Open AccessCharacterization of tetA ‐like gene encoding for a major facilitator superfamily efflux pump in Streptococcus thermophilus
Author(s) -
Arioli Stefania,
Guglielmetti Simone,
Amalfitano Stefano,
Viti Carlo,
Marchi Emmanuela,
Decorosi Francesca,
Giovannetti Luciana,
Mora Diego
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 - 10.1111/1574-6968.12449
Subject(s) - major facilitator superfamily , streptococcus thermophilus , efflux , ethidium bromide , biology , microbiology and biotechnology , operon , gene , population , genetics , mutant , bacteria , lactobacillus , dna , demography , sociology
Efflux pumps are membrane proteins involved in the active extrusion of a wide range of structurally dissimilar substrates from cells. A multidrug efflux pump named TetA belonging to the major facilitator superfamily ( MFS ) of transporters was identified in the Streptococcus thermophilus DSM 20617 T genome. The tetA ‐like gene was found in the genomes of a number of S. thermophilus strains sequenced to date and in Streptococcus macedonicus ACA ‐ DC 198, suggesting a possible horizontal gene transfer event between these two Streptococcus species, which are both adapted to the milk environment. Flow cytometry (single‐cell) analysis revealed bistable TetA activity in the S. thermophilus population, and tetA ‐like gene over‐expression resulted in a reduced susceptibility to ethidium bromide, tetracycline, and other toxic compounds even when the efflux pump was over‐expressed in a strain naturally lacking tetA‐ like gene.