The use of molecular techniques for bacterial detection in the analysis of gastric aspirates collected from infants on the first day of life

NMUH Staff Publications

86

<p class="MsoNoSpacing"><span lang="EN-US">Prospective service evaluation of the utility of molecularmethods to analyse neonatal gastric aspirate specimens in a single neonatalunit and associated maternity unit. 43 newborn infants investigated for sepsiswith median gestational age of 39 weeks (range 31-41 weeks) and median birthweight 3050 grams (range 1250-4220 g). Gastric aspirates routinely collectedwithin 12h of birth were analysed using conventional and molecular methods for bacterialdetection, bacterial DNA load and sequencing to identified bacterial species.</span></p><p class="MsoNoSpacing"><span lang="EN-US">RESULTS: Bacterial DNA loads varied from 0.03 to 1736pg/microl of DNA extract (1 microl of DNA extract equivalent to 4 microl gastricaspirate). Bacteria were identified in 30/43 (70%) of samples by molecularmethods and 10/43 (23.3%) of samples by culture. Cultures were only positivewhen the bacterial DNA exceeded 4.5 pg/microl of extract. Infants withprolonged rupture of membranes (>24h prior to delivery) had a DNA load onaverage 23 times higher than those without (95%CI 3.7 to 141; p=0.001).Additional bacteria detected by molecular methods included many species thatare fastidious and potentially pathogenic including Leptotrichia spp., Serratiaspp., Ureaplasma spp., Veillonella spp., Haemophilus influenzae and Group BStreptococcus. Due to a low rate of adverse outcomes it was not possible tocorrelate bacterial identifications or DNA load with infant outcome.</span></p><p></p><p class="MsoNoSpacing"><span lang="EN-US">CONCLUSIONS: Molecular methods can identify bacteriafrom a greater proportion of gastric aspirate specimens that conventionalculture. Further work is required to establish whether this information can beused to improve infant outcomes.</span></p>