The plasmid diversity ofAcinetobacter bereziniaeHPC229 provides clues on the ability of the species to thrive on both clinical and environmental habitats

Abstract

<jats:title>Abstract</jats:title><jats:p><jats:italic>Acinetobacter bereziniae</jats:italic> is an environmental microorganism with increasing clinical incidence, and may thus provide a model for a bacterial species bridging the gap between the environment and the clinical setting. <jats:italic>A. bereziniae</jats:italic> plasmids have been poorly studied, and their characterization could offer clues on the causes underlying the leap between these two radically different habitats. Here we characterized the whole plasmid content of <jats:italic>A. bereziniae</jats:italic> HPC229, a clinical strain previously reported to harbor a 44-kbp plasmid, pNDM229, conferring carbapenem and aminoglycoside resistance. We identified five extra plasmids in HPC229 ranging from 114 to 1.3 kbp, including pAbe229-114 (114 kbp) encoding a MOB<jats:sub>P111</jats:sub> relaxase and carrying heavy metal resistance, a bacteriophage defense BREX system and four different toxin-antitoxin (TA) systems. Two other replicons, pAbe229-15 (15.4 kbp) and pAbe229-9 (9.1 kbp), both encoding MOB<jats:sub>Q1</jats:sub> relaxases and also carrying TA systems, were found. The three latter plasmids contained <jats:italic>Acinetobacter</jats:italic> Rep_3 superfamily replication initiator protein genes. HPC229 also harbors two smaller plasmids, pAbe229-4 (4.4 kbp) and pAbe229-1 (1.3 kbp), the former bearing a ColE1-type replicon and a TA system, and the latter lacking known replication functions. Comparative sequence analyses against deposited <jats:italic>Acinetobacter</jats:italic> genomes indicated that the above five HPC229 plasmids were unique, although some regions were also present in other of these genomes. The transfer, replication, and adaptive modules in pAbe229-15, and the stability module in pAbe229-9, were bordered by sites potentially recognized by XerC/XerD site-specific tyrosine recombinases, thus suggesting a potential mechanism for their acquisition. The presence of Rep_3 and ColE1-based replication modules, different <jats:italic>mob</jats:italic> genes, distinct adaptive functions including resistance to heavy metal and other environmental stressors, as well as antimicrobial resistance genes, and a high content of XerC/XerD sites among HPC229 plasmids provide evidence of substantial links with bacterial species derived from both environmental and clinical habitats.</jats:p>

Dynamic state of plasmid genomic architectures resulting from XerC/D-mediated site-specific recombination in Acinetobacter baumannii Rep_3 superfamily resistance plasmids carrying blaOXA-58- and TnaphA6-resistance modules

“…These inferences indicated that Rep_3 plasmids carrying pXerC/D-bounded genes were already present in the A. baumannii population before the massive anthropogenic introduction of antimicrobials by the middle of last century (Antunes et al, 2014;Baquero et al, 2021). GGTGTA cr sequences can also be found among 6 out of the 17 non-identical pXerC/D sites identified by us among Ab242/Ab825 plasmids (Cameranesi et al, 2018), and between many of the multiple pXerC/D sites described in other plasmids of many Acinetobacter (and even non-Acinetobacter) strains isolated in different periods and from different sources, both clinical and environmental (Fu et al, 2014;Blackwell and Hall, 2017;Brovedan et al, 2019;Matos et al, 2019;Mindlin et al, 2019;Balalovski and Grainge, 2020;Bonnin et al, 2020;Salgado-Camargo et al, 2020;Wang et al, 2020;Alattraqchi et al, 2021;Hamidian et al, 2021;Liu et al, 2021;Jones et al, 2022). Although it remains to be established what other factors influence the feasibility (or reversibility) of SSR events between sites sharing identical cr sequences, it is likely that some of these sites participate in the remodeling and evolution of Acinetobacter plasmids in the eventuality that they collide in the same cell, with the concomitant accelerated dissemination of the resistance determinants they bound.…”

Azolla filiculoides L. as a source of metal-tolerant microorganisms

“…These authors suggested that the presence of plasmids is one of the sources of genetic diversity and that frequently, heavy metal resistance in acinetobacters is plasmid encoded [57]. Other researchers also showed multiple plasmids (plasmidome) encoding resistance to Hg, Cr, Co/ Zn/Cd, Ni, and As in Acinetobcter strains and suggested that these plasmidomes can provide resistance to heavy metals in both environmental and clinical habitats [58][59][60]. El-Sayed [61] determined dual expressions of heavy metal and antibiotic resistance from A. baumannii strain HAF-13, a potential seed for decommissioning of sites polluted with industrial effluents rich in heavy metals, since this isolate will be able to withstand in situ antibiosis that may prevail in such ecosystems.…”