Diversity and Mobility of Integrative and Conjugative Elements in Bovine Isolates of S treptococcus agalactiae , S. dysgalactiae subsp. dysgalactiae , and S. uberis

Abstract

Bovine isolates of Streptococcus agalactiae (n ‫؍‬ 76), Streptococcus dysgalactiae subsp. dysgalactiae (n ‫؍‬ 32), and Streptococcus uberis (n ‫؍‬ 101) were analyzed for the presence of different integrative and conjugative elements (ICEs) and their association with macrolide, lincosamide, and tetracycline resistance. The diversity of the isolates included in this study was demonstrated by multilocus sequence typing for S. agalactiae and pulsedfield gel electrophoresis for S. dysgalactiae and S. uberis. Most of the erythromycin-resistant strains carry an ermB gene. Five strains of S. uberis that are resistant to lincomycin but susceptible to erythromycin carry the lin(B) gene, and one has both linB and lnuD genes. In contrast to S. uberis, most of the S. agalactiae and S. dysgalactiae tetracycline-resistant isolates carry a tet(M) gene. A tet(S) gene was also detected in the three species. A Tn916-related element was detected in 30 to 50% of the tetracycline-resistant strains in the three species. Tetracycline resistance was successfully transferred by conjugation to an S. agalactiae strain. Most of the isolates carry an ICE integrated in the rplL gene. In addition, half of the S. agalactiae isolates have an ICE integrated in a tRNA lysine (tRNA Lys ) gene. Such an element is also present in 20% of the isolates of S. dysgalactiae and S. uberis. A circular form of these ICEs was detected in all of the isolates tested, indicating that these genetic elements are mobile. These ICEs could thus also be a vehicle for horizontal gene transfer between streptococci of animal and/or human origin.

Genetic diversity and virulence genes in Streptococcus uberis strains isolated from bovine mastitis

“…This indicates high population diversity among the S. uberis strains isolated from bovine mastitis in accordance with previous studies (LASAGNO et al, 2011;HAENNI et al, 2010;REINOSO et al, 2015;WANG et al, 1999WANG et al, , 2013. As discussed above, this diversity could be associated with environmental adaptations of this pathogen and its capacity to infect cows.…”

Identification of Group G Streptococcal Isolates from Companion Animals in Japan and Their Antimicrobial Resistance Patterns

“…, and tet(S), in ML-and TET-resistant strains, respectively, was confirmed by PCR, as previously described (18,19). We also confirmed the sequences of the resistance determinants of several isolates that were positive for the targeted genes.…”

In vitro antimicrobial susceptibility and genetic resistance determinants of Streptococcus agalactiae isolated from mastitic cows in Brazilian dairy herds

“…Associations between tet and erm genes, owing to their presence in the same mobile genetic element, have been described several times in relation to Streptococcus pyogenes and Streptococcus pneumoniae, but only rarely with respect to S. agalactiae (HAENNI et al, 2010;VARALDO et al, 2009), and their prevalence in this latter may be underestimated.…”