Direct susceptibility testing of positive blood cultures by using sensititre broth microdilution plates
Direct susceptibility testing of positive blood cultures by using sensititre broth microdilution plates
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DOI：
10.1128/jcm.41.10.4751-4754.2003
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发表时间：
2003-10-01
影响因子：
9.4
通讯作者：
Musgnug, MC
中科院分区：
文献类型：
--
作者：
Chapin, KC;Musgnug, MC
传统的血培养物药敏试验需要过夜孵育才能获得分离的菌落。通过使用血培养液中的细菌沉淀，可以提前 24 小时报告药敏结果。本研究评估了使用 Sensititre 肉汤微量稀释板对阳性 ESP 血培养肉汤进行直接药敏测试的准确性，并与使用分离菌落进行测试进行比较。实用的纳入标准适用于革兰氏阳性生物体，以避免报告可能污染物的敏感性。所有革兰氏阴性生物体均直接进行测试。将等份血培养物离心，所得沉淀用于制备 0.5 McFarland 悬浮液。根据制造商的说明对微量稀释板进行接种和解释。进行菌落计数以确保达到适当的菌落密度。总共评估了 199 名患者和种子血培养物的基本一致性（在 +/-1 倍稀释度范围内）和分类一致性（敏感、中等或耐药）。对 93 种革兰氏阳性分离株（1,214 种抗菌药物-生物体组合）的测试得出了 98% 的基本一致性，分类错误率为 0.3% 轻微错误、无重大错误（假耐药）和 1.7% 非常重大错误（假敏感性）。对于 106 种革兰氏阴性分离株（1,828 种抗菌剂-生物体组合），基本一致性为 99%。次要错误、重大错误和非常重大错误的分类错误率分别为 0.5%、0% 和 2.0%。革兰氏阳性和革兰氏阴性分离株以及需氧和厌氧培养基的性能相当。使用这种直接测试方法，可以提前 24 小时向医生报告可靠的药敏结果，从而可以更早地适当修改抗菌治疗。
Traditional susceptibility testing of blood cultures requires overnight incubation in order to obtain isolated colonies. Susceptibility results can be reported up to 24 h sooner by using a bacterial pellet from the blood culture broth. This study evaluated the accuracy of direct susceptibility testing from positive ESP blood culture broths by using Sensititre broth microdilution plates compared to testing with isolated colonies. Practical inclusion criteria were applied to gram-positive organisms to avoid reporting susceptibilities for probable contaminants. All gram-negative organisms were tested directly. An aliquot of the blood culture was centrifuged, and the resulting pellet was used to make a 0.5 McFarland suspension. Microdillution plates were inoculated and interpreted according to the manufacturer's instructions. Colony counts were performed to ensure proper colony density was achieved. A total of 199 patient and seeded blood cultures were evaluated for both essential (within +/-1 twofold dilution) and categorical (sensitive, intermediate, or resistant) agreement. Testing of 93 gram-positive isolates (1,214 antimicrobial agent-organism combinations) yielded 98% essential agreement and categorical error rates of 0.3% minor, no major (false resistance), and 1.7% very major (false susceptibility) errors. For 106 gram-negative isolates (1,828 antimicrobial agent-organism combinations), the essential agreement was 99%. Categorical error rates were 0.5, 0, and 2.0% for minor, major, and very major errors, respectively. Performance was comparable for both gram-positive and gram-negative isolates, as well as for both aerobic and anaerobic media. Using this direct testing methodology, reliable susceptibility results can be reported to physicians 24 h sooner, allowing earlier appropriate modification of antimicrobial therapy.