Proceeding of Veterinary and Animal Science Days 2016, 8th- 10th June, Milan, Italy 

HAF © 2013 

Vol. III, No. 1s  ISSN: 2283-3927 

   

 

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Keywords 

Methicillin-resistant S. 

epidermidis, nonunion, 

mesenchymal stem cells, rat 

model, osteomyelitis 

 

CORRESPONDING AUTHOR 

Marta Bottagisio 

marta.bottagisio@unimi.it 

 

JOURNAL HOME PAGE 

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Evaluation of antibiotic and cell-based 

therapy in preventing S. epidermidis-induced 

nonunion in rats. 

M. Bottagisio a, b *, L. Drago c, d, C. Romanò e, L. Bonizzi a, A.B. Lovati b 

a Department of Veterinary Science and Public Health, University of Milan, via Celoria 10, 20133 Milan, 
Italy. 

b Cell and Tissue Engineering Laboratory, IRCCS Galeazzi Orthopaedic Institute, via R. Galeazzi 4, 20161 
Milan, Italy. 

c Laboratory of Clinical Chemistry and Microbiology, IRCCS Galeazzi Orthopaedic Institute, via R. 
Galeazzi 4, 20161 Milan, Italy. 

d Department of Biomedical Science for Health, University of Milan, Via L. Mangiagalli 31, 20133 Milan, 
Italy. 

e Dipartimento di Chirurgia Ricostruttiva e delle Infezioni Osteo-articolari, IRCCS Galeazzi Orthopaedic 
Institute, via R. Galeazzi 4, 20161 Milan, Italy. 

 

 
Abstract 

Methicillin-resistant S. epidermidis (MRSE) is responsible for biofilm-related infections (Montanaro, 

2011; Romanò, 2013) and fracture nonunion, as recently demonstrated by our group (Lovati, 2016). 

The present study aims to investigate the efficacy of antibiotic or cell-based therapies in preventing 

bacterial infections and nonunion establishment. 

Under anesthesia, femoral fractures were performed in 30 rats, then the site of injury was injected 

with a clinical-derived MRSE strain and, finally, synthesized with stainless steel plates. Rats were 

differently treated as follows: MRSE-infected controls (IC); systemically-injected vancomycin (s-VANC); 

local vancomycin-enriched hydrogel (l-HYD); systemically-injected BMSCs (s-BMSCs); and locally-

injected BMSCs (l-BMSCs). 

After 6 weeks, pro-inflammatory cytokines, quantitative micro-CT, histological and microbiological 

analyses were carried out to investigate the host response to the different treatments. 

Half of the s-BMSCs rats died closely to the systemic cell injection, thus excluded for further analyses. 

Our results for the IC group were consistent with previously published data (Lovati, 2016), showing 

signs of osteomyelitis and nonunion development. In s-VANC and l-HYD groups, micro-CT detected a 

good bony bridging and the microbiological counts were significantly lower with respect to the other 

groups. Our study suggests that the association of s-VANC and l-HYD is an effective treatment to 

prevent biofilm-induced nonunions. Differently, we cannot positively support cell therapies for this 

purpose due to the high risk related to the systemic cell injection, thus requiring further studies to be 

eventually proposed in clinics.  
 

References 

Lovati, A.B., Romanò, C.L., Bottagisio, M., Monti, L., De Vecchi, E., Previdi, S., Accetta, R., Drago, L., 2016. Modeling Staphylococcus 

epidermidis-Induced Non-Unions: Subclinical and Clinical Evidence in Rats. PLoS One 11, e0147447. 

Montanaro, L., Speziale, P., Campoccia, D., Ravaioli, S., Cangini, I., Pietrocola, G., Giannini, S., Arciola, C.R., 2011. Scenery of Staphylococcus 

implant infections in orthopedics. Future Microbiol 6, 1329-1349. 

Romanò, C.L., Toscano, M., Romanò, D., Drago, L.,2013. Antibiofilm agents and implant-related infections in orthopaedics: where are we? J 

Chemother 25, 67-80. 

 

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