2007년부터 2015년까지 분리된 반코마이신 내성 Enterococcus faecium의 MLST 변화추세 : VRE의 MLST 변화추세
Comparison of Multilocus sequence typing change patterns of Vancomycin-resistant Enterococcus faecium in the past nine years
- 주제(키워드) VRE , MLST , MALDI-TOF
- 발행기관 아주대학교
- 지도교수 이위교
- 발행년도 2018
- 학위수여년월 2018. 2
- 학위명 박사
- 학과 및 전공 일반대학원 의학과
- 실제URI http://www.dcollection.net/handler/ajou/000000027543
- 본문언어 영어
- 저작권 아주대학교 논문은 저작권에 의해 보호받습니다.
초록/요약
Comparison of Multilocus sequence typing change patterns of Vancomycin resistant Enterococcus faecium in the past nine years Background : To understand the spread of Vancomycin Resistant Enterococcus (VRE) is an important component of hospital infection control measures. Multilocus sequence typing (MLST) is useful in determining the long–term evolutionary process and minimizes differences in experimental results across individuals and laboratories. It is also useful in determining evolutionary origins and backgrounds of bacterial species. This study carries out MLST analysis on vanA Vancomycin resistant Enterococcus faecium isolated from patient specimen in a single university hospital in the past nine years in order to observe changes in genetic evolution over time. Method : During the years from 2007 to 2015, 45 clinical isolates of vanA-containing E. faecium were collected from Ajou university hospital in Korea. Species were identified through the VitekII system (BioMerieux, Hazelwood, MO) and antibiotic susceptibility testing was performed by disk diffusion and E-test according to Clinical and Laboratory Standards Institute (CLSI) guidelines. To determine genetic relatedness, Matrix Assisted Laser Desorption Ionization-Time Of Flight mass spectrometry (MALDI-TOF MS) was employed. The multilocus sequence types (MLST) were determined to characterize the clonal diversity of the vanA Vancomycin resistant Enterococcus faecium isolates. Result : All isolates were highly resistant to ampicillin, teicoplanin, ciprofloxacin, and vancomycin whereas they were most susceptible to linezolid and quinupristin- dalfopristin. 45 clinical isolates were genetically unrelated according to MALDI-TOF MS analysis. MLST showed that the clinical isolates had 7 sequence types (ST), ST17(n=19) being the most common, followed by ST78(n=13), ST192(n=6), ST64(n=4), ST262(n=1), ST414(n=1) and ST981(n=1). Conclusion : The MLST analysis showed that the sequence types of most isolates belonged to clonal complex 17(CC17). This is consistent with outbreaks in hospitals. The study found that the most common type of separation was changed from ST78 to ST17. We had single observations for ST262, ST414 and ST981 but they appear to be random occurrences. MLST can be useful for speculating the genetic evolution of vanA containing E. faecium isolates.
more목차
Ⅰ.INTRODUCTION 1
Ⅱ. Material and Methods 5
A. Research Materials
1. Target strains 5
B. Research Methods
1. Antimicrobial susceptibility test 6
2. Realtime PCR 7
3. MALDITOF M/S 9
4. Multilocus sequence typing 11
Ⅲ. Results
1. Antimicrobial susceptibility test and resistant genotype 15
2. MALDITOF M/S 18
3. Multilocus sequence typing analysis 24
Ⅳ. DISCUSSION 28
Ⅴ. CONCLUSIONS 33
Ⅵ. REFERENCES 34
국문요약 41
