Chlamydia pneumoniae and Mycoplasma pneumoniae in young children from China with community-acquired pneumonia

A retrospective study of azithromycin and ceftizoxime for the management of children with Mycoplasma pneumoniae pneumonia

The aim of this study was to compare the clinical efficacy of azithromycin and ceftizoxime (AC) and erythromycin and amoxicillin/sulbactam (EAS) in the treatment of children with Mycoplasma pneumoniae pneumonia (MPP).In this retrospective study, a total of 92 eligible children with MPP were included, and they were divided into a treatment group (n = 46) and a control group (n = 46). All patients were treated with intravenous ambroxol, and nebulized inhalation of budesonide and terbutaline. In addition, patients in the treatment group received AC. Patients in the control group underwent EAS. All patients in both groups were treated for a total of 10 days. Outcomes consist of erythrocyte sedimentation rate, C-reactive protein, serum lactate dehydrogenase, and interleukin 6, fever clearance time, time of cough disappearance, time of rale disappearance, time of signs disappeared by X-ray, and adverse events. All outcomes were measured after 10-day treatment.After treatment, patients who received AC exerted better improvements in erythrocyte sedimentation rate (P < .01), C-reactive protein (P < .01), serum lactate dehydrogenase (P < .01), interleukin 6 (P < .01), fever clearance time (P < .01), time of cough disappearance (P < .01), time of rale disappearance (P < .01), and time of signs disappeared by X-ray (P < .01), than those in patients who received EAS. In addition, there were not significant differences in adverse events between 2 groups.The results of this study showed that AC may benefit more than EAS for the children with MPP.

Designing of an epitope-based peptide vaccine against walking pneumonia: an immunoinformatics approach

Mycoplasma pneumoniae is a substantial respiratory pathogen that develops not only pneumonia but also other respiratory diseases, which mimic viral respiratory syndromes. Nevertheless, vaccine development for this pathogen delays behind as immunity correlated with protection is now predominantly unknown. In the present study, an immunoinformatics pipeline is utilized for epitope-based peptide vaccine design, which can trigger a critical immune response against M. pneumoniae. A total of 105 T-cell epitopes from 12 membrane associated proteins and 7 T-cell epitopes from 5 cytadherence proteins of M. pneumoniae were obtained and validated. Thus, 18 peptides with 9-mer core sequence were identified as best T-cell epitopes by considering the number of residues with > 75% in favored region. Further, the crucial screening studies predicted three peptides with good binding affinity towards HLA molecules as best T-cell and B-cell epitopes. Based on this result, visualization, and dynamic simulation for the three epitopes (WIHGLILLF, VILLFLLLF, and LLAWMLVLF) were assessed. The predicted epitopes needs to be further validated for their adept use as vaccine. Collectively, the study opens up a new horizon with extensive therapeutic application against M. pneumoniae and its associated diseases.

The clinical characteristics of corticosteroid-resistant refractory Mycoplasma Pneumoniae pneumonia in children

To analyze the clinical characteristics of corticosteroid-resistant refractory Mycoplasma pneumoniae pneumonia (RMPP) and explore the related factors that predict corticosteroid-resistant RMPP. Retrospective analysis of 183 children with RMPP in our hospital admitted between January 1, 2012, and December 31, 2014 was performed. Of the 183 RMPP cases, 36 (19.7%) were corticosteroid-resistant RMPP cases. Corticosteroid-resistant RMPP cases had a longer duration of fever and hospitalization compared with corticosteroid-sensitive RMPP cases (P < 0.05). The radiographic findings of 123 (83.7%) cases of corticosteroid-sensitive RMPP apparently resolved after one week of corticosteroid treatment compared with 4 (11.1%) corticosteroid-resistant RMPP cases that had apparently resolution (P < 0.01). Twenty-four (75%) corticosteroid-resistant RMPP patients who received bronchoscopy had mucus plug formation while none of the corticosteroid-sensitive RMPP patients had mucus plug formation (P < 0.05). Multiple logistic regression analysis showed that duration of fever ≥11 days, percentage of lymphocytes ≤32%, CRP ≥48.73 mg/L and LDH ≥ 545.7 U/L were significant predictors of corticosteroid-resistant RMPP. Patients with corticosteroid-resistant RMPP had more severe presentations and more serious radiological findings. Clinicians might use the parameters of duration of fever, CRP, LDH and proportion of lymphocytes to identify children at higher risk of corticosteroid-resistant RMPP.

