Proven Cytomegalovirus Colitis Associated with Dasatinib Administration in Two Pediatric Allogeneic Hematopoietic Stem Cell Transplantation Recipients / 대한소아소화기영양학회지

Gastrointestinal (GI) bleeding is a rare adverse event of dasatinib, which is known to be caused by dasatinib-induced colitis, severe thrombocytopenia, and platelet dysfunction.We present two cases of pediatric patients who developed hematochezia during treatment with dasatinib after hematopoietic stem cell transplantation (HSCT). A colonic tissue biopsy was performed to differentiate the cause of GI bleeding. Both patients were diagnosed with proven cytomegalovirus (CMV) colitis, but only one was treated with ganciclovir. The patient who did not receive antiviral therapy experienced recurrent GI bleeding during dasatinib administration, leading to multiple treatment interruptions. During dasatinib therapy after HSCT, patients with GI bleeding and confirmed CMV colitis may benefit from antiviral therapy to reduce interruptions in dasatinib therapy.

Twenty-Five Year Trend Change in the Etiology of Pediatric Invasive Bacterial Infections in Korea, 1996–2020

Background@#The coronavirus disease-2019 (COVID-19) pandemic has contributed to the change in the epidemiology of many infectious diseases. This study aimed to establish the pre-pandemic epidemiology of pediatric invasive bacterial infection (IBI). @*Methods@#A retrospective multicenter-based surveillance for pediatric IBIs has been maintained from 1996 to 2020 in Korea. IBIs caused by eight bacteria (Streptococcus pneumoniae, Haemophilus influenzae, Neisseria meningitidis, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus pyogenes, Listeria monocytogenes, and Salmonella species) in immunocompetent children > 3 months of age were collected at 29 centers. The annual trend in the proportion of IBIs by each pathogen was analyzed. @*Results@#A total of 2,195 episodes were identified during the 25-year period between 1996 and 2020. S. pneumoniae (42.4%), S. aureus (22.1%), and Salmonella species (21.0%) were common in children 3 to 59 months of age. In children ≥ 5 years of age, S. aureus (58.1%), followed by Salmonella species (14.8%) and S. pneumoniae (12.2%) were common. Excluding the year 2020, there was a trend toward a decrease in the relative proportions of S. pneumoniae (rs = −0.430, P = 0.036), H. influenzae (rs = −0.922, P 3 months of age. These findings can be used as the baseline data to navigate the trend in the epidemiology of pediatric IBI in the post COVID-19 era.

Clinical Manifestations, Epidemiologic Characteristics, and Disease Burden of the Coronavirus Disease-19 in Children Ages 5-11 Years Old

Coronavirus disease 2019 (COVID-19) has been a global pandemic for over 2 years. During the Omicron (B.1.1.529) variant-predominant period in South Korea, confirmed cases among children and adolescents surged. This review found that, although younger children may be less susceptible to COVID-19 than adolescents, more research is needed on the role of children and adolescents in the disease’s spread. Detailed epidemiological information about the transmissibility of the novel severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) strain in children and adolescents is currently scarce, and more research is needed on the role of children and adolescents in disease’s spread. There may be a difference in the proportion of cases with severe disease requiring hospitalization depending on the dominant mutant strain; however, COVID-19 generally presents with a mild-to-moderate course in children aged 5–11 years old.

Changes in the Incidence of Intussusception and Infectious Diseases After the COVID-19 Pandemic in Korea

