Dissemination of ArmA- and OXA-23-co-producing Acinetobacter baumannii Global Clone 2 in Switzerland, 2020 –2021

AbstractFollowing the observation of an increased number of isolation of OXA-23- and ArmA-producingAcinetobacter baumannii at the national level, our aim was to evaluate whether some given clone(s) might actually be spreading and/or emerging in Switzerland. To evaluate this possibility, our study investigated and characterized allA. baumannii isolates harboring both theblaOXA-23 andarmA genes that had been collected at the Swiss National Reference Center for Emerging Antibiotic Resistance (NARA) from 2020 to 2021. Most isolates were obtained from infections rather than colonization with the majority being obtained from respiratory specimens. Pulsed-field gel electrophoresis (PFGE) analysis of 56 isolates identified nine profiles. Then, whole-genome sequencing that was performed on a subset of 11 isolates including at least one representative isolate of each PFGE profile identified three STs; one each of ST25 and ST1902, and nine ST2 (a member of Global Clone 2 (GC-2). TheblaOXA-23 gene was always found embedded within Tn2006 structures, as commonly described with GC-2 (ST2) isolates. Susceptibility testing showed that most of those isolates, despite being highly resistant to all carbapenems and all aminoglycosides, remained susceptible to colistin (94.6%), sulbactam-durlobactam (87.5%), and cefiderocol (83.9% or 91.1% according to EUCAST or CLSI breakpoints, respectively). Overall, this study identified that theA. baumannii co-producing OXA-23 and ArmA are increasing in incid...
Source: European Journal of Clinical Microbiology and Infectious Diseases - Category: Microbiology Source Type: research