Reduced enterobacterial and increased staphylococcal colonization of the infantile bowel: an effect of hygienic lifestyle?

• The modern Western lifestyle may have altered the composition of the commensal microflora. Here, we investigated the first year's intestinal colonization pattern in 99 vaginally delivered Swedish infants and 17 delivered by cesarean section. Rectal swabs obtained at 3 d of age were cultured for aerobic bacteria and fecal samples obtained at 1, 2, 4, and 8 wk and at 6 and 12 mo of age were cultivated quantitatively for aerobic and anaerobic bacteria. Vaginally delivered infants more often had Escherichia coli compared with cesarean section-delivered infants, whereas the latter more frequently carried other enterobacteria, such as Klebsiella and Enterobacter. Independent of delivery mode, it took 2 mo until most infants were colonized by enterobacteria, traditionally the first colonizers. In contrast, coagulase-negative staphylococci colonized 99% of the infants from d 3 onwards. The poor adaptation of staphylococci to the gut was shown by declining population sizes after some weeks. Dominating anaerobes were initially bifidobacteria and clostridia, whereas Bacteroides initially colonized only 30% of vaginally delivered infants and increased very slowly in prevalence. Bacteroides colonization was delayed up to 1 y in cesarean section-delivered compared with vaginally delivered infants. Our results show that some "traditional" fecal bacteria are acquired late today especially in cesarean section-delivered infants, probably due to limited environmental circulation. In their absence, skin bacteria like staphylococci have become the first gut colonizers.

Nyckelord

Anti-Bacterial Agents

pharmacology

Bacteria

Anaerobic

isolation & purification

Cesarean Section

Enterobacteriaceae

drug effects

isolation & purification

Female

Humans

Hygiene

Hypersensitivity

microbiology

Infant

Newborn

Intestines

microbiology

Life Style

Male

Natural Childbirth

Pregnancy

Staphylococcus

drug effects

isolation & purification

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)