• Tuberculosis and Respiratory Diseases
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• v.38 no.2
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• pp.99-107
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• 1991

Drug resistance of M. tuberculosis has been investigated with isolates from patients screened out of the sample population of the nationwide tuberculosis prevalence surveys or from the routine cultures. The results showed a close inverse relationship between prevalence of drug resistance and efficiency of the past or current treatment regimens of NTP. Individual drug resistance also showed a close relationship with the extent of use of the relevant drugs. Drug resistance was found in 38.0% of M. tuberculosis isolates from patients found in 1965 survey and remained unchanged until it increased upto 48.0% in 1980 survey. The resistance prevalence, however, dropped to 30.8% in 1985 and further to 25.3% in 1990 survey. Such decrease was fairly well coincided with a continuous increase of the treatment efficiency (from 60% in 1984 to 77% in 1989) in 1980s. Initial drug resistance also showed a similar trend, namely 26.2% in 1965, 23.9% in 1970, 20.1% in 1975, 30.6% in 1980, 17.4% in 1985, and 15.0% in 1990. The similar figures were observed in M. tuberculosis isolates from patients diagnosed in the routine services. Higher prevalence of initial drug resistance was observed among urban patients than rural patients and among young patients than old patients. These findings signify that a continuous survey on drug resistance permits to monitor efficiency of treatment programme of the country.

• Tuberculosis and Respiratory Diseases
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• v.64 no.2
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• pp.87-94
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• 2008

Background: Surveillance of TB drug resistance (DR) is essential for providing information on the magnitude and trends in resistance, for developing treatment guidelines and for monitoring the effect of interventions. Up to now national surveys of drug resistance of M. tuberculosis have been conducted four times since 1994 among patients registered at health centers. The purpose of this study is to estimate the prevalence of primary drug resistance among new cases identified in private sector, and to compare it with the previous national drug resistance surveys. Methods: The study collected results of drug susceptibility testing (DST) performed at the Korean Institute of Tuberculosis by the request of private sector from January 2003 to December 2005, and then finally selected new cases for the analysis from the database of Korean TB Surveillance (KTBS) by matching patients' name and social identification numbers. Results: Of the 5,132 new patients included in the study, 689 (13.4%) patients were found to have drug resistance at least one drug, 530 patients (10.3%) were isoniazid resistant, 195 patients (3.8%) were multi-drug resistant (MDR), and 21 patients (0.4%) were extensively drug resistant (XDR). The rate of drug resistance tended to decrease annually but it was not statistically significant. When compared with previous national DR surveys in 2003 and in 2004 respectively, they were not significantly different. Conclusion: The prevalence of DR among new cases managed in the private sector did not show significant difference from that of new patients registered in the public sector in the same year.

• Tuberculosis and Respiratory Diseases
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• v.55 no.1
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• pp.41-58
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• 2003

Background : The resurgence of tuberculosis and the widespread emergence of multidrug-resistant M. tuberculosis have emphasized the importance of rapid and accurate diagnostic procedures. Recently, the oligonucleotide chip has proven to be a useful tool in the rapid diagnosis of infectious diseases. The purpose of this study was to rapidly and accurately detect specific mutations in the rpoB, katG and rpsL genes associated with rifampin, isoniazid and streptomycin resistance in M. tuberculosis, respectively, using a single oligonucleotide chip. Method : For detection of drug-resistance, 7 wild-type and 13 mutant-type probes for rifampin, 2 wild-type and 3 mutant-type probes for isoniazid, and 2 wild-type and 2 mutant-type probes for streptomycin were designed and spotted onto glass slides. Fifty-five cultured samples of M. tuberculosis were amplified by PCR, and then underwent hybridization and scanning. Direct sequencing was done to verify the results from the oligonucleotide chip and to analyze the types of mutations. Result : Thirty-five cases out of 40 rifampin-resistant strains(~88%) had mutations in the rpoB gene. One case had a new mutation(D516F, GAC R TTC) and another known mutation together. Twenty cases out of 42 isoniazid-resistant strains(~50%) had mutations in the katG gene, while 7 cases out of 9 streptomycin-resistant strains(~78%) had mutations in the rpsL gene. From these results, the oligonucleotide chip was confirmed to be able to detect the most frequent mutations from the genes associated with rifampin, isoniazid and streptomycin resistance. The results proved that the drug-resistance detection probes were specific. When the results from the oligonucleotide chip and DNA sequencing were compared, the types of mutations were exactly matched. Conclusion : The diagnostic oligonucleotide chip with mutation specific probes for drug resistance is a very reliable and useful tool for the rapid and accurate diagnosis of drug resistance against rifampin, isoniazid and streptomycin in M. tuberculosis infections.

