Effects of mode of delivery and necrotising enterocolitis on the intestinal microflora in preterm infants

Abstract

To investigate the effects of mode of delivery and of necrotising enterocolitis on the faecal microflora, 140 infants born before 33 weeks of gestation were followed up for symptoms of necrotising enterocolitis. Stool samples for gas-liquid chromatography and culture were collected twice weekly, and, when necrotising enterocolitis was suspected, for 2 months. For each infant with necrotising enterocolitis (n=21), two control infants matched for birth weight and gestational age were selected from the remaining study population. In gas-liquid chromatography analysis, the faecal bacterial microflora of infants born via caesarean section differed significantly from the gut microflora of those born via the vaginal route. The intestinal microflora showed a significant alteration in the necrotising enterocolitis group at time of diagnosis. At the onset of necrotising enterocolitis, faecal colonisation with Enterococcus species and Candida albicans was significantly more frequent in symptomatic infants than in controls. In infants with positive blood cultures and positive intestinal biopsy cultures, concomitant stool samples revealed the same microbial pathogens. In conclusion, the intestinal microbial colonisation in preterm infants born by caesarean section differs from that in preterm infants born via the vaginal route. A significant change in faecal microbial colonisation seems to occur at the onset of necrotising enterocolitis. Pathogens detected in the stools at that time might have a causative role in the development of the disease.

Elective cesarean delivery affects gut maturation and delays microbial colonization but does not increase necrotizing enterocolitis in preterm pigs

“…The above studies, in conjunction with other findings (18,28), suggest that caesarean delivery may be a risk factor of NEC. Yet, the lack of controlled studies has left this clinically important question unanswered.…”

“…The patterns of bacterial colonization are particularly important for preterm neonates because of their increased sensitivity to bacterial colonization (9,29), with aberrant bacterial growth causing severe gut dysfunction and disease (15,37). Delivery mode and diet are determinants of initial colonization and development of the bacterial assemblages in the infant gut (17,18). Exemplary of this are the different densities of bacterial colonization, stability, and diversity among CS and VD neonates (15,17,37,48).…”

“…The different assemblages of gut bacteria resulting from CS and VD (17) have been related to differences in intestinal functions and health (26) and incidence of NEC (18). However, the influence of birth mode on the mucosa-associated bacteria is not always evident, particularly when fecal samples are used as a surrogate for the entire gut microbiota (31).…”

Antenatal antibiotic exposure in preterm infants with necrotizing enterocolitis

“…15,17,32 A narrowing spectrum of microflora presages the development of NEC. 15 Wang et al 33 demonstrated that preterm infants with NEC had a predominance of proteobacteria in the stool, and suggested that limited bacterial diversity and pathogenic bacterial predominance may contribute to the susceptibiity of premature infants to NEC.…”

Investigation of the early intestinal microflora in premature infants with/without necrotizing enterocolitis using two different methods

“…Some studies have found an association between various bacterial species and NEC (15)(16)(17)(18)(19)(20), whereas others did not observe any association between NEC and any specific bacterial species (8,21).…”