Origin, Phylogeny, and Transmission of the Epidemic Clone ST208 of Carbapenem-Resistant Acinetobacter baumannii on a Global Scale

Abstract

ST208 as one of the most prevalent lineages of CRAB has caused several difficult-to-treat infections and outbreaks around the world. However, few studies have focused on evaluating the genetic background differences of ST208 A. baumannii isolated from very distant geographic regions.

Outbreak of High-risk XDR CRAB of International Clone 2 (IC2) in Rio Janeiro, Brazil

“…Overall, this suggests that there are at least three XDR CRAB IC2/ST2 sub-lineages occurring in Brazil simultaneously. Interestingly, the Brazilian genomes did not cluster with other IC2/ST2 genomes from South America, suggesting that these Brazilian CRAB IC2/ST2 strains originate from countries in Europe, North America, and/or Asia where CRAB IC2 is prevalent [1]. Although we did not observe relevant differences in the genetic composition of these three Brazilian clusters, except for the capsule, they could be evolving into specific lineages, as seems to have occurred for other South American ICs [27].…”

“…CRAB IC2 is the most prevalent A. baumannii causing outbreaks worldwide [8], however, interestingly, reports of IC2/ST2 are scarce in South America [7]. In fact, in a recent study (2022) on the origin, phylogeny, and transmission of IC2 on a global scale, IC2 from South America was not analyzed [1]. Furthermore, the study concluded that IC2 (ST208/Oxford scheme) may have originated in North America and subsequently evolved into two clades [1].…”

“…In fact, in a recent study (2022) on the origin, phylogeny, and transmission of IC2 on a global scale, IC2 from South America was not analyzed [1]. Furthermore, the study concluded that IC2 (ST208/Oxford scheme) may have originated in North America and subsequently evolved into two clades [1]. Interestingly, in the same year (2022), the first CRAB IC2 outbreak was reported in Brazil (São Paulo city), and an IC2/ST2 genome from Brazil became available [9].…”

“…Acinetobacter baumannii represents a critically opportunistic pathogen worldwide, with rapid dissemination in clinical settings, being associated with various types of infections [1]. This species is a member of the ESKAPE group (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.…”

“…Within IC2, there is a great diversity of sub-lineages with different sequence types (ST), with ST2 (Pasteur scheme) being the most prevalent [5]. Indeed, A. baumannii presents high levels of recombination events, resulting in distinct lineages, even within the same ST [1]. The presence of divergent IC2 strains and their increasing prevalence in clinical settings support the continued adaptation of this lineage to the hospital environment [6].…”