Method

Two evolved bacteriophages (MRSA-R14 and COL-R23) with improved antibiofilm activity against a clinical isolate (MRSA3) were tested in combination with vancomycin and a carboxymethylcellulose (CMC) hydrogel in vitro and in vivo. MRSA3 bacterial biofilms were formed on sterile 4 mm sintered porous glass beads at 37 °C for 24 h. Biofilms were exposed to i-phage cocktail (10⁷ PFU/ml), ii-vancomycin at concentrations of 0.5, 1, 10 and 100 times the MIC, or iii-combination of phage cocktail and vancomycin. Recovered biofilm cells, were quantified by colony counting. The stability and release profiles of phage cocktail and vancomycin in co-delivery hydrogel were assessed in vitro for 8 days and 72 hrs, respectively, and subsequently tested in the treatment of 5-day-old MRSA3 infection of a femoral plate osteotomy in mice.

Method

Consecutive patients with streptococcal PJI (defined by EBJIS criteria) treated 2009–2021 were prospectively included and allocated into standard and suppression (> 6 months) treatment group. Infection-free survival was assessed with Kaplan-Meier-method and compared between the groups with log rank test. Rates of infection-free, streptococcal infection-free and relapse-free status as well as tolerability of suppression were assessed.

Method

8 patients (2 female and 6 male) with complex orthopedic and cardiovascular infections were included, in whom standard treatment was not feasible or impossible. The treatment was performed in agreement with the Article 37 of the Declaration of Helsinki. Commercial or individually prepared bacteriophages were provided by ELIAVA Institute in Tbilisi, Georgia. Bacteriophages were applied during surgery and continued through drains placed during surgery three times per day for the following 5–14 days. Follow-up ranged from 1 to 28 months.

Method

Consecutive patients with suspicion of septic arthritis were prospectively included. They underwent joint aspiration and synovial fluid was collected for culture, leukocyte count and D-lactate concentration (by spectrophotometry). Youden's J statistic was used for determining optimal D-lactate cut-off value on the receiver operating characteristic (ROC) curve by maximizing sensitivity and specificity.

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.

Method

A descriptive in vitro study was conducted. One 4xHp and one BPTBp were prepared. They were subsequently divided into 8 fragments. Three of them were reserved for negative control, and the rest were contaminated with a strain of S. Epidermidis (ATCC 35984) 10–5. Finally, a quantitative analysis was carried out by means of microcalorimetry and sonication with plating. Additionally, a qualitative analysis was carried out by means of electron microscopy.

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.

Method

Consecutive patients with PJI caused by at least one of the following isolates were prospectively included: staphylococci (MIC ≤32 mg/l), streptococci (MIC ≤128 mg/l), enterococci (MIC ≤128 mg/l), Enterobacteriaceae (MIC ≤32 mg/l) and Pseudomonas spp. (MIC ≤128 mg/l). PJI was defined by the proposed European Bone and Joint Infection Society (EBJIS) criteria. Follow up with clinical (joint function and quality of life scores), laboratory and radiological evaluation at 3, 12 and 24 months after last surgery is performed. Infection outcome was assessed as the proportion of infection-free patients. The probability of infection-free survival was estimated using the Kaplan-Meier survival method.

Method

The stability of Sb-1 in G. mellonella larvae was investigated by injecting a phage titer of 10⁸ PFU and evaluating the presence of Sb-1 in hemolymph at different time points. For infection experiments, sterile stainless-steel K-wires (4 mm, 0.6 mm Ø) were implanted into larvae. Two days after implant, larvae were infected with MRSA ATCC 43300 (1×10⁵ CFU) and incubated at 37°C for further 2 days. Implanted-infected larvae were thus treated for 2 days (3×/day) with 10µL of: i) PBS; ii) Sb-1 (10⁷ PFU); iii) Daptomycin (4mg/kg), iv) PBS (24h)/Daptomycin(24h); v) Sb-1(24h)/Daptomycin(24h). To evaluate the prophylactic efficacy of Sb-1, an experiment based on phages or vancomycin (10mg/kg) administration, followed by MRSA infection of implanted larvae was performed. Both two days post-infection and post-treatment, K-wires were explanted, and the material was sonicated and plated for MRSA colony counting.