Background@#Intussusception refers to the invagination of a part of the intestine into itself. The exact cause for this condition is unknown in most cases. The active implementation of coronavirus disease 2019 (COVID-19) infection control guidelines has reduced the spread of COVID-19 and the incidence of other infectious diseases in children. The current study aimed to identify changes in pediatric intussusception and infectious diseases after the implementation of infection control guidelines and confirm the association between intussusception and contagious diseases. @*Methods@#We analyzed the electronic medical records of pediatric patients diagnosed with intussusception from seven hospitals in Korea between January 2017 and December 2020.We used open data from the Korea Disease Control and Prevention Agency to investigate changes in infectious diseases over the same period. @*Results@#Altogether, we evaluated 390 children with intussusception. There was a statistically significant decrease in the incidence of monthly visits with intussusception in the COVID-19 period group (9.0 vs. 3.5, P < 0.001). When the monthly incidence of infectious diseases was compared between the pre-COVID-19 and the COVID-19 periods, a statistically significant decrease in respiratory viruses (7979.0 vs. 815.2, P < 0.001), enterovirus infection (262.2 vs. 6.6, P < 0.001), and viral enteritis (916.2 vs. 197.8, P< 0.001) were confirmed in the COVID-19 period. Through interrupted time series analysis, it was confirmed that the incidence of intussusception and viral infectious diseases have drastically decreased since March 2020, when COVID-19 infection control guidelines were actively implemented. @*Conclusion@#We confirmed that implementing infection control guidelines during the COVID-19 pandemic resulted in a decrease in intussusception and viral infectious diseases.Through this result, it was possible to indirectly confirm the existing hypothesis that viral infections play a significant role in the pathophysiologic mechanism of intussusception.

Updates on Coronavirus Disease-2019 Vaccine and Consideration in Children

As of March 2021, humanity has been suffering from the global severe acute respiratory syndrome coronavirus 2 pandemic that began late 2019. In 2020, new vaccine platforms— including mRNA vaccines and viral vector-based DNA vaccines—have been given emergency use authorization (EUA), leading to rolling out the vaccines for global mass vaccinations.The purpose of this article is to review the currently most widely used coronavirus disease 2019 vaccines: their action mechanisms and efficacy and safety data from clinical trials that have been published to date. In addition, the current status of clinical trials in the pediatric population was summarized, and further consideration for them was discussed.

Updates on Coronavirus Disease-2019 Vaccine and Consideration in Children

As of March 2021, humanity has been suffering from the global severe acute respiratory syndrome coronavirus 2 pandemic that began late 2019. In 2020, new vaccine platforms— including mRNA vaccines and viral vector-based DNA vaccines—have been given emergency use authorization (EUA), leading to rolling out the vaccines for global mass vaccinations.The purpose of this article is to review the currently most widely used coronavirus disease 2019 vaccines: their action mechanisms and efficacy and safety data from clinical trials that have been published to date. In addition, the current status of clinical trials in the pediatric population was summarized, and further consideration for them was discussed.

The Impact of the Coronavirus Disease-2019 Pandemic on Childhood Obesity and Vitamin D Status

Background@#The risk of weight gain as a consequence of school closure in children during the coronavirus disease-2019 (COVID-19) pandemic has been recognized. This study was performed to investigate changes in anthropometric and metabolic parameters in children following a 6-month period of social distancing and school closure due to the pandemic. @*Methods@#This retrospective cohort study was conducted in school-aged children that were on routine follow-up at the Growth Clinic of Seoul St. Mary's Hospital. Changes in body mass index (BMI) standard deviation scores (z-scores), lipid profiles, and vitamin D levels were investigated. The 1-year period prior to school closure was defined as “pre-COVID-19 period,” and the subsequent 6-month period as “COVID-19 period.” @*Results@#Overall, 226 children between 4 to 14 years old without comorbidities were assessed. On average, their BMI z-scores increased by 0.219 (95% confidence interval [CI], 0.167–0.271; P < 0.001) in the COVID-19 period compared to the pre-COVID-19 period, and the proportion of overweight or obesity increased from 23.9% in the pre-COVID-19 period to 31.4% in the COVID-19 period. The number of days after school closure ( P = 0.004) and being in the normoweight category in the pre-COVID-19 period ( P = 0.017) were factors associated with an increased BMI in the COVID-19 period. The mean triglyceride (105.8 mg/dL vs. 88.6 mg/dL, P < 0.001) and low-density lipoprotein-cholesterol (100.2 mg/dL vs. 94.0 mg/dL, P = 0.002) levels were higher, whereas the calcidiol level (18.9 mg/dL vs. 23.8 mg/dL, P < 0.001) was lower in the COVID-19 period compared to the pre-COVID-19 period. @*Conclusion@#Within 6 months, increased childhood obesity and vitamin D deficiencies were observed. The duration of school closure was significantly associated with an increased BMI and being normoweight does not exclude the risks for gaining weight.

