Activation of the cryptic aac(6')-Iy aminoglycoside resistance gene of Salmonella by a chromosomal deletion generating a transcriptional fusion.

ABSTRACT: Salmonella enterica subsp. enterica serotype Enteritidis BM4361 and BM4362 were isolated from the same patient. BM4361 was susceptible to aminoglycosides, whereas BM4362 was resistant to tobramycin owing to synthesis of a 6'-N-acetyltransferase type I [AAC(6')-I]. Comparative analysis of nucleotide sequences, pulsed-field gel electrophoresis patterns, and Southern hybridizations indicated that the chromosomal aac(6')-Iy genes for the enzyme in both strains were identical and that BM4362 derived from BM4361 following a ca. 60-kb deletion that occurred 1.5 kb upstream from the resistance gene. Northern hybridizations showed that aac(6')-Iy was silent in BM4361 and highly expressed in BM4362 due to a transcriptional fusion. Primer extension mapping identified the transcriptional start site fo

SUBMITTER: Magnet S 

PROVIDER: S-EPMC94128 | biostudies-literature | 1999 Nov

REPOSITORIES: biostudies-literature