Methicillin함유 배지에서 Methicillin 내성 Staphylococcus aureus의 증식 양상

이중희 충남대학교 대학원 1992 국내석사

The present study was undertaken to conform the paradoxic effect of methicillin on the methicillin resistant Staphylococcus aurous(MRSA) isolated from clinical specimens. Four strains of MRSA and one strain of methicillin sensitive Staphylococcus aurous(MRSA) were compared with their growth patterns in the Muller-Hinton(MH) and 50% serum broth containing 0.5x, 1x, 2x, 4x, and 8x minimum inhibitory concentrarion(MIC) of methicillin. The MICs of each strain were determined in MH broth with methicillin concentration ranged 0.125 to 4096mcg/ml. The growth patterns of these strains were evaluated a continuously monitored turbidimetred turbudimetric method with Temperature Gradient Biophotorecorder TN-112D in MH and 50% serum broth. The MIC of methicillin against the HRSA was lmcg/ml, and the growth patterns of this strain in MH and 50% serum broth containing 0.5xMIC of Methicillin were significantly inhibited that of 1xMIC of them at 12 and 18 hour after incubation. The HIC of methicillin against the MRSA 01 strain was 512mcg/ml, and the growth patterns of this strain in MH broth containing 0.5xMIC of methicillin were significantly inhibited than that of 1xMIC of methicillin, in the 50% serum broth, however, the growth patterns of this strain did not observed any differences each other. The MIC of the methicillin against the MRSA 02 strain was 64mcg/ml, and the growth patterns of this strain in MH and 50% serum broth containing 0.5 xMIC of methicillin were significantly inhibited than that of 1-4xMIC of thee. The MIC of the methicillin against the HRSA 03 strain was 512mcg/ml and the growth patterns of this strain in MH broth containing 0.5xMIC of methicillin were slightly inhibited than that of 1xMIC of them, in the 50% serum broth, however, this phenomenon did not observed. The MIC of methicillin against. the MRSA 04 strain was 12&mcg/ml, and the growth patterus of this strain in MH and 50% serum broth containing 0.5xMIC of methicillin were significantly inhibited than that of 1-4x MIC of them. These results suggest that. some stains of NRSA show paradoxic effect from 0.5xMIC to IxMIC of methicillin, but this effect will be neuralized with 50% serum in some strains of HRSA

