Wallis C, Melnick J L
J Clin Microbiol. 1985 Apr;21(4):505-8. doi: 10.1128/jcm.21.4.505-508.1985.
A semiautomated instrument (Septi-Screen) and method are described that semiquantify bacteria colorimetrically in blood-inoculated cultures in 2 to 8 h. If the blood culture is positive, concentrates (of viable bacteria) are obtained free of blood cells. In pediatric cases and in septicemia attributed to indwelling catheters where bacteremia is often manifested by high bacterial counts, the total time required to obtain bacterial concentrates is only 2 to 3 h. In brief, at various intervals after inoculation of 10 ml of blood into 100 ml of culture fluid, 25-ml blood culture samples are passed through the Septi-Filter. Erythrocytes and leukocytes pass into the filtrate and are discarded, but bacteria are electrostatically retained on the filter surface. The entrapped bacteria are backflushed and recovered as a concentrate that is processed through a second filter (Septi-Count) for colorimetric quantitation. The bacteria are stained, and the filter fibers are decolorized. The color intensity of the filter surface is proportional to the number of bacteria in the concentrate processed. The total Septi-Screen processing time is 3 to 5 min.
本文描述了一种半自动仪器（Septi-Screen）及其方法，该方法可在2至8小时内对血培养物中的细菌进行比色半定量。如果血培养呈阳性，则可获得不含血细胞的（活细菌）浓缩物。在儿科病例以及因留置导管导致的败血症中，菌血症通常表现为细菌数量较高，获得细菌浓缩物所需的总时间仅为2至3小时。简而言之，在将10毫升血液接种到100毫升培养液后的不同时间间隔，取25毫升血培养样本通过Septi-Filter。红细胞和白细胞进入滤液并被丢弃，但细菌通过静电作用保留在滤器表面。截留的细菌被反冲洗并作为浓缩物回收，然后通过第二个滤器（Septi-Count）进行比色定量。细菌被染色，滤器纤维被脱色。滤器表面的颜色强度与处理的浓缩物中细菌的数量成正比。Septi-Screen的总处理时间为3至5分钟。
