The Role of a Multi-strain Probiotic in Very Low Birth Weight Premature Infants

Prematurity leads to the birth of a neonate who is not developmentally ready to enter the outside world. The neonate’s immature organs still need to develop fully to survive outside the protective environment of the womb. Immaturity can increase the risk of short-term morbidity [e.g. hospital-acquired bloodstream infection (HA-BSI), necrotising enterocolitis (NEC), and failure to grow]. It can also increase the risk of long-term neurodevelopmental and/or metabolic disorders (as seen in metabolic syndrome) and mortality. This thesis focused on the role that a multi-strain probiotic can play in preventing common short-term morbidities in very and extremely low birth weight preterm neonates. In Chapter 1, a review of the literature provided a background of what is known with respect to the premature neonate’s immature gut, the development and function of the microbiome, factors affecting the microbiome, consequences of dysbiosis and the possible role probiotics can play in reducing short-term morbidities in the preterm neonate. Chapter 2 provided a brief overview of the study methodology. Chapter 3 explored preterm neonates’ vulnerability to dysbiosis, as peri-rectal swab colonisation with drug-resistant Gram-negative bacteria (DR-GNB) was already present shortly after birth. Encouragingly, we found that probiotics can effectively reduce the peri-rectal colonisation of pathogenic DR-GNB by day 7, with an even more pronounced effect by day 14. On the day of enrolment 15% of the neonates showed peri-rectal colonisation with DR-GNB, indicating probable maternal-to-neonate (vertical) bacterial transmission or environmental acquisition at time of delivery, with no difference between the probiotic and placebo groups. By day 7 (corresponding to early gut colonisation), neonates in the probiotic group were 57% less likely to have peri-rectal DR-GNB colonisation and by day 14 (corresponding to late gut colonisation), neonates in the probiotic group were 93% less likely to have peri-rectal DR-GNB colonisation. The protective ...