The Not-So-Good Prognosis of Streptococcal Periprosthetic Joint Infection Managed by Implant Retention: The Results of a Large Multicenter Study

How to manage treatment failure in prosthetic joint infection

BACKGROUND

Management for prosthetic joint infections remains a challenging area for both infectious diseases and orthopaedic surgery, particularly in the setting of treatment failure. This is compounded by a lack of level 1 evidence to guide approaches. The optimal management of prosthetic joint infections requires a multi-disciplinary approach combined with shared decision making with the patient.

AIMS

This article describes the approach to prosthetic joint infections in the setting of treatment failure.

SOURCES

Narrative review based on literature review from PubMed. There was no time limit on the studies included. In addition, the reference list for included studies were reviewed for literature saturation with manual searching of clinical guidelines. Management approaches described incorporate evidence- and eminence-based recommendations from expert guidelines and clinical studies, where applicable.

CONTENT

The surgical and antimicrobial approaches for prosthetic joint infections are described for first-line treatment of prosthetic joint infections and approaches in the event of treatment failure. Management approaches are based on an understanding of the role the biofilm plays in the pathogenesis of prosthetic joint infections. The management of these infections aims to fulfil two key goals: to eradicate the biofilm-associated microorganisms and, to maintain a functional joint and quality of life. In treatment failure, these goals are not always feasible, and the role of the multi-disciplinary team and shared-decision making are prominent.

IMPLICATIONS

Prosthetic joint surgery is a high-volume surgery, and the demand for this surgery is continually increasing. With this, the number of infections requiring expert care will also increase. Eminence-based management approaches have been established to guide treatment failure until knowledge gaps in optimal management are addressed by well-designed, clinical trials.

Intestinal methicillin-resistant Staphylococcus aureus causes prosthetic infection via 'Trojan Horse' mechanism: Evidence from a rat model

Aims

Methicillin-resistant Staphylococcus aureus (MRSA) can cause wound infections via a 'Trojan Horse' mechanism, in which neutrophils engulf intestinal MRSA and travel to the wound, releasing MRSA after apoptosis. The possible role of intestinal MRSA in prosthetic joint infection (PJI) is unknown.

Methods

Rats underwent intestinal colonization with green fluorescent protein (GFP)-tagged MRSA by gavage and an intra-articular wire was then surgically implanted. After ten days, the presence of PJI was determined by bacterial cultures of the distal femur, joint capsule, and implant. We excluded several other possibilities for PJI development. Intraoperative contamination was excluded by culturing the specimen obtained from surgical site. Extracellular bacteraemia-associated PJI was excluded by comparing with the infection rate after intravenous injection of MRSA or MRSA-carrying neutrophils. To further support this theory, we tested the efficacy of prophylactic membrane-permeable and non-membrane-permeable antibiotics in this model.

Results

After undergoing knee surgery eight or 72 hours after colonization, five out of 20 rats (25.0%) and two out of 20 rats (10.0%) developed PJI, respectively. Strikingly, 11 out of 20 rats (55.0%) developed PJI after intravenous injection of MRSA-carrying neutrophils that were isolated from rats with intestinal MRSA colonization. None of the rats receiving intravenous injections of MRSA developed PJI. These results suggest that intestinal MRSA carried by neutrophils could cause PJI in our rat model. Ten out of 20 (50.0%) rats treated with non-membrane-permeable gentamicin developed PJI, whereas only one out of 20 (5.0%) rats treated with membrane-permeable linezolid developed PJI.

Conclusion

Neutrophils as carriers of intestinal MRSA may play an important role in PJI development.Cite this article: Bone Joint Res. 2020;9(4):152-161.

Beta-hemolytic group a streptococcal orthopaedic infections: Our institutional experience and review of the literature

Group A streptococcal (GAS) infections have high morbidity and mortality due to toxin production and tissue invasion. We reviewed all orthopaedic GAS infections at our medical centre between January 2017 and April 2019. Median age was 56 years. At least 60% had a body mass index (BMI) of ≥30 kg/m². Median Charlson comorbidity score was 3 (range 0-7). Clinical cure at 90 days was achieved in only 62%. All 4 patients with underlying orthopaedic hardware were cured. Toxin-neutralizing antibiotics and intravenous immunoglobulin were underutilized. Our review confirms poor outcomes from GAS orthopaedic infections without optimal management.

