RESEARCH REPORTS P. Lif Holgerson*, L. Harnevik', O. Hernell2 A.C.R. Tanner Mode of Birth Delivery Affects and l. Johansson Oral microbiota in Infants University, 901 87 Umea, Sweden: Department of Clinical Sciences, Pediatrics Section, Umea University, Sweden; and Department of Molecular Genetics, The Forsyth Institut Cambridge, MA, and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Bosto MA, USA; *corresponding author, perillalif(@odont.um J Dent Res9o(10):11831188 ABSTRACT INTRODUCTION Establishment of the microbiota of the gut has been shown to differ between infants delivered by e first exposure to micro-organisms in vaginally delivered infants occurs Caesarian section(C-section) and those delivered during passage through the birth canal, whereas the first exposure to bacte vaginally. The aim of the present study was to ria in infants born by Caesarian section( C-section)is from the skin of parents and health providers, and medical equipment. Different modes of delivery compare the oral microbiota in infants delivered lead to differences in the intestinal microbiota in infants(Penders et al., 2006 by these different routes. The oral biofilm was Dominguez-Bello et al., 2010). Vaginally bom children have been reported to assayed by the Human Oral Microbe Identification have a more diverse gut microbiota, whereas children born by C-section had Microarray(HOMIM) in healthy three-month-old infants, 38 infants borm by C-section, and 25 nigher numbers of Clostridium difficile and delaved acquisition of bifidobac infants delivered vaginally. Among over 300 bac teria and Escherichia coli(ahrme et al, 2005; Penders et al., 2006). In the oral cavity, mutans streptococci were detected more frequently and at a younger terial taxa targeted by the HOMIM microarray, age in children delivered by c-section than in those delivered vaginally ( Slackia exigua was detected only in infants deliv- et al, 2005). These authors hypothesized that C-section, compared with vaginal ered by C-section. Further, significantly more bac- birth, lowered the exposure to commensal, protective bacteria from the mother terial taxa were detected in the infants delivered vaginally(79 specieslspecies clusters)compared during birth, reducing the natural barrier to colonization by oral pathogens Acquisition of oral bacteria in early childhood results mainly from transmis with infants delivered by C-section(54 species/ sion from the mother (Kononen, 2000; Tanner et al., 2002), but there is less species clusters). Multivariate modeling revealed a strong model that separated the microbiota of information about other factors influencing establishment of the microbiota in he oral cavity than reported for the gut. Establishment of the gut microbiota C-section and vaginally delivered infants into two was found not to be a predetermined species-by-species succession, but rather tudy indicated differences in the oral microbiota a coordinated interplay between extemal and intemal factors(Fanaro et al in infants due to mode of delivery, with vaginally environment during birth, the mother's microbiota, and infant feeding method delivered infants having a higher number of taxa (Fallani et al, 2010). Internal factors included the developmental stage of the detected by the HOMIM microarray gastrointestinal tract and host factors(Benson et al., 2010) The aim of the present study was to compare oral microbiota, seeking dif- KEY WORDS: newborn, Caesarian section, vag- ferences in colonization patterns in infants delivered vaginally or by C-section. inal delivery, bacterial taxa, HOMIM, Slackia The human Oral Microbe Identification Microarray was used to detect bacte rial taxa STUDY POPULATION METHODS DOI:10.11770022034511418973 Received February 16, 2011; Last revision July 6, 2011 All mothers living in a small inland town and a coastal university city in Northem Sweden who had delivered a healthy baby in the previous 3 mos were invited to consent for their infant to participate in the study. From 300 invited women, A supplemental appendix to this article is published elec- 207 accepted (69%), and all infants delivered by C-section(n=41)and 26 tronicallyonlyathttp://jdr.sagepub.com/supplemental. andomly selected vaginally delivered infants were selected for microbia O Intemational American Associations for Dental Research analyses. Phone interviews were conducted with the non-participants, and the1183 RESEARCH REPORTS Clinical DOI: 10.1177/0022034511418973 Received February 16, 2011; Last revision July 6, 2011; Accepted July 9, 2011 A supplemental