• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1216-1225
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• 2014

Biofilm-related infections of Candida albicans are a frequent cause of morbidity and mortality in hospitalized patients, especially those with immunocompromised status. Options of the antifungal drugs available for successful treatment of drug-resistant biofilms are very few, and as such, new strategies need to be explored against them. The aim of this study was to evaluate the efficacy of phenylpropanoids of plant origin against planktonic cells, important virulence factors, and biofilm forms of C. albicans. Standard susceptibility testing protocol was used to evaluate the activities of 13 phenylpropanoids against planktonic growth. Their effects on adhesion and yeast-to-hyphae morphogenesis were studied in microplate-based methodologies. An in vitro biofilm model analyzed the phenylpropanoid-mediated prevention of biofilm development and mature biofilms using XTT-metabolic assay, crystal violet assay, and light microscopy. Six molecules exhibited fungistatic activity at ${\leq}0.5mg/ml$, of which four were fungicidal at low concentrations. Seven phenylpropanoids inhibited yeast-to-hyphae transition at low concentrations (0.031-0.5 mg/ml), whereas adhesion to the solid substrate was prevented in the range of 0.5-2 mg/ml. Treatment with ${\leq}0.5mg/ml$ concentrations of at least six small molecules resulted in significant (p < 0.05) inhibition of biofilm formation by C. albicans. Mature biofilms that are highly resistant to antifungal drugs were susceptible to low concentrations of 4 of the 13 molecules. This study revealed phenylpropanoids of plant origin as promising candidates to devise preventive strategies against drug-resistant biofilms of C. albicans.

• Parasites, Hosts and Diseases
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• 제53권1호
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• pp.43-49
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• 2015

The aim of the study was to explore the possible molecular markers of chloroquine resistance in Plasmodium vivax isolates in Thailand. A total of 30 P. vivax isolates were collected from a malaria endemic area along the Thai-Myanmar border in Mae Sot district of Thailand. Dried blood spot samples were collected for analysis of Pvmdr1 and Pvcrt-o polymorphisms. Blood samples ($100{\mu}l$) were collected by finger-prick for in vitro chloroquine susceptibility testing by schizont maturation inhibition assay. Based on the cut-off $IC_{50}$ of 100 nM, 19 (63.3%) isolates were classified as chloroquine resistant P. vivax isolates. Seven non-synonymous mutations and 2 synonymous were identified in Pvmdr1 gene. Y976F and F1076L mutations were detected in 7 (23.3%) and 16 isolates (53.3%), respectively. Analysis of Pvcrt-o gene revealed that all isolates were wild-type. Our results suggest that chloroquine resistance gene is now spreading in this area. Monitoring of chloroquine resistant molecular markers provide a useful tool for future control of P. vivax malaria.

• Tuberculosis and Respiratory Diseases
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• 제86권3호
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• pp.234-244
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• 2023

Background: Effective treatment of fluoroquinolone-resistant multidrug-resistant tuberculosis (FQr-MDR-TB) is difficult because of the limited number of available core anti-TB drugs and high rates of resistance to anti-TB drugs other than FQs. However, few studies have examined anti-TB drugs that are effective in treating patients with FQr-MDR-TB in a real-world setting. Methods: The impact of anti-TB drug use on treatment outcomes in patients with pulmonary FQr-MDR-TB was retrospectively evaluated using a nationwide integrated TB database (Korean Tuberculosis and Post-Tuberculosis). Data from 2011 to 2017 were included. Results: The study population consisted of 1,082 patients with FQr-MDR-TB. The overall treatment outcomes were as follows: treatment success (69.7%), death (13.7%), lost to follow-up or not evaluated (12.8%), and treatment failure (3.9%). On a propensity-score-matched multivariate logistic regression analysis, the use of bedaquiline (BDQ), linezolid (LZD), levofloxacin (LFX), cycloserine (CS), ethambutol (EMB), pyrazinamide, kanamycin (KM), prothionamide (PTO), and para-aminosalicylic acid against susceptible strains increased the treatment success rate (vs. unfavorable outcomes). The use of LFX, CS, EMB, and PTO against susceptible strains decreased the mortality (vs. treatment success). Conclusion: A therapeutic regimen guided by drug-susceptibility testing can improve the treatment of patients with pulmonary FQr-MDR-TB. In addition to core anti-TB drugs, such as BDQ and LZD, treatment of susceptible strains with later-generation FQs and KM may be beneficial for FQr-MDR-TB patients with limited treatment options.