Second Periprosthetic Joint Infection Caused by Streptococcus dysgalactiae: How Genomic Sequencing Can Help Defining the Best Therapeutic Strategy

Primary and revision arthroplasties are increasing worldwide, as are periprosthetic joint infections (PJI). The management of PJI requires surgery, the strategy of which is dictated by the acute or chronic nature of the infection, with an exchange of the implant in the event of a chronic PJI or in the case of recurrence with the same pathogen. We report the case of a 63-year-old man with two episodes of Streptococcus dysgalactiae subsp. equisimilis PJI within 9 months. Based on clinical suspicion of an haematogenous PJI, the patient was treated by DAIR (debridement, antibiotics, implant retention), while genomic sequencing revealed two different strains, confirming our hypothesis that no additional surgery was needed. Hence, we report a case where genomic analysis was decisive for the decision of the best therapeutic strategy.

Recommendations for Systemic Antimicrobial Therapy in Fracture-Related Infection: A Consensus From an International Expert Group

Fracture-related infection (FRI) is a major complication in musculoskeletal trauma and one of the leading causes of morbidity. Standardization of general treatment strategies for FRI has been poor. One of the reasons is the heterogeneity in this patient population, including various anatomical locations, multiple fracture patterns, different degrees of soft-tissue injury, and different patient conditions. This variability makes treatment complex and hard to standardize. As these infections are biofilm-related, surgery remains the cornerstone of treatment, and this entails multiple key aspects (eg, fracture fixation, tissue sampling, debridement, and soft-tissue management). Another important aspect, which is sometimes less familiar to the orthopaedic trauma surgeon, is systemic antimicrobial therapy. The aim of this article is to summarize the available evidence and provide recommendations for systemic antimicrobial therapy with respect to FRI, based on the most recent literature combined with expert opinion. LEVEL OF EVIDENCE:: Therapeutic Level V. See Instructions for Authors for a complete description of levels of evidence.

Risk of Recurrent Staphylococcus aureus Prosthetic Joint Infection in Rheumatoid Arthritis Patients-A Nationwide Cohort Study

Background

Treatment of rheumatoid arthritis (RA) often involves immune-suppressive therapies. Concern for recurrent prosthetic joint infection (PJI) in RA patients might be high and could reduce use of joint implantation in these patients. We aimed to evaluate the risk of recurrence of PJI in RA patients compared with osteoarthritis (OA) patients by utilizing a large health care system.

Methods

We conducted a retrospective cohort study of all patients admitted for a Staphylococcus aureus PJI who underwent debridement, antibiotics, and implant retention (DAIR) or 2-stage exchange (2SE) between 2003 and 2010 at 86 Veterans Affairs Medical Centers. Both RA patients and the comparison group of osteoarthritis (OA) patients were identified using International Classification of Diseases, Ninth Revision, codes. All index PJI and recurrent positive cultures for S. aureus during 2 years of follow-up were validated by manual chart review. A Cox proportional hazards regression model was used to compare the time to recurrent PJI for RA vs OA.

Results

In our final cohort of 374 veterans who had either DAIR or 2SE surgery for their index S. aureus PJI, 11.2% had RA (n = 42). The majority of the cohort was male (97.3%), and 223 (59.6%) had a methicillin-susceptible S. aureus PJI. RA patients had a similar risk of failure compared with OA patients, after adjusting for covariates (hazard ratio, 0.81; 95% confidence interval, 0.48–1.37).

Conclusions

Prior diagnosis of RA does not increase the risk of recurrent S. aureus PJI. Further studies are needed to evaluate the effect of different RA therapies on outcomes of episodes of PJI.

Use of gentamicin-impregnated beads or sponges in the treatment of early acute periprosthetic joint infection: a propensity score analysis

Objectives

Early acute periprosthetic joint infections (PJIs) treated with debridement, antibiotics and implant retention (DAIR) have failure rates ranging from 10% to 60%. We determined the efficacy of applying local gentamicin-impregnated beads and/or sponges during debridement in early PJI.

