AUTHOR=Mindlin Sofia , Beletsky Alexey , Mardanov Andrey , Petrova Mayya 

TITLE=Adaptive dif Modules in Permafrost Strains of Acinetobacter lwoffii and Their Distribution and Abundance Among Present Day Acinetobacter Strains

JOURNAL=Frontiers in Microbiology

VOLUME=10

YEAR=2019

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2019.00632

DOI=10.3389/fmicb.2019.00632

ISSN=1664-302X

ABSTRACT=<p>The <italic>dif</italic>/Xer system of site-specific recombination allows resolution of chromosomal dimers during bacterial DNA replication. Recently, it was also shown to be involved in horizontal transfer of a few known Xer-dependent mobile elements. Here, we show that plasmids of various <italic>Acinetobacter</italic> species, including clinically important strains, often contain multiple p<italic>dif</italic> sites that are mainly located within their accessory regions. Chromosomes of <italic>Acinetobacter</italic> strains may also contain additional <italic>dif</italic> sites, and their similarity with plasmid p<italic>dif</italic> sites is higher than with the main chromosomal site <italic>dif1</italic>. We further identify putative mobile genetic elements containing p<italic>dif</italic> sites on both flanks of adaptive genes and analyze their distribution in <italic>Acinetobacter</italic> species. In total, we describe seven mobile elements containing genes with various adaptive functions from permafrost strains of <italic>A. lwoffii</italic> group. All of them are also spread in modern plasmids of different <italic>Acinetobacter</italic> species including <italic>A. baumannii</italic>. We could not detect p<italic>dif</italic> sites and corresponding mobile elements in closely related bacterial genera, including <italic>Psychrobacter</italic> and <italic>Moraxella</italic>. Thus, the widespread distribution of <italic>dif</italic> modules is a characteristic feature of <italic>Acinetobacter</italic> species and may contribute to their high adaptability both in the environment and in the clinic.</p>