Role of 16S Ribosomal RNA Analysis in Identification of Microorganisms in Febrile Urinary Tract Infection of Infants.

OBJECTIVES: To assess the role of 16S ribosomal RNA analysis in microbial identification in febrile infants under six months of age diagnosed with UTI, and compare it with the conventional culture results. METHODS: Young infants under 6 mo of age who were suspected UTI from May 2018 to April 2019 had been enrolled. Uropathogens were analyzed by the traditional microbiologic culture system and the 16S rRNA analysis. The 16S rRNA analysis included 16S rRNA amplicon band confirmation and bacterial identification through the sequencing analysis. RESULTS: A total of 57 infants with the febrile UTI were enrolled, and the median age was 3 mo. Uropathogens were identified in 43 patients (75.4%) in a conventional culture method: Escherichia coli in 38 patients (88.4%), Klebsiella pneumoniae in 3 (7.0%), Enterobacter cloacae in 1 (2.3%), and Pseudomonas aeruginosa in 1 (2.3%). Fifty urine samples (87.8%) had positive 16S rRNA amplicon band on electrophoresis. Among the 16S rRNA-positive urines, 40 samples were available for the sequence analysis of 16S rRNA, and the identification of bacteria were as follows: E. fergusonii in 36, K. pneumoniae in 3, and Shigella flexneri in 1. The sensitivity of 16S rRNA sequencing was 81.4% [95% confidence interval (CI), 67.4-90.3%] and the specificity was 64.3% (95% CI, 38.8-83.7%). CONCLUSION: Uropathogen identification using 16S rRNA analysis could be applied to manage the febrile UTI in young infants clinically in combination with the conventional culture.

Retinopathy of Prematurity Requiring Treatment Is Closely Related to Head Growth during Neonatal Intensive Care Unit Hospitalization in Very Low Birth Weight Infants.

BACKGROUND: Retinopathy of prematurity (ROP) is caused by prenatal sensitization and postnatal insults to the immature retina. This process can be associated with the postnatal growth of preterm infants. We investigated whether ROP requiring treatment was associated with the postnatal growth failure of very low birth weight (VLBW) infants. METHOD: From a cohort of VLBW infants (birth weight <1,500 g) registered in the Korean Neonatal Network from January 2013 to December 2017, 3,133 infants with gestational age (GA) between 24 and 28 weeks were included in the study. Postnatal growth failure was defined when the change in each anthropometric z-score between birth and discharge was <10th percentile of the total population. Propensity score matching (PSM) at 1:1 was performed to match the distribution of GA and postnatal morbidities between infants with and without ROP requiring treatment. Prenatal factors and ROP were analyzed by conditional logistic regression. RESULTS: Of 3,133 enrolled infants, 624 (19.9%) were diagnosed with ROP requiring treatment. After PSM, ROP requiring treatment was associated with postnatal growth failure assessed by head circumference (adjusted odds ratio [aOR] 1.91, 95% confidence interval [CI] 1.18-3.09), but not weight (aOR 1.45, 95% CI 0.97-2.17) and length (aOR 1.21, 95% CI 0.81-1.82). CONCLUSION: ROP requiring treatment was associated with poor head circumference growth, not with weight and length. Our findings suggest that ROP requiring treatment and poor head growth during NICU hospitalization are fundamentally related.

Direct swallowing training and oral sensorimotor stimulation in preterm infants: a randomised controlled trial.

OBJECTIVE: To evaluate the effects of direct swallowing training (DST) alone and combined with oral sensorimotor stimulation (OSMS) on oral feeding ability in very preterm infants. DESIGN: Blinded, parallel group, randomised controlled trial (1:1:1). SETTING: Neonatal intensive care unit of a South Korean tertiary hospital. PARTICIPANTS: Preterm infants born at <32 weeks of gestation who achieved full tube feeding. INTERVENTIONS: Two sessions per day were provided according to the randomly assigned groups (control: two times per day sham intervention; DST: DST and sham interventions, each once a day; DST+OSMS: DST and OSMS interventions, each once a day). PRIMARY OUTCOME: Time from start to independent oral feeding (IOF). RESULTS: Analyses were conducted in 186 participants based on modified intention-to-treat (63 control; 63 DST; 60 DST+OSMS). The mean time from start to IOF differed significantly between the control, DST and DST+OSMS groups (21.1, 17.2 and 14.8 days, respectively, p=0.02). Compared with non-intervention, DST+OSMS significantly shortened the time from start to IOF (effect size: -0.49; 95% CI: -0.86 to -0.14; p=0.02), whereas DST did not. The proportion of feeding volume taken during the initial 5 min, an index of infants' actual feeding ability when fatigue is minimal, increased earlier in the DST+OSMS than in the DST. CONCLUSIONS: In very preterm infants, DST+OSMS led to the accelerated attainment of IOF compared with non-intervention, whereas DST alone did not. The effect of DST+OSMS on oral feeding ability appeared earlier than that of DST alone. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov Registry (NCT02508571).

