Aim. It is unclear if the prevalence of resistance organisms causing (PJI) in total hip/knee arthroplasty is different among North/South American and European countries. Therefore, we sought to compare causative organisms, rates of resistant organisms, and polymicrobial infections in hospitals in North/South America, and Europe. Method. We performed a retrospective study of 654 periprosthetic hip (n=361) and knee (n=293) infections (January 2006-October 2019) identified at two facilities in the United States (US) (n=159), and single institutions located in Argentina (n=99), Uruguay (n=130), United Kingdom (UK) (n=103), Germany (n=59), and Russia (n=104). The analyses were performed for the entire cohort, knees, and hips. Alpha was set at 0.05. Results. Overall, the most frequent organisms identified were Staphylococcus aureus (24.8%) and Staphylococcus epidermidis (21.7%). The incidence of organisms resistant to at least one antibiotic was 58%. In this regard, there was a significant difference between hips (62.3%) and knees (52.6%) (p=0.014). The rates of resistant organisms among countries were significantly different: 37.7% (US), 66.7% (Argentina), 71.5% (Uruguay), 40.8% (UK), 62.7% (Germany), and 77.9% (Russia) (p<0.001). The overall incidence of polymicrobial infections was 9.3% and the rates across nations were: 9.4% in the US, 11.1% (Argentina), 4.6% (Uruguay), 4.9% (UK), 11.9% (Germany), and 16.3% (Russia) (p=0.026). In an exclusive analysis of the hips, the incidence of resistant organisms was 62.3% while polymicrobial infections accounted for 10.5% of all cultures. The rates of resistant organisms in each country were: 42.9% in the US, 59.2% (Argentina), 78.5% (Uruguay), 41.3% (UK), 63.9% (Germany), and 80.0% in Russia (p<0.001). The incidences of polymicrobial infections were: 9.1% in the US, 6.1% (Argentina), 6.5% (Uruguay), 6.5% (UK), 16.7% (Germany), and 21.7% in Russia (p=0.024). Regarding the knees, the incidence of resistant organisms was 52.6% while the frequency of polymicrobial infections was 7.8%. The rates of resistant organisms in each country were: 32.9% in the US, 74% (Argentina), 54.1% (Uruguay), 40.4% (UK), 60.9% (Germany), and 75% in Russia (p<0.001). The frequencies of polymicrobial infections were: 9.8% in the US, 16% (Argentina), 0% (Uruguay), 3.5% (UK), 4.3% (Germany), and 9.1% in Russia (p=0.072). Conclusions. Staphylococcus aureus and epidermidis accounted for almost 50% of all infections. The US and the UK had the lowest incidence of resistant organisms while Germany and Russia had the highest. The UK and Uruguay had the lowest rates of polymicrobial infections. These differences between countries and continents may affect comparative studies that evaluate treatments for PJI

Aim. It is traditionally stated that around 80% of all periprosthetic joint infections (PJI) are caused by well-known gram-positive organisms such as Staphylococcus aureus. With the advances in diagnostic modalities and improved abilities to isolate infective organisms, we believe the organism profile causing PJI has changed over time and includes numerous other organisms that were either not recognized as pathogens and/or considered as contaminants. Method. We retrospectively reviewed the medical records of 1,363 patients with confirmed PJI (559 THA and 804 TKA) who received treatment at our institution between 2000 and 2019. Pertinent data related to demographics, microbiological findings, and outcome of treatment were collected. Organisms were differentiated using culture or confirmed by Matrix-Assisted Laser Desorption Ionization-time of flight (MALDI-tof) mass spectrometry. Statistical analysis included logistic regressions. Results. There was a total of 26 different species of organisms that resulted in PJI in our cohort. The rate of PJI caused by slow growing organisms, that are catalase negative, such as Streptococcal viridans (OR 1.244; 95% CI 1.036–1.494), Streptococcus agalactiae (OR 1.513; 95% CI 1.207–1.898), and Staphylococcus epidermidis (OR 1.321; 95% CI 1.191–1.466) has been increasing over time. In contrast, the incidence of PJI caused by coagulase-negative Staphylococcus (OR 0.954; 95% CI 0.927–0.981); resistant species (OR 0.962, 95% CI 0.931–0.995), and Gram-positive species (OR 0.94, 95% CI 0.914–0.966) decreased over time. Notably, there was a higher prevalence of Streptococcal PJI (OR 0.551, 95% CI 0.374–0.812) and culture-negative PJI (OR 0.652, 95% CI 0.478–0.890) seen in knees versus hips. The rate of culture negative PJI also increased from 20% in 2000 to 28% in 2019. In the latter years of the study, very unusual list of organisms causing PJI were also identified. Conclusions. This study reveals that the list of organisms causing PJI has expanded in recent years. The study also finds that some the slow growing organisms that were previously believed to be “contaminants” can and do cause PJI in a considerable number of patients. The number of culture negative cases of PJI has also increased at our institution over the years. There are a number of explanations for the latter finding, perhaps with the most important reason being liberal use of antibiotics that interferes with isolation of the infective organism