Methods

Patients with early acute PJI, defined as less than 21 days of symptoms and treated with DAIR within 90 days after index surgery, were retrospectively evaluated. Early failure was defined as PJI-related death, the need for implant removal or a second DAIR or antibiotic suppressive therapy owing to persistent signs of infection, all within 60 days after initial debridement. Overall failure was defined as implant removal at any timepoint during follow-up. A 1:1 propensity score matching was performed to correct for confounding factors.

Results

A total of 386 patients were included. Local gentamicin was applied in 293 patients (75.9%) and was withheld in 93 patients (24.1%). Multivariate analysis demonstrated that the use of local gentamicin was independently associated with early failure (OR = 1.97, 95% CI = 1.12-3.48). After propensity matching, early failure was 40.3% in the gentamicin group versus 26.0% in the control group (P = 0.06) and overall failure was 5.2% in the gentamicin group versus 2.6% in the control group (P = 0.40). These numbers remained when solely analysing the application of gentamicin-impregnated sponges.

Conclusions

Even after propensity score matching, failure rates remained higher if local gentamicin-impregnated beads and/or sponges were administered in early acute PJI. Based on these results, their use should be discouraged.

Long-term antimicrobial suppression prevents treatment failure of streptococcal periprosthetic joint infection

OBJECTIVES

To evaluate the effect of oral antimicrobial suppression on the outcome of streptococcal periprosthetic joint infection (PJI).

METHODS

Consecutive patients with streptococcal PJI receiving antimicrobial suppression for >6 months were prospectively included and compared to a retrospective control group without suppression. Outcome was assessed with Kaplan-Meier analysis and compared by the log-rank Mantel-Cox test. Multivariate analysis was used to identify factors associated with treatment failure.

RESULTS

Of 69 streptococcal PJI episodes (37 knee, 31 hip and one shoulder PJI), 43 (62%) were caused by beta-hemolytic streptococci and 26 (38%) by viridans group streptococci. Debridement and prosthesis retention was performed in 27 (39%), one-stage exchange in 5 (7%), multi-stage exchange in 31 (44%) and prosthesis removal in 6 patients (9%). 24 patients (35%) were treated with antimicrobial suppression receiving oral amoxicillin (n = 22), doxycycline (n = 1) or clindamycin (n = 1). After a median follow-up of 13 months (range, 0.5-111 months), 38 of 65 patients (58%) were infection-free. Suppressive antimicrobial treatment was associated with higher success rate compared with no suppression (93% vs. 57%, p = 0.002), representing the only significant independent factor preventing treatment failure.

CONCLUSIONS

Long-term antimicrobial suppression was associated with significantly better treatment outcome and should be strongly considered in streptococcal PJI.

Moxifloxacin-rifampicin combination for the treatment of non-staphylococcal Gram-positive orthopedic implant-related infections

OBJECTIVE

We aimed to describe the effectiveness and safety of the moxifloxacin-rifampicin combination in non-staphylococcal Gram-positive orthopedic implant-related infections.

METHODS

Patients treated with the moxifloxacin-rifampicin combination for an implant-related infection from November 2014 to November 2016 were retrospectively identified from the database of the referral centers for bone and joint infections in Western France.

RESULTS

Twenty-three cases of infection due to Streptococcus spp. (n=12), Cutibacteriumacnes (n=6), and Enterococcus faecalis (n=5) were included. Ten patients with hip prosthesis were included. Infection was polymicrobial in 11 cases. According to the MIC, moxifloxacin was 1.5 to 11.7 times as active as levofloxacin against non-staphylococcal Gram-positive bacteria. We reported an 81.8% success rate, and no severe adverse effect.

CONCLUSION

The moxifloxacin-rifampicin combination is a valuable alternative for the treatment of non-staphylococcal Gram-positive implant-related infections because of the good activity of moxifloxacin against these bacteria and the potential activity on the biofilm.

The prognosis of streptococcal prosthetic bone and joint infections depends on surgical management-A multicenter retrospective study

BACKGROUND

The optimal treatment of streptococcal prosthetic joint infections (PJIs) is unclear.

