Treatment Of Prosthetic Joint Infections Research Articles

ROUTINE SURGICAL ANTISEPTIC AGENTS ARE INEFFECTIVE IN THE ERADICATION OF TYPICAL PJI BIOFILM FORMED ON ORTHOPAEDIC IMPLANT MATERIAL IN VITRO AND THE ABSENCE OF AN ANTISEPTIC NEUTRALIZATION STAGE GIVES THE FALSE IMPRESSION OF EFFICACY

Prosthetic joint infection (PJI) is a serious complication following joint replacement. Antiseptic solutions are often used for intraoperative wound irrigation particularly in cases of revision for PJI. Antiseptic irrigation is intended to eradicate residual bacteria which may be either free floating or in residual biofilm although there is no clear clinical efficacy for its use. Also, reviewing the scientific literature there is discordance in in vitro results where some studies questions antiseptic efficacy whilst others suggest that even at low concentration antiseptic agents are effective at eradicating bacterial biofilms.The aim of this in vitro study was to establish the efficacy of undiluted antiseptic agents at eradication of a typical PJI forming biofilm and determine the importance of an antiseptic neutralisation step in this assessment.Mature Staphylococcus epidermidis biofilms grown on TiAl6V4 discs were submerged in chlorohexidine (CHL) gluconate 4%, povidone-iodine (PI) 10% or phosphate-buffered saline (PBS) control solution. The discs were then rinsed, the biofilm bacteria suspended in solution using sonication and vortexing, and the viable count (CFU/ml) of the bacterial suspensions determined. The rinse/suspension solution was either (a) PBS or (b) Dey-Engley neutralization broth (NB).When PBS was used to rinse/suspend the biofilm a highly significant, 7.5 and 4.1, mean log reduction in biofilm vitality was observed from the control, for CHL 4% and PI 10%, respectively. However, when NB was the rinse/suspension solution the apparent antiseptic biofilm eradication efficacy was replaced with a statistically significant but clinically irrelevant less the one log-reduction in biofilm vitality.Clinical antiseptic agents are ineffective at eradicating S. epidermidis biofilm in an in vitro PJI model and absence of a neutralisation step gives the false impression of efficacy. Antiseptics alone are an ineffective treatment for biofilm related PJI and no substitute for meticulous debridement.

ANTIMICROBIAL ACTIVITY OF ION-SUBSTITUTED CALCIUM PHOSPHATES: A SYSTEMATIC REVIEW

Prosthetic Joint Infection (PJI) is a devastating complication that can occur after total joint replacement surgery. With increasing antimicrobial resistance, there is a need for non-antibiotic approaches to treat and prevent PJI. Doping calcium phosphates with antimicrobial ions shows promise for these purposes. This systematic review aims to search and summarise the evidence-base for the potential of calcium phosphates doped with different antimicrobial ions.A systematic review was conducted on PubMed, Embase, Web-Of-Science, Cochrane Library and Emcare of in vitro and animal studies on the antimicrobial activity of (co)substituted calcium phosphates according to PRIMSA guidelines.. The research protocol, listing search terms and in/exclusion criteria, was registered a priori at https://doi.org/10.7910/DVN/HEP18U. Data was extracted regarding ions, micro-organisms and antimicrobial activity.The search retrieved 1017 hits of which 148 papers were included. The substitution of 33 different ions was reported. Silver (n= 46), zinc (n=39), copper (n=18) and magnesium (n=14) were the most commonly doped ions. 36 different micro-organisms were studied of which E. coli (n=109), S. aureus (n=99), and C. albicans (n=22) were the most common. 6 different outcomes were reported, most commonly the K-ratio (n=53), the log CFU (n=41) and the bacterial inhibition zone (n=39). A validated outcome for the evaluation of biofilm prevention was lacking.There was considerable heterogeneity in studied ions, micro-organisms and reported outcomes. A lack of clearly defined reporting guidelines in the field of antimicrobial materials has led to the use of clinically irrelevant micro-organisms and a general lack of consistency of the methods used and the reported results. Currently, there is no universally accepted measure for the effectiveness required from biomaterials for treatment and prevention of PJI.

Dare to DAIR: Is Rifampin Always Necessary?

