국내 분리 폐렴 구균의 항균제 내성 현황 및 분자역학 조사를 통한 내성 전파의 규명

양지원,이남용,백경란,김성민,송재훈,배직현 대한감염학회 1996 감염 Vol.28 No.5

목 적 : 최근 폐렴구균의 항균제 내성은 전 세계적인 문제가 되고 있다. 국내에서도 폐렴구균의 페니실린 내성율이 70%를 넘어 세계 최고 수준의 내성을 나타내고 있다. 본 연구는 국내 분리 폐렴 구균의 페니실린 내성 및 다제 내성 현황을 확인하고, 국내의 내성율이 외국에 비하여 지나치게 높은 원인으로서 내성 전파의 가능성을 규명하고자 항균제 감수성 검사 및 pulsed-field gel electrophoresis(PFGE)와 penicillin-binding protein(PBP) profile을 분석하였다. 대상 및 방법 : 국내 2개의 3차 병원에서 1989년부터 1995년까지 153명의 환자 검체에서 분리된 173균주의 폐렴 구균을 대상으로 하였다. 항균제 감수성 검사는 oxacillin disk로 페니실린 내성 여부를 검색한 후, 한천희석법을 이용하여 11개 항균제의 성장억제최소농도를 구하였다. 항균제 감수성 검사 결과 모든 β-lactam 제제에 동시 내성을 보인 다제 내성 균주 42 균주를 대상으로 PFGE 와 PBP profile 분석을 시행하였다. PFGE는 SmaI과 ApaI을 제한효소로 사용하였으며, CHEF DR-Ⅱ system을 이용하여 전기영동하였다. PBP profile은 ³H-benzylpeniclillin으로 균주를 label하여 분석하였다. 결 과 : 항균제 감수성 결과 전체의 67.8%가 중등도 이상의 내성을 보였으며 (중등도 8.2%, 내성 59.6%), 3가지 종류 이상의 항균제에 동시 내성을 보이는 다제 내성율은 25.4%였다. 페니실린에 내성을 보이는 균주는 대부분 다른 항균제 특히 cephalosporin 제제에 내성을 보였다. 시험 균주의 혈청균은 19와 23이 가장 많았다. PFGE의 결과 35개의 다제 내성 균주 및 29 균주 (83%)가 동일한 제한 절편 양상을 보였으며, 총 5가지의 PFGE pattern 을 나타내었다. PBP profile 분석에서도 PFGE상 동일한 양상을 보인 다제내성 균주들은 PBP profile이 동일하였다. 결 론 : 본 연구는 기존의 국내 보고와 마찬가지로 폐렴구균의 페니실린 내성율이 세계 최고 수준임을 확인하였고, 아울러 다제 내성율도 현저히 증가하여 있음을 확인하였다. PFGE를 통한 유전자 절편 분석과 PBP의 변화 양상 분석을 통하여 다제 내성 균주의 80% 이상이 유전적 상관성이 있음을 확인함으로써, 내성의 전파가 국내에서 일어나고 있으며, 이 현상이 비교적 단기간에 국내에서 폐렴구균의 내성율을 급증하게 한 원인의 일부일 것으로 생각하였다. 향후 내성전파의 기전 및 근원에 대한 후속 연구가 내성 문제에 대한 장기적인 대책 마련에 필수적일 것으로 사료된다. Background : During recent three decades, the resistance of Streptococcus pneumoniae to penicillin has been rapidly increasing in many parts of the world. To characterize the epidemiology of multidrug-resistant S. pneunoniae as well as to investigate the possible spread of multiresistant clones which could partly explain the unusually high resistance rate in Korea, we conducted the antimicrobial susceptibility tests of pneumococcal isolates and performed pulsed-field gel electrophoresis (PFGE) and penicillin-binding protein (PBP) profile analysis of multiresistant strains from Korea. Methods : A total of 174 pneumococcal isolates obtained from 153 patients who visited or were admitted to two tertiary care hospitals during the period from 1989 to 1995 were studied. Antimicrobial susceptibility tests for 173 isolates were performed using agar dilution method to determine minimal inhibitory concentrations of 11 antimicrobial agents. A total of 42 isolates with multidrug-resistance were subjected to PFGE and PBP profile analysis to investigate the genetic relatedness between multiresistant strains, SmaI and ApaI were used to digest the genomic DNAs in PFGE. For PBP profile analysis, 5 mCi³H-benzylpenicillin were used to label PBPs of pneumococci. Results : Antimicrobial susceptibility tests for 173 isolates showed that 67.8% of isolates were not susceptible to penicillin, exhibiting either intermediate (8.2%) of resistance (59.6%). Multidrug-resistance to three or more classes of antibiotics was observed in 25.4% of the isolates. Almost all isolates with resistance to penicillin were resistant to cephalosporins. PFGE showed that 29 of 35 Korean isolates with multidrug-resistance had an identical PFGE pattern. These strains also shared a common PBP profiles with decreased affinity of PBPs 1a, 2x, and 2b. Conclusion : These data demonstrated the extremely high rates of penicillin- and multidrug-resistance in pneumococcal isolates in Korea. Molecular epidemiologic studies suggest the spread of a single epidemic clone of resistant pneumococci within Korea, which could partly explain the unusually high rate of resistance in Korea. Future investigation with regards to source and mode of transmission is warranted.

