• Journal of Yeungnam Medical Science
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• 제6권2호
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• pp.195-205
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• 1989

암의 화학요법에 있어서 내성생성으로 인한 치료의 장애가 암 치료 실패의 중요 원인이 되며, 분 연구는 암세포의 항암제에 대한 내성 생성에 대한 특성을 연구 보고하였다. 사람의 위암 세포주 SNU-1에 대한 내성 유발을 위하여 세포배양액에 adriamycin(ADR) 농도를 $10^{-8}M$에서 $10^{-7}M$에 까지 적용시켜 내성세포주를 얻어 SUN-1/ADR로 나타내었으며 세포 성장은 SUN-1에서는 2일부터 6일까지 서서히 상승하였고 SNU-1/ADR은 $5{\times}10^3$celles/ml 농도 이상에서 상승을 보였다. 각 세포의 doubling 시간과 doubling 수를 비교하였으며 SNU-1은 doubling 시간이 평균 27.2 시간 doubling 수가 3.56번 이었으며, SNU-1/ADR은 52.2 시간 1.85번으로 내성세포가 더욱 성장이 왕성한 것을 관찰할 수 있다. MTT assay를 위하여 4일간의 성장으로 세포의 적절한 생존도를 관찰하였다. SNU-1과 내성세포주 SNU-1/ADR을 각각 항암제에 대한 약제 감수성 검사를 실시하였으며 약제농도 50%에서 생존도($IC_{50}$)를 비교하여 상관내성도(relative resistance : RR)을 측정 하였으며 vinblastine이 31.62이상으로 가장 높고, vincristine이 29.5, dactinomycin 21.37, epirubicin 17.78, daunorubicin 14.12였고, adriamycin 7.76이었으며 etoposide 4.46 이었다. 그 외의 약제 5-fluorouracil, cisplatin, cyclophosphamide, methotrexate, aclarubicin은 감수성이 낮았다. 위의 결과로 RR가 높은 약제들에 대해서는 multidrug resistance(복합내성)의 존재를 의미한다고 할 수 있으며 내성생성 SNU-1/ADR 세포주의 염색체의 검사에서 double minute chromosome(DMs)을 확인함으로서 내성 생성 세포를 확인 하였다.

• Tuberculosis and Respiratory Diseases
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• 제50권6호
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• pp.686-692
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• 2001

배 경 : 다제내성 폐결핵의 발생은 약제선택의 제한성과장기간의 항결핵제의 복용으로 인한 부작용 등으로 인하여 치료 성공율을 감소시킨다. 본 연구는 치료 실패인자들을 알아내어 다제내성 폐결핵의 치료 성공율을 향상시키는데 기초자료로 삼고자 하였다. 대상 및 방법 : 1996년 1월부터 1998년 12월까지 입원치료를 시행한 다제내성 폐결핵 환자 111명을 대상으로 하였다. 다제내성 폐결핵 치료의 실패에 관계되는 인자들을 분석하기 위하여 치료에 성공한 군(I군)과 실패한 군(II군)으로 나누어 각 인자들을 독립표본 T-검정, $X^2$ 검정 그리고 Fisher의 정확확률 검정으로 비교 분석하였다. 결 과 : I군과 II군을 비교한 결과, 폐결핵 과거력의 유무, 흉부방사선 검사상 공동이 있는 경우와 과거의 치료 횟수, 내성 약제의 개수 그리고 치료약제의 개수에서 통계적 유의성을 관찰할 수 있었다(p<0.05). 결 론 : 다제내성 폐결핵 치료 실패의 위험인자는 과거의 치료력, 흉부방사선상 공동이 있는 경우, 내성약제의 개수가 많은 것임을 알 수 있었다. 따라서 다제내성 폐결핵의 치료 효과를 향상시키기 위하여 초치료 폐결핵관리를 보다 철저히 하여 항결핵제에 대한 약제 내성발생을 억제하는데 노력을 하여야 할 것으로 생각된다.

