Evidence for a chromosome-borne resistance transposon (Tn916) in Streptococcus faecalis that is capable of "conjugal" transfer in the absence of a conjugative plasmid.

AUTOR(ES)

Franke, A E

RESUMO

Streptococcus faecalis strain DS16 harbors the conjugative hemolysin-bacteriocin plasmid pAD1 (35 megadaltons) and the nonconjugative R-plasmid pAD2 determining resistance to streptomycin, kanamycin, and erythromycin; a tetracycline resistance (Tetr) determinant is located on the chromosome. When strain DS16 was mated (on membrane filters) with the plasmid-free strain JH2-2, Tetr transconjugants could be obtained at a frequency of about 10(-6) per recipient. Analyses of transconjugants showed that some contained the Tetr determinant linked to pAD1. Subsequent studies showed that the Tetr determinant was located on a 10-megaldalton transposon, designated Tn916, which could insert into two hemolysin plasmids: pAM gamma 1 and pOB1. In addition, derivatives of DS16 devoid of pAD1 were capable of transferring Tetr to recipient strains. Transconjugants (plasmid-free) from such matings could subsequently act as donors in the transfer of Tetr. Both transposition and transfer were found to be rec independent.

Documentos Relacionados

• Tn924, a chromosome-borne transposon encoding high-level gentamicin resistance in Enterococcus faecalis.
• Conjugal transfer of transposon Tn916 from Streptococcus faecalis to Mycoplasma hominis.
• Evidence for plasmid- and chromosome-borne multiple nif genes in Rhizobium fredii.
• Transfer of the conjugal tetracycline resistance transposon Tn916 from Streptococcus faecalis to Staphylococcus aureus and identification of some insertion sites in the staphylococcal chromosome.
• Conjugal Transfer of Plasmid-Borne Multiple Antibiotic Resistance in Streptococcus faecalis var. zymogenes