Provided herein are methods for treating planktonic bacteria or a biofilm. The methods include contacting the planktonic bacteria or biofilm with an effective amount of an isolated Citrobacter freundii colicin A polypeptide, wherein the polypeptide has an antibacterial activity against the planktonic bacteria or the biofilm. Methods are also provided herein for treating a subject that has a bacterial infection, for example caused by a biofilm. The methods can be used to treat a biofilm on a living or non-living surface. Also provided herein are Citrobacter freundii colicin A polypeptides that have an antibacterial activity against planktonic bacteria or surface attached bacteria, and nucleic acid sequences encoding the polypeptides. Medical devices comprising a surface having an antimicrobial effective amount of a Citrobacter freundii colicin A polypeptide, or a nucleic acid molecule encoding the polypeptide, are also disclosed.
1. An isolated polypeptide, comprising the amino acid sequence set forth as SEQ ID NO: 1, wherein the polypeptide has an antibacterial activity against a biofilm.
2. A composition comprising the polypeptide of claim 1 .
3. The composition of claim 2 , further comprising one or more compounds selected from the group consisting of a carrier, diluent, adjuvant, solubilizing agent, and suspending agent.
4. The composition of claim 2 , further comprising a second antibacterial agent, an antifungal agent, or an antiprotozoal agent.
5. A pharmaceutical composition, comprising the polypeptide of claim 1 and a pharmaceutical carrier.
6. A medical device comprising a surface, wherein the surface comprises an antimicrobial effective amount of the polypeptide of claim 1 .
7. The medical device of claim 6 , wherein the polypeptide is incorporated into a polymeric coating on the medical device surface.
8. A method for treating a biofilm, comprising contacting the biofilm with an effective amount of an antibacterial agent, wherein the agent comprises the isolated polypeptide of claim 1 and wherein the isolated polypeptide has an antibacterial activity against the biofilm, thereby treating the biofilm.
9. The method of claim 1 , further comprising selecting for treatment a surface infected with a biofilm.
10. The method of claim 1 , wherein the biofilm is on a medical device suitable for surgical implantation within the body.
11. The method of claim 10 , wherein the medical device is a catheter, a stent, a shunt, an endotracheal tube, a gastric feeding tube, a prosthetic joint, an intrauterine device, a voice prosthesis, a central venous catheter, a tympanostomy tube, a prosthetic heart valve, or a pacemaker.
12. The method of claim 1 , wherein treating the biofilm reduces biofilm cell viability by at least 2%, at least 5%, at least 10%, at least 20%, at least 25%, at least 50%, at least 75%, at least 80%, at least 90%, at least 95%, at least 99%, or 100%.
13. The method of claim 1 , wherein the biofilm comprises Gram-negative bacteria.
14. The method of claim 13 , wherein the Gram-negative bacteria comprise the family Enterobacteriacae.
15. The method of claim 14 , wherein the Enterobacteriacae bacteria comprise a genus selected from the group consisting of Citrobacter, Enterobacter, Escherichia, Klebsiella , and Yersinia.
16. The method of claim 12 , further comprising one or more additional administrations of the isolated polypeptide to inhibit growth of the biofilm.
17. The method of claim 1 , further comprising contacting the biofilm with an effective amount of a second antibacterial agent.
18. The method of claim 1 , further comprising contacting the biofilm with an effective amount of an antifungal agent or an antiprotozoal agent.
19. A method for treating a subject infected with a biofilm, comprising: administering to the subject a therapeutically effective amount of a pharmaceutical composition comprising an antibacterial agent, wherein the antibacterial agent comprises the isolated polypeptide of claim 1 and wherein the isolated polypeptide has an antibacterial activity against the biofilm, thereby treating the subject.
20. The method of claim 19 , wherein the biofilm is on a medical device implanted in the subject.
21. The method of claim 20 , wherein the medical device is a catheter, a stent, a shunt, an endotracheal tube, a gastric feeding tube, a prosthetic joint, an intrauterine device, a voice prosthesis, a central venous catheter, a tympanostomy tube, a prosthetic heart valve, or a pacemaker.
22. The method of claim 19 , wherein treating the subject reduces biofilm cell viability by at least 2%, at least 5%, at least 10%, at least 20%, at least 25%, at least 50%, at least 75%, at least 80%, at least 90%, at least 95%, at least 99%, or 100%.
23. The method of claim 22 , further comprising one or more additional administrations of the pharmaceutical composition to the subject to inhibit further growth of the bacterial biofilm.
24. The method of claim 19 , wherein the biofilm comprises Gram-negative bacteria.
25. The method of claim 24 , wherein the Gram-negative bacteria comprise the family Enterobacteriacae.
26. The method of claim 25 , wherein the bacteria comprises a genus selected from the group consisting of Citrobacter, Enterobacter, Escherichia, Klebsiella , and Yersinia.
27. The method of claim 19 , further comprising administering to the subject a therapeutically effective amount of a second antibacterial agent.
28. The method of claim 19 , further comprising administering to the subject a therapeutically effective amount of an antifungal agent or an antiprotozoal agent.