• Clinical response rate (reduction in signs and symptoms) at post-therapy (5 - 7 days after the last dose of study drug)
  

• Rate of elimination of disease-causing bacteria, by patient, and by type of bacteria; incidence of adverse events; changes in physical examination and laboratory tests after the last dose of study drug
  

This is a randomized, open-label, parallel group, multicenter study to determine the safety and effectiveness of 500 mg of levofloxacin (once daily for 5 - 7 days) compared with 250 mg of cefuroxime axetil (every 12 hours for 10 days) in adults with chronic bronchitis experiencing rapid onset of severe worsening of symptoms caused by bacteria. The study consists of 3 visits: one visit for screening and enrollment, and 2 visits for assessment of safety and effectiveness (one visit on Days 3 - 5 of the study and one visit [post-therapy] 5 - 7 days after the last dose of the study drug). The total duration of patient participation in the study is approximately 2 weeks. The primary efficacy assessment is the clinical response 5 - 7 days after the last dose of study drug, (categorized as cured, improved, or failed) based upon changes in signs and symptoms. Safety evaluations (incidence of adverse events, physical examination, laboratory tests) are performed throughout the study. The study hypothesis is that treatment with levofloxacin is at least as effective and as well tolerated as treatment with cefuroxime axetil in adult patients with chronic bronchitis experiencing sudden worsening of symptoms caused by bacterial infection. Levofloxacin 500 mg by mouth once daily for 5 - 7 days, or cefuroxime axetil 250 mg by mouth every 12 hours for 10 days