This systematic review suggests it may not be warranted:
Based on all available data, antibiotic prophylaxis should not be used in patients with necrotizing pancreatitis. Instead, a more measured, on-demand use of antibiotics is preferred. Antibiotics should be added if signs and symptoms of infection are present (eg, fever, leukocytosis, positive results of cultures). Given improvements in intensive care and nutritional support, recent trials have found a lower incidence of infected necrotizing pancreatitis than before. Therefore, future trials are likely to need higher numbers of patients.