Circulating Respiratory Syncytial Virus Genotypes and Genetic Variability of the G Gene during 2017 and 2018/2019 Seasonal Epidemics Isolated from Children with Lower Respiratory Tract Infections in Daejeon, Korea

Background@#Respiratory syncytial virus (RSV) is a major pathogen causing respiratory tract infections in infants and young children. The aim of this study was to confirm the genetic evolution of RSV causing respiratory infections in children at Daejeon in Korea, through G gene analysis of RSV-A and RSV-B strains that were prevalent from 2017 to 2019. @*Methods@#Pediatric patients admitted for lower respiratory tract infections at The Catholic University of Korea Daejeon St. Mary's Hospital in the 2017 and 2018/2019 RSV seasonal epidemics, who had RSV detected via multiplex polymerase chain reaction (PCR) were included. The nucleic acid containing RSV-RNA isolated from each of the patients' nasal discharge during standard multiplex PCR testing was stored. The G gene was sequenced and phylogenetic analysis was performed using MEGA X program and the genotype was confirmed. @*Results@#A total of 155 specimens including 49 specimens from 2017 and 106 specimens from 2018-2019 were tested. The genotype was confirmed in 18 specimens (RSV-A:RSV-B = 4:14) from 2017 and 8 specimens (RSV-A:RSV-B = 7:1) from 2018/2019. In the phylogenetic analysis, all RSV-A type showed ON1 genotype and RSV-B showed BA9 genotype. @*Conclusion@#RSV-B belonging to BA9 in 2017, and RSV-A belonging to ON1 genotype in 2018/2019 was the most prevalent circulating genotypes during the two RSV seasons in Daejeon, Korea.

Circulating Respiratory Syncytial Virus Genotypes and Genetic Variability of the G Gene during 2017 and 2018/2019 Seasonal Epidemics Isolated from Children with Lower Respiratory Tract Infections in Daejeon, Korea

Background@#Respiratory syncytial virus (RSV) is a major pathogen causing respiratory tract infections in infants and young children. The aim of this study was to confirm the genetic evolution of RSV causing respiratory infections in children at Daejeon in Korea, through G gene analysis of RSV-A and RSV-B strains that were prevalent from 2017 to 2019. @*Methods@#Pediatric patients admitted for lower respiratory tract infections at The Catholic University of Korea Daejeon St. Mary's Hospital in the 2017 and 2018/2019 RSV seasonal epidemics, who had RSV detected via multiplex polymerase chain reaction (PCR) were included. The nucleic acid containing RSV-RNA isolated from each of the patients' nasal discharge during standard multiplex PCR testing was stored. The G gene was sequenced and phylogenetic analysis was performed using MEGA X program and the genotype was confirmed. @*Results@#A total of 155 specimens including 49 specimens from 2017 and 106 specimens from 2018-2019 were tested. The genotype was confirmed in 18 specimens (RSV-A:RSV-B = 4:14) from 2017 and 8 specimens (RSV-A:RSV-B = 7:1) from 2018/2019. In the phylogenetic analysis, all RSV-A type showed ON1 genotype and RSV-B showed BA9 genotype. @*Conclusion@#RSV-B belonging to BA9 in 2017, and RSV-A belonging to ON1 genotype in 2018/2019 was the most prevalent circulating genotypes during the two RSV seasons in Daejeon, Korea.

