The application of sonication in diagnosis of periprosthetic joint infection

Periprosthetic joint infection (PJI) is a catastrophic complication after total joint arthroplasty. It has always been difficult to diagnose PJI, which is characterised by existence of biofilm around the implants. The application of sonication has proven advantageous for pathogen detection. This meta-analysis of clinical trials was performed to evaluate the diagnostic value of sonication and to compare it with traditional bacterial culture. We assessed 16 studies that evaluated sonication fluid cultures (SFC) for the diagnosis of PJI. It was shown that sonication may be of great value in PJI diagnosis, with a pooled sensitivity of 0.79 (95 % confidence interval [CI]?=?0.76–0.81), specificity of 0.95 (CI?=?0.94–0.96), DOR of 71.20 (CI?=?31.08–163.10), PLR of 15.25 (CI?=?6.44–36.15), and NLR of 0.23 (CI?=?0.18–0.30). The AUC value of the SROC was 0.90. The results of this meta-analysis showed that culture of fluid after sonication was of great value for PJI diagnosis. Sonication was more sensitive than traditional tissue culture with lower specificity, especially for patients previously taking antibiotics.     

Evaluation of quantitative analysis of cultures from sonicated retrieved orthopedic implants in diagnosis of orthopedic infection

To improve the microbiological diagnosis of device-related osteoarticular infections, we have developed a protocol based on the sonication of device samples, followed by concentration and inoculation of the sonicate in a broad variety of media in a quantitative manner. Sixty-six samples from 31 patients were included in the study (17 of them with clinical diagnosis of infection). The sonication procedure had a sensitivity of 94.1%, which is better than that of conventional cultures (88.2%). One case of contamination and six cases of unexpected positive cultures were detected (specificity of 42.8%): two of these were considered to represent true infection, while the other four were considered to be nonsignificant (corrected specificity of 50%), although the clinical importance of these isolates is questionable. When we analyzed the number of CFU, no breakpoint between significant and nonsignificant isolates could be established. Based on our results, the procedure of sonication of retrieved implants is better than conventional cultures for the diagnosis of device-related infections. The significance of some isolates in patients without clinical infection remains uncertain. However, they may become pathogens and cannot be routinely considered to be contamination.     

The utility of dithiothreitol treatment of periprosthetic tissues and explanted implants in the diagnosis of prosthetic joint infection

PurposeThe methods used for the processing of periprosthetic tissues and explanted implants to improve culture outcome especially in biofilm mediated prosthetic joint infections (PJIs) are still debated upon. Studies have reported that Dithiothreitol (DTT) pretreatment of infected devices gives similar results as sonication. However, none of them evaluated the DTT treatment of periprosthetic tissues and explanted implants in the same cohort. We evaluated the diagnostic utility of DTT treatment of periprosthetic tissue and explanted implants, as compared to the normal saline treatment of periprosthetic tissues and sonication of explanted implants for the diagnosis of PJI.MethodsSeventy-three revision arthroplasty cases were prospectively included in this study. Three to five tissue specimens and the explanted implants were collected from each patient. Periprosthetic tissue samples were processed by both normal saline and DTT treatments. Explanted implants were subjected to both DTT treatment and sonication. Musculoskeletal Infection Society (MSIS) PJI criteria was used as the reference standard for the diagnosis of PJI.ResultsOf the 73 cases enrolled, 34 had PJI and 39 were aseptic failures. The sensitivity of DTT treated periprosthetic tissue culture (PTC) and saline treated PTC was similar (66.6% vs 58.8%, P = 0.25). The specificity of both was 100%. Sonication and DTT treatment of explanted implants showed comparable sensitivity (85.3% vs 82.4%) and specificity (100% vs 97.4%), P > 0.99. Compared to DTT treated PTC, culture of DTT treated explanted implants significantly improved the diagnosis of PJI (P = 0.03).ConclusionsWe could verify that DTT can be used to improve culture outcome in laboratories where biofilm detaching sonication techniques are not available for infected implants. In addition, we showed that it is possible to use DTT for treating tissue biopsies, but larger studies are required to confirm our findings.     

