METHOD FOR DETECTING CONCENTRATIONS OF A TARGET BACTERIUM THAT USES PHAGES TO INFECT TARGET BACTERIAL CELLS

• US 20070275370A1
• Filed: 01/23/2007
• Published: 11/29/2007
• Est. Priority Date: 04/12/2002
• Status: Active Grant

• Current Assignee: Colorado School of Mines
• Original Assignee: Colorado School of Mines
• Inventors: Voorhees, Kent, Rees, Jon, Madonna, Angelo
• Granted Patent: US 7,972,773 B2
• Time in Patent Office: Days
• US Class Current: 435/5
• CPC Class Codes: C12Q 1/04 Determining presence or kind of microorganism; Use of selective media for testing antibiotics or bacteriocides; Compositions containing a chemical indicator therefor C12Q1/6897 takes precedence
• CPC Class Codes: G01N 33/54326 Magnetic particles
• CPC Class Codes: G01N 33/56911 Bacteria

Abstract

The invention is directed to a method for detecting low concentrations of bacteria in liquid solution that may or may not be complex liquid solutions. In one embodiment, immunomagnetic separation (IMS) is used to separate target bacterium that may be in a liquid mixture from other constituents in the mixture. A low concentration of a bacteriophage for the target bacteria is subsequently used to infect target bacterial cells that have been captured using the IMS technique. If at least a certain concentration of target bacterium are present, the bacteriophage will multiply to a point that is detectable. Matrix assisted laser desorption ionization/time-of-flight-mass spectrometry (MALDI/TOF-MS) is then used to produce a mass spectrum that is analyzed to determine if one or more proteins associated with the bacteriophage are present, thereby indirectly indicating that target bacterium were present in the liquid mixture.

Claims

1. A method for determining if a target bacterium is present in a liquid solution when the target bacterium is or may be present in a low concentration that is near or below the detection limit for a particular detection technology comprising:

making a determination as to whether a low concentration of a target bacterium may be present in a liquid solution;

using, following said step of making and if a determination is made that a low concentration of said target bacterium may be present, a first quantity of a bacteriophage to infect at least some of any target bacterium that are present in said liquid solution and multiply the number of bacteriophage in said liquid solution; and

analyzing, following said step of using, at least a portion of said liquid solution to determine if a biomarker for said bacteriophage is present that indirectly indicates that said target bacterium is also present in said liquid solution.

2-45. -45. (canceled)