BPEI potentiates
β-lactam activity against MRSA 700787, but
not MSSA 25923 or E. coli 11775. Checkerboard assays
show that BPEI potentiates oxacillin (A), amoxicillin (B), and ampicillin
(C) activity against MRSA 700787. BPEI does not potentiate vancomycin
(D) activity. No synergy is seen between β-lactams and BPEI
against MSSA 25923 (E) or E. coli 11775 (F). Each
assay was performed as three separate trials, and the presented data
is shown as the average change in OD600. The structure
of BPEI (G) is shown (n = 1, MW = 600 Da; n = 2, MW = 1200 Da; n = 3, MW = 1800 Da).