Methicillin 내성 포도상 구균의 분자역학적 특성과 페니실린 결합 단백질 유전자의 중합효소 반응에 의한 동정

임헌길 建國大學校 大學院 1995 국내박사

PBP-2'을 발현시키는 유전자인 mecA 유전자는 methicillin 내성 Staphylococci의 염색체 DNA에 존재하고, methicillin 감수성 균주에는 존재하지 않는다. 그러므로 본 연구에서는 중합효소 연쇄반응을 실행하여 mecA 유전자 DNA 단편의 증폭 유무에 의한 methicillin 내성 Staphylococci의 동정에 대하여 연구를 하였다. 임상검체에서 분리된 Staphylococci에서 mecA 유전자를 검출을 위한 중합효소 연쇄반응의 시발체는 PBP-2' 유전자 염기서열에 기초한 5'-AAAATCGATGGTAAAGGTTGGC-3'와 5'-AGTTCTG CAGTACCGGATTTGC-3'를 사용하였으며, 기존의 항균제 검사상 의 methicillin 내성과 잘 일치됨을 관찰하였다. 중합효소 연쇄반응으로 중폭된 533 bp DNA가 methicillin 내성분리균주에서 모두 관찰되었고, metcillin 감수성 분리균주에서는 98.5%에서 관찰되지 않았다. Methicillin 고도 내성 Staphylococci의 mecA 유전자는 약 5.56 Kb HindⅢ 제한효소 단편에 위치하였다. 5. aureus 고도내성 14균주의 염색체 DNA를 정제하여 중합효소 연쇄반응에 의해 얻은 mecA 유전자의 증폭단편을 methicillin 유전자 probe DNA로 혼성화 하여 약 5.56 Kb HindⅢ 제한단편으로 혼성화됨을 관찰하였다. 클로닝된 mecA 유전자를 콜로니 혼성화로 확인하였으며, mecA 유전자가 재조합된 클룬을 분리하여 제한효소 HindⅢ로 재절단하여 Southern 혼성화로 mecA 유전자가 포함된 5.56 Kb DNA 단편이 클론된 것을 재확인하였다. Methicillin 내성 S. aureus의 mecA 유전자에 기초하여 합성한 시발체로 중합효소 연쇄반응을 실행하여 methicillin 내성 S, aureus와 methicillin 내성 S. epidermidis를 정확히 동정할수 있었다. The structural gene(mecA gene) of penicillin binding protein (PBP-2') is present in the chromosomal DNA of the methicillin- resistant Staphylococcal strains, but not in the sensitive ones. The goal of the present study was to estabilish an experimental evidence for the use of polymerase chain reaction(PCR) for culture identification and eventually clinical diagnosis of methicillin-resistant Staphylococci. Primers based on the DNA sequence of the mecA gene from methicillin-resistant Staphylococcus aureus were used in PCR to screen for the presence of this gene in Staphyloccal isolates from various clinical settings. Results obtained with PCRs were generally consistent with those of standard microbiological assays. Approximately 533 bp amplified DNA fragment by PCR was observed in the methicillin-resistant Staphylococcal isolates. In contrast, when the DNA fragment was not produced in the methicillin - sensitive Staphylococcal isolates. The mecA gene in methicillin-high resistant Staphylococci has been located on an approximately 5.56 Kb HindⅢ restriction fragment of the chromosomal DNA. The 533 bp PCR-generated probe hybridized to an approximately 5.56 Kb HindⅢ restriction fragment of DNA obtained from mecA-positive Staphylococcus aureus. No hybridization was occured with the template DNA obtained from the mecA- negative strain. The cloned mecA gene was verified by colony hyhridization. Also the 533 bp PCR-generated probe was hybridzed to an approximately 5.56 Kb HindⅢ restriction fragment of the DNA obtained from pHL-1201 recombinant. PCR with the primers based on the mecA gene from methicillin-resistant Staphylococcus aureus was successfully distinguished the methicillin-resistants from the methicillin- sensitive strains of Staphylococcus aureus and Staphylococcus epidemidis.

