• 한방재활의학과학회지
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• 제30권1호
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• pp.31-45
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• 2020

Objectives In this study, we investigated the antimicrobial activity of a 70% ethanol extract of Maneung-hwan (MEH), which is prescribed by practitioners of oriental medicine for use against methicillin-resistant Staphylococcus aureus (MRSA). Methods The antibacterial activity of MEH against MRSA strains was evaluated using the disc diffusion method, broth microdilution method (minimal inhibitory concentration, MIC), checkerboard dilution test, and time-kill test. The mechanism of action of MEH was investigated by bacteriolysis using detergents or ATPase inhibitors Additionally, mRNA and protein expression were investigated by quantitative reverse transcription-polymerase chain reaction and western blot assay, respectively. Results The MIC of MEH was 25~1,600 ㎍/mL against all the tested bacterial strains. We showed that MEH extract exerts strong antibacterial activity. In the checkerboard dilution test, the fractional inhibitory concentration index of MEH in combination with antibiotics indicated synergism or partial synergism against S. aureus. The time-kill study indicated that the growth of the tested bacteria was considerably inhibited after a 24-h treatment with MEH and selected antibiotics. To measure the cell membrane permeability, MEH (3.9 ㎍/mL) was combined with Triton X-100 (TX) at various concentrations N,N-dicyclohexylcarbodimide (DCCD) was also tested as an ATPase inhibitor. TX and DCCD cooperation against S. aureus exhibited synergistic action. Accordingly, the antimicrobial activity of MEH in the context of cell membrane rupture and ATPase inhibition was assessed. Additionally, the expression of genes and proteins associated with resistance was reduced after exposing MRSA to MEH. Conclusions These results suggest that MEH possesses antibacterial activity and acts as a potential natural antibiotic against MRSA.

• Journal of Microbiology and Biotechnology
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• 제19권7호
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• pp.734-741
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• 2009

Recently, strains of methicillin-resistant Staphylococcus aureus (MRSA) with reduced susceptibility to vancomycin (VCM) have been clinically isolated. The antibacterial activity of a new drug, linezolid (LZD), in such a strain was evaluated by measuring bacterial metabolic activity. A total of 73 MRSA strains having various susceptibilities to VCM were subjected to a novel and highly sensitive chemiluminescence-based assay. LZD MIC in the tested strains, measured by the microbroth dilution method, was within the range 1-4 mg/l (mostly ${\leq}2$mg/l), except for one LZD-resistant strain (NRS127; MIC=7 mg/l), and showed no correlation with VCM resistance. The chemiluminescence assay demonstrated that bacterial metabolic activity was strongly suppressed with increasing LZD concentration. The chemiluminescence intensity curve had a low baseline activity without tailing in most strains. The present results suggest that LZD has strong antibacterial activity against MRSA strains, and would be effective for treatment of infections that are poorly responsive to VCM. The chemiluminescence assay facilitated sensitive and discriminative susceptibility testing within a relatively short time.

• Journal of Microbiology and Biotechnology
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• 제32권12호
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• pp.1537-1546
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• 2022

Staphylococcus aureus is a cause of high mortality in humans and therefore it is necessary to prevent its transmission and reduce infections. Our goals in this research were to investigate the frequency of methicillin-resistant S. aureus (MRSA) in Taif, Saudi Arabia, and assess the relationship between the phenotypic antimicrobial sensitivity patterns and the genes responsible for resistance. In addition, we examined the antimicrobial efficiency and application of silver nanoparticles (AgNPs) against MRSA isolates. Seventy-two nasal swabs were taken from patients; MRSA was cultivated on Mannitol Salt Agar supplemented with methicillin, and 16S rRNA sequencing was conducted in addition to morphological and biochemical identification. Specific resistance genes such as ermAC, aacA-aphD, tetKM, vatABC and mecA were PCR-amplified and resistance plasmids were also investigated. The MRSA incidence was ~49 % among the 72 S. aureus isolates and all MRSA strains were resistant to oxacillin, penicillin, and cefoxitin. However, vancomycin, linezolid, teicoplanin, mupirocin, and rifampicin were effective against 100% of MRSA strains. About 61% of MRSA strains exhibited multidrug resistance and were resistant to 3-12 antimicrobial medications (MDR). Methicillin resistance gene mecA was presented in all MDR-MRSA strains. Most MDR-MRSA contained a plasmid of > 10 kb. To overcome bacterial resistance, AgNPs were applied and displayed high antimicrobial activity and synergistic effect with penicillin. Our findings may help establish programs to control bacterial spread in communities as AgNPs appeared to exert a synergistic effect with penicillin to control bacterial resistance.