Optimization of periprosthetic culture for diagnosis of Propionibacterium acnes prosthetic joint infection

Propionibacterium acnes is increasingly recognized as an important agent of prosthetic joint infection (PJI). However, the optimum culture conditions for recovery of this organism from PJI specimens have not been determined. By applying a prolonged 28-day culture incubation to all periprosthetic specimens received for bacterial culture from 198 revision arthroplasty procedures, we retrospectively determined that a 13-day culture incubation period is necessary for the recovery of P. acnes from patients with PJI. Incubation beyond this period was associated with increasing recovery of nondiagnostic isolates: 21.7% of P. acnes isolates believed to be clinically unimportant were recovered after 13 days of incubation. Importantly, a diagnosis of P. acnes PJI would have been missed in 29.4% of patients had extended culture incubation been applied only to anaerobic culture media. Although specimens from P. acnes PJIs were more commonly associated with the presence of ≥ 2 culture media positive for growth, acute inflammation (≥ 5 neutrophils/high-power field) was observed in only 40% of patients with PJIs that had more than one specimen submitted for bacterial culture. These results support the need for a minimum culture incubation period of 13 days to be applied to both aerobic and anaerobic culture media for all periprosthetic specimens. Optimal recovery of infecting organisms from PJI specimens will be an important component in generating a universal definition for PJI due to indolent agents of infection, such as P. acnes.     

Microbiological diagnosis of prosthetic joint infections: a prospective evaluation of four bacterial culture media in the routine laboratory

The diagnosis of prosthetic joint infection (PJI) in the routine microbiology laboratory is labour-intensive, but semi-automated methods may be appropriate. We prospectively compared four microbiological culture methods on samples taken at prosthetic joint revision surgery. Automated BACTEC blood culture bottles and cooked meat enrichment broth were the most sensitive methods (87% and 83%, respectively, as compared with fastidious anaerobic broth (57%) and direct plates (39%)); all were highly specific (97–100%). To our knowledge, this is the first prospective study aimed at comparing culture methods in routine use in UK clinical laboratories for the diagnosis of PJI.     

Sonication of explanted prosthetic components in bags for diagnosis of prosthetic joint infection is associated with risk of contamination

Explanted orthopedic implants from 54 patients with aseptic failure and 24 patients with prosthetic knee or hip infection were sonicated in polyethylene bags. The sensitivities of periprosthetic tissue and sonicate fluid cultures for the diagnosis of prosthetic joint infection were 54% and 75%, whereas the specificities were 98% and 87%, respectively. Sonication in bags improved bacterial recovery from the surface of orthopedic implants; however, it lacked specificity, due to bag leakage.     

Reactivation of coccidioidomycosis: a prosthetic joint infection in Spain

A resident of Spain was found to have a prosthetic knee infection due to coccidioidomycosis. He had a history of having pneumonia which resolved while living in an area of California endemic for Coccidioides in 1957–1961. The patient left California in 1961 returned to Spain and never left Spain thereafter. In 2006, a total knee replacement was done. In 2013, a prosthetic knee infection was documented due to coccidioidomycosis. By molecular DNA analysis, Coccidioides immitis was identified from the knee tissue, a species most commonly found in California. This represents reactivation of a Coccidioides infection 56 years after leaving the endemic area.     

icaA is not a useful diagnostic marker for prosthetic joint infection

A collection of 99 staphylococcal isolates associated with prosthetic joint infection and 23 coagulase-negative staphylococci isolated from noninfected arthroplasty-associated specimens were screened in order to determine whether the presence of icaA could be used to distinguish between pathogens and nonpathogens. All Staphylococcus aureus prosthetic joint infection isolates (n = 55) were icaA positive. A total of 46% (20 out of 44) of coagulase-negative staphylococcal prosthetic joint infection isolates were icaA positive, and 30% (7 out of 23) of arthroplasty-associated non-prosthetic joint infection-associated coagulase-negative staphylococcal isolates were icaA positive (P = 0.23). Certain coagulase-negative Staphylococcus species appeared more likely to be isolated as either arthroplasty-associated non-prosthetic joint infection-associated isolates (e.g., Staphylococcus warneri and Staphylococcus hominis) or pathogens (e.g., Staphylococcus lugdunensis). The presence of icaA in a coagulase-negative staphylococcal isolate associated with an arthroplasty is not a useful diagnostic indicator of pathogenicity.     

