Zinc transporter systems in bacteria [2, 9, 19,20,21,22]. Under zinc-replete conditions, membrane transport based on the P-type ATPase, CDF-type and RND-type families participates in zinc distribution. They work together to maintain zinc homeostasis in the cell. With sufficient zinc supplementation, bacteria control the cellular zinc concentration by a low-affinity absorption system, such as Pit and ZupT. Under zinc-limiting conditions, transporters of the high-affinity absorption system are induced and used to recruit Zn2+ against zinc deficiency, including ZnuACB, ZitB, ZnuD, etc.