METHODS

A cohort of streptococcal PJIs was reviewed retrospectively in seven reference centers for the management of complex bone and joint infections, covering the period January 1, 2010 to December 31, 2012.

RESULTS

Seventy patients with monomicrobial infections were included: 47 had infections of total hip arthroplasty and 23 had infections of total knee arthroplasty. The median age was 77 years (interquartile range (IQR) 69-83 years), the median Charlson comorbidity score was 4 (IQR 3-6), and 15.6% (n=11) had diabetes. The most commonly identified streptococcal species were Streptococcus agalactiae and Streptococcus dysgalactiae (38.6% (n=27) and 17.1% (n=12), respectively). Debridement, antibiotics and implant retention (DAIR) was performed after a median time of 7 days (IQR 3-8 days), with polyethylene exchange (PE) in 21% of cases. After a minimum follow-up of 2 years, 27% of patients had relapsed, corresponding to 51.4% of DAIR treatment cases and 0% of one-stage (n=15) or two-stage (n=17) exchange strategy cases. Rifampicin or levofloxacin in combination therapy was not associated with a better outcome (adjusted p= 0.99). S. agalactiae species and DAIR treatment were associated with a higher risk of failure. On multivariate analysis, only DAIR treatment and S. agalactiae were independent factors of relapse. Compared to DAIR without PE, DAIR with PE was only associated with a trend towards a benefit (odds ratio 0.33, 95% confidence interval 0.06-1.96; adjusted p= 0.44).

CONCLUSIONS

Streptococcal PJIs managed with DAIR have a poor prognosis and S. agalactiae seems to be an independent factor of treatment failure.

Haematogenous prosthetic knee infections: Prospective cohort study of 58 patients

BACKGROUND

Prosthetic joint infection (PJI) is a rare (incidence, 0.15% to 0.9%) but serious complication of knee arthroplasty. Haematogenous PJI of the knee (KhPJI) which accounts for 10% of cases, has been less studied than PJI due to other mechanisms. The primary objective of this study in patients with KhPJI of the knee was to determine the 2-year infection eradication failure rate after either exchange arthroplasty or arthrotomy/synovectomy/irrigation (ASI), combined with prolonged peri-operative antibiotic therapy, at a referral centre for complex osteo-articular infections.

HYPOTHESIS

ASI within 2 weeks after symptom onset and one-stage exchange arthroplasty produce similar 2-year success rates in patients with KhPJI of the knee.

MATERIAL AND METHODS

A prospective observational cohort study was performed in patients managed for PJI of the knee between 2003 and 2015. The primary outcome measure was the occurrence of a septic event or of KhPJI -related death during a minimum follow-up of 2 years.

RESULTS

Of 265 patients with PJI after total knee arthroplasty, 58 (22.1%) had KhPJI with onset more than 3 months after the last arthroplasty procedure and were included in the study. Among them, one-third had immune deficiencies. The most common causative organisms were streptococci (n=25, 43%) and Staphylococcusaureus (n=20, 34%). The primary focus of infection was identified in only 64% of patients and was most often cutaneous (n=19, 33%) or dental (n=11, 19%). A septic event or KhPJI-related death occurred in 5/34 (15%) patients after one-stage exchange arthroplasty and 6/19 (32%) patients after ASI within 15 days after symptom onset (p=0.03). Patient characteristics, type of prosthesis, and causative organism were not significantly associated with failure to eradicate the infection.

CONCLUSION

ASI carried a high failure rate despite being performed within 15 days after symptom onset. One-stage exchange arthroplasty seems to be the best surgical option, particularly as the exact time of symptom onset may be difficult to determine. Identifying and eradicating the primary focus of infection is crucial.

LEVEL OF EVIDENCE

II, low-powered prospective cohort study.

