Incidence of community-acquired pneumonia in children caused by Mycoplasma pneumoniae: serological results of a prospective, population-based study in primary health care

OBJECTIVE: The objective of the present study was to assess the incidence of community-acquired pneumonia (CAP) in children caused by Mycoplasma pneumoniae. METHODOLOGY: During 12 months in 1981-1982, all CAP cases in a defined child population were registered. M. pneumoniae aetiology, initially measured by complement fixation (CF) test, was in 1999 supplemented by measurement of IgG and IgM antibodies using enzyme immunoassays (EIA). RESULTS: M. pneumoniae was detected in 61 (30%) of 201 paediatric CAP cases, being the most common aetiological agent in those 5 years of age or over. At that age, M. pneumoniae was responsible for over 50% of cases, and over 90% of mycoplasmal cases were treated as outpatients. The EIA detected 17 new cases over and above the 44 detected by CF, while CF alone revealed 10 cases. The incidence of M. pneumoniae CAP increased with age, being over 10/1000 children at the age of 10 years or more. Co-infections with Streptococcus pneumoniae and Chlamydia pneumoniae were present in over 30% and 15%, respectively, of mycoplasmal CAP cases. CONCLUSION: M. pneumoniae is a common cause of paediatric CAP in primary health care, and co-infections with S. pneumoniae are common. Both S. pneumoniae and M. pneumoniae should be taken into account when starting antibiotics for children with CAP.     

Chlamydia pneumoniae infections in patients with community-acquired pneumonia in Slovenia

It is well known that Chlamydia pneumoniae is an important respiratory pathogen. In this study, the prevalence of specific antibodies to C. pneumoniae in hospitalized patients with community-acquired pneumonia (943 adult females, 990 adult males and 185 children) was evaluated over a period of 7 y (1993-99). Two serum samples were obtained from all of the patients: 1 on admission and the other 3 weeks later. The specimens were tested for C. pneumoniae IgG, IgM and IgA antibodies by means of a microimmunofluorescence test. Acute infection with C. pneumoniae was determined in 9.4% of females and 13.1% of males. In children and adolescent patients, the microimmunofluorescence test showed recent infection in 8.6% of cases, with the highest prevalence occurring in the 11-15 y age group. The highest prevalence of C. pneumoniae pneumonia was found in 1995 and 1999: 15.4% and 13.6% respectively. The results obtained showed that C. pneumoniae is persistently present in the population of Slovenia.     

Mycoplasma pneumoniae and Legionella pneumophila in community-acquired lower respiratory tract infections among hospitalized children: diagnosis by real time PCR

Mycoplasma pneumoniae and Legionella pneumophila are increasingly recognized as important agents of community-acquired lower respiratory tract infections (LRTI). Mycoplasma pneumoniae has been also recognized as a cause of nosocomial infections. The aim of this study was to investigate the role of real time polymerase chain reaction (PCR) for the rapid diagnosis of these infections among hospitalized children with community-acquired LRTI. During 2001, 65 children were prospectively studied. Microbiological investigation consisted of capillary PCR with a LightCycler for M. pneumoniae and L. pneumophila in induced sputum or throat swab specimens, IgM enzyme immunoassay for M. pneumoniae and immunofluorescence for L. pneumophila in paired sera. Serology testing showed acute M. pneumoniae infection in 18 (27.5%) patients and L. pneumophila in 1 (1.5%). M. pneumoniae was also detected in sputum specimen by capillary PCR in 9 (50%) serologically diagnosed cases, including 4 (22%) with non-diagnostic IgM levels in the acute phase. Capillary PCR and IgM enzyme immunoassay diagnosed together 15 (83%) M. pneumoniae cases in the acute phase. It is concluded that M. pneumoniae is an important cause of LRTI necessitating hospitalization among children in Greece. Capillary PCR in sputum may diagnose M. pneumoniae LRTI in the acute setting and direct therapy and isolation of patients.     

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.     

