Mycoplasma pneumoniae in Korean children: The epidemiology of pneumonia over an 18-year period

Investigating the occurrence of autoimmune diseases among children and adolescents hospitalized for Mycoplasma pneumoniae infections

Background

Mycoplasma pneumoniae infection is common in the general population and may be followed by immune dysfunction, but links with subsequent autoimmune disease remain inconclusive.

Objective

To estimate the association of M. pneumoniae infection with the risk of subsequent autoimmune disease.

Methods

This retrospective cohort study examined the medical records of South Korean children from 01/01/2002 to 31/12/2017. The exposed cohort was identified as patients hospitalized for M. pneumoniae infection. Each exposed patient was matched with unexposed controls based on birth year and sex at a 1:10 ratio using incidence density sampling calculations. The outcome was subsequent diagnosis of autoimmune disease, and hazard ratios (HRs) were estimated with control for confounders. Further estimation was performed using hospital-based databases which were converted to a common data model (CDM) to allow comparisons of the different databases.

Results

The exposed cohort consisted of 49,937 children and the matched unexposed of 499,370 children. The median age at diagnosis of M. pneumoniae infection was 4 years (interquartile range, 2.5-6.5 years). During a mean follow-up time of 9.0 ± 3.8 years, the incidence rate of autoimmune diseases was 66.5 per 10,000 person-years (95% CI: 64.3-68.8) in the exposed cohort and 52.3 per 10,000 person-years (95% CI: 51.7-52.9) in the unexposed cohort, corresponding to an absolute rate of difference of 14.3 per 10,000 person-years (95% CI: 11.9-16.6). Children in the exposed cohort had an increased risk of autoimmune disease (HR: 1.26; 95% CI: 1.21-1.31), and this association was similar in the separate analysis of hospital databases (HR: 1.25; 95% CI 1.06-1.49).

Conclusion

M. pneumoniae infection requiring hospitalization may be associated with an increase in subsequent diagnoses of autoimmune diseases.

Epidemiology and surveillance implications of community-acquired pneumonia in children

Community-acquired pneumonia (CAP) is the single largest infectious cause of hospitalization and death in children worldwide. With improved immunizations, the incidence of bacterial pneumonia and the number of colonized bacteria have decreased. However, respiratory viruses are still an important cause of CAP, especially as new infectious agents such severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerge. The SARS-CoV-2 virus emerged in 2019 and caused the current coronavirus disease 2019 pandemic. Therefore, it is necessary to elucidate the epidemiology and causative pathogens of CAP. Recently, the Pneumonia and Respiratory Disease Study Group, affiliated with the Korean Academy of Pediatric Allergy and Respiratory Disease, investigated the causative pathogens of respiratory infections in children hospitalized with CAP, the serotype of Streptococcus pneumoniae, and the prevalence of Mycoplasma pneumoniae with gene mutations. Antibiotic resistance and serotype test results can determine the use of empirical antibiotics. Moreover, it is possible to help develop future vaccines by comparing bacterial culture results with vaccine serotype and identifying the changes and prevalence of each serotype. Therefore, we will perform continuous national surveillance and monitor the epidemiology of respiratory pathogens in Korea and worldwide. The surveillance of these respiratory infections can play a role in monitoring the emergence of new infectious diseases such as SARS-CoV-2.

Assessment of variables associated with prolonged admission duration in children with Mycoplasma pneumoniae pneumonia

Introduction

Macrolide‐resistant Mycoplasma pneumoniae (MRMP) has become prevalent in children. This study investigated the clinical and laboratory variables of MRMP and macrolide‐sensitive M. pneumoniae (MSMP) and identified factors associated with prolonged hospital admission in children.

Methods

A prospective multicenter study was conducted in 1063 children <18 years old in July 2018–June 2020. The 454 had a positive M. pneumoniae polymerase chain reaction assay.

Results

Most subjects had MRMP (78.4%), and all mutated strains had the A2063G transition. We defined MRMP* (n = 285) as MRMP pneumonia requiring admission and MSMP* (n = 72) as MSMP pneumonia requiring admission. Patients with MRMP pneumonia were older, more likely to have segmental/lobar pneumonia, and had more febrile days than those with MSMP pneumonia. C‐reactive protein (CRP), lactate dehydrogenase (LDH), and percentage neutrophils were more strongly associated with MRMP* than MSMP* groups. Percentage neutrophils, CRP, and alanine aminotransferase significantly changed between admission and follow‐up measurements in patients with MRMP* (P < 0.05). The duration of admission positively correlated with the number of febrile days after initiation of antibiotic medication and laboratory variables (white blood cell count, CRP, and aspartate aminotransferase [AST]) (P < 0.05). Random forest analysis indicated that the number of febrile days after initiation of antibiotic medication, AST, and percentage neutrophils at admission was over five.

Conclusions

This study indicated that children with M. pneumoniae pneumonia with a higher number of febrile days after initiation of antibiotic medication, AST, and percentage neutrophils at admission were more likely to have prolonged admission duration.

Epidemic characteristics of Mycoplasma pneumoniae infection: a retrospective analysis of a single center in Suzhou from 2014 to 2020

BACKGROUND

Mycoplasma pneumoniae (M. Pneumoniae) is a common pathogen of respiratory tract infections, but there is still a lack of detailed investigation on the large sample of M. Pneumoniae infection in the all age population. And patients with severe M. Pneumoniae pneumonia (SMPP) still have a certain risk of death. How to identify the clinical characteristics and population of patients with SMPP as soon as possible is still an urgent problem in clinical practice.

METHODS

Demographic characteristics, patient clinical information, and laboratory data of 81,131 patients with respiratory tract infections (RTIs) in the Affiliated Suzhou Hospital of Nanjing Medical University from 2014 to 2020 were retrospectively collected from all patient records. The serum particle agglutination (PA) test was used to determine M. Pneumoniae infection by detecting specific antibodies. The white blood cell count, the proportion of neutrophils and lymphocytes, C-reactive protein (CRP) and lactate dehydrogenase (LDH) levels between children and adults with SMPP were compared by Student's t-test; other clinical features were analyzed by χ² test or Fisher's exact test.

RESULTS

A total of 81,131 patients with RTIs were included, and 21,582 (26.60%) M. Pneumoniae immunoglobulin M (IgM)-positive patients were detected. From 2014 to 2020, the annual proportions of M. Pneumoniae RTIs were 23.60%, 28.18%, 38.08%, 27.05%, 23.44%, 25.26%, and 18.33%, respectively. In terms of seasonal distribution, April-June and September-November were the peak seasons of M. Pneumoniae infection each year. Children and women have a high proportion of M. Pneumoniae infection. The peak age of M. Pneumoniae infection was between 4 and 14 years old. There were 301 cases of SMPP, including 281 children and 20 adults (8 cases of pregnant women). Children and pregnant women accounted for a high proportion of SMPP. Children with SMPP had more extrapulmonary symptoms, multilobar infiltrates, and increased CRP and LDH levels compared with adults.

CONCLUSIONS

M. Pneumoniae infection has seasonal, sex, and age distribution trends. Children and pregnant women accounted for a high proportion of SMPP. Extrapulmonary symptoms, multilobar infiltrates, and increased CRP and LDH levels may be helpful to identify SMPP in children than in adults.

