M. pneumoniae respiratory diseases: clinical features--children

Chest X-ray findings were studied in 618 pediatric patients with M. pneumoniae respiratory infections. Of these, 472 (76 percent) had pneumonia. Pneumonia was most frequently observed in the lower lung field and least frequently in the upper lung field. The enlargement of hilar lymph nodes was observed in 34 percent of patients with M. pneumoniae pneumonia in contrast to 5 to 9 percent of patients with pneumonia due to other agents, suggesting that it was rather characteristic of M. pneumoniae pneumonia. It was observed in no patients below one year of age, in 41 percent of those aged one to five years, and then decreased with increase in age. Of children with M. pneumoniae respiratory infections, fever, pneumonia, and positive CF test were less frequently observed in infants below one year, showing that they have slighter symptoms; positive IHA test was less frequently observed and isolation of M. pneumoniae was more frequently observed, as compared to other age groups, among whom these findings were similar. It must be kept in mind, however, that fatal cases of M. pneumoniae pneumonia in infants were reported.     

Cytokines in Mycoplasma pneumoniae infections

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.     

Prevalence of Mycoplasma pneumoniae and Chlamydia pneumoniae in pneumonia patients in four major hospitals in Trinidad

The prevalence of current Mycoplasma pneumoniae and Chlamydia pneumoniae infections in patients with pneumonia in Trinidad, and the relationship between pneumonia and risk factors were investigated. Blood samples were collected from 132 patients diagnosed by attending physicians, as suffering from pneumonia at four hospitals in Trinidad. Serum samples were tested for M. pneumoniae IgM and IgG and C. pneumoniae IgM by the enzyme immunoassay (EIA). In addition, C. pneumoniae IgM and IgG were detected using microimmunofluorescence (MIF). A comprehensive questionnaire which addressed demographic information as well as risk factors for pneumonia was administered to patients. All analyses were done using the Statistical Package for Social Sciences (SPSS), version 9. Seroprevalences of 46.0% (58 of 126) were found for C. pneumoniae Ig M/G, and 66.7% (88 of 132) for M. pneumoniae Ig M/G. The difference was statistically significant (p < 0.01; chi2). Thirty-four percent (43 of 125) for C. pneumoniae Ig M/acute Ig G and 28.8% (36 of 125) of M. pneumoniae IgM were not statistically significant (p > 0.05; chi2). Hospital, gender and ethnicity of patients did not significantly (p > 0.05; chi2) affect the seroprevalence of the bacteria assayed for. However, the prevalence of C. pneumoniae (23.3%) in patients under 21 years old compared to other age groups was statistically significant (p = 0.043; chi2). Overall, the seroprevalence to both pathogens was not significantly (p > 0.05; chi2) affected by comorbidities and signs/symptoms. It was concluded that new infections by C. pneumoniae in pneumonia patients may be an important aetiological agent for the condition in Trinidad.     

Mycoplasmas in diseases of humans.

The roles of Mycoplasma pneumoniae, M. hominis and Ureaplasma urealyticum in diseases of humans are currently under investigation. M. pneumoniae, which causes primary atypical pneumonia, is a well established pathogen of the respiratory tract. Complications of infection by this organism are also being recognized; they include disorders of the hematopoietic, cardiovascular, central nervous, musculoskeletal, cutaneous and gastrointestinal systems. The roles of the genital mycoplasmas M. hominis and U. urealyticum are controversial but may include infections of the genitourinary tract and in pregnancy as well as diseases of the newborn, such as neonatal pneumonia and meningitis. In this review atypical pneumonia due to M. pneumoniae is described and the role of mycoplasmas in other diseases is discussed.     

Assessment of real-time PCR for diagnosis of Mycoplasma pneumoniae pneumonia in pediatric patients

We developed a real-time PCR to detect Mycoplasma pneumoniae with a primer set designed for the 16S rRNA gene. Clinical samples (n=937) were collected from children with community-acquired pneumonia between April 2002 and March 2004 at 12 Japanese medical institutions. Sensitivity of real-time PCR was calculated as 10 colony-forming units per reaction tube using a pMP01 plasmid carrying a 225-bp target DNA fragment of the 16S rRNA gene in M. pneumoniae M129, a standard strain. Results, obtained within 2 h, were compared with those of conventional culture and serologic methods. Of all cases tested, 151 (16.4%) and 129 (13.8%) were positive for M. pneumoniae by real-time PCR and by culture, respectively. Among the 151 cases, almost all of those tested serologically by passive agglutination showed a rise in M. pneumoniae antibody titre between acute and convalescent sera. We conclude that this real-time PCR can identify M. pneumoniae rapidly and fulfills the need for rapid identification, high sensitivity, and high specificity.     