A case of pneumonia due to coinfection by Mycoplasma pneumoniae and Chlamydia pneumoniae]

Few cases of Mycoplasma pneumoniae and Chlamydia pneumoniae coinfection in pneumonia have been reported in adults. We report a case of such a double infection in a young adult. A 16-year-old boy was admitted to our hospital with dry cough and fever. Laboratory findings revealed elevated serum GOT and GPT levels. The patient had been administered a beta-lactam antibiotic before admission to our hospital. Antibodies to M. pneumoniae were significantly elevated. Titers of IgM and IgG specific for C. pneumoniae titer were high, as measured by the enzyme-linked immunosorbent assay method. The patient was treated with clarithromycin and discharged after a satisfactory recovery. M. pneumoniae and C. pneumoniae may act as cofactors in community-acquired pneumonia. Further studies are needed to clarify the relationships of these pathogens to community-acquired pneumonia.     

Simkania negevensis in community-acquired pneumonia in Italian children

Simkania negevensis, a recently found Chlamydia-like organism, has been associated with respiratory infections in children and adults with pneumonia, but S. negevensis findings have been common also without any infection. The aims of the present paper were to evaluate S. negevensis in the aetiology of paediatric community-acquired pneumonia (CAP), its seroprevalence in north Italian children, and whether there is cross-reactivity between S. negevensis and Chlamydia pneumoniae serology. Antibodies to S. negevensis were measured by microimmunofluorescence (MIF) in 101 frozen paired sera obtained from children with CAP. Serological evidence (> or =4-fold increase or decrease in IgM or IgG) of acute S. negevensis infection was achieved in 5 (5%) cases. Two were mixed infections with Mycoplasma pneumoniae and 1 with respiratory syncytial virus. In total, 20-30% of the children had measurable antibodies to S. negevensis, with no association with age. No cross-reactivity was observed between antibodies to S. negevensis and C. pneumoniae. S. negevensis appears to be a real, though rare, cause of CAP in children.     

Atypical pathogens in adult patients admitted with community-acquired pneumonia in Korea

This study examined the prevalence of atypical pathogens causing community-acquired pneumonia (CAP) in Korea. We collected sera and clinical data for a period of 1 year for the adult patients consecutively admitted to Chunchon Sacred Heart Hospital with CAP. The diagnosis was made using serologic methods to detect antibodies for Mycoplasma pneumoniae, Chlamydia pneumoniae, Legionella spp., Chlamydia psittaci, and Coxiella burnetii. Among 81 recruited patients, C. pneumoniae (n = 10, 12.3%) was the leading cause of illness, followed by M. pneumoniae (n = 7, 8.6%). One case of C. burnetii pneumonia was detected, but there were no cases of Legionella spp. or C. psittaci. Three cases of C. pneumoniae pneumonia were co-infected with either M. pneumoniae or C. burnetii. There was no significant difference between atypical pneumonia and non-diagnosed pneumonia in terms of clinical manifestations. In conclusion, of the atypical pathogens causing CAP, C. pneumoniae and M. pneumoniae appear to be the important etiologic pathogens in Korea.     

Mycoplasma pneumoniae and Chlamydophila pneumoniae in children with community-acquired pneumonia in Thailand.

BACKGROUND: The prevalence of community-acquired pneumonia (CAP) caused by atypical pathogens in Thai children is unknown. OBJECTIVE: To examine the prevalence of Mycoplasma pneumoniae and Chlamydophila pneumoniae infections in paediatric patients (aged 2-15 years) with CAP in three academic hospitals using standardised laboratory techniques. The characteristics of atypical pneumonia were also compared with other causes of CAP. METHODS: Diagnosis of current infection was based on a four-fold or more rise in antibody serum samples or persistently high antibody titres together with the presence of mycoplasmal or chlamydial DNA in secretions. RESULTS: Of 245 patients with CAP, 17.5% of cases were caused by atypical pathogens (M. pneumoniae 14.3%, C. pneumoniae 2.8% and co-infection 0.4%). We also found atypical pathogens in young children aged 2-5 years. The clinical and laboratory findings did not distinguish atypical pneumonia from other CAPs. Segmental or lobar consolidation on chest X-rays was more common in atypical pneumonia, while dyspnoea was more prominent in other CAPs. CONCLUSION: Our data show a high prevalence of M. pneumoniae and C. pneumoniae in Thai children with CAP, including in children aged 2-5 years.     