• 생약학회지
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• 제47권2호
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• pp.122-127
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• 2016

Methicillin-Resistant Staphylococcus aureus(MRSA) is a multidrug-resistant(MDR) strain. (+)-Usnic acid(UA) is uniquely found in lichens, and is especially abundant in genera such as Usnea and Cladonia. UA has antimicrobial activity against human and plant pathogens. Therefore, UA may be a good antibacterial drug candidate for clinical development. In search of a natural products capable of inhibiting this multidrug-resistant bacteria, we have investigated the antimicrobial activity of UA against 17 different strains of the bacterium. In this study, the effects of a combination of UA and permeable agents against MRSA were investigated. For the measurement of cell wall permeability, UA with concentration of Ethylenediaminetetraacetic acid(EDTA) was used. In the other hand, Sodium azide($NaN_3$) was used as inhibitors of ATPase. Against the 17 strains, the minimum inhibitory concentrations(MICs) of UA were in the range of $7.81-31.25{\mu}g/ml$. EDTA or $NaN_3$ cooperation against MRSA showed synergistic activity on cell wall. UA and in combination with EDTA and $NaN_3$ could lead to the development of new combination antibiotics against MRSA infection.

• 대한임상검사과학회지
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• 제51권3호
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• pp.301-308
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• 2019

다제내성 P. aeruginosa의 출현과 확산은 전 세계적으로 중요한 문제가 되고 있다. P. aeruginosa에 의한 발병은 일부 몇몇 세포 관련 및 세포외 병독성 인자의 생성에 기인한다. 본 연구에서는 대전지역의 3차 병원에서 분리된 carbapenem 내성 P. aeruginosa를 대상으로 병독성 인자의 분포와 항균제 내성 양상을 조사하였다. 항균제 감수성 시험은 디스크 확산법으로 확인하였고, 병독성 유전자의 분석을 위해 PCR과 염기서열분석을 수행하였다. 또한, 다제내성 P. aeruginosa의 sequence type (ST)은 multilocus sequence typing (MLST)을 통해 확인하였다. 32균주의 carbapenem 내성 P. aeruginosa 중, 14균주(43.8%)가 다제내성이었으며, 주요 ST는 ST235 (10균주, 71.4.%)임을 확인하였다. 병독성 유전자는 32균주 모두에서 확인되었고, 이 중 가장 높은 빈도로 확인된 병독성 유전자는 toxA, plcN, phzM (100.%)이었다. 또한, 32균주는 모두 8개 이상의 병독성 유전자를 가지고 있었으며, 9균주(28.1%)가 15개의 병독성 유전자를 가지고 있었다. exoU 유전자는 다제내성 P. aeruginosa 균주의 71.4%에서 확인되었다. 이러한 결과는 exoU 유전자가 다제내성 P. aeruginosa 균주의 지속성에 대한 예측 표지자가 될 수 있을 것으로 사료된다.

• 한국환경보건학회지
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• 제50권2호
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• pp.93-101
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• 2024

Background: As pollutants caused by non-point sources flow into rivers, river water quality monitoring for fecal pollution is becoming increasingly important. Objectives: This study was conducted to investigate the distribution of microbial communities in the Yeongsangang River water system and sewage treatment plants in Gwangju and to evaluate their antibiotic resistance. Methods: In the experiment, samples were distributed to five selective media at each point and then cultured for 18 to 24 hours. When bacteria were observed, they were sub-cultured by size and shape and identified using MALDI-TOF MS equipment. When identification was completed, 17 types of antibiotic susceptibility tests were performed using VITEK II equipment, focusing on gram-negative dominant species among the identified strains. Results: During the study period, a total of 266 strains were isolated from 39 samples. Gram-positive bacteria were 37 strains in four genera, or 13.9% of the total, and Gram-negative bacteria were 229 strains in 23 genera, or 86.1% of the total. Antibiotic susceptibility testing of 23 strains, the major dominant species, showed that one strain (4.3%) was resistant to only one antibiotic, and two strains (8.7%) were 100% susceptible to the 17 antibiotics tested. The other 20 strains (87.0%) were multidrug resistant bacteria resistant to two or more antibiotics. There were various types of multidrug resistance. Among them, penicillin and cephalosporin series showed the highest resistance. Conclusions: Based on the results of this study, it was found that the bacterial community structure changed according to regional and environmental factors, and it was judged that continuous research such as genetic analysis of antibiotic-resistant bacteria present in natural rivers is necessary.

