Table 3.

Binding affinities of PBP 1 for mezlocillin and penicillin G in the Amoxs and Amoxrstrainsa

AbxPhenotypeControl abs.1× MIC10× MIC100× MIC
Abs.% DecreasebAbs.% DecreaseAbs.% Decrease
MezlS2.45 ± 0.032.04 ± 0.39170.39 ± 0.19840.07 ± 0.0197
MezlR2.51 ± 0.142.39 ± 0.17ND1.37 ± 0.38450.04 ± 0.0198
Pen GS2.87 ± 0.022.89 ± 0.05ND2.41 ± 0.14160.59 ± 0.2379
Pen GR2.57 ± 0.042.68 ± 0.12ND2.57 ± 0.11ND0.48 ± 0.1781
  • a H. pylori membrane fractions were preincubated with either mezlocillin or penicillin G at 1, 10, or 100 times the MIC prior to labeling with 4 μg of bio-Amox per ml, separated by SDS-PAGE, and visualized on Western blots. These blots were then quantitatively examined by laser densitometry. Control values represent bio-Amox labeling without preincubation with a competing antibiotic. Abx, antibiotic treatment; Abs., absorbance; Mezl, mezlocillin; Pen G, penicillin G; S, Amoxs H. pylori; R, Amoxr H. pylori; ND, decrease of ≤5%. Data represent the means ± standard errors of the means determined from three separate experiments.

  • b % Decrease, percent decrease in absorbance compared to control.