The Different Microbial Etiology of Prosthetic Joint Infections according to Route of Acquisition and Time after Prosthesis Implantation, Including the Role of Multidrug-Resistant Organisms

The aim of our study was to characterize the etiology of prosthetic joint infections (PJIs)-including multidrug-resistant organisms (MDRO)-by category of infection. A multicenter study of 2544 patients with PJIs was performed. We analyzed the causative microorganisms according to the Tsukayama's scheme (early postoperative, late chronic, and acute hematogenous infections (EPI, LCI, AHI) and "positive intraoperative cultures" (PIC)). Non-hematogenous PJIs were also evaluated according to time since surgery: <1 month, 2-3 months, 4-12 months, >12 months. AHIs were mostly caused by Staphylococcus aureus (39.2%) and streptococci (30.2%). EPIs were characterized by a preponderance of virulent microorganisms (S. aureus, Gram-negative bacilli (GNB), enterococci), MDROs (24%) and polymicrobial infections (27.4%). Conversely, coagulase-negative staphylococci (CoNS) and Cutibacterium species were predominant in LCIs (54.5% and 6.1%, respectively) and PICs (57.1% and 15.1%). The percentage of MDROs isolated in EPIs was more than three times the percentage isolated in LCIs (7.8%) and more than twice the proportion found in AHI (10.9%). There was a significant decreasing linear trend over the four time intervals post-surgery for virulent microorganisms, MDROs, and polymicrobial infections, and a rising trend for CoNS, streptococci and Cutibacterium spp. The observed differences have important implications for the empirical antimicrobial treatment of PJIs.

Streptococcus salivarius Prosthetic Joint Infection following Dental Cleaning despite Antibiotic Prophylaxis

We present the case of a 92-year-old man with septic arthritis of a prosthetic hip joint due to Streptococcus salivarius one week following a high-risk dental procedure despite preprocedure amoxicillin. S. salivarius is a commensal bacterium of the human oral mucosa that is an uncommon cause of bacteremia. S. salivarius has previously been described as a causative agent of infective endocarditis and spontaneous bacterial peritonitis but was only recently recognized as a cause of prosthetic joint infection. This case highlights the potential pathogenicity of a common commensal bacteria and the questionable utility of prophylactic antibiotics before dental procedures to prevent periprosthetic joint infections.

Increased Failure After Irrigation and Debridement for Acute Hematogenous Periprosthetic Joint Infection

BACKGROUND

Acute periprosthetic joint infection (PJI) is difficult to treat. In this study, we investigated the failure rates of irrigation and debridement (I&D) among patients with acute post-surgical and acute hematogenous PJI, and explored various host and organism-related risk factors that may be associated with treatment failure.

METHODS

We retrospectively reviewed the cases of 199 total joint arthroplasty patients who underwent I&D for acute post-surgical PJI (<3 months postoperatively) and acute hematogenous PJI (≥3 months postoperatively, with abrupt symptoms lasting <3 weeks) at a single center during the period of 2005 to 2016. Only patients meeting the Musculoskeletal Infection Society (MSIS) criteria for PJI were included. Patient demographics, comorbidities, physical examination findings, laboratory results, and organism profile were identified. Treatment failure, as defined by the Delphi criteria, was determined for 1-year follow-up. Primary statistical analysis involved univariate and multivariate regression.

RESULTS

The failure rate was 37.7% (75 of 199) at 1 year. Among the patients with acute hematogenous infections, the rate of failure (56%, 29 of 52) was almost 2 times higher than that of patients with acute post-surgical infections (31%, 46 of 147) (adjusted odds ratio [OR], 2.36; 95% confidence interval [CI], 1.16 to 4.81; p = 0.018). Host predictors of failure included prior revision surgery (adjusted OR, 2.55; 95% CI, 1.22 to 5.32; p = 0.013) and a higher Charlson Comorbidity Index (adjusted OR, 1.22; 95% CI, 1.01 to 1.51; p = 0.048). Specific comorbidities associated with failure included chronic obstructive pulmonary disease (p = 0.026), diabetes (p = 0.004), and a history of malignancy (p = 0.005). Patients with polymicrobial infections (adjusted OR, 2.40; 95% CI, 1.10 to 5.20; p = 0.028) were also more likely to experience failure of treatment after I&D. The clinical and laboratory risk factors associated with failure were the presence of intraoperative purulence (p = 0.05), elevated systolic blood pressure (p = 0.05), tachycardia (p = 0.06), and higher serum C-reactive protein level (p = 0.003).

