions severed as the control group., Results: The TNF-α, IL-6 and IL-10 levels in BALF were higher in children with MPP at acute stage than those in the control group (P<0.05). The levels of TNF-α and IL-6 in BALF at remission stage were reduced to the levels similar to the control group and were significantly lower than those at the acute stage in children with MPP. However, the levels of IL-10 in BALF remained at higher levels at remission stage in children with MPP., Conclusions: The levels of TNF-α, IL-6 and IL-10 in BALF increase in children with MPP at acute stage, suggesting that the cytokines may be involved in the pathogenesis of MPP.

The subject of atypical pneumonias is of great medical and historical interest to modern physicians. Although these diseases have no doubt affected humans throughout our history, it is not until the mid-twentieth century that physicians first began to differentiate certain atypical pulmonary infectious processes from typical pneumonia. Physicians at the time were unclear as to the precise etiology of these infections. As time progressed and study of these organisms continued, physicians were better able to identify the causative agent and devise tests with which to detect the disease. This article focuses on the description and ultimate identification of Mycoplasma pneumoniae., (Copyright 2010 Elsevier Inc. All rights reserved.)

Prospective studies have suggested that some individuals have a persistent IgM response to Mycoplasma pneumoniae infection with relatively little IgG production over many months. Persistence of the organism in patients with an allergic phenotype might predispose to the development of asthma. This study was designed to analyze the prevalence of M. pneumoniae infection and the immune response to that infection among children with asthma compared with controls. A prospective study was performed in 82 children with physician-diagnosed asthma and 98 nonasthmatic controls over a 5-year period comparing them for evidence of current or prior infection by M. pneumoniae using serology (IgG and IgM), culture, and polymerase chain reaction (PCR), and in vitro cellular responses to M. pneumoniae antigen. Similar numbers of controls (9/98) and asthmatic children (6/82) were PCR(+) for M. pneumoniae at some time during the study. IgM antibody to M. pneumoniae was detected in similar numbers of controls (21/98) and asthmatic children (18/82), but positive IgG antibody titers were detected in significantly more controls (13/98) than asthmatic children (3/82; p = 0.03). Similar numbers from each group were IgM(+) on more than one annual visit (9/98 controls and 7/82 asthmatic children). Antigen-driven proliferation and interferon (IFN) gamma production by mononuclear cells from IgM(+) controls were significantly greater than that of IgM(-) controls, but there was no difference in proliferation and IFN-gamma production by cells from IgM(+) and IgM(-) asthmatic children. These results suggest that asthmatic children have deficient cellular and humoral responses to M. pneumoniae infection compared with nonasthmatic controls.

A 55-year-old woman who developed severe hypoxemia associated with severe pneumonia was admitted to our hospital for mechanical ventilation. She was treated with antibiotics under a diagnosis of mycoplasma pneumonia. Although most clinical findings improved, hypoxemia remained. As a chest CT film showed multiple nodules and an enhanced CT film revealed arterial filling in the nodules, multiple pulmonary arteriovenous fistulas (PAVFs) were considered to be an underlying cause of hypoxemia. Transcatheter coil embolization for 5 PAVFs, significantly ameliorated hypoxemia in the patient. PAVF is a congenital desease, and in many cases, is asymptomatic. Therefore, it was rare for PAVFs to be detected in a middle-aged patient with prolonged hypoxemia associated with pneumonia.

Mycoplasma pneumoniae is the only mycoplasma clearly involved in respiratory tract infections in man. Implicated most often in tracheobronchitis, it is the second most frequent agent responsible for community-wide bacterial pneumonia, and in addition it probably causes asthma exacerbations. M. pneumoniae infection occurs endemically, with epidemic peaks every four to seven years, mostly in children above five years of age. The laboratory diagnosis of these infections, mainly by serology, is made only in severe cases because of the fastidious growth of this microorganism. M. pneumoniae can, however, be detected easily by molecular amplification techniques. Macrolides and related antibiotics are considered the treatment of choice for M. pneumoniae infection in both adults and children. Antibiotic sensitivity testing of M. pneumoniae is not done routinely because resistant isolates have only rarely been described, the results are delayed, and they have no immediate therapeutic consequence.

