TKT and escherichia coli infection: Unlike tktA or tktB, which are unequivocally present in both avian fecal E. coli and APEC, tkt1 was predominantly present among APEC (39.6%) but absent from most of the intestinal E. coli (6.25%) examined [27], suggesting that this gene may play a significant role in the pathogenesis of avian colibacillosis.