The treatment of early post-operative staphylococcal prosthetic joint infection (PJI) with debridement, antibiotics, and retention of the implant (DAIR) is becoming increasingly common. This approach has many advantages, primarily more rapid mobilization and return to normal activities compared to a one- or two-stage revision [1]. A recent prospective multicenter observational study conducted at 27 hospitals in Australia and New Zealand found that DAIR was as successful as one or two-stage revisions, especially in patients with acute infections [2]. However, there is still considerable confusion as to the best antibiotics and duration of therapy. Some guidelines have adopted rifampin combination therapy as the cornerstone antibiotic treatment for staphylococcal PJI treated with DAIR, based on experimental animal models, one randomized trial, and several cohort studies [3,4]. However, rifampin combination therapy is associated with significant side effects and drug–drug interactions. A common justification for adding rifampin is a prospective randomized trial of early MSSA PJI conducted by Zimmerli and published in 1998 [5]. This was a prospective, randomized, double-blind trial that showed 100% success with combination therapy compared to 58% in the non-rifampin arm. Only 33 patients were included in this trial and only 24 completed the study. Of the 18 patients in the rifampin arm, there were 5 hip replacements, 3 knee replacements and 10 internal fixation devices. In the placebo arm, there were 3 hip replacements, 4 knee replacements and 8 internal fixation devices. This study was certainly a remarkable accomplishment; however, arguably, it should not be considered the definitive word on how to treat PJI with DAIR and drive clinical practice for decades. Unfortunately, it seems that this has been the case given the recommendations of current guidelines.

Combination d-Amino Acid and Photothermal Hydrogel for the Treatment of Prosthetic Joint Infections.

Prosthetic joint infection (PJI) is a devastating complication requiring surgical intervention and prolonged antimicrobial treatment. The prevalence of PJI is on the rise, with an average incidence of 60,000 cases per year and a projected annual cost of $1.85 billion in the US. The underlying pathogenesis of PJI involves the formation of bacterial biofilms that protect the pathogen from the host immune response and antibiotics, making it difficult to eradicate such infections. Biofilms on implants are also resistant to mechanical brushing/scrubbing methods of removal. Since the removal of biofilms is currently only achievable by the replacement of the prosthesis, therapies aimed at eradicating biofilms while enabling retention of implants will revolutionize the management of PJIs. To address severe complications associated with biofilm-related infections on implants, we have developed a combination treatment that is based on a hydrogel nanocomposite system, containing d-amino acids (d-AAs) and gold nanorods, which can be delivered and transforms from a solution to a gel state at physiological temperature for sustained release of d-AAs and light-activated thermal treatment of infected sites. Using this two-step approach to utilize a near-infrared light-activated hydrogel nanocomposite system for thermal treatment, following initial disruption with d-AAs, we were able to successfully demonstrate in vitro the total eradication of mature Staphylococcus aureus biofilms grown on three-dimensional printed Ti-6Al-4V alloy implants. Using a combination of cell assays, computer-aided scanning electron microscopy analyses, and confocal microscopy imaging of the biofilm matrix, we could show 100% eradication of the biofilms using our combination treatment. In contrast, we were only able to see 25% eradication of the biofilms using the debridement, antibiotics, and implant retention method. Moreover, our hydrogel nanocomposite-based treatment approach is adaptable in the clinical setting and capable of combating chronic infections brought about by biofilms on medical implants.

Antimicrobials in polymethylmethacrylate: from prevention to prosthetic joint infection treatment: basic principles and risk of resistance

BackgroundExcellent revisions about antibiotic-loaded bone cement (ALBC) have been recently published. In the present article, we review the principles and limitations of local antibiotic delivery in the context of recent advances in the pathogenesis of prosthetic joint infections (PJI), with particular attention paid to the potential association between ALBC and antimicrobial resistance.Main bodyRecalcitrance of PJI is related to the ability of pathogens to adapt to particular environments present in bone tissue and protect themselves from host immunity in different ways. Accordingly, delivery of high local antimicrobial concentrations using ALBC is needed. Most relevant clinical data showing the efficacy of ALBC for PJI prophylaxis and treatment are reviewed, and we dissected the limitations on the basis of the recent findings from animal models and suggested that aminoglycosides, in particular, could not be the best option. One of the major concerns associated with ALBC is the emergence of resistance because of theoretical prolonged exposure to low antibiotic concentrations. We summarize the mechanisms for the selection of resistant microorganisms, and we critically reviewed the evidence from animal models and clinical data from observational and registry studies and concluded that there is no evidence to support this association.ConclusionWhile waiting for better evidence from well-designed clinical trials, ALBC shows a beneficial effect as a prophylaxis in arthroplasty, and to avoid the colonization of spacers used for two-stage revision in patients with PJI. Experimental models and clinical evidence suggest the need to achieve high local antimicrobial concentrations to obtain the highest prophylactic and therapeutic effect. The current evidence does not support the risk of increasing resistance with use of ALBC. In the future, it is necessary to evaluate new carriers and different antimicrobials to improve clinical outcomes.

