Publikationsdatenbank

Excision and integration of unconventional circularizable structures involving the erm(B) gene in enterococci (2022)

Art

Zeitschriftenartikel / wissenschaftlicher Beitrag

Autoren

Shan, Xinxin

Yao, Hong

Schwarz, Stefan (WE 7)

Li, Dexi

Li, Xin-Sheng

Du, Xiang-Dang

Quelle

Veterinary microbiology : an international journal

Bandzählung: 273

Seiten: Artikel 109542

ISSN: 0378-1135

Sprache

Englisch

Verweise

URL (Volltext): https://www.sciencedirect.com/science/article/pii/S0378113522002127

DOI: 10.1016/j.vetmic.2022.109542

Pubmed: 35969915

Kontakt

Institut für Mikrobiologie und Tierseuchen

Robert-von-Ostertag-Str. 7-13
14163 Berlin
+49 30 838 51843 / 66949
mikrobiologie@vetmed.fu-berlin.de

Abstract / Zusammenfassung

Traditionally, insertion sequences (ISs) play a major role in disseminating antimicrobial resistance genes (ARGs) in bacteria through transposition and translocation, forming regions that contain multiple ARGs flanked by single or multiple copies of IS. In addition, unconventional circularizable structures (UCSs), lacking recombinase genes but being surrounded by directly repeated sequences (DRs) of various sizes which do not contain transposase genes, were reported to be involved in the dissemination of ARGs. In this study, a novel UCS was identified on plasmid pE508-2 in E. faecalis E508, which carried a 24,411 bp multiresistance gene cluster, consisting of the resistance genes aphA3, lnu(B), lsa(E), spw, aac(A)-aph(D), lnu(B), dfrG, and two copies of aadE flanked by copies of erm(B). PCR assays revealed that three types of UCSs with lengths of 7235, 16,437, and 23,673 bp were formed, each of which contained the respective resistance genes and one copy of erm(B). Using erm(B)-negative and -positive strains, we demonstrated that erm(B)-carrying UCSs failed to transfer into an erm(B)-negative strain, but could integrate into an erm(B)-positive strain in a new site adjacent to a pre-existing erm(B) gene by natural transformation. Database searches revealed that erm(B)-flanked multiresistance gene regions, which might be able to form the respective UCSs, are present among various bacteria from different sources in various countries. In summary, this study experimentally demonstrated the excision and integration of UCS involving structures that include erm(B). The widespread presence of these UCSs in various Gram-positive bacteria highlights its role in the dissemination of ARGs among bacterial pathogens.