Nam Eun Young, Yang Soo-Jin, Kim Eu Suk, Cho Jeong Eun, Park Kyung-Hwa, Jung Sook-In, Yoon Nara, Kim Dong-Min, Lee Chang-Seop, Jang Hee-Chang, Park Yoonseon, Lee Kkot Sil, Kwak Yee Gyung, Lee Jae Hoon, Park Seong Yeon, Hwang Joo-Hee, Kim Moonsuk, Song Kyoung-Ho, Kim Hong Bin
1 Department of Internal Medicine, Seoul National University Bundang Hospital , Seongnam, Republic of Korea.
2 Department of Internal Medicine, Seoul National University College of Medicine , Seoul, Republic of Korea.
Microb Drug Resist. 2018 Jun;24(5):534-541. doi: 10.1089/mdr.2017.0212. Epub 2017 Oct 23.
This study was conducted to assess emergence of daptomycin-nonsusceptible (DAP-NS) phenotype in DAP-naive patients with invasive Staphylococcus aureus (ISA) infections in Korea. A total of 208 S. aureus clinical isolates were selected from a previous prospective study on ISA infections and evaluated for DAP-NS. Although DAP has never been introduced in Korea, five DAP-NS S. aureus strains (2.4%) were identified among 208 S. aureus strains collected from ISA infections. The DAP-NS phenotype was observed only in methicillin-resistant S. aureus (MRSA) strains, but not in methicillin-susceptible S. aureus strains. One DAP-NS MRSA strain belonged to sequence type 72 (ST72) and four were ST5 MRSA strains, three of which were heteroresistant vancomycin (VAN)-intermediate S. aureus. All these five DAP-NS MRSA strains were from healthcare-associated infections without prior exposure to VAN within 30 days. While the ST72 MRSA strain exhibited DAP-NS phenotype via charge repulsion mechanism, four ST5 DAP-NS S. aureus strains had charge-independent DAP-NS mechanism. None of the five DAP-NS strains displayed significant increase in cell wall thickness, indicating that altered cell wall thickness was not associated with the observed DAP-NS phenotype.
本研究旨在评估韩国初治的侵袭性金黄色葡萄球菌（ISA）感染患者中达托霉素不敏感（DAP-NS）表型的出现情况。从先前一项关于ISA感染的前瞻性研究中选取了208株金黄色葡萄球菌临床分离株，并对其进行DAP-NS评估。尽管达托霉素在韩国从未被引入，但在从ISA感染中收集的208株金黄色葡萄球菌菌株中，鉴定出5株DAP-NS金黄色葡萄球菌菌株（2.4%）。DAP-NS表型仅在耐甲氧西林金黄色葡萄球菌（MRSA）菌株中观察到，而在甲氧西林敏感金黄色葡萄球菌菌株中未观察到。1株DAP-NS MRSA菌株属于序列类型72（ST72），4株为ST5 MRSA菌株，其中3株为异质性万古霉素（VAN）中介金黄色葡萄球菌。所有这5株DAP-NS MRSA菌株均来自医疗保健相关感染，且在30天内未预先接触过VAN。虽然ST72 MRSA菌株通过电荷排斥机制表现出DAP-NS表型，但4株ST5 DAP-NS金黄色葡萄球菌菌株具有与电荷无关的DAP-NS机制。5株DAP-NS菌株均未显示细胞壁厚度有显著增加，这表明细胞壁厚度改变与观察到的DAP-NS表型无关。