Molecular Epidemiologic Study of a Methicillin-resistant Staphylococcus aureus Outbreak at a Newborn Nursery and Neonatal Intensive Care Unit

PURPOSE: This study aimed to investigate the molecular epidemiology of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak at a newborn nursery and neonatal intensive care unit (NICU).METHODS: During the outbreak, from August to September 2017, MRSA isolates collected from neonates and medical staff underwent genotyping and screened for virulence factors. Antibiotic susceptibilities were tested.RESULTS: During the study period, 41 neonates were admitted at the nursery (n=27) and NICU (n=14). Of these, 7 had MRSA infections (skin infection [n=6] and sepsis [n=1]) and 4 were colonized with MRSA. Associated medical staff (n=32) were screened; three were nasal MRSA carriers. Staphylococcal chromosomal cassette mec (SCCmec) type II, sequence type (ST) 89, spa type t375 was found to be the skin infection outbreak causing strain, with multi-drug resistance including low-level mupirocin resistance. SCCmec type IVa, ST 72, and a novel spa type designated t17879, was the cause of MRSA sepsis. Many different types of MRSA were colonized on the neonates; however, SCCmec type IVa, ST 72, spa type t664 was colonized in both neonates and a NICU nurse. All MRSA isolates from colonized infants were positive for the Panton-Valentine leukocidin (PVL) toxin gene.CONCLUSIONS: The strain causing an outbreak of skin infections had multi-drug resistance. Also, MRSA colonized in the neonates were found to carry the PVL toxin gene. Because different strains are present during an outbreak, molecular epidemiologic studies are important to identify the outbreak strain and colonized strains which aid in effective control and prevention of future MRSA outbreaks.

Novel reassortants of clade 2.3.4.4 H5N6 highly pathogenic avian influenza viruses possessing genetic heterogeneity in South Korea in late 2017

Novel H5N6 highly pathogenic avian influenza viruses (HPAIVs) were isolated from duck farms and migratory bird habitats in South Korea in November to December 2017. Genetic analysis demonstrated that at least two genotypes of H5N6 were generated through reassortment between clade 2.3.4.4 H5N8 HPAIVs and Eurasian low pathogenic avian influenza virus in migratory birds in late 2017, suggesting frequent reassortment of clade 2.3.4.4 H5 HPAIVs and highlighting the need for systematic surveillance in Eurasian breeding grounds.

Clinical implications in laboratory parameter values in acute Kawasaki disease for early diagnosis and proper treatment / 소아과

PURPOSE: This study aimed to analyse laboratory values according to fever duration, and evaluate the relationship across these values during the acute phase of Kawasaki disease (KD) to aid in the early diagnosis for early-presenting KD and incomplete KD patients. METHODS: Clinical and laboratory data of patients with KD (n=615) were evaluated according to duration of fever at presentation, and were compared between patients with and without coronary artery lesions (CALs). For evaluation of the relationships across laboratory indices, patients with a fever duration of 5 days or 6 days were used (n=204). RESULTS: The mean fever duration was 6.6±2.3 days, and the proportions of patients with CALs was 19.3% (n=114). C-reactive proteins (CRPs) and neutrophil differential values were highest and hemoglobin, albumin, and lymphocyte differential values were lowest in the 6-day group. Patients with CALs had longer total fever duration, higher CRP and neutrophil differential values and lower hemoglobin and albumin values compared to patients without CALs. CRP, albumin, neutrophil differential, and hemoglobin values at the peak inflammation stage of KD showed positive or negative correlations each other. CONCLUSION: The severity of systemic inflammation in KD was reflected in the laboratory values including CRP, neutrophil differential, albumin, and hemoglobin. Observing changes in these laboratory parameters by repeated examinations prior to the peak of inflammation in acute KD may aid in diagnosis of early-presenting KD patients.

