Defining the Intestinal Microbiota in Premature Neonates

Highly premature infants are susceptible to serious infections such as necrotizing enterocolitis (NEC) and late-onset blood stream infections (BSIs).

NEC is a poorly understood, potentially life-threatening bowel disorder. It is thought that bacteria proliferating abnormally in the bowel may play an important part in its cause, but no single pathogen has yet been identified.

BSIs are commonly caused by gut bacteria. As the highly premature gut is fragile and has increased permeability, poor motility and decreased immune defences, localised inflammation caused by abnormal bacterial growth may allow 'bystander' microbes to translocate through the gut into the blood stream leading to systemic infection.

The investigators will collect daily faecal samples from premature (<32 weeks) infants in the intensive care unit from the day of birth until they are discharged. By using newly developed molecular detection techniques the investigators aim to define more precisely than has ever previously been attempted, all the species of bacteria present in the faeces. This will enable comparison of the pre-morbid and post-morbid intestinal microbiota (all the bacteria in the gut) in premature neonates.

In a small proportion of infants who develop NEC, surgery will be required as part of treatment of the condition. In these infants the investigators will seek consent to collect a small part of the diseased bowel which has been removed. Similar analysis will be performed on these samples. The analysis of the tissue samples will give us an indication of how well the faeces act as a proxy for the intestinal microbiota.

In this ecological study of the evolution of the intestinal microbiota in preterm infants, by comparing samples from babies who develop NEC or late-onset BSI with those of well babies the investigators will be able to look for differences characteristic of the conditions. This information will help aid design of prevention or treatment strategies.