• The Korean Journal of Applied Statistics
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• v.14 no.1
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• pp.1-11
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• 2001

In PPS sampling, measure of size(MOS) is used to determine the probability of selection of sampling unit. However, some large scale surveys conducted in NSO(National Statistical Office) showed that the sampling units have the similar MOS. In such case, simple cluster sampling method instead of PPS sampling is recommended to give the interviewers a similar work load. In this paper, MSE and CV of the above two sampling methods applied to the 1997 Economically Active Population Survey sample design are compared.

• The Korean Journal of Mycology
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• v.19 no.2
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• pp.136-142
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• 1991

Colonial morphology of the various yeasts grown on the yeast morphology agar me­dium containing orange-yellow pigments extracted from the fruits of Gardenia jasminoides (GJPM) was investigated in hopes of the differential identification of yeasts on primary cultures. Colonies of Candida lusitaniae and Ca. guilliermondii on GJPM turned to prussian blue within three days of incubation and Ca. tropicalis and Ca. viswanathii turned to bluish gray but the latter species turned to deep blue after 7 days. Ca. krusei, Saccharomyces cerevisiae, and Torulopsis glabrata showed neutral gray, grayish green, and baby blue respectively after one or two weeks. However, the colonies of Ca. albicans and parapsilosis remained unchanged even after 20 days. Colonial color of Cryptococ­cus neoformans showing brown to purple brown was distinguishable not only from buff color of Cr. laurentii after one or two weeks incubation but also from those of Candida spp. Growth of certain species was promoted on GJPM. The findings clearly showed that Ga. jasminoides pigments medium was useful to the morphological differentiation of medically important yeasts which were often encountered in sputum or other clinical specimens.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.39-46
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• 2005

Background : Even though it has been suggested that low-colony, scotochromogen nontuberculous mycobacteria (NTM) are usually contaminants and not true pathogens, evidence for this hypothesis has not been provided. This study investigated the colony characteristics, organism identification, and clinical significance of low-colony scotochromogen. Methods : The laboratory cultured 6,898 respiratory clinical specimens for an examination of mycobacteria over a three-month period. A low-colony count was arbitrarily defined as ${\leq}20$ colonies. This study analyzed the recovery rate of the mycobacteria, the number of colonies and their gross characteristics, and their clinical significance. PCR-restriction fragment length polymorphism analysis was carried out to identify the NTM species. NTM pulmonary disease was defined according to the American Thoracic Society. Results : A total of 6,898 respiratory specimens for mycobacterium were cultured. Of these, 263 (3.8%) grew NTM, and 382 (5.5%) grew M. tuberculosis. Of the 263 cultured NTM specimens, 124 (47.1%) were scotochromogens. The smear-positive rate was significantly lower in these scotochromogens (4.8%) than in the non-scotochromogens (23.7%) (p<0.05). The most common isolates were M. gordonae (83/102, 81.4%) in the scotochromogens, and MAC (52/121, 43.0%) in the non-scotochromogens. Even though three out of 113 patients with a low-colony scotochromogen has been diagnosed with NTM pulmonary disease, the isolated scotochromogen was not considered to be the cause of the NTM disease but was just a contaminant. Conclusion : In this study, the most common isolate of a low-colony count scotochromogen was M. gordonae, which appeared to be contaminants and not true pathogens. Greater efforts in the quality control of a mycobacterium laboratory are needed in cases where there is a high recovery rate of low-colony count scotochromogen.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.2
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• pp.83-89
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• 2015

Although Mycobacterium tuberculosis complex strains remain responsible for the majority of diseases caused by mycobacterial infections worldwide, the increase in HIV (human immuno deficiency virus) infections has allowed for the emergence of other non-tuberculous mycobacteria as clinically significant pathogens. M. tuberculosis was detected by two-tube nested polymerase chain reaction (PCR) and non-tuberculous mycobacteria was detected by PCR-restriction fragment length polymorphism (RFLP) with Msp I. Result of niacin test is equal to result of two-tube nested PCR after culture for M. tuberculosis. In this study, acid fast bacilli stain (AFB. stain) >2+ case, Detection of Mycobacteria is similar to result before culture and after culture. AFB. stain <1+ case, result of mycobacteria is distinguished. Conclusionly, these results suggest that identification of mycobacteria must go side by side both culture and PCR for more fast and accuracy.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.297-303
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• 2000

Gamma irradiation at 20 kGy was applied to Kanjang (soy sauce), Doenjang (soybean paste), Kochujang (hot pepper pasts) and Chungkukjang for their possible genotoxicity. The genotoxicity of 20 kGy-irradiated samples was evaluated by Salmonella typhimurium reversion assay. The Salmonella tester strains included TA98, TA100, TA1535 and TA1537 in the absence and presence of an exogenous metabolizing system (59 mix). All samples were negative in the bacterial reversion assay with S. typhimurium TA98, TA100, TA1535 and TA1537. The results indicated that 20 kGy of gamma irradiation on water-soluble fraction of Kanjang, Doenjang, Kochujang and Chungkukjang were not shown mutagenicity.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.682-693
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• 1995

