Prevalence of RND efflux pump regulator variants associated with tigecycline resistance in carbapenem-resistant Acinetobacter baumannii from a worldwide survey.

The most prevalent tigecycline resistance mechanisms were caused by alterations in the regulators of RND-type efflux pumps. These data provide the basis for further characterization of regulator alterations and their contribution to increased efflux and tigecycline resistance, and also should be taken into account in drug discovery programmes to overcome the contribution of efflux pumps.