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Front. Microbiol. | doi: 10.3389/fmicb.2019.01909

Proteomic Analysis Reveals a Biofilm-like Behavior of Planktonic Aggregates of Staphylococcus epidermidis grown under Environmental Pressure/Stress

 Marta Bottagisio1*,  Alessio Soggiu2*, Cristian Piras2,  Alessandro Bidossi1, Viviana Greco3, Luigi Bonizzi2,  Paola Roncada4 and  Arianna B. Lovati1
  • 1Istituto Ortopedico Galeazzi (IRCCS), Italy
  • 2University of Milan, Italy
  • 3Fondazione Policlinico Universitario A. Gemelli, Università Cattolica del Sacro Cuore, Italy
  • 4Università degli studi Magna Græcia di Catanzaro, Italy

Prosthetic joint replacement failure has a huge impact on quality of life and hospitalization costs. A leading cause of prosthetic joint infection is bacteria-forming biofilm on the surface of orthopedic devices. Staphylococcus epidermidis is an emergent, low-virulence pathogen implicated in chronic infections, barely indistinguishable from aseptic loosening when embedded in a mature matrix. The literature is scarce on the behavior of quiescent S. epidermidis in mature biofilms. To fill this gap, we performed comparative analysis of the whole proteomic profiles of two methicillin-resistant S. epidermidis strains growing in planktonic and in sessile form to investigate the molecular mechanisms underlying biofilm stability. After 72-h culture of biofilm-forming S. epidermidis, overexpression of proteins involved in the synthesis of nucleoside triphosphate and polysaccharides was observed, whereas planktonic bacteria expressed proteins linked to stress and anaerobic growth. Cytological analysis was performed to determine why planktonic bacteria unexpectedly expressed proteins typical of sessile culture. Images evidenced that prolonged culture under vigorous agitation can create a stressful growing environment that triggers microorganism aggregation in a biofilm-like matrix as a mechanism to survive harsh conditions. The choice of a unique late time point provided an important clue for future investigations into the biofilm-like behavior of planktonic cells. Our preliminary results may inform comparative proteomic strategies in the study of mature bacterial biofilm. Finally, there is an increasing number of studies on the aggregation of free-floating bacteria embedded in an extracellular matrix, prompting the need to gain further insight into this mode of bacterial growth.

Keywords: Proteomics, Methicillin-Resistant Staphylococcus epidermidis (MRSE), Biofilm, planktonic, Sessile, Prosthetic joint infections, Orthopedics

Received: 05 Feb 2019; Accepted: 05 Aug 2019.

Edited by:

Manuel Simões, Faculty of Engineering, University of Porto, Portugal

Reviewed by:

Airat R. Kayumov, Kazan Federal University, Russia
Anastasia Spiliopoulou, General University Hospital of Patras, Greece  

Copyright: © 2019 Bottagisio, Soggiu, Piras, Bidossi, Greco, Bonizzi, Roncada and Lovati. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Dr. Marta Bottagisio, Istituto Ortopedico Galeazzi (IRCCS), Milan, Italy, marta.bottagisio@grupposandonato.it
Dr. Alessio Soggiu, University of Milan, Milan, 20122, Lombardy, Italy, alessio.soggiu@unimi.it