Laboratory analysis of positive rate of Mycoplasma pneumoniae antibody among 53,273 children with respiratory tract infections in Xi'an from 2017 to 2020

BACKGROUND

Mycoplasma pneumoniae (Mp) is an important pathogen that causes respiratory tract infections in children. Data on epidemiology of paediatric Mp infection in China are little known. The aim of this study was to investigate the infection of children with respiratory tract infection in Xi'an from 2017 to 2020, and to explore the epidemiological features of paediatric Mp infection in Northwest China during the past 4 years.

METHODS

A total of 53,273 paediatric patients diagnosed with respiratory tract infection as the first diagnosis were enrolled. Mp antibody was detected using passive agglutination method. Statistical analysis and epidemiological investigation were carried out on the test results according to different years, seasons, ages and genders. The differences among rates were analyzed by the χ² test. The trends among the rates were analyzed by the Poisson regression.

RESULTS

A total of 14,375 Mp antibody positive patients were detected, with a total positive rate of 26.98%. The rate of Mp infection in 2017 was significantly higher than other years (χ²=431.700; P=0.000), and the rate showed a downward trend year by year [incidence rate ratios (IRR) =0.906; 95% CI: 0.892-0.921; P=0.000]. The rate of Mp infection increased gradually in the order of spring, summer, autumn and winter (IRR =1.078; 95% CI: 1.060-1.097; P=0.000), and peaked in winter (29.08%). As age increased, the positive rate of Mp infection also gradually increased (IRR =1.138; 95% CI: 1.134-1.143; P=0.000). The peak age of Mp infection was between 6 and 12 years, accounting for 51.71%, significantly more compared with other age groups (χ²=4203.000, P=0.000). Female children had significantly higher positive rates than male children (χ²=527.000; P=0.000).

CONCLUSIONS

Mp infection mainly occurs related to year, season, age and gender. Understanding the epidemiological characteristics of paediatric Mp infection can contribute to timely treatment and diagnosis, and may improve the prognosis of children with Mp infection.

Analysis of national surveillance of respiratory pathogens for community-acquired pneumonia in children and adolescents

Background

Respiratory infections among children, particularly community-acquired pneumonia (CAP), is a major disease with a high frequency among outpatient and inpatient visits. The causes of CAP vary depending on individual susceptibility, the epidemiological characteristics of the community, and the season. We performed this study to establish a nationwide surveillance network system and identify the causative agents for CAP and antibiotic resistance in Korean children with CAP.

Methods

The monitoring network was composed of 28 secondary and tertiary medical institutions. Upper and lower respiratory samples were assayed using a culture or polymerase chain reaction (PCR) from August 2018 to May 2020.

Results

A total of 1023 cases were registered in patients with CAP, and PCR of atypical pneumonia pathogens revealed 422 cases of M. pneumoniae (41.3%). Respiratory viruses showed a positivity rate of 65.7% by multiplex PCR test, and human rhinovirus was the most common virus, with 312 cases (30.5%). Two hundred sixty four cases (25.8%) were isolated by culture, including 131 cases of S. aureus (12.8%), 92 cases of S. pneumoniae (9%), and 20 cases of H. influenzae (2%). The cultured, isolated bacteria may be colonized pathogen. The proportion of co-detection was 49.2%. The rate of antibiotic resistance showed similar results as previous reports.

Conclusions

This study will identify the pathogens that cause respiratory infections and analyze the current status of antibiotic resistance to provide scientific evidence for management policies of domestic respiratory infections. Additionally, in preparation for new epidemics, including COVID-19, monitoring respiratory infections in children and adolescents has become more important, and research on this topic should be continuously conducted in the future.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-022-07263-z.

Clinical characteristics of children with airway malacia complicated by pneumonia

Background

Airway malacia is an important cause of noisy breathing, recurrent wheezing and respiratory infections, chronic coughing, and episodes of respiratory distress in young children. As the clinical manifestations of airway malacia are not common, many clinicians have insufficient understanding of this disease. So the purpose of this study is to summarize the pathogenic bacteria and clinical manifestations of airway softening complicated with pneumonia in children.

Methods

Children hospitalized with airway malacia complicated by pneumonia were eligible for enrollment from January 1, 2013 to December 31, 2019. Medical records of patients were reviewed for etiology, clinical characteristics, and laboratory examination results.

Results

A total of 164 pneumonia patients with airway malacia were admitted. The male-to-female ratio was 3:1. The age of patients ranged from 1 month to 4 years old. The median age was 6 (3–10) months. The most commonly detected pathogen were Mycoplasma pneumoniae (25/164, 15.24%), Streptococcus pneumoniae (18/164, 10.98%), and respiratory syncytial virus (16/164, 9.76%). Common signs among the 164 patients with confirmed airway malacia included cough (98.78%), wheezing (67.07%), fever (35.37%), intercostal retractions (23.17%), dyspnea (10.98%), cyanosis (11.11%), and crackles (50%). Compared with those without airway malacia, the incidence of premature delivery and mechanical ventilation was higher, and the duration of symptoms before admission (median, 13.5 d) and hospital stay (median 10.0 d) were longer. Of the children with pneumonia, 11.59% of those with airway malacia required supplemental oxygen compared with 4.88% of those without airway malacia (p < 0.05).

Conclusion

The median age of children with airway malacia was 6 months. The most common pathogen in patients with airway malacia complicated by pneumonia was Mycoplasma pneumoniae. Patients with airway malacia complicated by pneumonia often presented with a longer disease course, more severe symptoms, and had delayed recovery.

P1 gene of Mycoplasma pneumoniae isolated from 2016 to 2019 and relationship between genotyping and macrolide resistance in Hokkaido, Japan

We characterized 515 Mycoplasma pneumoniae specimens in Hokkaido. In 2013 and 2014, the p1 gene type 1 strain, mostly macrolide-resistant, was dominant and the prevalence of macrolide resistance was over 50 %. After 2017, the p1 gene type 2 lineage, mostly macrolide-sensitive, increased and the prevalence of macrolide resistance became 31.0 % in 2017, 5.3 % in 2018 and 16.3 % in 2019.

Effect of COVID-19 on childhood Mycoplasma pneumoniae infection in Chengdu, China

BACKGROUND

Following the outbreak of the COVID-19 pandemic, a change in the incidence and transmission of respiratory pathogens was observed. Here, we retrospectively analyzed the impact of COVID-19 on the epidemiologic characteristics of Mycoplasma pneumoniae infection among children in Chengdu, one of the largest cities of western China.

METHOD

M. pneumoniae infection was diagnosed in 33,345 pediatric patients with respiratory symptoms at the Chengdu Women's & Children's Central Hospital between January 2017 and December 2020, based on a serum antibody titer of ≥1:160 measured by the passive agglutination assay. Differences in infection rates were examined by sex, age, and temporal distribution.

RESULTS

Two epidemic outbreaks occurred between October-December 2017 and April-December 2019, and two infection peaks were detected in the second and fourth quarters of 2017, 2018, and 2019. Due to the public health response to COVID-19, the number of positive M. pneumoniae cases significantly decreased in the second quarter of 2020. The number of M. pneumoniae infection among children aged 3-6 years was higher than that in other age groups.

CONCLUSIONS

Preschool children are more susceptible to M. pneumoniae infection and close contact appears to be the predominant factor favoring pathogen transmission. The public health response to COVID-19 can effectively control the transmission of M. pneumoniae.

The risk factors of children acquiring refractory mycoplasma pneumoniae pneumonia: A meta-analysis

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.

