Intra-abdominal infections (IAI) occur due to disruption of the normal anatomic barrier.
Hollow viscera is where common disruptions occur, which allows intraluminal bacteria to invade and proliferate in the usually sterile area (ie peritoneal cavity or retroperitoneum).
Community-acquired IAI is usually secondary to gastroduodenal perforation, ascending cholangitis, cholecystitis, appendicitis, colon diverticulitis with or without perforation, or pancreatitis.
Healthcare-associated IAI is usually secondary to leak or perforations from anastomosis or abscess from surgical site and/or wound infections.