E coli is the most common aerobic bacteria involved in the pathogenesis of acute suppurative bacterial peritonitis, whereas the most common anaerobic bacteria involved is Bacteroides. Acute suppurative bacterial peritonitis (secondary bacterial peritonitis) usually occur as a result of acute infection of peritoneum resulting from perforation following appendicitis or diveiculitis. Ref: Principles of Surgical Patient Care By C. J. Mieny, 2nd Edition, Pages 825-8.