Ribotyping을 이용한 다제 내성 폐렴구균의 유전자 상관성 규명

김성민,송재훈,양지원,백경란,진정화,이남용,이혁 대한감염학회 1997 감염 Vol.29 No.6

목적:단기간에 급증하여 세계 최고를 기록하고 있는 우리나라의 폐렴구균 내성은 내성의 전파에 의할 가능성이 높다. 본 연구는 국내 및 미국, 스페인에서 분리된 다제 내성 폐렴구균의 유전적 상관성을 검증하여 내성의 전파 여부를 규명하기 위하여 ribotyping을 시행하였다. 방법:본 연구는 총 42균주의 다제 내성 균주(국내 분리 33주, 미국 4주, 스페인 5주)와 페니실린 감수성 R6 균주를 대상으로 하였으며, 모든 균주가 실제 감염증을 일으킨 침습성 균주였다. 한천희석법으로 항균제 감수성 검사를 하였으며, Quellung reaction을 이용하여 혈청형을 확인하였다. Ribotyping을 위하여 균주의 핵산을 분리한 후 Pvu Ⅱ로 절단하고 전기영동하였다. Ribotyping에 사용한 probe는 Escherichia coli의 16S+23S rRNS를 특이 primer로 역전사 중합효소 연쇄반응으로 증폭한 후 [α-??] dCTP로 labeling한 것을 이용하였다. Ribotype의 분석은 3 band 이상 차이가 나는 경우 다른 형으로 하였으며, 2 band까지의 차이는 아형으로 간주하였다. Hunter와 Gaston의 방법을 이용하여 discriminatory index(ID value)을 계산하였으며, Dice coefficient를 이용하여 dendrogram을 구성하였다. 결과:다제 내성 폐렴구균의 ribotype은 총 12개의 pattern으로 구분되었으며, A 혹은 A subtype으로 분류된 것이 한국 균주 19주(57.6%), 미국 3 균주(75%), 스페인 4 균주(80%)였다. Ribotyping의 ID value는 0.83이었다. 결론:Ribotyping의 결과 국내 다제 내성 균주의 57.6%가 동일한 ribotype을 보유하고 있음은 기존의 분자 역학 연구의 결과와 마차가지로 국내에 존재하는 내성 균주가 유전적 상관성을 가지고 있음을 의미하는것이다. 이는 내성의 전파가 국내의 내성율을 단기간에 급증시키는 원인으로 작용하였을 가능성을 뒷받침한다. 동시에 외국 균주와도 유전적 상관성이 있어 국가 간 전파도 가능함을 알려 주고 있다. Background: Recent data from Korea showed that penicillin-resistance in pneumococci was more than 70% with 35% of multidrug-resistance(MDR) among invasive isolates. One of the most important reasons for the rapid increase of pneumococcal resistance in Korea would be the spread of resistance. Previous data of pulsed-field gel electrophoresis(PFGE) and penicillin-binding protein profile suggested the spread of pneumococcal resistance. To investigate the genetic relatedness of multidrug-resistant strains, we performed the ribotyping with resistant strains isolated from different countries. Methods: A total of 42 pneumococcal isolated from Korea(33), Spain(5), and the United States(4), which were resistant to more than 3 classes of antimicrobial agents on agar dilution methods, and a R6 penicillin-susceptible strain were used for ribotyping. Ribotyping was performed with the restriction enzyme Pvu Ⅱ by using a [α-??]dCTP-labeled gene probe from Escherichia coil 16S+23S RNA. Results: Ribotype of a R6 strain was quite different form those of resistant strains. A total of 12 different ribotypes were noted in multidrug-resistant strains. Nineteen of 33 Korean strain(57.6%), 3 strains from the United States(75%), and 4 strains form Spain(80%) belonged to ribotype A or A subtypes. Discriminatory index of the ribotyping was 0.83. Ribotyping produced more patterns which could denote more discriminatory power than PFGE. Conclusion: The data strongly suggest the genetic relatedness of resistant strains from different countries. It might suggest the spread of pneumococcal resistance within Korea which could partly explain the rapid increase of resistance in a short period.

