Division of Respiratory and Critical Care Medicine, Department of Internal Medicine, Taichung Hospital, Ministry of Health and Welfare, Taichung, Taiwan; Graduate Institute of Clinical Medical Science, China Medical University, Taichung, Taiwan.
Department of Laboratory Medicine, China Medical University Hospital, Taichung, Taiwan.
J Microbiol Immunol Infect. 2017 Oct;50(5):604-612. doi: 10.1016/j.jmii.2015.10.002. Epub 2015 Dec 1.
Pulsed-field gel electrophoresis (PFGE) is the "gold standard" for epidemiological investigation of methicillin-resistant Staphylococcus aureus (MRSA), but several DNA sequence-based methods have been developed in MRSA typing because of the unambiguous results.
Ninety-one MRSA isolates were collected from the blood cultures of different patients from July 2008 to December 2008 in central Taiwan. The molecular characteristics of each isolate, including double locus sequence typing (DLST; spa and clfB typing), Staphylococcus cassette chromosome mec (SCCmec), and PFGE were determined for comparison.
Five major clfB types (types A-E), 18 spa types, 33 DLST genotypes, five SCCmec types, 17 pulsotypes have been observed. Three major DLST genotypes (A1-t002, C0-t037, and B1-t437) and two major pulsotypes (6 and 8) were identified. Most clfB type A isolates (97.1%) were SCCmec type II and all clfB type C isolates (100%) were SCCmec type III. Most clfB type B isolates (88.9%) were SCCmec type IV (59.3%) and V (29.6%). All (100%) clfB subtypes A1, A2, and C isolates and 70.4% of clfB type B isolates belonged to healthcare-associated-MRSA. The average congruence was 57.7% between DLST and PFGE, and 96.6% between clfB and SCCmec type. The index of discrimination of SCCmec, clfB, spa, PFGE, and DLST was 0.72, 0.79, 0.80, 0.81, and 0.87, respectively.
ClfB type has high congruence with SCCmec type. The DLST method in this study yielded a higher discriminatory power than PFGE in local investigation of molecular epidemiology of MRSA and a promising alternative to PFGE.
脉冲场凝胶电泳（PFGE）是耐甲氧西林金黄色葡萄球菌（MRSA）流行病学调查的“金标准”，但由于结果明确，已经开发了几种基于 DNA 序列的方法用于 MRSA 分型。
2008 年 7 月至 12 月，从台湾中部不同患者的血培养中收集了 91 株 MRSA 分离株。对每个分离株的分子特征（包括双重位点序列分型（DLST；spa 和 clfB 分型）、葡萄球菌盒式染色体 mec（SCCmec）和 PFGE）进行了确定，以进行比较。
观察到 5 种主要的 clfB 型（A-E 型）、18 种 spa 型、33 种 DLST 基因型、5 种 SCCmec 型、17 种脉冲型。确定了 3 种主要的 DLST 基因型（A1-t002、C0-t037 和 B1-t437）和 2 种主要的脉冲型（6 和 8）。大多数 clfB 型 A 分离株（97.1%）为 SCCmec 型 II，所有 clfB 型 C 分离株（100%）均为 SCCmec 型 III。大多数 clfB 型 B 分离株（88.9%）为 SCCmec 型 IV（59.3%）和 V（29.6%）。所有（100%）clfB 亚型 A1、A2 和 C 分离株以及 70.4%的 clfB 型 B 分离株属于与医疗保健相关的 MRSA。DLST 和 PFGE 之间的平均一致性为 57.7%，clfB 和 SCCmec 型之间的一致性为 96.6%。SCCmec、clfB、spa、PFGE 和 DLST 的鉴别指数分别为 0.72、0.79、0.80、0.81 和 0.87。
clfB 型与 SCCmec 型具有高度一致性。本研究中的 DLST 方法在本地调查 MRSA 的分子流行病学方面比 PFGE 具有更高的分辨力，是 PFGE 的一种有前途的替代方法。
