Subtypes, resistance and virulence platforms in extended-drug resistant Acinetobacter baumannii Romanian isolates

Abstract

Acinetobacter baumannii has emerged worldwide as a dominant pathogen in a broad range of severe infections, raising an acute need for efficient antibacterials. This is the first report on the resistome and virulome of 33 extended drug-resistant and carbapenem-resistant A. baumannii (XDR CRAB) strains isolated from hospitalized and ambulatory patients in Bucharest, Romania. A total of 33 isolates were collected and analyzed using phenotypic antibiotic susceptibility and conjugation assays, PCR, whole-genome sequencing (WGS), pulsed-field gel electrophoresis (PFGE) and MultiLocus Sequence Typing (MLST). All isolates were extensively drug-resistant (XDR), being susceptible only to colistin. The carbapenem resistance was attributed by PCR mainly to blaOXA-24 and blaOXA-23 genes. PFGE followed by MLST analysis demonstrated the presence of nine pulsotypes and six sequence types. WGS of seven XDR CRAB isolates from healthcare-associated infections demonstrated the high diversity of resistance genes repertoire, as well as of mobile genetic elements, carrying ARGs for aminoglycosides, sulphonamides and macrolides. Our data will facilitate the understanding of resistance, virulence and transmission features of XDR AB isolates from Romanian patients and might be able to contribute to the implementation of appropriate infection control measures and to develop new molecules with innovative mechanisms of action, able to fight effectively against these bugs, for limiting the spread and decreasing the infection rate and mortality.

Genetic Configuration of Genomic Resistance Islands in Acinetobacter baumannii Clinical Isolates From Egypt

“…Updates on the genetic background of MDR and XDR A. baumannii are continuously being published from different parts of the world (Hamidian and Nigro, 2019;Gheorghe et al, 2021;Wareth et al, 2021) and from Egypt as well (Hassan et al, 2021;Jalal et al, 2021;Wasfi et al, 2021). However, reports about the association of resistance genes with RIs are relatively scarce.…”

Relationship between the Biofilm-Forming Capacity and Antimicrobial Resistance in Clinical Acinetobacter baumannii Isolates: Results from a Laboratory-Based In Vitro Study

“…In A. baumannii, Ambler Class D (OXA-type carbapenemases: the species possesses an intrinsic β-lactamase gene (bla OXA-51-like ), which is often used for the identification of this species), and Class B (metallo-β-lactamases; MBLs) are the most prevalent, while Class A (serine β-lactamases) enzymes have also been described on occasion [35]. The relevance of these enzymes has increased in recent years (either alone or co-existing with OXA-type enzymes) and represents an important therapeutic conundrum, as there are currently no licensed inhibitors for their inhibition in clinical use [36]. As there is limited clinical experience with novel, innovative β-lactam-type drugs (e.g., ceftazidime/avibactam, imipenem/relebactam, meropenem/vaborbactam, and cefiderocol) for Acinetobacter infections, non-β-lactam-type drugs often need to be administered [37].…”

Colistin and Carbapenem-Resistant Acinetobacter baumannii Aci46 in Thailand: Genome Analysis and Antibiotic Resistance Profiling

“…Interestingly, three genes ( czcA , czcB , and czcC ) encode CzcCBA cobalt/zinc/cadmium efflux RND transporters in PCRAB specific genes. CzcCBA cobalt/zinc/cadmium efflux RND transporters have functions in exporting cations (Co 2+ , Zn 2+ , and Cd 2+ ) from the cytoplasm and confer heavy metal resistance [ 43 , 44 ], and are reported to be associated with the XDR phenotype in A. baumannii [ 45 ]. This efflux system might function in colistin resistance in PCRAB, including Aci46, by exporting colistin and polymyxin (cationic molecules).…”