• 대한약침학회지
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• 제25권1호
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• pp.37-45
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• 2022

Objectives: The quorum-sensing-inhibitory and anti-biofilm activities of the methanol extract of E. globulus leaves were determined against clinically isolated multidrug-resistant Pseudomonas aeruginosa. Methods: The preliminary anti-quorum-sensing (AQS) activity of eucalyptus was investigated against a biosensor strain Chromobacterium violaceum ATCC 12472 (CV12472) by using the agar well diffusion method. The effect of sub-minimum inhibitory concentrations (sub-MICs) of the methanol extract of eucalyptus on different quorum-sensing-regulated virulence factors, such as swarming motility, pyocyanin pigment, exopolysaccharide (EPS), and biofilm formation, against clinical isolates (CIs 2, 3, and 4) and reference PA01 of Pseudomonas aeruginosa were determined using the swarm diameter (mm)-measurement method, chloroform extraction method, phenol (5%)-sulphuric acid (concentrated) method, and the microtiter plate assay respectively, and the inhibition (%) in formation were calculated. Results: The preliminary AQS activity (violacein pigment inhibition) of eucalyptus was confirmed against Chromobacterium violaceum ATCC 12472 (CV12472). The eucalyptus extract also showed concentration-dependent inhibition (%) of swarming motility, pyocyanin pigment, EPS, and biofilm formation in different CIs and PA01 of P. aeruginosa. Conclusion: Our results revealed the effectiveness of the E. globulus extract for the regulation of quorum-sensing-dependent virulence factors and biofilm formation at a reduced dose (sub-MICs) and suggest that E. globulus may be a therapeutic agent for curing and controlling bacterial infection and thereby reducing the possibility of resistance development in pathogenic strains.

• Clinical and Experimental Pediatrics
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• 제52권5호
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• pp.529-537
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• 2009

Drug-resistant tuberculosis in children has important implications for both the patients and tuberculosis control programs. In Korea, among all new patients, the isoniazid resistance rate was 9.9% and multidrug-resistant tuberculosis rate was 2.7% in 2004 (in patients aged 10-19 yr, the multidrug-resistant tuberculosis rate reached 2.1%). Tuberculosis in pediatric patients is difficult to diagnose because many children have nonspecific clinical signs and the detection rates of acid-fast bacilli smears and cultures are low. Therefore, every effort should be made to identify adult sources and obtain information on drug susceptibility because symptomatic adult patients have a higher chance of culture positivity and drug-susceptibility patterns are the same in most adult-child pair patients. Korean children are at significant risk of drug-resistant tuberculosis. As the isoniazid resistance rate is greater than 4% among the new cases in Korea, a four-drug regimen should be considered for initial treatment of children with active tuberculosis, unless drug-susceptibility test results are available. Treatment of drug-resistant tuberculosis in children is challenging and there are only few available data. Tuberculosis control programs should be continuous with specific focus on pediatric populations because they can serve as reservoirs for future active cases. Further studies are needed regarding treatment of drug-resistant tuberculosis in children.

• Tuberculosis and Respiratory Diseases
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• 제85권2호
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• pp.111-121
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• 2022

Multidrug-resistant tuberculosis (MDR-TB) is caused by an organism that is resistant to both rifampicin and isoniazid. Extensively drug-resistant TB, a rare type of MDR-TB, is caused by an organism that is resistant to quinolone and one of group A TB drugs (i.e., linezolid and bedaquiline). In 2018, the World Health Organization revised the groupings of TB medicines and reclassified linezolid as a group A drug for the treatment of MDR-TB. Linezolid is a synthetic antimicrobial agent in the oxazolidinone class. Although linezolid has a good efficacy, it can cause substantial adverse events, especially hematologic toxicity. In both TB infection and linezolid mechanism of action, mitochondrial dysfunction plays an important role. In this concise review, characteristics of linezolid as an anti-TB drug are summarized, including its efficacy, pathogenesis of hematologic toxicity highlighting mitochondrial dysfunction, and the monitoring and management of hematologic toxicity.

• 한국미생물·생명공학회지
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• 제38권1호
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• pp.77-83
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• 2010

산사자는 전 세계적으로 이용되는 있는 식용/약용 생물자원 중 하나이다. 본 연구에서는 산사자의 유용 생리활성 검토를 위한 연구의 일환으로, 산사자의 methanol 추출물 및 이의 n-hexane, ethylacetate, butanol 분획물 및 물 잔류물을 조제하여 항생제 다제내성 Pseudomonas aeruginosa 및 Candida sp.를 포함하는 다양한 병원성 및 식중독 미생물에 대한 항균활성을 평가하였다. 산사자의 methan이 추출물은 그람 양성 및 음성의 다양한 세균에 대해 항균활성을 나타내였고, 이의 분획물 중 ethylacetate 및 butanol 분획물은 Listeria monocytogen, Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Salmonella typhimurium, Proteus vulgaris, Escherichia coli는 물론 10종의 항생제 내성 병원성 Pseudomonas aeruginosa에 대해서도 우수한 항세균 활성을 나타내었다(최소생육억제농도 1.0~7.5 mg/mL). 또한 ethylacetate 및 butan이 분획물은 일부의 Candida sp.에 대해서도 항균활성을 나타내였다. 한편 n-hexane 분획물을 제외한 산사자 methan이 추출물 및 분획물들은 $500\;{\mu}g/mL$ 농도까지 인간적혈구에 대한 용혈현상을 보이지 않았으며, n-hexane 분획물은 $500\;{\mu}g/mL$ 농도에서 약 9.9%의 미미한 용혈활성을 나타내었다. 이러한 결과는 산사자가 다양한 세균의 제어는 물론 항생제 내성 Pseudomonas aeruginosa 제어를 위한 생물자원으로 개발 기능함을 제시하고 있다.