• Tuberculosis and Respiratory Diseases
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• 제42권6호
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• pp.831-837
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• 1995

연구목적: 폐결핵 치료에서 약재내성은 큰 문제가 된다. 특히 다제 약제 내성은 환자 자신 뿐만 아니라 예방의학적 측면에서도 큰 문제가 되고 있다. 3차 의료기관에 오는 폐결핵 환자들에서 약제 내성의 발현 정도, 양상 및 관계되는 요인 등을 조사하여 내원 환자들의 향후 치료에 도움이 되는 지표를 알아 보고자 하였다. 대상 및 방법: 1986년 부터 1994년 사이 고신의료원 내과를 방문하여 폐결핵으로 진단되어 약제내성 검사를 한 141명의 환자를 대상으로 약제 내성률과 과거 치료 병력, 흉부 X-선 사진상 폐의 침범 정도와 공동의 유무 등의 관계를 후향적으로 조사하였다. 성적: 141 명중 59명(41.8%)에서 한 가지 약제 이상에 내성야 있었고 INH와 RIF에 동시 내성이 있는 경우는 139명중 29명(20.9%)였다. 과거에 결핵 치료를 63명중 40명(63.5%)에서 약제 내성이 있었고 24명(38.1%)에서 다제 약제 내성이 있었다. 과거 결핵치료 병력이 없는 78명중 19명(24.4%)에서 약제내성이 있었고 5명(6.5%)에서는 다제 약제 내성이 있었다. 약제별로는 INH내성이 39.0%로 가장 높았고 RIF(21.6%), EMB(16.3%), PAS(10.8%), SM(8.7%), PZA(8.0%) 순이었다. INH, RIF 및 PZA에 대한 내성은 과거 치료 병력이 있는 경우에서 높았고(odds ratio 각각 3.3, 7.2 및 10.8), 흉부 X-선 사진상 침범부위가 RIF 및 SM에 대한 내성률이 유의하게 높았다(odds ratio 각각 2.9, 2.8). 결론: 높은 약제 내성률로 보아 약제 감수성검사는 모든 환자들에게 시행해야 하겠으며, 그 결과가 나오기 전까지는 4가지 이상의 약제를 사용하는 것이 안전할 것으로 생각된다. 그리고 특히 과거에 치료한 병력이 있거나 진행된 폐결핵 환자의 경우는 철저한 임상적 및 세균학적인 추적관찰이 필요할 것으로 생각한다.

• Tuberculosis and Respiratory Diseases
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• 제59권6호
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• pp.619-624
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• 2005

연구배경 : 치료 경력이 있는 환자의 약제 내성은 진료의사의 처방의 적절성 및 환자의 복용 순응도를 복합적으로 나타내어 주는 지표가 될 수 있으므로, 우리나라에서 재치료 대상 결핵 환자에서 장기간의 약제내성률 추이를 파악하고자 하였다. 방 법 : 연도별 보건소 등록환자의 약제감수성 검사 결과 및 결핵연구원의 전산 입력된 자료를 활용하여 1981년부터 2004년 사이에 주요 약제에 대한 내성률의 변화를 분석하였다. 결 과 : Isoniazid 내성은 90%에서 20%로 감소하였다. Ethambutol 내성률도 45%에서 6%로 감소하였다. Rifampin 내성률은 13%에서 28%까지 증가하다가 13%까지 감소하였다. 다제내성률은 rifampin 내성률보다 약 2-3% 낮았다. Pyrazinamide 내성률은 5% 미만에서 10% 정도까지 증가하였다가 다시 5%까지 감소하였다. 2차약제에 대한 내성률은 1-2% 정도였다. 내성 빈도는 남녀 간에 차이가 없었으며, 대도시 지역이 중소도시/농촌지역보다 낮은 약제 내성률을 보였다. 결 론 : 우리나라보건소에 등록되는 재치료 대상 결핵 환자의 주요 항결핵 약제에 대한 내성률은 2004년을 기준으로 isoniazid 20%, rifampin 13%, 다제내성 11%, ethambutol 6%, pyrazinamide 5% 기타 2차 항결핵제에 1-3%로 나타났으며 1981년 이후 모든 항결핵 약제에서 그 내성률이 유의하게 감소하고 있었다.