One-stage revision using intra-articular vancomycin infusion effectively treats chronic prosthetic joint infection caused by Enterococcal

Objective: To investigate the clinical effects of one-stage revision combined with intra-articular infusion of vancomycin in the treatment of chronic prosthetic joint infection (PJI) caused by Enterococcal. Methods: From May 2013 to June 2020,the clinical data of 9 patients (2 males and 7 females) with chronic Enterococcal PJI treated with one-stage revision using intra-articular infusion of vancomycin at Department of Orthopaedics,First Affiliated Hospital of Xinjiang Medical University were retrospectively analyzed,including 8 hips and 1 knee.A total of 9 patients with age of (63.9±11.7)years (range:43 to 76 years) were included, and the body mass index was (23.6±4.3)kg/m2 (range:18 to 30 kg/m2).There were 6 cases with antibiotic history and 5 cases with sinus tract.The joint fluid,infected tissue around the prosthesis and ultrasonic shock fluid of the prosthesis were collected during operation for microbial culture identification and drug sensitivity test.After thorough debridement of the infected site and removal of the infected prosthesis,a new prosthesis was implanted,then the drainage tube in the operation area was placed.After surgery,vancomycin(1.0 g,q12 h) was combined with intra-articular vancomycin(0.5 g,qd) in monomicrobial PJI,and vancomycin(1.0 g,q12 h) was combined with intra-articular vancomycin (0.5 g,qd) and imipenem/meropenem (0.5 g,qd),and the interval between the two drugs was 12 hours in polymicrobial PJI.Hip and knee functions were evaluated by Harris Hip Score or Knee Society Score(KSS),respectively.The comparison of hip function scores before and after operation was performed by paired t-test. Results: All patients were followed up for (60±39)months(range:24 to 110 months).Two cases were infected with Enterococcus faecium and 7 cases were infected with Enterococcus faecalis.There were 7 cases of monomicrobial infection and 2 cases of polymicrobial infection.Erythromycin(5/9),tetracycline(4/9),ciprofloxacin and β-lactam antibiotics(3/9) were the top three antibiotics in Enterococci resistance rate.The sensitive antibiotics for Enterococcal were vancomycin,linezolid and tigecycline.The average duration of intravenous antibiotics was (14±1)days (range:13 to 17 days),and the average duration of antibiotics in articular cavity was (15±2)days(range:11 to 20 days).Mean duration of oral antibiotic use after discharge was (2±1)months(range:1 to 3 months).One case of polymicrobial PJI treatment failed,with a failure rate of 1/9.At last follow-up,the Harris score of patients with hip PJI increased from (43±6)points to (84±6)points(t=-11.899, P<0.01). KSS score of knee function was improved from 33 point pre-operatively to 85 point post-operatively;overall function score was improved from 35 point pre-operatively to 80 point post-operatively.During the treatment,no formation of sinus tract of the hip joint caused by a catheter,skin necrosis at the knee puncture site or leakage of joint fluid;no complications such as deep vein thrombosis and pulmonary embolism occurred. Conclusions: One-stage revision combined with intra-articular infusion of vancomycin can achieve acceptable infection control rate and joint function in patients with chronic Enterococcus PJI.However,the treatment of polymicrobial PJI still needs to be further verified.

THE PROFILE OF CAUSAL PATHOGEN OF HIP/ KNEE PROSTHETIC JOINT INFECTION (PJI): A SINGLE CENTER STUDY

Introduction: One of the most challenging and serious complications associated with total joint arthroplasty is prosthetic joint infection (PJI). Advancements in prevention, diagnosis, and treatment of PJI seem promising. Accurate identification of the causal pathogen is a key factor for successful treatment and also for choosing antibiotic treatment. This study was aimed to evaluate the prevalence of PJI and distribution of causative pathogen using microbiological culture and pathological examination. Methods: A retrospective descriptive study was conducted by collecting data from our center registry from 2018 to 2020. The inclusion criteria of this study were patients diagnosed with hip or knee PJI based on the diagnostic criteria for PJI. The exclusion criteria were incomplete microbiology data which were either refusal to participate or loss of contact. The data extracted from medical records are demographic data such as age, sex, and microbiology and pathological examination data. Results: A total of 1359 total hip/ knee arthroplasty surgeries were performed during the years 2018–2020. Among them, 1031 were total knee arthroplasty (TKA) and 321 were total hip arthroplasties (THA). During the same period, a total of 52 patients with PJI were treated at our center. There were 31 knee PJI cases (59.61%) and 21 were hip PJI cases (40.38%). Microbiology culture and pathologic anatomy results showed gram positive Staphylococcus sp bacteria, which was the common causal pathogen of PJI. Negative culture results were found in 10/52 (19.23%) of cases. Conclusions: Staphylococcus sp was the most common causal pathogen of Hip/ Knee PJI in our center. Relatively high rate of culture-negative PJI was observed in this study, further strategies are needed to increase the rate of causal pathogen isolation in hip/ knee PJI cases in our center.

