AUTHOR=Huang Jinhu , Liang Yuan , Guo Dawei , Shang Kexin , Ge Lin , Kashif Jam , Wang Liping 

TITLE=Comparative Genomic Analysis of the ICESa2603 Family ICEs and Spread of erm(B)- and tet(O)-Carrying Transferable 89K-Subtype ICEs in Swine and Bovine Isolates in China

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.00055

DOI=10.3389/fmicb.2016.00055

ISSN=1664-302X

ABSTRACT=<p>Integrative and conjugative elements (ICEs) of the ICE<italic>Sa</italic>2603 family have been isolated from several species of <italic>Streptococcus</italic> spp.; however, the comparative genomic and evolutionary analyses of these particular ICEs are currently only at their initial stages. By investigating 13 ICEs of the ICE<italic>Sa</italic>2603 family and two ICE<italic>Sa</italic>2603 family-like ICEs derived from diverse hosts and locations, we have determined that ICEs comprised a backbone of 30 identical syntenic core genes and accessory genes that were restricted to the intergenic sites or the 3′-end of the non-conserved domain of core genes to maintain its function. ICE<italic>Sa</italic>2603 family integrase Int<sub>ICE</sub><sub><italic>Sa</italic></sub><sub>2603</sub> specifically recognized a 15-bp <italic>att</italic> sequence (TTATTTAAGAGTAAC) at the 3′-end of <italic>rplL</italic>, which was highly conserved in genus <italic>Streptococcus</italic>. Phylogenetic analyses suggest that extensive recombination/insertion and the occurrence of a hybrid/mosaic in the ICE<italic>Sa</italic>2603 family were responsible for the significant increase in ICE diversity, thereby broadening its host range. Approximately 42.5 and 38.1% of the tested <italic>Streptococcus suis</italic> and <italic>Streptococcus agalactiae</italic> clinical isolates respectively contained ICE<italic>Sa</italic>2603 family Type IV secretion system (T4SS) genes, and 80.5 and 62.5% of which also respectively carried <italic>int</italic><sub>ICE</sub><sub><italic>Sa</italic></sub><sub>2603</sub>, indicating that ICE<italic>Sa</italic>2603 family is widely distributed across these bacteria. Sequencing and conjugation transfer of a novel sequence type ST303 clinical <italic>S. suis</italic> isolate HB1011 demonstrated that the 89K-subtype ICE<italic>Ssu</italic>HB1011 retained its transferrable function, thereby conferring tetracycline and macrolide resistance.</p>