Early Confirmation of Mycoplasma pneumoniae Infection by Two Short-Term Serologic IgM Examination

The aim of the present study is to re-evaluate the clinical application of two-times serologic immunoglobulin M (IgM) tests using microparticle agglutination assay (MAA), an enzyme-linked immunosorbent assay (ELISA), and polymerase chain reaction (PCR) assay in diagnosing Mycoplasma pneumoniae (MP) infection. A retrospective analysis of 62 children with MP pneumonia during a recent epidemic (2019–2020) was conducted. The MAA and ELISA immunoglobulin M (IgM) and IgG measurements were conducted twice at admission and around discharge, and MP PCR once at presentation. Diagnostic rates in each test were calculated at presentation and at discharge. The seroconverters were 39% (24/62) of patients tested by MAA and 29% (18/62) by ELISA. At presentation, the diagnostic positive rates of MAA, ELISA, and PCR tests were 61%, 71%, and 52%, respectively. After the second examination, the rates were 100% in both serologic tests. There were positive correlations between the titers of MAA and the IgM values of ELISA. The single serologic IgM or PCR tests had limitations to select patients infected with MP in the early stage. The short-term, paired IgM serologic tests during hospitalization can reduce patient-selection bias in MP infection studies.

Bronchiolitis Associated with Mycoplasma pneumoniae Infection in Infants in Foshan China: An Epidemiologic Study

Background

Bronchiolitis is common in infants under 2 years of age. Most infections are caused by respiratory syncytial virus (RSV), but the importance of Mycoplasma pneumoniae (MP) in the etiology of bronchiolitis is unclear.

Material/Methods

We investigated the clinical characteristics of bronchiolitis caused by MP in 79 infants admitted to Shunde Women’s and Children’s Hospital of Guangdong Medical University and Sanshui Women’s and Children’s Healthcare Hospital from January 2016 to December 2018. Infection with MP was confirmed by the presence of serum immunoglobulin M.

Results

The peak detection rates of MP in the years 2016, 2017, and 2018 were 19.2%, 21.3%, and 24.0%, respectively. In each year, the peak of MP infections occurred during June and July. MP-associated bronchiolitis was mainly seen in infants from 6 to 12 months of age. Compared with RSV-associated bronchiolitis, the age of patients with bronchiolitis associated with MP was significantly older and they had a shorter hospital stay (all P<0.01 or P<0.05).

Conclusions

Our study indicated that MP is an important cause of bronchiolitis, with peaks of occurrence during June and July every year. Pulmonary interstitial infiltration was a characteristic of this infection. Azithromycin treatment can shorten the course of MP-associated bronchiolitis. Investigation of the epidemiological characteristics of pediatric MP-associated bronchiolitis can help diagnose and treat the disease correctly.

The epidemiology of paediatric Mycoplasma pneumoniae pneumonia in North China: 2006 to 2016

Paediatric Mycoplasma pneumoniae pneumonia (MPP) is a major cause of community-acquired pneumonia in China. Data on epidemiology of paediatric MPP from China are little known. This study retrospectively collected data from June 2006 to June 2016 in Beijing Children's Hospital, Capital Medical University of North China and aims to explore the epidemiological features of paediatric MPP and severe MPP (SMPP) in North China during the past 10 years. A total of 27 498 paediatric patients with pneumonia were enrolled. Among them, 37.5% of paediatric patients had MPP. In this area, an epidemic took place every 2-3 years at the peak, and the positive rate of MPP increased during these peak years over time. The peak age of MPP was between the ages of 6 and 10 years, accounting for 75.2%, significantly more compared with other age groups (χ2 = 1384.1, P &lt; 0.0001). The epidemics peaked in September, October and November (χ2 = 904.9, P &lt; 0.0001). Additionally, 13.0% of MPP paediatric patients were SMPP, but over time, the rate of SMPP increased, reaching 42.6% in 2016. The mean age of paediatric patients with SMPP (6.7 ± 3.0 years old) was younger than that of patients with non-SMPP (7.4 ± 3.2 years old) (t = 3.60, P = 0.0001). The prevalence of MPP and SMPP is common in China, especially in children from 6 to 10 years old. Paediatric patients with SMPP tend to be younger than those with non-SMPP. MPP outbreaks occur every 2-3 years in North China. September, October and November are the peak months, unlike in South China. Understanding the epidemiological characteristics of paediatric MPP can contribute to timely treatment and diagnosis, and may improve the prognosis of children with SMPP.

Early Corticosteroid Therapy for Mycoplasma pneumoniae Pneumonia Irrespective of Used Antibiotics in Children

Antibiotics’ effect on Mycoplasma pneumoniae (MP) infection still remains controversial. A prospective study of 257 children with MP pneumonia during a recent epidemic (2015–2016) was conducted. All MP pneumonia patients were treated with corticosteroids within 24–36 h after admission. Initially, oral prednisolone (1 mg/kg) or intravenous methylprednisolone (IVMP; 1–2 mg/kg) was administered for mild pneumonia patients, and IVMP (5–10 mg/kg/day) for severe pneumonia patients. If patients showed a persistent fever for 36–48 h or disease progression, additive IVMP (5 mg/kg or 10 mg/kg) was given. Thirty-three percent of patients received only a broad-spectrum antibiotic without a macrolide. The mean age and the male-to-female ratio was 5.6 ± 3.1 years and 1:1, respectively. Seventy-four percent of patients showed immediate defervescence within 24 h, and 96% of patients showed defervescence within 72 h with improvements in clinical symptoms. Three percent of patients (8/257) who received additive IVMP also showed clinical improvement within 48 h without adverse reactions. There were no clinical or laboratory differences between patients treated with a macrolide (n = 172) and without (n = 85). Early corticosteroid therapy might reduce disease morbidity and prevent disease progression in MP pneumonia patients without side effects, and antibiotics may have limited effects on MP infection.

Clonal Expansion of Macrolide-Resistant Sequence Type 3 Mycoplasma pneumoniae, South Korea

To investigate the genetic background for the emergence of macrolide resistance, we characterized the genetic features of Mycoplasma pneumoniae using multilocus sequence typing. Of the 146 M. pneumoniae strains collected during the 5 consecutive outbreaks of M. pneumoniae pneumonia during 2000–2016 in South Korea, macrolide resistance increased from 0% in the first outbreak to 84.4% in the fifth. Among the 8 sequence types (STs) identified, ST3 (74.7%) was the most prevalent, followed by ST14 (15.1%). Macrolide-susceptible strains comprised 8 different STs, and all macrolide-resistant strains were ST3 (98.3%) except 1 with ST14. The proportion of macrolide-resistant strains in ST3 remained 2.2% (1/46) until the 2006–2007 outbreak and then markedly increased to 82.6% (19/23) during the 2010–2012 outbreak and 95.0% (38/40) during the 2014–2016 outbreak. The findings demonstrated that clonal expansion of ST3 M. pneumoniae was associated with the increase in macrolide resistance in South Korea.

