Subinhibitory concentrations of imipenem induce increased resistance to methicillin and imipenem in vitro in methicillin-resistant Staphylococcus aureus.
Methicillin-resistant (MR) Staphylococcus aureus that was susceptible to less than 0.75 micrograms of imipenem per ml demonstrated inducible resistance. MR S. aureus preincubated with 0.05 microgram of imipenem per ml grew in medium with an imipenem concentration of 32 micrograms/ml, and methicillin MICs increased 20-fold. Non-MR S. aureus exhibited no induction. Preincubation with methicillin produced no effect. Induction appeared to be a unique interaction of imipenem with MR S. aureus.
D004790:Enzyme Induction / Q000187:drug effects; D015378:Imipenem; D008712:Methicillin / Q000494:pharmacology*; D010403:Penicillin Resistance; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000254:growth & development; D013845:Thienamycins / Q000494:pharmacology*; D001618:beta-Lactamases / Q000378:metabolism
D013845:Thienamycins; D015378:Imipenem; D001618:beta-Lactamases; D008712:Methicillin