말 및 말 관련 종사자의 methicillin 내성 포도상구균의 유병율 조사

이상규 충북대학교 대학원 2013 국내석사

Methicillin 내성 포도상구균은 전세계적으로 사람과 동물에서 중요한 병인체로 주목받고 있다. 본 연구는 국내 말과 말을 취급하는 사람에서의 methicillin 내성 포도상구균 발생현황을 조사하고자 실시하였다. 국내 경주마 목장에 소재하는 총 195두의 말과 18명의 말을 취급하는 사람(8명의 수의사, 7명의 말관리사, 3명의 동물병원 직원)을 대상으로 하였다. 면봉을 이용하여 한쪽 비강에서 시료를 채취하여 세균수송배지에 보관 후 5% 양 혈액배지에서 37℃ 3일간 배양하여 포도상구균 존재여부를 확인하였다. 포도상구균은 16S rRNA 유전자 분석을 실시하여 동정하였으며, 동정된 포도상구균은 coagulase 검사를 실시하였다. Methicillin 저항성을 확인하기 위하여 oxacillin 디스크 검사와 함께 mecA 유전자 존재를 PCR을 통하여 확인하였다. 검사를 실시하였던 말 195두 중 64두가 포도상구균으로 동정되었으며, 이중 29두(44.6%)가 methicillin 내성 포도상구균으로 확인되었다. 말을 취급하는 18명 중 14명의 시료에서 포도상구균이 동정되었으며, 이중 12명(85.7%)의 시료에서 methicillin에 내성을 가지고 있는 포도상구균으로 확인되었다. 말과 사람에서 동정된 모든 methicillin 내성 포도상구균은 coagulase 음성으로 확인되었다. 또한 항생제의 사용기간이 긴 개체에서 사용기간이 짧았던 개체군보다 methicillin 내성 포도상구균이 높은 것으로 나타났다(P=0.002). 본 연구 결과는 사람과 말 사이에서 인수공통전파가 일어날 수 있음을 시사한다. Methicillin-resistant staphylococci (MRS) are emerging as important pathogens in humans and animals worldwide. The aim of this study was to investigate the prevalence of MRS in the racehorse population and in horse-related personnel in Korea. A total of 195 horses and 18 humans (eight veterinarians, three veterinary hospital staff, and seven horse-handlers) from racehorse farms in Korea were included in the study. The samples were collected from nasal cavities using bacterial transport medium and were cultivated on tryptic soy agar with 5% sheep blood for 3 days at 37°C to confirm the presence of Staphylococcus spp. Presumptive Staphylococcus spp. isolates were identified by 16S ribosomal RNA gene analysis. The coagulase test and oxacillin susceptibility tests were performed using the tube dilution and disk diffusion methods, respectively. The presence of the mecA gene was determined using a polymerase chain reaction assay. Of the 195 horses, 29 (15.6%) yielded 29 MRS isolates. Twelve (66.7%) of the 18 horse-related personnel yielded 12 MRS isolates. All of the MRS isolates from horses or horse-related personnel were identified as methicillin-resistant coagulase-negative staphylococci (MRCNS). The result of this study suggest that the prevalence of MRS increased with the duration of antibiotic use (P = 0.002). This study also provides evidence for the zoonotic transmission of MRCNS between horses and humans, although further investigations are needed.

Methicillin resistant staphylococcus aureus의 분자생물학적 역학 연구

김민정 부산대학교 대학원 1999 국내박사

Methicillin resistant Staphylococcus aureus (MRSA) are increasingly responsible for the outbreaks of nosocomaial infections around the world. Because MRSA are often resistant to antimicrobial agents and because due to current necessity to use non-β-lactam antimicrobial therapy, infections due to these organisms are difficult to treat. The purpose of this study was to explain how the genetic background contributes to the phenotypic expression of MRSA and to resolve the immediate and proper identification of nosocomial infections by the MRSA. A total of 120 MRSA strains, isolated through biochemical tests from clinical specimens of patients in Pusan National University Hospital from January 1996 to December 1997, were tested for epdemiological research. A number of antibiotic susceptibility tests and experiments such as phage typing, coagulase typing, and biotyping were conducted and the effects of disinfectants were verified. The relationship between the antibiotic resistant and resistant were