Dual Role of in Antibiotic Resistance and Virulence in Acinetobacter baumannii.

is an important Gram-negative pathogen in hospital-related infections. However, treatment options for infections have become limited due to multidrug resistance. Bacterial virulence is often associated with capsule genes found in the K locus, many of which are essential for biosynthesis of the bacterial envelope. However, the roles of other genes in the K locus remain largely unknown. From an evolution experiment, we obtained an isolate of the virulent and multidrug-resistant strain MDR-ZJ06, called MDR-ZJ06, which has an insertion by the IS transposon in (encoding UDP--acetylglucosamine C-6 dehydrogenase), a gene found in the K locus. The isolate showed an increased resistance toward tigecycline, whereas the MIC decreased in the case of carbapenems, cephalosporins, colistin, and minocycline. By using knockout and complementation experiments, we demonstrated that is important for the synthesis of lipooligosaccharide and capsular polysaccharide and that disruption of the gene affects the morphology, drug susceptibility, and virulence of the pathogen.