Method for preventing or treating nosocomial pneumonia

1. A method of treating a Pseudomonas aeruginosa infection in a susceptible human subject comprising administering to the subject 1500 mg or 3000 mg of a bispecific antibody that specifically binds Pseudomonas aeruginosa Psl and PcrV,

wherein the bispecific antibody comprises a binding domain which specifically binds to P. aeruginosa Psl comprising a set of complementarity determining regions (CDRs): HCDR1-Psl, HCDR2-Psl, HCDR3-Psl, LCDR1-Psl, LCDR2-Psl, and LCDR3-Psl, wherein HCDR1-Psl has the amino acid sequence of SEQ ID NO: 10, HCDR2-Psl has the amino acid sequence of SEQ ID NO: 11, HCDR3-Psl has the amino acid sequence of SEQ ID NO: 12, LCDR1-Psl has the amino acid sequence of SEQ ID NO: 13, LCDR2-Psl has the amino acid sequence of SEQ ID NO: 14, and LCDR3-Psl has the amino acid sequence of SEQ ID NO: 15; and a binding domain which specifically binds to P. aeruginosa PcrV comprising a set of CDRs: HCDR1-PcrV, HCDR2-PcrV, HCDR3-PcrV, LCDR1-PcrV, LCDR2-PcrV, and LCDR3-PcrV, wherein HCDR1-PcrV has the amino acid sequence of SEQ ID NO: 2, HCDR2-PcrV has the amino acid sequence of SEQ ID NO: 3, HCDR3-PcrV has the amino acid sequence of SEQ ID NO: 4, LCDR1-PcrV has the amino acid sequence of SEQ ID NO: 6, LCDR2-PcrV has the amino acid sequence of SEQ ID NO: 7, and LCDR3-PcrV has the amino acid sequence of SEQ ID NO: 8, and

wherein the subject maintains a serum concentration of the bispecific antibody of at least 1.7 μg/mL through 7 days following administration of the bispecific antibody.

2. The method of claim 1 , wherein the infection is pneumonia, bacteremia, bone infection, joint infection, skin infection, burn infection, wound infection, or any combination thereof.

3. The method of claim 2 , wherein the infection is pneumonia.

4. The method of claim 1 , wherein the subject maintains a serum concentration of the bispecific antibody of at least 1.7 μg/mL through 21 days following administration of the bispecific antibody.

5. The method of claim 1 , wherein the binding domain which specifically binds to P. aeruginosa Psl comprises an scFv comprising the amino acid sequence of SEQ ID NO:9.

6. The method of claim 1 , wherein the binding domain which specifically binds to P. aeruginosa PcrV comprises a variable heavy chain comprising the amino acid sequence of SEQ ID NO:1 and a variable light chain comprising the amino acid sequence of SEQ ID NO:5.

7. The method of claim 1 , wherein the bispecific antibody comprises

(i) a heavy chain of the formula VH-CH1-H1-L1-S-L2-H2-CH2-CH3, wherein VH is an anti- P. aeruginosa PcrV heavy chain variable domain comprising the amino acid sequence of SEQ ID NO: 1; CH1 is a heavy chain constant region domain 1; H1 is a first heavy chain hinge region fragment; L1 is a first linker; S is an anti- P. aeruginosa Psl ScFv molecule comprising the amino acid sequence of SEQ ID NO: 9; L2 is a second linker; H2 is a second heavy chain hinge region fragment; CH2 is a heavy chain constant region domain-2; and CH3 is a heavy chain constant region domain-3; and

(ii) a light chain of the formula VL-CL, wherein VL is an anti- P. aeruginosa PcrV light chain variable domain comprising the amino acid sequence of SEQ ID NO: 5, and CL is an antibody light chain kappa constant region or an antibody light chain lambda region.

8. The method of claim 1 wherein the infection is a nosocomial infection.