Won Hee Seo

Predictive value of C-reactive protein in response to macrolides in children with macrolide-resistant Mycoplasma pneumoniae pneumonia

Purpose The prevalence of macrolide-resistant Mycoplasma pneumoniae (MRMP) has increased worldwide. The aim of this study was to estimate the proportion of MRMP in a tertiary hospital in Korea, and to find potential laboratory markers that could be used to predict the efficacy of macrolides in children with MRMP pneumonia. Methods A total of 95 patients with M. pneumoniae pneumonia were enrolled in this study. Detection of MRMP was based on the results of specific point mutations in domain V of the 23S rRNA gene. The medical records of these patients were reviewed retrospectively and the clinical course and laboratory data were compared. Results The proportion of patients with MRMP was 51.6% and all MRMP isolates had the A2063G point mutation. The MRMP group had longer hospital stay and febrile period after initiation of macrolides. The levels of serum C-reactive protein (CRP) and interleukin-18 in nasopharyngeal aspirate were significantly higher in patients who did not respond to macrolide treatment. CRP was the only significant factor in predicting the efficacy of macrolides in patients with MRMP pneumonia. The area under the curve for CRP was 0.69 in receiver operating characteristic curve analysis, indicating reasonable discriminative power, and the optimal cutoff value was 40.7 mg/L. Conclusion The proportion of patients with MRMP was high, suggesting that the prevalence of MRMP is rising rapidly in Korea. Serum CRP could be a useful marker for predicting the efficacy of macrolides and helping clinicians make better clinical decisions in children with MRMP pneumonia.

Mycoplasma pneumoniae associated stroke in a 3-year-old girl

Infectious diseases precede a significant proportion of acute ischemic strokes in children. Here, we report a case of acute ischemic stroke in a 3-year-old girl with a Mycoplasma pneumonia-associated respiratory tract infection. She developed an acquired prothrombotic state of protein S deficiency and had increased fibrinogen and fibrinogen degradation product levels and increased titer of antinuclear antibodies. However, these conditions were completely alleviated at the 1-month follow-up examination. Infection with M. pneumoniae may cause a transient prothrombotic state that can potentially cause a thrombus.

Outbreak of Late-onset Group B Streptococcal Infections in Healthy Newborn Infants after Discharge from a Maternity Hospital : A Case Report

During a four-week period, four healthy term newborn infants born at a regional maternity hospital in Korea developed late-onset neonatal group B Streptococcus (GBS) infections, after being discharged from the same nursery. More than 10 days after their discharge, all of the infants developed fever, lethargy, and poor feeding behavior, and were subsequently admitted to the Korea University Medical Center, Ansan Hospital. GBS was isolated from the blood cultures of three babies; furthermore, GBS was isolated from 2 cerebral spinal fluid cultures. Three babies had meningitis, and GBS was isolated from their cerebral spinal fluid cultures. This outbreak was believed to reflect delayed infection after early colonization, originating from nosocomial sources within the hospital environment. This report underlines the necessity for Korean obstetricians and pediatricians to be aware of the risk of nosocomial transmissions of GBS infection in the delivery room and/or the nursery.

Clinical manifestations of respiratory adenoviral infection among hospitalized children in Korea.

The objective of our study was to understand the epidemiological and clinical features of respiratory adenoviral infections among children at a single institution over the course of several years.

Attention deficit hyperactivity disorder in epileptic children

It is well-known that the prevalence of attention deficit hyperactivity disorder (ADHD) is higher in epileptic children than in the general pediatric population. The aim of this study was to compare the accompaniment of ADHD in epileptic children with well-controlled seizures and no significant intellectual disability with that in healthy controls. We included epileptic children between the ages of 6 and 12 yr visiting our clinic for six consecutive months and controls without significant medical or psychiatric illnesses. We excluded patients with intellectual disability or persistent seizures during the recent three months. The diagnosis of ADHD was based on the criteria of the Diagnostic and Statistical Manual of Mental Disorders-IV (DSM-IV). After exclusion of 84 patients, we enrolled 102 (54.8%) children (mean age, 9.4 ± 2.0 yr). Seven (7 of 102, 6.9%) were diagnosed with ADHD. As compared to control group (4 of 110, 3.6%), there was no difference in ADHD accompaniment (P = 0.29). No difference was observed in ADHD accompaniment according to seizure type and epilepsy syndrome. In conclusion, the accompaniment of ADHD in epileptic children with well-controlled seizures and no intellectual disability may not differ from that of the general pediatric population.