Study of Two Separate Types of Macrolide-Resistant Mycoplasma pneumoniae Outbreaks

To study the complete natural process of a Mycoplasma pneumoniae outbreak in a semiclosed room such as a primary school room, we investigated two separate M. pneumoniae outbreaks involving 81 students in total in two primary schools in Hangzhou, China. M. pneumoniae isolates from pharyngeal swabs were detected by fluorescence quantitative real-time PCR (RT-PCR) and culture. The class in school M had 39 students, with 12 (30.8%) with positive M. pneumoniae detection results. The class from school J had 42 students, with 13 (31.0%) positive. The strains from two classes were confirmed to represent two clones (3/4/5/7/2 and 5/4/5/7/2) and to be macrolide resistant (A2063G) according to P1 and multilocus variable-number tandem-repeat analysis (MLVA) genotyping, determination of MIC of antibiotics, and sequencing. Students with M. pneumoniae isolates detected were divided into three groups: those carrying the isolates, those with upper respiratory tract infection (URI), and those with pneumonia. Longitudinal sampling performed using pharyngeal swabs showed that the persistence of M. pneumoniae was longest in the group of students with pneumonia. M. pneumoniae causes pneumonia outbreaks in schools, and the incidence of pneumonia has a higher rate than that of URI. The persistence of M. pneumoniae, with a median duration of 79.50 days in the group of students with pneumonia, differs from that of the infection state.

Epidemiology of community-acquired pneumonia and implications for vaccination of children living in developing and newly industrialized countries: A systematic literature review

This systematic review evaluated the epidemiology of community-acquired pneumonia in children <6 y of age within 90 developing and newly industrialized countries. Literature searches (1990–2011), based on MEDLINE, EMBASE, Cochrane, CAB Global Health, WHO, UNICEF, country-specific websites, conferences, health-technology-assessment agencies, and the reference lists of included studies, yielded 8,734 records; 62 of 340 studies were included in this review. The highest incidence rate among included studies was 0.51 episodes/child-year, for children <5 y of age in Bangladesh. The highest prevalence was in Chinese children <6 months of age (37.88%). The main bacterial pathogens were Streptococcus pneumoniae, Haemophilus influenzae and Mycoplasma pneumoniae and the main viral pathogens were respiratory syncytial virus, adenovirus and rhinovirus. Community-acquired pneumonia remains associated with high rates of morbidity and mortality. Improved and efficient surveillance and documentation of the epidemiology and burden of community-acquired pneumonia across various geographical regions is warranted.

Epidemiology and clinical features of segmental/lobar pattern Mycoplasma pneumoniae pneumonia: A ten-year retrospective clinical study

Mycoplasma pneumoniae plays an important role in community-acquired pneumonia. However, epidemiological and clinical studies on the segmental/lobar pattern (S/L) radiographic-pathologic subtype of pediatric Mycoplasma pneumoniae pneumonia (MPP) are rare. The current study retrospectively analyzed the epidemiological and clinical characteristics of pediatric MPP patients. A total of 1,933 children with MPP received treatment at a single hospital between 2000 and 2009, of which 684 (35.4%) were diagnosed with S/L-MPP. The annual incidence of S/L-MPP in children with MPP increased throughout the duration of this study (from 6.4 to 59.6%, P<0.001), which was particularly evident after 2003. S/L-MPP was predominantly found in pre-school-aged children (4-6 years old; 56.6%). Compared with non-S/L-MPP, S/L-MPP was more closely associated with severe manifestations, including higher rates of fever (90.2 vs. 83.3%), pleural effusion (3.9 vs. 1.3%), extrapulmonary manifestations (26.2 vs. 21.2%), abnormal white blood cell counts (65.5 vs. 55.2%), abnormal C-reactive protein levels (30.9 vs. 23.7%) and bacterial co-infection (32.0 vs. 24.9%), as well as longer durations of fever (4.13±4.28 vs. 3.02±2.22 days) and hospitalization (12.70±4.54 vs. 9.22±5.12 days). Older S/L-MPP patients showed higher rates and longer durations of fever and cough; however, they also displayed a lower rate of extrapulmonary manifestations when compared with younger patients. In conclusion, the annual incidence of S/L-MPP has increased in recent years. Pre-school-aged children (4-6 years) with MPP are more likely to display a segmental/lobar pattern, which is associated with more severe clinical manifestations than other MPP infection patterns.

Antibody responses of Chlamydophila pneumoniae pneumonia: Why is the diagnosis of C. pneumoniae pneumonia difficult?

