• Journal of Microbiology and Biotechnology
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• 제20권2호
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• pp.425-432
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• 2010

Staphylococcus intermedius is a common cause of otitis externa, pyoderma, and wound infections in companion animals. Although S. intermedius infections are rare in humans, it is zoonotic, with several case reports describing fatal human infections. Presently, we sought to isolate S. intermedius strains from various sources at animal hospitals nationwide in Korea, examine their antibiotic susceptibilities, and determine the possibility of horizontal transmission between animals and humans. Pulsed-field gel electrophoresis (pFGE) was used to compare the mecA gene in S. intermedius strains from humans, animals, and the environment in animal hospitals. A total of 119 S. intermedius strains were isolated from 529 samples. Using the disk diffusion method, over 90% of the isolates were found to be susceptible to cephalothin, amoxicillin-clavulanic acid, vancomycin, imipenem, nitroflurantoin, and amikacin, whereas 97.5% and 98.3% of the isolates were resistant to penicillin and ampicillin, respectively. Among the 39 S. intermedius strains harboring mecA, similar PFGE patterns were observed between seven isolates from an animal, two isolates from veterinary staff, and the environment in one animal hospital, and single isolates from an animal and a veterinarian at another hospital. This result suggests the possibility of horizontal transmission of S. intermedius containing mecA between humans, animals, and the environment in animal hospitals and also emphasizes on the importance of S. intermedius with mecA as a possible emerging threat to public health.

• 한국미생물·생명공학회지
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• 제41권3호
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• pp.335-340
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• 2013

선복화(Inula britannica flowers) 메탄올 추출물을 이용하여 methicillin에 저항성이 있는 Staphylococcus aureus (MRSA)에 대한 항균효과를 검증하였다. 선복화 메탄올 추출물은 다량의 quercetin을 함유한 것으로 분석되었다. 세 종류의 MRSA에 대한 항균효과는 disc diffusion method에 의해 확인되었고, 최소저해농도(MIC) 및 최소사멸농도(MBC)는 각각 0.625 mg/ml-1.25 mg/ml, 2.5 mg/ml로 확인되었다. 이들 MRSA 중 S. aureus ATCC 33591가 가장 민감한 작용을 하였으며, 이 균에 대해서 작용기작을 확인하였다. 시간에 따른 저해 정도와 형태관찰을 통해 선복화 메탄올 추출물이 항균활성을 갖는 것을 확인할 수 있었다. 메탄올 추출물의 resistant gene에 대한 영향은 mRNA 상에서 mecA와 mecRI gene의 발현감소와 mecI gene의 발현증가를 통해 메티실린 내성을 감소시키는 것을 알 수 있었다. 따라서 선복화 메탄올추출물은 MRSA에 대한 항균효과를 가지는 천연 항균성 소재로서의 가능성을 확인할 수 있었다.

• Tuberculosis and Respiratory Diseases
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• 제72권3호
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• pp.293-301
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• 2012

Background: Ventilator-associated pneumonia (VAP) requires prompt and appropriate treatment. Since methicillin-resistant Staphylococcus aureus (MRSA) is a frequent pathogen in VAP, rapid identification of it, is pivotal. Our aim was to evaluate the utility of quantitative polymerase chain reaction (qPCR) as a useful method for etiologic diagnoses of MRSA pneumonia. Methods: We performed qPCR for mecA, S. aureus-specific femA-SA, and S. epidermidis-specific femA-SE genes from bronchoalveolar lavage or bronchial washing samples obtained from clinically-suspected VAP. Molecular identification of MRSA was based on the presence of the mecA and femA-SA gene, with the absence of the femA-SE gene. To compensate for the experimental and clinical conditions, we spiked an internal control in the course of DNA extraction. We estimated number of colony-forming units per mL (CFU/mL) of MRSA samples through a standard curve of a serially-diluted reference MRSA strain. We compared the threshold cycle (Ct) value with the microbiologic results of MRSA. Results: We obtained the mecA gene standard curve, which showed the detection limit of the mecA gene to be 100 fg, which corresponds to a copy number of 30. We chose cut-off Ct values of 27.94 (equivalent to $1{\times}10^4$ CFU/mL) and 21.78 (equivalent to $1{\times}10^5$ CFU/mL). The sensitivity and specificity of our assay were 88.9% and 88.9% respectively, when compared with quantitative cultures. Conclusion: Our results were valuable for diagnosing and identifying pathogens involved in VAP. We believe our modified qPCR is an appropriate tool for the rapid diagnosis of clinical pathogens regarding patients in the intensive care unit.

