Young Youn Choi

The Causative Organisms of Bacterial Meningitis in Korean Children in 1996-2005

Bacterial meningitis remains a serious cause of morbidity and mortality in childhood, despite the availability of effective vaccines against Haemophilus influenzae type b (Hib) or Streptococcus pneumoniae. The purpose of this study was to analyze data on bacterial meningitis cases in Korea from 1996 through 2005. The information of all hospitalized bacteria-proven meningitis cases was obtained from 17 university hospitals nationwide. A total of 402 cases were identified. Of these, 125 (29.9%) cases were neonates. Streptococcus agalactiae was the most common bacteria responsible for 99 (24.6%) of all cases regardless of age, followed by S. pneumoniae for 91 (22.6%) and H. influenzae for 67 (16.7%) patients. The common etiology beyond the neonatal period was S. pneumoniae for 91 (33.0%) followed by H. influenzae for 63 (22.8%) patients. The overall case fatality rate was 9.4%, which was similar with that in 1986-1995. In conclusion, S. agalactiae, S. pneumoniae and H. influenzae were important etiologic agents of bacterial meningitis in children in the last 10 yrs. It is required to establish the preventive strategy of the three bacteria. The nationwide epidemiologic study should be continued to evaluate immunization strategy and efficacy.

Necrotizing enterocolitis in newborns: update in pathophysiology and newly emerging therapeutic strategies

While the survival of extremely premature infants with respiratory distress syndrome has increased due to advanced respiratory care in recent years, necrotizing enterocolitis (NEC) remains the leading cause of neonatal mortality and morbidity. NEC is more prevalent in lower gestational age and lower birth weight groups. It is characterized by various degrees of mucosal or transmural necrosis of the intestine. Its exact pathogenesis remains unclear, but prematurity, enteral feeding, bacterial products, and intestinal ischemia have all been shown to cause activation of the inflammatory cascade, which is known as the final common pathway of intestinal injury. Awareness of the risk factors for NEC; practices to reduce the risk, including early trophic feeding with breast milk and following the established feeding guidelines; and administration of probiotics have been shown to reduce the incidence of NEC. Despite advancements in the knowledge and understanding of the pathophysiology of NEC, there is currently no universal prevention measure for this serious and often fatal disease. Therefore, new potential techniques to detect early biomarkers or factors specific to intestinal inflammation, as well as further strategies to prevent the activation of the inflammatory cascade, which is important for disease progression, should be investigated.

Comparison of Oral Ibuprofen and Intravenous Indomethacin for the Treatment of Patent Ductus Arteriosus in Extremely Low Birth Weight Infants

OBJECTIVE There are few published reports concerning the efficacy of oral ibuprofen for the treatment of patent ductus arteriosus (PDA) in extremely low birth weight (ELBW) infants. Oral ibuprofen was compared to intravenous indomethacin regarding efficacy and safety in the treatment of PDA in infants weighting less than 1,000g at birth. METHOD This was a retrospective study in a single center. Data on ELBW infants who had an echocardiographically confirmed PDA were collected. The infants were treated with either intravenous indomethacin or oral ibuprofen. Rate of ductal closure, need for additional treatment, drug-related side effects or complications, and mortality were compared between the two treatment groups. RESULT 26 infants who received indomethacin and 22 infants who received ibuprofen were studied. The overall rate of ductal closure was similar between the two treatments: it occurred in 23 of 26 infants (88.5%) treated with indomethacin, and in 18 of 22 infants (81.8%) treated with ibuprofen (p=0.40). The rate of surgical ligation (11.5% versus 18.2%; p=0.40) did not differ significantly between the two treatment groups. No significant difference was found in post-treatment serum creatinine concentrations between the two groups. There were no significant differences regarding additional side effects or complications. CONCLUSION In ELBW infants, oral ibuprofen is as efficacious as intravenous indomethacin for the treatment of PDA. There were no differences between the two drugs with respect to safety. Oral ibuprofen could be used as an alternative agent for the treatment of PDA in ELBW infants.

Immunogenicity, reactogenicity and safety of a human rotavirus vaccine (RIX4414) in Korean infants: a randomized, double-blind, placebo-controlled, phase IV study.

