The causative organisms of pediatric empyema in Korea

Community-acquired pneumonia in children: updated perspectives on its etiology, diagnosis, and treatment

Pneumonia is a common pediatric infectious disease that is familiar to pediatricians and a major cause of hospitalization worldwide. Recent well-designed epidemiologic studies in developed countries indicated that respiratory viruses are detected in 30%-70%, atypical bacteria in 7%-17%, and pyogenic bacteria in 2%-8% of children hospitalized with community-acquired pneumonia (CAP). The etiological distribution of CAP varies widely by child age and the epidemiological season of the respiratory pathogen. Moreover, diagnostic tests, particularly for the detection of Streptococcus pneumoniae and Mycoplasma pneumoniae, the 2 major bacterial pathogens involved in pediatric CAP, have several limitations. Therefore, management and empirical antimicrobial therapy for children with CAP should be applied in a stepwise manner based on recent epidemiological, etiological, and microbiological evidence.

The changes of prevalence and etiology of pediatric pneumonia from National Emergency Department Information System in Korea, between 2007 and 2014

Purpose

Understanding changes in pathogen and pneumonia prevalence among pediatric pneumonia patients is important for the prevention of infectious diseases.

Methods

We retrospectively analyzed data of children younger than 18 years diagnosed with pneumonia at 117 Emergency Departments in Korea between 2007 and 2014.

Results

Over the study period, 329,380 pediatric cases of pneumonia were identified. The most frequent age group was 1–3 years old (48.6%) and the next was less than 12 months of age (17.4%). Based on International Classification of Diseases, 10th revision diagnostic codes, confirmed cases of viral pneumonia comprised 8.4% of all cases, pneumonia due to Mycoplasma pneumoniae comprised 3.8% and confirmed cases of bacterial pneumonia 1.3%. The prevalence of confirmed bacterial pneumonia decreased from 3.07% in 2007 and 4.01% in 2008 to 0.65% in 2014. The yearly rate of pneumococcal pneumonia also decreased from 0.47% in 2007 to 0.08% in 2014. A periodic prevalence of M. pneumoniae pneumonia (MP) was identified.

Conclusion

The increased number of patients with pneumonia, bacterial pneumonia, pleural effusion, and empyema in 2011 and 2013–2014 resulted from an MP epidemic. We provide evidence that the frequency of confirmed cases of bacterial pneumonia and pneumococcal pneumonia has declined from 2007 to 2014, which can simultaneously reflect the effectiveness of the pneumococcal conjugate vaccine.

The changing epidemiology of childhood pneumococcal disease in Korea

The wide use of antimicrobial agents and 7-valent pneumococcal conjugate vaccine (PCV7) has led to major changes in the epidemiology of childhood pneumococcal diseases. In Korea, data on the population-based incidence of childhood invasive pneumococcal diseases (IPD) are not available; however, institution-based surveillance data suggest a substantial burden of childhood IPD. Following the introduction of the PCV7 in Korea in 2003, the proportion of IPD caused by vaccine-type pneumococci has decreased, while non-PCV7 serotypes, especially serotypes 19A and 6A, whose proportions had been increasing before the introduction of the vaccine, became predominant among childhood IPD isolates. This article reviews the overall impact of PCV7 utilization and summarizes the results obtained so far. Continuous monitoring and gathering of scientific evidence for the epidemiological transition of pneumococcal carriage and IPD will be important for the management of pneumococcal infections in Korea.

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.