Detection of bacteria

• US 4,336,337 A
• Filed: 06/16/1980
• Issued: 06/22/1982
• Est. Priority Date: 09/25/1978
• Status: Expired due to Term

• Current Assignee: Baylor College of Medicine (Baylor College)
• Original Assignee: Baylor College of Medicine (Baylor College)
• Inventors: Wallis, Craig, Melnick, Joseph L.
• Primary Examiner(s): RICHMAN, BARRY
• Application Number:
  US06/159,785
• Time in Patent Office: 736 Days
• Field of Search: 422/55, 422/56, 422/57, 422/58, 422/69, 422/61, 23/230 B, 23/230 R, 435/30, 435/39, 435/40, 435/4, 435/29, 435/32, 435/33, 435/34, 435/36, 435/37, 435/243, 435/292, 435/293, 435/810, 435/38, 424/3, 424/7, 8/94.11
• US Class Current: 435/287.7
• 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: Y10S 435/81 Packaged device or kit

Abstract

A test substrate, including a semi-permeable membrane which retains bacteria on the membrane and which has a net positive surface charge to permit coloring of bacteria thereon with a cationic dye, without the membrane adsorbing substantial amounts of said dye. Substrate is included in a kit for detecting bacteria.

Claims

1. A kit for detecting bacteria, comprising:

(a) a cationic dye for staining bacteria at a pH of above 7.0;

(b) a chelating agent effective at a pH of above 7.0;

(c) an acid decolorizing wash at a pH of from 2.7 to 4.0; and

(d) a test substrate, said test substrate including a semi-permeable membrane which permits a test sample including bacteria to flow therethrough and which has a pore size to retain bacteria in the sample on the membrane for coloring thereon, said semi-permeable membrane having a net positive electrostatic surface charge to permit coloring of bacteria thereon with a cationic dye, without the membrane absorbing substantial amounts of said dye, the substrate including color differentiating indicia for providing a reading of bacterial concentration corresponding to color retained on the membrane.

2. The kit of claim 1 and further comprising a rust solvent for dissolving rust.

3. The kit of claim 1 wherein the test substrate is a card having an aperture, said semi-permeable membrane covering said aperture.

4. The kit of claim 3 wherein the semi-permeable membrane is essentially free of negative electrostatic surface charge.

5. The kit of claim 4 wherein the semi-permeable membrane is an epoxy-fiberglass membrane.

6. The kit of claim 4 wherein the dye is safranin-O.

7. The kit of claim 6 wherein the chelating agent is a salt of ethylenediaminetetraacetic acid.

8. The kit of claim 6 wherein the dye is chromatographically purified safranin-O dissolved in water.

9. The kit of claim 8 wherein the acid decolorizing wash is comprised of acetic acid.