LABRESIS-Laboratório de Pesquisa em Resistência Bacteriana, Hospital de Clínicas de Porto Alegre, Porto Alegre, RS, Brazil.
Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
J Clin Microbiol. 2018 Aug 27;56(9). doi: 10.1128/JCM.00325-18. Print 2018 Sep.
The aim of this study was to evaluate the two rapid colorimetric methods (CNPt-Direct and Blue-Carba) for the detection of carbapenemase production directly from blood culture in a routine microbiology laboratory. The methods were initially evaluated on spiked blood cultures with 61 carbapenemase-positive isolates. Afterwards, they were used in blood cultures (314 samples were evaluated) obtained from patients in a routine microbiology laboratory during a period of 6 months. The colorimetric methods were compared to the conventional culture of blood. The results of the spiked blood cultures indicated that both colorimetric methods presented positive results for the vast majority (95%) of the isolates harboring KPC, NDM, and IMP genes. However, the assay failed to detect many GES- and OXA-48-like-positive isolates (65% positive results). In the second part of the study, a total of 314 blood cultures from patients were evaluated, and 33 yielded isolates resistant to meropenem (30 isolates were positive for carbapenemases according to PCR). The colorimetric tests correctly detected 24 out of the 30 carbapenemase-positive isolates directly from the blood vial (80% positive results). Overall positive percent agreement and negative percent agreement were 80% and 100%, respectively. The colorimetric assays are simple and cost-effective methods that can be implemented in a routine microbiology laboratory, diminishing the time necessary to detect carbapenemase-producing isolates from 24 to 48 h to 3 to 5 h. Moreover, according to our results, the positive colorimetric test results do not need to be confirmed and can be immediately provided to the attending physician.
本研究旨在评估两种快速比色法（CNPt-Direct 和 Blue-Carba），以在常规微生物实验室中直接从血培养物中检测产碳青霉烯酶。该方法最初在含有 61 株碳青霉烯酶阳性分离株的血培养物中进行了评估。然后，将其用于常规微生物实验室在 6 个月期间获得的血培养物（共评估了 314 个样本）。将比色法与常规血培养进行了比较。血培养物的结果表明，两种比色法均对携带 KPC、NDM 和 IMP 基因的绝大多数（95%）分离株呈阳性结果。然而，该检测未能检测到许多 GES-和 OXA-48 样阳性分离株（阳性结果为 65%）。在研究的第二部分，共评估了 314 例来自患者的血培养物，其中 33 例培养物产生了对美罗培南耐药的分离株（根据 PCR，30 株分离株对碳青霉烯酶呈阳性）。比色试验正确地从血瓶中直接检测到 30 株碳青霉烯酶阳性分离株中的 24 株（阳性结果为 80%）。总体阳性符合率和阴性符合率分别为 80%和 100%。比色试验是一种简单且经济有效的方法，可以在常规微生物实验室中实施，将检测产碳青霉烯酶分离株的时间从 24 小时减少到 48 小时，减少到 3 小时到 5 小时。此外，根据我们的结果，阳性比色试验结果无需确认，可立即提供给主治医生。