appendix to this article is published elec￾tronically only at http://jdr.sagepub.com/supplemental. © International & American Associations for Dental Research P. Lif Holgerson1 *, L. Harnevik1 , O. Hernell2 , A.C.R. Tanner3 , and I. Johansson1 1 Department of Odontology, Cariology Section, Umeå University, 901 87 Umeå, Sweden; 2 Department of Clinical Sciences, Pediatrics Section, Umeå University, Sweden; and 3 Department of Molecular Genetics, The Forsyth Institute, Cambridge, MA, and Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA, USA; *corresponding author, pernilla.lif@odont.umu.se J Dent Res 90(10):1183-1188, 2011 Abstract Establishment of the microbiota of the gut has been shown to differ between infants delivered by Caesarian section (C-section) and those delivered vaginally. The aim of the present study was to compare the oral microbiota in infants delivered by these different routes. The oral biofilm was assayed by the Human Oral Microbe Identification Microarray (HOMIM) in healthy three-month-old infants, 38 infants born by C-section, and 25 infants delivered vaginally. Among over 300 bac￾terial taxa targeted by the HOMIM microarray, Slackia exigua was detected only in infants deliv￾ered by C-section. Further, significantly more bac￾terial taxa were detected in the infants delivered vaginally (79 species/species clusters) compared with infants delivered by C-section (54 species/ species clusters). Multivariate modeling revealed a strong model that separated the microbiota of C-section and vaginally delivered infants into two distinct colonization patterns. In conclusion, our study indicated differences in the oral microbiota in infants due to mode of delivery, with vaginally delivered infants having a higher number of taxa detected by the HOMIM microarray. KEY WORDS: newborn, Caesarian section, vag￾inal delivery, bacterial taxa, HOMIM, Slackia exigua. Introduction T he first exposure to micro-organisms in vaginally delivered infants occurs during passage through the birth canal, whereas the first exposure to bacte￾ria in infants born by Caesarian section (C-section) is from the skin of parents and health providers, and medical equipment. Different modes of delivery lead to differences in the intestinal microbiota in infants (Penders et al., 2006; Dominguez-Bello et al., 2010). Vaginally born children have been reported to have a more diverse gut microbiota, whereas children born by C-section had higher numbers of Clostridium difficile and delayed acquisition of bifidobac￾teria and Escherichia coli (Ahrné et al., 2005; Penders et al., 2006). In the oral cavity, mutans streptococci were detected more frequently and at a younger age in children delivered by C-section than in those delivered vaginally (Li et al., 2005). These authors hypothesized that C-section, compared with vaginal birth, lowered the exposure to commensal, protective bacteria from the mother during birth, reducing the natural barrier to colonization by oral pathogens. Acquisition of oral bacteria in early childhood results mainly from transmis￾sion from the mother (Könönen, 2000; Tanner et al., 2002), but there is less information about other factors influencing establishment of the microbiota in the oral cavity than reported for the gut. Establishment of the gut microbiota was found not to be a predetermined species-by-species succession, but rather a coordinated interplay between external and internal factors (Fanaro et al., 2003; Penders et al., 2006). External factors for the gut microbiota included the environment during birth, the mother’s microbiota, and infant feeding method (Fallani et al., 2010). Internal factors included the developmental stage of the gastrointestinal tract and host factors (Benson et al., 2010). The aim of the present study was to compare oral microbiota, seeking dif￾ferences in colonization patterns in infants delivered vaginally or by C-section. The human Oral Microbe Identification Microarray was used to detect bacte￾rial taxa. Study Population & Methods Study Population All mothers living in a small inland town and a coastal university city in Northern Sweden who had delivered a healthy baby in the previous 3 mos were invited to consent for their infant to participate in the study. From 300 invited women, 207 accepted (69%), and all infants delivered by C-section (n = 41) and 26 randomly selected vaginally delivered infants were selected for microbial analyses. Phone interviews were conducted with the non-participants, and the Mode of Birth Delivery Affects Oral Microbiota in Infants