Figure 1.
Gestational age and bacterial colonization of meconium.
(A) A larger percentage of meconium samples from infants <33 weeks gestational age tend to be colonized (74·3%; N = 35) compared to infants of >33 weeks gestational age (52·9%; N = 17). (B) The bacterial composition of meconium is dominated by few genera; on average the most abundant genera in any given sample comprised 57·3±22·5% of reads; <33 and >33 weeks is displayed by the black, dashed line. (C)Dominant genera contribute to low diversity, measured by Shannon index; this is indicative of a founding population. Furthermore, gestational age was not correlated with Shannon diversity index (Spearman: rho = 0·03, p = 0·85).
Table 1.
Phyla, family, and genera taxonomy significantly correlated with gestational age (*p<0·05, **p<0·001; Spearman correlation) are reported.
Figure 2.
Meconium microbiome is most suggestive of amniotic fluid origin.
(A) The average percent relative abundance in meconium samples of this study for genera reported in amniotic fluid, and the oral and vaginal cavities of pregnant women6,7,27 are displayed by the Venn diagram which distinguishes unique and shared maternal environments of genera. (B) The potential total mean contribution and standard deviation of any particular maternal locale (amniotic fluid5,6, oral21, or vaginal21), and the phyletic distribution of contributing genera is shown in the stacked bar plot. The color assignment is as follows: Actinobacteria = purple; Bacteroidetes = green; Firmicutes = blue; Fusobacteria = orange; Proteobacteria = red; Tenericutes = aquamarine.
Figure 3.
Inflammatory marker S100A12 was correlated with gestational age.
(A) Non-metric multidimensional scaling ordination plot depicting the relatedness of the bacterial communities from all meconium samples; communities from >33 week infants (blue) clustered more closely than those from <33 week infants (red). Analysis of similarity (ANOSIM) revealed that gestational age (<33 and >33 weeks) had the largest effect on meconium microbial structure (R = 0·16; p-value = 0·03). (B) Of the four predominant phyla, the relative abundance of Firmicutes and Actinobacteria was correlated with low gestational age (**p<0·01 & *p<0·05, respectively). (C) Genera negatively correlated with gestational age (**p<0·01) are presented. (D) Genera associated with mode of delivery (*p<0·05) were observed, though these differences are not as pronounced as the genera associated with gestational age.