The effect of maternal flora on Candida colonisation in the neonate

Colonisation may be the first step for the development of Candida infection. The source of neonatal colonisation is thought to be the hospital environment or the maternal vaginal tract. This study investigated to what extend Candida isolates in neonates are similar to isolates from their mother's vaginal tract. Vaginal samples were collected from 347 pregnant women within 48h before delivery. Samples from oral and rectal mucosa of their neonates were collected within 24-72h after delivery, were cultured and yeast species were identified. Antifungal susceptibility tests against six antifungal agents were performed. All paired isolates from mother and infant were genotyped by pulse field gel electrophoresis. A total of 82 mothers and of 16 infants were found colonised by Candida spp. C.albicans was the most common species in pregnant women (n=68) followed by C.glabrata (n=11). Only C.albicans was isolated from infants, mainly (14/16) from rectal site. All colonised neonates were born to mothers colonised by C.albicans. Candida genotyping revealed identical strains in all investigated neonate-mother pairs. All isolates were susceptible to amphotericin B. Our findings strongly suggest that vertical transmission has the principal role in the neonatal colonisation by C.albicans in the very first days of life.