The Safety of Probiotic Prophylaxis in Preterm Infants for the Prevention of Necrotising Enterocolitis

Abstract

Background: Necrotising enterocolitis (NEC) is a common and potentially devastating disease in very preterm infants. The use of probiotics halves the incidence of NEC, and they are routinely used in preterm infants in Australasia. However, there remain concerns about their safety, including the reliability of the contents of probiotic products, the risk of the probiotic organisms infecting the preterm infant, and the potential for the probiotic organisms to colonise the neonatal unit. Aims: To determine: Aim 1) the concentration of probiotic organisms present in a probiotic product commonly used in preterm babies and if there was any contamination over a decade of surveillance; Aim 2) the incidence of probiotic bacteraemia in very preterm or very low birth weight infants, who received prophylactic probiotics. And Aim 3) if the neonatal unit environment is contaminated with organisms from the prophylactic probiotic routinely administered to very low birth weight infants for prevention of necrotising enterocolitis. Methods: Aim 1) Reviewed a decade of surveillance on the concentration of probiotic organisms and presence of contamination in probiotic products commonly used in preterm infants in Australasia. Aim 2) A retrospective observational cohort study of the incidence of bacteraemia with probiotic organisms in preterm infants eligible for probiotic prophylaxis for seven years before and after the introduction of routine probiotic use. Aim 3) A multi-centre study testing multiple surfaces in the neonatal unit for the presence of the probiotic organisms. Results: Probiotic samples did not consistently match label claims, with the concentration of organisms reducing over time. Routine probiotic use was associated with probiotic bacteraemia, incidence 0.2%, all cases had a full recovery. The study investigating the third aim was paused due to COVID-19 related restrictions, the protocol is presented in this thesis. Conclusion: In this thesis we have shown that the contents of probiotic products do not consistently correlate with label claims and that the use of prophylactic probiotics in this vulnerable population is associated with a rare risk of probiotic bacteraemia. These are both concerning and warrant further consideration. However, they do not outweigh the significant benefits of probiotic use in this population.