• Journal of Microbiology and Biotechnology
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• 제17권10호
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• pp.1733-1737
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• 2007

A total of 2,280 nonduplicate clinical isolates of Pseudomonas aeruginosa, obtained nationwide from Korean non-tertiary care hospitals from 2002 to 2005, were identified and their susceptibilities to aminoglycosides, antipseudomonal penicillins, carbapenems, cephalosporins, monobactams, and quinolones were studied, together with their production of ${\beta}$-lactamases. Using disk diffusion and minimum inhibitory concentration tests, it was found that 2.9% of isolates were multidrug-resistant (MDR) P. aeruginosa. An EDTA-disk synergy test, PCR amplification with specifically designed primers, and direct sequencing of the PCR products showed that the $bla_{OXA-10}$, $bla_{VIM-2}$, $bla_{OXA-2}$, $bla_{OXA-17}$, $bla_{PER-1}$, $bla_{SHV-12}$, and $bla_{IMP-1}$ genes were carried by 34.3%, 26.9%, 3.0%,3.0%, 1.5%, 1.5%, and 1.5% of 67 MDR P. aeruginosa isolates, respectively. The prevalence of MDR P. aeruginosa was three-fold higher, compared with that from the United States. More than two types of ${\beta}$-lactamase genes were carried by 10.4% of isolates. The most prevalent ${\beta}$-lactamase genes were $bla_{VIM-2}$ and $bla_{OXA-10}$. This study is the first description of MDR P. aeruginosa trom non-tertiary care hospitals in Korea and the coexistence of the $bla_{VIM-2}$, $bla_{IMP-1}$, or $bla_{PER-1} in these clinical isolates.

• Tuberculosis and Respiratory Diseases
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• 제60권3호
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• pp.353-356
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• 2006

폐결핵 치료중 흉부엑스선상 악화 및 갑자기 발생한 하지 마비와 감각이상으로 자기공명영상 촬영후 급성 횡단척수염 진단 및 객담 검사상 다제내성 결핵균 검출로 2차 결핵약제와 스테로이드 병합치료를 시행하여 부분적으로 호전을 보였던 증례이다. 급성 횡단척수염은 매우 드문 질환이며 균주의 직접 침범이나 면역학적 기전으로 발생하나 후자가 더 가능성 있는 기전으로 생각되어지고 있다. 아직도 결핵 및 다제내성 결핵의 유병률이 높은 국내 상황에서 드물게 결핵이 원인으로 추정된 급성 횡단척수염의 증례를 보고하는 바이다.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3309-3315
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• 2016

