Editorial Commentary: Polymyxin-Resistant Acinetobacter baumannii: Urgent Action Needed

In 2009, the Infectious Diseases Society of America (IDSA) set the acronym ESKAPE, which lists the groups of pathogens that pose the highest threat to patients’ safety and to public health [1], one of which is Acinetobacter baumannii [1].Acinetobacter baumannii is a particularly challenging pathogen because it is associated with a high degree of resistance [2], and it is difficult to eliminate its environmental reservoir in healthcare settings with conventional measures [3]. Carbapenems are considered first-line agents for the treatment of A. baumannii infections [4–6], and therefore the rise of infections due to carbapenem-resistant strains is of particular concern, as outcomes deteriorate significantly when isolates become resistant to all β-lactam options [2, 3, 5–7]. Additionally, carbapenemresistant A. baumannii isolates are often susceptible to only 1 or 2 agents, making them extensively drug-resistant (XDR) pathogens by definition [8]. The incidence of XDR A. baumannii infections is continually rising [9]. For severe XDR A. baumannii infections, polymyxins are frequently used, and are considered by most to be the drugs of choice [4]. In this issue of Clinical Infectious Diseases, Qureshi and colleagues report on a case series of patients with isolation of colistin-resistant carbapenem-resistant A. baumannii [10]. In some of the cases described by the authors, the isolates have become truly pandrug resistant (PDR) with resistance seen to all tested antimicrobials. These infections represent a serious iatrogenic complication of modern healthcare, where patients acquire infections in our healthcare facilities, for which we have no treatment options.