Method

Consecutive patients undergoing diagnostic joint aspiration of prosthetic joint were prospectively included. PJI was diagnosed according to the proposed European Bone and Joint Infection Society (EBJIS) definition criteria. Synovial fluid was collected for culture, D-lactate measurement (by spectrophotometry, λ = 570 nm) and leukocyte count and differential (by flow cytometry). The receiver operating characteristic (ROC) analysis was performed to assess the diagnostic performance of D-lactate and leukocyte count.

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).

Method

Culture-positive PJI cases treated at our institution from 02/2011 to 07/2018, for which culture results from preoperative (synovial fluid) and intraoperative samples (periprosthetic tissue, synovial or sonication fluid) were available, were retrospectively assessed. For organisms belonging to the resident skin flora (coagulase-negative staphylococci, cutibacteria and corynebacteria) significant growth was considered, if the identical pathogen grew in ≥2 samples or >50 cfu/ml sonication fluid. For other pathogens (S. aureus, streptococci, enterococci, fungi and gram-negative rods) or patients under antimicrobials, any growth was considered positive. We determined the pathogen detection rate in preoperative and intraoperative cultures and compared it in different subgroups using Fisher's exact test. Furthermore, we assessed the concordance of preoperative and intraoperative cultures.

Method

A 24h-old MRSA ATCC 43300 biofilm was exposed to 1024 µg/ml VAN for 24h. Metabolism-related heat of biofilm-embedded cells, either during or after VAN-treatment, was monitored in real-time by IMC for 24 or 48h, respectively. To evaluate the presence of VAN-derived “persisters” after antibiotic treatment, beads were sonicated and detached free-floating bacteria were further challenged with 100xMIC VAN (100 µg/ml) in PBS+1% Cation Adjusted Mueller Hinton Broth (CAMHB).. Suspensions were plated for colony counting. The resumption of persister cells' normal growth was analysed by IMC on dislodged trated cells for 15h in CAMHB. Activity of 16 µg/ml daptomycin was assessed against persister cells by colony counting.

Patients and Methods

In a retrospective analysis with a standard postoperative follow-up, 95 patients with a PJI of the hip and knee who were treated with a two-stage exchange between 2013 and 2017 formed the study group. A historical cohort of 86 patients treated between 2009 and 2011 not according to the standardized protocol served as a control group. The success of treatment was defined according to the Delphi criteria in a two-year follow-up.

Method

Consecutive patients with IIF diagnosed at our institution from 01/2010-10/2017 were retrospectively included. Infection was defined as visible purulence, sinus tract, microbial growth in ≥2 independent samples or positive histopathology. The outcome was compared before and after implementation of a comprehensive surgical and antimicrobial treatment algorithm in 04/2013.

Method

The susceptibility of 25 MRSA and 18 methicillin-sensitive Sa (MSSA) strains to the ASPL was evaluated by spot assay. In addition, susceptibility of four laboratory MRSA strains, including ATCC 43300, ATCC 33591, Mu3 (MRSA/hetero vancomycin intermediate resistant Sa) and Mu50 (MRSA/vancomycin-resistant Sa) was also tested. The activity of ASPL against planktonic and biofilm-embedded MRSA ATCC 43300 was evaluated in real-time by isothermal microcalorimetry. The minimum heat inhibitory concentrations (MHIC) was defined as the lowest antimicrobial concentration leading to the lack of heat flow production after 24h for both planktonic and biofilm-embedded cells. The viability of bacterial cells was assessed by plating and colony counting. The minimum bactericidal concentration (MBC) was defined as the lowest antimicrobial concentration leading the reduction of 3 log CFU compared to the untreated control.

Method

In vitro a mature biofilms of Staphylococcus epidermidis (ATCC 35984) and P. aeruginosa ATCC®53278) were grown on porous glass beads for 3 days in inoculated brain heart infusion broth (BHI). After biofilm formation, beads were exposed to 0.9% NaCl (control), sonication (40 kHz, 1 min, 0.2 W/cm²), EDTA (25 mM/15 min) and DTT (1 g/L/15 min). Quantitative and qualitative biofilm analysis were performed with viable counts (CFU/ml) and microcalorimetry using time to detection (TTD), defined as the time from insertion of the ampoule into the calorimeter until the exponentially rising of heat flow signal exceeded 100 μW, which is inversely proportional to the amount of remaining bacterial biofilm on the beads. All experiments were performed in triplicate.

