*6.1.2.1 Infected necrosis*

Infection should be suspected in patients with pancreatic or extrapancreatic necrosis upon clinical deterioration or a lack of improvement within 7–10 days of hospitalization. Infectious agents are usually of intestinal origin (such as Escherichia coli, Pseudomonas, Klebsiella and Enterococcus), and may be suspected with the emergence of clinical signs of infection in patients and the presence of gas around the pancreas on imaging [89, 90]. Empirical AB may be initiated in these patients, with ABs that can penetrate the pancreas well (carbapenem alone; or quinolone, ceftazidime, or cefepime combined with an anaerobic agent such as metronidazole)being recommended [27, 47, 48]. Fine needle aspiration (FNA) or sampling is not recommended in such patients. Necrosectomy may be scheduled for patients who show no improvement, but should be delayed as much as possible, since many patients respond well to AB therapy [48, 90–92]. Antibiotic therapy should have been completed 4 weeks prior to a decision of necrosectomy. For the necrestomy, endoscopic or invasive percutaneous procedures should be tried first, and if these fail, surgery should be scheduled [47, 48, 52, 91–93].