verified. The relationship between the antibiotic resistant and resistant expression determinants were statistically analyzed through Bartholomow´s test. Themolecular-genetic experiments such as dot blot hybridizations, PCR, and Southern blot hybridization were compared in terms of the immediate and proper identification of the pathogens. The entity of dru sequence, the repeat unit of genes, was clarified particularly through mecA probe, and in terms of its arrangement the isolated MRSA strains were compared to find out whether or not there was any distinction. The results of this study are as follows. 1. Of the 200 strains of S. aureus, isolated from clinical specimens through biological and biochemical tests, 120 strains of MRSA and 80 strains of MSSA were identified through the antibiotic susceptibillity test. The optimal conditions to detect MRSA were at 30℃, pH 5.0 and 6% NaCl. β-lactamase and penicillinase producion were observed in 64 (32%) and 120 (100%) strains, respectively. 2. In the antibiotic susceptibility test, of the 120 strains at S. aureus, 120 (100%) strains in penicillin and 93 strains in erythromycin were resistant with the disc diffusion method, and 120 (100%) strains in penicillin, 85 (71%) strains in tetracycline and 80 strains (67%) in chloramphenicol were resistant with the agar dilution method. All the stains were sensitive to vancomycin with both methods. 3. The lytic group Ⅲ was the largest in number in the phage typing, A3b(25%) and A3a (16%) formed the majority in the biotyping. In Staphylococcal coagulase, the group Ⅳ (40%) was the largest, and the highest disinfectant effect was observed in TEGO-51, which was the disinfectant for the surface. 4. The plasmid profile of the 120 strains of MRSA could be categorized into three types, and the plasmid transfer by conjugation was not observed. The plasmid curing in penicillin, erythromycin and tetracycline was followed by the loss of resistance to antibiotics, and whether the strains were endogenous to rifampin, chloramphenicol, cephalosporine and methicillin was related to chromsomal DNA. 5. In the dot blot hybridization, using specific mecA gene probe, the mecA gene was detected in 118 out of MRSA strains and in 8 out of 30 MSSA in Group Ⅱ, in which the resistance to methicillin was induced. None of the mecA genes from either strain was detected in Group Ⅲ. In PCR, the amplified DNA band of 533 bp was confirmed in 118 strains of MRSA but not in MSSA. In the Southern blot hybridization, the signal of the amplified electrophoresis band in PCR was similarly observed. The PCR conditions to detect MRSA were more sensitive in 40 cycles than in 30 cycles, as 10 fg/㎖ of MRSA were detected. 6. The single amplified band of mec-related HVR was observed in all 120 MRSA, but not in MSSA. The size of PCR products was between 194 bp and 1,353 bp. HVR was classified into seven genotypes and the largest in number was genotype E. The nucleotide sequence of genotype E was similar to that of mec-related HVR and eight units were directly repeated. 7. The relationship between the loss of resistance to antibiotics and the strains with the specific plasmid was statistically significant, but while the relationship of the strains without plasmid was not. Also the relationship between the degree of resistance to methicillin, and β-lactamase production, penicillinase production and mecA gene possession was statistically significant.