Risk of Treatment Failure for Prosthetic Joint Infections: Retrospective Chart Review in an Outpatient Parenteral Antimicrobial Therapy Program.

Prosthetic joint infections (PJIs) are a major complication of total joint replacement surgeries. Treatment includes surgical intervention with prolonged courses of IV antibiotics in outpatient parenteral antimicrobial therapy (OPAT) programs. The risk of PJI treatment failure is high and may be associated with various clinical factors. To determine the rate of PJI treatment failure and to identify potential risk factors for failure in patients admitted to an OPAT program. A retrospective chart review was conducted for adult patients with PJI admitted to an OPAT program between July 1, 2013, and July 1, 2019. Treatment courses were deemed to have failed according to predetermined criteria. χ2 tests and multiple linear regression were used to examine associations of comorbidities, pathogens, and antimicrobial regimens with treatment failure. In total, 100 patients associated with 137 PJI treatment courses in the OPAT program were included. Of these, 28 patients accounted for 65 of the treatment courses. Methicillin-susceptible Staphylococcus aureus was the most frequently isolated pathogen (31/137 or 22.6% of treatment courses). Patient comorbidities included body mass index of at least 30 kg/m2 (58% of patients) and diabetes (41% of patients). The overall rate of treatment failure was 56.2% (77/137 treatment courses). Selected risk factors associated with treatment failure or success were diabetes (50.9% versus 29.8%; odds ratio [OR] 4.03, 95% confidence interval [CI] 1.38-12.88, p = 0.013) and depression (32.1% versus 14.9%; OR 5.02, 95% CI 1.30-22.89, p = 0.025). The overall rate of PJI treatment failure in the study population was high. Patients with diabetes and depression experienced higher incidences of failure. Future investigations of comprehensive PJI management should be considered to ensure successful treatment and to minimize excessive use of health care resources.

Physical Approaches to Prevent and Treat Bacterial Biofilm.

Prosthetic joint infection (PJI) presents several clinical challenges. This is in large part due to the formation of biofilm which can make infection eradication exceedingly difficult. Following an extensive literature search, this review surveys a variety of non-pharmacological methods of preventing and/or treating biofilm within the body and how they could be utilized in the treatment of PJI. Special attention has been paid to physical strategies such as heat, light, sound, and electromagnetic energy, and their uses in biofilm treatment. Though these methods are still under study, they offer a potential means to reduce the morbidity and financial burden related to multiple stage revisions and prolonged systemic antibiotic courses that make up the current gold standard in PJI treatment. Given that these options are still in the early stages of development and offer their own strengths and weaknesses, this review offers an assessment of each method, the progress made on each, and allows for comparison of methods with discussion of future challenges to their implementation in a clinical setting.