• 한국축산식품학회지
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• 제41권5호
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• pp.883-893
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• 2021

Clostridium difficile present in feces of food animals may contaminate their meats and act as a potential source of C. difficile infection (CDI) to humans. C. difficile resistance to antibiotics, its production of toxins and spores play major roles in the pathogenesis of CDI. This is the first study to evaluate C. difficile prevalence in retail raw animal meats, its antibiotics susceptibilities and toxigenic activities in Al-Jouf, Saudi Arabia. Totally, 240 meat samples were tested. C. difficile was identified by standard microbiological and biochemical methods. Vitek-2 compact system confirmed C. difficile isolates were 15/240 (6.3%). Toxins A/B were not detected by Xpect C. difficile toxin A/B tests. Although all isolates were susceptible to vancomycin and metronidazole, variable degrees of reduced susceptibilities to moxifloxacin, clindamycin or tetracycline antibiotics were detected by Epsilon tests. C. difficile strains with reduced susceptibility to antibiotics should be investigated. Variability between the worldwide reported C. difficile contamination levels could be due to absence of a gold standard procedure for its isolation. Establishment of a unified testing algorithm for C. difficile detection in food products is definitely essential to evaluate the inter-regional variation in its prevalence on national and international levels. Proper use of antimicrobials during animal husbandry is crucial to control the selective drug pressure on C. difficile strains associated with food animals. Investigating the protective or pathogenic potential of non-toxigenic C. difficile strains and the possibility of gene transfer from certain toxigenic/ antibiotics-resistant to non-toxigenic/antibiotics-sensitive strains, respectively, should be worthy of attention.

• 대한수의학회지
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• 제61권4호
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• pp.37.1-37.6
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• 2021

This study evaluated the efficacy of a new, single-dose otic solution combining florfenicol, terbinafine, and mometasone furoate for the treatment of canine otitis externa (OE) in vitro and in vivo. Forty-one client-owned dogs with OE were included in the study and divided into a treatment group that received the test solution and a negative control group that received a normal saline solution. On day 0, the dogs were treated either with the test or the control solution and evaluated over 30 days. Clinical efficacy was evaluated by clinical signs and cytological organism counts. In vitro antimicrobial susceptibility was evaluated by the minimum inhibitory concentration (MIC). After treatment with the test solution, clinical signs continuously decreased and cytological scores were significantly reduced. The results of MIC testing showed that the test solution was potent against the common pathogenic causes of canine OE. In this study, the most common causative pathogens were Staphylococcus pseudintermedius, Pseudomonas spp. and Malassezia pachydermatis. No issues related to safety were identified. Based on these results, this new ototopical drug can be used as first line treatment for canine OE.

• 한국미생물·생명공학회지
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• 제51권4호
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• pp.432-440
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• 2023

Irrational and injudicious use of antibiotics, easy availability of them as over-the-counter drugs in economically developing countries, and unavailability of regulatory policies governing antimicrobial use in agriculture, animals, and humans, has led to the development of multi-drug resistance (MDR) bacteria. The use of medicinal plants can be considered as an alternative, with a consequent impact on microbial resistance. We tested extracts of Piper longum fruits as new natural products as agents for reversing the resistance to antibiotics. Six crude extracts of P. longum fruits were utilized against a clinical isolate of multidrug-resistant Staphylococcus aureus.The antibiotic susceptibility testing disc method was used in the antibiotic resistance reversal analysis. Apart from cefoxitin and erythromycin, all other antibiotics used (lincosamides [clindamycin], quinolones [levofloxacin and ciprofloxacin], and aminoglycosides [amikacin and gentamicin]) were enhanced by P. longum extracts. The extracts that showed the greatest synergy with the antibiotics were EAPL (ethyl acetate [extract of] P. longum), n-BPL (n-butanol [extract of] P. longum), and MPL (methanolic [extract of] P. longum The results of this study suggest that P. longum extracts have the ability to increase the effectiveness of different classes of antibiotics and reverse their resistance. However, future studies are needed to elucidate the molecular mechanisms behind the synergy between antibiotic and phytocompound(s) and identify the active biomolecules of P. longum responsible for the synergy in S. aureus.