Use of the indirect immunofluorescence test in the diagnosis of an infection, caused by Mycoplasma pneumoniae

The indirect immunofluorescence test has been used for the serodiagnosis of M. pneumoniae infections in two paired blood sera of patients with acute respiratory diseases and acute pneumonia. The optimum methods for obtaining M. pneumonia antigen, its fixation and storage have been determined. The data on the study of the sensitivity, specificity and diagnostic value of the test are presented. The indirect immunofluorescence test has been shown to be capable of the simultaneous detection of complete (complement-binding) and incomplete (not binding the complement) antibodies to M. pneumoniae. This test may be used in the diagnostic practice as a highly sensitive, specific and sufficiently simple serological method.     

Clinical complications of Mycoplasma pneumoniae disease--central nervous system

The mechanism of the neurologic complications associated with primary atypical pneumonia is unknown. To examine the ability of Mycoplasma pneumoniae to enter the brain of experimental animals, the organism was inoculated into adult and suckling mice by various routes. After intranasal infection, M. pneumoniae was isolated from brains and lungs of both groups of mice. After intracerebral inoculation, the high levels of the mycoplasma persisted for two months or more in the brains of suckling mice. In addition, after intravenous infection, the systemic spread of infection occurred in the mice treated with high doses of cyclophosphamide. Our results suggest that M. pneumoniae may be able to reach the brain via blood and it may occur with relative ease in compromised hosts.     

高毒力肺炎克雷伯菌致病及耐药分子机制研究进展

近年来,肺炎克雷伯菌已成为医院内感染及社区获得性感染的常见致病菌,临床标本分离率仅次于大肠埃希菌.根据毒力特征差异,肺炎克雷伯菌可分为经典肺炎克雷伯菌和高毒力肺炎克雷伯菌2种类型.高毒力肺炎克雷伯菌是引起化脓性肝脓肿的主要病原菌,其感染可出现内源性转移,包括眼、肺和中枢神经系统;此外还与原发性肝外感染有关,包括菌血症、...     

Etiology of pneumonia in children in the absence of pneumococcal and antihaemophilus vaccines

Childhood pneumonia represents an important pathology, a cause of morbidity and mortality worldwide. Our study aims to determine etiology of pneumonia in hospitalized children using several laboratory methods. We performed a prospective study that enrolled 560 children age 1 up to 18 years old all diagnosed with pneumonia by clinical and radiological features. We applied various laboratory methods (serologic, bacteriologic: bronchial aspirate, sputum, pleural effusion and blood culture) in order to identify a pathogen agent that caused pneumonia. Statistics used Statistical Package for Social Science. An etiology was established in 68.92% of all cases included in the study, as follows: in 33.93% viral etiology, in 25.13% we identified Streptococcus pneumoniae, in 20.2% Mycoplasma pneumoniae, Klebsiella pneumoniae in 8.29%, Staphylococcus aureus in 7.51%, Haemophilus influenzae in 4.92%. Mixed bacterial and viral infection was identified in 4.40% of all cases. A potential causative agent of childhood pneumonia was determined in most cases, S. pneumoniae being the main agent involved in community acquired childhood pneumonia in our country.     

肺炎克雷伯菌致肝脓肿侵袭综合征3例临床分析及文献复习

为提高对肺炎克雷伯菌感染所致肝脓肿侵袭综合征的临床表现及其危害的认识,回顾性分析3例确诊为肺炎克雷伯菌感染所致肝脓肿患者的临床经过、治疗反应及转归。结果发现3例患者均有肝外播散性病灶,符合肝脓肿侵袭综合征的临床特征。这3例患者为社区获得性感染,均有肝脓肿,其中2例合并眼内炎并造成失明,1例合并腰椎感染、腹主动脉感染及感染性心内膜炎。2例有糖尿病病史,1例免疫正常。结合文献复习,发现肺炎克雷伯菌感染引起肝脓肿及肝外播散性病灶,临床上称为肝脓肿侵袭综合征,大多由高毒力肺炎克雷伯菌引起,好发于糖尿病及免疫缺陷人群,也可发生于免疫正常人群,治疗困难,临床危害严重,需引起重视。     

Community-acquired pneumonia in adults.

