Methods for isolating phage and for controlling microorganism populations with the phage
A lytic virus specific for a target strain of a microorganism and substantially free of undesirable genes may be utilized in processes including control of populations of microorganisms. The virus may include a host-range mutant, or “h-mutant.” A method for generating virus includes growing virus-resistant variants of a target strain of a microorganism in the presence of viruses that are specific for the target strain. Only h-mutant viruses will proliferate. Wild-type virus-resistant and virus-resistant variants of a microorganism are also disclosed, as are methods generating such variants. Methods for controlling target strain microorganisms include introducing virus into a treatment site where control of a population of a target strain microorganism is desired or introducing virus-resistant variants of a microorganism into treatment sites where the presence of the microorganism is desired.
1. A method of controlling a population of a target strain of a microorganism on a food, comprising:
introducing a virus composition into contact with a food that has been at least partially prepared for consumption, the food possibly contaminated with a target strain of a host microorganism,
the target strain of the host microorganism comprising a microorganism that causes a disease state in humans or animals or a microorganism that causes food to spoil,
the virus composition comprising variant virus particles, the variant virus particles having an expanded host range over a wild-type virus particle, the expanded host range including:
a wild-type of the target strain of the host microorganism; and
at least one virus-resistant variation of the target strain of the host microorganism that resists infection by the wild-type virus particle; and
permitting the variant virus particles to bind to and infect:
the wild-type of the target strain of the host microorganism; and
the at least one virus-resistant variation of the target strain of the host microorganism
to limit growth of a population of the wild-type of the target strain of the host microorganism and the at least one virus-resistant variation of the target strain of the host microorganism.
2. The method according to claim 1 , wherein introducing the virus composition comprises introducing the virus composition in which the variant virus particles are lytic virus particles.
3. The method according to claim 1 , wherein introducing the virus composition comprises introducing the virus composition including wild-type virus particles into contact with the food.
4. The method according to claim 1 , further comprising:
introducing an antimicrobial agent into a treatment site at which the food is present.
5. The method according to claim 1 , wherein introducing the virus composition comprises introducing the virus composition into contact with raw meat or raw poultry.
6. The method according to claim 1 , wherein introducing the virus composition comprises introducing the virus composition in which variant virus particles are selective for the target strain microorganism over a beneficial microorganism.
7. The method according to claim 1 , wherein introducing comprises introducing the virus composition into contact a food possibly contaminated with E. coli 0157:H7.
8. A method for disinfecting a food at least partially prepared for a human or an animal to consume, comprising:
applying a virus composition to a food at least partially prepared for consumption by a human or an animal, the virus composition comprising variant virus particles:
being specific for a target strain of a host microorganism comprising a microorganism that causes a disease state in the human or the animal or a microorganism that causes food to spoil; and
having an expanded host range over a wild-type virus particle, the expanded host range of the variant virus particles including:
a wild-type of the target strain of the host microorganism; and
at least one virus-resistant variation of the target strain of the host microorganism that resists infection by the wild-type virus particle; and
permitting the variant virus particles to bind to and infect:
the wild-type of the target strain of the host microorganism; and
the at least one virus-resistant variation of the target strain of the host microorganism
to limit growth of a population of the target strain of the host microorganism, including the wild-type of the target strain and the at least one virus-resistant variation of the target strain.
9. The method according to claim 8 , wherein applying comprises applying the virus composition to a food comprising at least one of raw meat and raw poultry.
10. A method for disinfecting meat or poultry to be consumed by a human or an animal, comprising:
applying a virus composition to meat or poultry to be consumed by a human or an animal, the virus composition comprising variant virus particles:
being specific for a target strain of a host microorganism comprising a microorganism that causes a disease state in the human or the animal or a microorganism that causes food to spoil; and
being selected for an inability to transfer undesired genes to the target strain of the host microorganism upon infecting the target strain of the host microorganism; and
having an expanded host range over a wild-type virus particle, the expanded host range including:
a wild-type of the target strain of the host microorganism; and
at least one virus-resistant variation of the target strain of the host microorganism that resists infection by the wild-type virus particle; and
permitting the variant virus particles to bind to and infect:
the wild-type of the target strain of the host microorganism; and
the at least one virus-resistant variation of the target strain of the host microorganism
to limit growth of a population of the wild-type of the target strain of the host microorganism and the at least one virus-resistant variation of the target strain of the host microorganism.
11. The method according to claim 10 , wherein applying comprises applying the virus composition to the meat or poultry to kill, prevent growth of or prevent proliferation of the target strain of a host microorganism comprising a bacteria from at least one of the Salmonella genus, the Campylobacter genus, and the Escherichia genus.
12. The method according to claim 10 , wherein applying comprises applying the virus composition to the meat or poultry to kill, prevent growth of or prevent proliferation of the target strain of a host microorganism comprising E. coli 0157:H7.
13. The method according to claim 10 , wherein applying comprises applying the virus composition to raw meat or raw poultry.
14. The method according to claim 8 , wherein applying comprises applying the virus composition to the food to kill, prevent growth of or prevent proliferation of the target strain of a host microorganism comprising a bacteria from at least one of the Salmonella genus, the Campylobacter genus, and the Escherichia genus.
15. The method according to claim 8 , wherein applying comprises applying the virus composition to the food to kill, prevent growth of or prevent proliferation of the target strain of a host microorganism comprising E. coli 0157:H7.