Changes in Major Peanut Allergens Under Different pH Conditions

Regional dietary habits and cooking methods affect the prevalence of specific food allergies; therefore, we determined the effects of various pH conditions on major peanut allergens. Peanut kernels were soaked overnight in commercial vinegar (pH 2.3) or acetic acid solutions at pH 1.0, 3.0, or 5.0. Protein extracts from the sera of seven patients with peanut-specific IgE levels >15 kUA/L were analyzed by SDS-PAGE and immunolabeling. A densitometer was used to quantify and compare the allergenicity of each protein. The density of Ara h 1 was reduced by treatment with pH 1.0, 3.0, or 5.0 acetic acid, or commercial vinegar. Ara h 2 remained largely unchanged after treatment with pH 5.0 acetic acid, and was decreased following treatment with pH 1.0, 2.3, or 3.0 acetic acid. Ara h 3 and Ara h 6 appeared as a thick band after treatment with pH 1.0 acetic acid and commercial vinegar. IgE-binding intensities to Ara h 1, Ara h 2, and Ara h 3 were significantly reduced after treatment with pH 1.0 acetic acid or commercial vinegar. These data suggest that treatment with acetic acid at various pH values affects peanut allergenicity and may explain the low prevalence of peanut allergy in Korea.

Macrolide Resistance and Its Impacts on M. Pneumoniae Pneumonia in Children: Comparison of Two Recent Epidemics in Korea

Purpose The aim of this study was to investigate the change in macrolide resistance rate in pediatric Mycoplasma pneumoniae pneumonia and to evaluate the influence of macrolide-resistant M. pneumoniae (MRMP) on the clinical course of disease, by comparing 2 recent, consecutive epidemics in Korea. Methods A total of 250 patients with M. pneumoniae pneumonia admitted to a single tertiary hospital were enrolled in this study. Detection of MRMP was based on specific point mutations in domain V of the 23S rRNA gene. The medical records of enrolled patients were reviewed retrospectively, and the clinical courses and laboratory data were compared. Results The macrolide resistance rate of M. pneumoniae was 51.1% (48/94) in the 2011 epidemic, and 87.2% (136/156) in the 2015 epidemic. All MRMP isolates had the A2063G point mutation. In comparison of 2 epidemics, the mean age of patients with M. pneumoniae pneumonia was increased, and the total febrile days and febrile days after initiation of macrolides were prolonged in the 2015 epidemic. Overall severity of MRMP or macrolide-susceptible M. pneumoniae (MSMP) pneumonia over 2 epidemics was not significantly changed. However, the proportion of patients who had a fever lasting more than 72 hours after initiation of macrolides and who received corticosteroid treatment were higher in MRMP pneumonia during 2 epidemics. Conclusions The macrolide resistance rate of M. pneumoniae has risen rapidly over 2 recent, consecutive epidemics, and this has been associated with a prolonged clinical course and increased use of corticosteroids to treat pediatric M. pneumoniae pneumonia.

