Maternal separation disrupts the integrity of the intestinal microflora ininfant rhesus monkeys

The integrity of the indigenous microflora of the intestines after maternal separation was investigated in infant rhesus monkeys to determine whether psychological stress may lead to an internal environment conductive to path ogen infection. Thew stability of the indigenous microflora were estimated by enumeration of total and gram-negative aerobic and facultatively anaerob ic bacterial species, specifically Lactobacilli, from coprocultures taken b efore and after material separation. In addition, behavioral and cortisol r esponses to separation were correlated to the microflora. A significant dec rease in fecal bacteria, especially Lactobacilli, was evident on day 3 post separation, with? a return to baseline by the end of the,I cck. The drop in the microflora uas correlated with the display of stress-indicative behavi ors, but not with cortisol secretion. In addition, infants who displayed nu merous stress-indicative behaviors were more susceptible to opportunistic b acterial infection. These results suggest that strong Emotional reactions t o disruption of the mother-infant bond may increase vulnerability to diseas e. (C) 1999 John Wiley & Sons, Inc.