Antagonism between aminoglycosides and beta-lactams in a methicillin-resistant Staphylococcus aureus isolate involves induction of an aminoglycoside-modifying enzyme.

ABSTRACT: We encountered three clinical isolates of methicillin-resistant Staphylococcus aureus which were susceptible to netilmicin and arbekacin in the absence of beta-lactam antibiotics but which were resistant to them in the presence of beta-lactam antibiotics. One of these strains, KU5801, was used to further investigate the antagonism between aminoglycosides and beta-lactam antibiotics. beta-Lactam antibiotics induced bacterial synthesis of aminoglycoside-6'-N-acetyltransferase and 2"-O-phosphotransferase [AAC(6')-APH(2")] in association with decreased antimicrobial activities of aminoglycosides. A 14.4-kb EcoRI fragment that included the genes that control for beta-lactam-inducible aminoglycoside resistance was cloned from a 31-kb conjugative plasmid present in KU5801. Restriction fragment ma

SUBMITTER: Ida T 

PROVIDER: S-EPMC127169 | biostudies-literature | 2002 May

REPOSITORIES: biostudies-literature