Book of Abstracts of CEB Annual Meeting 2017info:eu-repo/semantics/publishedVersio

Carvalhais, Virgínia Maria Dinis

Cerca, Nuno

Vilanova, Manuel

Vitorino, Rui

Universidade do Minho: RepositoriUM

 61 Towards Staphylococcus epidermidis biofilm dormancy characterization  Virgínia Carvalhais1,2,3, Rui Vitorino2, Manuel Vilanova3, Nuno Cerca1  1CEB - Centre of Biological Engineering, Universidade do Minho, 4710-057 Braga, Portugal Group: BIOFILM | Line: Health Biotechnology and Bioengineering 2QOPNA, Mass Spectrometry Center, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal 3ICBAS – Instituto de Ciências Biomédicas de Abel Salazar, University of Porto, 4050-313 Porto, Portugal  Despite being a common colonizer of human skin and mucosae, Staphylococcus epidermidis has a strong ability to adhere to medical devices surfaces. Therefore, S. epidermidis is among the most common causative agents of biofilm-associated infections. Dormant bacteria may be found among the metabolic heterogeneous cells within biofilms. These cells present a low metabolic activity and contribute to tolerance to the host immune response and antibiotics, and relapsing infections.  We performed an integrative analysis of dormancy within S. epidermidis biofilms, using an in vitro model previously described by our group [1]. We conducted a whole-transcriptome and proteome analysis of biofilms with higher number of dormant bacteria. Our data highlighted that: translation process was decreased in dormancy; transcripts involved in oxidation-reduction processes and proteins involved in catalytic activity and GTPase activity were up-regulated in dormancy; genes involved in the pyruvate metabolism were upregulated in dormancy. Additionally, in order to assess if dormant S. epidermidis biofilms influence the reactivity to host immune system, we carried on an immunoproteomic analysis by evaluating the immunoreactivity pattern to human sera. Interestingly, CodY protein was only reactive to sera in biofilms with higher number of dormant cells and ClpP protein only reactive when dormancy was prevented. Curiously, the ClpP deletion was previously associated with reduced ability to form S. epidermidis biofilms and with reduced virulence in a rat model of biofilm-associated infection [2]. These results may also suggest that magnesium is important to prevent nutrient limitation in in vitro S. epidermidis biofilms. Lastly, the clinical impact of dormancy among S. epidermidis isolates was studied. It was observed that both clinical and commensal isolates were able to develop a dormant state. In parallel, the effect of three different antibiotics against S. epidermidis biofilms with induced and prevented dormancy was assessed. Interestingly, our results point out to the development of a viable but-non culturable state within biofilms exposed to tetracycline and rifampicin, although rifampicin was also causing bacteria death.  Overall, using a multiple combined strategy, it was demonstrated that this dormancy model has a particular transcriptomic and proteomic profile, a distinct interplay with host and a relevant clinical impact.   References [1] Cerca, F, Andrade, F, França, A, Andrade, EB, Ribeiro, A, Almeida, AA, Cerca, N, Pier, G, Azeredo, J, Vilanova, M, Staphylococcus epidermidis biofilms with higher proportions of dormant bacteria induce a lower activation of murine macrophages, Journal of Medical Microbiology 60(Pt 12), 1717-1724, 2011. [2] Wang, C, Li, M, Dong, D, Wang, J, Ren, J, Otto, M, Gao, Q, Role of ClpP in biofilm formation and virulence of Staphylococcus epidermidis, Microbes and Infection 9(11), 1376-1383, 2007. 

Towards Staphylococcus epidermidis biofilm dormancy characterization

http://repositorium.sdum.uminho.pt/bitstream/1822/54966/1/document_47746_1.pdf

Towards Staphylococcus epidermidis biofilm dormancy characterization

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Universidade do Minho: RepositoriUM