• 대한임상검사과학회지
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• 제48권3호
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• pp.202-209
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• 2016

본 연구는 methicillin-resistant Staphylococcus aureus(MRSA)로부터, 독소 유전자형과 항생제 내성의 상관 관계를 결정하는 것을 목표로 하였다. 2014년 1월~12월까지 전남 순천의 한 병원 중환자실의 임상검체 2,664건에서 얻어진 MRSA 52균주를 분리하였다. 유전자들이 암호화하고 있는 mecA, 장독소(staphylococcal enterotoxins; sea, seb, sec, seg, seh, sei, sej), 독성 쇼크 증상독소-1 (toxic shock syndrome toxin-1; tst-1), 표피박탈성독소(exfoliative toxin; eta, etb), 백혈구 용해 독소(Panton-Valentine leukocidin; pvl)를 특이적 프라이머를 이용한 multiplex PCR로 증폭 검출 하였다. 독소 유전자 seg와 sei 유전자가 각각 40균주(76.9%)로 가장 많은 보유율을 나타냈으며 다음으로 tst 34균주(65.4%) 순으로 검출 되었으며 eta, etb, sea, sed, see, seh, sej와 pvl 유전자들은 검출 되지 않았다. 2개 이상의 독소 유전자를 동시에 보유한 조합의 MRSA는 40균주(76.9%) 였는데 5개 유전자(seb, sec, seg, sei, tst)를 동시 보유한 조합이 28균주(53.8%)로 가장 많은 분포를 보였으며 다음으로 seg, sei 유전자 동시 보유 조합으로 6균주(11.5%)에서 나타났다. 유전자들 간의 동시 보유율은 72.5~100%로서 특정한 독소 유전자 seb, sec, seg, sei와 tst 유전자간의 상관성이 높게 나타났다. 특정 다수의 독소유전자(seb, sec, seg, sei, tst)를 동시에 보유한 균주들이 개별적 독소 유전자를 보유한 균주(seb, sec, tst)와의 항생제 내성의 상관성은 ciprofloxacin, clindamycin, erythromycin 항생제에 100% 내성을 보임으로서 공통적으로 포함된 seb, sec, tst 유전자와 이 항생제의 내성과는 밀접한 연관이 있음을 알았다.

• 미생물학회지
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• 제43권4호
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• pp.346-350
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• 2007

1994년에서 2005년 사이 부산지역의 임상검체와 건강인의 비강에서 분리된 Staphylococcus aureus의 coagulase 혈청형의 변화를 조사하였다. 총 715균주에서 methicillin 내성 S. aureus (MRSA)는 임상균주로 408주였으며, 나머지 307주는 methicillin 감수성(MSSA) 균주로서, 8종(I-VIII)의 coagulase 혈청형이 분리되었다. MRSA 균주에서 가장 분리율이 높은 coagulase 혈청형은 II형(54.3%, 222/408)이었으며, 다음으로 IV형(24.7%), III형(10.9%), V형(5.2%)순으로 나타났으며, MSSA 균주에서는 VII형(30.9%, 95/307), IV형(22.2%), V형(22.2%), II형(7.1%)의 순으로, 균주간에 큰 차이를 나타내었다. 분석 연도별 coagulase 혈청형을 비교한 결과 큰 변화가 관찰되었다. MRSA 균주에서 혈청형 V형은 1997년까지 분리되지 않았으나, 2005년에는 18.5% (20/108)로 증가되었고, III형은 1994년 27.0% (31/115)에서 2005년 0.9% (1/108)로 감소되었다. 또한 MSSA 균주에서도 유사한 경향을 나타내었으나, II형의 경우 2005년도 균주에서는 분리되지 않았다. 이와 같은 결과에서 S. aureus의 coagulase 항원성 전이에 따른 혈청형의 변화를 확인하였다.

• 대한한방내과학회지
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• 제23권2호
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• pp.298-305
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• 2002

