Autor(es): Gaio, Vânia Silva ; Lima, Tânia ; Vilanova, Manuel ; Cerca, Nuno ; França, Ângela Maria Oliveira Sousa
Data: 2022
Identificador Persistente: http://hdl.handle.net/1822/75652
Origem: RepositóriUM - Universidade do Minho
Assunto(s): SERP1681; SERP1682; antimicrobial tolerance; biofilms; human blood; human plasma; macrophages; dendritic cells; Science & Technology
The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fcimb.2021.803134/ full#supplementary-material
Staphylococcus epidermidis biofilm cells are characterized by increased antimicrobial tolerance and improved ability to evade host immune system defenses. These features are, in part, due to the presence of viable but non-culturable (VBNC) cells. A previous study identified genes potentially involved in VBNC cells formation in S. epidermidis biofilms, among which SERP1682/1681 raised special interest due to their putative role as a toxinantitoxin system of the mazEF family. Herein, we constructed an S. epidermidis mutant lacking the mazEF genes homologues and determined their role in (i) VBNC state induction during biofilm formation, (ii) antimicrobial susceptibility, (iii) survival in human blood and plasma, and (iv) activation of immune cells. Our results revealed that mazEF homologue did not affect the proportion of VBNC cells in S. epidermidis 1457, refuting the previous hypothesis that mazEF homologue could be linked with the emergence of VBNC cells in S. epidermidis biofilms. Additionally, mazEF homologue did not seem to influence key virulence factors on this strain, since its deletion did not significantly affect the mutant biofilm formation capacity, antimicrobial tolerance or the response by immune cells. Surprisingly, our data suggest that mazEF does not behave as a toxinantitoxin system in S. epidermidis strain 1457, since no decrease in the viability and culturability of bacteria was found when only the mazF toxin homologue was being expressed.
This work was supported by the Portuguese Foundation for Science and Technology (FCT) by the funder project PTDC/BIA-MOL/29553/2017, under the scope of COMPETE2020 (POCI-01-0145-FEDER-029553) and by the strategic funding unit UIDB/04469/2020. VG acknowledges the support of FCT individual fellowship [SFRH/BD/131452/2017].
info:eu-repo/semantics/publishedVersion