986. Pseudomonas Prosthetic Joint Infections: Is there a role for monotherapy?

Abstract Background Pseudomonas species are a less common but devastating pathogen family in prosthetic joint infections (PJI). Despite advancements in management, Pseudomonas PJI remains particularly difficult to treat due to fewer antibiotic options and robust biofilm formation. The purpose of this study was to better evaluate outcomes after Pseudomonas PJI treatment. Methods All hip or knee PJIs, at a single institution, with positive Pseudomonas culture were analyzed. 51 patients (29 hips and 22 knees) meeting inclusion criteria were identified. The primary outcome of interest was infection clearance at 1-year after surgical treatment, defined as reassuring aspirate without ongoing antibiotic treatment or death within one year post-operatively. Monomicrobial and polymicrobial infections were evaluated separately. Results Among monomicrobial PJIs, ten (50.0%) patients were clear of infection at one year post-operatively. Patients treated with 2-stage exchange (n=11) had a 1-year clearance rate of 54.5% compared to 60.0% with DAIR (n=5) and 25.0% with resection or amputation (n=4). Two of six patients treated with fluoroquinolone monotherapy met 1-year infection clearance, despite fluoroquinolone sensitivity, compared to four of five patients meeting 1-year clearance when treated with combined intravenous and oral therapy for at least 6 weeks. Resistance to anti-pseudomonal agents was infrequent (20%, n=4/20), and three of ten mono- and polymicrobial PJI patients with recurrent Pseudomonas PJI developed resistance to anti-pseudomonal therapy. Polymicrobial infections were the most common presentation (54.9%) of Pseudomonas positive PJI with a mortality rate of 46.4% (n=13/28) at a median follow-up of 4.2 years [IQR: 3.4-5.7]. Conclusion Despite surgical and antibiotic treatment regimens consistent with traditional treatment algorithms, our data portrays poor clearance rate of Pseudomonas PJI with relatively poor outcomes in patients treated with oral or intravenous monotherapy. Pseudomonas infections are difficult to eradicate and likely require deviations from classical therapeutic protocols to improve treatment success. Disclosures William A. Jiranek, MD, Biomech Holdings LLC: Stocks/Bonds|DePuy, A Johnson &amp; Johnson Company: IP royalties Thorsten M. Seyler, MD, PhD, Heraeus: Paid consultant|Pattern Health: IP royalties|Restor3d: IP royalties|Smith &amp; Nephew: Paid consultant|Total Joint Orthopedics: Paid consultant|Zimmer: research.

Direct Costs Vary by Outcome in Two-Stage Revision Arthroplasty for the Treatment of Hip Periprosthetic Joint Infection

BackgroundTwo-stage revision arthroplasty is the gold standard for treating chronic prosthetic joint infection (PJI), but there has been limited analysis of the costs incurred beyond the index procedure and how additional complications and/or surgeries impact the cost of care. MethodsThe electronic health record was queried for patients who underwent a total hip arthroplasty complicated by PJI and then underwent removal of the prosthesis with implantation of an antibiotic-impregnated articulating cement spacer. Patient demographics, surgical variables, hospital readmissions, emergency department (ED) visits, and postoperative complications were recorded. Data on total costs were collected with an internal accounting database. The average follow-up duration was 3.35 years. ResultsUnivariate analyses showed statistically significant differences between outcome groups (reimplantation, reimplantation requiring later revision, retained spacer, and Girdlestone resection arthroplasty) in total overall costs, ED visit costs, and postoperative costs at 1 and 2 years after the initial spacer placement. The median total cost at 2 years for each group was $38,865 ($29,144-49,471) (reimplantation), $79,223 ($53,442-100,152) (reimplantation with revision), $54,096 ($20,872-73,903) (retained spacer), $62,134 ($52,135-101,546) (Girdlestone). Patients who underwent successful reimplantation requiring no further surgery had significantly lower total costs than patients who needed revision surgeries after reimplantation ($38,865 [$29,144-49,471] vs $79,223 [$53,442-100,152], P = .007). Patients with a Girdlestone resection arthroplasty had higher total costs at 1 year ($59,708 [$41,781-80,916] vs $33,093 [$27,237-40,429], P = .043) and higher costs attributable to ED visits at 2 years than the reimplantation group ($23,581 [$14,029-41,519] vs $15,307 [$6291-29,119], P = .009). ConclusionsA significant variation exists among total costs for the 2-stage treatment of hip PJI when stratified by the final outcome.

Strain-to-strain variability among Staphylococcus aureus causing prosthetic joint infection drives heterogeneity in response to levofloxacin and rifampicin.

Levofloxacin and rifampicin are the preferred treatment for prosthetic joint infection (PJI) caused by Staphylococcus aureus, especially when managed with implant retention (DAIR). However, a significant variability of success has been reported, which could be related to intrinsic characteristics of the microorganism. Our aim was to evaluate the variability in the anti-biofilm response to levofloxacin and rifampicin in a clinical collection of S. aureus. Eleven levofloxacin- and rifampicin-susceptible S. aureus isolates causing PJI managed with DAIR were included. Levofloxacin, rifampicin and levofloxacin + rifampicin were tested in an in vitro static biofilm model in microtitre plates, where 48 h biofilms were challenged with antimicrobials during 24 h. Additionally, two genetically similar strains were tested in the CDC Biofilm Reactor, where 48 h biofilms were treated during 56 h. Antimicrobial activity was assessed by viable biofilm-embedded cells recount, and by crystal violet staining. All antimicrobial regimens showed significant anti-biofilm activity, but a notable scattering in the response was observed across all strains (inter-strain coefficient of variation for levofloxacin, rifampicin and levofloxacin + rifampicin of 22.8%, 35.8% and 34.5%, respectively). This variability was tempered with the combination regimen when tested in the biofilm reactor. No correlation was observed between the minimal biofilm eradicative concentration and the antimicrobial activity. Recurrent S. aureus isolates exhibited higher biofilm-forming ability compared with strains from resolved infections (7.6 log10 cfu/cm2±0.50 versus 9.0 log10 cfu±0.07). Significant variability may be expected in response to levofloxacin and rifampicin among biofilm-embedded S. aureus. A response in the lower range, together with other factors of bad prognosis, could be responsible of treatment failure.

