Age-dependent susceptibility to intraabdominal abscess formation

Infection remains a major cause of morbidity and mortality in the surgical neonate, with the risk of developing infectious complications decreasing as age increases. Developmental changes in the immune system, as well as transplacentally acquired immunity, likely play a role in this differential risk. The purpose of this study was to determine whether there is an age-related susceptibility to intraabdominal abscess formation. The authors used a mouse model in which the combination of an aerobe, anaerobe, and adjuvant routinely forms abscesses. Litters of at least six C57 BL/6 mice were used. The mice received 10(7) of Enterococcus faecalis and 10(7) Bacteroides distasonis or 10(7) B distasonis alone. The mice were given 8 microL/g of 50% wheat bran (40 mg/mL) and 50% bacteria. There were at least four litters for each experiment. Intraabdominal abscesses were counted after 7 days. Ten-day-old mice had an incidence of intraabdominal abscesses that was similar to that of the adults (81% v 91%). There was a significant decrease in intraperitoneal infection after 10 days, until weaning (37% and 38%; P < .05). The authors conclude that there are significant developmental changes in susceptibility to intraabdominal abscess formation, which may reflect changes in peritoneal defense mechanisms.