Detection of Mycoplasma pneumoniae in children with lower respiratory tract infections

Mycoplasma pneumoniae is known to be a major cause of lower respiratory tract infections (LRTIs) in children. We studied 75 children who had been hospitalized for community-acquired LRTIs for the detection of M. pneumoniae by serological analysis and polymerase chain reaction (PCR) to amplify a 277-base pair region of 16S rDNA gene of M. pneumoniae applied to throat swab specimens. Serological and/or PCR positive results diagnosed M. pneumoniae infection in 23 (30.7%) patients.     

Long-term epidemiology of infections with Mycoplasma pneumoniae.

Pneumonia due to Mycoplasma pneumoniae was monitored in a large prepaid medical-care group in Seattle, Washington, between 1963 and 1975. The disease was diagnosed by isolation of M. pneumoniae and/or significant rises in titer of complement-fixing (antilipid) antibody in paired sera. Infection was endemic without significant seasonal fluctuations. Two epidemics occurred: the first peaked in January 1967, the second late in the summer of 1974. Total rates of pneumonia infection in children increased during M. pneumoniae epidemics, but epidemics of infection with respiratory syncytial virus had a greater effect. Age-specific attack rates for M. pneumoniae pneumonia among children aged five to nine years (about six per 1,000) were about twice the rates for younger children and four times those for adults. Serologic study of healthy schoolchildren showed annual rates of infection that paralleled but greatly exceeded rates of recognized M. pneumoniae pneumonia. Infection rates varied from 2% in endemic years to 35% in epidemic periods. A higher proportion of infections among children aged five to nine years than among adolescents aged 15-19 years resulted in pneumonia.     

Chlamydia and Mycoplasma serology in respiratory tract infections of children

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.     

Importance of acute Mycoplasma pneumoniae and Chlamydia pneumoniae infections in children with wheezing.

In order to evaluate the role of Mycoplasma pneumoniae and Chlamydia pneumoniae in reactive airway disease, 71 children aged 2-14 yrs with an acute episode of wheezing and 80 age-matched healthy children were studied. Sera for the determination of specific antibody levels and nasopharyngeal aspirates for the detection of M. pneumoniae and C. pneumoniae deoxyribonucleic acid were obtained on admission and after 4-6 weeks. All children with wheezing received a standard therapy with inhaled corticosteroids and bronchodilators for 5-7 days; when antibiotic was added on the basis of the judgement of the paediatrician in charge, clarithromycin 15 mg.kg body weight(-1).day(-1) for 10 days was used. Acute M. pneumoniae and C. pneumoniae infections were detected significantly more often in children with wheezing than in controls. In patients infected with one of the two pathogens, a history of recurrent wheezing was significantly more frequent than in those without either infection. During a 3-month follow-up period, among nonantibiotic-treated children, those with acute M. pneumoniae and/or C. pneumoniae infection showed a significantly higher recurrence of wheezing than those without acute M. pneumoniae and/or C. pneumoniae infection (p=0.03). These results highlight the apparently significant relationship of Mycoplasma pneumoniae and Chlamydia pneumoniae with wheezing in children, particularly in subjects with a history of recurrent episodes, and the possible improvement in the course of reactive airway disease within paediatric patients with acute Mycoplasma pneumoniae and/or Chlamydia pneumoniae infection.     

Mycoplasma pneumoniae and Chlamydia pneumoniae infections in children with pneumonia. Mowgli Study Group.

The most common clinical signs, host responses and radiographic patterns were studied in 203 Italian children hospitalized for community-acquired pneumonia in order to clarify the role of clinical and radiological characteristics in the diagnosis of Mycoplasma pneumoniae and/or Chlamydia pneumoniae infections. Antibody measurements in paired sera and polymerase chain reaction on nasopharyngeal aspirates were used to establish the diagnoses of acute M. pneumoniae and C. pneumoniae infection, and the aetiologic data were correlated with the clinical, laboratory and radiographic data obtained on admission. No significant association was observed between evidence of M. pneumoniae and/or C. pneumoniae infection and periods of episode during the year, mean age of the study subjects, individual symptoms, physical findings or laboratory test results. Furthermore, no significant correlation was observed in relation to the radiological findings and M. pneumoniae and/or C. pneumoniae infection. This study shows that neither clinical findings nor laboratory parameters distinguished Mycoplasma pneumoniae and/or Chlamydia pneumoniae infection in children with pneumonia. Radiological findings also have a limited capacity to differentiate aetiologic agents. The priorities for future research include the development of rapid, easily accessible and cost-effective diagnostic tests useful for each episode of pneumonia in children.     

