Yvonne Achermann



Propionibacterium species:  Prevention, diagnosis and treatment

The use of orthopedic implants has been increasing steadily in the last 50 years, but despite considerable technological advances including perioperative antimicrobial prophylaxis, implant-associated infections remain a serious complication. These infections are caused by bacteria in the biofilm on the implant surfaces.

Propionibacteria are bacteria which normally colonize the human skin but they can also cause invasive infections in presence of an implant such as shoulder prosthetic joint infections (Achermann et al., CMR, 2015, Achermann et al., CID in review)

Figure. Shoulder prosthesis joint infection caused by Propionibacterium acnes with abscess formation in an 82-year-old woman 3months after primary shoulder arthroplasty. Shown is clinical presentation (A and B) with sudden swelling and pain above left acromioclavicular joint without radiological signs of osteolysis or loosening of the implant (C and D). P. acnes was cultivated in 2 of 2 joint aspirates, 1 of 3 tissue biopsy specimens, and sonication fluid of the mobile part of the implant (Achermann et al., CMR 2015).

Biofilm formation is a major pathogenic strategy in implant-associated infections caused by Probionibacterium species. Biofilm infections are difficult to treat because biofilm bacteria are protected against antimicrobial agents and the immune system. Treatment of these infections often needs removal of the whole implant combined with a prolonged antibiotic therapy because the infections are chronic. To find a diagnostic marker or a vaccine to prevent biofilm infections caused by P. acnes, we identified 24 upregulated proteins that were immunogenic in either planktonic, biofilm, or both modes of growth using rabbit serum from infected animals with P. acnes (Achermann et al., Clin Vaccine Immunol 2015). A preventive vaccine or an early diagnostic blood test is the main objective of this research area to reduce morbidity in implant-associated infections caused by P. acnes.


1.     Gene expression and protein profile during biofilm growth of Propionibacterium acnes

We are interested in the role of protein expression in the biofilm phenotype compared to the planktonic phenotype of P. acnes using liquid-chromatography mass spectrometry (LC-MS). We are mainly interested in the longitudinal gene expression and protein profile during biofilm growth. This will identify potential diagnostic markers and vaccine candidates.

Support by Hartmann-Müller Stiftung, Jubiläumsstiftung Swiss Life.

2.     Propionibacterium acnes: Prevention, diagnosis, and treatment

P. acnes implant-associated infections are difficult to diagnose since the bacterium often needs a prolonged cultivation time of up to 14 days. In collaboration with Prof. Zbinden from the clinical microbiology at the University of Zurich we evaluate optimal cultivation conditions for biopsies from patients with suspected implant-associated infections.

3.     Propionibacterium avidum - a virulent pathogen causing hip periprosthetic Joint infection

Propionibacteria are important members of the human skin microbiota, but are also opportunistic pathogens associated with periprosthetic joint infections (PJI). While the role of Propionibacterium acnes in PJI has been widely described, knowledge regarding the capacity of Propionibacterium avidum to cause PJI is limited. An unusual cluster of four hip PJIs caused by P. avidum in one orthopedic center in 2015 prompted us to identify and analyze clinical data related to P. avidum PJI cases. We also characterize these strains and investigate their phylogenetic relationships by whole genome sequencing.

4.     Bacterial skin colonization with Propionibacterium avidum as a risk factor for
        Periprosthetic joint infections – a single-center prospective study

Since P. avidum mainly cause hip PJI, we investigate skin colonization by P. avidum on different surgical sites.

5.     The role of Propionibacterium acnes infection in intervertebral disc inflammation

Recently, a compelling association between P. acnes and changes in intervertebral discs (IVDs) and adjacent bones (so-called Modic changes) as well as the development of back pain has been described. Since treatment of a subgroup of patients with IVD-related back pain experienced pain reduction upon antibiotic therapy, P. acnes or the subsequent inflammatory responses are described as one of the possible causative factors for low back pain. In other cells, P. acnes has been found to induce inflammatory responses through Toll-like receptor 2 (TLR2)-mediated NF-B activation, but no data currently exists on IVD cells. In this project, we aim to investigate whether and how P. acnes contributes to the inflammatory processes during degenerative disc disease.

Support by CABMM Start up grant with Prof. Karin Würtz)

Research Collaborations

  • Prof. Patrice Francois, PhD, Head of the genomic center, Geneva, Schweiz
  • Prof. Ellie Goldstein, MD, Director, R. M. Alden Research Laboratory, Santa Monica, USA
  • Prof. Andrew McDowell, Assistant Professor in Stratified Medicine NI Centre for Stratified Medicine, Ulster, UK
  • Prof. Mark E. Shirtliff, PhD, Department of Microbial Pathogenesis, Dental School, University of Maryland, Baltimore, USA
  • Prof. Karin Wuertz-Kozak, R.Ph., Ph.D., MBA, Institute for Biomechanics, ETH Zurich
  • Prof. Reinhard Zbinden, MD, Institut für medizinische Mikrobiologie, Zürich, Schweiz
  • Prof. Annelies Zinkernagel, MD Klinik für Infektionskrankheiten und Spitalhygiene, Zürich, Schweiz

PD Dr. med. Yvonne Achermann
Division of Infectious Diseases and Hospital Epidemiology
University Hospital Zurich
Rämistrasse 100
CH-8091 Zürich
Tel +41 44 255 21 73