Fig. 2. E-test strip comparison of polymyxin and kanamycin resistance of strain 14028 in vegetative and swarm states.

Resistance to polymyxin (PO) is shown in the upper level and kanamycin (KM) is shown below. Initial inoculum: cells were grown overnight in NBG then spread-plated on NBG containing 1.5% agar (solid) or spot-plated on 0.25% (swim), or 0.5% (swarm) agar. Swarm front inoculum: cells were harvested from the swarm front at the highest concentration of the antibiotic from the initial inoculum (i.e. middle images) and grown overnight in NBG, then inoculated on either solid or swim plates as done initially.