A simple infection model using pre‐colonized implants to reproduce rat chronic Staphylococcus aureus osteomyelitis and study antibiotic treatment

Abstract

E.YOJJO~ S L. CEEI-Arcig6n, Z~i r t r g o~u , SpuiiiAccepted 5 December 2000Institutr oJ Agrohiotcclinolog!., 31006 Pumplonu, Spain AbstractSrq~phploroccus (iureiis biofilms formed on medical implants represent a serious problem, being difficult to eradicate with antibiotic therapy and leading to chronic infections. Simplified in vivo andl in vitro antibiotic susceptibility assays using biofilm bacteria are needed. In this work. a novel chronic osteomyelitis infection model was developed in rats in the absence of bacterial suspension, requiring the use of only lo6 bacteria in biofilms at the site of surgery, with a full success in reproducing infection. Stainless-steel implants pre-colonized for 12 h with a highly adherent S. ciurrus isolate were introduced into the rat tibiae. In animals not submitted to antibiotic treatment, infection was found in the implants and spread to bone in all cases, indicating the high efficacy of the model to reproduce osteomyelitis. The effect of a 21-day treatment with cefuroxime, vancomycin, tobramycin or ciprofloxacin on infection was studied in this model 42 days after surgery. Bone colonization WRS inhibited by vancomycin and cefuroxime. Cefuroxime (the most efficient antibiotic, able to sterilize 1 out of 8 implants) reduced the number of bacteria in biofilms adhered to implants at a higher extent than vancomycin, trobramyciri and ciprofloxacin. Analogous observations were made in this work in vivo and in vitro on the relative antibiotic efficacy against S. CIUWUS biofilm bacteria, suggesting the usefulness of both tests as a potential tool to study antibiotic suceptibility, and the need for new antimicrobials against these bacteria.

Rapid Direct Method for Monitoring Antibiotics in a Mouse Model of Bacterial Biofilm Infection

“…Tobramycin and ciprofloxacin did not reduce the bioluminescence or bacterial counts during treatment and did not cure the infection. This relative resistance of the biofilm to tobramycin and ciprofloxacin is in accordance with previous observations in the literature (15,27,44). Our results are consistent with those of previous studies demonstrating the significant bactericidal effect of rifampin against staphylococcal biofilm infections (1,2,12,13,27,31,37,42,(44)(45)(46)(47).…”

“…It is accepted that eradication of a foreign body-related infection generally requires long courses of combination antibiotic therapy (1,2,12,13,21,23,27,31,32,37,39,47). However, in this study the main intent of the evaluation was the application of an in vivo imaging technology to monitor the effects of different antibiotics on bacterial growth and the recurrence of infection rather than the clinical response per se.…”

Efficacy of Fosfomycin Compared to Vancomycin in Treatment of Implant-Associated Chronic Methicillin-Resistant Staphylococcus aureus Osteomyelitis in Rats

“…twice daily over 21 days (13). Possible explanations for the low efficacy observed for VAN in the treatment of experimental implant-associated osteomyelitis might be poor penetration into osseous tissue and biofilms of this large molecule or the alteration of the antibiotic by biofilm products (24).…”

Molecular and Phenotypic Characteristics of Methicillin-Resistant and Vancomycin-Intermediate Staphylococcus aureus Isolates from Patients with Septic Arthritis

“…Although glycopeptides, including vancomycin and teicoplanin, are commonly used to treat MRSA septic arthritis (44), poor penetration of antibiotics into the periarticular space and biofilm formation on prosthesis make it very difficult to treat septic arthritis caused by S. aureus (17,36).…”