Phage constructs for detecting bacteria in a fluid, microfluidic devices for use with constructs, and related methods

A method of detecting bacteria, the method comprising:

• providing a sample including bacteria;
• isolating the bacteria;
• incubating the bacteria for a first incubation period;
• adding a bacteriophage to the bacteria, the bacteriophage including an expression construct that encodes a fusion protein;
• incubating the bacteria for a second incubation period sufficient for the bacteriophage to infect the bacteria and the bacteria to express the fusion protein;
• capturing the fusion protein;
• and
• detecting the bacteria by detecting the fusion protein.

A method of immobilizing bacterial products for detection, the method comprising:

• exposing a bacteriophage including an expression construct to bacteria, wherein the expression construct includes a reporter enzyme and a protein affinity tag;
• incubating the bacteriophage and the bacteria for an incubation time sufficient for the bacteriophage to infect the bacteria and the bacteria to produce the reporter enzyme and the protein affinity tag as a fusion protein;
• immobilizing the fusion protein by binding the protein affinity tag to a complementary substrate;
• and
• detecting the bacteria by detecting the reporter enzyme of the fusion protein.

An expression construct, comprising:

• a phage-specific promoter;
• a reporter enzyme gene operably linked to the promoter, the reporter enzyme gene selected from alkaline phosphatase, β-galactosidase, β-glucuronidase, green fluorescent protein, luciferase, neuraminidase, and a derivative of any of the foregoing;
• and
• at least a portion of a protein affinity tag gene downstream of the reporter enzyme gene and operably linked to the promoter, the protein affinity tag gene selected from a carbohydrate binding module, a chitin binding protein, glutathione-S-transferase, a His tag, a maltose binding protein, and a Strep-tag.