Background: To study the role played by eosinophil cationic protein (ECP) in patients with Mycoplasma pneumonia infection., Methods: Pediatric patients aged 4 to 14 years old were divided into 3 groups, each consisting of 30 patients. Group 1 comprised patients with known M. pneumoniae infection. Group 2 comprised patients with asthma who were in a stable condition with no infection, acute asthma exacerbation or steroid use in the last 2 months. Group 3 consisted of healthy children and was designated the control group. The level of ECP in patients' serum was measured by an ECP radioimmunoassay kit., Results: There were 90 children enrolled in this study; 59 (65.56%) were boys and 31 (34.44%) were girls. Mean serum ECP levels between males and females was not significantly different (p = 0.544). The variance of serum ECP levels decreased as patient age increased, but there was no relationship between serum ECP level and patient age (gamma = 0.118, p = 0.267). Serum ECP levels were similar in both the M. pneumoniae-infected and asthma groups; serum ECP levels in the control group were less than the levels seen in the other 2 groups. The difference in serum ECP levels among the 3 groups was statistically significant (p < 0.001)., Conclusion: Both the children who had M. pneumoniae infection and the children with asthma had significantly increased serum ECP levels compared to normal healthy children. The elevated ECP levels found in the serum of patients with M. pneumoniae infection may be associated with damage to the respiratory epithelium and accelerated hypersensitivity in the respiratory system. Decreasing the serum level of ECP may potentially be a method of relieving symptoms in patients with M. pneumoniae infection. Additional studies are warranted to further validate this conclusion.

One of the challenges in planning the treatment of respiratory tract infection in children is identifying the causative agent. The objective of the present study was to investigate the incidence of Mycoplasma and Chlamydia in the etiology of respiratory tract infections of children. The present study included 100 children, three months to 12 years of age, admitted to the outpatient department of pediatrics with such respiratory symptoms as fever, cough and respiratory distress. Following a detailed clinical history and physical examination, complete blood count, erythrocyte sedimentation rate, peripheral blood smear and chest X-ray were obtained from each patient. At admission, IgG and IgM for Mycoplasma pneumoniae, Chlamydia pneumoniae, Chlamydia trachomatis and Chlamydia psittaci were determined serologically. Positive antibody titer was found for Chlamydia and Mycoplasma in 18 (18%) of the patients. It was found that 2% of the patients had acute C. pneumoniae infection. When the subjects who had infections in the past or had re-infection were also considered; 6% were infected with C. pneumoniae, 3% with C. trachomatis, 1% with C. psittaci and 8% with M. pneumoniae. The presence of eosinophilia (> or = 4%) or the presence of siblings in the house were considered as factors favoring Chlamydial infections. High antibody titers for M. pneumoniae and C. pneumoniae were found more frequently after the age of two. Patients older than two years should be evaluated carefully for antibiotic treatments against atypical agents in pediatric lower respiratory tract infections.

Objective: To study the clinical features and immune-mediated pathogenesis of mycoplasma pneumonia (MP) in children., Methods: The DNA of mycoplasma in nasopharyngeal swabs was detected by PCR in 485 children with respiratory tract infection, and serum circulating immune complex (CIC), IgG, IgM, MP IgM, and CH50 were measured on the same day in 45 children with pneumonia., Results: Significant difference was noted between the results of mycoplasma DNA PCR detection and those of serum IgM detection. The positivity rate of CIC was 44% in children with MP whereas that in the control group was only 10% (P<0.01). The levels of serum IgG and IgM in MP group was significantly higher and serum CH50 lower than those of the control group (P<0.05)., Conclusion: Mycoplasma DNA detection facilitates early diagnosis and treatment of MP, whose pathogenesis in children may be involved in immune-mediated mechanism.

As antimicrobial therapy for pneumonia has not been well established in Japan, this study was designed to obtain a more definitive standard for antimicrobial treatment of this condition. Two hundred and thirty-one emergency patients admitted to Kyorin University Hospital between January 1998 and December 2000 were retrospectively analyzed in respect to their age, underlying disease, causative organism, and primary treatment with antimicrobial agent. Furthermore, the severity and prognosis were analyzed for those patients who had not responded to initial treatment with antimicrobial agents. The majority of the patients were elderly (over 65 years old; mean overall age 66.7 +/- 15.2 years) and had severe pneumonia; underlying diseases were recognized at a high rate in patients with severe pneumonia (P < 0.05) and in those classified as elderly (P < 0.0001). The most common underlying conditions in elderly patients were respiratory, cardiovascular (P < 0.01), and cerebrovascular (P < 0.05) diseases. The most common causative organisms were Haemophilus influenzae, Staphylococcus aureus, Streptococcus pneumoniae, and Mycoplasma pneumoniae. In patients with severe pneumonia, S. aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa were identified as the most common causative organisms. Complications associated with antimicrobial treatment were observed in those patients with K. pneumoniae isolates who also had severe pneumonia and were frequently treated with penicillin. Furthermore, increased mortality rates were observed in patients not responding well to the initial treatment with antimicrobial agents. Thus, the selection of appropriate initial antimicrobial agents is an important factor affecting the prognosis of patients with community-acquired pneumonia.

