A single genotype of Acinetobacter baumannii expresses multiple antibiotic susceptibility phenotypes

It is common practice to define a bacterium with unequal antibiotic susceptibility phenotypes as a different genotype. Here, we describe the utility of this practice for Acinetobacter baumannii. We determined antibiotic susceptibility for 19 clinical isolates of A baumannii. Repetitive sequence polymerase chain reaction method was used to determine genotypes. Although all isolates were of the same genotype, 79% were predicted to be different based on susceptibility patterns. The antibiotic susceptibility phenotype does not accurately predict the genotype of A baumannii.