Prevalence, diversity and transferability of the Tn916-Tn1545 family ICE in oral streptococci. Issue 1 (1st January 2021) - Lunde, Tracy Munthali
ABSTRACT: Background : The Tn 916 -Tn 1545 family of Integrative Conjugative Elements (ICE) are mobile genetic elements (MGEs) that play a role in the spread of antibiotic resistance genes. The Tn 916 harbors the tetracycline resistance gene tet (M) and it has been reported in various bacterial species. The increase in the levels of tetracycline resistance among oral streptococci is of great concern primarily due to the abundance of these species in the oral cavity and their ability to act as reservoirs for antibiotic resistance genes.Methods : In the current study, we screened 100 Norwegian clinical oral streptococcal isolates for the presence and diversity of the Tn 916 -Tn 1545 family. In addition, we investigated the transferability the elements, and the associated transfer frequencies.Results : We observed that 21 isolates harboured the Tn 916 -Tn 1545 family and that two of these elements were the novel Tn 6815 and Tn 6816 . The most prevalent member of the Tn 916 -Tn 1545 family observed in the Norwegian clinical oral streptococcal isolates was the wild type Tn 916 .Conclusion : The detection of other members of this family of ICE and varying transfer frequencies suggests high versatility of the Tn 916 element in oral streptococci in Norway.