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

https://doi.org/10.1016/j.jpeds.2010.09.007Get rights and content

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.

Section snippets

Methods

In this prospective, monocenter study, we included infants born at GA ≤30 weeks who were admitted to the neonatal intensive care unit (NICU) before 48 hours of life and whose mother received antenatal steroids. Feeding started when the attending physician deemed it advisable, with 20 mL/kg/day of pasteurized human milk (HM). This was increased by 10 mL/kg/day until full enteral feeding (160 mL/kg/day) was reached. Pooled pasteurized HM was provided as long as infants weighed <1500 g. At that

Results

Of the 30 eligible consecutive infants included between Oct 1, 2006, and Mar 31, 2007, one was excluded from analyses because of early death from pericardial effusion on day 11. Characteristics of the study population are reported in Table I. Most infants were born before 28 weeks gestation (n = 16, 55.2%). One infant born after 27 weeks gestation had a NEC grade 2 on day 19. All the infants received pooled pasteurized HM for a median duration of 36 days (interquatile range [IQR], 25-38), with

Discussion

In this prospective study, the diversity of microflora changed progressively during the first 8 weeks of life, and most infants had staphylococci in their stools. Furthermore, we showed a positive relationship between the diversity of intestinal microflora, digestive tolerance, and weight gain. This longitudinal study included a large number of very preterm infants with fully documented clinical characteristics and microflora analysis on the basis of a recently validated molecular approach

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    The authors declare no conflicts of interest.

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