DISEASE CHARACTERISTICS:

• Histologically confirmed advanced and/or metastatic solid tumors refractory to standard curative or palliative therapy and for which no other conventional therapy exists
• Measurable or evaluable metastatic disease
• No brain metastases unless previously treated and no evidence of recurrence
• No lymphoma or other hematologic malignancy

PATIENT CHARACTERISTICS:

Age:

• 18 and over

Performance status:

• ECOG 0-1

Life expectancy:

• At least 3 months

Hematopoietic:

• Granulocyte count at least 2,000/mm^3
• Platelet count at least 100,000/mm^3
• Hematocrit at least 30% (transfusion allowed)
• No known bleeding disorder

Hepatic:

• Bilirubin no greater than 1.5 times upper limit of normal (ULN)
• ALT and AST no greater than 1.5 times ULN (3 times ULN if liver metastases present)
• Alkaline phosphatase no greater than 1.5 times ULN (3 times ULN if liver metastases present)
• PT and PTT no greater than 1.5 times ULN
• Hepatitis B surface antigen negative
• No chronic active hepatitis B
• No end-stage liver disease

Renal:

• Creatinine no greater than 2.0 mg/dL
• No urinary tract stones
• No end-stage renal disease

Cardiovascular:

• No known valvular disease
• No known clinically significant atherosclerotic disease, peripheral vascular disease, or arterial aneurysm
• No unstable angina
• No artificial heart valves

Pulmonary:

• No severe oxygen-dependent chronic obstructive pulmonary disease

Other:

• No artificial implant that cannot be removed (e.g., prosthetic hips or knees or other devices)
• No permanent central venous catheters
• No gallstones
• No active infection
• No documented Salmonella infection
• No tumor fever or fever of unknown origin or cause
• Daily maximum temperature no greater than 38.0 degrees Celsius
• HIV negative
• No documented immunodeficiency
• No other life-threatening illness
• No history of allergic reaction or hypersensitivity to quinolone or cephalosporin antibiotics
• No commercial food handlers, day-care workers, or health-care workers
• No patients unable to avoid close personal contact with severely immunosuppressed individuals (e.g., other patients on myelosuppressive cancer chemotherapy)
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• At least 4 weeks since prior biologic therapy and recovered

Chemotherapy:

• At least 4 weeks since prior cytotoxic chemotherapy (6 weeks for mitomycin or nitrosoureas) and recovered

Endocrine therapy:

• At least 2 weeks since prior hormonal therapy and recovered
• No concurrent steroids that could depress the immune system unless indicated for severe reactions

Radiotherapy:

• At least 4 weeks since prior radiotherapy and recovered

Surgery:

• At least 2 weeks since prior surgery and recovered
• No prior splenectomy
• No concurrent palliative surgery

Other:

• Recovered from any other prior anticancer therapies
• No concurrent antibiotics
• No concurrent immunosuppressives or any other medications that could suppress the immune system
• No other concurrent treatment for malignancy
• No requirement for immediate palliative treatment