Conditional probability analysis of multidrug resistance in Gram-negative bacilli isolated from tertiary medical institutions in South Korea during 1999–2009

김용학 한국미생물학회 2016 The journal of microbiology Vol.54 No.1

Multidrug resistance of Gram-negative bacilli is a major problem globally. However, little is known about the combined probability of resistance to various antibiotics. In this study, minimum inhibitory concentrations of widely used antibiotics were determined using clinical isolates of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii, randomly chosen from strain collections created during 1999–2009 in tertiary medical institutions in Seoul, South Korea. To analyze combined efficacy of antibiotics against a subgroup of isolates, conditional probabilities were determined based on arbitrary, non-independent patterns of antimicrobial susceptibility and resistance. Multidrug resistance, defined as resistance to three or more classes of antibiotics, was observed in the following order: A. baumannii (96%), P. aeruginosa (65%), E. coli (52%), and K. pneumoniae (7%). A. baumannii strains resistant to gentamicin were found to be resistant to a number of antibiotics, except for colistin and polymyxin B. Resistance to gentamicin following exposure to this antibiotic was highly likely to lead to multidrug resistance in all four microbes. This study shows a causal relationship between gentamicin resistance and the prevalence of multidrug resistance in clinical isolates of Gramnegative bacilli in South Korea during 1999–2009 and suggests the importance of prudent use of gentamicin in hospitals.

H₂O₂ Generating Ability and Multi-Drug Resistance of Lactic Acid Bacteria Required for Long-Term Inpatient Treatment with Antibiotic Resistance

육영삼 한국인터넷방송통신학회 2022 International journal of advanced smart convergenc Vol.11 No.4