Method

MRSA ATCC 43300 24h-old biofilm was treated for 18h with Sb-1 titers (from 10⁴ to 10⁶ pfu/ml). Biofilm matrix was evaluated by confocal laser scanning microscopy after staining with wheat germ agglutinin conjugate with Alexafluor488 (WGA488) to label exopolysaccharide matrix and Syto 85 to label bacterial cells. Persister status was induced using two different protocols: i) by exposing stationary phase S. aureus to 400 µg/ml carbonyl cyanide m-chlorophenylhydrazone (CCCP) in PBS for 3h at 37°C and ii) by treatment of 24h old biofilm with 512 µg/ml ciprofloxacin for further 24h at 37°C. Then, induced persister cells and non-induced controls (10⁶ CFU/ml) were treated with 10⁴ PFU/ml and 10⁷ PFU/ml Sb-1 for 3h, followed by CFU counting. Alternatively, bacteria were washed and incubated in fresh BHI medium for the resumption of normal growth and the bacterial growth assessed after further 24 hours.

Method

Patients treated at our institution with Candida PJI from 01/2017 to 04/2018 were retrospectively included with isolation of Candida spp. in synovial fluid, intraoperative tissue or sonication fluid culture. PJI was defined by the proposed European Bone and Joint Infection Society (EBJIS) criteria. Treatment failure was defined as relapse or persistence of infection.

Method

In this retrospective cohort study, all patients treated with a two stage revision using resection arthroplasty for PHI were included from 2008 to 2014. During the first stage, the prosthesis was removed resulting in a resection arthroplasty without the use a PMMA spacer. During second stage, (cemented or uncemented) reimplantation of the hip prosthesis was performed. The cohort was stratified into two groups according to the length of prosthesis-free interval (≤10 weeks and >10 weeks). Data on complications during explantation, prosthesis-free interval, reimplantation, and after reimplantation was collected. The overall complication rate between both groups was compared using the chi-squared test. The revision-free and infection-free survival was estimated using Kaplan-Meier survival analysis.

Method

Ciprofloxacin was tested alone and in combination with Pyo-bacteriophage cocktail against P.aeurginosa ATCC 27853 and MRSA ATCC 43300 mixed-species biofilm. In order to evaluate the effect of combined treatment on biofilm-embedded cells, mature biofilms were grown on porous glass beads with MRSA (10⁶ CFU/ml) and P.aeruginosa (10³ CFU/ml) and incubated for 24h at 37° C in LB broth. The beads were then washed and placed in fresh LB in the presence of sub-eradicating titers/concentrations of phages and ciprofloxacin (corresponding to 1/4, 1/8, 1/16, 1/32, 1/64, 1/128 × MBEC_biofilm), respectively, simultaneous or in order (pretreated with phages for 3-6-12-24 hours) at 37°C. In all cases, heat flow produced by the viable cells still embedded in the biofilm was measured for 48 hours by isothermal microcalorimetry

Method

Consecutive adult patients with SIAI treated between 2015 and 2017 were prosepctively included. SIAI was defined by: (i) significant microbial growth from intraoperative tissue or sonication fluid, (ii) intraoperative purulence, secondary wound dehiscence or implant on view, (iii) radiographic evidence of infection and fever (>38°C) without other recognized cause, increasing back pain or neurologic impairment, (iv) peri-implant tissue inflammation in histopathology.

Method

We evaluated the radiologic appearance of preoperative standard x-ray images in 421 surgeries performed in 380 patients with internal fixation device in place (56.8% male, mean age 53 ± 17 years). This prospective study was performed in a large single center for musculoskeletal surgery from 2013–2017. Infection was suspected preoperatively in only 23.8% of the surgeries. The most common indications for surgeries in which infection was not suspected were nonunion (84 cases) and symptomatic hardware (57 cases). All removed implants were sent to sonication for biofilm removal and detection. In addition, several peri-implant tissue samples were collected. Radiographs were analyzed in a blinded fashion for signs of radiolucent lines around the implant before removal, hardware fracture or displacement, and soft periosteal reactions suggestive of infection. Diagnosis was established according to the IDSA criteria for PJI. Contingency tables were constructed to determine sensitivity and specificity, and to perform Chi-square tests to compare the presence of infection with radiological signs of infection.