Diagnostic utility of the polymerase chain reaction for the diagnosis of Mycoplasma pneumoniae in elderly patients with community-acquired pneumonia

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP) in children and young adults, but limited information about its prevalence in the elderly is available. The polymerase chain reaction (PCR) with primers targeting the cytadhesine P1 gene and the 16S rRNA gene was analyzed for detecting M. pneumoniae in throat washings of 84 patients, aged 60-96 years, with clinical diagnosis of CAP, from September 2002 through August 2004, in Santiago, Chile. PCR results were compared with serology performed by indirect immunofluorescence (IFI). Specimens from 11 of 84 patients (13.1%) were positive for M. pneumoniae by any test. The IFI test was positive in 8 (72.7%) patients and PCR in 7 (63.6%) cases. The acute phase sera allowed diagnosis of M. pneumoniae in 5 of 11 patients (45.4%), 4 of them showing an IgM response. PCR was negative in 4 patients with positive serology and 3 patients were positive only by PCR. The two PCR primers showed 100% correlation, and a similar sensitivity; no inhibitory specimens for PCR were detected. In conclusion, M. pneumoniae should be considered as a potential etiologic agent of CAP in the elderly. Its detection must be performed by a combination of PCR and serology.     

Is it possible to distinguish between atypical pneumonia and bacterial pneumonia?: evaluation of the guidelines for community-acquired pneumonia in Japan

The Japanese Respiratory Society (JRS) published the guidelines for the management of community-acquired pneumonia in 2000. The guidelines set up nine parameters and criteria for the differential diagnosis of atypical pneumonia and bacterial pneumonia based on clinical symptoms, physical signs and laboratory data. To evaluate the performance of these guideline criteria, 91 cases of Chlamydia pneumoniae (53 cases were pure-C. pneumoniae and 38 cases were mixed-C. pneumoniae pneumonia), 103 cases of Mycoplasma pneumoniae (86 cases were pure-M. pneumoniae and 17 cases were mixed-M. pneumoniae pneumonia) and 144 cases of bacterial (Streptococcus pneumoniae and/or Haemophilus influenzae) pneumonia were analyzed. The accordance rate for a suspected atypical pneumonia with the guideline criteria was 84.8% for pure-M. pneumoniae pneumonia and 60.3% for pure-C. pneumoniae pneumonia, but only 9.0% for bacterial pneumonia, 12.1% for mixed-C. pneumoniae pneumonia and 16.6% for mixed-M. pneumoniae pneumonia. Overall, the sensitivity and specificity of the criteria in the JRS guidelines were 75.5% and 90.9%, respectively. Our results indicated that the differentiation of pneumonia in the JRS guidelines is useful for the diagnosis of M. pneumoniae pneumonia, but difficult to apply to the diagnosis of C. pneumoniae pneumonia.     

First report on clinical features of Mycoplasma pneumoniae infections in Vietnamese children

Mycoplasma pneumoniae is a common cause of community-acquired pneumonia (CAP) in children, but there has been no clinical report on M. pneumoniae infections in Vietnamese children. We investigated the clinical features of M. pneumoniae infection when the pathogen was detected in the respiratory tract in hospitalized children aged 1-15 years due to lower respiratory tract infections or CAP in Vietnamese children. Throat swabs from 47 patients (18.6%) of 252 patients with a clinical diagnosis of CAP were PCR positive (male, 34; female, 13), and 21 throat swabs (8.3%) showed culture positive for M. pneumoniae. The M. pneumoniae pathogen could be detected by PCR and/or culture in 52 patients (male, 36; female, 16). The major clinical signs in the 52 patients were fever (>38 degrees C) in 100%, pharyngitis in 100%, tachypnea in 94%, dry cough in 86.5%, and rough breathing in 83% of patients. The average term of illness prior to hospitalization was 7.5+/-4.1 days, and the average number of hospitalized days was 7.9+/-3.5 days. Beta-lactam group antibiotics, which were ineffective against M. pneumoniae infection, were used in 37 cases (71%).     