Rotavirus (RV) infection is the primary cause for childhood gastroenteritis worldwide. In Korea, RV infection is most common among children less than 5 y of age. This post-licensure study was conducted to further evaluate the RV vaccine (RIX4414) to provide additional local clinical data to the Korean Food and Drug Association. Healthy infants aged 6–12 weeks were enrolled to receive two doses of either RIX4414 or placebo as per 0, 1–2 mo schedule. Blood samples were collected before dose-1 and one month post-dose-2 of RIX4414/placebo to assess serum anti-RV IgA antibody concentrations using ELISA. Gastroenteritis stool samples were tested for the presence of RV using ELISA. RV positive samples were subjected to further analysis for G and P typing. Among 684 infants enrolled and vaccinated, 432 infants (RIX4414 = 318; placebo = 114) were included in the according-to-protocol cohort for immunogenicity. The anti-RV IgA antibody seroconversion rates in the RIX4414 group following one month post-dose-2 were 88.1% (95% CI: 84.0–91.4) and the corresponding geometric mean concentration in the RIX4414 group was 208.5 U/ml (95% CI: 174.2–249.5). Occurrence of solicited and unsolicited adverse events were similar in both, RIX4414 and placebo groups. None of the gastroenteritis stool samples tested positive for RV and no fatal SAEs were reported in either groups. The two-dose regimen of RIX4414 was observed to be immunogenic with a similar safety profile as compared with the placebo group, when administered to healthy Korean infants.

Multilocus sequence typing for the analysis of clonality among Candida albicans strains from a neonatal intensive care unit

Nosocomial Candida albicans infections are a significant problem in neonatal intensive care units (NICUs). We investigated the clonality of C. albicans isolates recovered over an 8-year period from neonates at a NICU. We also validated multilocus sequence typing (MLST) compared with pulsed-field gel electrophoresis (PFGE) for the genotyping of C. albicans strains from the same NICU. A total of 43 clinical isolates (10 blood, 19 urine, and 14 other) were obtained from 43 neonates between 2005 and 2012. Clonal strains were defined as the isolation of two or more strains with identical or similar genotypes as determined with both MLST and PFGE. Using MLST, the 43 isolates yielded 25 diploid sequence types (DSTs) and 10 DSTs were shared by 28 isolates (65.1%). Among the 28 isolates sharing 10 DSTs, isolates from each of seven DSTs had the same or similar PFGE pattern. In addition, two sets of isolates that differed by MLST at only one locus had the same or similar PFGE pattern. Overall, when the MLST and PFGE results were combined, 22 isolates (51.2%) shared eight genotypes, suggesting clonal strains. Strains from each of seven genotypes (total, 19 isolates) were isolated among the 22 clonal strains within a 6-month period, whereas three strains of one genotype were obtained over a 3-year interval. Our findings suggest that horizontal transmission of C. albicans may occur more frequently than vertical transmission among NICU patients and that MLST appears to be a useful method for genotyping C. albicans strains isolated from NICU patients.

Current status and clinical presentations of invasive neonatal Group B streptococcal infections in Korea

Background:  Group B streptococcus (GBS) is the most common cause of invasive neonatal infections in developed countries. The incidence of early‐onset GBS disease in Korea is known to be much lower than that in other developed countries; however neonatal GBS disease has been frequently reported in recent years in Korea. This retrospective study sought to determine the current status and clinical presentation of neonatal GBS disease in Korea.

Bloody nipple discharge in an infant

Although milky nipple discharge appears frequently in infants, bloody nipple discharge is a very rare finding. We experienced a 4-month-old, breast-fed infant who showed bilateral bloody nipple discharge with no signs of infection, engorgement, or hypertrophy. The infants hormonal examination and coagulation tests were normal, and an ultrasound examination revealed mammary duct ectasia. The symptoms resolved spontaneously within 6 weeks without any specific treatment, except that we advised the mother to refrain from taking herbal medicine. Since no such case has been previously reported in Korea, we present this case with a brief review of the literature.

Henoch-Schönlein purpura nephritis associated with Epstein-Barr virus infection in twins

