Synthetic bacteriophages and bacteriophage compositions

1. A method of screening synthetic bacteriophages for ability to infect bacterial cells, comprising:

(a) exposing bacterial cells to a plurality of synthetic bacteriophages, wherein each synthetic bacteriophage in the plurality comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein; and

(b) identifying synthetic bacteriophages that are capable of sustaining infection of the bacterial cells to an extent that exceeds that of a corresponding bacteriophage that does not contain the mutations in the one or more binding loops of the tail fiber tip protein.

2. The method of claim 1 , wherein the bacterial cells are E. coli cells.

3. The method of claim 1 , wherein the bacterial cells are ΔwaaG mutants or ΔwaaC mutants.

4. A method of generating a population of synthetic bacteriophages that targets a bacterial strain and the bacteriophage-resistant variants thereof, the method comprising:

(a) exposing a first population of bacterial cells to a first plurality of synthetic bacteriophages, wherein each synthetic bacteriophage in the first plurality comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein;

(b) identifying synthetic bacteriophages that are capable of sustaining infection of the bacterial cells of the first population;

(c) exposing a second population of bacterial cells to the synthetic bacteriophages identified in (b) until such time that bacteriophage-resistant variants arise, wherein the bacterial cells of the second population are the same strain as the bacterial cells of the first population;

(d) exposing the bacteriophage-resistant variants of (c) to a second plurality of synthetic bacteriophages, wherein each synthetic bacteriophage in the second plurality comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein;

(e) identifying the synthetic bacteriophages that are capable of infecting the bacteriophage-resistant variants; and

(f) combining the synthetic bacteriophages identified to produce a population of synthetic bacteriophages that targets the strain of the first and second population of bacterial cells and the bacteriophage-resistant variants thereof.

5. The method of claim 4 , wherein the steps are iteratively repeated to identify additional synthetic bacteriophage that are capable of infecting additional bacteriophage-resistant variants.

6. A method of delaying the evolution of a bacterial strain comprising exposing the bacterial strain to a population of synthetic bacteriophages generated as in claim 4 or to a composition comprising said population of synthetic bacteriophages.

7. A method for suppressing resistance of a bacterial strain to bacteriophage infection comprising contacting a population of bacterial cells with a plurality of synthetic bacteriophages or with a composition comprising said population of synthetic bacteriophages, wherein the plurality of synthetic bacteriophages comprises:

a first synthetic bacteriophage having a first host range, and

a second synthetic bacteriophage having a second host range;

wherein the first and the second host ranges are distinct; and

wherein the first synthetic bacteriophage and/or the second synthetic bacteriophage comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein.

8. The method of claim 7 , wherein the step of contacting the population of bacterial cells with the population of synthetic bacteriophages or the composition comprising said population of synthetic bacteriophages comprises administering the population of synthetic bacteriophages or the composition comprising said population of synthetic bacteriophages to a subject.

9. The method of claim 7 , wherein the step of contacting the population of bacterial cells with the population of synthetic bacteriophages or the composition comprising said population of synthetic bacteriophages comprises contacting an isolated population of bacterial cells with the population of synthetic bacteriophages or with the composition comprising said population of synthetic bacteriophages.

10. The method of claim 7 , wherein the population of synthetic bacteriophages is generated by a method comprising:

(a) exposing a first population of bacterial cells to a first plurality of synthetic bacteriophages, wherein each synthetic bacteriophage comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein;

(b) identifying synthetic bacteriophages that are capable of sustaining infection of the bacterial cells of the first population;

(c) exposing a second population of bacterial cells to the synthetic bacteriophages identified in (b) until such time that bacteriophage-resistant variants arise, wherein the bacterial cells of the second population are the same strain as the bacterial cells of the first population; and

(d) exposing the bacteriophage-resistant variants of (c) to a second plurality of synthetic bacteriophages, wherein each synthetic bacteriophage comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein.

11. A method for preparing a cocktail of synthetic bacteriophages comprising:

(a) obtaining a sample from a patient, wherein the sample comprises bacterial cells;

(b) contacting the bacterial cells with a library of synthetic bacteriophages; and

(c) identifying synthetic bacteriophages that infect the bacterial cells; and

(d) combining the identified synthetic bacteriophages to produce a cocktail of synthetic bacteriophages.

12. The method of claim 11 , wherein more than one sample is obtained from a patient at different times.

13. The method of claim 11 , wherein the cocktail of synthetic bacteriophages comprises a bacteriophage comprising mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein.

14. The method of claim 11 , wherein each of the synthetic bacteriophages in the cocktail comprises mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein.

15. A method for identifying bacterial cells or diagnosing bacterial infections comprising:

(a) contacting a sample containing bacterial cells with a synthetic bacteriophage comprising mutations in a tail fiber tip protein, wherein the mutations: (i) are engineered in one or more binding loops of the tail fiber tip protein, wherein the binding loops face the basal or apex side of the tail fiber; and (ii) cause the synthetic bacteriophage to have a different host range than the corresponding bacteriophage lacking the mutations in the tail fiber tip protein;

(b) incubating the sample containing the bacterial cells with the synthetic bacteriophage for a time sufficient for the synthetic bacteriophage to infect the bacterial cells; and

(c) detecting the synthetic bacteriophage and/or bacterial cell lysis to identify the bacteria or to diagnose bacterial infection.

16. The method of claim 15 , wherein the sample is obtained from a patient.