Dynamics and Clinical Evolution of Bacterial Gut Microflora in Extremely Premature Patients

Objective To determine baseline clinical characteristics that influence bacterial gut flora dynamics in very preterm infants and the relationship between gut flora dynamics and clinical evolution. Study design Prospective, monocentric study enrolling 29 consecutive very preterm infants. We collected data about growth, digestive tolerance, nutrition, and antibiotic use. Microflora in stool samples, collected between 3 and 56 days of life, was identified with direct molecular fingerprinting. Results Median (interquartile range) body weight and gestational age at birth were 950 g (760-1060 g) and 27 weeks (27-29 weeks), respectively. The diversity score (number of operational taxonomic units) increased 0.45 units/week (P < .0001), with staphylococci as the major group. Bifidobacterium was poorly represented. Gestational age (>= 28 weeks) and caesarean delivery independently correlated with better diversity scores during follow-up (P < .05). The 6-week diversity score inversely correlated with the duration of antibiotherapy (P = .0184) and parenteral feeding (P = .013). The microflora dynamics was associated with the digestive tolerance profile. Weight gain increased with increasing diversity score (P = .0428). Conclusion Microflora diversity settled progressively in very preterm infants. Staphylococci were the major group, and few infants were colonized with Bifidobacterium spp. Measures that may improve microflora could have beneficial effects on digestive tolerance and growth. (J Pediatr 2011;158:390-6).