• 한국미생물·생명공학회지
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• 제45권4호
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• pp.354-357
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• 2017

There is an increase in the presence of drug-resistant staphylococci outside of the nosocomial and healthcare setting. Although the presence of staphylococci has been studied in several public spaces, nothing is known on the presence of staphylococci in public libraries. Book surfaces from public libraries in the East London area, United Kingdom were swabbed and cultured and identity of the isolates determined by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry (MS). Seven different staphylococcal species were identified by MALDI-TOF-MS analysis. This short study provides evidence of the presence of multidrug-resistant staphylococci in public libraries in the East London area.

• 약학회지
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• 제46권2호
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• pp.108-112
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• 2002

Drug resistance is one of the most significant impediments to successful chemotherapy of cancer. Multidrug-resistance (MDR) is characterized by decreased cellular sensitivity to anticancer agents due to the overexpression of P-glycoprotein. By employing a resistant subline of HCT15 to adriamycin (CL02), we undertook the screening for agents which were effective to multidrug-resistant cancer cells. As a result, a myxobacterial strain JW150 was selected for study since an activity against CL02 cells was discovered in the strain. Cytotoxicity-guided fractionation of the culture broth led to the isolation of cystothiazole A and melithiazole F. The producing organism was identified as Myxococcus stipitatus by taxonomic comparison with type strains of Myxococcus sp. as well as its morphological and physiological characteristics. Cystothiazole A and melithiazole F demonstrated potent cytotoxicity against certain human cancer cells with $IC_{50}$ values ranging from 0.03~ $0.72{\mu}{\textrm{g}}$/ml. Both compounds were interestingly as active against drug-resistant sublines CL02 and CP70 as against the corresponding parental cells.

• Tuberculosis and Respiratory Diseases
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• 제80권4호
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• pp.336-343
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• 2017

Despite progress made in tuberculosis control worldwide, the disease burden and treatment outcome of multidrug-resistant tuberculosis (MDR-TB) patients have remained virtually unchanged. In 2016, the World Health Organization released new guidelines for the management of MDR-TB. The guidelines are intended to improve detection rate and treatment outcome for MDR-TB through novel, rapid molecular testing and shorter treatment regimens. Key changes include the introduction of a new, shorter MDR-TB treatment regimen, a new classification of medicines and updated recommendations for the conventional MDR-TB regimen. This paper will review these key changes and discuss the potential issues with regard to the implementation of these guidelines in South Korea.

• 약학회지
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• 제39권1호
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• pp.6-9
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• 1995

The clinical isolate Staphylococcus aureus SA2 had four kinds of plasmids and was resistant to ampicillin, chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, methicillin, streptomycin, tetracycline and tobramycin. Transformation experiment demonstrated that 4.44 kb plasmid(pKH6) encoded resistance to tetracycline. The cleavage map of pKH6 was determined by restriction enzyme mapping techniques. The cleavage map is given for EcoRV, HindIII, HpaI, HpaII, KpnI and Xbal. Restriction endonucleases BamHl, BglI, BGIII, BstEII, EcoRI, HaellI, PstI, PvuII, SalI, Smal, and Xhol have no site on this plasmid. The restriction map revealed extensive structural homology between pKH6 and pT181.

• Tuberculosis and Respiratory Diseases
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• 제84권1호
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• pp.74-83
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• 2021

Background: This study compared the treatment outcomes of patients with multidrug-resistant tuberculosis (MDR-TB) before and after the implementation of public-private mix (PPM). Factors affecting treatment success were also investigated. Methods: Data from culture-confirmed pulmonary MDR-TB patients who commenced MDR-TB treatment at Pusan National University Hospital between January 2003 and December 2017 were retrospectively reviewed. Patients were divided into two groups in terms of PPM status: pre-PPM period, patients who commenced MDR-TB treatment between 2003 and 2010; and post-PPM period, patients treated between 2011 and 2017. Results: A total of 176 patients were included (64 and 112 in the pre- and post-PPM periods, respectively). 36.9% of the patients were resistant to a fluoroquinolone or a second-line injectable drug, or both. The overall treatment success rate was 72.7%. The success rate of post-PPM patients was higher than that of pre-PPM patients (79.5% vs. 60.9%, p=0.008). Also, loss to follow-up was lower in the post-PPM period (5.4% vs. 15.6%, p=0.023). In multivariate regression analysis, age ≥65 years, body mass index ≤18.5 kg/m², previous TB treatment, bilateral lung involvement, and extensively drug-resistant (XDR)- or pre-XDR-TB were associated with poorer treatment outcomes. However, the use of bedaquiline or delamanid for ≥1 month increased the treatment success. Conclusion: The treatment success rate in MDR-TB patients was higher in the post-PPM period than in the pre-PPM period, particularly because of the low rate of loss to follow-up. To ensure comprehensive patient-centered PPM in South Korea, investment and other support must be adequate.

• 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.