Identification of a streptogramin A acetyltransferase gene in the chromosome of Yersinia enterocolitica

Streptogramins are polypeptide antibiotics inhibiting protein synthesis by the prokaryotic ribosome. Grampositive organisms are susceptible to strepto gramins, while most gram-negative bacteria are intrinsically resistant. We have found a genomic fragment from a Yersinia enterocolitica isolate with a n open reading frame coding for a polypeptide similar to the virginiamycin acetyltransferases found in various plasmids from gram-positive bacteria. T he susceptible Escherichia coli strain DB10 was transformed to resistance t o the type A streptogramins and to mixed (A + B) streptogramins upon introd uction of a plasmid containing that gene. In addition, we showed streptogra min acetylating activity in vitro dependent on the presence of the Y. enter ocolitica sat gene. Southern blot hybridization experiments showed that the sat gene was present in all the Y. enterocolitica isolates examined. These data together show that the gene in the Y. enterocolitica chromosome encod ed an active streptogramin acetyltransferase. The deduced sequence of the Y . enterocolitica Sat protein was close to those of sat gene products found in gram-positive bacteria and cyanobacteria, suggesting a common evolutiona ry origin.