CONCLUSIONS

This study revealed that I&D is associated with a high rate of failure for patients with an acute hematogenous PJI. The study also identified a number of risk factors for failure. The findings of this study may allow better decision-making by surgeons regarding the surgical management of patients with acute PJI.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Studying Biofilm and Clinical Issues in Orthopedics

The association between biofilm-forming microorganisms and prosthetic joint infection influences all aspect of management including approaches to diagnosis, management and prevention. This article will provide an overview of new anti-biofilm strategies for management of prosthetic joint infection.

The Benefice of Mobile Parts' Exchange in the Management of Infected Total Joint Arthroplasties with Prosthesis Retention (DAIR Procedure)

Background: The management of prosthetic joint infections (PJI) with debridement and retention of the implant (DAIR) has its rules. Some authors claim that lacking the exchange of mobile prosthetic parts is doomed to failure, while others regard it as optional. Methods: Single-center retrospective cohort in PJIs treated with DAIR. Results: We included 112 PJIs (69 total hip arthroplasties, 9 medullary hip prostheses, 41 total knee arthroplasties, and 1 total shoulder arthroplasty) in 112 patients (median age 75 years, 52 females (46%), 31 (28%) immune-suppressed) and performed a DAIR procedure in all cases-48 (43%) with exchange of mobile parts and 64 without. After a median follow-up of 3.3 years, 94 patients (84%) remained in remission. In multivariate Cox regression analysis, remission was unrelated to PJI localization, pathogens, number of surgical lavages, duration of total antibiotic treatment or intravenous therapy, choice of antibiotic agents, immune-suppression, or age. In contrast, the exchange of mobile parts was protective (hazard ratio 1.9; 95% confidence interval 1.2⁻2.9). Conclusions: In our retrospective single-center cohort, changing mobile parts of PJI during the DAIR approach almost doubled the probability for long-term remission.

Clinical outcome and risk factors for failure in late acute prosthetic joint infections treated with debridement and implant retention

OBJECTIVES

Debridement, antibiotics and implant retention (DAIR) is the recommended treatment for all acute prosthetic joint infections (PJI), but its efficacy in patients with late acute (LA) PJI is not well described.

METHODS

Patients diagnosed with LA PJI between 2005 and 2015 were retrospectively evaluated. LA PJI was defined as the development of acute symptoms (≤ 3 weeks) occurring ≥ 3 months after arthroplasty. Failure was defined as: (i) the need for implant removal, (ii) infection related death, (iii) the need for suppressive antibiotic therapy and/or (iv) relapse or reinfection during follow-up.

RESULTS

340 patients from 27 centers were included. The overall failure rate was 45.0% (153/340). Failure was dominated by Staphylococcus aureus PJI (54.7%, 76/139). Significant independent preoperative risk factors for failure according to the multivariate analysis were: fracture as indication for the prosthesis (odds ratio (OR) 5.4), rheumatoid arthritis (OR 5.1), age above 80 years (OR 2.6), male gender (OR 2.0) and C-reactive protein > 150 mg/L (OR 2.0). Exchanging the mobile components during DAIR was the strongest predictor for treatment success (OR 0.35).

CONCLUSION

LA PJIs have a high failure rate. Treatment strategies should be individualized according to patients' age, comorbidity, clinical presentation and microorganism causing the infection.

Infection after Constrained Condylar Knee Arthroplasty: Incidence and microbiological findings in 100 consecutive complex primary and revision total knee arthroplasties

Background: To report incidence, microbiological findings, and treatment outcome of prosthetic joint infection (PJI) after constrained condylar knee arthroplasty.

Methods: Retrospective study of 100 consecutive complex primary and revision total knee arthroplasties operated with constrained condylar knee arthroplasties between February 2006 and October 2015 at a single institution. Demographic and surgical data were registered, as well as data regarding infection, microbiology and treatment. Follow-up median 43 months; SD 32.