Method

Consecutive patients with enterococcal PJI treated at two specialized orthopaedic institutions were retrospectively included from 2010 to 2017. PJI was defined by the proposed European Bone and Joint Infection Society (EBJIS) criteria. Adequate antimicrobial treatment was considered when the antibiotic was appropiate for the treatment of enterococcal bone infections (activity, dose, oral bioavailability, bone penetration). The treatment success (defined as no relapse of enteroccal infection) and clinical success(i.e. infection-free status) was evaluated and compared using Fishers exact test.

Method

We prospectively included patients with native or prosthetic joints undergoing synovial fluid aspiration as routine diagnostic procedure. Among 224 patients with prosthetic joints, 137 patients had aseptic loosening (AL) and 87 were diagnosed with PJI. Among 71 patients with native joints, 39 were diagnosed with osteoarthrosis (OA) and 32 with SA.

Method

We reviewed the microbiological results following 356 surgeries that included partial or complete removal of internal fixation, performed in 328 patients (54% male, mean age 53 ± 17 years), in which infection was not initially suspected. This prospective study was performed in a large single center for musculoskeletal surgery from 2013–2017. The implants most commonly removed were plate and/or screws (281 cases, 78,9%), followed by intramedullary nails (64 cases, 18,0%). The main indications for surgery were nonunion (89 cases, 25%) and symptomatic hardware (70 cases, 19,7%). All removed implants were sonicated, and tissue cultures were obtained depending on the surgeon's criteria. Diagnosis of infection was established by the presence of 2 or more positive tissue cultures (1 with a highly virulent microorganism), or ≥ 50 colony-forming units found in the sonication fluid.

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.

Methods

Saliva collected from 10 volunteers and 500 ml of sewage water were screened for the presence of lytic phages active against 20 clinical strains of Staphylococcus aureus and 10 of Escherichia coli, both isolated from patients with prosthetic joint infection. Laboratory strains of methicillin-resistant S. aureus (MRSA)*1 and E. coli*2 were also tested. Screening was performed plaque-assay to detect phages for different strains. Isolated plaques were collected and phages were enriched to determine their activity against their bacterial host strains. The activity of bacteriophages against adherent E. coli and MRSA was evaluated by crystal violet, staining bacterial biofilms grown on glass beads.

Aim

To evaluate the performance of measurement synovial fluid (SF) D-lactate (as a pathogen-specific marker) for the diagnosis of PJI and estimate of treatment success.

Method

224 patients undergoing removal knee or hip prosthesis were included in the study between January 2015 and March 2017. 173 patients of this group had aseptic loosening of prosthesis and 87 were diagnosed with PJI. Prior to surgery, synovial fluid routine culture, D-lactate test, leukocyte count and neutrophils (%) were performed for each patient. In order to evaluate a treatment success, the measurement of SF D-lactate before second two-stage exchange procedure (after treatment) was implemented in 30 patients. Diagnosis of PJI was established according to modified Zimmerli criteria.

Method

In this prospective multicenter study we included all consecutive patients with painful prosthetic hip and knee joints undergoing diagnostic joint aspiration. Alpha defensin lateral flow test was used according to manufacturer instructions. The following diagnostic criteria were used to confirm infection: Musculoskeletal Infection Society (MSIS), Infectious Diseases Society of America (IDSA) and Swiss orthopedics and Swiss Society of Infectious Diseases (SOSSID). In the latter, PJI was confirmed when at least one of following criteria applied: macroscopic purulence, sinus tract, positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), histological proof of acute inflammation in periprosthetic tissue, positive culture (from aspirate, tissue or sonication fluid). Infection was classified as chronic, if symptom duration was more than 3 weeks or if infection manifested after more than 1 month after surgery. The sensitivity and specificity of the alpha defensin lateral flow test and leukocyte count in synovial fluid were calculated and compared using McNemar Chi-square test.

