Transmissible substrate-utilizing ability in enterobacteria

Three of 152 strains of Escherichia coli transmitted their ability to utilize sucrose (Sac+) to other strains by conjugation. The transfer factor of one of them and of a Sac+ Salmonella thompson strain was thermosensitive. The raffinose-utilizing ability of 27 of 163 E. coli strains was also transmissible. Transmissible raffinose-utilizing ability was a feature of porcine enterpathogenic strains possessing the K88 antigen. The determinants controlling raffinose utilization (Raf) and K88 antigen production were commonly transmitted together from these strains; so also was the determinant controlling enterotoxin production, but to a lesser extent. It was not possible to transfer lactose-utilizing ability from 320 strains of E. coli, salicin-utilizing ability from 12 strains of E. coli or dulcitol-utilizing ability from 99 strains of E. coli and 88 strains of salmonellae. Sucrose- and raffinose-utilizing ability were transmitted separately to several Salmonella sp., including Salm. typhi, to Shigella flexneri and Sh. sonnei and to a variety of strains of E. coli. A strain of Salm. typhimurium in which Sac had been established and a strain of E. coli in which Raf had been established survived less well in the alimentary tract of chickens than their Sac minus or Raf minus parent strains.