Although Mycoplasma pneumoniae infections are common among school children and young adults, they have been rarely reported in renal transplant recipients. Herein, we report an 8-yr-old boy who had M. pneumoniae infection 1 yr after transplantation and showed liver dysfunction during the course of the disease. In children who underwent renal transplantation and receive immunosuppressive treatment, we suggest that symptoms of a simple upper respiratory tract infection may precede M. pneumoniae disease with potentially serious extrapulmonary complications., (Copyright 2004 Blackwell Munksgaard)

Coronavirus infection (CVI) was studied in 227 patients hospitalized in the clinic of the Research Institute of Hematology and Transfusiology in 1993-2003 with diagnosed acute and chronic leucosis, multiple myelogenic disease and aplastic anemia. Their blood sera and secretions of the nasal cavity were examined in the indirect hemagglutination (IHA) test with dried standard erythrocyte diagnostic preparations. CVI was shown to be activated in three year cycles in immunodeficient patients, which occurred, respectively, in 66.1, 56.9, 47.8 and 51.6% of cases in the above mentioned groups of patients. In 87% of cases CVI was associated with other respiratory pathogens, the following being prevailed: respiratory syncytial virus (37.9%), parainfluenza virus (32.2%) and Mycoplasma pneumoniae (36.8%). CVI was provoked by such factors as the course of the main disease and specific treatment, previous respiratory infections of other etiology with M. pneumoniae infection playing the leading role (60%). The most severe course of CVI was observed in patients with acute leucosis (in 75% of cases accompanied by lesions of lower respiratory tracts). The use of the highly sensitive IHA test made it possible to determine the potential for both serum and local antibodies production in the patients under observation.

Mycoplasma pneumoniae (M. pneumoniae) is one of the smallest free-living bacteria known. Along with other unique characteristics of this genus, it lacks the typical peptidoglycan cell wall of most eubacteria. Best known for causing tracheobronchitis and atypical pneumonia in humans, this pathogen also causes a number of extrapulmonary syndromes such as meningitis/encephalitis and arthritis. Recent studies also suggest that infection may be associated with chronic conditions such as asthma. Although the mechanisms of M. pneumoniae pathogenesis remain to be elucidated, one important component of M. pneumoniae infections is the induction of proinflammatory and other cytokines in both acute and chronic conditions. In this review, we survey the induction of cytokines by M. pneumoniae in different model systems, and we discuss the possible role of induced cytokines in M. pneumoniae pathogenesis.

We used a new polymerase chain reaction (PCR) system to identify the 16S rRNA gene of Mycoplasma pneumoniae and to diagnose lower respiratory tract infections caused by the microorganism. Nasopharyngeal swabs collected from 21 patients (22 episodes) tested positive for M. pneumoniae with the PCR. The age distribution of the patients was between 2 and 13 years. The diagnosis, including concomitant infection, was as follows: pneumonia (n = 11), acute bronchitis (n = 10), bronchial asthma (n = 4), and acute otitis media (n = 1). Six patients had bacterial superinfections. Positive findings for M. pneumoniae were noted together with exacerbation of asthma symptoms, suggesting that M. pneumoniae infection may play the role of an inducer. The PCR system constructed by us will contribute to revealing the clinical features of M. pneumoniae infection, and as a result, an appropriate chemotherapeutic agent can be chosen. We propose the usefulness of this PCR system to detect the microorganism in younger children.

Rates of acute Chlamydia pneumoniae and Mycoplasma pneumoniae infections were determined in 115 adults hospitalized for community-acquired pneumonia (CAP), purulent exacerbations of COPD and acute exacerbations of bronchial asthma, by means of serology and molecular methods. Results were compared with those obtained in a matched control group. Common respiratory pathogens were isolated by cultures in 22.5% and 22.2% of CAP and exacerbated COPD patients, respectively. Cultures from exacerbated asthma patients were always negative. Serological and molecular evidence of current C. pneumoniae infection was obtained in 10.0%, 8.9% and 3.3% of CAP, COPD and asthma cases. The corresponding rates of acute M. pneumoniae infection were 17.5%, 6.7% and 3.3%, respectively. Finally, no difference was found between typical and atypical pathogen rates. These findings highlight the importance of taking into account C. pneumoniae and M. pneumoniae infections in guiding the choice of empirical antibacterial treatment for CAP and purulent exacerbations of COPD.