Aim. To determine mortality and outcomes of patients diagnosed with fracture-related infections (FRIs). Method. FRI patients treated at a trauma centre between 2001 and 2020 were analysed. The primary outcome was 1-year mortality; mortality associations with FRI organism, depth of involvement, and temporality were investigated with multivariable survival analysis. Healthcare-associated and serological outcomes were reported as secondary outcomes. Results. 311 FRIs with mean age of 67.0 and median Charlson comorbidity index of 0 were analysed. Methicillin-sensitive Staphylococcus aureus (MSSA) (29.9%) was the most frequently implicated organism. The majority of FRIs were deep infections (62.7%). FRIs were diagnosed at a median of 40 (IQR 15–200) days post index surgery. The mean follow-up was 5.9 years. One-year mortality amounted to 17.7%. MSSA FRIs were associated with better survival (adj HR 0.34, 95%CI 0.15–0.76, p=0.008). There was no difference in survivorship between deep or superficial FRI (adj HR 0.86, 95%CI 0.62–1.19, p=0.353) or in relation to onset time (adj HR 1.0, 95%CI 0.99–1.00, p=0.943). Implant removal or debridement alone was performed in 61.7% and 17% respectively. Antibiotics was prescribed for 53 (IQR 23–110) days, and patients were hospitalised for 39 (IQR 19–78) days. CRP and ESR normalised in 70.3% (median 46 days) and 53.8% (median 86 days) patients respectively. Conclusions. Fracture-related infections are associated with significant mortality and morbidity regardless of depth and temporality. Non-MSSA FRIs are associated with inferior survival

Perioperative antibiotic prophylaxis remains one of the most important strategies for prevention of periprosthetic joint infection (PJI) with current guideline recommending a first or second generation cephalosporin. Penicillin (PCN) allergy is often reported by patients, which often results in avoidance of administration of cephalosporins due to fear of cross-reactivity. Alternative medications, such as vancomyin, are often used despite reduced antimicrobial coverage. The purpose of this study was to determine if PCN allergic patients who received vancomycin alone prior to elective primary total joint arthroplasty were at increased risk of developing a subsequent PJI. A retrospective review of 7,602 primary total joint arthroplasties (TJAs) performed between 2005 and 2013 in two institutions were identified using a prospective institutional database. Patient reported PCN or cephalosporin allergy was electronically queried from the anesthesia note. Patients who recieved multiple prophylactic antibiotics, or had unavailable perioperative antibiotic information, or those who received medication other than cefazolin and vancomycin were excluded. PJI was determined using a cross-match with an institutional PJI database constructed from International Classification of Diseases (ICD)-9 codes. Logistic regression analysis was then performed to evaluate the risk of subsequent PJI. The rate of PJI was 1.4% (32/2296) in patients with a reported PCN allergy that received vancomycin alone versus 1.1% (59/5306) in non-PCN allergic patients that received cefazolin alone. The multivariate analysis, with the given sample size, did not detect a statistically significant increased risk of PJI when vancomycin was administered alone (adjusted odds ratio: 1.23, 95% CI 0.6–3.1, p=0.35). While there was no significant differences in the organism profile between PJIs in both groups, the rate of PJI caused by resistant organisms was higher in patients who received vancomycin alone (11.9%, 7/59) compared to those who received cefazolin (3.1%, 1/32). While administration of perioperative prophylactic vancomycin alone during elective primary arthroplasty does not seem to result in a higher rate of subsequent PJI, patients who received vancomycin alone and developed a PJI were more likely to develop an infection with an antibiotic resistant organism. Future studies are needed to determine the most appropriate prophylactic antibiotic for patients who undergo elective arthroplasty and report PCN allergy

Objective. Pyogenic spinal infection (PSI) is an increasingly common presentation to spinal units in the UK. Its investigation and diagnosis is often delayed. The purpose of this study was to determine the prognostic significance of the inflammatory marker levels on admission on achieving a positive microbiological diagnosis in patients with PSI. Study design. Retrospective case series review of all patients presenting with PSI to our unit. Subjects. Clinical data were collected on 96 consecutive patients diagnosed with a PSI over a 7-year period. Patient < 18 years at time of presentation or who had previous spinal surgery were excluded. Outcome Measures. Positive blood and/or tissue culture, and requirement for surgery. Continuous data were compared using the Wilcoxon rank-sum test∗∗ and logistical regression remodelling was assessed using the Spearman correlation∗. Categorical data was analysed using Fisher's exact test. ∗∗∗. Results. The C-reactive protein was statistically significant for; duration of preceding symptoms (p=0.0003)∗, isolation of a causative organism (p< 0.0001)∗∗, positive biopsy culture (p=0.0016)∗∗ and requirement for surgery (p=0.031)∗∗. The White Blood Cell (WBC) count was statistically significant for; duration of preceding symptoms (p< 0.0001)∗, isolation of a causative organism (p = 0.0003)∗∗, positive biopsy culture (p=0.0023)∗∗. The majority of patients who had a positive tissue culture had a positive blood culture (p< 0.0001)∗∗∗. Conclusion. The inflammatory marker levels on admission are a useful prognostic marker for isolating a causative organism in patients with PSI and help guide treating surgeons to whether proceeding to biopsy is likely to be a helpful investigation. Tissue biopsy in patients with PSI is only marginally superior to blood culture alone