Helicobacter pylori as the second most common cause of gastric cancer in the world infects approximately half of the developed countries population and 80% of the population living in developing countries. Integrons as genetic reservoirs play major roles in dissemination of antimicrobial resistance genes. To the best of our knowledge, this is the first study to report carriage of class 1 and 2 integrons and associated gene cassettes in H. pylori isolates from Iran. This cross-sectional study was conducted in Tehran among 110 patients with H. pylori infection. Antimicrobial susceptibility testing (AST) for H. pylori strains were assessed by the micro broth dilution method. Class 1 and 2 integrons were detected using PCR. In order to determine gene cassettes, amplified fragments were subjected to DNA sequencing of both amplicon strands. The prevalence of resistance to clarithromycin, metronidazole, clarithromycin, tetracycline, amoxicillin, rifampin, and levofloxacin were 68.2% (n=75), 25.5% (n=28), 24.5% (n=27), 19.1% (n=21), 18.2% (n=20) and 16.4% (n=18), respectively. Frequency of multidrug resistance among H. pylori isolates was 12.7%. Class 2 integron was detected in 50 (45.5%) and class 1 integron in 10 (9.1%) H. pylori isolates. The most predominant gene cassette arrays in class 2 integron-bearing H. pylori were included sat-era-aadA1, dfrA1-sat2-aadA1, blaoxa2 and, aadB whereas common gene cassette arrays in class 1 integron were aadB-aadA1-cmlA6, aacA4, blaoxa2, and catB3. The high frequency of class 2 integron and multidrug resistance in the present study should be considered as a warning for clinicians that continuous surveillance is necessary to prevent the further spread of resistant isolates.

• 한국수산과학회지
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• 제47권3호
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• pp.220-226
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• 2014

Sixty-seven Vibrio parahaemolyticus isolates from surface seawater from the Wando area, on the southern coast of Korea, were analyzed for their susceptibility to 15 different antimicrobials and the presence of virulence genes. According to the disk diffusion susceptibility test, all of the strains studied were resistant to ampicillin and oxacillin, while decreasing percentages were resistant to vancomycin (64.2%), streptomycin (56.7%), amikacin (31.3%), kanamycin (22.3%), cephalothin (20.9%), erythromycin (10.4%), ciprofloxacin (4.5%), and tetracycline (3.0%). All of the strains were susceptible to five antimicrobials: chloramphenicol, gentamycin, nalidixic acid, sulfamethoxazole/trimethoprim, and trimethoprim. Fifty-nine isolates (88.1%) were resistant to three or more classes of antimicrobial and defined as multidrug resistant, and two strains were resistant to seven antimicrobial agents. The minimum inhibitory concentration (MIC) of the 67 V. parahaemolyticus isolates to ampicillin and oxacillin ranged from 512-2,048 and $64-512{\mu}g/mL$, respectively. All 67 isolates were also examined for the presence of the tdh and trh virulence genes using the polymerase chain reaction (PCR). However, no isolates possessed either tdh or trh. The VPA0477 (${\beta}$-lactamase) gene, present in all of the tested strains, was validated as a new specific marker gene in PCR assays for the accurate detection and identification of V. parahaemolyticus.

• 한국축산식품학회지
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• 제40권5호
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• pp.758-771
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• 2020

This study was to investigate the prevalence and characteristics of antimicrobial-resistant Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) from 4,264 retail meat samples including beef, pork, and chicken in Korea between 2013 and 2018. A broth microdilution antimicrobial susceptibility testing was performed for S. aureus. Molecular typing by multilocus sequence typing (MLST), spa typing, and pulsed-field gel electrophoresis (PFGE), was performed on mecA-positive S. aureus strain. S. aureus was isolated at a rate of 18.2% (777/4,264), of which MRSA comprised 0.7% (29 strains). MLST analysis showed that 11 out of the 29 MRSA isolates were predominantly sequence type (ST) 398 (37.9%). In addition, ST72, ST692, ST188, ST9, and ST630 were identified in the MRSA isolates. The spa typing results were classified into 11 types and showed a high correlation with MLST. The antimicrobial resistance assays revealed that MRSA showed 100% resistance to cefoxitin and penicillin. In addition, resistance to tetracycline (62.1%), clindamycin (55.2%), and erythromycin (55.2%) was relatively high; 27 of the 29 MRSA isolates exhibited multidrug resistance. PFGE analysis of the 18 strains excluding the 11 ST398 strains exhibited a maximum of 100% homology and a minimum of 64.0% homology. Among these, three pairs of isolates showed 100% homology in PFGE; these results were consistent with the MLST and spa typing results. Identification of MRSA at the final consumption stage has potential risks, suggesting that continuous monitoring of retail meat products is required.