Setting: In countries with high HIV rates, diagnosis of lower respiratory disease etiology is both challenging and clinically important., Objective: To determine the etiology of lower respiratory tract disease among persons with suspected tuberculosis (TB) and abnormal chest X-rays in a setting with very high HIV seroprevalence., Design: Cross-sectional prevalence data from a prospective cohort of predominantly hospitalized adults with suspected TB in Botswana, January-December 1997., Results: Of 229 patients, 86% were HIV-positive and 71% had a pathogen identified. TB was confirmed in 52%, 17% had acute mycoplasma pneumonia, 3% had Pneumocystis carinii, 27% grew a bacterial pathogen from sputum and 8% from blood. Ninety-four per cent of TB diagnoses were made through expectorated sputum and only 5% of TB cases were diagnosed by sputum induction alone. Polymerase chain reaction (PCR) for Mycobacterium tuberculosis had positive and negative predictive values of 94% and 59%, respectively. Male sex, cough < 2 weeks, and tuberculin skin test > or = 5 mm were independently associated with culture-positive TB among persons with negative acid-fast bacilli smears. Co-infection with two or more pathogens occurred in 25%., Conclusions: Mycoplasma pneumoniae infection was quite common despite clinical suspicion of TB, and sputum induction and PCR did not significantly improve our ability to diagnose TB, although clinical presentation had some predictive value.

Community-acquired pneumonia (CAP) constitutes a major cause of morbidity and mortality. Although Streptococcus pneumoniae remains the bacterium most commonly implicated in CAP, the atypical respiratory pathogens Mycoplasma pneumoniae, Legionella species, and Chlamydia pneumoniae are being isolated with increasing frequency Contrary to previous beliefs, these agents are capable of causing severe as well as mild-to-moderate illness. Moreover, they can affect all age groups. Indeed, atypical pathogens are implicated in up to 40% of CAP cases and commonly occur as copathogens in mixed-infection CAP, an etiology associated with particularly high mortality (up to 25%). Laboratory methods for detecting atypical pathogens are slow, and there is significant overlap between atypical and typical CAP manifestations. For these reasons, accurate prediction of etiology cannot be made purely on clinical or radiologic grounds. Consequently, empiric antimicrobial therapy for atypical pathogens (with agents such as macrolides, fluoroquinolones, in some cases tetracyclines, or the new ketolides) warrants careful consideration and now is recommended for the treatment of CAP.

Gender is a significant factor in determining the susceptibility to and severity of pulmonary diseases in both humans and animals. Murine respiratory mycoplasmosis (MRM), due to Mycoplasma pulmonis infection, is an excellent animal model for evaluation of the role of various host factors on the development of acute or chronic inflammatory lung diseases. MRM has many similarities to mycoplasma respiratory disease in humans. The purpose of the present study was to determine whether gender has a significant impact on lung disease due to M. pulmonis infection in mice. It was demonstrated that male mice consistently developed more severe disease in the lung parenchyma than did female mice. There was no gender difference in disease severity along the airways or any difference in mycoplasma numbers in lungs of male and female mice. Furthermore, surgical removal of reproductive organs reduced the severity of mycoplasma disease and the numbers of mycoplasma organisms recovered from lungs. Thus, gender plays a significant role in determining the severity of M. pulmonis disease. In fact, the gender of the host was a major factor in determining whether an acute or chronic inflammatory lung disease developed after infection with M. pulmonis.

175 children with acute bronchopulmonary pathology were examined for the presence of the pneumotropic infective agents by serological and bacteriological methods. In most children microbial associations with the prevalence of mycoplasmas, pneumocycts and, to a lesser extent, chlamydiae were detected. The considerable activation of cytomegalovirus (CMV) infection in children with pneumonia and bronchitis was noted. Taking into account the results of the examination and the clinico-anamnestic data, the character of infections could be established: chlamydial and CMV infections were mainly persisting; pneumococcal infection was mainly acute, hemophilic and pneumocyst infections were mixed. The clinical picture of acute pneumonia cases had characteristic features determined by the supposed etiological agent, but this picture could change under the influence of pneumotropic infective agents.

