• Korean Journal of Clinical Laboratory Science
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• v.55 no.3
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• pp.151-158
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• 2023

Erythritol is a sweetener produced by yeast from glucose and a natural sugar found in fermented foods such as mushrooms, wine, fruits, rice wine, and soy sauce. Correct information and basic data when producing or using products for preventing dental caries by checking the gene expression patterns of glucosyl transferase (GTF) and fructosyl transferase (FTF) of Streptococcus mutans in erythritol and other sweeteners it was implemented to provide. Erythritol inhibited the growth of Streptococcus mutans, which is involved in dental caries. When used as a sweetener to replace sucrose, erythritol had an excellent caries-preventative effect. In particular, erythritol reduced the expressions of gtfB, gtfC, gtfD, and FTF, which are related to the synthesis of extracellular polysaccharides, and thereby reduced the formation of dental plaque and the attachment rate of bacteria to tooth surfaces. The study shows erythritol has potential use as an anticariogenic sweetener that inhibits the mechanism underlying caries caused by Streptococci.

• Clinical and Experimental Pediatrics
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• v.50 no.1
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• pp.56-64
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• 2007

Purpose : This study was performed to identify the etiologic agents and antimicrobial susceptibility patterns of organisms responsible for bloodstream infections in pediatric cancer patients for guidance in empiric antimicrobial therapy. Methods : One hundred and ninety-seven episodes of bloodstream infections that developed in 128 pediatric cancer patients were analyzed, which were identified at the Seoul National University Children's Hospital during a 4 year-period from 2002 to 2005. Results : A total of 214 pathogens was isolated, of which 64.0 percent were gram-negative, 31.3 percent were gram-positive bacteria, and 4.7 percent were fungi. The most common pathogens were Klebsiella spp. (21 percent) and Escherichia coli (16.8 percent), and coagulase-negative staphylococci (CNS, 7.9 percent) and viridans streptococci (7.5 percent) emerged as important pathogens. Neutropenic patients were more often associated with gram-negative bacteria than non-neutropenic patients (67.5 percent vs. 51.1%, P=0.018) and patients with central venous catheters were more often associated with CNS and viridans streptococci than those without. Resistance rates of gram-positive bacteria to penicillin, oxacillin and vancomycin were 83.3 percent, 48.5 percent and 0.5 percent, respectively, and those of gram-negative bacteria to cefotaxime, piperacillin/tazobactam, imipenem, gentamicin and amikacin were 24.1 percent, 17.2 percent, 6.6 percent, 21.6 percent, and 14.2 percent, respectively. Gram-negative bacteremias were more often associated with intensive care than gram-positive bacteremias (26.5 percent vs. 10.3 percent, P=0.016), and patients with catheters were more often associated with intensive care (34.4 percent vs. 10.8 percent, P<0.001) and higher fatality rate (16.7 percent vs. 4.8 percent, P=0.012) than those without. Conclusion : This study revealed that gram-negative bacteria are still a dominant organism in bloodstream infections, especially in neutropenic patients, and confirmed that gram-positive bacteria are emerging as important etiological agents in bloodstream infections of pediatric hemato-oncologic patients.

• Pediatric Infection and Vaccine
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• v.8 no.2
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• pp.206-212
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• 2001

Objective : To determine the clinical and bacteriologic efficacy and safety of Cefprozil in acute pharyngitis and pharyngotonsilitis caused by Group A beta hemolytic streptococci in pediatric patients. Methods : Any patient of 3 to 14 age who visited the hospitals enrolled in this study with the signs and symptoms of pharyngitis or pharyngotonsilitis since July, 2000 to March, 2001, was taken throat culture and given Cefprozil(15 mg/kg/day, in two divided doses) for 10 days. 138 patients of whom showed positive culture results were followed up for the signs and symptoms during the treatment to determine clinical efficacy. Any undesirable effect was reported to determine the safety of the drug. Follow up cultures were done at the end of the study and bacteriologic efficacy was determined. Results : 138 of 256 patients who visited the hospitals with the signs and symptoms of pharyngitis or pharyngotonsilitis showed positive growth on throat culture. Mean age of the patients was $6.1{\pm}2.5$ and males and females were equally numbered. 129 of them complained fever on the first visit and 112(86.6%) of them were improved at the end of the study. Cervical lymphadenitis was seen in 58 patients and 44(75.9%) of them improved at the end of the study. Exudative pharyngitis was seen in 96 patients and 81(84.3%) of them improved. The overall clinical effcacy based on this results showed that 110(79.7%) of the patients were cured and 17(12.3%) of them improved. On the cultures and bacteriologic efficacy, 24.6% of them showed documented eradication after treatment and 62.3% of them showed presumptive eradication. Sensitivity test was done by agar dilution method and Cefprozil showed 100% sensitivity. Erythromycin, Clarithromycin and azithromycin showed 87%, 85.6 %, 90.6% sensitivity, respectively. Conclusion : Cefprozil is proved to be effective in controlling group A streptococcal pharyngitis and pharyngotonsilitis in children and showed good sensitivity. Cefprozil can be used as an effective oral cephalosporin in the patients showing penicillin hypersensitivity or patients who other drugs have failed.