Purpose: In our study, in order to find lactic acid bacteria (LAB) with multi-drug resistance to antibiotics, we isolated 140 strains from 15 types of kimchi commercially available in Korea and 20 types of Kimchi made at home from January to December in 2016, and investigated their H₂O₂ generating ability and multidrug resistance to antibiotics. Methods: In order to observe the H₂O₂ generation ability of LAB, we performed the experiment with methods such as Rabe, Hillier, and Kang. To test the antibacterial susceptibility of LAB, we used the disc agar diffusion method using MRS agar (Difco, USA) according to the CLSI and WHO test methods. There are 18 types of antibiotic discs used. Results: Out of the total numbers of 140 strains, 6 strains of Ent. Faecium, 25 strains of L. plantarum, 1 strain of L. rhamnosus, 3 strains of L. sakei, 1 strain of L. acidophilus, 1 strains St. thermophilus, and 7 of unidentified strains generated H₂O₂ . The antibiotic susceptibility of Ent. Faecium indicated SXT, OX, NA, and E; and the antibiotic susceptibility of L. plantarum indicated NA; and the antibiotic susceptibility of St. thermophilus indicated NA, CC, RA, CTT, CM, and P ; and the antibiotic susceptibility of L. rhamnosus indicated SXT, VA, NA and CTT; and the antibiotic susceptibility of 6 strains of L. sakei indicated SXT, OX, NOR, NA, CTT and CIP, all indicating antibiotic resistance. In the case of multi-drug resistance to antibiotics for 53 strains of L. antarum, 8-drug resistance was the most common with 25 strains, followed by 7-drug-resistant strains with 18 strains, 9-drug-resistant strains with 4 strains, 6-drug-resistant strains with 3 strains, 5-drug-resistant strains with 2 strains, and 17-drug-resistant strains with 1 strain. In the case of multi-drug resistance to antibiotics for Ent. Faecium 27 strains, 9-drug resistance was most commonly identified as 9 strains, 8-drug resistance was identified as 6 strains, 7- and 11 drug resistances were identified as 4 strains each, and 4- and 6-drug resistances were identified as 1 strain each. Conclusion: Ent. Faecium, L. plantarum, L. rhamnosus, L. sakei, and St. thermophilus, shown to have anantibacterial activity in previous studies on LAB and shown to have and H₂O₂ generating ability, antibiotic resistance and multi-drug resistance in this study, are expected to be able to play an excellent role for long-term inpatients to use as an alternative to antibiotics and to cope with emerging antibiotic resistance.

서해안 패류양식장 인근 육상오염원에서 분리한 장구균의 Vancomycin 내성 유전자 검출 및 항생제 내성 특성

정연겸,박보미,황진익,김민주,오은경 한국수산과학회 2022 한국수산과학회지 Vol.55 No.5

In this study, 143 strains of Enterococcus spp. were isolated from inland pollution sources near shellfish farms on the west coast of South Korea. Not all isolated Enterococcus spp. strains possessed vancomycin resistance genes (VanA and VanB). However, since vancomycin-resistance Enterococcus (VRE) have been detected not only in the clinical field but also out in the world, it is possible that the VRE gene may be transferred to other bacterial strains commonly found in coastal waters where seafood is produced. It is important to monitor trends in the appearance of VRE. In addition, antimicrobial resistance patterns of isolates were examined in this study. Overall antimicrobial resistance rates were high: ciprofloxacin (32.2% of isolates resistant), chloramphenicol (30.8%), quinupristin/dalfopristin (19.6%), and tylosin (15.4%). Eight E. faecium strains (6.2%), out of the 129 strains assessed, showed multidrug resistance. All multidrug-resistant E. faecium showed resistance to erythromycin, quinupristin/dalfopristin, tetracycline, and tylosin, in all 14 strains. All multidrug-resistant E. faecalis showed resistance to erythromycin, quinupristin/dalfopristin, tetracycline, and tylosin. Both multidrug-resistant E. faecium and multidrug-resistant E. faecalis showed common resistance to erythromycin, quinupristin/dalfopristin, tetracycline, and tylosin.

다제내성균의 표본감시 및 분자역학 특성

이영선,김화수,유정식,유재일,정영희 대한임상미생물학회 2012 Annals of clinical microbiology Vol.15 No.2

The global emergence and spread of multidrug resistant bacterial infections in communities and hospitals has become an important issue in public health. The resistance rate of gram-positive cocci to vancomycin and the resistance rate of several gram-negative bacilli against cefotaxime and carbapenem have been continuously increasing. Surveillance of antimicrobial resistance is essential for providing information on the magnitude of and trend in multidrug resistance. Therefore, beginning 2011, more robust and effective management is to be legally required for six multidrug-resistant bacteria that have been linked to healthcare-related infections: vancomycin-resistant Staphylococcus aureus (VRSA), vancomycinresistant enterococci (VRE), methicillin- resistant S. aureus (MRSA), multidrug-resistant Pseudomonas aeruginosa (MRPA), multidrug-resistant Acinetobacter baumannii (MRAB), and carbapenem-resistant Enterobactericeae (CRE). We have also performed laboratory-based sentinel surveillance for VRSA/VISA since 2002 and carbapenemase-producing Enterobacteriaceae since November, 2010. This article reviews the national surveillance programs, and molecular epidemiology of multidrug-resistant bacteria.

