The researchers studied the gut bacteria of newborn babies on their first and third day after birth. They collected stool samples from 50 babies and used a high-tech sequencing method to analyze the bacteria. They found that certain types of bacteria changed in abundance over time, with some increasing and others decreasing. The most common bacteria in both groups were Proteobacteria, Firmicutes, Bacteroidetes, and Actinobacteria. Some specific families and genera of bacteria also showed changes in abundance between the two days. Overall, the study provides insights into how the gut microbiota of newborns evolves in the first few days of life.