LABRESIS-Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, Rio Grande do Sul, Brazil.
PPGCF-Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil.
Microb Drug Resist. 2023 Feb;29(2):59-64. doi: 10.1089/mdr.2022.0012.
Delay in the results of standard phenotypic susceptibility tests is the main obstacle to adequate antibiotic treatment. For this reason, the European Committee for Antimicrobial Susceptibility Testing has proposed the Rapid Antimicrobial Susceptibility Testing for the disk diffusion method directly from blood culture. However, to date, there are no studies evaluating early readings of polymyxin B broth microdilution (BMD), the only standardized methodology for assessing susceptibility to polymyxins. This study aimed to evaluate modifications in the BMD technique for polymyxin B using fewer antibiotic dilutions and reading after an incubation time of 8-9 hr (early reading) in comparison to 16-20 hr of incubation (standard reading) for isolates of , complex, and . A total of 192 isolates of gram-negative bacteria were evaluated and the minimum inhibitory concentrations were read after early and standard incubations. The early reading presented 93.2% of essential agreement and 97.9% of categorical agreement with the standard reading of BMD. Only three isolates (2.2%) presented major errors and only one (1.7%) presented a very major error. These results indicate a high agreement between the early and the standard reading times of BMD of polymyxin B.
标准表型药敏试验结果的延迟是抗生素治疗的主要障碍。出于这个原因，欧洲抗菌药物敏感性试验委员会提出了直接从血培养进行快速药敏试验的方法。然而，迄今为止，尚无研究评估多粘菌素 B 肉汤微量稀释法（BMD）的早期读数，BMD 是评估多粘菌素敏感性的唯一标准化方法。本研究旨在评估使用更少抗生素稀释液和在 8-9 小时孵育时间（早期读数）与在 16-20 小时孵育时间（标准读数）进行比较时，BMD 技术对多粘菌素 B 的修改，用于评估 、 复合体和 。总共评估了 192 株革兰氏阴性菌，在早期和标准孵育后读取最小抑菌浓度。早期读数与 BMD 的标准读数具有 93.2%的基本一致性和 97.9%的分类一致性。只有三个分离株（2.2%）出现主要错误，只有一个（1.7%）出现非常大的错误。这些结果表明，多粘菌素 B 的 BMD 早期读数与标准读数之间具有高度一致性。