Bacillus subtilis from Soybean Food Shows Antimicrobial Activity for Multidrug-Resistant Acinetobacter baumannii by Affecting the adeS Gene^s

( Tieshan Wang ),( Jianrong Su ) 한국미생물 · 생명공학회 2016 Journal of microbiology and biotechnology Vol.26 No.12

Exploring novel antibiotics is necessary for multidrug-resistant pathogenic bacteria. Because the probiotics in soybean food have antimicrobial activities, we investigated their effects on multidrug-resistant Acinetobacter baumannii. Nineteen multidrug-resistant A. baumannii strains were clinically isolated as an experimental group and 11 multidrug-sensitive strains as controls. The growth rates of all bacteria were determined by using the analysis for xCELLigence Real-Time Cell. The combination of antibiotics showed synergistic effects on the strains in the control group but no effect on the strains in the experimental group. Efflux pump gene adeS was absent in all the strains from the control group, whereas it exists in all the strains from the experimental group. Furthermore, all the strains lost multidrug resistance when an adeS inhibitor was used. One strain of probiotics isolated from soybean food showed high antimicrobial activity for multidrug-resistant A. baumannii. The isolated strain belongs to Bacillus subtilis according to 16S RNA analysis. Furthermore, E. coli showed multidrug resistance when it was transformed with the adeS gene from A. baumannii whereas the resistant bacteria could be inhibited completely by isolated Bacillus subtilis. Thus, probiotics from soybean food provide potential antibiotics against multidrug-resistant pathogenic bacteria.

다제 내성 폐결핵 환자의 임상상 및 치료에 대한 고찰

이재철,이승준,김계수,유철규,정희순,김영환,한성구,심영수,Lee, Jae-Cheol,Lee, Seung-Jun,Kim, Gye-Soo,Yoo, Chul-Gyu,Cheong, Hee-Soon,Kim, Young-Whan,Han, Sung-Koo,Shim, Young-Soo 대한결핵및호흡기학회 1996 Tuberculosis and Respiratory Diseases Vol.43 No.1

