Sequence specific antimicrobials
Provided are compositions and methods for selectively reducing the amount of antibiotic resistant and/or virulent bacteria in a mixed bacteria population, or for reducing any other type of unwanted bacteria in a mixed bacteria population. The compositions and methods involve targeting bacteria that are differentiated from other members of the population by at least one unique clustered regularly interspaced short palindromic repeats (CRISPR) targeted DNA sequence. The compositions and methods can be readily adapted to target any bacteria or any bacteria plasmid, or both.
1. A pharmaceutical composition for killing targeted bacteria in a mixed bacterial population comprising:
a pharmaceutically acceptable carrier and
a packaged, recombinant phagemid that is packaged in a phage capsid,
wherein the packaged phagemid comprises a clustered regularly interspaced short palindromic repeats (CRISPR) system,
wherein the CRISPR system comprises DNA encoding: i) a type II CRISPR-associated enzyme; and ii) a targeting RNA that targets at least one bacterial chromosome at a target site; and
wherein, upon contacting a bacterial population containing the at least one bacterial chromosome with the pharmaceutical composition, the phagemid is introduced into bacteria in the bacterial population,
wherein subsequent to the introduction of the phagemid, the targeting RNA and the type II CRISPR-associated enzyme are expressed in the bacteria into which the phagemid is introduced,
wherein the expressed type II CRISPR-associated enzyme cleaves the bacterial chromosome at the target site of the targeting RNA, and
wherein the cleavage of the bacterial chromosome at the target site kills the bacteria.
2. The pharmaceutical composition of claim 1 , wherein the type II CRISPR-associated enzyme is a Cas9 enzyme.
3. The pharmaceutical composition of claim 2 , wherein the Cas9 enzyme is a Streptococcus pyogenes Cas9.
4. The pharmaceutical composition of claim 1 , further comprising detecting the killing of bacteria by the pharmaceutical composition.
5. The pharmaceutical composition of claim 1 , wherein the bacteria is selected from the group consisting of Staphylococcus, Clostridium, Bacillus, Salmonella, Helicobacter pylori, Neisseria gonorrhoeae, Neisseria meningitidis , and Escherichia coli.
6. The pharmaceutical composition of claim 5 , wherein the bacteria is Staphylococcus aureus.
7. The pharmaceutical composition of claim 6 , wherein the bacteria is a methicillin-resistant Staphylococcus aureus.
8. A pharmaceutical composition for killing targeted bacteria in a mixed bacterial population comprising:
a pharmaceutically acceptable carrier and
a packaged, recombinant phagemid that is packaged in a phage capsid,
wherein the packaged phagemid comprises a clustered regularly interspaced short palindromic repeats (CRISPR) system,
wherein the CRISPR system comprises DNA encoding: i) a type II CRISPR-associated enzyme; and ii) a targeting RNA that targets an antibiotic resistance gene on a plasmid at a target site within the plasmid;
wherein, upon contacting a bacterial population containing the at least one antibiotic resistance gene on a plasmid with the pharmaceutical composition, the phagemid is introduced into bacteria in the bacterial population,
wherein the targeting RNA and the type II CRISPR-associated enzyme are expressed in the bacteria into which the phagemid is introduced,
wherein the expressed type II CRISPR-associated enzyme cleaves the antibiotic resistance gene on a plasmid at the target site within the plasmid, and
wherein the cleavage of the bacterial plasmid at the target site kills the bacteria in the presence of the antibiotic.
9. The pharmaceutical composition of claim 8 , wherein the type II CRISPR-associated enzyme is a Cas9 enzyme.
10. The pharmaceutical composition of claim 9 , wherein the Cas9 enzyme is a Streptococcus pyogenes Cas9.
11. The pharmaceutical composition of claim 8 , further comprising detecting the killing of bacteria by the pharmaceutical composition.
12. The pharmaceutical composition of claim 8 , wherein the bacteria is selected from the group consisting of Staphylococcus, Clostridium, Bacillus, Salmonella, Helicobacter pylori, Neisseria gonorrhoeae, Neisseria meningitidis , and Escherichia coli.
13. The pharmaceutical composition of claim 12 , wherein the bacteria is Staphylococcus aureus.
14. The pharmaceutical composition of claim 13 , wherein the bacteria is a methicillin-resistant Staphylococcus aureus.