The ELNAS Plate Chlamydophila pneumoniae commercial test kit for the detection of anti-C. pneumoniae-specific immunoglobulin M (IgM), IgA and IgG antibodies has become available in Japan recently. To determine the optimum serum collection point for the ELNAS plate in the diagnosis of C. pneumoniae pneumonia, we analyzed the kinetics of the antibody response in patients with laboratory-confirmed C. pneumoniae pneumonia. We enrolled five C. pneumoniae pneumonia cases and collected sera from patients for several months. The kinetics of the IgM and IgG antibody responses were similar among the five patients. Significant increases in IgM and IgG antibody titer between paired sera were observed in all patients. IgM antibodies appeared approximately 2-3 weeks after the onset of illness, reached a peak after 4-5 weeks, and were generally undetectable after 3-5 months. IgG antibodies developed slowly for the first 30 days and reached a plateau approximately 3-4 months after the onset of illness. The kinetics of IgA antibody responses were different among the five patients, and significant increases in IgA antibody titer between paired sera were observed in only two patients. Although the sample size was small, the best serum collection time seemed to be approximately 3-6 weeks after onset of illness when using a single serum sample for the detection of IgM antibodies. Paired sera samples should be obtained at least 4 weeks apart. IgA antibody analysis using ELNAS may not be a useful marker for acute C. pneumoniae pneumonia.

Diagnostic features of community-acquired pneumonia in children: what's new?

AIM

To critically summarise the available data on diagnosis of CAP in children, focusing on the newest findings and on the need for new studies.

METHODS

Eighty studies on the diagnosis of paediatric community-acquired pneumonia were scrutinised.

RESULTS

We found no significant associations between the signs or symptoms and aetiology of pneumonia and concluded that chest radiographs remain controversial and real-time polymerase chain reaction appears more sensitive than blood cultures.

CONCLUSION

Antibiotic overuse could make it difficult to differentiate viral and bacterial causes. Molecular methods provide promising tools for diagnosing infection by atypical bacteria, but are expensive and should be used selectively.

Vaccine preventable community-acquired pneumonia in hospitalized children in Northwest China

BACKGROUND

Community-acquired pneumonia (CAP) is a major cause of morbidity in industrialized countries and morbidity/mortality in developing countries. In China, comprehensive studies of the etiology of CAP in children aged between 2 months and 14 years who are serious enough to require hospitalization are lacking. Previous studies have been limited in child age range, focused on fatal cases, and/or limited in etiologies sought. An understanding of the etiologies is needed for development of best prevention and management practices.

OBJECTIVE

The aim of this study was to prospectively determine during a 12-month period the etiology of CAP in hospitalized children in a center in Northwest China.

DESIGN/METHODS

A prospective 12-month study (2004-2005) of CAP cases in children who were 2 months to 14 years of age admitted to the Second Hospital of Lanzhou University, China. Testing included admission and 1-month postdischarge serum for viral and bacterial serologic analyses (respiratory syncytial virus, influenza A and B, paraflu 1-3, adenovirus; Streptococcus pneumoniae, Haemophilus influenza B, Mycoplasma, and Moraxella. catarrhalis), blood culture, a nasopharyngeal aspirate for viral antigen testing, and a chest radiograph on admission and 1 month postdischarge. The study was funded by Lanzhou University. The study was performed in compliance with the guidelines of the institutional review board of the Second Hospital of Lanzhou University.

RESULTS

CAP was the admitting diagnosis for 29% of all admissions during the 12-month study. Of the 884 CAP cases, 821 (93%) were enrolled and completed the study. The age range was 2 months to 14 years; mean age was 2.3 years; 40% were <1 year. The average length of stay was 9.2 days (range, 6-20) but varied by age and etiology. Fourteen percent had received antibiotics before admission and 14% had underlying illnesses; 12% required intensive care unit treatment and 5 died. A microbial etiology for CAP was identified in 547 (67%); viral 535 (43%), bacterial 228 (27%), mixed viral bacterial 107 (13%), mixed viral in 1%, and mixed bacterial in 1%. The etiology varied by age; respiratory syncytial virus was most common in <1 year, S. pneumoniae and Hib 1-3 years, and Mycoplasma 5 years. Three potentially vaccine preventable etiologies accounted for 35% of the cases: influenza 9%, Hib 12%, and S. pneumonia 14%.

CONCLUSIONS

CAP is a major cause of childhood admission in China. Given the etiologic findings in this study, potentially 25% to 35% of cases could be prevented if seasonal influenza vaccine and conjugated H. influenza b and conjugated pneumococcal vaccines were introduced into routine practice.

