TABLE 1.

Reversal of substitutions at amino acid positions in PBP 1A from isolate 3191 and the resulting effect of this mutagenesis on resistance levels in mutagenized R63191/2X/2B/1A strains compared to those for R63191/2X/2B/1A (penicillin MIC, 4 μg/ml; cefotaxime MIC, 2 μg/ml)

Mutagenic primerPosition of amino acids where reversal of substitutions occurredDrug MIC (μg/ml) for mutagenized R63191/2X/2B/1A
PenicillinCefotaxime
1316, 318, 32142
232642
333342
4351, 35842
5382, 38842
6393, 395, 39742
740542
841442
9443, 44742
10458, 45942
11473, 47542
1248542
13495, 49742
1450342
15517, 51842
1653342
175390.50.5
1854042
19546, 55042
20570, 57142
21574, 575, 576, 5770.250.25
2257942
23583, 58542
2460042
25606, 60942