Genetic characterization of Mycoplasma pneumoniae isolated in Osaka between 2011 and 2017: Decreased detection rate of macrolide-resistance and increase of p1 gene type 2 lineage strains

We characterized 419 Mycoplasma pneumoniae isolates collected between 2011 and 2017 in Osaka prefecture of Japan. This analysis revealed high prevalence of macrolide-resistant M. pneumoniae (MRMP) in Osaka during 2011 and 2014 with annual detection rates of MRMP strains between 71.4% and 81.8%. However, in 2015 and after, the detection rate of MRMP decreased significantly and did not exceed 50%. Genotyping of the p1 gene of these isolates showed that most of MRMP strains harbored type 1 p1 gene. In contrast, strains expressing p1 gene type 2 or its variant were largely macrolide-susceptible M. pneumoniae (MSMP) strains. There was a strong correlation between p1 gene genotype and the presence of mutations conferring macrolide resistance in M. pneumoniae isolated in Osaka. These results indicate that lower incidence of MRMP strains in Osaka from 2015 was associated with the relative increase of p1 gene type 2 lineage strains. During these experiments, we also isolated three M. pneumoniae strains that showed irregular typing pattern in the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis of the p1 gene. Two of these strains harbored new variants of type 2 p1 gene and were designated as type 2f and 2g. The remaining strain with an irregular typing pattern had a large deletion in the p1 operon.

Therapeutic Efficacy and Safety of Prolonged Macrolide, Corticosteroid, Doxycycline, and Levofloxacin against Macrolide-Unresponsive Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

We aimed to compare the therapeutic efficacy of prolonged macrolide (PMC), corticosteroids (CST), doxycycline (DXC), and levofloxacin (LFX) against macrolide-unresponsive Mycoplasma pneumoniae (MP) pneumonia in children and to evaluate the safety of the secondary treatment agents.

METHODS

We retrospectively analyzed the data of patients with MP pneumonia hospitalized between January 2015 and April 2017. Macrolide-unresponsiveness was clinically defined with a persistent fever of ≥ 38.0°C at ≥ 72 hours after macrolide treatment. The cases were divided into four groups: PMC, CST, DXC, and LFX. We compared the time to defervescence (TTD) after secondary treatment and the TTD after initial macrolide treatment in each group with adjustment using propensity score-matching analysis.

RESULTS

Among 1,165 cases of MP pneumonia, 190 (16.3%) were unresponsive to macrolides. The proportion of patients who achieved defervescence within 48 hours in CST, DXC, and LFX groups were 96.9% (31/33), 85.7% (12/14), and 83.3% (5/6), respectively. The TTD after initial macrolide treatment did not differ between PMC and CST groups (5.1 vs. 4.2 days, P = 0.085), PMC and DXC groups (4.9 vs. 5.7 days, P = 0.453), and PMC and LFX groups (4.4 vs. 5.0 days, P = 0.283). No side effects were observed in the CST, DXC, and LFX groups.

CONCLUSION

The change to secondary treatment did not show better efficacy compared to PMC in children with macrolide-unresponsive MP pneumonia. Further studies are needed to guide appropriate treatment in children with MP pneumonia.

Increased use of third-generation cephalosporin antibiotics in the outpatient setting in Korean children and adolescents

BACKGROUND

Antimicrobial resistance is a concern to public health, and controlling antibiotic use is therefore important. This study analyzed the trend in outpatient antibiotic prescriptions in children and adolescents in Korea.

METHODS

Using National Prescribing Sample data from the Korea Health Insurance Review and Assessment Service between 1 January 2010 and 31 December 2014, we analyzed outpatient systemic antibiotic (anatomical therapeutic chemical [ATC] J01) prescriptions in patients aged 2-17 years. The antibiotic rate was defined as the proportion of all outpatient prescriptions for antibiotics. We calculated absolute and relative differences with 95%CI between 2010 and 2014 in the antibiotic rate by age group (2-6, 7-11, and 12-17 years) and the percentage of antibiotic prescriptions by antibiotic class. Seven of the most commonly used antibiotic drugs were identified based on defined daily dose.

RESULTS

A total of 7 261 176 prescriptions were written for 1 039 756 pediatric patients between 2010 and 2014. The antibiotic rate in all patients increased from 34.8% in 2010 to 70.4% in 2014, resulting in the relative difference of 102.1% (95%CI: 101.7-102.5). Extended spectrum penicillins were the most commonly prescribed antibiotic class, accounting for 40.0-41.0% of all antibiotic prescriptions. The use of third-generation cephalosporins increased steeply with the relative difference of 55.7% (95%CI: 55.2-56.2). Amoxicillin/clavulanate, an extended spectrum antibiotic drug, was the predominately used antibiotic drug but the use of cefpodoxime, a third-generation cephalosporin, increased by 96%.

CONCLUSIONS

The use of outpatient antibiotics, especially third-generation cephalosporins, has increased in children and adolescents in Korea.

Low-dose versus high-dose methylprednisolone for children with severe Mycoplasma pneumoniae pneumonia (MCMP): Study protocol for a randomized controlled trial

BACKGROUND

Severe Mycoplasma pneumoniae pneumonia (MPP) may develop with long-term pulmonary outcomes despite treatment with macrolides. Combined treatment with glucocorticoids can improve this outcome, though the optimal dosage is unknown. The aim of this study was to investigate the effects of low- and high-dose methylprednisolone in reducing the percentage of long-term pulmonary outcomes for children with severe MPP.

METHODS

A randomized, single-blind, parallel-controlled, multicenter clinical trial, methylprednisolone for children with severe M. pneumoniae pneumonia (MCMP), is being conducted in China. Pediatric patients (≤18 years of age, expected number = 402) admitted to the hospital with a clinical diagnosis of severe MPP and fulfilling inclusion and exclusion criteria are randomized (ratio of 1:1) to either a low-dose (2 mg/kg/d) or high-dose (10 mg/kg/d) methylprednisolone treatment group for 3 days followed by tapering of methylprednisolone over 12 days and combined with azithromycin. The primary composite outcome will be incidence of atelectasis, bronchiectasis, or bronchiolitis obliterans at 6-months after treatment. Secondary outcomes include recovery time of patient temperature, proportion of pulmonary lesions absorbed, changes of mucosa identified by bronchoscopy, length of hospital stay, pulmonary function and number of participant(s) needing intensive care. Assessments will be made at baseline, post-treatment and at 1-month, 3-month and 6-month follow-ups.

DISCUSSION

This is the first randomized clinical trial designed to evaluate the safety and efficacy of low- versus high-dose methylprednisolone for reducing long-term pulmonary outcomes in pediatric patients with severe MPP. The results of this study will provide scientific evidence to guide clinical practice for the treatment of severe MPP. Trial registration: This study is registered at ClinicalTrials.gov (NCT02303587).

Etiology and Clinical Characteristics of Community-Acquired Pneumonia with Airway Malacia in Children

OBJECTIVE

The objective of this article is to study the etiology of community-acquired pneumonia in children with airway malacia.

METHODS

We retrospectively reviewed the medical records of 428 pneumonia patients. All patients underwent bronchoscopy, and bronchoalveolar lavage samples were processed for microbiological assessment.

RESULTS

In a total of 428 cases reviewed, 60 were found to have airway malacia. Pathogens were identified in 44 of the 60 specimens (73.3%), with 32 being single-pathogen infections. The most common pathogen was respiratory syncytial virus (RSV; 20%). Mixed-pathogen infections were observed in 12 patients. Airway malacia patients were younger than those without malacia (10.5 vs. 50 months, respectively; p < 0.001). Compared with those without airway malacia, wheezing, cyanosis and admission to the pediatric intensive care unit were more common in children with airway malacia and their hospital stay was longer.