• Journal of Microbiology and Biotechnology
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• 제13권3호
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• pp.354-359
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• 2003

Multiplex-PCR protocols were designed in order to make a rapid identification of MRSA. MecA, femB, and 165 rRNA genes were amplified for making a detection of MRSA. The incidence of MRSA in the clinical isolates of Staphylococcus aureus was examined by using a multiplex-PCR assay. The mecA gene was detected in 266 strains out of 336 clinical isolates of S. aureus, thus the incidence of MRSA was approximately 76.5%. The MRSAs of 247 strains (96.1%) showed resistance to more than eight species of the antimicrobial agents tested. The isolates of MRSA showed 27 different antimicrobial-resistant patterns. The results indicate that many different MRSA strains having high multidrug resistance are actually prevalent in Korea. Also, VISA was screened from the MRSA. Two strains were grown on the BHI agar plate supplemented with $8\;\mu\textrm{g}/ml$ of vancomycin at a frequency of $1/10^8$ colony forming units or higher.

• 한국미생물·생명공학회지
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• 제51권4호
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• pp.545-547
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• 2023

Staphylococcus epidermidis is a normal flora of human skin and is occasionally associated with pathogenic infections. We report the complete genome sequence of methicillin-resistant Staphylococcus epidermidis strain Z0118SE0272 isolated from the residential environment sharing by a companion dog and dwellers. Resistance to cefoxitin was observed in the strain, whereas it was susceptible to erythromycin, clindamycin, quinupristin-dalfopristin, trimethoprim-sulfamethoxazole, mupirocin, vancomycin, teicoplanin, linezolid, and tigecycline. The strain Z0118SE0272 identified as sequence type 130 possessed the mecA gene responsible for methicillin resistance, which composed the new type of staphylococcal cassette chromosome mec elements lacking mecRI.

• Journal of Microbiology and Biotechnology
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• 제19권10호
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• pp.1265-1270
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• 2009

The objectives of this study were to determine the antibiotypes, SCCmec subtypes, PVL carriage, and genetic diversity of MRSA strains from a tertiary hospital. Sixty-six MRSA strains were selected randomly (2003, 2004, and 2007) and tested for the Panton-Valentine leukocidin gene, mecA gene, and SCCmec type via a PCR. The antibiograms were determined using a standard disc diffusion method, and the genetic diversity of the isolates was determined by PFGE. Thirty-four antibiograms were obtained, with 55% of the 66 strains exhibiting resistance to more than 4 antimicrobials. All the isolates remained susceptible to vancomycin, and low resistance rates were noted for fusidic acid (11%), rifampicin (11%), and clindamycin acid (19%). The MRSA isolates that were multisensitive (n=12) were SCCmec type IV, whereas the rest (multiresistant) were SCCmec type III. Only two isolates (SCCmec type IV) tested positive for PVL, whereas all the isolates were mecA-positive. The PFGE was very discriminative and subtyped the 66 isolates into 55 pulsotypes (F=0.31-1.0). The multisensitive isolates were distinctly different from the multidrug-resistant MRSA. In conclusion, no vancomycin-resistant isolate was observed. The Malaysian MDR MRSA isolates were mostly SCCmec type III and negative for PVL. These strains were genetically distinct from the SCCmec type IV strains, which were sensitive to SXT, tetracycline, and erythromycin. Only two strains were SCCmec IV and PVL-positive. The infections in the hospital concerned were probably caused by multiple subtypes of MRSA.

