NEONATAL SOCIETY ABSTRACTS
The culture-independent profiling of bacteria in preterm infants and correlation with bronchopulmonary dysplasia
Presented at the Neonatal Society 2009 Summer Meeting (programme).
Goss KCW4, Payne MS1, Connett GJ2, Kollamparambi T3, Legg JP2, Thwaites R4, Ashton M4, Puddy V3, Bruce KD1
1 School of Biomedical and Health Sciences, King’s College London,
2 Department of Paediatrics, Southampton General Hospital, Southampton University Hospitals NHS Trust, UK
3 Neonatal Intensive Care Unit, Princess Anne Hospital, Southampton University Hospitals NHS Trust, UK
4 Neonatal Intensive Care Unit, St Mary’s Hospital, Portsmouth Hospitals NHS Trust, UK
Background: The aetiology of bronchopulmonary dysplasia (BPD) is multifactorial and poorly understood with bacteria implicated in its development. Ureaplasma species have been associated previously (1) and a recent publication has related gastric fluid microbes and subsequent BPD (2).
Aims/Objectives: The aim of the study was to characterise the bacteria present in Nasogastric (NG) and Endotracheal (ET) aspirates from newborn preterm infants and relate these findings to clinical outcomes.
Design/Methods: Preterm infants <30 weeks gestation and <1250g born over a 12 month period in Southampton and Portsmouth’s neonatal intensive care units were eligible for inclusion. The study had site specific local ethical committee approval. The NG and ET aspirate samples were studied using both denaturing gradient gel electrophoresis (DGGE - a novel technique that profiles without prior culture the bacteria in a sample) and species-specific PCR to detect Ureaplasma parvum, Ureaplasma urealyticum and Mycoplasma hominis. Outcome measures were related to microbial findings.
Results: 55 infants were recruited and had samples processed. DGGE analyses identified bacterial species in 64% of NG and ET aspirates. 31 different organisms were identified including several implicated in the occurrence of preterm labour. Species specific PCR identified Mycoplasma spp. in 25% of NG and 11% of ET aspirates; a much higher incidence than previously published. Ureaplasma spp. were found in half of NG and ET samples.
Significant correlation existed between Ureaplasma spp. on ET aspirates and poor outcome for BPD (p = 0.012) and a significant inverse relationship with gestational age in weeks (p = 0.027). Mode of delivery had a significant effect on rate of detection of potentially pathogenic species in NG aspirates but did not influence outcome.
Conclusions: These results indicate the presence of a range of bacterial species in newborn preterm infants including those that have been causally related to preterm labour. Many are difficult to culture using standard techniques. The association between Ureaplasma spp. in ET aspirates and the subsequent development of BPD adds further support to the hypothesis that these organisms are causally related to lung injury in preterm neonates.
Acknowledgements: Laboratory work funded by The British Lung Foundation.
1. Cassell, G.H., et al., Association of Ureaplasma urealyticum infection of the lower respiratory tract with chronic lung disease and death in very-low-birth-weight infants. Lancet, 1988. 2(8605): p. 240-5.
2. Oue, S., et al., Association of gastric fluid microbes at birth with severe bronchopulmonary dysplasia. Arch Dis Child Fetal Neonatal Ed, 2009. 94(1): p. F17-22.