Figure 7.

Ethanol-stimulated virulence mutants of A. baumannii. Mutants were generated as described in Materials and Methods. (A) Six individual A. baumannii mutants were incubated on NGM (wells a–f) or NGM + 1% ethanol (wells g–j). A single L4 stage worm was inoculated onto lawns of each mutant and allowed to proliferate for 4 d. Avirulent bacterial mutants were recovered as those that allowed the worms to consume the bacterial lawns as fast or faster on NGM + 1% ethanol as on NGM alone; e.g., mutant b (b,h). (B) Six individual A. baumannii mutants were mixed with D. discoideum amoebae and incubated on SM/5 + 1% ethanol (wells a–f). These are not the same mutants as shown in A. Avirulent mutants were defined as those that allowed amoebae plaque formation; e.g., mutant d.