Patient-reported outcomes after above-knee amputation for prosthetic joint infection

BackgroundProsthetic joint infection (PJI) is a challenging complication after total knee arthroplasty (TKA). Above-knee amputation (AKA) is a salvage procedure that may be performed after revision TKAs fail to eradicate PJI. Few studies have investigated patient-reported outcomes. This study investigates patient-reported functional outcomes and overall satisfaction in a cohort of patients who underwent AKA for PJI.MethodsWe performed a retrospective study of all patients who underwent AKA for PJI from 2002 to 2015 at a tertiary academic institution in the rural northeastern United States, along with prospective phone interviews. Functional outcomes and overall satisfaction were adapted from the Above-The-Knee Amputation Functional Ability Questionnaire. Additional variables included age, sex, American Society of Anesthesiologists (ASA) Score, and mortality.ResultsForty-four patients were included in the study. Eighteen patients died prior to study initiation, with a mean time of 948 days (2.6 years) between AKA and death. The 5-year mortality rate was 50%. Among the 14 patients who completed the survey, 12 (86%) were fit for prosthesis following AKA. Of these, 10 (71%) required the use of an assistive device and one (seven percent) reported being functionally independent with their prosthesis. Five (36%) required further surgery after their AKA. Twelve (86%) stated that they were satisfied with their AKA and 5 (42%) would have done it sooner if offered.ConclusionsPatients who underwent AKA for PJI reported a low level of independence and ability to ambulate with a high mortality rate. However, most were satisfied with their AKA and would choose it again.     

Evaluation of two tuberculosis PCR assays for routine use in a clinical setting of low population and low tuberculosis prevalence

Today, there are numerous different molecular diagnostic assays for the detection of tuberculosis (TB), allowing the optimization of rapid detection of TB according to the clinical need. In this study, two high‐throughput TB PCR assays with combined antimicrobial resistance detection, Anyplex? II MTB/MDR (Seegene) and RealTime MTB + RealTime MTB RIF/INH Resistance (Abbott Molecular), were evaluated for routine use in a clinical setting of low population and low TB prevalence in Finland. The RealTime MTB assay was 100% concordant (22/22 positive, n = 169) with the reference methods (culture and Xpert MTB/RIF PCR assay, Cepheid). However, with a limitation of four separate PCR cycles per kit, the routine use in a low TB‐prevalence setting would easily lead to wasting most of the RIF/INH Resistance reagents. The Anyplex? II MTB/MDR assay usability was more adaptive to suit the clinical setting but the assay sensitivity was considerably lower (86%, 19/22 positive, n = 76) being closer to the sensitivity of smear microscopy. The findings of this study suggest that the evaluated high‐throughput MTB/MDR assays are evidently suboptimal for routine use in a low population, low TB‐prevalence setting. In addition, neither of the two assays covers non‐tuberculous mycobacteria and could therefore not fully replace acid‐fast staining as the initial screening method.     

Rapid diagnosis of influenza infection in older adults: influence on clinical care in a routine clinical setting.

BACKGROUND: Laboratory diagnosis of influenza has previously relied on viral isolation in culture. Rapid antigen tests (RATs) are now available but few studies have examined their use in older adults under routine clinical conditions. OBJECTIVES: To determine the utility of the RAT in older adults presenting to a large medical center and how test results impacted clinical care. STUDY DESIGN: Retrospective chart review of patients tested for influenza during the 2003--2004 and 2004--2005 influenza seasons. Clinical data were correlated with the results of laboratory testing. RESULTS: Eighty-four adults tested positive for influenza. Adding the results of the RAT to symptom complexes predictive of influenza significantly enhanced the ability to diagnose influenza in the acute setting. The positive predictive value of fever plus cough increased from 32% to 92% with a positive RAT. The RAT also directed appropriate antiviral therapy. 20/22 (91%) patients with a positive RAT and symptoms < or =48 h received antiviral treatment compared to only 1/12 (8%) patients with a negative RAT and a positive culture. CONCLUSIONS: Under routine clinical conditions rapid influenza testing enhances the ability to quickly diagnose influenza and can be used to guide early treatment decisions in older adults.     

Role of universal 16S rRNA gene PCR and sequencing in diagnosis of prosthetic joint infection