• Pediatric Infection and Vaccine
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• v.7 no.1
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• pp.143-151
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• 2000

Purpose : The accuracy of bacteriologic diagnosis of beta-hemolytic streptococcal pharyngotonsillitis depends on the degree of carrier rate in that area where the throat swabs are obtained and the evaluation of serological T typing as an epidemiologic marker is important to understand epidemiology of streptococcal infection. The purpose of this study is to know the carrier rates of group A streptococcus in normal children form four different areas and to find out the epidemiologic characteristic in distribution of the serotypes for 3 years. Method : Throat swabs were obtained from the tonsillar fossa of normal school children in four different areas(Uljin, Seoul, Osan, Kunsan) from March to May 1996, in Uljin in April 1997, and in Uljin in April 1998. The samples were plated on a 5% sheep blood agar plate and incubated overnight at $37^{\circ}C$ before examination for the presence of beta-hemolytic colonies. All isolated beta-hemolytic streptococcus were grouped and serotyped by T agglutination. Results : The carrier rate of beta-hemolytic streptococci and group A streptococci in 1996 were 27.6%, 18.6% at Uljin; 16.4%, 2.7% at Seoul; 33.0%, 26.0% at Osan; 20.0%, 12.3% at Kunsan, respectively. Among 1,192 normal school children from 4 different areas, we obtained 179 strains of group A streptococci. Fifty two percent of the strains were typable by T agglutination in 1996. Common T-type in 1996 were NT, T1, T3, T2 at Uljin; T12, T25 at Seoul; NT, T6, T28 at Osan; T25, T4, NT, T5 at Kunsan, in decreasing order, respectively. At Uljin, T1, T3, T25 accounted for 69% of strains in 1996, T1, T12, T25 accounted for 70% in 1997, and T12, T4 accounted for 88% in 1998. Conclusion : Higher carrier rates were found in Uljin and Osan, where there are a lower population density with scanty of medical facilities compared with another areas. We supposed that low carrier rates is likely to be related to antibiotic abuse or some epidemiologic factor. The periodic and seasonal serotyping analysis is important in monitoring and understanding the epidemiologic patterns of group A streptococci.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.407-412
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• 2017

The aim of this study was to shorten the time required for subculture and bacterial identification and obtain a simple and rapid identification method for new test methods for bloodstream infections. The following results were obtained using a mass spectrometer. In Vitek 2, 208 (81.8%) cases were well-identified and 45 isolates were not identified in blood cultures. Among 208 cases, 146 (57.5%) were Gram positive bacteria and 108 (42.5%) were Gram negative bacteria. In total, 233 were identified to the species level and 21 were identified to the genus level. The identification error was found to be Propionibacterium acnes as Clostridium bifermentans. The accuracy of Enterobacteriaceae, glucose non-fermentative bacilli (GNFB), and staphylococci were 81/83 (97.6%), 12/15 (80.0%), and 72/85 (84.7%), respectively. The concordance rate of Vitek 2 and Vitek MS by the direct method was 81.8% and 45 isolates were not identified. Most of the unidentified bacteria were Gram positive bacteria (N=37). The Gram positive bacteria were streptococci (14), coagulase-negative staphylococci (CNS) (11), enterococci (3), Staphylococcus aureus (2), Micrococcus spp. (2), Bacillus spp. (2) and Actinomyces odontolyticus, Finegoldia magna, and Peptostreptococcus spp. The results reporting time was reduced to 24~72 hours compared to the conventional method. The rate of identification of the aerobic and anaerobic cultures was similar, but the use of an anaerobic culture did not require a dissolution process, which could shorten the sample preparation time. These results suggest that the method of direct identification in blood cultures is very useful for the treatment of patients. In further studies, it might be necessary to further improve the method for identifying streptococci and CNS, which were lacking in accuracy in this study.

