The evolutionary “success” of the genus Brucella depends on the ability to persist both in the environment as well as inside of even activated macrophages of the animal host. For that, the Brucellae produce catalase and superoxide dismutase to defend against oxidative stress. Since the deletion of the mglA gene in the B. abortus S19 vaccine strain resulted not only in an increased tolerance to H₂O₂ but also in the induction of cytokines in macrophages, we here investigated the effect of oxidative stress (Fe²⁺ and H₂O₂) on the survival of B. abortus S19 and the isogenic B. abortus S 19 ∆mglA 3.14 deletion mutant in comparison with B. neotomae 5K33, Brucella strain 83/13, and B. microti CCM4915. These Brucellae belong to different phylogenetic clades and show characteristic differences in the mgl-operon. From the various Brucellae tested, B. abortus S19 showed the highest susceptibility to oxidative stress and the lowest ability to survive inside of murine macrophages. B. abortus S19 ∆mglA 3.14 as well as B. neotomae, which also belongs to the classical core clade of Brucella and lacks the regulators of the mgl-operon, presented the highest degree of tolerance to H₂O₂ but not in the survival in macrophages. The latter was most pronounced in case of an infection with B. 83/13 and B. microti CCM4915. The various Brucellae investigated here demonstrate significant differences in tolerance against oxidative stress and different survival in murine macrophages, which, however, do not correlate directly.

布鲁氏菌属的进化“成功”取决于在环境中以及在动物宿主活化的巨噬细胞内部的持续能力。为此，布鲁氏菌产生过氧化氢酶和超氧化物歧化酶来抵御氧化应激。由于B. abortus S19疫苗株中mglA基因的缺失不仅导致对 H ₂ O _{2 的}耐受性增加，而且还导致巨噬细胞中细胞因子的诱导，我们在这里研究了氧化应激（Fe ²⁺和H ₂ O ₂ ) 对B. abortus S19的存活和同基因B. abortus S 19 ∆mglA 3.14缺失突变体与B. neotomae 5K33、布鲁氏菌菌株 83/13和B. microti CCM4915 相比。这些布鲁氏菌属于不同的系统发育进化枝，在 mgl 操纵子中表现出特征差异。从测试的各种布鲁氏菌中，B. abortus S19对氧化应激的敏感性最高，在鼠巨噬细胞内生存的能力最低。B. abortus S19 ∆mglA 3.14以及B. neotomae，也属于布鲁氏菌的经典核心进化枝并且缺乏mgl-操纵子的调节剂，对H ₂ O ₂表现出最高程度的耐受性，但在巨噬细胞中的存活率方面没有表现出最高程度的耐受性。后者在感染B. 83/13和B. microti CCM4915 的情况下最为明显。此处研究的各种布鲁氏菌证明了小鼠巨噬细胞对氧化应激的耐受性和不同存活率的显着差异，然而，这并不直接相关。