The etiological diagnosis of prosthetic joint infection (PJI) requires the isolation of microorganisms from periprosthetic samples. Microbiological cultures often yield false-positive and false-negative results. 16S rRNA gene PCR combined with sequencing (16SPCR) has proven useful for diagnosing various infections. We performed a prospective study to compare the utility of this approach with that of culture to diagnose PJI using intraoperative periprosthetic samples. We analyzed 176 samples from 40 patients with PJI and 321 samples from 82 noninfected patients using conventional culture and 16SPCR. Three statistical studies were undertaken following a previously validated mathematical model: sample-to-sample analysis, calculation of the number of samples to be studied, and calculation of the number of positive samples necessary to diagnose PJI. When only the number of positive samples is taken into consideration, a 16SPCR-positive result in one sample has good specificity and positive predictive value for PJI (specificity, 96.3%; positive predictive value, 91.7%; and likelihood ratio [LR], 22), while 3 positive cultures with the same microorganism are necessary to achieve similar specificity. The best combination of results for 16SPCR was observed when 5 samples were studied and the same microorganism was detected in 2 of them (sensitivity, 94%; specificity, 100%; and LR, 69.62). The results for 5 samples with 2 positive cultures were 96% and 82%, respectively, and the likelihood ratio was 1.06. 16SPCR is more specific and has a better positive predictive value than culture for diagnosis of PJI. A positive 16SPCR result is largely suggestive of PJI, even when few samples are analyzed; however, culture is generally more sensitive.     

How to manage treatment failure in prosthetic joint infection

BackgroundManagement 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.AimsThis article describes the approach to prosthetic joint infections in the setting of treatment failure.SourcesNarrative 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.ContentThe 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.ImplicationsProsthetic 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.     

Technetium-99m-labeled annexin V imaging for detecting prosthetic joint infection in a rabbit model

Accurate and timely diagnosis of prosthetic joint infection is essential to initiate early treatment and achieve a favorable outcome.In this study,we used a rabbit model to assess the feasibility of technetium-99m-labeled annexin V for detecting prosthetic joint infection.Right knee arthroplasty was performed on 24 New Zealand rabbits.After surgery,methicillin-susceptible Staphylococcus aureus was intra-articularly injected to create a model of prosthetic joint infection(the infected group,n = 12).Rabbits in the control group were injected with sterile saline(n=12).Seven and 21 days after surgery,technetium-99m-labeled annexin V imaging was performed in 6 rabbits of each group.Images were acquired 1 and 4 hours after injection of technetium-99 mlabeled annexin V(150 MBq).The operated-to-normal-knee activity ratios were calculated for quantitative analysis.Seven days after surgery,increased technetium-99m-labeled annexin V uptake was observed in all cases.However,at 21 days a notable decrease was found in the control group,but not in the infected group.The operated-to-normal-knee activity ratios of the infected group were 1.84 ± 0.29 in the early phase and 2.19 ±0.34 in the delay phase,both of which were significantly higher than those of the control group(P=0.03 and P=0.02).The receiver operator characteristic curve analysis showed that the operated-to-normal-knee activity ratios of the delay phase at 21 days was the best indicator,with an accuracy of 80%.In conclusion,technetium-99m-labeled annexin V imaging could effectively distinguish an infected prosthetic joint from an uninfected prosthetic joint in a rabbit model.     

Diagnosis of prosthetic joint infection by beadmill processing of a periprosthetic specimen

We report a microbiological process for the documentation of prosthetic joint infection (PJI). Intraoperative periprosthetic tissue samples from 92 consecutive patients undergoing revision surgery for PJI were submitted to mechanized beadmill processing: specimens were aseptically collected in polypropylene vials, filled with sterile water and glass beads and submitted to mechanized agitation with a beadmill. The documentation rate of PJI following culture on solid and liquid media was 83.7% and the contamination rate 8.7%. Final documentation was obtained after overnight culture for 51.9% of cases and with 7 days of broth culture for all documented cases.     

Immunofluorescence for routine diagnosis of respiratory syncytial virus infection

A comparison of immunofluorescent tests for the diagnosis of respiratory syncytial (RS) virus infections was carried out on 42 hospitalized cases of respiratory infection in childhood. Respiratory syncytial virus was detected in 22 (52%) cases, the most sensitive method of detection being by indirect immunofluorescence of Bristol HeLa tissue cultures inoculated with nasopharyngeal aspirates. The highest detection rate was in bronchiolitis cases (92%). Detection of antibody rises in paired sera, eight days apart, confirmed RS virus infection in 13 of 16 cases, the most sensitive test being detection of a specific rise in IgG antibody by indirect immunofluorescence. A serodiagnosis was made in all 10 non-bronchiolitis cases. Recommendations are made for the application ofimmunofluorescence to routine diagnosis of RS virus infection.     

