The relative expression of mptABCD operon, glpQ, pde, rpoN, mptR and gap-1 was studied by reverse transcription combined with the real time polymerase chain reaction to understand the role of each gene in resistance/sensitivity of Enterococcus faecalis to class IIa bacteriocins such as recombinant divercin V41 (DvnRV41). Comparative critical threshold methods in presence or absence of DvnRV41 were then used to determine the level of expression of each gene cited above. In the presence of DvnRV41, the rpoN and glpQ genes were down-regulated, mptR, mptC, gap-1 and pde genes were up-regulated, whilst expression of mptB and mptD genes remained unmodified.