Although the frequency of community-acquired pneumonia caused by Streptococcus pneumoniae continues to be high, studies show that Mycoplasma pneumoniae, Chlamydia pneumoniae, or Legionella pneumophila are the etiologic agents in 20% to 40% of community-acquired pneumonia in adults. The clinical presentation of pneumonia caused by these organisms may be indistinguishable from pneumonia due to S pneumoniae. Separation of cases of pneumonia due to S pneumoniae as typical and that caused by M pneumoniae, C pneumoniae, or L pneumophila as atypical is unwarranted and unhelpful in planning therapy. As many as 35% to 50% of patients do not have an etiologic agent identified. Community-acquired pneumonia can have high morbidity and mortality in patients who are older, have underlying lung disease, diabetes mellitus, or other comorbid conditions, or who have decreased immune function regardless of the specific etiologic agent. In choosing appropriate empiric antimicrobial therapy in hosts who are not immunocompromised, erythromycin and other macrolide antibiotics have the advantage of being effective against a wide range of pathogens likely to be encountered, including S pneumoniae, M pneumoniae, and L pneumophila, and of having some benefit against C pneumoniae. In other patients, the selection of antibiotic therapy can be based on age, clinical suspicion, epidemiologic data, and laboratory test results. Antimicrobial therapy can be directed at specific organisms when and if they are identified.     

The incidence of Chlamydia pneumoniae lower respiratory tract infections among university students in northern California.

Chlamydia pneumoniae has recently been identified as a cause of lower respiratory tract infections. From March 1987 to March 1988, 259 university students-151 students with lower respiratory tract infections and 108 controls-from the University of California, Berkeley, were studied to determine the incidence and pattern of C pneumoniae lower respiratory tract infections. Serologic evidence of a recent C pneumoniae infection was found in less than 2%, and the organism was not isolated from any of the subjects. Despite the paucity of evidence of a recent infection, 47.5% of this university population showed serologic evidence of a previous C pneumoniae infection. The lower incidence of C pneumoniae infection in our population, when compared with previous reports, suggests that there may be geographic and temporal differences or fluctuations among populations.     

Electrophoretic and immunologic comparative analysis of Mycoplasma pneumoniae and Mycoplasma genitalium proteins

The Mycoplasma pneumoniae FH strain routinely used in our laboratory for over 25 years as antigen in serological tests, 2 reference M. pneumoniae strains from ATCC (29342 and M129) and 3 isolates of M. pneumoniae obtained in 1995 from pneumonia patients were compared by SDS-PAGE, complement fixation test (CFT) and by Western-immunoblotting against human and rabbit serum samples with high level of mycoplasmal antibodies. On SDS-PAGE all M. pneumoniae strains showed the same number of 23 polypeptides on the gel with identical molecular weights. The same strains on immunoblotting against human and rabbit serum samples showed six bands: 170, 89, 75, 55, 38 and 33 kDa with the strongest antibody staining in 170-(P1 protein) and 89-kDa bands. Because of its known antigenic relationships Mycoplasma genitalium was used for comparison. The pattern of M. genitalium proteins on SDS-PAGE was similar to pattern of M. pneumoniae but distinguishable. On immunoblotting six proteins of M. genitalium (135, 127, 110, 95, 75 and 45 kDa) reacted with human and rabbits immunoglobulins for M. pneumoniae antigens. Furthermore in complement fixation test both antigens, prepared from M. pneumoniae and M. genitalium, reacted as well with human and rabbit immunoglobulins for M. pneumoniae and with rabbit immunoglobulins for M. genitalium. These cross-reactions observed in serological techniques could give false positive results in routine diagnosis of M. pneumoniae infections. In such situations showing on immunoblott of presence in tested serum sample of antibodies to 170- and 89 kDa proteins could confirm M. pneumoniae infection.     

Circulating immune complexes in the diagnosis of Mycoplasma pneumoniae infection

The possibility of detecting M. pneumoniae antigen and antibodies to it, incorporated into immune complexes, in the sera of patients with acute pneumonia by means of erythrocyte diagnosticums was studied, and the immunological characterization of these complexes was made. In patients with mycoplasmal pneumonia M. pneumoniae antigen and specific antibodies, both free and incorporated into immune complexes, were found to circulate in the blood. In children, antigenemia was detected twice as frequently as in adults. Dissociated M. pneumoniae antigens had different molecular weight, their location on the gel chromatogram of the serum being in fractions 7S and 19S. The dissociation of immune complexes permits the detection of M. pneumoniae antigen and antibodies to it in a bound state by means of the passive hemagglutination test, thus increasing the frequency of positive results in the diagnosis of M. pneumoniae infection.     

Human Diseases Associated with Mycoplasmas—With an Appendix on Simple Culture Techniques

The mycoplasmas (formerly called pleuropneumonia-like organisms, or pplo) are a group of pleomorphic micro-organisms characterized by lack of cell wall and ability to form colonies on agar resembling tiny fried eggs. They have been recognized as pathogens of lower mammals since 1898. Of the more than 40 known veterinary species, many are pathogens, commonly causing pneumonia, arthritis or arteritis. Of the mycoplasmas found in man, Mycoplasma pneumoniae is the only well established human pathogen. It is responsible for a variety of respiratory syndromes, of which the most frequently recognized is cold agglutinin-positive atypical pneumonia. Hematologic, neurologic and dermatologic complications of this infection have been noted. M. hominis has been implicated as a causative factor in various febrile complications of pregnancy, such as septic abortion and amnionitis. T-strain mycoplasmas are ubiquitous in the human genitourinary tract, but attempts to link their presence to disease have thus far been unsuccessful. Mycoplasmas also have been associated with neoplastic disease and with rheumatoid arthritis. The validity of these latter findings is unclear, and additional study is needed.     