• Korean journal of applied entomology
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• v.42 no.3
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• pp.225-231
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• 2003

The susceptibility of the different larval stages of Spodoptera litura to nine insecticides was evaluated using the perilla leaf-dipping method. Median lethal concentration ($LC_{50}$) was increased with larval development in the range of 0.5 ppm to 5.6 ppm, 9.9 ppm to 27.9 ppm, 9.6 ppm to 125.1 ppm and 24.3 ppm to 546.6 ppm in the 1st, 2nd, 3rd and 4th instar, respectively. The tolerance ratio (TR), which is the TR of 90 percent lethal concentration (LC/ sub 90/) to the recommended concentration, was 0.04 to 0.8 in the 1 st, 0.2 to 7.5 in the 2nd, 0.7 to 115.3 in the 3rd and 1.2 to 485.4 in the 4th instars. Lower D$LC_{50}$ and DTR, which is the difference between the $LC_{50}$ and the TR of 4th and other instars, respectively, were observed in chlorfenapyr, chlorpyrifos and EPN while higher ones were lufenuron, chlorfluazuron and teflubenzuron. These results mean that insecticides with lower D$LC_{50}$ and DTR are effective in controlling larva of S. litura collected in Milyang, Korea.

• Korean Journal of Microbiology
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• v.49 no.1
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• pp.90-94
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• 2013

A new Bacillus strain designated as MP56 producing antimicrobial substance has been isolated from the mud flat of Korea. The strain MP56 was found to exhibit broad spectrum of antimicrobial activity against Gram-positive pathogenic microorganisms and MDR (multi drug resistant) strains. The 16S rRNA sequence revealed that the MP56 was closely related to Bacillus subtilis with 99.93% homology. The optimal medium composition for production of antimicrobial substance in the B. subtilis MP56 were 1% mannitol, 1% oat meal, 0.01% $CaCl_2$. Antimicrobial activity of the culture broth against different pathogenic strains was assessed using the antimicrobial spectrum. The result suggests that Bacillus strain MP56 produces high quality antimicrobial substance that might be very useful to control varieties of pathogenic microbial growth.

• Korean Journal of Veterinary Research
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• v.26 no.2
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• pp.229-235
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• 1986

1984년 5월부터 1985년 5월까지 대구(大邱), 경북(慶北), 경남(慶南) 및 충남지역(忠南地域) 7개(個) 양돈장(養豚場)의 자돈(仔豚) 및 성돈(成豚)의 분변(糞便) 및 양돈장(養豚場)의 흙, 하수(下水), 사료(飼料), 추비(推肥), 쥐 등 7,440예(例)와 대구시(大邱市) 도축장(屠畜場)의 도축돈(屠畜豚) 장간막임파절(腸間膜淋巴節) 및 직장내용물(直腸內容物) 555예(例)로부터 분리(分離)한 319주(株)의 Salmonelia속균(屬菌)을 대상으로 항균제(抗菌劑)에 대한 내성(耐性) 및 전달성(傳達性) R plasmid의 분포상황(分布狀況)을 조사(詞査)하였던 바 그 결과(結果)는 다음과 같다. 1. 공시균(供試菌) 319주(株) 중(中) 250주(株)(78.4%)가 ampicillin(An), chloramphenicol(Cm), gentamicin(Gm), kanamycin(Km), nalidixic acid(Na), rifampicin(Rf), streptomycin(Sm), sulfadimethoxine(Su), 또는 tetracycline(Tc)에 내성(耐性)을 나타내었으며, 약제별(藥劑別)로는 Su(74.9%), Sm(53.0%) 및 Tc(28.5%)에 높은 내성(耐性)이 인정(認定)되었다. 2. 내성균(耐性菌) 250주(株)의 전달성(傳達性) R plasmid 보유율(保有率)은 51.2%(128주(株))였으며, 약제별(藥劑別)로는 Am경우 100%, Tc 92. 3% 및 Cm 75.0% 순으로 보유율(保有率)이 높았다. 3. 내성균(耐性菌) 250주(株)의 내성양상(耐性樣相)은 SmSu(91주(株)), Su(59주(株)) 및 TcSmSu(50주(株))내성형(耐性型)이 대부분이었고 R plasmid 전달후(傳達後)의 내성양상(耐性樣相)은 TcSmSu(40주(株)) 및 TcSu(28주(株)) 내성형(耐性型)이 많았다. 4. 양돈장별(養豚場別) 내성균(耐性菌) 출현빈도(出現頻度)는 48.0~93.6%로 다양(多樣)하였고, 전달성(傳達性) R plasmid 보유율(保有率)은 0~77.8%로 내성균(耐性菌) 출현빈도(出現頻度)와 일치(一致)되지 않았다. 5. 공시균(供試菌) 319주(株) 중(中) 각각(各各) 2주(株)는 Rf 및 Gm에 대해 내성(耐性)을 나타내었고, 내성균(耐性菌) 250주(株) 중(中) 73.2%(183주(株))가 다제내성(多劑耐性)이었으므로 Salmonella의 다제내성화(多劑耐性化) 경향(傾向)이 있었다. 6. 내성균(耐性菌) 250주(株) 중(中) R plasmid 전달후(傳達後) 5주(株)는 TcAmCmSmSu내성형(耐性型), 1주(株)는 TcAmKmSmSu내성형(耐性型)임이 확인되었다.