At a secondary school in Budapest, in the first class, 30 students became sick with fever and upper respiratory catarrhal symptoms between September 19 and October 31, 1995. Two children were hospitalized with a diagnosis of pneumonia, in case of the two children treated at the Szent László Hospital, suspect of Mycoplasma infection raised which was also confirmed by cold agglutination test. During the epizootiological examination on the spot they found a terrarium in the classroom where the students raised a Syrian gold hamster family. Mycoplasmas were isolated from the lung samples of the hamsters during the pathological examination which proved to be Mycoplasma pneumoniae. Owing to the close etiologic relationships between epidemiological anamnesis, characteristics of the epidemic, as well as findings of patients and pathological or histological findings in the hamsters together with the results of bacteriological examinations, the epidemic should be considered as a zoonosis.

Mycoplasma hominis is a commensal of humans. The organism has been predominantly associated with infections of the genitourinary tract. Extragenital infections have been described in neonates, in women during the postpartum period, and in immunocompromised patients. Pneumonia caused by M. hominis is very rare. This report describes the development of M. hominis pneumonia in a lung transplantation recipient and underscores the difficulty in establishing the correct diagnosis and the need for early and aggressive treatment with appropriate antimicrobial agents to insure a good outcome.

Animal model studies of Mycoplasma pneumoniae infection after live respiratory challenge were conducted to investigate the issues of challenge-rechallenge associated accentuated pathology, postparenteral vaccination associated accentuated pathology, and oral vaccination. Live M. pneumoniae inocula were grown in hamster serum-based medium in order to reduce the potential for the serum growth component to participate in the hyperaccentuated histopathological response as seen with challenge-rechallenge experiments which have used horse serum-based growth media. Despite the use of homologous animal serum, an early hyperaccentuated response occurred (day 3 score 13.3 vs day 10 score 7.7; P = 0.02) which included perivascular infiltrates, and histopathological scores for early (day 3) and late (day 10) disease were similar (P > 0.10) between experiments of challenge-rechallenge when either homologous or heterologous sera were used in inoculum growth media. Parenteral vaccination with heat-killed bacteria also led to an early hyperaccentuated histopathological response after live respiratory challenge (scores on day 3: vaccinated 18.3, unvaccinated 6.2; P < 0.01) and this response was not significantly diminished when inocula were cleaned of growth medium components. An early accentuated response did not follow oral vaccination with heat-killed bacteria (score on day 3: vaccinated 5.7) and the late reaction was significantly less after challenge (scores on day 10: vaccinated 10.3, unvaccinated 14.6; P = 0.011). Studies of parenteral vaccination should include analyses for early disease after live challenge. Oral vaccination offers a promising route for stimulating protective immunity while minimizing undesirable recall immune events.

Background: Mycoplasma pneumoniae pneumonia is regarded as a community-acquired pneumonia, rarely requiring hospitalization, with sporadic cases or limited outbreaks occurring after close contacts with an infected patient. Few reports mention M pneumoniae pneumonia acquired during hospitalization., Patients and Methods: M pneumoniae was diagnosed in patients who developed pneumonia following perioperative and postoperative assisted ventilation by the isolation of M pneumoniae from bronchial washing, the detection of M pneumoniae DNA from bronchial washing, and serologic testing for the presence of specific immunoglobulin M (IgM) antibodies., Results: Four patients were diagnosed as having M pneumoniae pneumonia following mechanical ventilation over a 1 1/2-year period. They were men, older than 50 years, and were hospitalized for vascular surgery. They developed febrile hypoxemia and intersticial pneumonia. Isolation of M pneumoniae and detection of M pneumoniae DNA were positive in 1 case; specific IgM antibodies were present in 4 cases., Conclusions: These observations allow the description of a new clinical entity and highlight the role of M pneumoniae as an agent of nosocomial infections. This diagnosis should be considered in any patient with precocious post-assisted ventilation febrile hypoxemia and diffuse interstitial pneumonia, and empiric treatment protocols may include M pneumoniae in their spectrum.

The data on the incidence of Chlamydia and Mycoplasma infections in children with inflammatory diseases of the respiration organs are presented. The peculiarities of the clinical manifestations and the attempts to carry out the clinical differential diagnostication are described. The chemotherapeutic efficacies of erythromycin, rifampicin and tetracycline in the treatment of pneumonia due to Chlamydia and Mycoplasma in children were studied. There was observed similarity in the clinical signs of the infections. The differential diagnostication without the data on the disease etiology was shown impossible. Marked chemotherapeutic efficacies of erythromycin and rifampicin in the treatment of chlamydiosis and mycoplasmosis in infants were stated. The tetracyclines were found to be efficient in the treatment of older children.

