AadT, a new weapon inAcinetobacter’sfight against antibiotics

A novel multidrug efflux pump, AadT from the Drug:H + antiporter 2 family, was discovered in Acinetobacter multidrug resistance plasmids. Here, we profiled the antimicrobial resistance potential and examined the distribution of this gene. Putative homologs of this efflux pump were encoded in many Acinetobacter species and other Gram-negative species, and were genetically associated with novel variants of adeAB(C) , which encodes a major tripartite efflux pump in Acinetobacter . The AadT pump conferred decreased susceptibility to at least eight diverse antimicrobials, including antibiotics erythromycin, tetracycline; biocides chlorhexidine; and dyes ethidium bromide and DAPI. These results show that AadT is a new determinant in the Acinetobacter resistance arsenal and may cooperate with variants of AdeAB(C).