Intravenous antibiotic duration in the treatment of prosthetic joint infection: systematic review and meta-analysis.

Introduction: Long antibiotic courses, including intravenous (IV) and oral administrations, are utilized in prosthetic joint infection (PJI) treatment. This meta-analysis examines the non-inferiority of short courses ( 4 weeks) of IV antibiotics compared to long courses in treating PJI. Critical review of IV treatment is necessary due to the clinical, physical, and financial burden associated with it and its continued prolonged use in the US without much evidence to support the practice. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), databases were searched using predefined medical subject headings (MeSH). Results: The nine included studies reported 521 total hip arthroplasties (THAs) and 530 total knee arthroplasties (TKAs). There was no significant difference in the overall success rate in short- vs. long-duration IV antibiotics for PJI treatment: odds ratio (OR) of 1.65, 95 % confidence interval (CI) of 0.78-3.46, and .18. However, due to the moderate to high heterogeneity ( %, 0.01) amongst studies, an adjusted success rate was calculated after the exclusion of two studies. This showed a statistically significant difference between both groups (OR of 2.45, 95 % CI of 1.21-4.96, 0.001) favoring a short course of antibiotics and reflecting a more homogenous population ( %, .06). Conclusion: This study highlights the limited data available for evaluating IV antibiotic duration in the setting of PJI. We found that a shorter duration of IV antibiotics was non-inferior to a longer duration, with an improved OR of 2.45 for treatment success, likely shortening inpatient stay as well as lessening side effects and antimicrobial resistance with a lower cost to patients and overall healthcare.

Microbiological Characterization of Cutibacterium acnes Strains Isolated from Prosthetic Joint Infections.

Aims: This study aimed to characterize 79 Cutibacterium acnes strains isolated from prosthetic joint infections (PJIs) originated from eight European hospitals. Methods: Isolates were phylotyped according to the single-locus sequence typing (SLST) scheme. We evaluated the ability of the biofilm formation of C. acnes strains isolated from PJIs and 84 isolates recovered from healthy skin. Antibiotic susceptibility testing of planktonic and biofilm cells of PJI isolates and skin isolates was performed. Results: Most of the isolates from PJIs belonged to the SLST class H/phylotype IB (34.2%), followed by class D/phylotype IA1 (21.5%), class A/phylotype IA1 (18.9%), and class K/phylotype II (13.9%). All tested isolates were biofilm producers; no difference in biofilm formation was observed between the healthy skin group and the PJI group of strains. Planktonic and sessile cells of C. acnes remained highly susceptible to a broad spectrum of antibiotics, including beta-lactams, clindamycin, fluoroquinolones, linezolid, rifampin, and vancomycin. The minimal inhibitory concentrations (MICs) for planktonic and biofilm states coincided in most cases. However, the minimal biofilm eradication concentration (MBEC) was high for all antimicrobial drugs tested (>32 mg/L), except for rifampin (2 mg/L). Conclusions: C. acnes strains isolated from healthy skin were able to produce biofilm to the same extent as isolates recovered from PJIs. All C. acnes strains in planktonic and sessile states were susceptible to most antibiotics commonly used for PJI treatment, although rifampin was the only antimicrobial agent able to eradicate C. acnes embedded in biofilm.

Transfusion Rates in the Operative Treatment of Prosthetic Hip and Knee Infection.