Clinical implications of DMSA Scan in Childhood Acute Pyelonephritis

PURPOSE: This study aimed to evaluate the relationships between 99mTecnicium-dimercaptosuccinic acid (DMSA) scan findings and clinical parameters including age and fever duration. METHODS: The positive rates for abnormal DMSA scans were analyzed according to the age of patients, fever duration prior to admission, and total fever duration. DMSA scan findings were divided into 3 categories: single defect, multifocal defects, and discrepant defects. We evaluated the detection rates of vesicoureteral reflux according to DMSA scan lesions. RESULTS: Among a total 320 cases, 141 (44.1%) had abnormal DMSA scans. The infant group (0-1 year of age) had a shorter total fever duration, and a lower C-reactive protein (CRP) value and DMSA positive rate (39.8% vs. 60.6%, P=0.002) compared to children group (2-15 years of age). Patients with abnormal scans had a longer total fever duration and higher CRP compared to those with normal scans. The positivity rate of abnormal scans did not differ between the patients with a short fever duration prior to admission of ≤2 days and those with longer fever duration of ≥3 days. However, patients with longer total fever duration had a higher rate of abnormal DMSA scans (P=0.02). Among cases with a single defect, multifocal defects, and discrepant defects, vesicoureteral reflux was observed in 22.4%, 60% and 70.6% of cases, respectively (P=0.004). CONCLUSION: Although DMSA scan has limitations in early diagnosis, DMSA scan findings may aid in the prediction of the severity of systemic inflammation and detection of vesicoureteral reflux.

Clinical implications of DMSA Scan in Childhood Acute Pyelonephritis

PURPOSE: This study aimed to evaluate the relationships between 99mTecnicium-dimercaptosuccinic acid (DMSA) scan findings and clinical parameters including age and fever duration. METHODS: The positive rates for abnormal DMSA scans were analyzed according to the age of patients, fever duration prior to admission, and total fever duration. DMSA scan findings were divided into 3 categories: single defect, multifocal defects, and discrepant defects. We evaluated the detection rates of vesicoureteral reflux according to DMSA scan lesions. RESULTS: Among a total 320 cases, 141 (44.1%) had abnormal DMSA scans. The infant group (0-1 year of age) had a shorter total fever duration, and a lower C-reactive protein (CRP) value and DMSA positive rate (39.8% vs. 60.6%, P=0.002) compared to children group (2-15 years of age). Patients with abnormal scans had a longer total fever duration and higher CRP compared to those with normal scans. The positivity rate of abnormal scans did not differ between the patients with a short fever duration prior to admission of ≤2 days and those with longer fever duration of ≥3 days. However, patients with longer total fever duration had a higher rate of abnormal DMSA scans (P=0.02). Among cases with a single defect, multifocal defects, and discrepant defects, vesicoureteral reflux was observed in 22.4%, 60% and 70.6% of cases, respectively (P=0.004). CONCLUSION: Although DMSA scan has limitations in early diagnosis, DMSA scan findings may aid in the prediction of the severity of systemic inflammation and detection of vesicoureteral reflux.

Pathogenicity of H5N8 virus in chickens from Korea in 2014

In 2014, two genetically distinct H5N8 highly pathogenic avian influenza (HPAI) viruses were isolated from poultry and wild birds in Korea. The intravenous pathogenicity indices for the two representative viruses were both 3.0. Mortality of chickens intranasally inoculated with the two H5N8 viruses was 100% with a mean death times of 2.5 and 4.5 days. Mortality rates of the contact groups for the two H5N8 viruses were 33.3% and 66.6%. Our study showed that transmissibility of the novel H5N8 viruses was different from that of previously identified H5N1 HPAI viruses, possibly due to genetic changes.