The authors show a literary review on Mycoplasma pneumonia which represents a fifth of human pneumonia. M. pneumoniae is the major cause of illness in school-age children (5-9 years) and young adults and the peak incidence of illness occurs in this age. The infection appears mainly as an interstitial pneumonitis and the onset of illness is gradual, influence-like with few clinical symptoms and typical roentgenographic and bronchoscopic findings. Cold hemagglutinins appear in approximately 50% of patients. A severe prognosis can be associated with extrarespiratory symptoms; Erythromycin (as others macrolides) is the drug of choice.

Carbohydrate-mediated interactions are prominent in the pathobiology of human infection with Mycoplasma pneumoniae. The mycoplasma uses specific long-chain sialo-oligosaccharides at the host-cell surface as receptors. These sialo-oligosaccharides contain I antigen in their backbones, and they are richly expressed at the primary site of infection--the ciliated bronchial epithelium--and on erythrocytes. The autoantibodies of high titers directed to I antigen, cold hemagglutinins, frequently produced in this infection are therefore antibodies to receptors and may be triggered by an autoimmunogenic mycoplasma-receptor complex in which the lipid-rich microorganism serves as an adjuvant. Current interest is focused on the possibility that the course of infection with human immunodeficiency virus type 1 (HIV-1) may be exacerbated by coinfection with mycoplasmas. One mechanism for such potentiation would be specific interactions between the mycoplasmas and HIV-1 leading to a concentration of the virus at the mycoplasmal surface. The envelope glycoprotein gp120 of HIV-1 is richly decorated with an array of oligosaccharides whose biosynthesis is host cell directed. By an analogy with M. pneumoniae, I propose that recognition of carbohydrates by various mycoplasmal copathogens is a potential mechanism for interactions with HIV-1.

Patients with congenital or acquired disorders of antibody production suffer from a wide variety of infections. They are most often bacterial and due to Haemophilus influenzae or Streptococcus pneumoniae. Chronic pulmonary disease accounts for most of the deaths. While non-urogenital tract infections due to Ureaplasma urealyticum or other mycoplasmas are unusual in individuals with normal resistance, patients with antibody deficiency demonstrate a unique susceptibility. With increasing frequency, patients with impaired humoral immunity have been shown to have a mycoplasmal infection that results in pneumonitis, sinusitis, cystitis, arthritis, osteomyelitis, or cellulitis. The mycoplasmas may be responsible for chronic sinopulmonary disease in a majority of such patients. Awareness of the role these organisms play in causing infection in antibody-deficient patients and the institution of appropriate antibiotic therapy will contribute to an improvement in clinical outcome.

Three young children with Down syndrome developed fever, cough, wheezing, irritability, and tachypnea. They had bilateral infiltrates on their chest radiographs and developed respiratory distress, which required their hospitalization. Laboratory studies suggested that the children had mycoplasma pneumonia. These children may have experienced severe mycoplasma infections early in life because of their Down syndrome-associated immune abnormalities. When young children with Down syndrome develop pneumonia, physicians should consider Mycoplasma pneumoniae as the possible etiologic agent.

Guinea-pigs were infected intranasally with Mycoplasma genitalium or Mycoplasma pneumoniae. The lung lesions produced by the two mycoplasmas were comparable in extent and histological pattern. Sera of both animal groups taken 2 weeks after infection reacted strongly in the complement fixation test with the M. pneumoniae glycolipid extract. In an ELISA using the respective adherence proteins (P1-protein of M. pneumoniae and MgPa of M. genitalium), strong specific activity, but also considerable cross-reactions were found. Epitope analysis by using overlapping octapeptides of a P1-region immunologically active in human M. pneumoniae infections and of the corresponding MgPa-region revealed six common epitopes but also one M. genitalium and two M. pneumoniae specific determinants. For analysis of a possible pathogenicity of M. genitalium in the human respiratory tract species-specific tests have to be developed.

The paper analyzes the data on the prevalence of human Mycoplasma infections in the USSR and on their diagnostic methods. It also provides evidence for the pathogenicity and biological properties of M. incognitus, a new species, and defines the ways and prospects for further investigations in theoretical and practical Mycoplasma research.