Surgery for prosthetic joint infection (PJI) can often lead to significant blood loss, necessitating allogeneic blood transfusion (ABT). The use of ABT is associated with higher rates of morbidity and death in revision total joint arthroplasty, particularly in the treatment of PJI. We compared ABT rates by procedure type among patients treated for PJI. We retrospectively reviewed 143 operative cases of hip and knee PJI performed at our institution between 2016 and 2018. Procedures were categorized as irrigation and debridement (I&D) with modular component exchange (modular component exchange), explantation with I&D and placement of an antibiotic spacer (explantation), I&D with antibiotic spacer exchange (spacer exchange), or antibiotic spacer removal and prosthetic reimplantation (reimplantation). Rates of ABT and the number of units transfused were assessed. Factors associated with ABT were assessed with a multilevel mixed-effects regression model. Of the cases, 77 (54%) required ABT. The highest rates of ABT occurred during explantation (74%) and spacer exchange (72%), followed by reimplantation (36%) and modular component exchange (33%). A lower preoperative hemoglobin level was associated with higher odds of ABT. Explantation, reimplantation, and spacer exchange were associated with greater odds of ABT. Antibiotic spacer exchange and explantation were associated with greater odds of multiple-unit transfusion. Rates of ABT remain high in the surgical treatment of PJI. Antibiotic spacer exchange and explantation procedures had high rates of multiple-unit transfusions, and additional units of blood should be made available. Preoperative anemia should be treated when possible, and further refinement of blood management protocols for prosthetic joint infection is necessary. [Orthopedics. 2022;45(6):353-359.].

159 Current Practice of Intra-Operative Sampling During Revision Surgery of the Knee for Prosthetic Joint Infection at a High-Volume District General Hospital

Abstract Aim Successful treatment of prosthetic joint infection (PJI) involves surgical interventions and identification of infecting organisms to enable targeted antimicrobial therapy. Current PHE guidelines recommend 3–5 intra-operative samples to be taken using separate instruments for each, swabs are discouraged. We audited the revision arthroplasty practice at Barking, Havering, Redbridge University Trust (BHRUT), specifically comparing intra-operative sampling for infected revision knee procedures with these guidelines. Method Retrospective cohort study of all prosthetic knee infection cases, as defined by the Musculoskeletal Infection Society criteria, at BHRUT between December 2011 to May 2020. A review of case notes collected various key data points, focusing on intraoperative sample, type, number, and technique. Point biserial correlation analysis was performed to determine statistical significance. Results 119 revision knee arthroplasty procedures were performed in the 8.5-year study period. 31 (26%) were for prosthetic joint infection (n=29 patients), n=2 patients had re-revision procedures for second PJI. Number of samples taken ranged from 1–12 with a mode of 6. N=27 (87%) cases had the recommended number of total samples taken, of these n= 20 (65%) had five or more samples taken, N=24 (77%) cases had three or more samples taken and n=18 (58%) had five or more samples. Conclusions Current management of infected knee arthroplasty presents great variability in intra-operative sampling technique. Sample collection adheres to national guidelines in 77% of cases. We recommend implementation of a standardised approach to sampling through inclusion of a five scalpel and five forceps pack specifically for sampling in theatre for all suspected PJI's.

Management of periprosthetic joint infection of shoulder arthroplasty: Single-stage versus two-stage protocols. A systematic review and meta-analysis of the literature.

The treatment of shoulder prosthetic joint infections (PJIs) requiring removal of the prosthesis is not well defined. This article aims to systematically review and compare the results of the literature in single-stage and two-stage protocols in the treatment of shoulder PJI. An in-depth search on PubMed/Scopus/Web of Science databases and cross-referencing search was carried out concerning the articles reporting detailed data on the topic. A total of 486 shoulder PJIs were included: 137 treated with single-stage and 349 with two-stage procedure. A similar distribution between early and not-early infections (19.1% vs 80.9%) was found between the two groups. The overall rate of success in terms of PJI eradication was significantly higher in the single-stage group (95.6% vs 85.7%, p < 0.001). The non-infection-related complications rate was 13.8% in the single-stage group and 37.6% in the two-stage group (p < 0.001), the non-infection-related revision rate was 8% and 18.9%, respectively (p = 0.005). The single-phase protocol showed a higher success rate in eradicating the infection and a lower complication rate. However, the low number of patients included, the low quality of the articles, the lack of data on clinical severity and bacteriological virulence suggest caution in conclusions.

Assessment of Microbiological and Clinical Findings of Two-Stage Revision Arthroplasty Performed Due to Prosthetic Joint Infection.