연구배경: 다제 내성 폐결핵 환자의 임상적 특성과 약제별 내성률, 치료에 영향을 미치는 인자, 이차 약제로 인한부작용, 치료내용 및 차료성적 등을 살펴 보고자 하였다. 대상: 약제 감수성 검사상 두가지 이상의 일차 약제에 동시 내성을 보이는 환자를 대상으로 후향성 연구를 시행하였다. 치료 결과의 판정은 정기적으로 6개월 이상 추적 관찰이 가능했던 환자만을 대상으로 치료후 호전을 1개월 이상의 간격으로 시행한 가래 검사상 3회 이상 음성이고 방사선 소견이 호전되거나 6개월 이상 변화가 없는 경우로, 치료 실패를 6개월간의 치료에도 균 음전화가 되지 않거나 방사선 소견상 악화를 보이는 경우로 정의하였다. 대상 환자들은 감수성 검사 결과에 따라 감수성 약제를 4제 이상 투여하여 치료받았다. 결과: 1) 총 71예와 환자를 대상으로 조사한 결과 35예(49%)에서 방사선상 공동을 관찰할 수 있었고 평균 4.1개의 약물에 내성을 지니고 있었는데 90%가 INH, RFP 동시 내성을 보였다. 2) 치료 결과의 판정이 가능하였던 55예중 35예(67%)의 환자가 치료후 호전을 보였으며 치료 실패는 18예(33%)이었다. 일차 내성 환자가 5예이었는데 치료 결과 판정이 가능하였던 4예는 모두 치료에 성공하였다. 3) 약제 부작용은 14예(20%)에서 나타났는데 간기능 악화가 6예로 가장 많았고 어지러움증 5예, 고요산 혈증을 동반한 관절통이 3예, 이명 3예 등의 순이었다. 이들 부작용의 절반 이상이 투약후 3개월 이내에 발생 하였다. 4) 약제 감수성 검사를 반복했을 때 INH, RFP의 경우 100% 가까운 일치율을 보였고 EMB, PZA 80% 정도 나머지 약물은 50% 미만이었다. 5) 5예의 환자가 수출을 받았고 이 중 1예는 항결핵 화학 요법의 보조적 치료로 수술을 했는데 균 음전화에 성공하였다. 결론: 다제 내성 폐결핵 환자에서도 규칙적인 약물 복용과 적절한 처방으로 약 2/3 정도에서 호전이 관찰되어 적극적인 항결핵 화학 요법을 시행해야 할 것으로 생각되지만 치료와 예후 판정에 도움이 되는 인자를 찾지는 못하였다. Objectives: Although outbreak of MDR Tb has been a recent problem in western countries, it has been a longstanding problem in Korea. The poor outcome of MDR Tb is mainly due to poor compliance, high rate of side reaction of secondary drugs, and limitation in number of available drugs. Thus, to improve the outcome of MDR Tb, it is crucial to make individualized adequate prescription based on the knowledge of the patterns of resistance to each drugs in the community as well as the natural history. The purpose of present study is to evaluate the clinical features of Korean MDR Tb patients including patterns of drug resistance and success rate of treatment which was prescribed according to the sensitivity tests. Methods: Retroscpective analysis of 71 Korean patients with MDR Tb was made. All strains isolated from patients showed resistence to at least two first line drugs. Patients profile, previous treatment history, patterns of drug resistance, outcome of treatment was analysed. Initial treatment regimen was selected according to the previous treatment history and was modified according to the sensitivity reports. The regimen was composed to include at least 4 sensitive drugs when possible. Results: The patients showed resistance to 4.1 drugs on average. 90% of them were resistant to INH and RFP. Among 71 patients, 35 patients(49%) had cavitary lesions in CXR. Treatment outcome was analysed in 55 patients. 35 patients(67%) were improved after treatment and 18 patients(33%) showed treatment failure. 5 patients showed primary resistance. Treatment outcome could be evaluated in 4 of them and all showed improvement after treatment. 14 patients(20%) had to change their regimens due to drug side effects. The most frequent side effect was elevation of liver enzymes(6 patients). Others included dizziness, hyperuricemia, tinnitus, skin rash, GI troubles. More than 50% of side effects developed within 3 months. In repeated drug sensitivity test, the concordance rate of resistance to INH was 100% and RFP 98%. EMB, PZA showed 80% concordance rate. But in the other drugs, the concordances were less than 50%. Operation was done in 5 patient - 1 patients as a adjunctive means of chemotherapy -. In that case, negative conversion of sputum AFB was done. Conclusion: 2/3 patients of multidrug-resistant tuberculosis were improved by appropriate prescription and regular medication suggesting that more aggressive management and monitoring is indicated in multidrug-resistant tuberculosis.

Lack of association between C3435T nucleotide MDR1 genetic polymorphism and multidrug-resistant epilepsy

Kim, Dong Wook,Kim, Manho,Lee, Sang Kun,Kang, Rami,Lee, Seo-Young Elsevier 2006 SEIZURE Vol.15 No.5