Induction of pro- and anti-inflammatory molecules in a mouse model of pneumococcal pneumonia after influenza

Mortality after influenza is often due to secondary bacterial pneumonia with Streptococcus pneumoniae, particularly in the elderly. The reasons for the high fatality rate seen with this disease are unclear. To further characterize the pathogenesis of pneumonia after influenza in a mouse model, we examined the pathology and immunology that leads to fatal infection. Influenza-infected mice were either euthanized 24 h after secondary infection with S. pneumoniae for determination of pathology, bacterial cultures, and levels of immune effectors or were followed by use of a live imaging system for development of pneumonia. Influenza-infected mice challenged with each of 3 serotypes of pneumococcus developed a severe, necrotic pneumonia and met endpoints for euthanasia in 24 to 60 h. Strikingly elevated levels of both pro- and anti-inflammatory molecules including interleukins 6 and 10, macrophage inflammatory protein 1alpha, and chemokine KC were present in the blood. High levels of these cytokines and chemokines as well as tumor necrosis factor alpha, interleukin 1beta, and heme oxygenase 1 were present in the lungs, accompanied by a massive influx of neutrophils. Mortality correlated with the development of pneumonia and lung inflammation but not with bacteremia. This model has the potential to help us understand the pathogenesis of severe lung infections.     

High prevalence of Mycoplasma infections among European chronic fatigue syndrome patients. Examination of four Mycoplasma species in blood of chronic fatigue syndrome patients

Prevalence of Mycoplasma species infections in chronic fatigue syndrome (CFS) has been extensively reported in the scientific literature. However, all previous reports highlighted the presence of Mycoplasmas in American patients. In this prospective study, the presence of Mycoplasma fermentans, M. penetrans, M. pneumoniae and M. hominis in the blood of 261 European CFS patients and 36 healthy volunteers was examined using forensic polymerase chain reaction. One hundred and seventy-nine (68.6%) patients were infected by at least one species of Mycoplasma, compared to two out of 36 (5.6%) in the control sample (P<0.001). Among Mycoplasma-infected patients, M. hominis was the most frequently observed infection (n=96; 36.8% of the overall sample), followed by M. pneumoniae and M. fermentans infections (equal frequencies; n=67; 25.7%). M. penetrans infections were not found. Multiple mycoplasmal infections were detected in 45 patients (17.2%). Compared to American CFS patients (M. pneumoniae>M. hominis>M. penetrans), a slightly different pattern of mycoplasmal infections was found in European CFS patients (M. hominis>M. pneumoniae, M. fermentansz.Gt;M. penetrans).     

Serodiagnosis of clinical infections caused by Mycoplasma pneumoniae in Poland in 1970-2010

The aim of the study was evaluation of the reliability of serodiagnosis of mycoplasmosis in Poland after replaced of classical assays, as complement fixation test (CFT) and immunoelectroprecipitation test (IEPT), by the ELISA method. The data were obtained from National Public Health Institute in Warsaw (NPHI), which receives quarterly reports of serologically confirmed infection from Sanitary and Epidemiological Stations through the country. Previously, from the 1970 to 1999 the serodiagnosis in Poland was performed only by uniform CFT using the same M. pneumoniae FH antigen prepared at the Mycoplasma Laboratory of NPHI. The first data of M. pneumoniae serological investigation performed by commercial ELISA, mainly Virotech, which gradually replaced the CFT, were obtained in 2000. In the studied period 1970-2010 a total of over 300 thousand patients with respiratory tract infections (85% were children below 18 years old) were tested. During these studies five epidemics of mycoplasmosis were noted in Poland before 2000. However, after introduction of ELISA for serodiagnosis this characteristic distinct difference in epidemic and endemic occurrence of M pneumoniae infections have not been seen. In our opinion it may be caused by changes in the epidemiological pattern of M. pneumoniae infections in Poland as well as, paradoxical, by the decrease of sensitivity and specificity of serological investigation performed by ELISA since 2000. First of all, for the economical reasons 98% of the patients were tested by ELISA only once, secondly, the mycoplasmosis in many laboratories was confirmed only on the basis of the presence of IgG antibodies. The results of our analysis showed also usefulness in the serodiagnosis of mycoplasmosis, mainly during the first 2 weeks of the disease, of IEPT, which detect only specific IgM antibodies to M pneumoniae antigens.