CONCLUSION

RSV was the most common pathogen in those with airway malacia. Airway malacia was found to aggravate infectious pneumonia.

Contribution of Co-detected Respiratory Viruses and Patient Age to the Clinical Manifestations of Mycoplasma Pneumoniae Pneumonia in Children

BACKGROUND

The clinical spectrum of Mycoplasma pneumoniae pneumonia is widely variable. This study evaluated the clinical manifestations of M. pneumoniae pneumonia in children of different age groups and by the presence of co-detected respiratory virus.

METHODS

This study included children hospitalized with M. pneumoniae pneumonia between 2010 and 2015. At the time of pneumonia diagnosis, a nasopharyngeal aspirate was analyzed for respiratory viruses by reverse transcription-polymerase chain reaction (RT-PCR). The clinical manifestations and laboratory findings were reviewed from medical records.

RESULTS

Of the 286 children with M. pneumoniae pneumonia, 84 (29.4%) had a co-detected respiratory virus, with the highest co-detection rate in young children (51.9% of children <2 years; P = 0.002). In children <2 years, with and without co-detected virus, wheezing occurred in 35.7% and 15.4%, respectively. Among the 202 children without any virus detected, only 6.4% were <2 years. These young children showed fewer median days of fever than the children ≥2 years (8 vs. 11 days; P = 0.022). Children ≥2 years tended to have accompanying skin rashes (21.7% vs.7.7%; P = 0.310) and elevated liver enzymes (21.7% vs. 0%; P = 0.075) more frequently than children <2 years. Only 53.8% of the patients <2 years were treated with macrolide compared with 94.1% of the patients ≥2 years (P < 0.001).

CONCLUSIONS

The clinical manifestations of M. pneumoniae pneumonia in young children are milder than those in older children. A high prevalence of co-detected respiratory virus in young children suggests that virus might play a role in making pneumonia clinically apparent in this age group.

Clinical Characteristics of Macrolide-Resistant Mycoplasma pneumoniae from Children in Jeju

Mycoplasma pneumoniae is the major pathogen of community-acquired pneumonia in children. The prevalence of macrolide-resistant M. pneumoniae (MRMP) is important owing to the limited alternative therapies for children. We analyzed 111 M. pneumoniae obtained from 107 children admitted for lower respiratory tract infection at Jeju National University Hospital between 2010 and 2015. Macrolide resistance of M. pneumoniae was searched for using polymerase chain reaction (PCR) and sequencing. Of 107 clinical M. pneumoniae, 11 (10.3%) carried macrolide resistance mutations in the 23S rRNA gene. All macrolide resistance mutations were A2063G transitions. We found an acquired A2063G mutation of M. pneumoniae from a patient during macrolide treatment. Patients' characteristics and clinical severity did not differ between those with MRMP and macrolide-sensitive M. pneumoniae, with the exception of frequent pleural effusion in the MRMP group. The prevalence of MRMP (10.3%) in Jeju Island was relatively lower than those of surrounding countries in East Asia. Previous antimicrobial usage and timing of diagnostic test should be considered when determining of macrolide resistance of M. pneumoniae.

Radiologic findings as a determinant and no effect of macrolide resistance on clinical course of Mycoplasma pneumoniae pneumonia

Background

With the emergence of macrolide resistance, concerns about the efficacy of macrolides for the treatment of Mycoplasma pneumoniae (MP) pneumonia in children have been raised. This study aimed to determine the effect of macrolide resistance on the outcome of children who were hospitalized with MP pneumonia.

Methods

Between 2010 and 2015, we performed culture of MP from nasopharyngeal samples obtained from children who were hospitalized with pneumonia at five hospitals in Korea. Macrolide resistance was determined by the analysis of 23S rRNA gene transition and the minimal inhibitory concentrations of four macrolides. Medical records were reviewed to analyze the clinical response to treatment with macrolides.

Results

MP was detected in 116 (4.8%) of the 2436 children with pneumonia. MP pneumonia was prevalent in 2011 and 2015. Of the 116 patients with MP pneumonia, 82 (70.7%) were macrolide-resistant. There were no differences in the age distribution, total duration of fever, and chest x-ray patterns between the macrolide-susceptible and macrolide-resistant groups. After macrolide initiation, mean days to defervescence were longer in the macrolide-resistant group than in macrolide-susceptible group (5.7 days vs. 4.1 days, P = 0.021). However, logistic regression analysis revealed that the presence of extrapulmonary signs (P = 0.039), homogeneous lobar consolidation (P = 0.004), or parapneumonic effusion (P < 0.001) were associated with fever duration of ≥7 days after the initiation of macrolides, regardless of macrolide resistance.

Conclusions

This study demonstrated that fever duration in MP pneumonia was determined by the radiologic findings of chest x-ray, not by the presence of macrolide resistance. The results highlight the need for future studies to assess therapeutic benefit from macrolides in the treatment of children with MP pneumonia.

Prevalence and clinical manifestations of macrolide resistant Mycoplasma pneumoniae pneumonia in Korean children

Purpose

Macrolide resistance rate of Mycoplasma pneumoniae has rapidly increased in children. Studies on the clinical features between macrolide susceptible-M. pneumoniae (MSMP) and macrolide resistant-M. pneumoniae (MRMP) are lacking. The aim of this study was to identify the macrolide resistance rate of M. pneumoniae in Korean children with M. pneumoniae penupmonia in 2015 and compare manifestations between MSMP and MRMP.

Methods

Among 122 children (0–18 years old) diagnosed with M. pneumoniae pneumonia, 95 children with the results of macrolide sensitivity test were included in this study. Clinical manifestations were acquired using retrospective medical records.

Results

The macrolide resistant rate of M. pneumoniae was 87.2% (82 of 94 patients) in children with M. pneumoniae pneumonia. One patient showed a mixed type of wild type and A2063G mutation in 23S rRNA of M. pneumoniae. There were no significant differences in clinical, laboratory, and radiologic findings between the MSMP and MRMP groups at the first visit to our hospital. The time interval between initiation of macrolide and defervescence was significantly longer in the MRMP group (4.9±3.3 vs. 2.8±3.1 days, P=0.039).

Conclusion

The macrolide resistant rate of M. pneumoniae is very high in children with M. pneumoniae pneumonia in Korea. The clinical manifestations of MRMP are similar to MSMP except for the defervescence period after administration of macrolide. Continuous monitoring of the occurrence and antimicrobial susceptibility of MRMP is required to control its spread and establish strategies for treating second-line antibiotic resistant M. pneumoniae infection.