Distrubution of mecl and mecRl Genes in Methicillin-Resistant Staphylococcus Clinical Strains : Methicillin-내성 황색구균에서 mec 조절 유전자의 분포

김명곤 경북대학교 대학원 1995 국내박사

Methicillin-내성 황색포도구균을 대상으로 PCR 기법으로 methicillin 내성유전자(mecA)를 확인하고, 이 유전자의 조절유전자인 mecRl 유전자와 mecI 유전자의 분포를 조사하여 이들이 methicillin 내성 기전에 어떻게 작용하는가를 알아보고자 하였다. mecRl 유전자와 mecI 유전자의 확인은 각 유전자에 특이한 primer로서 PCR을 실시하였는데, mecRl 유전자중 5' 말단 부위(membrane spanning portion)는 실험에 사용한 Methicillin-내생균 모두가 보유하였으나 3'부위(penicillin binding portion)는 실험에 사용한 54주중 46주가 보유하였으며 mecI 유전자는 이 중 10주만이 보유하고 있었다. 또한 mecI 유전자를 보유한 균주중 6주를 무작위로 선택하여 염기서열을 분석한 결과 6주 모두 point mutation과 같은 유전자 변이를 가진 것으로 확인되어 이 유전자가 mecA 유전자의 억제 조절유전자로 작용함을 시사하였다. Among the methicillin-resistant Staphylococcus aureus isolated in three different hospitals, the distributions and natures of the mec regulator genes mecI and mecRl which were identified on the chromosome of mecA-carrying Staphylococcus aureus were studied. Screening by polymerase chain reaction (PCR) experiment, the fact was demonstrated that at least a portion of the 5'-end region of the mecRl gene was carried by all MRSA strains. The mecA gene were detected in 48 of 54 strains by PCR and in 53 of 54 strains by dot blot hybridization. The mecRl (MS) gene, corresponding to the 310bp of the transmembrane domain of the mecRl structural gene, was detected among all the strains tested. The other mecRl(PB) gene, corresponding to the 319bp of the penicillin-binding domain of the mecRl gene, was detected among the 46 of 54 strains. The data suggested that these regulator genes were the original components of the additional mec region DNA of methicillin-resistant S. aureus. On the other hand, only 10 strains (MICs, ≥128μg/ml) were found to be positive for mecI gene. The mecI gene, which presumably codes for the repressor protein of the mecA gene, was found to carry a point mutated gene in all six mecI-positive methicillin-resistant S. aureus strains. The data suggested that the each mutated mecI gene was deleted or substituted among clinical isolates of methicillin-resistant S. aureus strains which showed high levels of resistance to methicillin.