Nonsevere community-acquired pneumonia: correlation between cause and severity or comorbidity

BACKGROUND: Community-acquired pneumonia frequently constitutes a nonsevere infection manageable at home. However, for these low-risk episodes, the epidemiological features have not been carefully analyzed. OBJECTIVES: To determine the cause of nonsevere community-acquired pneumonia and to investigate if a correlation exists between cause and severity or comorbidity. METHODS: During a 3-year period, all patients with nonsevere community-acquired pneumonia, according to the Pneumonia Patient Outcome Research Team prognostic classification (patients in groups 1-3), were included in the study. Causes were investigated through the following procedures: cultures of blood, sputum, and pleural fluid; serologic tests; and polymerase chain reaction methods to detect Streptococcus pneumoniae DNA in whole blood or Mycoplasma pneumoniae and Chlamydia pneumoniae DNA in throat swab specimens. RESULTS: Of 317 initially included patients, 247 were eligible for the study. A microbial diagnosis was obtained in 162 patients (66%), and the main pathogens detected were S pneumoniae (69 patients [28%]), M pneumoniae (40 patients [16%]), and C pneumoniae (28 patients [11%]). For the 58 patients in prognostic group 1, M pneumoniae was the most prevalent cause, and atypical microorganisms constituted 40 (69%) of the isolated agents. In contrast, for patients in prognostic groups 2 and 3, S pneumoniae was the leading agent, and a significant reduction of M pneumoniae cases and a greater presence of other more uncommon pathogens were observed. The existence of comorbid conditions was not a determining factor for particular causes. CONCLUSIONS: Among low-risk patients with community-acquired pneumonia, there was a certain correlation between severity and cause. In contrast, the existence of a comorbidity did not have a predictive causative value.     

Chlamydia pneumoniae and Mycoplasma pneumoniae

Mycoplasma pneumoniae infection occurs worldwide and is the most common cause of community-acquired pneumonia (CAP) in 5- to 20-year-olds. The most reliable diagnostic test is the enzyme immunoassay, which allows immunoglobulin (Ig)G and IgM titration and presents 92% sensitivity and 95% specificity on paired samples. Potentially active drugs are tetracyclines, macrolides, ketolides, lincosamides, streptogamines, chloramphenicol, and fluoroquinolones. Chlamydia pneumoniae accounts for 6 to 20% of CAP cases, depending on several factors such as setting of the studied population, age group examined, and diagnostic methods used. The current gold standard for serological diagnosis of acute infection is microimmunofluorescence testing. Tetracyclines and erythromycin show good in vitro activity and so far have been the most commonly employed drugs in the treatment of C. pneumoniae infection. New macrolides, ketolides, and new fluoroquinolones are other potentially effective drugs.     

Chlamydia pneumoniae in community-acquired pneumonia: seven years of experience

OBJECTIVES: To determine the prevalence of Chlamydia pneumoniae in community-acquired pneumonia during a period of seven years. METHODS: Serum samples from 311 patients with pneumonia were evaluated using microimmunofluorescence assay to detect C. pneumoniae -specific IgG and IgM antibodies. RESULTS: Thirty nine patients (12.5%) complied with the diagnostic criteria of acute C. pneumoniae infection (a four-fold rise in the titer of IgG antibody, or a single IgG titer > or = 1:512, or a single IgM titer > or = 1:16). All patients were diagnosed as having pneumonia. Co-infection with other respiratory tract pathogens was found in four patients. CONCLUSIONS: C. pneumoniae is an important cause of pneumonia also in our area. Pneumonia due to this bacterium occurs in the cold months and in early spring; in addition we have observed periods of increased incidence of one years duration and periods of low incidence lasting one-two years. Therapy with macrolides and levofloxacin was effective in all patients with C. pneumoniae infection.     