Emerging role of Mycoplasma pneumoniae and Chlamydia pneumoniae in paediatric respiratory-tract infections

Increased use of specialised diagnostic techniques over the past 10 years has allowed considerable new information to be obtained concerning Mycoplasma pneumoniae and Chlamydia pneumoniae infections. In children, these pathogens seem to have a more important role in causing respiratory-tract infections than previously thought; they have been associated with wheezing, and they are also frequent in children aged under 5 years. Contrary to original belief, no clinical, laboratory, or radiological findings seem to be unique to M. pneumoniae or C. pneumoniae; furthermore, there is no rapid and cost-effective diagnostic test capable of identifying these pathogens. Appropriate antimicrobial treatment of the infections they cause is needed to reduce the recurrent episodes of wheezing and other respiratory symptoms, to decrease morbidity, and to avoid the spread of the pathogens. However, a number of therapeutic issues remain unsolved.     

Surveillance of Mycoplasma pneumoniae infections in Scotland 1986-1991.

Mycoplasma pneumoniae is the second most common cause of community-acquired pneumonia. Infection is found worldwide and epidemics are said to occur in 4-yearly cycles. In Scotland this pattern has been noted since 1982 and, in common with England and Wales as well probably as other parts of Europe, there is a current epidemic which began in the autumn of 1990. The disease has been noted predominantly in children and young adults, with lower respiratory tract infection as the most common manifestation. At present, diagnosis is based on a serological response and various tests are available for detecting both primary infection and reinfection. In view of the present epidemic, initial treatment of respiratory-tract infection, especially in children and young adults, should include adequate cover against Mycoplasma pneumoniae.     

Role of Mycoplasma pneumoniae and Chlamydia pneumoniae in children with community-acquired lower respiratory tract infections.

In order to evaluate the role of Mycoplasma pneumoniae and Chlamydia pneumoniae, we studied 613 children aged 2-14 years who were hospitalized for community-acquired lower respiratory tract infections (LRTIs). The patients were enrolled in the study by 21 centers in different regions of Italy from May 1998 through April 1999. Paired serum samples were obtained on admission and after 4-6 weeks to assay the titers of M. pneumoniae and C. pneumoniae antibodies. Nasopharyngeal aspirates for the detection of M. pneumoniae and C. pneumoniae were obtained on admission. Acute M. pneumoniae infections in 210 patients (34.3%) and acute C. pneumoniae infections in 87 (14.1%) were diagnosed. Fifteen of the 18 children with M. pneumoniae and/or C. pneumoniae infections whose treatments were considered clinical failures 4-6 weeks after enrollment had not been treated with macrolides. Our study confirms that M. pneumoniae and/or C. pneumoniae plays a significant role in community-acquired LRTIs in children of all ages and that such infections have a more complicated course when not treated with adequate antimicrobial agents.     

Immunologic responses in patients with Mycoplasma pneumoniae infections

Serum concentrations of IgM and IgG antibodies in patients with Mycoplasma pneumoniae pneumonia were determined by means of the enzyme-linked immunosorbent assay. Analysis of serum specimens by treatment with protein A followed by fractionation on sucrose density gradient revealed for the first time the presence of rheumatoid factor in M. pneumoniae pneumonia with a remarkably high frequency. Development and persistence of the rheumatoid factor during the clinical course of this disease were also examined.     

Central nervous system manifestations of Mycoplasma pneumoniae infections

Mycoplasma pneumoniae infection is associated with several manifestations from the central nervous system (CNS) such as encephalitis, aseptic meningitis, acute transverse myelitis, stroke, and polyradiculopathy. In the current paper epidemiologic, clinical, laboratory and treatment data on these manifestations are reviewed. The M. pneumoniae induced immune dysregulation and its contributing role in the pathogenesis of neurological insult is discussed. The recent introduction in clinical practice of newer molecular diagnostic techniques has helped in establishing a firmer association between M. pneumoniae infection and CNS disease especially encephalitis. Clinicians should be aware of the potential association between M. pneumoniae infection and several CNS manifestations. The role of various anti-microbial or immunomodulating therapies in treating such manifestations should be further explored.