Acute respiratory infection due to Mycoplasma pneumoniae: current status of diagnostic methods

Because of the absence of well-standardized both in-house and FDA-approved commercially available diagnostic tests, the reliable diagnosis of respiratory infection due to Mycoplasma pneumoniae remains difficult. In addition, no formal external quality assessment schemes which would allow to conclude about the performance of M. pneumoniae diagnostic tests exist. In this review, the current state of knowledge of M. pneumoniae-associated respiratory infections in the context of epidemiological studies published during the past 5 years is discussed, with particular emphasis on the diagnostic strategies used and their impact on results. The role of M. pneumoniae as a cause of respiratory tract infections (RTIs) differs from study to study due to geographical and epidemiological differences, as well as to the application of different diagnostic techniques and criteria used.

Comparison of commercial and in-house real-time PCR assays used for detection of Mycoplasma pneumoniae

We tested two commercial and three in-house PCR assays under standardized conditions to detect Mycoplasma pneumoniae. All five procedures were able to demonstrate M. pneumoniae DNA in a concentration comparable to 1 CFU/microl, but the mean crossing points resulted in differences in the concentration of the genome copies of a factor of 20.

Retrospective analysis of Mycoplasma pneumoniae infection in pediatric fatal pneumonia in Guangzhou, South China

The objective of this study is to investigate the infection and distribution of Mycoplasma pneumoniae in autopsied pulmonary tissue of pediatric severe pneumonia. Mycoplasma pneumoniae nested polymerase chain reaction and immunohistochemistry were done on autopsy pulmonary tissue from 173 patients who died of severe pneumonia. Mycoplasma pneumoniae was identified in 135/173 (78.03%) and 114/173 (65.89%) samples of autopsied pulmonary tissue of lethal severe pneumonia via nested polymerase chain reaction and immunohistochemistry, respectively. The coincidence of both assays was 92.4%. Mycoplasma pneumoniae associated fatal pneumonia has showed an increasing trend from 1988 to 2005 in South China, and the fatality rate of Mycoplasma pneumoniae associated fatal pneumonia in infants, 1 to 12 months, has risen to 66.9% (97/145). Mycoplasma pneumoniae is a significant cause of severe pneumonia, it is a universal event in infants, and children have died of severe pneumonia in South China. Mycoplasma pneumoniae might be an important pathogen responsible for fatal pneumonia in Guangzhou area, South China.

Frequency of Chlamydia pneumoniae and Mycoplasma pneumoniae infections in children

OBJECTIVE

Chlamydia pneumoniae and Mycoplasma pneumoniae are among the most important pathogens of acute respiratory infections in children between the ages of 5 and 15 years. We aimed to investigate seasonal frequency of respiratory infections caused by C. pneumoniae and M. pneumoniae, frequency of coinfection, clinical findings and to determine relationship between clinical findings and laboratory results.

MATERIAL AND METHODS

Total of 284 patients (ranging 5-15 years of age), admitted to out-patient clinic with symptoms of respiratory tract infections between January 2004 and June 2005, were enrolled in the study. IgA, IgG and IgM antibodies against C. pneumoniae were quantitatively detected in all serum samples by using microimmunofluorescence (MIF). For the M. pneumoniae infection an IgM titer in the ELISA test were analyzed. Nasopharyngeal smear samples were collected for PCR detection.

RESULTS

Mean age was 8 +/- 2.2 (range 5-14) years. Mycoplasma pneumoniae IgM in 86 (30.2%) cases, C. pneumoniae IgM in one (0.3%) case, IgA in six (2.1%) cases and IgG in 10 (3.5%) cases were found positive. In 10 (3.5%) cases, both C. pneumoniae IgG (a titer of >1/216) and M. pneumoniae IgM were found positive concomitantly. The M. pneumoniae IgM in winter was found significantly higher compared to other seasons. Mycoplasma pneumoniae PCR method was performed on a total of 203 samples in 33 (16.2%) of which M. pneumoniae was found positive. The false positive ratio of PCR technique was found 16.2%. In a total of 217 examined samples by PCR method, the DNA of C. pneumoniae was found positive in two patients.

CONCLUSION

Mycoplasma pneumoniae was a common pathogen in respiratory infections. The otherwise C. pneumoniae infections were rarely seen in children. A Comparison of serology diagnostic tests for M. pneumoniae infections was found more sensitive and specific than PCR.

