If ascites or blood cultures grow specific bacterial pathogens, antibiotic therapy will be tailored to the narrowest spectrum antibiotic necessary for adequate coverage, based on in vitro organism susceptibilities. If any ascites is still present, all subjects will have a repeat diagnostic paracenteses at 48 hours after diagnosis for repeat of cell counts to assess for response to therapy. If ascites and blood cultures are negative, antibiotic coverage will be continued for a total of 5 days if clinical and laboratory resolution of the infection is verified. If subjects do not respond to initial therapy as measured by ascites PMN's not decreasing by 50% after the first 48 hours of treatment, the antibiotic regimen will be modified empirically by the primary medical team caring for the patient. Once resolution of the infection is established, after 5 days of initial therapy, all patients will be placed on ciprofloxacin, 750 mg once weekly for prophylaxis which will be continued indefinitely. If the patient is sensitive or allergic to fluoroquinolones, trimethoprim / sulfamethoxazole 160/800 mg once daily for 5 days a week will be used.