OBJECTIVETo investigate the spectrum of bacteria and fungi in different sites in severe acute pancreatitis (SAP).

METHODSThe prospective study was performed in 205 patients with SAP treated from January 2000 to December 2008. The Infection rate of bacteria and fungi was observed prospectively in pancreatic necrosis and(or) pus form abdomen, body fluids and deep vein catheter in SAP. Body fluids and pancreatic necrosis were cultured twice a week. Central venous catheter was cultured when it had been placed for two weeks. Blood was cultured for bacteria and fungi when body temperature was more than 39 degrees C. Constituent ratio of bacteria and fungi was observed in different sites and in all sites within 28 days after onset of SAP.

RESULTSThere were 937 pathogens, among which infection rates of gram-negative bacteria was higher than gram-positive bacteria and fungi (P < 0.05), the infection rates of gam-positive bacteria and fungi were similar. Infection rates of gram-negative bacteria in pancreatic necrosis (55.2%), bile (55.4%), blood (68.1%) and central venous catheter (44.4%) were increased significantly (P < 0.05) compared with gram-positive bacteria and (30.2%, 33.9%, 23.4%, 38.9%) and fungi (14.6%, 10.7%, 8.5%, 16.7%); however, infection rate of fungi (59.6%) was increased significantly (P < 0.05) compared with gram-negative bacteria (24.0%) and gram-positive bacteria (16.3%) in urine; infection rate of gram-negative bacteria (53.2%) was significantly higher (P < 0.05) than that of fungi (27.1%) and gram-positive bacteria (19.7%) in sputum. Infection rate of non-zymogenic bacteria (Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia) in gram-negative bacteria in pancreatic necrosis, bile, blood, central venous catheter and sputum was significantly higher than that of zymogenic bacteria (Klebsiella pneumoniae, Escherichia coli and Enterobacter cloacae) (P < 0.01); infection rate of zymogenic bacteria (Klebsiella pneumoniae, Escherichia coli) was higher significantly (P < 0.01) than that of non-zymogenic bacteria (Pseudomonas aeruginosa, Acinetobacter baumannii). Infection rate of staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus was significantly higher (P < 0.05) than that of Enterococcus faecalis and Enterococcus faecium in pancreatic necrosis and sputum;but infection rate of Enterococcus faecium in bile and urine was significantly higher than other gram-positive bacteria (P < 0.05). There was not difference among gram-positive bacteria;however, infection rate of Staphylococcus epidermidis in central venous catheter was increased significantly (P < 0.05). Infection rate of candida mycoderma in pancreatic necrosis, bile, urine and sputum was significantly higher than that of tricho bacteria (P < 0.05). The peak of infection rate of microbes in body fluid was within 2 to 3 weeks.

CONCLUSIONSConstituent ratio in gram-negative, gram-positive bacteria and fungi as well as their species in different sites is diverse. The peak of infection rate of microbes is 2 to 3 weeks after onset of the disease.