Association of Severe Retinopathy of Prematurity and Bronchopulmonary Dysplasia with Adverse Neurodevelopmental Outcomes in Preterm Infants without Severe Brain Injury.

Although impaired neurodevelopment is strongly associated with severe brain injury, most preterm infants survive without severe brain injury. In this study, the association of impaired neurodevelopment and neonatal morbidities of preterm infants was assessed after excluding those with severe brain injury. This was a retrospective study of very low birthweight infants in a single tertiary center. After excluding infants with severe brain injury, the study population was categorized as infants without intraventricular hemorrhage (IVH) and with low-grade IVH. Neurodevelopmental outcomes at a corrected age (CA) of 18-24 months were evaluated using the Bayley Scales of Infant and Toddler Development 3rd Edition (Bayley-III). Cerebral palsy (CP), hearing impairment and blindness were also assessed and compared. Of 240 infants, 25 (11.6%) infants had combined neurodevelopmental impairment (NDI). In the multivariate analysis for combined NDI, small for gestational age (SGA) (adjusted OR 6.820, 95% confidence intervals (CI) 1.770-26.307), moderate to severe bronchopulmonary dysplasia (BPD) (aOR 3.21, 95% CI 1.032-9.999) and severe retinopathy of prematurity (ROP) (aOR 5.669, 95% CI 1.132-28.396) were associated with combined NDI. Among neonatal morbidities, moderate to severe BPD and severe ROP were associated with adverse neurodevelopmental outcomes in preterm infants without severe brain injury.

Time-Dependent Anti-Demineralization Effect of Silver Diamine Fluoride.

This study compared the demineralization resistance of teeth treated with silver diamine fluoride (SDF) to that treated with fluoride varnish. A total of 105 healthy bovine incisors were divided into control, fluoride varnish, and SDF groups. The enamel surface density change was then measured by micro-computed tomography (micro-CT) at three depths. The demineralized zone volume was measured on 3D micro-CT images to evaluate the total demineralization rate. The enamel surface morphology was assessed by scanning electron microscope. The enamel density had continuously decreased while demineralization increased in the control and fluoride varnish groups. The enamel density had increased in the SDF group till the 7th day of demineralization treatment and decreased thereafter. However, the decrease in the SDF group was less severe than that in the other groups (p < 0.05). The demineralized enamel volume had increased through treatment and was the highest in the control group, followed by the fluoride varnish and SDF group. The enamel surface morphology was the roughest and most irregular in the control group, followed by the fluoride varnish group and SDF groups.

New modified version of the Risk Adjustment for Congenital Heart Surgery category and mortality in premature infants with critical congenital heart disease.

BACKGROUND: Despite advances in neonatal intensive care and surgical procedures, perinatal mortality rates for premature infants with congenital heart disease (CHD) remain relatively high. PURPOSE: We aimed to describe the outcomes of premature infants with critical CHD and identify the risk factors including the new modified version of the Risk Adjustment for Congenital Heart Surgery (M-RACHS) category associated with in-hospital mortality in a Korean tertiary center. METHODS: This was a retrospective cohort study of premature infants with critical CHD admitted to the neonatal intensive care unit from January 2005 to December 2016. RESULTS: A total of 78 premature infants were enrolled. The median gestational age (GA) at birth was 34.9 weeks (range, 26.7-36.9 weeks), and the median birth weight was 1.91 kg (range, 0.53-4.38 kg). Surgical or percutaneous intervention was performed in 68 patients with a median GA at birth of 34.7 weeks (range, 26.7-36.8 weeks) and a median birth weight of 1.92 kg (range, 0.53-4.38 kg). The in-hospital survival rate was 76.9% among all enrolled preterm infants and 86.8% among patients who received an intervention. Very low birth weight (VLBW), persistent pulmonary hypertension of the newborn (PPHN), bronchopulmonary dysplasia (BPD), and M-RACHS category 5 or higher (more complex CHD) were independently associated with in-hospital mortality. For the 68 premature infants undergoing cardiac interventions, independent risk factors for mortality were VLBW, BPD, and CHD complexity. Late preterm infant and age at intervention were not associated with patient survival. CONCLUSION: For premature infants with critical CHD, VLBW, PPHN, BPD, and M-RACHS category ≥5 were risk factors for mortality. A careful approach to surgical intervention and prenatal care should be taken according to CHD type and neonatal condition.

