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Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_10 | Pages 52 - 52
1 Oct 2022
Müller N Trampuz A Gonzalez-Moreno M
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Aim

The rise of multidrug-resistant bacteria and the decreasing efficacy of antibiotic therapy in successfully treating biofilm-associated infections are prompting the exploration of alternative treatment options. This study investigates the efficacy of different bioactive glass (BAG) formulations - alone or combined with vancomycin - to eradicate biofilm. Further, we study the influence of BAG on pH and osmotic pressure as important factors limiting bacterial growth.

Method

Different BAG-S53P4 formulations were used for this study, including (a) BAG-powder (<45 μm), (b) BAG-granules (500–800 μm), (c) a cone-shaped BAG-scaffold and (d) two kinds of BAG-putty containing granules, with no powder (putty-A) or with additional powder (putty-B), and a synthetic binder. Inert glass beads were included as control. All formulations were tested in a concentration of 1750 g/ml in Müller-Hinton-Broth. Targeted bacteria included methicillin-resistant Staphylococcus aureus (MRSA) and epidermidis (MRSE). Vancomycin was tested at the minimum-inhibitory-concentration for each strain (1 µg/ml for MRSA; 2 μg/ml for MRSE).

To investigate the antibiofilm effect of BAG alone or combined with vancomycin, 3 hour-old MRSA or MRSE biofilms were formed on porous glass beads and exposed to BAG ± vancomycin for 24h, 72h and 168h. After co-incubation, biofilm-beads were deep-washed in phosphate-buffered saline and placed in glass vials containing fresh medium. Recovering biofilm bacteria were detected by measuring growth-related heat production at 37°C for 24h by isothermal microcalorimetry.

Changes in pH and osmotic pressure over time were assessed after co-incubation of each BAG formulation in Müller-Hinton-Broth for 0h, 24h, 72h and 168h.


Orthopaedic Proceedings
Vol. 103-B, Issue SUPP_5 | Pages 7 - 7
1 Mar 2021
Wang L Tkhilaishvili T Trampuz A Gonzalez-Moreno M
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Aim

Rifampicin plays an important role in the treatment of staphylococcal prosthetic joint infection, as rifampicin-containing combinations have shown a high efficacy against S. aureus biofilm infections. However, the emergence of rifampin-resistant strains is a feared complication and the use of rifampicin in those cases seems unwarranted. Therefore, we evaluated the activity of bacteriophage Sb1 in combination with different antibiotics against the biofilm of four rifampicin-resistant MRSA strains as alternative therapeutic approach.

Method

Four rifampicin-resistant MRSA strains were used in this study. The MIC for all tested antibiotics was determined by Etest. Biofilms were formed on porous glass beads for 24h and exposed to Sb1 (107 PFU/mL) for 24h followed by exposure to antibiotic for 24h. Viability of bacteria after antimicrobial treatment was detected by beads sonication and plating of the sonication fluids. The minimum biofilm eradication concentration (MBEC) was defined as the lowest concentration of antibiotic required to kill all cells resulting in the appearance of no colony after plating of the sonication fluid (detection limit <20 CFU/mL). The synergistic effects were observed when Sb1 combined with antibiotics used at least 2 log-reduction lower concentrations.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_14 | Pages 17 - 17
1 Dec 2019
Wang L Luca MD Tkhilaishvili T Gonzalez-Moreno M Trampuz A
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Aim

Ciprofloxacin is recommended as anti-biofilm therapy for gram-negative periprosthetic joint infection. With ciprofloxacin monotherapy, resistance in gram-negative bacteria was observed. Therefore, we evaluated in vitro synergistic activity of fosfomycin, ciprofloxacin and gentamicin combinations against biofilms formed by E. coli and P. aeruginosa strains.

Method

E. coli ATCC 25922, P. aeruginosa ATCC 27853 and 15 clinical isolates were used for this study. MIC values were determined by Etest. Biofilms were formed on porous sintered glass beads for 24h and exposed to antibiotics for further 24h. Viability of bacteria on the glass beads after antibiotic treatment was detected by cfu counting of the sonicated beads. The minimum biofilm eradication concentration (MBEC) was defined as the lowest concentration of antibiotic required to kill biofilm cells. Synergistic activity against biofilm was evaluated by calculation of the fractional inhibitory concentration index (FICI).


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 424 - 424
1 Dec 2013
Meller M Gonzalez M Greenwald AS
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The prevalence of Class III Obesity (BMI ≥ 40 kg/m25) in black women is 18%, three times the 6 national average. Class III obesity is associated with mobility limitations, particularly hip joint 7 deterioration. Therefore black women are highly likely to come to the attention of orthopedic 8 surgeons. Weight loss associated with bariatric surgery should lead to enhanced success of hip 9 replacements. However, we present a case of a black woman who underwent Roux-en-y gastric 10 bypass with the expectation that weight loss would improve her ambulation and if necessary 11 make her a better surgical candidate for hip replacement. Her gastric bypass was successful as her BMI declined from 52.0 kg/m2 to 33.7 kg/m212. However, her hip circumference post weight 13 loss remained persistently high. As a consequence, the soft tissue tunnel geometry presented 14 major challenges. The tunnel depth as well as the immobility of the soft tissue envelope 15 interfered with retractor placement, tissue reflection and adequate surgical access to the 16 acetabulum. Therefore a traditional cup placement could not be achieved. Instead, a 17 hemiarthroplasty was performed. Her pre-surgery Harris Hip Score was 17.0. In the first few 18 months post surgery there were improvements, specifically a decrease in pain and a decreased 19 reliance on external support. But her overall functional independence never improved. This case 20 is presented to raise awareness that improved BMI category post bariatric surgery is not 21 sufficient to guarantee that orthopedic risks have been minimized. Overall, weight loss does 22 improve both the metabolic profile and anesthesia risk, but the success rate of total hip 23 arthroplasties will be low if fat mass (i.e. high hip circumference) in the operative field remains 24 high. We are now repeatedly recognizing this problem but are not finding any case reports on 25 this issue. Therefore we provide a practical approach to evaluate these patients and describe 26 ways we have found to successfully address intra-operative challenges.