Epidemiology of Mycoplasma pneumoniae Infections in Japan and Therapeutic Strategies for Macrolide-Resistant M. pneumoniae

Pneumonia caused by Mycoplasma pneumoniae (M. pneumoniae pneumonia) is a major cause of community-acquired pneumonia worldwide. The surveillance of M. pneumoniae pneumonia is important for etiological and epidemiological studies of acute respiratory infections. In Japan, nation-wide surveillance of M. pneumoniae pneumonia has been conducted as a part of the National Epidemiological Surveillance of Infectious Diseases (NESID) program. This surveillance started in 1981, and significant increases in the numbers of M. pneumoniae pneumonia patients were noted in 1984, 1988, 2006, 2010, 2011, 2012, and 2015. The epidemics in 2011 and 2012 were particularly widespread and motivated researchers to conduct detailed epidemiological studies, including genotyping and drug resistance analyses of M. pneumoniae isolates. The genotyping studies based on the p1 gene sequence suggested that the p1 gene type 1 lineage has been dominant in Japan since 2003, including the epidemic period during 2011-2012. However, more detailed p1 typing analysis is required to determine whether the type 2 lineages become more relevant after the dominance of the type 1 lineage. There has been extensive research interest in implications of the p1 gene types on the epidemiology of M. pneumoniae infections. Serological characterizations of sera from patients have provided a glimpse into these associations, showing the presence of type specific antibody in the patient sera. Another important epidemiological issue of M. pneumoniae pneumonia is the emergence of macrolide-resistant M. pneumoniae (MRMP). MRMPs were noted among clinical isolates in Japan after 2000. At present, the isolation rate of MRMPs from pediatric patients is estimated at 50-90% in Japan, depending on the specific location. In view of the situation, Japanese societies have issued guiding principles for treating M. pneumoniae pneumonia. In these guiding principles, macrolides are still recommended as the first-line drug, however, if the fever does not subside in 48-72 h from first-line drug administration, a change of antibiotics to second-line drugs is recommended.

Development of a bead-based suspension array for the detection of pathogens in acute respiratory tract infections

We developed a high-throughput bead-based suspension array for simultaneous detection of 20 respiratory tract pathogens in clinical specimens. Pathogen-specific genes were amplified and hybridized to probes coupled to carboxyl-encoded microspheres. Fluorescence intensities generated via the binding of phycoerythrin-conjugated streptavidin with biotin-labeled targets were measured by the Luminex 100 bead-based suspension array system. The bead-based suspension array detected bacteria in a significantly higher number of samples compared to the conventional culture. There was no significant difference in the detection rate of atypical pathogensatypical pathogens or viruses between the bead-based suspension array and real-time PCR. This technology can play a significant role in screening patients with pneumonia.

Prevalence, genotyping and macrolide resistance of Mycoplasma pneumoniae among isolates of patients with respiratory tract infections, Central Slovenia, 2006 to 2014

In this retrospective study we employed real-time polymerase chain reaction (PCR) to analyse the occurrence of Mycoplasma pneumoniae among upper and lower respiratory tract infections (RTI) in the Central Region of Slovenia between January 2006 and December 2014. We also used a culture and pyrosequencing approach to genotype strains and infer their potential macrolide resistance. Of a total 9,431 tested samples from in- and out-patient with RTI, 1,255 (13%) were found to be positive by M. pneumoniae PCR. The proportion of positive samples was 19% (947/5,092)among children (≤16 years-old) and 7% (308/4,339) among adults (>16 years-old). Overall, among those PCR tested, the highest proportions of M. pneumonia infections during the study period were observed in 2010 and 2014. In these two years, 18% (218/1,237) and 25% (721/2,844) of samples were positive respectively,indicating epidemic periods. From the 1,255 M. pneumoniae PCR-positive samples, 783 (614 from paediatric and 169 from adult patients) were successfully cultured. Of these, 40% (312/783) were constituted of strains belonging to the P1 type II genomic group, while 60% (469/783) contained strains of the P1 type I group. Two isolates comprised both P1 type Iand II strains. Results of a genotype analysis by year,showed that the dominant M. pneumoniae P1 type during the 2010 epidemic was P1 type II (82% of isolates;81/99), which was replaced by P1 type I in the 2014 epidemic (75%; 384/510). This observation could indicate that the two epidemics may have been driven by a type shift phenomenon, although both types remained present in the studied population during the assessed period of time. Only 1% of strains (7/783) were found to harbour an A2063G mutation in the 23S rRNA gene,which confers macrolide resistance, suggesting that the occurrence of M. pneumoniae macrolide resistance still seems to be sporadic in our geographic area.

A nationwide study of children and adolescents with pneumonia who visited Emergency Department in South Korea in 2012

Purpose

Acute respiratory infection, particularly pneumonia, is the most common cause of hospitalization and death among children in developing nations. This study aimed to investigate the characteristics of children and adolescents with pneumonia who visited Emergency Department (ED) in South Korea in 2012.

Methods

We analyzed National Emergency Department Information System (NEDIS) records from 146 EDs in South Korea for all pediatric patients aged ≤18 years who were diagnosed with pneumonia between January and December 2012.

Results

Among 38,415 subjects, the male-to-female ratio was 1:0.8. Patients aged <12 months comprised 18.0% of the study population; those aged 1 to 3 years, 54.4%; those aged 4 to 6 years, 16.8%; those aged 7 to 12 years, 7.4%; and those aged 13 to 18 years, 3.4%. Presentation rates were highest in April, followed by January, March, and May. The hospital admission rate was 43.5%, of which 2.6% were in intensive care units. The mortality rate was 0.02%. Based on the International Classification of Diseases, 10th Revision, diagnostic codes, the types of pneumonia according to cause were viral pneumonia (29.0%), bacterial pneumonia (5.3%), Mycoplasmal pneumonia (4.5%), aspiration pneumonia (1.3%), and pneumonia of unknown origin (59.3%).

Conclusion

Despite the limited data due to the ED data from the NEDIS lacking laboratory results and treatment information, this study reflects well the outbreak patterns among children and adolescents with pneumonia. Our results provide a basis for future studies regarding ED treatment for children and adolescents with pneumonia.

Hepatitis associated with Mycoplasma pneumoniae infection in Korean children: a prospective study

Purpose

Mycoplasma pneumoniae (MP) infection is a major cause of respiratory infection in school-aged children. Extrapulmonary manifestations of MP infection are common, but liver involvement has been rarely reported. The aim of this study was to determine the clinical characteristics of MP-associated hepatitis.

Methods

This prospective study included 1,044 pediatric patients with MP infection diagnosed serologically with MP IgM at one medical center from January 2006 to December 2012. Eighty of these patients had elevated levels of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT), each greater than 50 IU/L, without any other specific liver disorder and were compared with the 964 children without liver disorders.

Results

In total, 7.7% of patients with MP infection had a diagnosis of hepatitis, especially in fall and winter. The ratio of male to female patients was 1.7:1, and the mean age of the patients was 5 years and 5 months. The most common symptoms were cough, fever, and sputum. Anorexia was the most common gastrointestinal symptom, followed by nausea/vomiting, diarrhea, and abdominal pain. Mean levels of AST and ALT were 100.65 IU/L and 118.73 IU/L, respectively. Serum AST/ALT level was normalized within 7.5 days on average without complications. The mean duration of hospitalization (11.3 days) was longer for children with hepatitis than for those without hepatitis (P=0.034).

Conclusion

MP-associated hepatitis is not uncommon and has a relatively good prognosis. Therefore, clinicians should be concerned about liver involvement in MP infection but avoid further unnecessary evaluation of hepatitis associated with MP.

Epidemiological comparison of three Mycoplasma pneumoniae pneumonia epidemics in a single hospital over 10 years

Purpose

Mycoplasma pneumoniae (MP) pneumonia epidemics have occurred in 3- to 4-year cycles in Korea. We evaluated the epidemiologic characteristics of MP pneumonia in Daejeon, Korea, from 2003 to 2012.

Methods

We retrospectively analyzed 779 medical records of children (0-15 years of old) with MP pneumonia admitted to our institution and compared the data from 3 recent epidemics.