Group B streptococcal transmission via a prolonged colonizer in a neonatal intensive care unit.

This article reports five invasive Group B streptococcal (GBS) infections that occurred in a neonatal intensive care unit for about 3 months. This outbreak might have been associated with a prolonged GBS colonized infant and adjacent environmental contaminations. Infection control interventions prevented the additional spread of GBS infections.

Comparative Pathogenicity of Fusarium graminearum Isolates from Wheat Kernels in Korea.

Fusarium head blight (FHB) caused by Fusarium species is a major disease of wheat and barley around the world. FHB causes yield reductions and contamination of grains with trichothecene mycotoxins including; nivalenol (NIV), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), and 15-acetylde-oxynivalenol (15-ADON). The objectives of this study were to identify strains of F. graminearum isolated in Korea from 2012-harvested wheat grain and to test the pathogenicity of these NIV- and DON-producing isolates. Three hundred and four samples of wheat grain, harvested in 2012 in Chungnam, Chungbuk, Gyeongnam, Jeonbuk, Jeonnam, and Gangwon provinces were collected. We recovered 44 isolates from the 304 samples, based on the PCR amplification of internal transcribed spacer (ITS) rRNA region and sequencing. Our findings indicate that F. asiaticum was the predominant (95% of all isolates) species in Korea. We recovered both F. asiaticum and F. graminearum from samples collected in Chungnam province. Of the 44 isolates recovered, 36 isolates had a NIV genotype while 8 isolates belonged to the DON genotype (3-ADON and 15-ADON). In order to characterize the pathogenicity of the strains collected, disease severity was assessed visually on various greenhouse-grown wheat cultivars inoculated using both NIV- and DON-producing isolates. Our results suggest that Korean F. graminearum isolates from wheat belong to F. asiaticum producing NIV, and both F. graminearum and F. asiaticum are not significantly different on virulence in wheat cultivars.

Serum high-density lipoprotein cholesterol concentration and functional state: The Korean Urban Rural Elderly (KURE) Study.

BACKGROUND: Functional state and cholesterol metabolism are important for older adults; however, this association has not been fully investigated among community-dwelling older adults. Thus, we investigated the association of HDL cholesterol with multiple functional state measures in an elderly Korean population. METHODS: This cross-sectional analysis included 3514 participants, aged 65 years or older, who participated in baseline health assessment for the Korean Urban Rural Elderly cohort study from 2012 to 2015. HDL cholesterol concentration was analyzed using both continuous and categorical variables. Functional state was assessed by the mini-mental state examination (MMSE), activities of daily living (ADL) scale, instrumental activities of daily living (IADL) scale, timed up-and go (TUG) test, and chair-rise test (CRT). Multiple logistic regression models were used to investigate independent association between HDL cholesterol and functional state, after adjusting for sex, age, body mass index, systolic blood pressure, fasting glucose, lipid-lowering drug, history of cancer and cardiovascular disease, and health behaviors. RESULTS: HDL cholesterol concentration was significantly associated with MMSE, ADL, IADL, TUG, and CRT in the unadjusted model. After adjustment for covariates, the association remained significant for MMSE (standardized ß=0.059, p=0.001), ADL (standardized ß=-0.053, p=0.004), and CRT (standardized ß=-0.037, p=0.037). In fully-adjusted model, Participants who had a lower HDL concentration (<40mg/dL) showed significantly increased odds for having MMSE decline (OR 1.451, 95% CI 1.119-1.883) and ADL dependency (OR 2.251, 95% CI 1.119-4.526), compared reference group (≥60mg/dL). CONCLUSIONS: Higher HDL cholesterol concentration was associated with better functional state among Korean older adults.

Comparison of Formulas for Calculating Low-density Lipoprotein Cholesterol in General Population and High-risk Patients with Cardiovascular Disease.

