APPARATUS AND METHOD FOR EXTRACTING MICROBIAL CELLS

摘要

Methods and devices are provided for pretreatment of a sample containing microbial cells. In some embodiments, the pretreatment of the sample is performed via the initial selective lysis, within a sample pretreatment vessel, of non-microbial cells (such as blood cells) and the subsequent centrifugal separation of the sample to remove the resulting debris and concentrate the microbial cells. An immiscible and dense cushioning liquid may be included for collecting the microbial cells adjacent to the liquid interface formed by the cushioning liquid upon centrifugation of the pretreatment vessel. After removal of a substantial quantity of the supernatant, resuspension of the collected microbial cells, and re-establishment of the cushioning liquid interface, at least a portion of the remaining suspension may be removed without substantially removing the cushioning liquid. One or more intermediate wash cycles may be performed prior to extraction of the remaining suspension, which provides a “pretreated” sample.

主权项

1. A method of extracting microbial cells from a blood containing sample, the method comprising:
adding a blood containing sample to a pretreatment vessel, the pretreatment vessel comprising a pretreatment mixture, the pretreatment mixture comprising a blood cell lysis reagent and a hydrophobic cushioning liquid having a density greater than that of the blood containing sample and the blood cell lysis reagent; agitating the contents of the pretreatment vessel; centrifuging the pretreatment vessel such that the cushioning liquid forms a liquid interface below a supernatant, wherein microbial cells from the blood containing sample are removed from suspension and collected adjacent to the liquid interface; withdrawing a substantial quantity of the supernatant without removing the collected microbial cells; agitating the contents of the pretreatment vessel and allowing the cushioning liquid to re-establish the liquid interface below a suspension containing the microbial cells; and extracting a least a portion of the suspension without extracting a substantial portion of the cushioning liquid, thereby obtaining an extracted suspension comprising microbial cells.