Characterization of Tn 5801.Sag , a Variant of Staphylococcus aureus Tn 916 Family Transposon Tn 5801 That Is Widespread in Clinical Isolates of Streptococcus agalactiae

Abstract

Tn5801, originally detected in Staphylococcus aureus Mu50, is a Tn916 family element in which a unique int gene (int 5801 ) replaces the int and xis genes in Tn916 (int 916 and xis 916 ). Among 62 tet(M)-positive tetracycline-resistant Streptococcus agalactiae isolates, 43 harbored Tn916, whereas 19 harbored a Tn5801-like element (Tn5801.Sag, ϳ20.6 kb). Tn5801.Sag was characterized (PCR mapping, partial sequencing, and chromosomal integration) and compared to other Tn5801-like elements. Similar to Tn5801 from S. aureus Mu50, tested in parallel, Tn5801.Sag was unable to undergo circularization and conjugal transfer.

Diversity and Evolution of the Tn 5801-tet (M)-Like Integrative and Conjugative Elements among Enterococcus, Streptococcus, and Staphylococcus

“…CTn-tet(M) elements with the same genetic backbone may carry different determinants associated with resistance (e.g., to bacitracin, lincosamides/streptogramins, and trimethoprim in our study) and/or ISs (IS3, IS4, IS30, IS256, and IS1380 families) which are frequently designated with different numbers in other studies (7,20,49). However, all these variants reflect the dynamics of a basic particular element circulating among bacterial communities.…”

“…To date, only scarce Tn5801-like backbones of a few S. aureus and Streptococcus strains have been identified in separate studies (3,15,(18)(19)(20), which did not analyze the clonal context of the isolates, thus limiting the understanding of the evolvability of this element.…”

“…The B15 variant (also designated Tn5801.Sag) (20) was considered the paradigm of the Tn5801 type and was detected among E. faecalis (this study), E. faecium, and S. agalactiae isolates. Some type B Tn5801 elements shared a deletion of 81 bp in orf17 (B17, B21, and B22 from S. agalactiae; also detected in A3 from E. faecium) or an IS256-like insertion upstream of orf13 (B20, B21, and B22).…”

“…Tn5801 was originally detected in the vancomycin-resistant Staphylococcus aureus (VRSA) clinical strain Mu50 recovered in Japan in 1997 (15), but several studies have documented the presence of platforms highly similar to Tn5801 in early isolates of Streptococcus agalactiae (France, 1953) (1), S. aureus (Denmark, 1963; designated Tn6014) (3), and Clostridium perfringens (United States, 1977; a truncated element designated CW459tet(M)] (16). The diversity of Tn5801-like backbones in a few isolates of different species (3,(17)(18)(19)(20) collected throughout more than 50 years suggests the evolutionary interplay of selective events, horizontal dissemination, and the genetic plasticity of this transposon, allowing its spread in different clonal backgrounds and environments. However, little is known about Tn5801, at either the molecular or the epidemiological level.…”

The New Macrolide-Lincosamide-Streptogramin B Resistance Gene erm (45) Is Located within a Genomic Island in Staphylococcus fleurettii

“…The 11,513-bp island containing erm(45) was flanked by 11-bp direct repeats (DRs) (GAGTGGGAATA) situated within the 3= end of the glutamine amidotransferase (GMP) synthetase housekeeping gene guaA (Fig. 1), a known integration hot spot for genetic islands, transposons, and bacteriophages in different bacterial species (17,18). For instance, identical DRs and guaA integration sites were associated with the pathogenicity islands of staphylococci (SaPIs) SaPIbov1 and SaPIbov2, identified in S. aureus from bovine mastitis milk (19).…”