• Journal of the korean academy of Pediatric Dentistry
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• v.30 no.4
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• pp.554-562
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• 2003

Xylitol has been used as sugar substitute to prevent dental caries. It is not fermented by most dental plaque bacteria and interferes with the growth of mutans streptococci. Therefore the production of acidic metabolites and the growth of mutans streptococci are inhibited. S. mutans strains which are inhibited to grow under the presence of xylitol are referred as xylitol-sensitive ($X^S$) strains. However, experimental and clinical studies have shown that there were mutated groups of S. mutans strains that are not affected by xylitol. They are referred as xylitol-resistant($X^R$) strains. The aim of the present study was to investigate that emergence of $X^R$ strain would effect on the anticariogenecity of xylitol by comparing the growth rate, the extracellular pH, hydroxyapatite adhesion and the agglutination of the $X^R/X^S$ strains. Overall we came out with following results : 1. No difference in the growth rate and the extracellular pH was found between the $X^S$ strain and the $X^R$ strain. 2. No difference in adhesion to hydroxyapatite surface was found between the $X^R$ strain and the $X^S$ strain (p>0.05) and adhesion of the $X^S$ strain was greater than that of $X^R$ strain in the sucrose-dependent adhesion to hydroxyapatite (p<0.05). 3. The $X^R$ strain was agglutinated in the lower concentration of saliva than that of $X^S$ strains.

• Journal of Preventive Medicine and Public Health
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• v.7 no.1
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• pp.175-176
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• 1974

The purpose of this study was to survey bacteria which was known as a fecal bacteria living in the human and animal gastro and intestinal tract. The colony density of the fecal coliform and fecal streptococci was 280 and 130 in 100ml sample amounts reapectively. Staphylococcus aureus and Pseudomonas aeruginosa which is usually exist in swimming pool and was known as indicator of the pool water contamination was detected.

• Journal of the korean academy of Pediatric Dentistry
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• v.8 no.1
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• pp.47-53
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• 1981

Author have studied with electron microscope on the effect of biscuit solution dissolved in natural saliva on the enamel surface of the primary teeth. Four of the teeth were natural primary teeth and the other four teeth were treated in acidulated phosphate fluoride during four minute. The obtained results were as follows; 1. The pH value of the solution was decreased according to the time passed, and gradually became 3.75 at the end of 48 hours. 2. Natural teeth appeared normal enamel surface appearance during first 12 hours, and at 24 hours, it appeared some degree of decalcified appearance near the enamel rods and surfaces. 3. The decalcified appearances of the enamel surfaces of the fluoride treated teeth were not significant compared with the fluoride untreated teeth. 4. Streptococci of the enamel surface were increased according to the time passed.

• Korean Journal of Environmental Biology
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• v.20 no.3
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• pp.189-196
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• 2002

The direct detection of intestinal pathogens and viruses often requires costly, tedious, and time-consuming procedures. These requirements developed a test to show that the water was contaminated with sewage-borne pathogens by assessing the hygienic quality of water based on indicator microorganisms whose presence indicates that pathogenic microorganisms may also be present. Various groups of microorganisms have been suggested and used as indicator microorganisms. Proposed and commonly used microbial indicators are total coliforms, fecal coliforms, fecal streptococci, Clostridium perfringens, heterotrophic plate count, bacteriophage, and so on. Unfortunately, most, if not all, of these indicators are not ideal because of the sensitivity and resistance to environment stresses and disinfection. However, the development of gene probes and PCR technology may give hope for the discovery of rapid and simple methods toy detecting small number of fecal pathogens in various environments.

• Pediatric Infection and Vaccine
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• v.2 no.1
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• pp.110-115
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• 1995

Authors have experienced a case of neonatal sepsis whose organisms were group B streptococci. This case was early-onset type and the two premature babies were expired. Autopsy was done but no specific findings were shown in pulmonary parenchyma except focally mild atelectasis and dilated bronchiols and alveoli, and distictive hyaline membrane or aspirated materials are not identified. A brief review follows.