Abstract: A process for determining one of the presence, absence, or total of microorganisms (e.g. bacteria) in a sample. According to the process, a biological sample containing complex matrices is obtained. The sample is first combined with a resin to adsorb complex matrices from the sample. The resin is removed from the biological sample. The sample so prepared is then analyzed by flow cytometry.

Abstract: Various embodiments disclosed herein provide for reagents and methods for rapidly isolating viable microbial cells, including S. pneumoniae, from positive blood culture samples. The resulting microbial pellet can be used for both identification and growth-based methods such as antimicrobial susceptibility testing. The buffers described herein may contain a base solution, non-ionic detergents, thiols, and optionally, ammonium chloride. The disclosed methods provide a process for rapidly isolating and concentrating viable microorganism (s) from PBC samples using only one sample preparation tube and centrifugation while removing cellular debris from the mammalian blood cells that may interfere with identification methods.

Abstract: Described herein are methods and reagents for identifying and analyzing at least one microorganism (e.g. bacteria) in a sample and reducing the background signal intensity obtained when analyzing the sample by flow cytometry. The sample is prepared by combining the sample with a background signal-reducing molecule or with a nucleic acid stain covalently linked to a quencher. A portion of the particulate matter in the sample can optionally be removed with a resin prior to staining with a nucleic acid stain.