We recently observed 6-year-old twin boys with HenochSch nlein purpura (HSP) nephritis associated with Epstein-Barr virus (EBV) infection. These twin boys were identical and healthy up to the age of 6 years. Twin 1 was admitted to our hospital because of abdominal pain, arthralgia in the left knee joint, and purpura on both lower extremities; 15 days before admission, he showed mild fever and cough; 3 days later, he developed intermittent abdominal pain and diffuse purpuric rash on his lower extremities. He was given acetaminophen for 3 days; 2 days before admission, he developed pain and swelling in the left knee joint. On admission, laboratory investigations revealed hemoglobin of 13.3 g/dl, white blood cell count of 15,600/mm3, platelet count of 296,000/mm3, erythrocyte sedimentation rate of 33 mm/h, blood urea nitrogen of 11.3 mg/dl, serum creatinine of 0.7 mg/dl, and serum albumin of 3.8 g/dl. Serum electrolytes, liver enzymes, blood coagulation tests, C3, C4, antinuclear antibody, rheumatoid factor, antistreptolysin O titer, and Mycoplasma antibody were normal. Urinalysis showed 3+ protein and 3+ blood, with many red blood cells (RBC) per high-power field (HPF). Urine protein excretion was 260 mg/m2 per day. EBV serology showed anti-EBV capsid antigen (VCA) IgM ( ), anti-EBV VCA IgG (+), anti-EBV early antigen (EA) IgG (+), and anti-EBV nuclear antigen (NA) IgG ( ). Other viral investigations for parvovirus B19, adenovirus, hepatitis B virus, and hepatitis A virus were negative. The patient was treated with intravenous hydration and 1 mg/kg per day oral prednisolone. The clinical findings of arthralgia, abdominal pain, and purpuric rash improved gradually over 10 days. He was discharged after 10 days with normal urinalysis. Physical examination and urinalysis were normal 6 months after discharge. Twin 2 was admitted on the same day as twin 1; 4 days before admission, he developed a mild cough. He was not receiving any medication; 1 day before admission, he had a painful left ankle joint and purpura on both lower extremities. On admission, he showed diffuse purpuric rash on the lower extremities and buttocks. He also had painful and swollen knees and ankles. Laboratory studies revealed hemoglobin of 11.7 g/dl, white blood cell count of 8,700/mm3, platelet count of 346,000/mm3, and normal microscopic urinalysis. EBV serology showed anti-EBV VCA IgM ( ), anti-EBV VCA IgG (+), anti-EBV EA IgG (+), and anti-EBV NA IgG ( ). Other laboratory studies and viral investigations were negative. He was treated with intravenous hydration and bed rest; 3 days after admission, he complained of severe abdominal pain and edema on the right ear auricle. He was treated with 1 mg/ kg per day oral prednisolone for 7 days. The clinical findings resolved gradually, so he was discharged with twin 1; 2 weeks after discharge, urinalysis revealed 2+ proteinuria and hematuria of 30–39 RBC/HPF. Other clinical findings were normal. He showed isolated microscopic hematuria for 1 month. Physical examination and urinalysis were normal 6 months after discharge. The cause of HSP is unknown, but HSP typically follows an upper respiratory tract infection. EBV has been reported to precede HSP [1]. The results of EBV serology in children are often different from adults or adolescents. In patients with negative heterophil antibody and antiEBV VCA IgM, tests for anti-EBV VCA IgG or anti-EBV C. J. Kim · Y. J. Woo · H. Kook · Y. Y. Choi · J. S. Ma · T. J. Hwang Department of Pediatrics, Chonnam National University Medical School, Gwangju, Korea

Transient complete atrioventricular block in a preterm neonate with congenital myotonic dystrophy: case report.

Congenital myotonic dystrophy (CMD) is an inherited neuromuscular disorder with cardiac rhythm abnormalities that may occur as a child grows. No report has described complete atrioventricular (AV) block detected in a neonate with CMD. We report a floppy infant of 31+4 weeks gestation with complete AV block at birth, who was diagnosed with CMD by Southern analysis. She recovered from complete AV block 32 hr after temporary transcutaneous pacing was applied. To the best our knowledge, this is the first recorded case of a complete AV block accompanied by CMD during the neonatal period. When a newborn has a complete AV block, the physician should consider the possibility of the CMD and conduct a careful physical examination. Graphical Abstract

Early Changes in the Serotype Distribution of Invasive Pneumococcal Isolates from Children after the Introduction of Extended-valent Pneumococcal Conjugate Vaccines in Korea, 2011-2013

This study was performed to measure early changes in the serotype distribution of pneumococci isolated from children with invasive disease during the 3-year period following the introduction of 10- and 13-valent pneumococcal conjugate vaccines (PCVs) in Korea. From January 2011 to December 2013 at 25 hospitals located throughout Korea, pneumococci were isolated among children who had invasive pneumococcal disease (IPD). Serotypes were determined using the Quellung reaction, and the change in serotype distribution was analyzed. Seventy-five cases of IPD were included. Eighty percent of patients were aged 3-59 months, and 32% had a comorbidity that increased the risk of pneumococcal infection. The most common serotypes were 19A (32.0%), 10A (8.0%), and 15C (6.7%). The PCV7 serotypes (4, 6B, 9V, 14, 18C, 19F, 23F, and 6A) accounted for 14.7% of the total isolates and the PCV13 minus PCV7 types (1, 3, 5, 7F and 19A) accounted for 32.0% of the total isolates. Serotype 19A was the only serotype in the PCV13 minus PCV7 group. The proportion of serotype 19A showed decreasing tendency from 37.5% in 2011 to 22.2% in 2013 (P = 0.309), while the proportion of non-PCV13 types showed increasing tendency from 45.8% in 2011 to 72.2% in 2013 (P = 0.108). Shortly after the introduction of extended-valent PCVs in Korea, serotype 19A continued to be the most common serotype causing IPD in children. Subsequently, the proportion of 19A decreased, and non-vaccine serotypes emerged as an important cause of IPD. The impact of extended-valent vaccines must be continuously monitored.