Multicenter screening of Chlamydia pneumoniae pneumonia by ELISA method

We prospectively investigated the etiology of community-acquired pneumonia among adult patients admitted to three general hospitals over one year. Antibody titers to Chlamydia pneumoniae were also measured by ELISA method to investigate the incidence and clinical pictures of C. pneumoniae pneumonia in Japan. Two hundred and fourteen patients were enrolled in the study. Seventeen patients (7.9%) satisfied the criteria for diagnosis of acute infection due to C. pneumoniae by ELISA method. C. pneumoniae was the 3rd leading causative agent following Streptococcus pneumoniae (21.5%) and Haemophilus influenzae (8.4%). Preexisting antibodies were detected in 62.1% of the patients. Most of the patients with C. pneumoniae pneumonia were aged, and had comorbidities of respiratory system. Superinfection with bacterial pneumonia was recognized in some patients. Though there are several problems, ELISA method is thought to be useful to diagnose C. pneumoniae pneumonia, and is suitable for screening tests.     

Epidemiology, clinical characteristics and antimicrobial resistance patterns of community-acquired pneumonia in 1702 hospitalized children in Singapore

OBJECTIVE AND BACKGROUND: Childhood community-acquired pneumonia (CAP) remains a leading cause of morbidity and mortality worldwide. The features of childhood CAP vary between countries. The aim of this study was to delineate the clinical characteristics, complications, spectrum of pathogens and patterns of antimicrobial resistance associated with hospitalized cases of childhood CAP in Singapore. METHODS: A retrospective study was conducted of patients discharged from Singapore's only children's hospital over a 3-year period with a principal diagnosis of CAP. RESULTS: A total of 1702 children, with a median age of 4.2 years (range: 1 month-16.3 years) were enrolled. A pathogen was identifiable in 38.4% of cases, including Mycoplasma pneumoniae in 20.3%, typical respiratory bacteria in 10.3% (64.6%Streptococcus pneumoniae; 21.7% non-typeable Haemophilus influenzae), viruses in 5.5% and mixed bacterial/viral infections in 2%. The majority of M. pneumoniae infections were in school-aged children (>5 years). Severity of infection was greater in CAP caused by typical bacteria, as reflected by length of hospital stay, CRP level, white cell and absolute neutrophil counts. Mortality from typical bacterial infections (8.9%) exceeded that from M. pneumoniae (0.3%) and viral pneumonias (0%) (P < 0.001). Aminopenicillins were often prescribed empirically for suspected S. pneumoniae and H. influenzae infections; however, resistance to these agents was frequently documented among S. pneumoniae (58.5%) and H. influenzae isolates (51%). CONCLUSION: In Singaporean children hospitalized with CAP, M. pneumoniae is the most commonly identified causative organism, followed by common respiratory viruses, S. pneumoniae and H. influenzae. Streptococcus pneumoniae and H. influenzae are associated with greater severity of infection than other organisms, and have high levels of resistance to commonly prescribed antibiotics.     

