Table 1

Characteristics of wild-type and antibiotic-resistant S. typhimurium LT2

StrainPhenotype/selectionNo. of independent isolatesGenotype (mutation)Generation time, minMIC
JB270Wild-type * rpsL+ (AAA42)2622416
JB271Restrictive SmR * rpsL106 (ACA42)29>1,024
JB272Restrictive SmR * rpsL116 (AAC42)33>1,024
JB273Nonrestrictive SmR * rpsL105 (AGA42)27>1,024
JB274Mouse-selected fast-growing suppressor of JB271 1(AAA42)262
JB275Mouse-selected fast-growing suppressor of JB271 2(CGT93 → CAT93)25>1,024
JB276Mouse-selected fast-growing suppressor of JB271 7(AGA42)27>1,024
JB277 and JB290Mouse-selected fast-growing suppressor of JB27210(AGA42)27>1,024
JB278LB-selected fast-growing suppressor of JB271 4(AGA42)26>1,024
JB279LB-selected fast-growing suppressor of JB272 1rpsE (GGT108 → AGT108)29>1,024
B221LB-selected fast-growing suppressor of JB272 1rpsD (AAG205 → AAC205)29>1,024
JB219LB-selected fast-growing suppressor of JB272 2Suppressor mutations extragenic to rpsD, rpsE, and rpsL29>1,024
JB280RifR * rpoB (†)44>256
JB281RifR * rpoB (†)58>256
JB282Mouse-selected fast-growing suppressor of JB280 2(†)2616
JB283Mouse-selected fast-growing suppressor of JB281 1(†)2716
JB284Mouse-selected fast-growing suppressor of JB281 1(†)32>256
JB285NalR * gyrA (†)25>256
JB286NalR * gyrA(†)31>256
JB288Mouse-selected suppressor of JB286 1(†)26>256
JB289Mouse-selected suppressor of JB286 1(†)278
  • The suppressor mutants were isolated as described in the text. The generation times are averages of at least three measurements in rich medium (Luria–Bertani broth) cultures at 37°C. The variance was approximately ±1 min of the average values. Antibiotic minimal inhibitory concentrations (MIC, μg/ml) were determined using E-tests (Materials and Methods). 

  • *Not applicable. 

  • Not determined.