Salmonella Biofilms Tolerate Hydrogen Peroxide by a Combination of Extracellular Polymeric Substance Barrier Function and Catalase Enzymes.
Salmonella Biofilms Tolerate Hydrogen Peroxide by a Combination of Extracellular Polymeric Substance Barrier Function and Catalase Enzymes.
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DOI：
10.3389/fcimb.2021.683081
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发表时间：
2021
影响因子：
5.7
通讯作者：
Gunn JS
中科院分区：
文献类型：
--
作者：
Hahn MM;González JF;Gunn JS
沙门氏菌伤寒亚种（S。伤寒）引起慢性胆囊感染依赖于胆固醇结石上生物膜的生长。非伤寒沙门氏菌（如S.鼠伤寒杆菌）也利用生物膜状态在宿主和环境中持续存在。在慢性感染期间，病原体如何保持对宿主反应的抵抗力，特别是氧化应激，目前还知之甚少。以前的实验表明，S。伤寒和沙门氏菌。鼠伤寒沙门氏菌生物膜耐受过氧化氢（H2 O2），但生物膜细胞外聚合物（EPS）O抗原胶囊，colanic酸或Vi抗原的突变降低了耐受性。在这里，生物膜介导的耐受性氧化应激进行了研究，使用EPS和过氧化氢酶突变体的组合，因为过氧化氢酶是重要的解毒剂H2 O2。使用野生型（WT）细菌与EPS突变体的共培养生物膜，证明了S.鼠伤寒沙门氏菌（S.伤寒杆菌具有群体功能，保护所有生物膜居民细菌，而不仅仅是保护产生EPS的单个细胞。然而，O抗原荚膜突变体的H2 O2耐受性缺陷不能通过与WT细菌共培养来补偿。对于卷曲菌毛，WT和突变株均耐受H2 O2，但出乎意料的是，用H2 O2挑战的共培养的WT/突变生物膜导致两种菌株的致敏，表明这些共培养物中更细微的氧化抗性改变。还检查了三种过氧化氢酶突变体（katE、katG和推定的过氧化氢酶）生物膜，表明katE和katG突变体的生物膜H2 O2耐受性显著降低。生物膜共培养实验表明，过氧化氢酶表现出社区功能。我们进一步假设生物膜耐受H2 O2，因为EPS形成的物理屏障将H2 O2渗透到生物膜中的速度减慢到可以通过生物膜内过氧化氢酶减轻的速度。与WT相比，EPS缺陷型生物膜甚至对低剂量（2.5 mM）H2 O2挑战具有升高的响应，证实EPS缺陷型生物膜的常驻细菌处于更大的压力下并且对H2 O2的保护有限。因此，这些数据提供了一个解释沙门氏菌如何实现耐受H2 O2的EPS介导的屏障和酶解毒的组合。
The ability of Salmonella enterica subspecies enterica serovar Typhi (S. Typhi) to cause chronic gallbladder infections is dependent on biofilm growth on cholesterol gallstones. Non-typhoidal Salmonella (e.g. S. Typhimurium) also utilize the biofilm state to persist in the host and the environment. How the pathogen maintains recalcitrance to the host response, and oxidative stress in particular, during chronic infection is poorly understood. Previous experiments demonstrated that S. Typhi and S. Typhimurium biofilms are tolerant to hydrogen peroxide (H2O2), but that mutations in the biofilm extracellular polymeric substances (EPSs) O antigen capsule, colanic acid, or Vi antigen reduce tolerance. Here, biofilm-mediated tolerance to oxidative stress was investigated using a combination of EPS and catalase mutants, as catalases are important detoxifiers of H2O2. Using co-cultured biofilms of wild-type (WT) bacteria with EPS mutants, it was demonstrated that colanic acid in S. Typhimurium and Vi antigen in S. Typhi have a community function and protect all biofilm-resident bacteria rather than to only protect the individual cells producing the EPSs. However, the H2O2 tolerance deficiency of a O antigen capsule mutant was unable to be compensated for by co-culture with WT bacteria. For curli fimbriae, both WT and mutant strains are tolerant to H2O2 though unexpectedly, co-cultured WT/mutant biofilms challenged with H2O2 resulted in sensitization of both strains, suggesting a more nuanced oxidative resistance alteration in these co-cultures. Three catalase mutant (katE, katG and a putative catalase) biofilms were also examined, demonstrating significant reductions in biofilm H2O2 tolerance for the katE and katG mutants. Biofilm co-culture experiments demonstrated that catalases exhibit a community function. We further hypothesized that biofilms are tolerant to H2O2 because the physical barrier formed by EPSs slows penetration of H2O2 into the biofilm to a rate that can be mitigated by intra-biofilm catalases. Compared to WT, EPS-deficient biofilms have a heighted response even to low-dose (2.5 mM) H2O2 challenge, confirming that resident bacteria of EPS-deficient biofilms are under greater stress and have limited protection from H2O2. Thus, these data provide an explanation for how Salmonella achieves tolerance to H2O2 by a combination of an EPS-mediated barrier and enzymatic detoxification.
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影响因子：
3.1
作者：
Gonzalez-Escobedo, Geoffrey;Gunn, John S.
通讯作者：
Gunn, John S.
影响因子：
3.5
作者：
CHEREPANOV, PP;WACKERNAGEL, W
通讯作者：
WACKERNAGEL, W
影响因子：
3.2
作者：
Crawford, Robert W.;Reeve, Kristin E.;Gunn, John S.
通讯作者：
Gunn, John S.
影响因子：
15.9
作者：
BUCHMEIER, NA;LIBBY, SJ;FANG, FC
通讯作者：
FANG, FC
影响因子：
6.4
作者：
Gonzalez, Juan F.;Kurtz, Jonathan;Gunn, John S.
通讯作者：
Gunn, John S.