AUTHOR=Chen Li , Huang Jinhu , Huang Xinxin , He Yuping , Sun Junjie , Dai Xingyang , Wang Xiaoming , Shafiq Muhammad , Wang Liping 

TITLE=Horizontal Transfer of Different erm(B)-Carrying Mobile Elements Among Streptococcus suis Strains With Different Serotypes

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.628740

DOI=10.3389/fmicb.2021.628740

ISSN=1664-302X

ABSTRACT=<p>Macrolide-resistant <italic>Streptococcus suis</italic> is highly prevalent worldwide. The acquisition of the <italic>erm</italic>(B) gene mediated by mobile genetic elements (MGEs) in particular integrative and conjugative elements (ICEs) is recognized as the main reason for the rapid spread of macrolide-resistant streptococcal strains. However, knowledge about different <italic>erm</italic>(B)-carrying elements responsible for the widespread of macrolide resistance and their transferability in <italic>S. suis</italic> remains poorly understood. In the present study, two <italic>erm</italic>(B)- and <italic>tet</italic>(O)-harboring putative ICEs, designated as ICE<italic>Ssu</italic>YSB17_<italic>rplL</italic> and ICE<italic>Ssu</italic>YSJ15_<italic>rplL</italic>, and a novel <italic>erm</italic>(B)- and <italic>aadE-spw</italic>-like-carrying genomic island (GI), named GI<italic>Ssu</italic>JHJ17_<italic>rpsI</italic>, were identified to be excised from the chromosome and transferred among <italic>S. suis</italic> strains with different serotypes. ICE<italic>Ssu</italic>YSB17_<italic>rplL</italic> and ICE<italic>Ssu</italic>YSJ15_<italic>rplL</italic> were integrated downstream the <italic>rplL</italic> gene, a conserve locus of the ICE<italic>Sa</italic>2603 family. GI<italic>Ssu</italic>JHJ17_<italic>rpsI</italic>, with no genes belonging to the conjugation module, was integrated into the site of <italic>rpsI</italic>. All transconjugants did not exhibit obvious fitness cost by growth curve and competition assays when compared with the recipient. The results demonstrate that different <italic>erm</italic>(B)-carrying elements were presented and highlight the role of these elements in the dissemination of macrolide resistance in <italic>S. suis</italic>.</p>