Voriconazole Therapeutic Drug Monitoring is Necessary for Children with Invasive Fungal Infection / 소아감염

PURPOSE: To determine the clinical significance of voriconazole therapeutic drug monitoring (TDM) in the pediatric population. METHODS: Twenty-eight patients with invasive fungal infections administered with voriconazole from July 2010 to June 2012 were investigated retrospectively. Fourteen received TDM, and 143 trough concentrations were analyzed. All 28 patients were assessed for adverse events and treatment response six weeks into treatment, and at the end. RESULTS: Out of 143 samples, 53.1% were within therapeutic range (1.0-5.5 mg/L). Patients administered with the same loading (6 mg/kg/dose) and maintenance (4 mg/kg/dose) dosages prior to initial TDM showed highly variable drug levels. Adverse events occurred in 9 of 14 patients (64.3%) in both the TDM and non-TDM group. In the TDM group, voriconazole-related encephalopathy (n=2, 14.3%) and aspartate aminotransferase (AST) or alanine aminotransferase (ALT) elevation (n=8, 57.1%) occurred with serum levels in the toxic range (>5.5 mg/L), whereas blurred-vision (n=2, 14.3%) occurred within the therapeutic range (1.18 mg/L and 3.9 mg/L). The frequency of voriconazole discontinuation due to adverse events was lower in the TDM group (0.0% vs. 18.2%, P=0.481). Overall, 57.2% of the patients in the TDM group versus 14.3% in the non-TDM group showed clinical response after 6 weeks (P=0.055), whereas 21.4% in the TDM group versus 14.3% in the non-TDM group showed response at final outcome (P=0.664). In the TDM group, >67.0% of the serum levels were within therapeutic range for the first 6 weeks; however 45.5% were within therapeutic range for the entire duration. CONCLUSION: Routine TDM is recommended for optimizing the therapeutic effects of voriconazole.

Outcome of Antimicrobial Therapy of Pediatric Urinary Tract Infections Caused by Extended-Spectrum beta-Lactamase-Producing Enterobacteriaceae

BACKGROUND: The purpose of this study was to compare the outcome of carbapenem versus non-carbapenem antimicrobial therapy for pediatric urinary tract infections (UTIs) caused by extended-spectrum beta-lactamase (ESBL) producing Enterobacteriaceae. MATERIALS AND METHODS: From 2006 to 2011, 42 episodes of UTI caused by ESBL-producing Enterobacteriaceae were diagnosed at Seoul National University Children's Hospital. Patients were grouped according to the antimicrobials they received into a carbapenem group and a non-carbapenem group. Medical records were retrospectively reviewed to assess treatment outcome, time to defervescence after initiation of treatment, and relapse rate. RESULTS: There were 36 children with 42 episodes of UTI caused by ESBL-producing Enterobacteriaceae. Twenty-seven cases (64%) had an underlying urologic disease, 28 (67%) cases were caused by Escherichia coli, and 14 (33%) cases were caused by Klebsiella pneumoniae. Four (10%) cases were treated with carbapenem, 23 cases (55%) were treated with non-carbapenem, and 15 (36%) cases were treated by switching from a carbapenem to a non-carbapenem and vice versa. There was no treatment failure at the time of antimicrobial discontinuation. Between the carbapenem and the non-carbapenem treatment groups, there were no significant differences in bacterial etiology (P = 0.59), time to defervescence after the initiation of antimicrobials (P = 0.28), and relapse rate (P = 0.50). In vitro susceptibility to non-carbapenem antimicrobials did not affect the time to defervescence after the initiation of antimicrobial treatment, and the relapse rate in the non-carbapenem group. CONCLUSIONS: This study found no significant difference in the treatment outcome between pediatric patients treated with carbapenem and those treated with non-carbapenem antimicrobials for UTI caused by ESBL-producing Enterobacteriaceae. Therefore, the initially administered non-carbapenem can be maintained in UTI patients showing clinical improvement.

