eCM (Eur Cell Mater / e Cells & Materials) eCM Open Access Scientific Journal
 ISSN:1473-2262         NLM:100973416 (link)         DOI:10.22203/eCM

2013   Volume No 25 – pages 341-350

Title: Intra-cellular Staphylococcus aureus alone causes infection in vivo

Author: T Hamza, M Dietz, D Pham, N Clovis, S Danley, B Li

Address: Nanomedicine Laboratory, Department of Orthopaedics, School of Medicine, West Virginia University, Morgantown, WV 26506-9196, USA

E-mail: bili at hsc.wvu.edu

Key Words: Chronic infection; infection recurrence; intra-cellular pathogen; Staphylococcus aureus; in vivo.

Publication date: July 8th 2013

Abstract: Chronic and recurrent bone infections occur frequently but have not been explained. Staphylococcus aureus (S. aureus) is often found among chronic and recurrent infections and may be responsible for such infections. One possible reason is that S. aureus can internalize and survive within host cells and by doing so, S. aureus can evade both host defense mechanisms and most conventional antibiotic treatments. In this study, we hypothesized that intra-cellular S. aureus could induce infections in vivo. Osteoblasts were infected with S. aureus and, after eliminating extra-cellular S. aureus, inoculated into an open fracture rat model. Bacterial cultures and radiographic observations at post-operative day 21 confirmed local bone infections in animals inoculated with intra-cellular S. aureus within osteoblasts alone. We present direct in vivo evidence that intra-cellular S. aureus could be sufficient to induce bone infection in animals; we found that intra-cellular S. aureus inoculation of as low as 102 colony forming units could induce severe bone infections. Our data may suggest that intra-cellular S. aureus can “hide” in host cells during symptom-free periods and, under certain conditions, they may escape and lead to infection recurrence. Intra-cellular S. aureus therefore could play an important role in the pathogenesis of S. aureus infections, especially those chronic and recurrent infections in which disease episodes may be separated by weeks, months, or even years.

Article download: Pages 341-350 (PDF file)
DOI: 10.22203/eCM.v025a24