BACKGROUND AND OBJECTIVES: Low-density lipoprotein cholesterol (LDL-C), an established cardiovascular risk factor, can be generally determined by calculation from total cholesterol, high-density lipoprotein cholesterol, and triglyceride concentrations. The aim of this study was to compare LDL-C estimations using various formulas with directly measured LDL-C in a community-based group and hospital-based group among the Korean population. SUBJECTS AND METHODS: A total of 1498 participants were classified into four groups according to triglyceride concentrations as follows: <100, 100-199, 200-299, and ≥300 mg/dL. LDL-C was calculated using the Friedewald, Chen, Vujovic, Hattori, de Cordova, and Anandaraja formulas and directly measured using a homogenous enzymatic method. Pearson's correlation coefficients, intraclass correlation coefficients (ICC), Passing & Bablok regression, and Bland-Altman plots were used to evaluate the performance of six formulas. RESULTS: The Friedewald formula had the highest accuracy (ICC=0.977; 95% confidence interval 0.974-0.979) of all the triglyceride ranges, while the Vujovic formula had the highest accuracy (ICC=0.876; 98.75% confidence interval 0.668-0.951) in people with triglycerides ≥300 mg/dL. The mean difference was the lowest for the Friedewald formula (0.5 mg/dL) and the percentage error was the lowest for the Vujovic formula (30.2%). However, underestimation of the LDL-C formulas increased with triglyceride concentrations. CONCLUSION: The accuracy of the LDL-C formulas varied considerably with differences in triglyceride concentrations. The Friedewald formula outperformed other formulas for estimating LDL-C against a direct measurement and the Vujovic formula was suitable for hypertriglyceridemic samples; it could be used as an alternative cost-effective tool to measure LDL-C when the direct measurement cannot be afforded.

Serum uric acid concentration and metabolic syndrome among elderly Koreans: The Korean Urban Rural Elderly (KURE) study.

BACKGROUND: Epidemiologic studies have demonstrated that elevated serum uric acid concentration is an independent risk factor for metabolic syndrome. However, few studies have focused on elderly populations. Thus, we investigated the association of serum uric acid concentration with metabolic syndrome in community-dwelling elderly Koreans. METHODS: This cross-sectional analysis included 2940 participants (986 men and 1954 women) aged 65 years or older who participated in a baseline health assessment for the Korean Urban Rural Elderly cohort study from 2012 to 2014. Serum uric acid concentration was analyzed using both continuous and dichotomous variables. Hyperuricemia was defined as a uric acid concentration ≥7.0 mg/dL in men and ≥6.0 mg/dL in women. Metabolic syndrome was defined according to the 2009 harmonizing definition. Multiple logistic regression models were used to investigate independent association between serum uric acid and metabolic syndrome, after adjusting for age, body mass index, LDL cholesterol, glycated hemoglobin, blood urea nitrogen, estimated glomerular filtration rate health behaviors, and medications. RESULTS: Prevalence of metabolic syndrome and its components increased significantly according to uric acid concentration in both sexes. The adjusted odds ratios for having metabolic syndrome per 1.0mg/dL higher uric acid concentration were 1.16 (95% CI: 1.03-1.31) in men and 1.27 (95% CI: 1.13-1.42) in women. Hyperuricemia was also associated with metabolic syndrome, with adjusted odds ratios of 1.71 (95% CI: 1.11-2.63) in men and 1.55 (95% CI: 1.05-2.29) in women. CONCLUSIONS: Elevated serum uric acid concentration was independently associated with an increased prevalence of metabolic syndrome in community-dwelling elderly Koreans.

Continuous alkaline pretreatment of Miscanthus sacchariflorus using a bench-scale single screw reactor.

Miscanthus sacchariflorus 'Goedae-Uksae 1' (GU) was developed as an energy crop of high productivity in Korea. For the practical use of GU for bioethanol production, a bench-scale continuous pretreatment system was developed. The reactor performed screw extrusion, soaking and thermochemical pretreatment at the following operating conditions: 3 mm particle size, 22% moisture content, 140 °C reaction temperature, 8 min residence time, 15 g/min biomass feeding and 120 mL/min NaOH input. As a result of minimizing NaOH concentration and enzyme dosage, 90.8±0.49% glucose yield was obtained from 0.5 M NaOH-pretreated GU containing 3% glucan with 10 FPU cellulase/g cellulose at 50 °C for 72 h. The separate hydrolysis and fermentation of 0.5 M NaOH-pretreated GU containing 10% glucan with 10-30 FPU for 102 h produced 43.0-49.6 g/L bioethanol (theoretical yield, 75.8-87.6%). Thus, this study demonstrated that continuous pretreatment using a single screw reactor is effective for bioethanol production from Miscanthus biomass.

Urban-rural differences explain the association between serum 25-hydroxyvitamin D level and insulin resistance in Korea.