Results: The overall incidence of acute postoperative PJI was low (3/100). 1/33 (3%), 1/ 45 (2%), and 1/22 (5%), following primary complex TKA, aseptic revisions, and septic revisions, respectively. The incidence of late acute hematogenous PJI was 5/100. 1/33 (3%),1/45 (2%), and 3/22 (14%) following primary complex TKA, aseptic revisions, and septic revisions, respectively. Late acute hematogenous infections were associated with a lower success rate of treatment with debridement and implant retention compared with acute postoperative PJIs, 1/5 versus 2/3.

Conclusion: The risk of late acute hematogenous infections seems increased. Multiple previous surgery, poor soft tissue, and large metal implants may contribute to an increased lifelong susceptibility for bacteremias to cause PJIs.

Salvage Debridement, Antibiotics and Implant Retention ("DAIR") With Local Injection of a Selected Cocktail of Bacteriophages: Is It an Option for an Elderly Patient With Relapsing Staphylococcus aureus Prosthetic-Joint Infection?

Local injection of a bacteriophages mix during debridement, antibiotics and implant retention ("DAIR") was performed to treat a relapsing Staphylococcus aureus chronic prosthetic joint infection (PJI). This salvage treatment was safe and associated with a clinical success. Scientific evaluation of the potential clinical benefit of bacteriophages as antibiofilm treatment in PJI is now feasible and required.

Erysipelas or cellulitis with a prosthetic joint in situ

We describe a case of a 60-year old male who developed an acute prosthetic joint infection (PJI) of the knee, secondary to erysipelas of the lower leg due to beta-hemolytic Group G streptococci. As it is unknown how often this phenomenon occurs in patients with prosthetic implants and which patients are most prone to develop this complication, we analyzed: i) the incidence of the development of a PJI in these patients and ii) the clinical characteristics of streptococcal PJI during an episode of erysipelas/cellulitis. Based on a retrospective analysis of patients with a prosthetic implant in situ presenting at the emergency department with erysipelas/cellulitis, 1 out of 10 patients developed a PJI. An additional analysis within a multicenter cohort on streptococcal PJI demonstrated in 22 patients that a secondary PJI due to erysipelas/cellulitis mostly develops in young implants (<5 years old). In 20 cases (91%), the skin infection was in the same limb as the joint prosthesis suggesting contiguous spread of bacteria. These data emphasizes the importance of preventive measures to reduce the occurrence of skin infections in patients with prosthetic implants, and if an erysipelas or cellulitis does occur, to monitor patients carefully.

Procedure for single-stage implant retention for chronic periprosthetic infection using topical degradable calcium-based antibiotics

INTRODUCTION

Surgical treatment using DAIR (debridement, systemic antibiotics, and implant retention) can lead to high rates of treatment success in cases of early periprosthetic joint infection (PJI) but can fail in late-onset cases. Supplementary local antibiotic therapy is not yet generally established and lacks evidence-based proof of efficacy. The aim of this study was to analyze DAIR outcomes in recurrent PJI cases and patients who are not suitable for a two-stage exchange, using additional degradable calcium-based antibiotics.

METHODS

All patients fulfilled the Infectious Diseases Society of America (IDSA) guidelines for chronic late-onset PJI but were not suitable for a multistage procedure because of their individual operation risk. A total of 42 patients (mean age, 73 years) were treated using a single-stage algorithm consisting of DAIR, followed by implantation of degradable antibiotics chosen in accordance with an antibiogram. OSTEOSET® (admixed ceftriaxone/vancomycin/tobramycin) and Herafill-Gentamycin® were used as carrier systems. The follow-up period was 23 months (± SD, 10.3). The study is based on institutional review board (IRB) approval.

RESULTS

The clinical entities were chronic PJI of the hip (45.2%), knee (28.6%), and knee arthrodesis (26.2%). The bacterial spectrum was composed of Staphylococcus epidermidis (29%), Staphylococcus aureus (21%), and Enterococcus faecalis (21%). 21.4% showed a combination of two or more bacteria. In 73.8%, permanent remission was achieved, while 11.9% showed chronic PJI under implant retention. Implant retention could be achieved in 85.7%.