Prolonged suppressive antibiotic therapy for prosthetic joint infection in the elderly: a national multicentre cohort study

During prosthetic joint infection (PJI), optimal surgical management with exchange of the device is sometimes impossible, especially in the elderly population. Thus, prolonged suppressive antibiotic therapy (PSAT) is the only option to prevent acute sepsis, but little is known about this strategy. We aimed to describe the characteristics, outcome and tolerance of PSAT in elderly patients with PJI. We performed a national cross-sectional cohort study of patients >75 years old and treated with PSAT for PJI. We evaluated the occurrence of events, which were defined as: (i) local or systemic progression of the infection (failure), (ii) death and (iii) discontinuation or switch of PSAT. A total of 136 patients were included, with a median age of 83 years [interquartile range (IQR) 81–88]. The predominant pathogen involved was Staphylococcus (62.1%) (Staphylococcus aureus in 41.7%). A single antimicrobial drug was prescribed in 96 cases (70.6%). There were 46 (33.8%) patients with an event: 25 (18%) with an adverse drug reaction leading to definitive discontinuation or switch of PSAT, 8 (5.9%) with progression of sepsis and 13 died (9.6%). Among patients under follow-up, the survival rate without an event at 2 years was 61% [95% confidence interval (CI): 51;74]. In the multivariate Cox analysis, patients with higher World Health Organization (WHO) score had an increased risk of an event [hazard ratio (HR) = 1.5, p = 0.014], whereas patients treated with beta-lactams are associated with less risk of events occurring (HR = 0.5, p = 0.048). In our cohort, PSAT could be an effective and safe option for PJI in the elderly.     

Cost analysis of debridement and retention for management of prosthetic joint infection

Prosthetic joint infection remains one of the most devastating complications of arthroplasty. Debridement and retention of the prosthesis is an attractive management option in carefully selected patients. Despite this, there are no data investigating the cost of this management modality for prosthetic joint infections. The aim of this case–control study was to calculate the cost associated with debridement and retention for management of prosthetic joint infection compared with primary joint replacement surgery without prosthetic joint infection. From 1 January 2008 to 30 June 2010, there were 21 prosthetic joint infections matched to 42 control patients. Controls were matched to cases according to the arthroplasty site, age and sex. Cases had a greater number of unplanned readmissions (100% vs. 7.1%; p <0.001), more additional surgery (3.3 vs. 0.07; p <0.001) and longer total bed days (31.6 vs. 7.9 days; p <0.001). In addition they had more inpatient, outpatient and emergency department visits (p <0.001, respectively). For patients with prosthetic joint infection the total cost, including index operation and costs of management of the prosthetic joint infection, was 3.1 times the cost of primary arthoplasty; the mean cost for cases was Australian dollars (AUD) $69 414 (±29 869) compared with $22 085 (±8147) (p <0.001). The demand for arthroplasty continues to grow and with that, the number of prosthetic joint infections will also increase, placing significant burden on the health system. Our study adds significantly to the growing body of evidence highlighting the substantial costs associated with prosthetic joint infection.     

The use of procalcitonin in the diagnosis of bone and joint infection: a systemic review and meta-analysis

Only a few studies have investigated the use of PCT in the diagnosis of bone and joint infection, and these studies have had relatively small sample sizes. We performed a systematic review and meta-analysis of the diagnostic performance of serum procalcitonin (PCT) in the identification of osteomyelitis and septic arthritis in patients who present with fever and orthopedic symptoms. EMBASE, MEDLINE, and Cochrane databases and the reference lists of relevant articles were searched, with no language restrictions, through February 2012. All original studies that reported the use of serum PCT alone or in comparison with other biomarkers for diagnosis of osteomyelitis and septic arthritis were included. Seven studies qualified for inclusion. These studies enrolled a total of 583 patients with suspected bone or joint infection, 131 of whom had confirmed osteomyelitis or septic arthritis. Analysis of the PCT data indicated a bivariate pooled sensitivity of 0.67 (95 % CI: 0.37–0.88), specificity of 0.90 (95 % CI: 0.78–0.96), a positive likelihood ratio (LR+) of 6.48 (95 % CI: 2.28–14.6), and a negative likelihood ratio (LR?) of 0.37 (95 % CI: 0.16–0.84). Use of a lower PCT cut-off value (0.2–0.3 ng/mL) improved the LR + to 6.66 and the LR? to 0.15. Analysis of the three studies that also measured serum C-reactive protein (CRP) indicated that CRP had an LR + of 1.39 (95 % CI: 1.17–1.65) and an LR? of 0.40 (95 % CI: 0.12–1.36). Our results indicate that PCT may be more suitable as an aid for rule-in diagnosis rather than for exclusion of septic arthritis or osteomyelitis and that use of a lower cut-off value for serum PCT may improve its diagnostic performance.