Characterization of tetA-like gene encoding for a major facilitator superfamily efflux pump in Streptococcus thermophilus.
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.
Department of Food Environmental and Nutritional Sciences (DeFENS), University of Milan, Milan, Italy.
Stefania
S
Arioli
Simone
S
Guglielmetti
Stefano
S
Amalfitano
Carlo
C
Viti
Emmanuela
E
Marchi
Francesca
F
Decorosi
Luciana
L
Giovannetti
Diego
D
Mora
D017920:Antiporters / Q000235:genetics* / Q000378:metabolism*; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004351:Drug Resistance; D004996:Ethidium / Q000633:toxicity; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D048249:Streptococcus thermophilus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D013752:Tetracycline / Q000633:toxicity
D017920:Antiporters; D001426:Bacterial Proteins; D004269:DNA, Bacterial; C079051:tetA protein, Bacteria; D004996:Ethidium; D013752:Tetracycline
MFS efflux pump; Streptococcus thermophilus; antibiotic resistance; lactic acid bacteria