Two-stage revision arthroplasty remains the main surgical strategy for the treatment of prosthetic joint infections (PJI). Sonicate fluid culture has improved sensitivity compared to standard periprosthetic tissue culture, but its usefulness is questionable during the second stage of revision arthroplasty. Twenty-seven patients with prosthetic joint infection were investigated. Tissue and sonicate fluid cultures were examined to detect bacteria on the removed spacer during the second stage of exchange arthroplasty. Microbiological findings were analyzed and patients were assessed within an average of 5 years follow up. Tissue cultures in second-stage revision arthroplasties were positive in 6/27 cases (22.2%) growing CNS in 4 cases (14.8%), Staphylococcus aureus in 1 case (3.7%), and Enterococcus faecalis in 1 case (3.7%). In 3 cases (11.1%) infection was identified as a result of a sonication procedure. Clinical failures at final follow-up were recorded in 4 (14.8%) patients, with reinfection noted in 3 of them. Arthrodesis and spacer exchange followed by suppressive antibiotic therapy were performed in 2 cases. 1. Tissue cultures remain the gold standard in diagnosis of PIJ although a negative culture does not rule out the presence of bacteria on spacers removed during second stage revision for PJI. 2. Sonication appears to have limited ability to detect persistent infection before reimplantation and was not associated with recurrent infection; however, it can be considered a complementary method that could make it possible to identify new microorganisms and facilitate the selection of appropriate treatment options. 3. The positive results of sonication should be interpreted as the detection of actual pathogens in the light of the clinical, microbiological and histopathological data, especially for patients with immunodeficiency.

Prosthetic joint infection of the hip and knee due to Mycobacterium species: A systematic review.

BACKGROUND Mycobacterium species (Mycobacterium sp) is an emerging cause of hip and knee prosthetic joint infection (PJI), and different species of this organism may be responsible for the same.AIMTo evaluate the profile of hip and knee Mycobacterium PJI cases as published in the past 30 years.METHODSA literature search was performed in PubMed using the MeSH terms “Prosthesis joint infection” AND “Mycobacterium” for studies with publication dates from January 1, 1990, to May 30, 2021. To avoid missing any study, another search was performed with the terms “Arthroplasty infection” AND “Mycobacterium” in the same period as the previous search. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses chart was used to evaluate the included studies for further review. In total, 51 studies were included for further evaluation of the cases, type of pathogen, and treatment of PJI caused by Mycobacterium sp.RESULTSSeventeen identified Mycobacterium sp were reportedly responsible for hip/knee PJI in 115 hip/knee PJI cases, whereas in two cases there was no mention of any specific Mycobacterium sp. Mycobacterium tuberculosis (M. tuberculosis) was detected in 50/115 (43.3%) of the cases. Nontuberculous mycobacteria (NTM) included M. fortuitum (26/115, 22.6%), M. abscessus (10/115, 8.6%), M. chelonae (8/115, 6.9%), and M. bovis (8/115, 6.9%). Majority of the cases (82/114, 71.9%) had an onset of infection > 3 mo after the index surgery, while in 24.6% (28/114) the disease had an onset in ≤ 3 mo. Incidental intraoperative PJI diagnosis was made in 4 cases (3.5%). Overall, prosthesis removal was needed in 77.8% (84/108) of the cases to treat the infection. Overall infection rate was controlled in 88/102 (86.3%) patients with Mycobacterium PJI. Persistent infection occurred in 10/108 (9.8%) patients, while 4/108 (3.9%) patients died due to the infection.CONCLUSIONAt least 17 Mycobacterium sp can be responsible for hip/knee PJI. Although M. tuberculosis is the most common causal pathogen, NTM should be considered as an emerging cause of hip/knee PJI.

Efficacy of Three Povidone Iodine Formulations against Cutibacterium acnes Assessed through In Vitro Studies: A Preliminary Study.

Cutibacterium acnes (C. acnes, formerly known as Propionibacterium acnes) is the major causative agent of prosthetic joint infections (PJI). Treatment of PJI with antibiotics is difficult due to antibiotic resistance and adverse side effects on patients’ health. Proper disinfection of the surgical site using a variety of povidone iodine formulations could prevent C. acnes infection. In the current study, the efficacy of the three povidone iodine (PVP-I) formulations, viz: PVP-I 10% dermic solution, PVP-I 5% alcoholic solution and PVP-I 4% scrub, was tested against C. acnes, in vitro, in the presence of interfering substances mimicking soiling conditions. C. acnes strain ATCC 6919 was used to test the bactericidal activity of the povidone iodine formulations according to the modified dilution-neutralization method described in French Norm EN standard 13727. A 3-log reduction in the bacterial cell count in 60 s was considered to be significant. The results showed that under experimental conditions, the three PVP-I formulations displayed bactericidal activity against the micro-organism, Cutibacterium acnes, and that the lowest concentration of povidone-iodine active against C. acnes was 0.4%. These results are encouraging as PVP-I offers a low-cost and efficient method of disinfection.