Table 2.

Hydrolysis ratios and equilibrium penicillin concentrations in the periplasm achieved at an extracellular penicillin concentration of 250 μM in isogenic strains ofN. gonorrhoeaea

StrainGenotypeMean ± SD hydrolysis ratiob (nc)Mean ± SD equilibrium penicillin concn (μM) in periplasmd (n)
FA19Wild type0.669 ± 0.033 (9)72 ± 2 (9)*
FA102 penA 0.643 ± 0.051 (6)67 ± 3 (6)* , **
FA136 penA mtr 0.516 ± 0.047 (7)44 ± 3 (7)** , ***
FA140 penA mtr penB 0.231 ± 0.058 (6)14 ± 3 (6)***
H1Wild type0.718 ± 0.050 (8)85 ± 3 (8)
H1-1 penA 0.747 ± 0.034 (4)90 ± 2 (4),
H1-2 penA mtr 0.635 ± 0.059 (4)65 ± 3 (4),††
H1-3 penA mtr penB 0.420 ± 0.048 (4)31 ± 3 (4)††
  • a Hydrolysis ratios and penicillin concentrations were determined by the method of Zimmermann and Rosselet (32). The strains were β-lactamase-producing, spontaneous rifampin-resistant mutants.

  • b Rate of hydrolysis of penicillin by intact cells: rate of hydrolysis by disrupted cells.

  • c n, number of determinations.

  • d P values from unpaired Student’st test between equilibrium periplasmic penicillin concentrations for the indicated pairs of strains: *, P= 0.1; **, P = 0.002; ***, P < 0.0001; †, P = 0.37; ‡, P = 0.013; ††,P = 0.002.