Dataset Information

ICESp2905, the erm(TR)-tet(O) element of Streptococcus pyogenes, is formed by two independent integrative and conjugative elements.

ABSTRACT: In ICESp2905, a widespread erm(TR)- and tet(O)-carrying genetic element of Streptococcus pyogenes, the two resistance determinants are contained in separate fragments inserted into a scaffold of clostridial origin. ICESp2905 (∼65.6 kb) was transferable not only in its regular form but also in a defective form lacking the erm(TR) fragment (ICESp2906, ∼53.0 kb). The erm(TR) fragment was also an independent integrative and conjugative element (ICE) (ICESp2907, ∼12.6 kb). ICESp2905 thus results from one ICE (ICESp2907) being integrated into another (ICESp2906).

SUBMITTER: Giovanetti E

PROVIDER: S-EPMC3256084 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

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ICESp2905, the erm(TR)-tet(O) element of Streptococcus pyogenes, is formed by two independent integrative and conjugative elements.

Giovanetti Eleonora E Brenciani Andrea A Tiberi Erika E Bacciaglia Alessandro A Varaldo Pietro Emanuele PE

Antimicrobial agents and chemotherapy 20111010 1

In ICESp2905, a widespread erm(TR)- and tet(O)-carrying genetic element of Streptococcus pyogenes, the two resistance determinants are contained in separate fragments inserted into a scaffold of clostridial origin. ICESp2905 (∼65.6 kb) was transferable not only in its regular form but also in a defective form lacking the erm(TR) fragment (ICESp2906, ∼53.0 kb). The erm(TR) fragment was also an independent integrative and conjugative element (ICE) (ICESp2907, ∼12.6 kb). ICESp2905 thus results from ...[more]

PMID: 21986826

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Project description:This study was directed at characterizing the genetic elements carrying the methylase gene erm(B), encoding ribosome modification-mediated resistance to macrolide, lincosamide, and streptogramin B (MLS) antibiotics, in Streptococcus pyogenes. In this species, erm(B) is responsible for MLS resistance in constitutively resistant isolates (cMLS phenotype) and in a subset (iMLS-A) of inducibly resistant isolates. A total of 125 erm(B)-positive strains were investigated, 81 iMLS-A (uniformly tetracycline susceptible) and 44 cMLS (29 tetracycline resistant and 15 tetracycline susceptible). Whereas all tetracycline-resistant isolates carried the tet(M) gene, tet(M) sequences were also detected in most tetracycline-susceptible isolates (81/81 iMLS-A and 7/15 cMLS). In 2 of the 8 tet(M)-negative cMLS isolates, erm(B) was carried by a plasmid-located Tn917-like transposon. erm(B)- and tet(M)-positive isolates were tested by PCR for the presence of genes int (integrase), xis (excisase), and tndX (resolvase), associated with conjugative transposons of the Tn916 family. In mating experiments using representatives of different combinations of phenotypic and genotypic characteristics as donors, erm(B) and tet(M) were consistently cotransferred, suggesting their linkage in individual genetic elements. The linkage was confirmed by pulsed-field gel electrophoresis and hybridization studies, and different elements, variably associated with the different phenotypes/genotypes, were detected and characterized by amplification and sequencing experiments. A previously unreported genetic organization, observed in all iMLS-A and some cMLS isolates, featured an erm(B)-containing DNA insertion into the tet(M) gene of a defective Tn5397, a Tn916-related transposon. This new element was designated Tn1116. Genetic elements not previously described in S. pyogenes also included Tn6002, an unpublished transposon whose complete sequence is available in GenBank, and Tn3872, a composite element resulting from the insertion of the Tn917 transposon into Tn916 [associated with a tet(M) gene expressed in some cMLS isolates and silent in others]. The high frequency of association between a tetracycline-susceptible phenotype and tet(M) genes suggests that transposons of the Tn916 family, so far typically associated solely with a tetracycline-resistant phenotype, may be more widespread in S. pyogenes than currently believed.

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Dataset Information

ICESp2905, the erm(TR)-tet(O) element of Streptococcus pyogenes, is formed by two independent integrative and conjugative elements.

Publications

ICESp2905, the erm(TR)-tet(O) element of Streptococcus pyogenes, is formed by two independent integrative and conjugative elements.

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