Results

In 779 patients, the mean age and male-to-female ratio were 5.0±2.2 years and 1:1, and most cases were observed in autumn. There were three epidemics during the study period, in 2003, 2006-2007, and 2011. In our comparison of the three epidemics, we found no differences in mean age, the male-to-female ratio, hospital stay, or the rate of seroconverters during hospitalization. All three epidemics began in early summer and peaked in September 2003 and 2011 and in October 2006 and then gradually decreased until the next year's spring season, although the 2006 epidemic extended further into 2007. The peak age groups in the children in 2003 and 2006 were 3-6 year-olds (57.5% and 56%, respectively), but in the 2011 epidemic, the peak group was 1-4 year-olds (46.5%). The proportion of the <2 years of age group was 20%, 15.7% and 28.8%, and >10 years of age group was 5.2%, 13.8%, and 14.8% of total patients, respectively.

Conclusion

MP pneumonia outbreaks occurred every 3-4 years. The pattern of 3 recent epidemics was similar in demographic characteristics and seasonality with some variations in each outbreak.

Early Additional Immune-Modulators for Mycoplasma pneumoniae Pneumonia in Children: An Observation Study

Background

Mycoplasma pneumoniae (MP) pneumonia is a self-limiting disease, but some patients complain of progressive pneumonia, despite of appropriate antibiotic treatment. We aimed to introduce the role of immune-modulators (corticosteroid and/or intravenous immunoglobulin, IVIG) treatment for childhood MP pneumonia based on previous our experiences.

Materials and Methods

A retrospective case series analysis for 183 children with MP pneumonia was performed. MP pneumonia patients were diagnosed by two Immunoglobulin M (IgM) tests: the micro-particle agglutination method (≥1:40) and the cold agglutination test (≥1:4), and were examined twice at the initial admission and at discharge. Among 183 MP pneumonia patients, 90 patients with persistent fever for over 48 hours after admission or those with severe respiratory symptoms and signs received additional prednisolone (82 patients, 1 mg/kg/day) or intravenous methylprednisolone (8 patients, 5-10 mg/kg/day) with antibiotics. Four patients with aggravated clinical symptoms and chest radiographic findings after corticosteroid treatment received IVIG (1 g/kg/day, 1-2 doses).

Results

Mean age of 183 patients was 5.5 ± 3.2 years (6 months-15 years), and the male: female ratio was 1.1:1 (96:87). Fifty-seven patients (31%) were seroconverters and 126 seropositive patients showed increased diagnostic IgM antibody titres during admission (over 4 folds). The majority of the patients who received corticosteroids (86/90 cases) showed rapid defervescence within 48 hours with improved clinical symptoms, regardless of the used antibiotics. Also, 4 patients who received additional IVIG improved both clinically and radiographically within 2 days without adverse reaction.

Conclusions

In the era of macrolide-resistant MP strains, early additional immune-modulator therapy with antibiotics might prevent from the disease progression and reduce the disease morbidity without adverse reaction.

Multicenter case-control study protocol of pneumonia etiology in children: Global Approach to Biological Research, Infectious diseases and Epidemics in Low-income countries (GABRIEL network)

BACKGROUND

Data on the etiologies of pneumonia among children are inadequate, especially in developing countries. The principal objective is to undertake a multicenter incident case-control study of <5-year-old children hospitalized with pneumonia in developing and emerging countries, aiming to identify the causative agents involved in pneumonia while assessing individual and microbial factors associated with the risk of severe pneumonia.

METHODS/DESIGN

A multicenter case-control study, based on the GABRIEL network, is ongoing. Ten study sites are located in 9 countries over 3 continents: Brazil, Cambodia, China, Haiti, India, Madagascar, Mali, Mongolia, and Paraguay. At least 1,000 incident cases and 1,000 controls will be enrolled and matched for age and date. Cases are hospitalized children <5 years with radiologically confirmed pneumonia, and the controls are children without any features suggestive of pneumonia. Respiratory specimens are collected from all enrolled subjects to identify 19 viruses and 5 bacteria. Whole blood from pneumonia cases is being tested for 3 major bacteria. S. pneumoniae-positive specimens are serotyped. Urine samples from cases only are tested for detection of antimicrobial activity. The association between procalcitonin, C-reactive protein and pathogens is being evaluated. A discovery platform will enable pathogen identification in undiagnosed samples.

DISCUSSION

This multicenter study will provide descriptive results for better understanding of pathogens responsible for pneumonia among children in developing countries. The identification of determinants related to microorganisms associated with pneumonia and its severity should facilitate treatment and prevention.

Increased risk of refractory Mycoplasma pneumoniae pneumonia in children with atopic sensitization and asthma

Purpose

A nationwide outbreak of Mycoplasma pneumoniae pneumonia (MP) refractory to macrolide antibiotics occurred in Korea during 2011. Steroid therapy has been reported to be both efficacious and well tolerated in pediatric patients with refractory MP. We compared clinical features and laboratory characteristics between children with refractory MP requiring steroid treatment and those with macrolide-responsive MP and evaluated the risk factors associated with refractory MP.

Methods

We investigated 203 children who were admitted to our institution with MP from June to November 2011. Refractory MP was defined by persistent fever over 38.3℃ with progressive pulmonary consolidation or pleural effusion despite administration of appropriate macrolide antibiotics for 5 days or longer after admission. Steroid therapy was initiated on the fifth day after admission for refractory cases.

Results

There were 26 patients with refractory MP requiring steroid therapy. The mean duration of steroid therapy was 5.4 days and most of the patients were afebrile within 24 hours after initiation of steroid therapy. The prevalence of refractory MP was higher in patients with pleural effusion, lobar pneumonia affecting more than 2 lobes, higher levels of serum lactate dehydrogenase, increased oxygen requirements, and longer duration of hospitalization. Atopic sensitization and history of asthma were also associated with refractory MP after adjusting for age and gender.

Conclusion

Children with refractory MP had more severe pneumonia. Atopic sensitization and history of asthma may be risk factors for refractory MP requiring steroid therapy in Korean children.

Macrolide resistance of Mycoplasma pneumoniae, South Korea, 2000-2011

In Korea, Mycoplasma pneumoniae was detected in 255/2,089 respiratory specimens collected during 2000–2011; 80 isolates carried 23S rRNA gene mutations, and 69/123 culture-positive samples with the mutation were resistant to 5 macrolides. During 2000–2011, prevalence of the mutation increased substantially. These findings have critical implications for the treatment of children with mycoplasma pneumonia.

A cross-sectional study of the clinical characteristics of hospitalized children with community-acquired pneumonia in eight eastern cities in China

BACKGROUND

Community-acquired pneumonia in children is common in China. To understand current clinical characteristics and practice, we conducted a cross-sectional study to analyze quality of care on childhood pneumonia in eight eastern cities in China.

METHODS

Consecutive hospital records between January 1, 2010 and December 31, 2010 were collected from 13 traditional Chinese medicine (TCM) and western medicine (WM) hospitals in February, May, August, and November (25 cases per season, 100 cases over the year), respectively. A predesigned case report form was used to extract data from the hospital medical records.