Methicillin 耐性 葡萄球菌의 分離 및 그 性狀

최윤호 全南大學校 大學院 1980 국내석사

Strains of Staphylococcus aureus were isolated from the air of various places of Chonnam University Hospital and from the pus of patient's wounds. Degrees of their resistance to methicillin and some other biological characters were studied with the following results. 1. Of the 92 coagulase positive strains, only two(2.2%) were resistant to methicillin. 2. Minimal inhibitory concentration of the antibiotic against the two strains was higher when special sensitive screening techniques (incubating a t 30°C, for longer time on 5% sodium chloride agar medium, and a larger inoculum) were applied. 3. The methicillin-resistant strains were also highly resistant to penicillin, and producing penicillinase which was detected by the rapid iodometric method. 4. These two resistant strains fermented mannitol and lysed rabbit RBC.

Evaluation of the Penicillin Binding Protein 2a Latex Agglutination Test as a Sole Test for Confirmation of Methicillin Resistance in Staphylococcus pseudintermedius

박선영 서울대학교 대학원 2024 국내석사

Staphylococcus pseudintermedius (S. pseudintermedius) is a primary causative agent of canine topical skin and ear infections and systemic infections. There is an increasing prevalence of methicillin-resistant S. pseudintermedius, with many cases demonstrating multidrug resistance (MDR). For this reason, the importance of accurate and rapid detection of methicillin resistance has increased for appropriate treatment. The major mechanism of this resistance is the production of penicillin binding protein 2a (PBP2a), encoded by the mecA gene. PBP2a possesses transpeptidase activity similar to intrinsic PBPs, but structural differences result in a low affinity for β-lactams. Typically, disk diffusion and minimum inhibitory concentration (MIC) tests using cefoxitin or oxacillin are utilized to detect methicillin resistance in Staphylococci. Also, mecA polymerase chain reaction (PCR) or commercial assays designed to target PBP2a have been used. This study aimed to evaluate the PBP2a latex agglutination test (PBP2a LAT) originally designed for S. aureus and Coagulase-negative Staphylococci (CoNS), as an alternative approach to detect methicillin resistance in S. pseudintermedius. S. pseudintermedius isolates (n=100) collected from dogs diagnosed as pyoderma were evaluated. When accepting mecA PCR results as the gold standard of methicillin resistance, 69 isolates were methicillin-resistant, and 31 isolates were methicillin-susceptible. The PBP2a LAT exhibited a sensitivity of 100% (69/69) (95% confidence interval [CI], 94.8 to 100%) and specificity of 96.8% (30/31) (95% CI, 83.3 to 99.9%), which were same to those of oxacillin disk diffusion method. In conclusion, the utilization of the latex agglutination assay targeting PBP2a in canine S. pseudintermedius isolates could be a cost-efficient and time-saving method, serving as a sole test to confirm methicillin resistance. Keywords: Canine, mecA gene, methicillin resistance, penicillin binding protein 2a, Staphylococcus pseudintermedius Student Number: 2022-22993 Staphylococcus pseudintermedius (S. pseudintermedius)는 개의 피부와 귀에서의 국소 감염 및 전신 감염을 유발하는 주요 병원체이다. 메티실린 내성 S. pseudintermedius의 비율이 증가하고 있으며, 이들 중 대부분이 다재내성 균주로 분리된다. 때문에 적절한 치료를 위해 정확하고 빠른 메티실린 내성 평가에 대한 중요성은 높아지고 있다. 메티실린 내성의 주요한 기전은 mecA 유전자에 의해 매개되는 페니실린결합단백질2a의 합성이다. 페니실린결합단백질2a는 기존의 페니실린결합단백질과 유사한 transpeptidase 기능을 가지나 구조적인 차이로 베타락탐계 항생제에 낮은 결합력을 가진다. 일반적으로, Staphylococci에서 메티실린 내성을 평가하기 위해 세폭시틴 또는 옥사실린을 이용한 디스크 확산법, 최소억제농도실험법을 수행하며, mecA 중합효소연쇄반응 및 페니실린결합단백질2a을 대상으로 하는 검사법 또한 이용되고 있다. 본 연구는 S. pseudintermedius에서 메티실린 내성을 확인하는 대안적 방안으로서 S. aureus와 Coagulase-negative Staphylococci (CoNS)에서 효용성이 입증된 페니실린결합단백질2a 라텍스응집검사에 대한 평가를 수행하였다. 농피증을 진단받은 개로부터 분리한 S. pseudintermedius 균주 (n=100)를 대상으로 시험되었다. mecA PCR 결과를 메티실린 내성의 기준으로 삼았을 때, 69개의 균주가 메티실린 내성, 31개의 균주가 메티실린 감수성으로 확인되었다. PBP2a LAT의 민감도는 100% (69/69) (95% 신뢰 구간, 94.8%에서 100%), 특이도는 96.8% (30/31) (95% 신뢰 구간, 83.3에서 99.9%)로 평가되었으며, 이는 옥사실린 디스크 확산법과 동일한 민감도와 특이도를 나타냈다. 결론적으로, 페니실린결합단백질2a 라텍스응집검사가 개에서 분리한 S. pseudintermedius의 메티실린 내성 평가 시 비용 및 시간적으로 효율적인 단독 검사법으로서 활용될 수 있다는 것을 시사한다. 주요어 : 개, mecA 유전자, 메티실린 내성, 페니실린결합단백질2a, Staphylococcus pseudintermedius 학 번 : 2022-22993

