PPARA and escherichia coli infection: Further analysis using GSVA showed that PCD cluster A was enriched in certain pathways, such as pathogenic Escherichia coli infection, cell cycle, Vibrio cholerae infection and homologous recombination, whereas PCD cluster B was enriched in pathways related to glycine, serine, and threonine metabolism, fatty acid metabolism, histidine metabolism and PPAR signalling pathway (Figure 3C).