Contribution of catalase to hydrogen peroxide resistance in Enterococcus faecalis

Abstract

Enterococcus faecalis exhibits high resistance to oxidative stress. Several enzymes are responsible for this trait. The role of alkyl hydroperoxide reductase (Ahp), thiol peroxidase (Tpx), and NADH peroxidase (Npr) in oxidative stress defense was recently characterized. Enterococcus faecalis, in contrast to many other streptococci, contains a catalase (KatA), but this enzyme can only be formed when the bacterium is supplied with heme. We have used this heme dependency of catalase activity and mutants deficient in KatA and Npr to investigate the role of the catalase in resistance against exogenous and endogenous hydrogen peroxide stress. The results demonstrate that in the presence of environmental heme catalase contributes to the protection against toxic effects of hydrogen peroxide.

Antimicrobial activity of Chlorhexidine, Peracetic acid and Sodium hypochlorite/etidronate irrigant solutions against Enterococcus faecalis biofilms

“…This may be due to the presence of detoxifying enzymes such as peroxidases and catalases (Baureder et al . ). In addition, previous studies reported that PAA action is both time‐ and concentration‐dependent, so that longer exposure times and higher concentrations could show higher antimicrobial activity, similar that of to NaOCl (Guerreiro‐Tanomaru et al .…”

Dysbiosis by neutralizing commensal mediated inhibition of pathobionts

“…Among many other components, blood contains serum, hemin and hemoglobin24 but the hemolytic capacity of pathobionts can also increase their concentration25. It is already described that hemoglobin and hemin have a peroxidase activity172627. P. intermedia and P. gingivalis also generate layers of haems with catalytic activity to degrade the H 2 O 2 using hemin and hemoglobin28.…”

AsrR Is an Oxidative Stress Sensing Regulator Modulating Enterococcus faecium Opportunistic Traits, Antimicrobial Resistance, and Pathogenicity

“…However, this appears a priori in contradiction with the higher susceptiblity of the null-mutant strain to both in vitro oxidative stress and oxidative burst in mouse macrophages. Despite the fact that enterococci possess a kat gene, catalase enzyme can only be formed when heme or manganese is present and these organisms are considered as catalase-negative bacteria [48], [49]. While little is known about mechanisms of oxidative stress response in E. faecium , it has been shown in E. faecalis that peroxidases important for the survival under oxidative stress and into macrophages are Tpx (thiol peroxidase), Npr (NADH peroxidase), and Ahp (alkyl hydroperoxide reductase) [50], so that E. faecium homologs are not upregulated in the Δ asrR mutant.…”