Figure 6. HAMLET and resistance development.

Methicillin adaptation of the MRSA strain NRS 384 after exposure to stepwise increasing concentrations of methicillin alone (1–512 µg/mL or 2.5–1,350 µM) or methicillin in combination with 100 µg/mL (6 µM) HAMLET. The filled blue circles show the methicillin MICs after each cycle when no HAMLET was used. The addition of 100 µg/mL of HAMLET reduced methicillin-induced resistance (blue unfilled circles). The unfilled green circle represents the MIC of methicillin of the bacteria grown in presence of HAMLET, when HAMLET was also present during the MIC assay to potentiate the effect of the antibiotic. Reintroduction of HAMLET to these isolates again returned the methicillin MIC back to the levels denoted by the green unfilled circle.