What Characteristics Confer Proteins the Ability to Induce Allergic Responses? IgE Epitope Mapping and Comparison of the Structure of Soybean 2S Albumins and Ara h 2

Ara h 2, a peanut 2S albumin, is associated with severe allergic reactions, but a homologous protein, soybean 2S albumin, is not recognized as an important allergen. Structural difference between these proteins might explain this clinical discrepancy. Therefore, we mapped sequential epitopes and compared the structure of Ara h 2, Soy Al 1, and Soy Al 3 (Gly m 8) to confirm whether structural differences account for the discrepancy in clinical responses to these two proteins. Commercially synthesized peptides covering the full length of Ara h 2 and two soybean 2S albumins were analyzed by peptide microarray. Sera from 10 patients with peanut and soybean allergies and seven non-atopic controls were examined. The majority of epitopes in Ara h 2 identified by microarray are consistent with those identified previously. Several regions in the 2S albumins are weakly recognized by individual sera from different patients. A comparison of allergenic epitopes on peanut and soybean proteins suggests that loop-helix type secondary structures and some amino acids with a large side chain including lone electron pair, such as arginine, glutamine, and tyrosine, makes the peptides highly recognizable by the immune system. By utilizing the peptide microarray assay, we mapped IgE epitopes of Ara h 2 and two soybean 2S albumins. The use of peptide microarray mapping and analysis of the epitope characteristics may provide critical information to access the allergenicity of food proteins.

Apnea-related sleep fragmentation and poor vigilance in children with well-controlled asthma

It has been reported that sleep problems and neurocognitive deficit in asthmatic children is prevalent. However, systematic studies on these problems in stable asthma using polysomnography have rarely been performed. We therefore investigated sleep and neurocognitive functioning in children with well‐controlled asthma. Forty‐three children with well‐controlled, stable asthma and 31 controls (age range: 6–9 years) were enrolled in the study. Subjects were questioned for daytime sleepiness using the Paediatric Daytime Sleepiness Scale. Complete overnight polysomnography and neurocognitive function tests were performed on all subjects. Children with stable asthma had lower pulmonary function in comparison to their age‐matched controls. Asthmatic children had a higher apnea–hypopnea index (P < 0.001) and apnea–hypopnea‐related arousal index (P < 0.001) as compared with non‐asthmatics. Deep sleep was decreased in asthmatics (P = 0.001). In the vigilance test, the mean number of correct answers was lower (P = 0.005) and the mean reaction time was slower (P = 0.002) in asthmatic children. A hierarchical multiple linear regression showed that deep sleep and apnea–hypopnea‐related arousal index were significant predictors of vigilance. The data suggest that the prevalence of paediatric sleep‐disordered breathing and sleep fragmentation could be very high among children with well‐controlled asthma. Moreover, vigilance, the ability to maintain attention and alertness, was worse in stable asthmatic children when compared with healthy controls. Sleep‐disordered breathing should be checked even in stable asthmatic children as they are at risk for developing neurobehavioural deterioration associated with frequent arousals during sleep. Furthermore, early treatment for asthma may be required in order to prevent airway remodelling that could cause sleep problems.

Sleep duration is associated with body fat and muscle mass and waist-to-height ratio beyond conventional obesity parameters in Korean adolescent boys

While evidence has supported a strong association between sleep duration and obesity globally, results from studies of children and adolescents have been conflicting, and information about a sex‐specific association has been limited. This study aimed to investigate the association of sleep duration with various parameters of obesity among South Korean adolescents. This population‐based, cross‐sectional study analysed the data obtained from the Korea National Health and Nutrition Examination Surveys (KNHANES) 2009 and 2010. Data of 990 adolescents were analysed. Sleep duration was based on a self‐reported questionnaire. Body mass index (BMI), waist circumference (WC), waist‐to‐height ratio (WHtR), body fat percentage (BFP) and skeletal muscle index (SMI, appendicular skeletal muscle mass as a percentage of body weight) were assessed as parameters of obesity. Mean sleep duration in boys was associated inversely with BMI, WC, WHtR and BFP and positively with SMI. Proportions of the highest quartile of BMI, WC, WHtR and BFP and the lowest quartile of SMI increased significantly with increased sleep duration only in boys. Also, in boys, decreased sleep duration was associated significantly with the increased risk of the highest quartile of BMI, WC, WHtR and BFP and the lowest quartile of SMI, even after adjusting for confounding factors. However, in girls, there was no significant association between sleep duration and obesity parameters except WC. Periodic assessment of sleep duration in relation to body fat or muscle mass in male adolescents may be considered, especially in those who are at risk for obesity or related disorders.