Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci

碩士 === 國立臺灣大學 === 醫學檢驗暨生物技術學研究所 === 105 === Viridans group streptococci (VGS) are important flora in human. Most species reside as normal flora in the human respiratory, urogenital, and gastrointestinal tracts. Despite the low virulence, several studies have shown that many species in this group are...

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Main Authors: Tai-Fen Lee, 李岱芬
Other Authors: 鄧麗珍
Format: Others
Language:zh-TW
Published: 2017
Online Access:http://ndltd.ncl.edu.tw/handle/53c5b3
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spelling ndltd-TW-105NTU051080022019-05-15T23:17:02Z http://ndltd.ncl.edu.tw/handle/53c5b3 Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci 評估兩套質譜分析儀於草綠色鏈球菌的鑑定效果 Tai-Fen Lee 李岱芬 碩士 國立臺灣大學 醫學檢驗暨生物技術學研究所 105 Viridans group streptococci (VGS) are important flora in human. Most species reside as normal flora in the human respiratory, urogenital, and gastrointestinal tracts. Despite the low virulence, several studies have shown that many species in this group are associated with infections like endocarditis, meningitis, abscesses, and septicemia, especially in patients with different underlying conditions can cause serious infection. The nomenclature and classification have been under constant renewal, mainly due to new molecular typing methods. At present, the species of VGS can be divided into following five major groups according to their 16S rRNA sequences, Streptococcus bovis group, Streptococcus anginosus group, Streptococcus mitis group, Streptococcus mutans group and Streptococcus salivarius group. The API tests (bioMerieux, API 20S, API Rapid ID 32 Strep) or the automated commercial kits (Vitek GPI card, MicroScan GP and Phoenix SMIC) are usually used in the clinical microbiology laboratories to identify VGS. In National Taiwan University Hospital, the Phoenix 100 panel (BD) is used as an identification method for VGS when the blood culture was positive or the sterile site was positive. Recently, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) fingerprinting has been introduced as a routine microbial identification tool and found widespread acceptance thanks to its broad species coverage and superior turn around time. In this study, the commercial biochemical panels and MALDI-TOF MS systems were evaluated for identification of VGS. The 27 ATCC strains were selected to check MALDI-TOF MS database and 110 clinical blood culture positive isolates from Jan 2015 to Jun 2015 in the NTUH were collected to evaluate the two identification systems. Among the 31 S. anginosus group isolates, 3 isolates were misidentified in Phoenix system and 5 isolates were misidentified in VITEK 2 system but all the isolates were identified correctly in MALDI-TOF MS system. In the 7 S. salivarius group isolates, 1 isolate was misidentified in VITEK 2 system and another isolate needed more tests to confirm. In the 22 S. bovis group isolates, 2 isolates were misidentified in Phoenix system and 2 isolates needed more tests to confirm. Among the 46 S. mitis group isolates, 4 isolates had no result and 6 isolates were misidentified in Phoenix system and 2 isolates had no result in VITEK 2 system; 24 isolates were misidentified in MALDI Biotyper and 2 isolates had no result in VITEK MS system. These results suggested that the MALDI-TOF systems at present can offer a good alternative for the identification of VGS and perform as well as or better than the commercial biochemical methods. However, there are still some challenges in the identification of Streptococcus oralis and Streptococcus mitis. 鄧麗珍 2017 學位論文 ; thesis 49 zh-TW
collection NDLTD
language zh-TW
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sources NDLTD
description 碩士 === 國立臺灣大學 === 醫學檢驗暨生物技術學研究所 === 105 === Viridans group streptococci (VGS) are important flora in human. Most species reside as normal flora in the human respiratory, urogenital, and gastrointestinal tracts. Despite the low virulence, several studies have shown that many species in this group are associated with infections like endocarditis, meningitis, abscesses, and septicemia, especially in patients with different underlying conditions can cause serious infection. The nomenclature and classification have been under constant renewal, mainly due to new molecular typing methods. At present, the species of VGS can be divided into following five major groups according to their 16S rRNA sequences, Streptococcus bovis group, Streptococcus anginosus group, Streptococcus mitis group, Streptococcus mutans group and Streptococcus salivarius group. The API tests (bioMerieux, API 20S, API Rapid ID 32 Strep) or the automated commercial kits (Vitek GPI card, MicroScan GP and Phoenix SMIC) are usually used in the clinical microbiology laboratories to identify VGS. In National Taiwan University Hospital, the Phoenix 100 panel (BD) is used as an identification method for VGS when the blood culture was positive or the sterile site was positive. Recently, matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) fingerprinting has been introduced as a routine microbial identification tool and found widespread acceptance thanks to its broad species coverage and superior turn around time. In this study, the commercial biochemical panels and MALDI-TOF MS systems were evaluated for identification of VGS. The 27 ATCC strains were selected to check MALDI-TOF MS database and 110 clinical blood culture positive isolates from Jan 2015 to Jun 2015 in the NTUH were collected to evaluate the two identification systems. Among the 31 S. anginosus group isolates, 3 isolates were misidentified in Phoenix system and 5 isolates were misidentified in VITEK 2 system but all the isolates were identified correctly in MALDI-TOF MS system. In the 7 S. salivarius group isolates, 1 isolate was misidentified in VITEK 2 system and another isolate needed more tests to confirm. In the 22 S. bovis group isolates, 2 isolates were misidentified in Phoenix system and 2 isolates needed more tests to confirm. Among the 46 S. mitis group isolates, 4 isolates had no result and 6 isolates were misidentified in Phoenix system and 2 isolates had no result in VITEK 2 system; 24 isolates were misidentified in MALDI Biotyper and 2 isolates had no result in VITEK MS system. These results suggested that the MALDI-TOF systems at present can offer a good alternative for the identification of VGS and perform as well as or better than the commercial biochemical methods. However, there are still some challenges in the identification of Streptococcus oralis and Streptococcus mitis.
author2 鄧麗珍
author_facet 鄧麗珍
Tai-Fen Lee
李岱芬
author Tai-Fen Lee
李岱芬
spellingShingle Tai-Fen Lee
李岱芬
Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
author_sort Tai-Fen Lee
title Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
title_short Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
title_full Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
title_fullStr Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
title_full_unstemmed Evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
title_sort evaluation of two matrix-assisted laser desorption ionization-time of flight mass spectrometry systems for identification of viridans group streptococci
publishDate 2017
url http://ndltd.ncl.edu.tw/handle/53c5b3
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