LAUSR

It has been postulated that changes in prevalence of E. coli isolates with particular virulence genes in animals may be affected by many factors including age, feed, geographical location and stress. The weaning period represents stressful stage during the growth of farm animals. To evaluate if weaning stress affects the prevalence of E. coli possessing virulence genes; shiga toxin (Stx), hemolysin (hly) and intimin (eae) in young meat goats, fecal samples were collected during pre-weaning period, day of weaning (0DPW), one day after weaning (1DPW), two days after weaning (2DPW) and 7 days after weaning (7DPW). Two hundred forty seven two E. coli isolates were screened for the virulence genes. All four virulence genes (Stx1, Stx2, Hly, and eae) evaluated were detected in E. coli during the peri-weaning period while only stx1, eae and hly were detected during the pre-weaning period. No Stx2 had been detected during the pre-weaning period. Both Stx1 and Hly frequency of detection increased significantly from 0DPW to 2DPW and then decreased on 7DPW. The Stx2 gene remained relatively the same between 0DPW and 7DPW. The frequency of eae detection was highest during the pre-weaning period but also increased significantly from 0DPW to 7DPW. Further characterization of peri-weaning isolates possessing either Stx2 or eae revealed that some belonged to serotypes important to animal and public health including O26, O103 and O146. We highlight a previously unreported finding on pattern of colonization by E. coli in young meat goats before and during peri-weaning period. This trend may be suggestive that strains of E. coli harboring specific virulence genes proliferate during times of stress such as weaning in young meat goats while others predominantly colonize very young animals. The significance of E. coli isolates possessing the various virulence genes in relation to animal health need further evaluation.