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Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_22 | Pages 8 - 8
1 Dec 2017
Tkhilaishvili T Di Luca M Trampuz A Gaudias J
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Aim

The increase of antimicrobial resistance reduces treatment options for implant-associated infections caused by methicillin-resistant Staphylococcus aureus (MRSA). Bacteriophages present a promising alternative to treat biofilm-related infections due to their rapid bactericidal activity and activity on multi-drug resistant bacteria. In this study, we investigated the synergistic activity of lytic bacteriophage Sb-1 with different antibiotics against MRSA biofilm, using a real-time highly sensitive assay measuring growth-related heat production (microcalorimetry).

Methods

Rifampin, fosfomycin, vancomycin and daptomycin were tested alone and in combination with S. aureus specific phage, Sb-1, against MRSA (Staphylococcus aureus*). MRSA biofilm was formed on porous glass beads (Φ 4 mm, pore size 60 µm) and incubated for 24 h at 37° C in BHI. After 3 times washing biofilms were exposed first to different titers of bacteriophages, ranging from 102 to104 plaque-forming unite (pfu)/ml and after 24h treated again with subinhibitory concentration of antibiotics (corresponding to 1/4, 1/8, 1/16, 1/32 × MHICbiofilm). After 24h antibiotic treatment, the presence of biofilm on glass beads was evaluated by isothermal microcalorimetry for 48h. Heat flow (µW) and total heat (J) were measured.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_22 | Pages 12 - 12
1 Dec 2017
Jenny J Adamczewski B Thomasson ED Gaudias J
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Aim

The diagnosis of peri-prosthetic infection is sometimes difficult to assess, and there is no universal diagnostic test. The recommendations currently accepted include several diagnostic criteria, and are based mainly on the results of deep bacteriological samples, which only provide the diagnosis after surgery. A predictive score of the infection might improve the peri-operative management before repeat surgery after total hip arthroplasty (THA). The goal of this study was to attempt defining a composite score using conventional clinical, radiological and biological data that can be used to predict the positive and negative diagnosis of peri-prosthetic infection before repeat surgery after THA. The tested hypothesis was that the score thus defined allowed an accurate differentiation between infected and non-infected cases in more than 75% of the cases.

Method

104 cases of repeat surgery for any cause after THA were analyzed retrospectively: 61 cases of infection and 43 cases without infection. There were 54 men and 50 women, with a mean age of 70 ± 12 years (range, 30 to 90 years). A univariate analysis looked for individual discriminant factors between infected and uninfected case file records. A multivariate analysis integrated these factors concomitantly. A composite score was defined, and its diagnostic effectiveness was assessed by the percentage of correctly classified cases and by sensitivity and specificity.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 60 - 60
1 May 2016
Jenny J Gaudias J Boeri C Diesinger Y
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INTRODUCTION

Peri-prosthetic fungal infection is generally considered more difficult to cure than a bacterial infection. Two-stage exchange is considered the gold standard of surgical treatment. A recent study, however, reported a favorable outcome after one stage exchange in selected cases where the fungus was identified prior to surgery.

The routine one stage exchange policy for bacterial peri-prosthetic infection involves the risk of identifying a fungal infection mimicking bacterial infection solely on intraoperative samples, i.e. after reimplantation, realizing actually a one stage exchange for fungal infection without pre-operative identification of the responsible fungus, which is considered to have a poor prognosis. We report two such cases of prosthetic hip and knee fungal infection. Despite this negative characteristic, no recurrence of the fungal infection was observed.

CASE N°1: A 78 year old patient was referred for loosening of a chronically infected total hip arthroplasty (Staphylococcus aureus and Streptococcus dysgalactiae). One stage exchange was performed. Intraoperative bacterial cultures remained sterile. Two fungal cultures were positive for Candida albicans. Antifungal treatment was initiated for three months. No infection recurrence was observed at three year follow up.

CASE N° 2: A 53-year-old patient was referred for loosening of a chronically infected total knee prosthesis (Staphylococcus aureus methicillin susceptible, Klebsiella pneumoniae and Staphylococcus epidermidis). One stage exchange was performed. Intraoperative bacterial cultures remained sterile. Five fungal cultures were positive for Candida albicans. Antifungal treatment was initiated for three months. No infection recurrence was observed at two-year follow-up.

DISCUSSION

This experience suggests that eradication of fungal infection of a total hip or knee arthroplasty may be possible after one stage exchange even in cases where the diagnosis of fungal infection was not known before surgery, when the fungus was not identified and its antifungal susceptibility has not been evaluated before surgery. It is however not possible to propose this strategy as a routine procedure.


Orthopaedic Proceedings
Vol. 84-B, Issue SUPP_I | Pages - 55
1 Mar 2002
Brinkert D Gaudias J Boeri C Jenny J
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Purpose: Treatment of infection in patients with an unstable bone is based on removal of implants, bone resection, reconstruction, and external fixation. We report a retrospective series of 11 patients who developed post-traumatic osteitis of the tibia on an unstable bone who were treated by removal of all implants, cleaning, antibiotics, and internal fixation using a centromedullary locked nail.

Material and methods: The series included seven men and four women, mean age 32.4 years (16–56). Initially, there were two closed fractures and nine open fractures (Gustilo II: 4, IIIA: 1; IIIB: 4) treated by external fixation in six cases, centromedullary locked nailing in four and plate fixation in one. Bacteriology results were available for all deep surgical samples. The initial implants were removed in all cases, followed by debridement sparing soft tissue, and reaming of the bone. Adapted antibiotics were prolonged for three months. Refixation using a centromedullary locked nail was performed at the first revision time in two cases and later after cleaning in nine (mean delay 28 days, range 2–53 days). Two cases required a flap for cover.

Results: There were two failures: one due to recurrent infection with a different germ, the other due to necrosis of a latissimus dorsi flap followed by amputation. There were nine successes with bone healing in all cases (first intention in eight and after complementary bone graft in one) and no recurrent infection at the current mean follow-up of 2.6 years.

Discussion: These eleven cases have a common feature of no extensive bone necrosis or major bone defect. Bone resection was basically related to reaming with a minimalistic approach for soft tissue debridement. Reliable bacteriological examinations, effective antibiotic therapy, and prolonged and rapid skin cover are essential elements for success.

Conclusion: This experience is limited but does demonstrate that locked centromedullary nailing can be successful for the treatment of long bone infections on unstable bones, considering that this could be the ideal fixation method.