<P><B>Summary</B></P><P>The variability of P-glycoprotein expression in individuals is linked to a C3435T polymorphism of the multidrug-resistance 1 (MDR1) gene, and the CC genotype at the C3435T polymorphism was reported to be associated with multidrug resistance in epilepsy patients. Since population frequencies of polymorphic genes depend on ethnic specificity, we investigated functional significance of the C3435T polymorphism of the MDR1 gene in Korean epilepsy patients. One hundred and eight patients with drug-responsive epilepsy, 63 patients with drug-resistant epilepsy, and 219 control migraine subjects were studied, but the analysis for C3435T allele showed no significant association between the CC genotype and the multidrug-resistant epilepsy. We suggest that influence of the C3435T polymorphism in the multidrug-resistant epilepsy may not be significant in Korean populations and further investigations in various ethnic populations would be necessary to clarify the effect of C3435T polymorphism on the mutidrug resistance in epilepsy patients.</P>

Cispatin 내성인 사람 위암 세포주 SNU-1의 복합약제내성 및 Verapamil의 효과

손성권,김정희 영남대학교 의과대학 1992 Yeungnam University Journal of Medicine Vol.9 No.1

복합약제내성 암세포주의 출현은 암의 화학요법에 있어서 중요한 문제점중의 하나이며 이 복합내성 암세포의 출현에 대한 정확한 기전은 아직 밝혀져 있지 않다. 본 실험에서는 약제내성 암세포의 다른 항암제에 대한 복합내성 형성정도와 calcium 길항제인 verapamil에 의한 내성극복 정도를 비교하고 내성 암세포의 세포막 단백질의 변화를 관찰하였다. 사람의 위암 세포주 SNU-1을 cisplatin농도 0.001μM까지 증가시켜 내성세표 ??를 얻었으며, MTT assay로 세포성장을 관찰한 결과 doubling time은 SNU-1이 약 29시간, ??는 약 38시간으로 내성세포가 감수성세포보다 성장속도가 느린 것을 관찰하였다. 약제 감수성 검사를 위해서 4일간의 MTT assay로 대조군에 대한 50% 세포 생존시의 약제농도 ??를 비교하여 상대적 내성도(Relative Resistance, RR)를 측정하였는데 cisplatin, 81.4; vinblastine, > 43.0; epirubicin, 22.9; dactinomycin, 16.0: etoposide, 15.0; vincristine, 9.2; adriamycin, 5.7; aclarubicin, 5.3으로 관찰되었고 그외의 약제인 cyclophosphamide, 5-fluorouracil, methotrexate, daunorubicin에서는 낮게 나타났다. 10μM의 verapamil에 의한 내성억제 효과는 vincristime, 13.1; epirubicin, 10.0; etoposide, 6.3; vinblastine, 4.4; dactinomycin, 3.6; daunorubicin, 2.4로 나타났다. Radioiodination을 이용한 SDS-PAGE로 SNU-1/Cis5에서 항암제 내성과 관련된 것으로 여겨지는 51,400와 81,300 dalton의 막단백질의 발현을 관찰하였다. The development of multidrug-resistant tumor cell population is a major problem in the chemotherapy of human cancer. These cells are often cross resistant to unrelated drugs and the precise mechanisms of multidrug resistant phenotype of tumor cells has not been fully elucidated. Cisplatin resistant tumor cell(SNU-1/Cis5) was induced from human stomach cancer cell line (SNU-I) in vitro. Growth profiles of survival cells were observed during 5 days by thiazolyl blue (MTT) assay. To investigate the cross resistance of various anticancer drugs in SNU-1 and ??, We compared the value of ??-drug concentration at 50% survival of control and gained relative resistances (RR). The RR for ?? were as follows. vinblastine, >43.0; epirubicin, 22.9; dactinomycin, 16.0 ; etoposide, 15.0; vincristine. 9.2 ; adriamycin, 5.7; aclarubicin, 5.3. But 5-fluorouracil, methotrexate, daunorubicin have not cross resistance with cisplatin. Resistant inhibition values of 10μM verapamil for ?? were as follows ; vincristine, 13.1 ; epirubicin, 10.0; etoposide, 6.3; vinblastine, 4.4; dactinomycin, 3.6; daunorubicin, 2.4. Membrane proteins of 51,400 and 81,300 daltons were identified by radioiodination with SDS-PAGE, which might represented the drug resistance.