• Food Science of Animal Resources
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• v.28 no.3
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• pp.355-362
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• 2008

This study was carried out to assess the fermentation properties of lactic acid bacteria (LAB) isolated from bovine colostrum and effects of feeding fermented colostrum feed on the growth to piglet. A total of 427 colonies were isolated from bovine colostrum on the BCP plate count agar. These LAB isolated were subcultured in 10% reconstituted skim milk, and seven strain thereof were selected for their highest acid productions, and two strain thereof were finally selected for their excellent sugar utilization. These strains were identified as Streptococcus thermophilus and Streptococcus macedonicus based on l6S rDNA sequencing data, named S. thermophilus CNB-11 and S. macedonicus CNB-11 respectively. For fermentation profiles, sugar utilization, acid production and viable cell counts were excellent in S. thermophilus CNB-11 as compared with S. macedoniclts CNB-11 after 48 hour. The effect of feeding fermented colostrum feed 0.5% using S. thermophilus CNB-11 was investigated for growth rate, analysis of blood and incidence of diarrhea. 24 heads of piglets were divided into two groups: the experimental and the control of 12 animals each. The average growth rate in the pigs fed fermented colostrum feed was higher 16.73% compared with control diet (p<0.05). There were no differences in the concentrations of blood glucose, cholesterol, albumin and globulin in pigs fed fermented colostrum feed as compared with control piglets. Incidence of diarrhea was no in pigs fed fermented colostrum feed as compared with control piglets.

• Journal of fish pathology
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• v.11 no.2
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• pp.143-150
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• 1998

Characteristics and distribution of the natural commensal flora in the surrounding environment and tissues of clam in Hadong area were studied under varying conditions of growth media and incubation temperatures. Total numbers of bacteria present in intestinal tract, gill, body fluid and surrounding mud were found to be not influenced by the used BHIA, STA and SNA media. Although the growth rate of bacteria at the condition of $15^{\circ}C$ incubation temperature was slower than that of $25^{\circ}C$ and $35^{\circ}C$, it showed the highest number of total bacteria compared with other two different conditions of incubation temperature. Interestingly, the proportion of bacteria able to form colony on several selective media was higher in replica analysis from nutrient media to selective media than that in direct smearing from samples. The generic diversity of bacteria isolated from the tissues and analyzed by API 20E and API 20NE kit showed similar pattern with each other and distinct from that of environment. The distribution of bacteria in the surrounding mud or mantle fluid of clam indicated a high diversity comparable to that found for the gill or intestinal tract microflora, with Pseudomonas being the prevalent group. It implies that the tissues of clam may probide a selective habitat for a commensal microflora.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.1
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• pp.375-382
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• 2010

The purpose of this study was to evaluate suppression of Streptococcus mutans(S. mutans) colonization by long-term xylitol consumption among pregnant women who can easily get bad oral hygiene status during pregnancy and breast feeding. Participants were voluntarily recruited for a pregnant women's oral health prevention program, classified into two groups(a control and a xylitol group), and then followed for 18 months. Stimulated whole saliva was collected in the afternoon(1:00-3:00 p.m.) at baseline, 6 months, 12months, and 18 months. Information regarding oral health behavior(tooth brushing frequency and regular dental visits) was obtained via a questionnaire. S. mutans counts of the xylitol group decreased considerably between baseline and the re-examinations at 6, 12, and 18 months. Although the S. mutans counts decreased for all time points compared to baseline in the control group, these differences did not reach significance except 18 months. Regular chewing of xylitol gum over a long period may lead to decrease the colony counts of S. mutans.

• Korean Journal of Microbiology
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• v.47 no.4
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• pp.335-341
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• 2011

In this study, 22 clinical isolates of Enterobacteriaceae including Citrobacterfreundii (6 strains), Enterobacter cloacae (5 strains), Enterobacter aerogenes (3 strains), Serratia marcescens (7 strains) and Pantoea spp. (1 strain) were investigated for the biofilm forming ability and biosynthesis of curli and cellulose. Biofilm forming ability was the highest among the isolates of E. cloacae and the lowest among the isolates of E. aerogenes. The expression of the biofilm-forming extracellular matrix components, cellulose and curli fimbriae, was examined by Congo-red (CR) staining and calcofluor staining methods. PCR screening for the presence of curli gene (csgA) revealed that 4 strains of E. cloacae and 1 strain of C. freundii carried the csgA, showing a good correlation between the phenotypic detection of curli fimbriae by CR staining method and the genotypic detection of curli gene by PCR in E. cloacae.