Decreased gut microbiota diversity, delayed Bacteroidetes colonisation and reduced Th1 responses in infants delivered by caesarean section.
OBJECTIVE
The early intestinal microbiota exerts important stimuli for immune development, and a reduced microbial exposure as well as caesarean section (CS) has been associated with the development of allergic disease. Here we address how microbiota development in infants is affected by mode of delivery, and relate differences in colonisation patterns to the maturation of a balanced Th1/Th2 immune response.


METHODS
The postnatal intestinal colonisation pattern was investigated in 24 infants, born vaginally (15) or by CS (nine). The intestinal microbiota were characterised using pyrosequencing of 16S rRNA genes at 1 week and 1, 3, 6, 12 and 24 months after birth. Venous blood levels of Th1- and Th2-associated chemokines were measured at 6, 12 and 24 months.


RESULTS
Infants born through CS had lower total microbiota diversity during the first 2 years of life. CS delivered infants also had a lower abundance and diversity of the Bacteroidetes phylum and were less often colonised with the Bacteroidetes phylum. Infants born through CS had significantly lower levels of the Th1-associated chemokines CXCL10 and CXCL11 in blood.


CONCLUSIONS
CS was associated with a lower total microbial diversity, delayed colonisation of the Bacteroidetes phylum and reduced Th1 responses during the first 2 years of life.
Department of Preparedness, Swedish Institute for Communicable Disease Control, , Solna, Sweden.
Hedvig E
HE
Jakobsson
Thomas R
TR
Abrahamsson
Maria C
MC
Jenmalm
Keith
K
Harris
Christopher
C
Quince
Cecilia
C
Jernberg
Bengt
B
Björkstén
Lars
L
Engstrand
Anders F
AF
Andersson
D000367:Age Factors; D041963:Bacteroidetes / Q000235:genetics / Q000502:physiology*; D002585:Cesarean Section / Q000009:adverse effects*; D054357:Chemokine CXCL10 / Q000097:blood* / Q000502:physiology; D054371:Chemokine CXCL11 / Q000097:blood* / Q000502:physiology; D004269:DNA, Bacterial / Q000235:genetics; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular / Q000502:physiology; D007223:Infant; D007231:Infant, Newborn; D007422:Intestines / Q000382:microbiology*; D008297:Male; D064307:Microbiota / Q000235:genetics / Q000502:physiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D018417:Th1 Cells / Q000502:physiology*
D054357:Chemokine CXCL10; D054371:Chemokine CXCL11; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
Chemokines; Infant Gut; Intestinal Bacteria; Intestinal Microbiology; Molecular Biology