Open AccessMinocycline resistance in an oral Streptococcus infantis isolate is encoded by tet (S) on a novel small, low copy number plasmid
Author(s) -
Ciric Lena,
Brouwer Michael S. M.,
Mullany Peter,
Roberts Adam P.
Publication year - 2014
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/1574-6968.12410
Subject(s) - plasmid , biology , transposable element , antitoxin , minocycline , microbiology and biotechnology , gene , genetics , mutant , toxin , antibiotics
We have determined the genetic basis of minocycline resistance in a strain of S treptococcus infantis isolated from a healthy human oral cavity. We demonstrate that tet (S), identical to tet (S) found on the enterococcal conjugative transposon Tn 6000 , is responsible for the observed resistance. The gene is located on a small, low copy number plasmid and is flanked by IS 1216 elements. The tet (S) gene is capable of excising from the plasmid together with one of the IS 1216 elements. The plasmid contains a putative toxin/antitoxin system related to relBE . Deletion of the toxin, relE , did not result in plasmid instability but did increase the fitness of the mutant compared to the wild‐type strain.