Metal acquisition and virulence in Brucella

Abstract

Similar to other bacteria, Brucella strains require several biologically essential metals for their survival in vitro and in vivo. Acquiring sufficient levels of some of these metals, particularly iron, manganese and zinc, is especially challenging in the mammalian host, where sequestration of these micronutrients is a well-documented component of both the innate and acquired immune responses. This review describes the Brucella metal transporters that have been shown to play critical roles in the virulence of these bacteria in experimental and natural hosts.

Fig. 1

Iron transporters in Brucella. Abbreviations: OM, outer membrane; CM, cytoplasmic membrane.

Fig. 2

Nickel, zinc, manganese, magnesium and cobalt transporters in Brucella. Abbreviations: OM, outer membrane; CM, cytoplasmic membrane. MgtC is not shown in this figure because its precise role in Mg²⁺ transport is not known (Günzel et al., 2006; Alix and Blanc-Potard, 2007).

Fig. 3

Brucella genes experimentally linked to virulence in pregnant ruminants and mice. Virulence in pregnant ruminants is measured by bacterial colonization of the dam and fetus and fetal pathology (e.g. abortion or the birth of a weak kid or calf). Virulence in mice is measured by chronic colonization of the spleen.