Clinical and Epidemiological Characteristics of Human Metapneumovirus Infections, in Comparison with Respiratory Syncytial Virus A and B / 소아감염

PURPOSE: To identify the clinical and epidemiological characteristics of human metapneumovirus infections (hMPV) in children compared to respiratory syncytial virus A (RSV A) and B (RSV B). METHOD: A retrospective review of medical records was performed in 36 patients with hMPV infection, 106 with RSV A infection, and 51 with RSV B infection, from September 2007 to July 2012. RESULTS: The peak incidence of hMPV infection was observed in May, whereas for RSV infections in November and December. hMPV infection occurred in older patients compared to RSV A and B infection (29.9+/-32.5 months vs. 13.6+/-15.4 months, P<0.001; 29.9+/-32.5 months vs. 12.1+/-13.5 months, P<0.001, respectively). hMPV infection was more often associated with fever compared to RSV A (97.2% vs. 67.9%, P<0.001), while wheezing was less frequent compared to RSV A and B infection (16.7% vs. 47.2%, P=0.001; 16.7% vs. 37.3%, P=0.037, respectively). hMPV infection was more often diagnosed as pneumonia compared to RSV A infection (72.2% vs. 50.0%, P=0.047) while bronchiolitis was less frequent than in RSV A (5.6% vs. 34.9%, P=0.001) or RSV B infection (5.6% vs. 29.4%, P=0.006). In addition, intravenous antibiotic was more often prescribed for patients with hMPV infection than those with RSV A and B (69.4% vs. 39.6%, P=0.002; 69.4% vs. 43.1, P=0.015, respectively). CONCLUSION: This study identified characteristics of hMPV infection compared to RSV A and B infection. Seasonality in spring, higher age group, and higher proportion of pneumonia in hMPV infections may be a useful guide for management of respiratory viral infections in children.

Isolation, characterization, and evaluation of Bacillus thuringiensis isolated from cow milk / 대한수의학회지

Probiotics colonize the intestines and exert an antibacterial effect on pathogens. Therefore, probiotics could be used as a preventive agent against lethal infections. To isolate probiotic microorganisms, 116 bacterial strains were isolated from healthy cow's milk and were subjected to Gram-stain, morphology and biochemical analyses, Vitek analysis, and 16S rRNA analysis. One of the strains identified as Bacillus (B.) thuringiensis 87 was found to grow very well at pH 4.0~7.0 and to be resistant to high concentrations of bile salts (0.3~0.9% w/v). B. thuringiensis was susceptible to the antibiotics used in the treatment of bovine mastitis, yet it exhibited an antimicrobial effect against Staphylococcus (S.) aureus 305. Moreover, it protected mice from experimental lethal infections of E. coli O55, Salmonella typhimurium 01D, and S. aureus 305 through a significant induction of interferon-gamma, even at four-week post-administration of B. thuringiensis. Although oral administration of B. thuringiensis 87 did not provide significant protection against these lethal challenges, these results suggest that B. thuringiensis 87 could be a feasible candidate as a probiotic strain.

Changes in Serotype Distribution and Antibiotic Resistance of Nasopharyngeal Isolates of Streptococcus pneumoniae from Children in Korea, after Optional Use of the 7-Valent Conjugate Vaccine

We investigated serotype distribution and antimicrobial resistance of pneumococcal carriage isolates from children after optional immunization with the 7-valent pneumococcal conjugate vaccine (PCV7) in Korea. From June 2009 to June 2010, 205 (16.5%) pneumococcal isolates were obtained from 1,243 nasopharyngeal aspirates of infants and children at Seoul National University Children's Hospital, Korea. Serotype was determined by Quellung reaction and antibiotic susceptibility was tested by E-test. The results were compared to previous studies done in the pre-PCV7 period. In this study, the most common serotypes were 6A (15.3%), 19A (14.7%), 19F (10.2%), 35B (7.3%), and 6D (5.6%). The proportion of PCV7 serotypes decreased from 61.9% to 23.8% (P < 0.001). The overall penicillin nonsusceptibility rate increased from 83.5% to 95.4% (P = 0.001). This study demonstrates the impact of optional PCV7 vaccination in Korea; the proportion of all PCV7 serotypes except 19F decreased while antimicrobial resistant serotypes 6A and 19A further increased.