Sensitive detection of Mycoplasma pneumoniae in human respiratory tract samples by optimized real-time PCR approach

To enhance the sensitivity of the available real-time PCR systems for the detection of Mycoplasma pneumoniae, we established a method to amplify copies of the repetitive element repMp1. In a study of respiratory tract samples, we found that, compared to the use of the conserved part of the P1 adhesin gene as a monocopy target, the use of the repMp1-PCR showed an increase in the detected genome equivalents by a factor of 22.

Acute respiratory infection due to Chlamydia pneumoniae: current status of diagnostic methods

Reliable diagnosis of respiratory infection due to Chlamydia pneumoniae and investigation of its role in chronic diseases remain difficult because of the absence of well-standardized and commercially available diagnostic tests. In 2001, the US Centers for Disease Control and Prevention published recommendations for standardizing the diagnostic approach. In this review, we discuss the current state of knowledge of C. pneumoniae-associated respiratory infections in the context of epidemiological studies published during the past 5 years, with particular emphasis on the diagnostic strategies used and their impact on results. The single most likely factor underlying wide variations in data is the significant interstudy variation of the choice of diagnostic methods and criteria used. Adoption of a more unified approach, both for choices of diagnostic methods and for validation of new molecular assays, is long overdue and will be critically important for development of a standardized test for clinical laboratories.

Identification of risk factors for infection in an outbreak of Mycoplasma pneumoniae respiratory tract disease

BACKGROUND

Mycoplasma pneumoniae is one of the most common pathogens that causes community-acquired respiratory tract infection. Outbreaks are well known, and all age groups are susceptible. An outbreak in an army training unit afforded an opportunity to identify possible risk factors for morbidity.

METHODS

An outbreak of respiratory illness that occurred in a unit comprising 91 trainees was investigated and analyzed as a cohort study. M. pneumoniae infection was suspected on clinical grounds and was confirmed by polymerase chain reaction, culture, and serologic testing. Data regarding medical history, symptoms, signs, and laboratory tests were collected.

RESULTS

During a period of 12 days, 41 soldiers (45.1%) had respiratory illnesses, of which 10 (11.0%) were pneumonia. Comparison of symptomatic and asymptomatic individuals revealed that smoking was associated with higher rates of disease (risk ratio, 2.1; 95% confidence interval [CI], 1.3-3.2; P<.005) and seroconversion (risk ratio, 2; 95% CI, 1.2-3.4; P=.03). In multivariate analysis, both lower acute immunoglobulin G values (adjusted odds ratio, 7.8; 95% CI, 1.4-42.5; P=.018) and smoking (adjusted odds ratio, 5.6; 95% CI, 1.5-20.4; P=.01) were associated with symptomatic infection; stratification according to smoking status revealed that immunoglobulin G levels among nonsmokers were protective. Patients who had pneumonia had lower lymphocyte counts (1400+/-258 vs. 2000+/-465 cells/microL; P=.001).

CONCLUSIONS

Smoking and lower preexisting immunoglobulin G levels were strongly associated with M. pneumoniae respiratory infection. These findings emphasize the importance of immunity and cessation of smoking for the prevention of disease. The high attack rate emphasizes the extent of infection transmission among healthy persons living in close contact.

Office pediatrics: current perspectives on the outpatient evaluation and management of lower respiratory infections in children

PURPOSE OF REVIEW

The outpatient evaluation and management of a child with lower respiratory infection (LRI) remain a challenge to clinicians worldwide. This update will discuss current problems and new developments in the outpatient evaluation and treatment of pediatric LRIs.

RECENT FINDINGS

The cause of pediatric LRIs remains partially defined. Mixed infections and 'unknown' organisms may be important sources of clinical illness. A wider incidence of atypical bacteria LRIs (notably Mycoplasma pneumoniae) in children is now recognized. Viral LRIs from rhinoviruses and human metapneumovirus are increasingly detected in children. Human metapneumovirus may compound the clinical severity of pediatric LRIs, specifically in combination with respiratory syncytial virus. Innovations in testing for viral LRIs offer a promising tool for the outpatient evaluation and management of pediatric LRIs.

SUMMARY

Neither clinical symptoms nor findings on chest radiographs can reliably distinguish children with bacterial LRIs from those with viral or atypical pathogens. The efficacy of outpatient antibiotic treatment of atypical bacteria LRIs remains unproven. Multiplex rapid viral testing may ultimately help to refine strategies for outpatient management. The outpatient treatment of viral LRIs remains limited to supportive care; the 'value' of bronchodilators, epinephrine, or corticosteroids for treatment of bronchiolitis is unconfirmed.