Mycoplasma pneumoniae infections

Mycoplasma pneumoniae is a frequent cause of community-acquired respiratory infections in children and adults. Although the organism is felt to be the most frequent 'atypical' pathogen responsible for community-acquired pneumonia in adults, the prevalence of M. pneumoniae varies greatly from study to study, depending on the population and the diagnostic methods used. Recent studies have found the prevalence of M. pneumoniae in adults with pneumonia to range from 1.9 to over 30%. M. pneumoniae is also a frequent cause of outbreaks of respiratory disease in institutional settings. However, the diagnosis of M. pneumoniae infection is hampered by the lack of standardized, rapid, specific methods. This problem was illustrated by the results of an investigation of an outbreak of M. pneumoniae infection in a federal training facility. Accurate diagnosis required a combination of polymerase chain reaction and serology, as IgM antibodies were not present early in the course of the infection in many patients. Several papers evaluating various serological and polymerase chain reaction assays were published during the period of this review. An assessment of the actual performance of these tests was also hampered by the lack of standardized comparative methods. M. pneumoniae is susceptible in vitro to macrolides, tetracyclines and quinolone antibiotics; however, data are limited on the microbiological efficacy of these agents. Several pneumonia treatment studies were published during this period, practically all of them based the diagnosis of M. pneumoniae infection on serology; different methods and criteria were used in each study, and thus the microbiological efficacy could not be assessed. The Infectious Disease Society of America recently stated in their revised Practice Guidelines for the Management of Community-Acquired Pneumonia in Adults that, as there were no diagnostic tests available that reliably and rapidly detect M. pneumoniae, therapy must usually be empirical.     

非典型病原菌致成人社区获得性肺炎患者的临床特点分析

目的 研究非典型病原菌感染在成人住院社区获得性肺炎中的重要地位,并对其临床特点进行分析.方法 收集2005年5月至2008年5月来自国内多中心的153例成人社区获得性肺炎住院患者急性期及恢复期双份血清和急性期痰标本,采用间接免疫荧光法检测肺炎衣原体IgG抗体及嗜肺军团菌IgG、IgA及IgM混合抗体滴度,采用被动凝集法检测肺炎支原体IgG、IgA及IgM混合抗体滴度,同时对153份急性期痰标本进行普通细菌培养.用回顾性分析方法了解非典型病原菌在成人社区获得性肺炎住院患者中的地位.结果 153例血清学检测结果中符合非典型病原菌致社区获得性肺炎诊断标准的52例(34.0%),其中47例为单一非典型病原菌感染,其中肺炎衣原体38例,肺炎支原体4例,嗜肺军团菌5例;5例为2种非典型病原菌混合感染,其中肺炎衣原体+肺炎支原体2例,肺炎衣原体+嗜肺军团菌3例;52例中合并细菌感染者11例.结论 非典型病原菌(肺炎衣原体、肺炎支原体及嗜肺军团菌)为成人住院社区获得性肺炎的重要致病菌,以肺炎衣原体为主,同时不能忽视合并细菌感染情况的存在.     

Clinical presentation of community-acquired Chlamydia pneumoniae pneumonia in adults

STUDY OBJECTIVE: To investigate the clinical presentation of community-acquired Chlamydia pneumoniae pneumonia in adults. DESIGN: Prospective study. SETTING: Kawasaki Medical School Hospital, Kawasaki Medical School Kawasaki Hospital, and Kurashiki Daiichi Hospital in Japan. PARTICIPANTS: Forty patients with community-acquired pneumonia with C pneumoniae as the only pathogen identified admitted to three hospitals between April 1996 and March 2001 and their clinical presentations were compared to patients with Streptococcus pneumoniae and Mycoplasma pneumoniae pneumonia. MEASUREMENTS: The diagnosis of C pneumoniae infection was based on isolation and serologic testing of antibodies by the microimmunofluorescence test. RESULTS: The clinical presentations, except for shortness of breath, were similar for the three major etiologic agents. The mean temperature of C pneumoniae patients on hospital admission was 37.9 degrees C, which was lower than that of patients with S pneumoniae and M pneumoniae. The mean WBC count on hospital admission was lower in the patients with C pneumoniae (mean, 9,100/microL) than in those with S pneumoniae pneumonia but higher than in those with M pneumoniae pneumonia. No patients required respiratory support or admission to an ICU, and no deaths occurred among the C pneumoniae pneumonia patients. CONCLUSIONS: Our results indicate that C pneumoniae pneumonia as a single etiologic agent is mild and that the underlying conditions and clinical symptoms closely resemble those of S pneumoniae pneumonia. However, the physical examinations, laboratory findings, and prognostic factors of the C pneumoniae patients resembled those of patients with M pneumoniae pneumonia.