• 보건세계
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• v.44 no.8 s.492
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• pp.4-6
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• 1997

근래 조형균(Mycobacterium avium complex : MAC)에 의한 항산균증과 일부 약제내성 결핵의 치료제로 알려지고 있는 리파부틴(rifabutin, RBT), 간헐치료제로써 연구가 되고있는 리파펜틴(rifapentine, RPT)에 대하여, 결핵환자와 치료 처방을 결정하는 의사들의 정확한 이해를 돕기 위해 이 약제들에 대한 간단한 소개를 하고자 한다.

• Korean Journal of Poultry Science
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• v.19 no.3
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• pp.151-160
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• 1992

Control of coccidiosis depends on medication, management, immunity, or some combination of these methods. Prophylactic medication with anticoccidials remains the primary method of control, although the development of drug resistance is a major problem. Shuttle and rotation programs are increasingly used to delay the onset of drug resistance. Sensitivity testing has become an important tool in the identification of what specific medications will be effective in specific poultry operations. Management techniques for the control of coccidiosis have not been totally effective because most disinfectants do not kill the coccidial oocysts. Present methods for vaccination are currently limited to the use of controlled doses of live coccidia. New vaccination methods under investigation include vaccination with attenuated strains or parasite antigens produced either by fractionating the parasites or genetically engineered sub unit vaccines.

• Journal of Yeungnam Medical Science
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• v.6 no.2
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• pp.195-205
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• 1989

Development of drug resistance in tumors during treatment is a major factor limiting the clinical use of anticancer agents. When tumor cells acquire resistance to anticancer drug, they show cross-resistance to other antitumor agents. In the present study, SNU-1 cell was induced adriamycin $10^{-7}M$ drug resistance, SNU-1/ADR, in vitro culture system. We got the doubling time and number for viability test during 96 hours by MTT assay. To investigate the cross resistance of various anticancer drugs in human stomach cancer cell SNU-1 and SNU-1/ADR. We compared $IC_{50}$ (drug concentration of 50% reduction) and the relative resistance(RR). SNU-1/ADR was expressed multidrug resistant with vinblastine(RR ; 31.62), vincristine(RR ; 29.50), dactinomycin(RR ; 21.37), epirubicin(RR ; 17.78), daunorubicin(RR ; 14.12), adriamycin(RR ; 7.76), and etoposide(RR ; 4.46), and other drugs, 5-fluorouracil, cisplatin, cyclophosphamide, methotrexate, and aclarubicin, have not cross resistant with adriamycin. There was double minute chromosome in SNU-1/ADR by karyotyping although this change was not seen in SNU-1.

• Tuberculosis and Respiratory Diseases
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• v.66 no.3
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• pp.198-204
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• 2009

Background: First-line drugs, if sensitive, are the most potent drugs in the treatment of multidrug-resistant tuberculosis (MDR-TB). This study examined the frequency and risk factors associated with acquired drug resistance to first-line drugs during a standardized treatment using first-line drugs in patients with MDR-TB. Methods: This study included patients who were diagnosed with MDR-TB at the National Masan Tuberculosis Hospital between January 2004 and May 2008, treated with standardized first-line drugs, and for whom the preand post-treatment results of the drug susceptibility test were available. Their medical records were reviewed retrospectively. Results: Of 41 MDR-TB patients, 14 (34.1%) acquired additional resistance to ethambutol (EMB) or pyrazinamide (PZA). Of 11 patients initially resistant to isoniazid (INH) and rifampicin (RFP), 3 (27.3%) acquired additional resistance to both EMB and PZA, and 3 (27.3%) to PZA. Of 18 patients initially resistant to INH, RFP and EMB, 6 (33.3%) acquired additional resistance to PZA. Of 6 patients initially resistant to INH, RFP and PZA, 2 (33.3%) acquired additional resistance to EMB. Ten of the 41 MDR-TB patients (24.4%) changed from resistant to susceptible. No statistically significant risk factors associated with acquired resistance could be found. Conclusion: First-line drugs should be used cautiously in the treatment of MDR-TB in Korea considering the potential acquisition of drug resistance.