Infection and acute pancreatitis
Infectious complications are a common diagnostic and therapeutic problem in severe acute pancreatitis. Secondary infection in mild oedematous pancreatitis is rare, occurring in less than 1 per cent of patients but it remains the single most common cause of death in necrotizing pan~reatitisl-~. In the past few years the authors, among others, have performed a careful investigation of the role of infection in this disease.
Septic complications are most frequent in patients who have infected pancreatic necrosis. A number of investigators have examined the spectrum of bacteria found in this condition, by microbiological examination of intraoperative smears or of samples obtained by computed tomography (CT )-guided fine-needle aspiration.
Bacteria are found in 40-70 per cent of all patients suffering from necrotizing pancreatiti~~?~?~. The frequency of positive cultures correlates with the duration of disease and the extent of necrosis. Of patients with necrotizing pancreatitis operated on during the first week after hospital admission, 24 per cent have bacterial contamination of the necrotic areas. This increases to 36 and 72 per cent in the second and third weeks respectively*. The bacterial spectrum resembles that of the intestinal flora but also includes Gram-positive bacteria, anaerobes and, in some cases, fungi ( Table I), suggesting an enteric origin. However, the exact source of the bacteria and their route into the pancreatic region remain uncertain'.