RESULTS

A total of 1298 cases were collected and analyzed. Symptoms and signs upon admission at TCM and WM hospitals were cough (99.3% vs. 98.6%), rales (84.8% vs. 75.0%), phlegm (83.3% vs. 49.1%), and fever (74.9% vs. 84.0%) in frequency. Patients admitted to WM hospitals had symptoms and signs for a longer period prior to admission than patients admitted to TCM hospitals. Testing to identify etiologic agents was performed in 1140 cases (88.4%). Intravenous antibiotics were administered in 99.3% (595/598) of cases in TCM hospitals and in 98.6% (699/700) of cases in WM hospitals. Besides, Chinese herbal extract injection was used more frequently in TCM hospitals (491 cases, 82.1%) than in WM hospitals (212 cases, 30.3%) (p < 0.01). At discharge, 818 cases (63.0%) were clinically cured, with a significant difference between the cure rates in TCM (87.6%) and WM hospitals (42.0%) (OR = 9.8, 95% confidence interval (CI): 7.3 ~ 12.9, p < 0.01). Pathogen and previous medical history were more likely associated with the disappearance of rales (OR = 7.2, 95% CI: 4.8 ~ 10.9). Adverse effects were not reported from the medical records.

CONCLUSIONS

Intravenous use of antibiotics is highly prevalent in children with community-acquired pneumonia regardless of aetiology. There was difference between TCM and WM hospitals with regard to symptom profile and the use of antibiotics. Intravenous use of herbal injection was higher in TCM hospitals than in WM hospitals. Most of the cases were diagnosed based on clinical signs and symptoms without sufficient confirmation of aetiology. Audit of current practice is urgently needed to improve care.

Community-Acquired Pneumonia in the Conjugate Vaccine Era

Community-acquired pneumonia (CAP) remains one of the most common serious infections encountered among children worldwide. In this review, we highlight important literature and recent scientific discoveries that have contributed to our current understanding of pediatric CAP. We review the current epidemiology of childhood CAP in the developed world, appraise the state of diagnostic testing for etiology and prognosis, and discuss disease management and areas for future research in the context of recent national guidelines.

A literature review and survey of childhood pneumonia etiology studies: 2000-2010

The Pneumonia Etiology Research for Child Health (PERCH) project is the largest multicountry etiology study of childhood pneumonia since the Board on Science and Technology in International Development studies of the 1980s. However, it is not the only recent or ongoing pneumonia etiology study, and even with seven sites, it cannot capture all epidemiologic settings in the developing world. Funding providers, researchers and policymakers rely on the best available evidence to strategically plan programs, new research directions and interventions. We aimed to describe the current landscape of recent pneumonia etiology studies in children under 5 years of age in the developed and developing world, as ascertained by a literature review of relevant studies with data since the year 2000 and a survey of researchers in the field of childhood pneumonia. We collected information on the study population, study design, case definitions, laboratory samples and methods and identified pathogens. A literature review identified 88 studies with child pneumonia etiology results. As of June 2010, our survey of researchers identified an additional 65 ongoing and recently completed child pneumonia etiology studies. This demonstrates the broad existing context into which the PERCH study must be placed. However, the landscape analysis also reveals a multiplicity of case definitions, levels of clinician involvement, facility types, specimen collection, and laboratory techniques. It reinforces the need for the standardization of methods and analyses for present and future pneumonia etiology studies in order to optimize their cumulative potential to accurately describe the microbial causes of childhood pneumonia.

Evidence of acute Mycoplasma infection in a patient with incomplete and atypical kawasaki disease: a case report

The etiology of Kawasaki disease remains unknown despite extensive studies. Some researchers suggest that it is caused by an infectious agent. This is a case report where a patient with incomplete Kawasaki disease was found to have evidence compatible with acute Mycoplasma pneumoniae infection. This is one of the several case reports linking Mycoplasma pneumoniae to Kawasaki disease as a possible trigger. This is perhaps due to a superantigen or is mediated by some other mechanism. Accurate and timely testing for Mycoplasma infections is difficult and has its limitations. Despite this, Mycoplasma pneumoniae should be considered in the differential and workup for Kawasaki disease.

Fulminant and Fatal Multiple Organ Failure in a 12-Year-Old Boy With Mycoplasma pneumoniae Infection

Mycoplasma pneumoniae (Mp) is a unique pathogen that causes not only pulmonary but also extrapulmonary manifestations that must be rapidly diagnosed. A 12-year-old boy, with no relevant medical history, presented with fever, severe epigastric pain, and vomiting. Laboratory findings showed fulminant and cholestatic hepatitis, hemolytic anemia, thrombocytopenia, acute kidney injury, disseminated intravascular coagulopathy, acute myocardial infarction, and rhabdomyolysis. His clinical condition rapidly deteriorated during intubation and continuous renal replacement therapy. Despite intensive treatment, he did not recover. We report a case of fulminant and fatal multiple organ failure in a previously healthy boy with Mp infection, describing the possible pathomechanisms of multiple organ failure involved in the disease.

Diagnosis of pneumococcal empyema using immunochromatographic test on pleural fluid and serotype distribution in Korean children

To evaluate the diagnostic value of immunochromatographic test (ICT) on pleural fluid in diagnosing pneumococcal empyema in children and to determine pneumococcal serotypes, 62 exudative parapneumonic effusions from Korean children were tested with culture, ICT for S. pneumoniae, pneumococcal autolysin polymerase chain reaction (PCR), and subsequent sequencing. Of the 62 patients, culture was positive in 3 patients only (4.8%). Pneumococci were identified in 13 samples (21.0%) by sequencing-confirmed PCR and ICT, respectively. When pneumococcal empyema was defined by either positive culture or sequence confirmation, the sensitivity of ICT was 76.9% (10/13) and the specificity of ICT was 93.9%. Eight of 10 patients with positive ICT and culture-negative results had a history of prior antibiotics use, whereas none of the culture-proven cases had. Serotypes of PCR-positive samples were determined by multiplex PCR assays. Multiplex PCR detected serotypes 19A (6), 1 (1), 14 (1), 34 (1), and untypable (4). ICT on pleural fluid is a relatively sensitive and highly specific method for diagnosis of pneumococcal empyema, especially in children given prior antibiotics.

Role of Mycoplasma pneumoniae glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in mediating interactions with the human extracellular matrix

In different, phylogenetically unrelated micro-organisms, glycolytic enzymes play a dual role. In the cytosol they are involved in metabolic reactions whereas the surface-localized fraction of the enzymes contributes to adhesion and virulence. Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is a typical member of this group of multifunctional proteins. In this study, we characterized the GAPDH of Mycoplasma pneumoniae, a common pathogen of the human respiratory mucosa. Full-length GAPDH of M. pneumoniae was successfully expressed and used to produce a polyclonal antiserum. By immunofluorescence, colony blot and ELISA experiments with different fractions of the M. pneumoniae proteins, GAPDH was demonstrated to be present in the cytosol and at even higher concentrations at the surface of mycoplasmas. Nevertheless, antibodies against recombinant GAPDH were not detected in sera of immunized animals or of patients with confirmed M. pneumoniae infection. Recombinant GAPDH bound to different human cell lines in a concentration-dependent manner, and binding was inhibited by specific anti-GAPDH serum. In contrast, this antiserum did not significantly influence the adherence of M. pneumoniae to HeLa cells. When different human extracellular matrix proteins were tested in Western blot assays, GAPDH bound to fibrinogen. The results showed that the GAPDH of M. pneumoniae is a member of the family of cytosol-localized glycolytic enzymes, which also occur at the surface of the bacterium, and mediates interactions with the extracellular matrix proteins of the human host. Thus, the surface-exposed fraction of GAPDH may be a factor that contributes to the successful colonization of the human respiratory tract by M. pneumoniae.