Method

We retrospectively analysed all consecutive patients with hPJI, who were treated at our institution from January 2010 until December 2016. Diagnosis of PJI was established if 1 of the following criteria applied:(i) macroscopic purulence, (ii) presence of sinus tract, (iii) positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), (iv) significant microbial growth in synovial fluid, periprosthetic tissue or sonication culture of retrieved prosthesis components, (v) positive histopathology. PJI was classified as hematogenous if the following criteria were fulfilled additionally: (1) onset of symptoms more than 1 month after arthroplasty AND (2) i) isolation of the same organism in blood cultures OR ii) evidence of a distant infectious focus consistent with the pathogen.

Method

In this prospective cohort study, consecutive patients with a painful prosthesis of the lower limb were eligible for inclusion. In addition to standard diagnostics of PJI, alpha-defensin was determined in the aspirated synovial fluid between October 2016 and April 2017. PJI was defined according to the modified Zimmerli criteria, the Musculoskeletal Infection Society (MSIS) criteria and the Infectious Disease Society of America (IDSA) criteria. A positive quantitative alpha-defensin test was defined at a cut-off value of 5.2 mg/L. The sensitivity, specificity, accuracy and area under the curve of each test were determined and the AUCs were compared among each other.

Methods

Patients with hip and knee PJI from 2013 to 2015 were prospectively included and followed-up for ≥2 years. DTT PJI was defined as growth of microorganism(s) resistant to biofilm-active antibiotics. The Kaplan-Meier survival analysis was used to compare the probability of infection-free survival between DTT and non-DTT PJI.

Method

We retrospectively included consecutive patients with OIAI caused by Cutibacterium spp. treated at our institution from January 2012 to January 2017. OIAI was diagnosed when: (i) macroscopic purulence, sinus tract or exposed implant was present; (ii) acute inflammation in peri-implant-tissue was documented; (iii) Cutibacterium spp. grew in joint aspirate, ≥2 intraoperative peri-implant tissue samples or in sonication fluid of the removed implant (>50 CFU/ml).

Method

For the purpose of the study we included patients planed for revision surgery for presumed aseptic failure. Intraoperatively acquired samples of periprosthetic tissue and explanted prosthesis were microbiologicaly evaluated using standard microbiologic methods and sonication. If prosthetic joint infection was discovered, additional therapy was introduced.

Method

In this retrospective study we included all patients with suspected PJI or bone and joint infection without endoprosthesis, hospitalized at our orthopaedic clinic from January 2009 through March 2014. Excluded were patients with superficial surgical site infections or missing data. Demographic, clinical and microbiological data were collected using a standardized case report form. Groups were compared regarding infections caused by oral bacteria. χ2 test or Fisher's exact test was employed for categorical variables and t-test for continuous variables.

Method

We tested six clinically important biomaterials: cobalt chrome alloy, pure titanium, grid-blasted titanium, porous plasma-coated titanium with/without hydroxyapatite, and polyethylene. Two laboratory strains of bacteria commonly causing PJI were used, namely Staphylococcus aureus* and Staphylococcus epidermidis*. After overnight incubation with biofilm formation, the test samples were washed and individually exposed to increasing daptomycin concentrations (4–256 mg/l) during 24-hours. Samples were subsequently sonicated in order to detect dislodged biofilm bacteria on blood agar plates by viable growth and transferred to a microcalorimeter*** for real-time measurement of growth related heat flow during 24-h incubation. Minimal biofilm eradication concentration (MBEC) was determined as the lowest concentration of antibiotic required to eradicate the biofilm bacteria on the sample.

The time to detection expressed as the heat flow >50 µW (TTD-50) indirectly quantifies the initial amount of biofilm bacteria, with a shorter TTD-50 representing a larger amount of bacteria.

Patients and Methods

Streptococcal PJI episodes which occurred between January 2009 and December 2015 were identified from clinical databases. Presentation and clinical outcomes for 30 streptococcal PJIs in 30 patients (12 hip and 18 knee arthroplasties) following treatment were evaluated from the medical notes and at review. The Kaplan-Meier survival method was used to estimate the probability of infection-free survival. The influence of the biofilm active antibiotic rifampin was also assessed.

