• Journal of Microbiology and Biotechnology
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• 제23권2호
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• pp.189-194
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• 2013

In a study of hydrogen-producing bacteria, strain T4384 was isolated from rice field samples in the Republic of Korea. The isolate was identified as Enterobacter sp. T4384 by phylogenetic analysis of 16S rRNA and rpoB gene sequences. Enterobacter sp. T4384 grew at a temperature range of $10-45^{\circ}C$ and at an initial pH range of 4.5-9.5. Strain T4384 produced hydrogen at 0-6% NaCl by using glucose, fructose, and mannose. In serum bottle cultures using a complete medium, Enterobacter sp. T4384 produced 1,098 ml/l $H_2$, 4.0 g/l ethanol, and 1.0 g/l acetic acid. In a pH-regulated jar fermenter culture with the biogas removed, 2,202 ml/l $H_2$, 6.2 g/l ethanol, and 1.0 g/l acetic acid were produced, and the lag-phase time was 4.8 h. Strain T4384 metabolized the hydrolysate of organic waste for the production of hydrogen and volatile fatty acid. The strain T4384 produced 947 ml/l $H_2$, 3.2 g/l ethanol, and 0.2 g/l acetic acid from 6% (w/v) food waste hydrolysate; 738 ml/l $H_2$, 4.2 g/l ethanol, and 0.8 g/l acetic acid from Miscanthus sinensis hydrolysate; and 805 ml/l $H_2$, 5.0 g/l ethanol, and 0.7 g/l acetic acid from Sorghum bicolor hydrolysate.

• Tuberculosis and Respiratory Diseases
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• 제84권3호
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• pp.237-244
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• 2021

Background: The emergence of drug-resistant tuberculosis (TB), is a major menace to cast off TB worldwide. Line probe assay (LPA; GenoType MTBDRplus ver. 2) and Xpert MTB/RIF assays are two rapid molecular TB detection/diagnostic tests. To compare the performance of LPA and Xpert MTB/RIF assay for early diagnosis of rifampicin-resistant (RR) TB in acid-fast bacillus (AFB) smear-positive and negative sputum samples. Methods: A total 576 presumptive AFB patients were selected and subjected to AFB microscopy, Xpert MTB/RIF assay and recent version of LPA (GenoType MTBDRplus assay version 2) tests directly on sputum samples. Results were compared with phenotypic culture and drug susceptibility testing (DST). DNA sequencing was performed with rpoB gene for samples with discordant rifampicin susceptibility results. Results: Among culture-positive samples, Xpert MTB/RIF assay detected Mycobacterium tuberculosis (Mtb) in 97.3% (364/374) of AFB smear-positive samples and 76.5% (13/17) among smear-negative samples, and the corresponding values for LPA test (valid results with Mtb control band) were 97.9% (366/374) and 58.8% (10/17), respectively. For detection of RR among Mtb positive molecular results, the sensitivity of Xpert MTB/RIF assay and LPA (after resolving discordant phenotypic DST results with DNA sequencing) were found to be 96% and 99%, respectively. Whereas, specificity of both test for detecting RR were found to be 99%. Conclusion: We conclude that although Xpert MTB/RIF assay is comparatively superior to LPA in detecting Mtb among AFB smear-negative pulmonary TB. However, both tests are equally efficient in early diagnosis of AFB smear-positive presumptive RR-TB patients.

• 한국어병학회지
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• 제36권2호
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• pp.277-286
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• 2023

Korean rockfish, Sebastes schlegelii, is a representative bony fish that belongs to the family Scorpaenidae and the order Scorpaeniformes. It has high ecological and economic value and is widely cultivated in many East Asian countries, including South Korea, Japan and China. One of streptococci, Streptococcus iniae, is Gram-positive cocci with a negative reaction for catalase and oxidase. The Korean rockfish shows clinical signs when infected with S. iniae, such as body darkening, bleeding, enlarged kidneys, blurred eyes, abdominal distension, etc., ultimately leading to death. The Korean rockfish causes significant economic losses every year in South Korea due to streptococcosis. In this study, we identified bacteria from the fish using polymerase chain reaction and conducted analyses of hemolytic activity and biochemical tests using API 20 STREP and API ZYM systems. Results of confirming the hemolytic activity (n=4) observed in alpha-type hemolysis (25%), beta-type hemol- ysis (50%), and gamma-type hemolysis (25%) of isolates. The biochemical test results exhibited sig- nificant variation among S. iniae. Additionally, we performed intraperitoneal injection with S. iniae in the fish and analyzed the phylogenetic tree using housekeeping genes of S. iniae, including cpsD, arcC, glnA, groEL, gyrB, mutS, pheT, prkC, rpoB, and tkt, via multilocus sequence typing (MLST). The lethal dose (LD₅₀) showed strong pathogenicity, such as 3.34 × 10 colony-forming unit (CFU)/ml for 23FBStr0601 strain and 7.16 × 10 CFU/ml for 23FBStr0602 strain. 23FBStr0603 strain showed relatively low pathogenicity at 1.73 × 10⁵ CFU/ml. The strains 23FBStr0601 and 23FBStr0602, which showed strong pathogenicity, clustered into one monophyletic group. The 23FBStr0603 strain showed weak pathogenicity and formed a monophyletic group with KCTC 3657.