CONCLUSION

DAIR usually shows low levels of success in difficult-to-treat cases. However, we could demonstrate the successful treatment of patients with recurrent PJI (typically considered DAIR-inappropriate) using degradable antibiogram-based topical calcium-based antibiotics. Over 70% of the cases went to remission and over 85% of the implants could be retained.

Treatment of Prosthetic Joint Infection with Debridement, Antibiotics and Irrigation with Implant Retention - a Narrative Review

Prosthetic joint infection usually requires combined medical and surgical therapy. While revision surgery is widely considered to be the gold standard surgical procedure, debridement, antibiotics and irrigation with implant retention is a very appealing alternative. There is however great controversy regarding its real worth with success rates ranging from 0% to over 90%. A number of different patient and host related variables as well as specific aspects of surgical and medical management have been described as relevant for the final outcome. Along this paper, the authors will provide the readers with a critical narrative review of the currently available literature while trying to provide concise and practical treatment recommendations regarding adequate patient selection criteria, proper surgical technique and optimal antibiotic therapy.

Bacterial colonisation of suture material after routine neurosurgical procedures: relevance for wound infection

BACKGROUND

Wound healing impairment is a serious problem in surgical disciplines which may be associated with chronic morbidity, increased cost and patient discomfort. Here we aimed to investigate the relevance of bacterial colonisation on suture material using polymerase chain reaction (PCR) to detect and taxonomically classify bacterial DNA in patients with and without wound healing problems after routine neurosurgical procedures.

METHODS

Repeat surgery was performed in 25 patients with wound healing impairment and in 38 patients with well-healed wounds. To determine the presence of bacteria, a 16S rDNA-based PCR detection method was applied. Fragments of 500 bp were amplified using universal primers which target hypervariable regions within the bacterial 16S rRNA gene. Amplicons were separated from each other by single-strand conformation polymorphism (SSCP) analysis, and finally classified using Sanger sequencing.

RESULTS

PCR/SSCP detected DNA of various bacteria species on suture material in 10/38 patients with well-healed wounds and in 12/25 patients with wound healing impairment including Staphylococcus aureus, Staphylococcus epidermidis, Propionibacterium acnes and Escherichia coli. Microbiological cultures showed bacterial growth in almost all patients with wound healing impairment and positive results in PCR/SSCP (10/12), while this was the case in only one patient with a well-healed wound (1/10).

CONCLUSIONS

Colonisation of suture material with bacteria occurs in a relevant portion of patients with and without wound healing impairment after routine neurosurgical procedures. Suture material may provide a nidus for bacteria and subsequent biofilm formation. Most likely, however, such colonisation of sutures is not a general primer for subsequent wound infection.

Analysis of postoperative and hematogenous prosthetic joint-infection microbiological patterns in a large cohort

OBJECTIVES

This study was undertaken to analyze prosthetic joint infection (PJI)-causing microorganisms and compare their distribution patterns according to PJI classification.

METHODS

Cohort study from a single referral center for bone-and-joint infections from January 2004 to December 2015.

RESULTS

Nine hundred and twenty-six patients, who developed 997 PJIs, involving the hip (62%), knee (35%) and/or shoulder (1%), were included. PJIs were classified as early postoperative (19%), late chronic (30%), hematogenous (35%) and undetermined (16%). Pathogens most frequently isolated from early-postoperative PJIs were staphylococci (57%), with 25% each Staphylococcus aureus or Staphylococcus epidermidis; 21% were polymicrobial and 10% Gram-negative rods. For late-chronic PJIs, the most frequent microbes were staphylococci (61%), predominantly S. epidermidis (35%); anaerobic bacteria were isolated from 15%; 11% were polymicrobial. Hematogenous PJIs were 99% monomicrobial. Although S. aureus was the most frequently isolated species (28%), streptococci were isolated slightly more often than staphylococci (39% vs. 36%). Among streptococci, group B streptococci were the most frequent (15%). The portal of entry was identified for 52% of hematogenous PJIs: 15% cutaneous, 11% dental, 9% gastrointestinal, 6% urinary, and 11% miscellaneous.

CONCLUSION

Although a wide variety of microorganisms was isolated from PJIs, specific microbiological patterns were observed according to infection classification.