These cases were performed on the bases of clinical consideration about patients who had Methicillin-Resistant Staphylococcus aureus(MRSA) infection. One patient was a 67-years-old women who had sequela of inter cranial hemorrhage & inter ventricular hemorrhage, hypertention, urinary tract infection and pneumonia. Clinical symptoms were intermittent fever, sputum, Lt. side hemiparesis and dysphagia. She was chronic, repeated infection state. It could be regarded as "unpreparedness of the spirit which animates and controls the universe; 正氣虛", the oriental term which indicates a condition of chronic disease or general weakness. According to the oriental medicine principle, oriental medicine was taken such as Wunggunza-tang(六君子湯) and the patient had taken a turn for the better. After 3 months, MRSA infection diappeared. The other patient was a 43-years-old women who had Both brain stem infarction, Lt. cerebellar infarction, hypercholesterolemia, urinary tract infection and pneumonia, Clinical symptoms were quadriplegia, dysphagia(levin tube insert state), aphasia, respiration disorder(tracheostomy cannular keep state) and sputum. She was chronic, repeated infection state. It could be regarded as "unpreparedness of spleen energy, unpreparedness of both energy and blood; 脾氣虛, 氣血兩虛", the oriental term which indicates a condition of chronic disease or immunodeficiency. According to the oriental medicine principle, oriental medicine was taken such as Bojungyggi-tang(補中益氣湯), Palmul-tang(八物湯) and the patient had taken a turn for the better. After I month, MRSA was turned into Escherichia coli.

• 미생물학회지
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• 제36권3호
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• pp.216-220
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• 2000

부산시 동아대학병원으로 내원한 83명의 환자 가건물로부터 methcillin 내성 Stphylococcus aureus(MRSA) 88 균주를 분리하고 응고 효소의 유형별 분석과 다약제 내성의 상호 관계를 연구하였다. 농(64.7%), 객담(26.2%), 기타 혈액, 장액 및 뇨로부터 균주가 분리되었고 mec A 유전자에 특이적인 primer 5'-AAAATCGATGGTAAAGGTT-GGC-3'와 5'-AGTTCTGCAGTACCGGATTTGC3'를 사용하여 PCR을 한결과 86균주에서 mec 유전자가 확인되었다. 응고효소형은 제 III형이 50%m IV형이 12.5%, III형이 6.8%, I, VII, VIII형이 4.5%로 제 II형이 가장 많았으며 제 V형은 전혀 분리되지 않았다. 응고효소형의 병동별 분포는 일반외과에서 제 II형이, 이비인후과 외래에서는 제 IV형이 우점종으로 분리되었다. 항균제 감수성 시험결과, vancomycin과 teicoplanin에서 전균주가 감수성을 나타내었었고 penionillin, cephalothin, erythromycin, gentamycin, imipenem, clindamycin, ciprofloxacin과 oxacillin등 8가지의 항균제에 대하여 동시내성을 나타낸 균주가 71주 (81%)였다. 항균제 내성과 응고효소형과의 상관관계는 없었다.

• 약학회지
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• 제36권5호
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• pp.486-490
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• 1992

The clinical isolate Staphylococcus aureus SA2 was resistant to ampicillin, Chloramphenicol, clindamycin, erythromycin, gentamicin, kanamycin, methicillin, streptomycin, and tobramycin and harboured more than two kinds of plasmids. Transformation experiment demonstrated that 40.98-kb plasmid(pKH2) encoded resistance to ampicillin, clindamycin, erythromycin, kanamycin, and streptomycin. The cleavage map of a pKH2 was determined by restriction enzyme mapping techniques. Cleavage map is given for BamHI, BglI, BstEII, SalI and XhoI.

• 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.

• 한국균학회지
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• 제48권1호
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• pp.15-27
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• 2020

본 연구에서는 methicillin resistant Staphylococcus aureus subsp. aureus (MRSA) KCCM 40510 및 Bacillus cereus KCTC 3624 균주에 대한 항균활성을 보유한 균류 Penicillium rubefaciens NNIBRFG5039를 경북 상주시 도남동 공기 중으로부터 분리·동정하였고, 배양조건에 따른 균사체 생육 및 항균활성을 비교하였다. 그 결과, P. rubefaciens NNIBRFG5039는 PDB 배지, 배양온도 30℃, 초기 pH 6.5로 배양하였을 때 항균활성이 가장 높게 나타나는 것을 확인하였다. 최적조건하에서 5L fermenter를 이용하여 배양시간에 따른 균사체 건조중량 및 항균활성을 비교한 결과, 배양 5일째에 생장 및 항균활성이 가장 높았다. P. rubefaciens NNIBRFG5039의 배양여액의 항균활성 스펙트럼을 조사한 결과, methicillin-resistant Staphylococcus aureus subsp. aureus CCARM 3089·3090·3091·3095와 KCCM 40510, Bacillus cereus KCTC 3624, B.subtilis KACC 10111, Filobasidium neoformans KCTC 7902, Enterococcus faecalis KCCM 11814에 대해서도 항균활성을 가지는 것을 확인하였다. 또한, P. rubefaciens NNIBRFG5039의 배양여액으로부터 항균활성 후보물질을 각종 크로마토그라피법으로 순수분리하고, NMR과 ESI-MS 등의 기기분석을 실시하여 구조를 (S)-6-hydroxymellein (1)으로 동정하였다.