An increasing number of studies report associations between low serum 25-hydroxyvitamin D [25(OH)D] level and insulin resistance; however, whether low vitamin D levels directly contribute to increased insulin resistance is unclear. We investigated the impact of residential area on the association between 25(OH)D and insulin resistance in elderly Koreans. Using data from the Korean Urban Rural Elderly study, we conducted cross-sectional analyses in 1628 participants (505 men and 1123 women). Serum 25(OH)D was analyzed as both continuous and categorized variables. Homeostasis model assessment for insulin resistance (HOMA-IR) was calculated using fasting blood glucose and insulin levels. In men, 25(OH)D level was inversely associated with HOMA-IR (standardized ß = -0.133, p < 0.001) after adjustment for age, body mass index, waist circumference, smoking, alcohol intake, exercise, and study year. However, we noted significant urban-rural differences in 25(OH)D level (43.4 versus 65.6 nmol/L; p < 0.001) and HOMA-IR (1.2 versus 0.8 mmol · pmol/L2; p < 0.001). When we additionally adjusted for residential area, the association between 25(OH)D and HOMA-IR was attenuated (standardized ß = -0.063, p = 0.115). In women, the association between 25(OH)D and HOMA-IR was not significant before or after adjustment for residential area. Environmental or lifestyle differences in urban and rural areas may largely explain the inverse association between serum 25(OH)D and insulin resistance.

The optimized CO2-added ammonia explosion pretreatment for bioethanol production from rice straw.

A CO2-added ammonia explosion pretreatment was performed for bioethanol production from rice straw. The pretreatment conditions, such as ammonia concentration, CO2 loading level, residence time, and temperature were optimized using response surface methodology. The response for optimization was defined as the glucose conversion rate. The optimized pretreatment conditions resulting in maximal glucose yield (93.6 %) were determined as 14.3 % of ammonia concentration, 2.2 MPa of CO2 loading level, 165.1 °C of temperature, and 69.8 min of residence time. Scanning electron microscopy analysis showed that pretreatment of rice straw strongly increased the surface area and pore size, thus increasing enzymatic accessibility for enzymatic saccharification. Finally, an ethanol yield of 97 % was achieved via simultaneous saccharification and fermentation. Thus, the present study suggests that CO2-added ammonia pretreatment is an appropriate process for bioethanol production from rice straw.

A new genotype of Miscanthus sacchariflorus Geodae-Uksae 1, identified by growth characteristics and a specific SCAR marker.

Miscanthus is referred to as an ideal lignocellulosic bioenergy crop, which can be used to generate heat, power, and fuel, as well as to reduce carbon dioxide emissions. The new Miscanthus sacchariflorus genotype named Geodae-Uksae 1 was recently collected from damp land in southern Korea. This study investigated the growth characteristics of Miscanthus genotypes, and developed a specific, sensitive, and reproducible sequence characterized amplified region (SCAR) marker to distinguish new M. sacchariflorus genotype Geodae-Uksae 1 from other native Miscanthus species in Korea. Growth characteristics such as stem length, stem diameter, and dry weight of Geodae-Uksae 1 were greater than those of normal M. sacchariflorus. The genotypes within Geodae-Uksae 1 were had the highest genetic similarity. A putative 1,800-bp polymorphic sequence specific to Geodae-Uksae 1 was identified with the random amplified polymorphic DNA (RAPD) N8018 primer. The sequence-characterized amplified region (SCAR) primers Geodae 1-F and Geodae 1-R were designed based on the unique RAPD amplicon. The SCAR primers produced a specific 1,799-bp amplicon in authentic Geodae-Uksae 1, whereas no amplification was observed in other Miscanthus species. The SCAR marker could contribute to identify Geodae-Uksae 1 among native Miscanthus species. The new Miscanthus genotype Geodae-Uksae 1 has great potential as an alternative lignocellulosic biomass feedstock for bioenergy productions.

A study testing the usefulness of a dish-based food-frequency questionnaire developed for epidemiological studies in Korea.

The purpose of the present study was to test the usefulness of dish items selected in developing a dish-based FFQ (DFFQ) to be used for epidemiological studies in Korea. The dietary data of 6817 subjects from the 2001 Korean National Health and Nutrition Examination Survey were used for the analysis. The 24 h recall method was employed for the dietary survey. Initially, ninety-five dish items were selected in developing the DFFQ based on consumption frequency, contribution of selected nutrients and coverage of between-person variations. The usefulness of the selected ninety-five dish items was tested based on their degree of contribution in supplying nutrients in the cumulative percentage contribution (cPC), as well as on their degree of explanation for between-person variation in the cumulative regression coefficient (cMRC). According to the results, the ninety-five selected dish items accounted for an average of 92.3 % of seventeen nutrients consumed by the study subjects based on cPC estimation. The top twenty items among the ninety-five dish items covered 70 to 91 % of the between-person variation for the seventeen nutrients based on cMRC estimation. Thus, the results suggest that the ninety-five items would be useful in developing a FFQ for use in epidemiological studies of Koreans, within less than 10 % underestimation.