Methicillin 내성 포도구균의 기타 항균제에 대한 감수성

이경수 경북대학교 1991 국내석사

1987 부터 1989 년동안 각종 임상가검물에서 분리된 204 주의 포도상 구균을 대상으로 methicillin 내성 포도상 구균 (MRSA)의 분리빈도를 조사하고 oxacillin screening 검사와 여러 가지 조건하에서 methicillin (Mt)의 최소 발육억제농도 (MIC)의 변화를 알아보았으며 MRSA을 대상으로 19 종의 항균제에 대한 감수성 검사를 실시하였다. 배양조건에 따른 Mt의 내성 발현정도는 4%의 NaCl을 첨가하여 35℃에서 72 시간 배양하였을 때 204주 중 33주(16.2%)의 포도상 구균이 Mt에 내성인 것으로 나타나 내성의 발현이 가장 잘 되었으며 oxacillin screening 검사시에도 33 주의 균주가 양성을 나타내었다. MRSA의 분리빈도는 87 년에 12주(9%), 88년에 11주(16.9%), 89년에 1주(20%)로 도합 24주(11.8%)의 분리율을 나타내었으며 해마다 MRSA가 증가함을 알 수 있었다. 19 종의 항균제에 대한 감수성 검사는 9 종부터 14 종의 항균제에 대한 중복내성까지 대체적으로 많은 항균제에 중복내성을 나타내었고 12 가지 항균제에 대한 중복내성이 8주로 가장 많은 분포를 나타내었다. Kanamycin과 Gentamicin에 100%의 내성을 보이며 amikacin에는 87.5%의 내성을 보여 aminoglycoside 계 항균제에 대한 내성은 아주 높게 나타났다. β-lactam 계 항균제에는 penicillin, cefoxitin에 100%의 내성을, cefotaxime, cephalothin, ceftazidime 등에는 75% 이상의 내성을 나타내었고 기타 chloramphenicol에 33.3%, tetracycline에 95.8%, rifampin에 91.7%, erythromycin에 87.5%의 내성을 나타내었다. 그러나, minocycline, vancomycin, trimethoprim-sulfamethoxazole에는 전 균주가 감수성을 나타내었으며 norfloxacin, ciprofloxacine, doxicycline에는 75% 이상의 감수성을 나타내었다. A total of 204 strains of Staphylococcus aureus isolates in 1987, 1988, and 1989 were studied for the frequency of methicillin-resistant S. aureus (MRSA) and antimicrobial susceptibility and also were examed for oxacillin screening test and change of minimal inhibitory concentration (MIC) of methicillin at the various conditions. When S.aureus were incubated on the agar media supplemented with 4 % NaCl at 35℃ for 72 hours, the most number strains expressed methicillin restance and 33 (16.2%) of 204 strains were resistant. In oxacillin screening test, oxacillin resistance was found in 33 (16.2%) of the 204 strains. Compared to the MIC of methicillin, oxacillin screening positive strains were not same strains of methicillin resistant S. aureus. Total frequency of MRSA was 24 (11.8%) of 204 strains. The frequencies of MRSA in 1987, 1988, and 1989 were 12 strains M), 11 strains (16.9%), and 1 strain (20%),. respectively and MRSA increased yearly. In vitro drug susceptibility test, all MRSA had multiple antibiotic resistance from 9 to 15 tested antibiotics and resistance to 12 antibiotics was most predominant. Resistance to kanamycin, gentamicin, penicillin and cefoxitin was 100 % and resistance to auikacin, cefotaxime, cephalothin, tetracycline, rifampin and erythromycin was more than 75 %. All MRSA was susceptible to minocycline, vancomycin and trimethoprim-sulfamethoxazole. Norfloxacin, ciprofloxacine and doxycycline was susceptible more than 75 % strains.

Propensity scores를 이용한 메티실린 내성 및 감수성 황색포도알균 균혈증의 비교 분석

박소연 경희대학교 대학원 2010 국내석사

Methicillin 내성 포도구균의 출현 빈도와 Ribotyping에 의한 동정

권병창 충남대학교 1997 국내석사

Methicillin-resistant Staphylococcus aureus (MRSA) is a recently recognized notorious nosocomial pathogen for multiple drug resistance. The commonly used disc diffusion antimicrobial susceptibility test is prone to give both false methicillin resistance and susceptibility. In this study the prevalence rates of MRSA in two general hospital, one Chungnam National University Hospital (CNUH) and the other Taejon Sun Hospital (SH) which were compared. Isolated of S.aureus, 130 from Chungnam National University Hospital, and 61 from Taejon Sun Hospital, which were isolated during September 1 to December 31, 1996. The amplification patterns produced were compared for their potential use in molecular epidermiologic analysis. This method, polymerase chain reaction(PCR) ribotyping, was applied to isolates of methicillin resistant S.aureus species. The patterns of the amplified mec A gene distinguished from related strains of all bacteria, oligonucleotide primers complementary to conserved regions of the 16s and 23s ribosomal DNA genes were used to amplify the 16s-23s intergenic spacer region of bacterial pathogens. The result were as follows: 1. In CNUH and SH the isolation rate of MRSA were 67.7% and 70.5% respectively. The average outcome of MRSA was 69.1%. 2. The MRSA frequently encountered in pus specimens (52.4%). 3. All strains were susceptible to vancomycin but were resistant to penicillin (97.4%), gentamicin (82.7%), erythromtcin (79.1%), tetracycline (74.9%) and oxacillin (69.8%). 4. 129 strains out of all MRSA were resistant to four or more antimicrobial agents. 5. Minimal inhibitory concentraitions (MIC) of methicillin against MRSA was over 16~128μg/㎖. 6. Specific band patterns for identification of MRSA were found by PCR ribotyping. Therfote PCR ribotyping is a useful epidemiological method for the infectious source of MRSA.