• Journal of Genetic Medicine
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• 제5권2호
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• pp.89-93
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• 2008

"Personalized medicine," the goal of which is to provide better clinical care by applying patient's own genomic information to their health care is a global challenge for the $21^{st}$ century "genomic era." This is especially true in Korea, where provisions for clinical genetic services are inadequate for the existing demand, let alone future demands. Genomics-based knowledge and tools make it possible to approach each patient as a unique biological individual, which has led to a paradigm-shift in medical practice, giving it more of a predictive focus as compared with current treatment oriented approach. With recent advancements in genomics, many genetic tests, such as susceptibility genetic tests, have been developed for both rare single gene diseases and more common multifactorial diseases. Indeed, genetic tests for presymtomatic individuals and genetic tests for drug response have become widely available, and personalized medicine will face the challenge of assisting patients who use such tests to make appropriate and wise use of genetic risk assessment. A major challenge of genomic medicine lies in understanding and communicating disease risk in order to facilitate and support patients and their families in making informed decisions. Establishment of a health care system with provisions for genetic counseling as an integral part of health care service, in addition to genomic literacy of health care providers, is vital to meet this growing challenge. Realization of the promise of personalized medicine in the era of genomics for improvement of health care is dependent on further development of next generation sequencing technology and affordable sequencing test costs. Also necessary will be policy development concerning the ethical, legal and social issues of genomic medicine and an educated and ready medical community with clinical practice guidelines for genetic counseling and genetic testing.

• Tuberculosis and Respiratory Diseases
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• 제59권3호
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• pp.257-265
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• 2005

연구 배경 : 리팜핀 내성 균주에서 리파부틴 약제의 교차 내성정도와 리팜핀 내성-리파부틴 감수성 결핵균의 rpoB 유전자 돌연변이의 특성을 알아보고자 연구를 실시하였다. 연구 방법 : 감수성검사에서 리팜핀에 내성인 균주를 선정하여 리파부틴 농도 $0-80{\mu}g/ml$ 농도로 재접종하여 감수성 여부를 확인하였다. 리팜핀-내성균주 모두 염기서열 분석을 통하여 리파부틴 감수성과의 관계를 조사하였다. 역교잡 방법으로 리파부틴 감수성균을 구별하였다. 연구 결과 : 우리나라에서 분리된 리팜핀 내성인 201균주 중에서 41균주(20.4%)는 리파부틴에 감수성을 보였다. 리파부틴 감수성을 보이는 rpoB 유전자 돌연변이는 Leu511Pro, Ser512Arg, Gln513Glu, Asp516Ala, Asp516Gly, Asp516Val, Asp516Tyr, Ser522Leu, His526Asn, His526Leu, His526Cys, Arg529Pro, Leu533Pro 등 이었다. 역교잡 방법을 이용하였을 경우 rpoB 돌연변이를 가진 균주 중에서 리파부틴 감수성균의 민감도는 92.5%이었고, 특이도는 96.1%이었다. 결 론 : 리팜핀 내성균이라도 약 20.4% (95% 신뢰구간: 14.8% to 26.0%)가 리파부틴 약제에 감수성이므로, 우리나라의 다제내성 결핵환자의 치료에서도 리파부틴이 중요한 약제로서 역할을 할 수 있음이 밝혀졌다. 향후 다제내성 결핵 환자에서의 리파부틴의 치료 효과에 대한 임상적 연구가 필요하다.