MFS antiporter that does not display functional linkage as drug transporter and performs functions that significantly affect biofilm development and virulence. No substrate for transport has been identified yet, but plays an important role in the growth in the host. In contrast to QDR1 and QDR2, does not accumulate in membrane rafts and shows uniform distribution at the cell membrane. Expression is repressed by HAP43. Leads to defects in biofilm architecture and attenuated virulence. Belongs to the major facilitator superfamily. CAR1 family.