Subjects are followed up 6 to 9 days after the last dose of study drug to assess clinical signs and symptoms of infection. A Late Follow Up evaluation (21 to 28 days after the last dose of study drug) occurs for those subjects who respond to therapy. The primary assessment of effectiveness is the microbiological response (the eradication at post-therapy of the infectious organism identified at the start of study). An additional assessment of efficacy includes the overall clinical response, which is described as cured, improved, or failed. Safety assessments include the incidence of adverse events throughout the study, clinical laboratory tests (hematology, serum chemistry, and urinalysis) and physical examinations at the start of the study and post-therapy.