Bondi Alessandro, Curtoni Antonio, Peradotto Marco, Zanotto Elisa, Boattini Matteo, Bianco Gabriele, Iannaccone Marco, Barbui Anna Maria, Cavallo Rossana, Costa Cristina
Microbiology and Virology Unit, University Hospital Città della Salute e della Scienza di Torino, University of Turin, 10126 Turin, Italy.
Department of Public Healt and Pediatric Sciences, University of Turin, 10126 Turin, Italy.
Antibiotics (Basel). 2023 Jun 26;12(7):1106. doi: 10.3390/antibiotics12071106.
Fosfomycin is an old bactericidal drug that has gained increasing interest in the last decade for its potential use in multi-drug resistant gram-negative infections. However, evidence on fosfomycin susceptibility testing reports a poor correlation between commercial methods vs. reference agar dilution (AD) for (EB). The study aimed at assessing the performance of two automated systems for the determination of fosfomycin susceptibility in clinical isolates.
Fosfomycin susceptibility testing results of two collections of 100 non-duplicate clinical EB strains obtained using two different platforms (BD Phoenix and MicroScan WalkAway Plus) were compared with those obtained by AD. Categorical agreement (CA), major error (ME) and very major error (VME) rates were calculated.
BD Phoenix exhibited a 6.9% rate of false-resistant results and achieved a CA of 69%, whereas MicroScan WalkAway Plus achieved 3.7% of false-resistant results and 72% of CA. Both automated systems showed poor detection of resistant isolates, with 49.1% and 56.2% of false-susceptible results for BD Phoenix and Microscan WalkAway Plus, respectively.
Overall, agar dilution remains the most suitable method for routine laboratory antimicrobial susceptibility testing of fosfomycin on strains, given the poor performance of automated systems. The application of both automated systems, in the clinical laboratories reporting of fosfomycin, should be reviewed in light of the accuracy results falling below the acceptable threshold.
磷霉素是一种古老的杀菌药物，在过去十年中，因其在多重耐药革兰氏阴性菌感染中的潜在用途而受到越来越多的关注。然而，关于磷霉素药敏试验的证据表明，商业方法与参考琼脂稀释法（AD）之间对于[具体细菌名称未给出]（EB）的相关性较差。本研究旨在评估两种自动化系统在临床分离株中测定磷霉素敏感性的性能。
将使用两种不同平台（BD Phoenix和MicroScan WalkAway Plus）获得的两组100株非重复临床EB菌株的磷霉素药敏试验结果与琼脂稀释法获得的结果进行比较。计算分类一致性（CA）、主要错误（ME）和非常主要错误（VME）率。
BD Phoenix显示出6.9%的假耐药结果率，分类一致性为69%，而MicroScan WalkAway Plus的假耐药结果率为3.7%，分类一致性为72%。两种自动化系统对耐药菌株的检测均较差，BD Phoenix和MicroScan WalkAway Plus的假敏感结果分别为49.1%和56.2%。
总体而言，鉴于自动化系统性能不佳，琼脂稀释法仍是实验室对[具体细菌名称未给出]菌株进行磷霉素常规抗菌药敏试验的最合适方法。鉴于准确性结果低于可接受阈值，临床实验室在报告磷霉素时对这两种自动化系统的应用应重新评估。
