The purpose of this study is to evaluate the effects of Delafloxacin versus Vancomycin plus Aztreonam in the treatment of patients with acute bacterial skin and soft tissue infections.

The purpose of this study is to determine if delafloxacin, an investigational drug, is safe and effective in the treatment of skin and nearby tissue infections compared with a combination of other antibiotics, vancomycin and aztreonam.

Inclusion Criteria:

• Adult (≥ 18 years of age) men or women with a diagnosis of ABSSSI (cellulitis/erysipelas, wound infection, major cutaneous abscess, or burn infection) with surrounding redness of a minimum surface area of 75 cm^2 and at least two signs of systemic infection
• In the opinion of the investigator, the subject must require and be a suitable candidate for IV antibiotic therapy, and the subject must be able and willing to comply with protocol requirements

Exclusion Criteria:

• A medical history of significant hypersensitivity or allergic reaction to quinolones, beta-lactams, vancomycin, or vancomycin derivatives according to the judgment of the investigator.

• Women who are pregnant or lactating.

• Any chronic or underlying skin condition at the site of infection that may complicate the assessment of response, including infection involving a prosthetic joint, human or animal bite, osteomyelitis, decubitus ulcer, diabetic foot ulcer, septic arthritis, mediastinitis, necrotizing fasciitis, anaerobic cellulitis, or synergistic necrotizing cellulitis, myositis, tendinitis, endocarditis, sustained shock, gangrene or gas gangrene; burns covering ≥10% of body surface area; severely compromised immune system, severely impaired arterial blood supply to an extremity with an ABSSSI, deep vein thrombosis or superficial thrombophlebitis, and requiring either an amputation or multiple debridement procedures.

• Receipt of systemic antibiotic therapy in the 14 days before enrollment unless 1 of the following was documented:

  • Received ≥ 48 hours of antibiotic therapy for ABSSSI AND clinical progression is documented (i.e., not by patient history alone).
  • Recently (within 14 days) completed a treatment course with an antibacterial drug for an infection other than ABSSSI and the drug does not have activity against bacterial pathogens that cause ABSSSI.
  • Received only 1 dose of either a single, potentially effective, short-acting antimicrobial drug or drug regimen for ABSSSI.

• Any underlying disease that, in the opinion of the investigator, could interfere with the subject's ability to participate in the study including severe cardiac disease, known history of liver disease, end-stage renal disease, malignancy, psychiatric disorder, ongoing treatment for seizures or untreated history of seizures, or life expectancy of < 3 months.