When Should a Patient with Ascites Receive Spontaneous Bacterial Peritonitis (SBP) Prophylaxis?

The Hospitalist. 2011 April;2011(04):

April 1, 2011 | The Hospitalist

Amira Del Pino Jones, MD ; University Of Colorado Denver

Though once-daily dosing of norfloxacin is recommended to decrease the promotion of resistant organisms in prophylaxis against SBP, ciprofloxacin once weekly is acceptable. In a group of patients with low ascitic protein content, with or without a history of SBP, weekly ciprofloxacin has been shown to decrease SBP incidence to 4% from 22% at six months.⁴ In regard to length of treatment, recommendations are to continue prophylactic antibiotics until resolution of ascites, the patient receives a transplant, or the patient passes away.¹

Table 1. Pathogenesis of Spontaneous Bacterial Peritonitis (SBP)

Intestinal hypomotility and immunodeficiency
Intestinal bacterial overgrowth and edema
Bacterial translocation
Bacteria enters mesenteric lymph nodes and bloodstream
Bacteria enters ascitic fluid

Source: Such J, Runyon BA. Spontaneous bacterial peritonitis. Clin Infect Dis. 1998;27(4):669-674.

Saab et al studied the impact of oral antibiotic prophylaxis in patients with advanced liver disease on morbidity and mortality.5 The authors examined prospective, randomized, controlled trials that compared high-risk cirrhotic patients receiving oral antibiotic prophylaxis for SBP with groups receiving placebo or no intervention. Eight studies totaling 647 patients were included in the analysis.

The overall mortality rate for patients treated with SBP prophylaxis was 16%, compared with 25% for the control group. Groups treated with prophylactic antibiotics also had a lower incidence of all infections (6.2% vs. 22.2% in the control groups). Additionally, a survival benefit was seen at three months in the group that received prophylactic antibiotics.

The absolute risk reduction with prophylactic antibiotics for primary prevention of SBP was 8% with a number needed to treat of 13. The incidence of gastrointestinal (GI) bleeding, renal failure, and hepatic failure did not significantly differ between treatment and control groups. Thus, survival benefit is thought to be related to the reduced incidence of infections in the group receiving prophylactic antibiotics.⁵

History of GI Bleeding

The incidence of developing SBP in cirrhotics with an active GI bleed is anywhere from 20% to 45%.^1,2 For those with ascites of any etiology and a GI bleed, the incidence can be as high as 60%.⁵ In general, bacterial infections are frequently diagnosed in patients with cirrhosis and GI bleeding, and have been documented in 22% of these patients within the first 48 hours after admission. According to several studies, that percentage can reach as high as 35% to 66% within seven to 14 days of admission.⁶ A seven-day course of antibiotics, or antibiotics until discharge, is generally acceptable for SBP prophylaxis in the setting of ascites and GI bleeding (see Table 2, right).¹

Table 2. American Association for the Study of Liver Diseases Recommendations for Spontaneous Bacterial Peritonitis (SBP) Prophylaxis in Patients With Ascites and Cirrhosis*

Patients with gastrointestinal (GI) bleed: Intravenous (IV) ceftriaxone for seven days or twice-daily norfloxacin for seven days.
Patients with history of SBP: Long-term prophylaxis with daily norfloxacin or trimethoprim/sulfamethoxazole.
Patients with ascitic fluid protein < 1.5 g/dL and at least one of the following: serum creatinine > 1.2 mg/dL, blood urea nitrogen > 25 mg/dL, serum sodium < 130 meq/L, or Child-Pugh > 9 points with bilirubin >3 mg/dL.

*Due to development of bacterial resistance, intermittent dosing of antibiotics may be inferior to daily dosing. Thus, daily dosing should be used, when possible.

Source: Adapted from Runyon, BA. Management of adult patients with ascites due to cirrhosis: an update. Hepatology. 2009;49(6):2087-2107.

Bernard et al performed a meta-analysis of five trials to assess the efficacy of antibiotic prophylaxis in the prevention of infections and effect on survival in patients with cirrhosis and GI bleeding. Out of 534 patients, 264 were treated with antibiotics between four and 10 days, and 270 did not receive any antibiotics.