Method

For the purpose of the study we included patients planed for revision surgery for presumed aseptic failure. Intraoperatively acquired samples of periprosthetic tissue and explanted prosthesis were microbiologically evaluated using standard microbiologic methods and sonication. If prosthetic joint infection was discovered, additional therapy was introduced.

Method

Two S. aureus specific bacteriophages, Sb-1 and Pyo-bacteriophage cocktail, were tested against S. aureus MRSA (ATCC 43300). MRSA biofilm was formed on porous glass beads and incubated for 24 h at 37° C in BHI, washed 3 times and exposed to different concentrations of bacteriophages. For biofilm prevention, MRSA (5×10⁶ CFUs/ml) was incubated with different phage titers. Glass beads were placed in the calorimeter and heat flow (µW) and total heat (J) were measured in real-time for 48h (eradication) or 24h (prevention).

Method

The GLBGS (17,5 mg gentamicin/ml paste) with 40% hydroxyapatite/60% calcium sulfate¹ was tested against biofilms of methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300, methicillin-susceptible S. aureus (MSSA) ATCC 29213, Escherichia coli Bj HDE-1, S. epidermidis ATCC 12228 and Enterococcus faecalis ATCC 19433. For prevention studies, glass beads and different combinations of GLBGS were co-incubated for 24h at 37°C in CAMH broth with 1–5 × 10⁶ CFU/mL of bacteria. For eradication, biofilms were formed on glass beads for 24h at 37°C in CAMH broth. Then, beads were incubated with different combinations of GLBGS in medium at 37°C for 24h. For microcalorimetric measurements, beads were placed in ampoules and heat flow (µW) and total heat (J) were measured at 37°C for 24h. The minimal heat inhibitory concentration (MHIC) was defined as the lowest gentamicin concentration reducing the heat flow peak by ≥90% at 24h.

Methods

Seventy four patients undergoing a two staged revision THA surgery between 2006 and 2013 were included in this retrospective cohort study. Both synovial cultures and CRP values were acquired before explantation of the THA and of the Girdlestone hip before reimplantation. An antibiotic holiday of 14 days was observed prior to synovial aspiration.

A PJI was defined according to the following criteria: intraarticular presence of pus or a sinus tract, a periprosthetic membrane indicative of infection in the histological analysis, or a positive microbiological isolation in a minimum of two samples.

Methods

In this prospective multicentre study (level of evidence: Ia), we included all consecutive adults ≥18 years of age, who underwent explantation of the hip prosthesis for infection or aseptic reason. Excluded were patients in whom part of the prosthetic components were retained. A standardized and comprehensive diagnostic algorithm was applied, including sonication of all removed prosthetic components for qualitative and quantitative microbiological analysis (ultrasound bath 40 kHz, 1 W/cm2, 1 min). Individual components (metal, PE, ceramic) were separately placed in sterile boxes for investigation. All patients were simultaneously included in the European Prosthetic joint infection cohort (EPJIC, www.epjic.org) to ensure long-term follow-up.

Methods

Between 10/2009 and 02/2010 we prospectively included all removed orthopaedic devices at our institution, which were subjected to sonication. Periprosthetic tissue cultures were performed as standard procedure. The removed device was sonicated in Ringer solution (40 kHz, 1 minute) and the resulting fluid was cultured and centrifuged (3000 × g, 10 minutes). The resulting pellet was resuspended in 3 ml tryptic soy broth for isothermal microcalorimetry (sensitivity of 0.25 μW). The detection time until increase of 20 μW was calculated. A 48-channel batch calorimeter (TA Instruments, New Castle, DE, USA) was used to measure the heat flow at 37°C controlled at 0.0001 °C.

Methods

Between 01/2005 and 12/2009 we retrospectively included all type III grade open fractures of the leg at our institution classified after Gustilo (JBJS Am 1976) into type IIIA (adequate soft-tissue coverage of bone with extensive soft-tissue laceration or flaps), IIIB (extensive soft-tissue loss with periosteal stripping and bone exposure), and IIIC (requiring arterial injury repair). Demographic characteristics, clinical presentation, microbiology, surgical and antibiotic treatment and patient outcome were recorded using a standardized case-report form.