Device for detecting bacterial contamination and method of use

Abstract

A device and method for detecting the presence or absence of a prokaryotic microorganism are provided, comprising the steps of identifying a protein, such as a microbial-specific protease that characterizes the presence of a specific prokaryotic microbe and thereby provides a marker for that microbe; detecting the protease that is a marker for the presence of a specific prokaryotic microbe by cleaving a substrate when the protease is present; and signaling the presence of that protease when cleavage has occurred. More specifically, the method comprises identifying at least one outer membrane protein or a secreted protein that is unique to a particular microbial pathogen such as for example Listeria monocytogenes and that is substrate specific.

What is claimed is:  
     
         1 . A method for detecting the presence or absence of a prokaryotic microorganism in a sample, the method comprising the steps of: 
 a. identifying a protease that is unique to the prokaryotic microorganism;    b. providing a quenched labeled substrate specific for said protease; and    c. providing the sample; and    d. determining the presence or absence of a detectable label.    
     
     
         2 . The method of  claim 1  wherein the quenched label is selected from the group consisting of fluorescent labeled peptide and colorimetric labeled peptide.  
     
     
         3 . The method of  claim 2  wherein the means for determining is a colorimeter or fluorimeter.  
     
     
         4 . A method for detecting a plurality of pathogenic microorganisms in a sample, the method comprising the steps of: 
 a. identifying a protease that is unique to the prokaryotic microorganism;    b. providing a quenched labeled broad spectrum substrate for said protease;    c. providing the sample; and    d. determining the presence or absence of a detectable label.    
     
     
         5 . A method of using broad spectrum fluorescent or colorimetric labeled peptides to recognize a bacterial species by detecting the conjugated peptide with a colorimeter or fluorimeter.  
     
     
         6 . A device for capturing and releasing bacteria from solid or liquid extracts comprising protein encapsulated starch or Styrofoam.  
     
     
         7 . A device for capturing and releasing bacteria from a sample, said device comprising a pellet and a layer of antibodies entrapped in gelatin surrounding said pellet.  
     
     
         8 . A sensor for detection of bacteria in a sample, said device comprising packaging material having a first side proximal to said sample and having a second side; and a dye labeled substrate for the bacteria wherein said dye labeled substrate is attached to said first side.  
     
     
         9 . A method for using an alpha-crystallin type protein comprising the steps of: 
 (a) expressing and purifying the recombinant alpha-crystallin type protein; and    (b) adding the alpha-crystallin type protein to a solid phase or a liquid phase assay containing a dye labeled peptide in an amount sufficient to reduce proteolysis of said dye labeled peptide.