• 한국동물위생학회지
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• 제33권3호
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• pp.233-240
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• 2010

Methicillin-resistant coagulase-negative staphylococci (MRCNS) were isolated from the respiratory sites of chickens in 4 farms and slaughter house located in Chungnam provinces. Isolation of coagulase-negative staphylococci (CNS) was positive for 61 (26.6%) of the 229 chickens tested, and isolation of MRCNS was positive for 17 (27.9%) of the isolated CNS. A total of 17 MRCNS isolates were selected and subjected to identification. Of the 17 MRCNS isolates selected, 6 were identified as Staphylococcus cohnii, 2 as S. saprophyticus, 3 as S. simulans, 3 as S. lentus, 2 as S. carnosus, and 1 as S. xylosus. The MRCNS isolates were resistant to many beta-lactam antibiotics, and some isolates were also resistant to macrolide and aminoglycoside antibiotics. The mecA gene was detected in some isolates of each MRCNS strains. The mecA-positive isolates were classified into five staphylococcal cassette chromosome mec (SCCmec). SCCmec types I to IV were detected in isolates from chickens.

• 대한의생명과학회지
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• 제11권4호
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• pp.525-531
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• 2005

Staphylococcus aureus is a major cause of nosocomial infections and is one of the most commonly isolated bacterial species in the hospital and continues to be an important pathogen in both community and hospital-acquired infection. Methicillin resistant S. aureus (MRSA), which is associated with hospitals is now being isolated in the community. The purpose of this study is to investigate the carrier rate of S. aureus in the community, antibiotic resistance patterns of the organism, detection of MRSA and mecA gene in MRSA. Ninety strains $(46.4\%)$ of S. aureus were isolated from the nasal specimens of 194 elementary school students. Eighty-nine strains $(98.9\%)$ of 90 S. aureus were resistant to penicilin, 36 strains $(40.0\%)$ to erythromycin, 14 strains $(15.6\%)$ to fusidic acid, 11 strains $(12.2\%)$ to gentamycin, 9 strains $(10.0\%)$ to tobramycin, 5 strains $(5.6\%)$ to oxacillin, 4 strains $(4.4\%)$ to clindamycin, 2 strains $(2.2\%)$ to tetracycline, 1 strains $(1.1\%)$ to fosfomycin. None of $90(0\%)$ S. aureus isolates was resistant to ciprpfloxacin, trimethoprim/sulfamethoxazole, levofloxacin, linezolid, moxifloxacin, nitrofurantoin, norfloxacin, rifampicin, quinupristin/dalfopristin, teicoplanin, and vancomycin. Five strains $(5.6\%)$ of 90 S. aureus isolates were MRSA. The mecA gene was detected from five MRSA strains by PCR.

• Journal of Microbiology
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• 제45권4호
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• pp.350-357
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• 2007

This study was conducted in an effort to evaluate the antimicrobial activity and antibiotic-resistant gene regulation from Saliva miltiorrhiza Bunge on methicillin-resistant Staphylococcus aureus (MRSA). A variety of solvent fractions and methanol extracts of S. miltiorrhiza Bunge were tested in order to determine its antimicrobial activities against S. aureus and MRSA. As a result, the hexane fraction of S. miltiorrhiza Bunge evidenced the highest levels of antimicrobial activity against S. aureus and MRSA. The MICs of the hexane fraction against various MRSA specimens were $64. The hexane fraction evidenced inhibitory effects superior to those of the chloroform fraction. The results showed inhibition zones of hexane (16 mm) and chloroform (14 mm) fractions against MRSA KCCM 40511 at $1,000{\mu}g/disc$. The hexane and chloroform fractions inhibited the expression of the resistant genes, mecA, mecR1, and femA in mRNA. Moreover, the results of Western blotting assays indicated that the hexane and chloroform fractions inhibited the expression of the resistant protein, PBP2a. These results reveal that the hexane and chloroform fractions of S. miltiorrhiza Bunge may prove to be a valuable choice for studies targeted toward the development of new antimicrobial agents.

