Antivirulence drugs against Acinetobacter baumannii: where do they stand?

Acinetobacter baumannii is a nosocomial Gram-negative pathogen of multi- and extensive-drug resistance phenotypes. In certain regions, multi-drug resistance rates can soar as high as 80-90%. Accordingly, reports by the World Health Organization and the Centers for Disease Control and Prevention underscore the urgent need for developing new antibiotics against A. baumannii. With the scarcity of novel antibiotics against this pathogen in the development pipeline, its rapid ability to develop and acquire resistance, and its versatile virulence weaponry, antivirulence therapeutics that can attenuate its virulence without adversely affecting growth may represent a promising treatment option with less selective pressure for resistance development. This review summarizes different antivirulence strategies against A. baumannii, which have been preclinically tested in various in vivo models. We also review different challenges and opportunities related to the realization of A. baumannii antivirulence drugs for clinical use.