Evaluation of the diversity and bacterial composition of healthy, full-term infant faecal samples as based on birth delivery mode. Panel a indicates the box and whisker plot of the infant alpha-diversity calculated through Observed OTU index based on birth delivery methods. The bottom and top of the box represent the first and third quartiles, and the band inside the box is the median. Moreover, the ends of the whiskers represent the minimum and maximum of all data of the sample. Panel b reports the principal coordinate analysis (PCoA) of the collected infant samples, respectively, subdivided by age and birth delivery mode. Panel c displays the bacteria belonging to core- and accessory-microbiota of each delivery mode groups. The genera belonging to the core are highlighted with a green outline. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)