• Tuberculosis and Respiratory Diseases
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• 제74권4호
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• pp.191-194
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• 2013

Mycobacterium chelonae lung disease is very rare. We report a case of lung disease caused by M. chelonae in a previously healthy woman. A 69-year-old woman was referred to our hospital because of hemoptysis. A computed tomography (CT) scan of the chest revealed bronchiolitis associated with bronchiectasis in the lingular division of the left upper lobe. Nontuberculous mycobacteria were isolated three times from sputum specimens. All isolates were identified as M. chelonae by various molecular methods that characterized rpoB and hsp65 gene sequences. Although some new lesions including bronchiolitis in the superior segment of the left lower lobe developed on the chest CT scan 35 months after diagnosis, she has been followed up without antibiotic therapy because of her mild symptoms. To the best of our knowledge, this is the first case of M. chelonae lung disease in Korea in which the etiologic organisms were confirmed using molecular techniques.

• Tuberculosis and Respiratory Diseases
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• 제59권6호
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• pp.606-612
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• 2005

배 경: 최근 국내의 연구에 의하면 객담 항산균 도말검사에 양성을 보인 환자들 중 NTM 분리비율이 약 10%정도로 NTM 폐질환의 중요성이 증가하고 있다. 국립 마산 결핵 병원의 경우 타 병원에 비해 초치료 환자 보다 재치료 및 다제 내성 결핵 환자의 비율이 높고 이런 환자들에 있어서 NTM 폐질환의 여부 및 원인균에 대한 연구가 필요할 것으로 생각된다. 대상 및 방법 : 2002년 8월부터 2003년 7월까지 본원에서 객담 및 기관지 세척액 등 호흡기 검체를 통해 항상균 도말 및 배양검사가 의뢰된 검체에서 NTM이 분리된 환자들을 대상으로 하였다. NTM 폐질환의 진단은 미국흉부학회 진단 기준을 이용하였으며 환자들의 원인균, 임상적 및 방사선적 특징과 NTM 폐질환 발생과 치료성공에 연관된 인자에 대하여 후향적으로 조사하였다. 결 과 : 57명의 환자로부터 의뢰된 100개의 호흡기 검체에서 NTM균이 분리되었다. 미국 흉부학회의 NTM 폐질환 진단 기준에 따라 57명의 환자 중 26명(45.6%)가 NTM 폐질환을 가지고 있었으며 원인균은 M. intracellulare 19명(73.1%), M. abscessus 5명(19.2%), M. fortuitum 1명(3.8%), M. chelonae 1명(3.8%)의 순이었다. 균종에 따른 발병력은 M. intracellulare 67.9%(19/28명), M. abscessus 41.7%(5/12명)로 높았으며 M. fortuitum 14.3%(1/7명), M. chelonae 25%(1/4명)였다. NTM 폐질환 발생과 연관된 인자는 객담 도말양성(odds ratio=6.3, p=0.02), 분리된 균이 MAC 또는 M. abscessus인 경우(odds ratio=6.9, p=0.007)와 관련되어 있었다. NTM 폐질환 환자의 치료성공률은 57.7%(15/26명)이었으며 치료성공과 관련된 인자는 관찰할 수 없었다. 결 론 : 본원의 NTM이 분리된 환자 중 NTM 폐질환 비율은 높았으며 원인균에 있어서 MAC, M. abscessuss순이었다. 그리고 NTM 폐질환 발생과 연관된 인자는 객담 도말양성, 분리된 균이 MAC 또는 M. abscessus인 경우와 관련되어 있었다.