• 미생물학회지
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• 제41권1호
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• pp.24-37
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• 2005

국내 사육 하우 염소, 돼지, 개, 닭 및 마우스 등을 포함한 각종 동물과 사람환자에서 분리한 총 116주의 S. aureus 분리주에 대해서 5종의 PCR 기법을 적용하여 분자역학적 특성을 분석하였다. 먼저 종특이 유전자(SSG: aroA, coa, nuc 및 spa-gene)의 다양성을 PCR 기법으로 조사하였고, 또한 약제내성의 MRSA 균주의 분포양상과 내독소(Enterotoxin)산생유전자(SE)의 분포양상에 대해서도 조사하였다. 그리고 이 연궁선 수행한 5종의 PCR 기법 들이 생산한 개별성적을 객관적으로 비교하여, 가장 신뢰도 높고 효율적 PCR기법을 선발하였다. 먼저 PCR기법을 적용한 SSG의 분포양상 조사에서는 $nuc-gene\;(100\%)$, $spa-gene\;(91.4\%)$, $coa-gene\;(87.9\%)$, 및 $aroA-gene\;(26.7\%)$의 빈도로 조사되었다. 그리고 aroA와 coa-gene PCR 증폭산물에 대한 RsaI과 AluI 효소로 소화시킨 RELP 성적에서 coa-Bene PCR-RFLP에서는 모두 10 type의 con-type이 동정되었고, 그중 coa-3 type (809 bp)이 닭, 마우스, MRSA 및 사람유래 균주를 포함한 총 36주 $(33.0\%)$로서 가장 대표적인 genotype으로 결정되었다. 반면에 aroA-gene PCR-RELP에서는 단지 7 type의 genotype만이 산생되어 대조를 보였고, 17주 $(73.9\%)$가 대표적인 그룹으로 분류되었다. 한편 spa-gene PCR에서는 총 11 type의 spa-type이 확인되었고, 그중 spa-7 type (9 repeats; 263 bp)이 한우, 닭, 개, 염소, 마우스 및 MRSA 균주 등을 포함한 총 39주 $(34.8\%)$로서 가장 대표적인 genotype으로 결정되었다. 또한 총 116주에 대해 MRSA 균주의신속한 검출을 위해서 mecA-gene PCR을 적용하였던 바, 단지 사람유래의 14주 $(12.1\%)$에서만 양성의 증폭산물 (533 bp)이 검출되었고, 이들 증폭된 PCR산물의 유전학적 검증을 위해 HhaI으로 소화시켰던바 14주 모두 $(100\%)$가 알려진 2개의 DNA band (332 & 201 bp)로 양분되어 유전자수준에서 MRSA 양성균주로 검증되었다. 한편 내독소 산생유전자 (SE-gene)는 multiplex-PCR기법으로 조사하였으며 sea-gene $(63.7\%)$이 가장 지배적이었고, 이어서 seb-gene $(10.0\%)$ 및 sec-gene $(7.2\%)$의 순서였다. 특히 sea+sec의 2종의 SE genes를 보유한 균주도 11주로서 가장 많았으며 그 외에도 sea+seb (2주)및 seb+see (1주) genes를 보유한 균주도 함께 검출되었다. 최종적으로 5종의 PCR기법들이 생산한 성적들을 수치 (SID)로 변환하여 객관적으로 감별능력 (DA)을 비교하였던바, aroA-gene PCR-RFLP는 가장 저조한 DA [SID=0.462]을 나타내었고, 반면에 coa-gene PCR-RELP는 5종의 분석기법 중에서 가장 신뢰도 높은 DA [SID=0.894]을 발현하였다. 따라서 현재의 연구결과con-gene PCR-RELP기법이 사람을 포함한 다양한 동물종유래 S. aureus 균주들의 유전학적 분석목적에 가장 신뢰도 높고 감별능력이 뛰어난 분석기법으로 선발되었다.