Wang Wei-Yao, Chen Yi-Hsin, Lee Yu-Lin, Chiu Chen-Feng, Tsao Shih-Ming
School of Medicine, Chung Shan Medical University, Taichung, Taiwan.
Department of Internal Medicine, Chung Shan Medical University Hospital, Taichung, Taiwan.
Infect Drug Resist. 2024 Mar 20;17:1121-1129. doi: 10.2147/IDR.S445211. eCollection 2024.
Determining oxacillin susceptibility using reference methods and automated systems is crucial for treating invasive infections caused by . This study compares the oxacillin susceptibility results from the two automated systems with agar dilution and correlates them with genotypes of invasive .
Non-duplicate invasive isolates were collected over an 11-year period. The oxacillin susceptibility was determined with Phoenix 100 (Jan 2011 to Aug 2018) or Vitek 2 (Sep 2018 to Dec 2021), and susceptibility for oxacillin and cefoxitin was determined with agar dilution. Methicillin-resistant (MRSA) was confirmed with existence, and the genotype was determined using SCC. The association between genotype and antibiotic susceptibility using two automated systems and agar dilution was evaluated.
A total of 842 invasive , including 443 + MRSA and 399 - MSSA, were collected. The susceptibility rates of oxacillin determined by two automated systems and agar dilution were 68.8% (76.8% for Phoenix 100 and 57.6% for Vitek 2) and 54.0%, respectively. When compared with the oxacillin susceptibility using agar dilution, the categorical agreement for Phoenix 100 and Vitek 2 were 0.46% and 0.88%, respectively ( < 0.001). One hundred and forty-three isolates were misinterpreted as oxacillin-susceptible (OSSA) using automated systems while comparing with agar dilution, among which molecularly community-associated MRSA (CA-MRSA) outnumbered healthcare-associated MRSA (HA-MRSA) (99 vs 34, < 0.001). There were 70 + OSSA (OS-MRSA) using agar dilution, among which 42 harbored SCC types were predominantly categorized as CA-MRSA (38, < 0.001).
The categorical agreement of Vitek 2 in determining oxacillin susceptibility and predicting existence is comparable with agar dilution, whereas Phoenix 100 is not. Most of those ORSA determined by agar dilution but misinterpreted as OSSA by automated systems and OS-MRSA are categorized as CA-MRSA.
使用参考方法和自动化系统确定苯唑西林敏感性对于治疗由……引起的侵袭性感染至关重要。本研究比较了两种自动化系统与琼脂稀释法检测苯唑西林敏感性的结果，并将它们与侵袭性……的基因型相关联。
在11年期间收集非重复的侵袭性分离株。使用Phoenix 100（2011年1月至2018年8月）或Vitek 2（2018年9月至2021年12月）测定苯唑西林敏感性，并用琼脂稀释法测定苯唑西林和头孢西丁的敏感性。通过……的存在确认耐甲氧西林……（MRSA），并使用SCC测定基因型。评估了使用两种自动化系统和琼脂稀释法时基因型与抗生素敏感性之间的关联。
共收集了842株侵袭性……，包括443株+MRSA和399株-MSSA。两种自动化系统和琼脂稀释法测定的苯唑西林敏感性率分别为68.8%（Phoenix 100为76.8%，Vitek 2为57.6%）和54.0%。与琼脂稀释法检测苯唑西林敏感性相比，Phoenix 100和Vitek 2的分类一致性分别为0.46%和0.88%（<0.001）。与琼脂稀释法比较时，143株分离株使用自动化系统被误判为苯唑西林敏感……（OSSA），其中分子社区相关MRSA（CA-MRSA）的数量超过医疗保健相关MRSA（HA-MRSA）（99比34，<0.001）。使用琼脂稀释法时有70株+OSSA（OS-MRSA），其中42株携带SCC类型，主要归类为CA-MRSA（38株，<0.001）。
Vitek 2在确定苯唑西林敏感性和预测……存在方面的分类一致性与琼脂稀释法相当，而Phoenix 100则不然。大多数通过琼脂稀释法判定为ORSA但被自动化系统误判为OSSA的菌株以及OS-MRSA被归类为CA-MRSA。
