Measurement of Neutrophil Membrane CD64 as an Early Indication of Neonatal Infection and Necrotising Enterocolitis (NEC).

New born infants (neonates) and particularly premature infants are more at risk of developing bacterial infections due to a number of different factors including immature immune systems, and because they are more likely to need invasive procedures such as chest drains that increase the potential for infection.

The signs of infection in babies can be non-specific and difficult to diagnose. Undetected infections which are not treated can quickly lead to sepsis, which is an over-exaggerated response by the immune system which can spread throughout the whole body and attack 'self' tissue leading to organ failure and death. It is therefore vital that infection in neonates can be diagnosed quickly in order to administer the best treatment.

The current 'gold standard' laboratory test for detecting infection is to culture samples of blood, urine or spinal fluid, which allows any bacteria present to be grown in the lab and identified. However this test can take 24-48 hours to give results, and due to the devastating consequences of not treating an infection in neonates it is now common practice to prescribe broad spectrum antibiotics to any neonate who presents with signs of infection and await test results.

This study will look at what happens to the white blood cells that make up part of the immune defence against infection when they encounter an infection. One type of white blood cell that is particularly important in fighting bacterial infections is called the neutrophil, and when it detects an infection, it becomes activated in order to fight it; during this activation process it expresses a protein marker called CD64 on its surface. The CD64 protein is expressed within hours of the onset of bacterial infections, so measuring the CD64 marker could provide much faster results than laboratory tests that are currently available.

If we could detect infections in neonates more rapidly then non-infected neonates (with negative CD64 result) could have antibiotic treatment stopped. This is beneficial as it reduces unnecessary treatment therefore reducing hospital stays and cost. It also reduces the use of antibiotics, the overuse of which can promote the development of antibiotic resistant strains of bacteria, which can colonize entire wards. It would also mean that infected neonates could receive more appropriate care, for example more specific antibiotics.