PATIENT CHARACTERISTICS: Age: 18 and over Performance status: SWOG 0-2 Life expectancy: Not specified Hematopoietic: Not specified Hepatic: Not specified Renal: Not specified Other: Not pregnant or nursing Fertile patients must use effective contraception No other prior malignancy in the past 5 years except adequately treated basal cell or squamous cell skin cancer, carcinoma in situ of the cervix, or adequately treated stage I or II cancer in complete remission No allergies to fluoroquinolones If allergic to penicillin or cephalosporin, must be able to take co-trimoxazole