TABLE 3.

Comparison of antibiotic resistance profiles of vegetative cells of serovar Typhimurium 14028 prior to swarm-cell differentiation and following dedifferentiation from swarm cells that had been exposed to an antibiotic

AntibioticMIC (μg/ml)
Initial inoculumaSwarm front inoculumb
SolidSwimSolidSwim
Piperacillin1.51.51.51.5
Ceftazidime0.190.190.190.125
Polymyxin24242424
Kanamycin61266
Streptomycin812812
Ciprofloxacin0.0640.0640.0640.064
Rifampin4446
  • a Single colonies incubated overnight in NB (0.5% glucose) in the absence of antibiotics.

  • b Cells that were harvested from the swarm front that formed in the presence of an antibiotic and were than incubated overnight in NB (0.5% glucose).