Aims. Excision of chronic osteomyelitic bone creates a dead space which must be managed to avoid early recurrence of infection. Systemic antibiotics cannot penetrate this space in high concentrations, so local treatment has become an attractive adjunct to surgery. The aim of this study was to present the mid- to long-term results of local treatment with gentamicin in a bioabsorbable ceramic carrier. Methods. A prospective series of 100 patients with Cierny-Mader Types III and IV chronic ostemyelitis, affecting 105 bones, were treated with a single-stage procedure including debridement, deep tissue sampling, local and systemic antibiotics, stabilization, and immediate skin closure. Chronic osteomyelitis was confirmed using strict diagnostic criteria. The mean follow-up was 6.05 years (4.2 to 8.4). Results. At final follow-up, six patients (six bones) had recurrent infection; thus 94% were infection-free. Three infections recurred in the first year, two in the second year, and one 4.5 years postoperatively. Recurrence was not significantly related to the physiological class of the patient (1/20 Class A (5%) vs 5/80 Class B (6.25%); p = 0.833), nor was it significantly related to the aetiology of the infection, the organisms which were cultured or the presence of nonunion before surgery (1/10 with nonunion (10%) vs 5/90 without nonunion (5.6%); p = 0.570). Organisms with intermediate or high-grade resistance to gentamicin were significantly more likely in polymicrobial infections (9/21; 42.8%) compared with monobacterial osteomyelitis (7/79 (8.9%); p < 0.001). However, recurrence was not significantly more frequent when a resistant organism was present (1/16 for resistant cases (6.25%) vs 5/84 in those with a microbiologically sensitive infection (5.95%); p = 0.958). Conclusion. We found that a single-stage protocol, including the use of a high-delivery local antibiotic ceramic carrier, was effective over a period of several years. The method can be used in a wide range of patients, including those with significant comorbidities and an infected nonunion. Cite this article: Bone Joint J 2022;104-B(9):1095–1100

Osteoarticular infections (OAI) are a common cause of morbidity in children, and as opposed to adults is usually caused by haematogenous spread. The bacteriology of OAI in children is not well described in the South African context, therefore this study was designed to determine the bacteriology of OAI in our population. All patients that underwent surgery for the treatment of OAI over a 3-year period were identified and those with positive cultures where organisms were identified from tissue, pus, fluid or blood were included. Duplicate cultures from the same patient were excluded if the organism and antibiotic susceptibility profile was the same. Patients were categorised according to age and class of infection (Septic arthritis, acute osteomyelitis, fracture related infection, post-operative sepsis and chronic osteomyelitis) and organisms were stratified according to these categories. We identified 132 organisms from 123 samples collected from 86 patients. Most cultured organisms were from children older than 3-years with acute haematogenous septic arthritis, osteomyelitis, or both. Methicillin sensitive Staphylococcus aureus accounted for 56% (74/132) of organisms cultured. There were no cases of MRSA. The Enterobacterales accounted for 17% (22/132) of organisms cultured, mostly in the fracture related and post-operative infection groups. Of these, 6 each were extended spectrum B-lactamase producers and AmpC producers. There were no carbapenemase producing Enterobacterales. Kingella kingae was not isolated in any patient. Methicillin sensitive S. aureus is the most common infecting organism in paediatric OAI and an anti-staphylococcal penicillin such as cloxacillin or flucloxacillin is the most appropriate empiric treatment for haematogenous OAI in our environment. In fracture related or post-operative infections, Enterobacterales were more frequently cultured, and treatment should be guided by culture and susceptibility results

Aims. Bone and joint infections cause significant morbidity, often requiring combination medical and surgical treatment. The presence of foreign material reduces the number of organisms required to cause an infection. The aim of this study was to assess whether there was a difference in the species of organism identified on culture in osteomyelitis compared to prosthetic joint infection. Method. This was a retrospective observational cohort study of patients that had surgical intervention for prosthetic joint infection or osteomyelitis with positive microbial culture between 2019 and 2022. Data including patient demographics, site of injury, BACH score for osteomyelitis and JS-BACH score for prosthetic joint infection, organism classification and antibiotic resistance to vancomycin and gentamicin were extracted from the medical record. Logistic and multiple regressions were used to adjust for potential confounding variables. Results. A total of 445 patients were included in the study; 267 patients with osteomyelitis or fracture-related infection and 177 patients with prosthetic joint infection. The patients with prosthetic joint infection were older (Mean age 70 for PJI; IQR 60-77 vs 56 for OM/FRI; IQR 39-64), more likely to be female (55.6% vs 26.2%) and had a higher BMI and ASA compared to those with osteomyelitis. Symptom duration tended to be longer in osteomyelitis/FRI (p<0.001). Staphylococcus aureus was the most common pathogen isolated in both osteomyelitis (155/267 (58.1%)) and prosthetic joint infection (85/177 (48.9%), followed by other Gram negative pathogens with 77/267 (28.8%) in osteomyelitis and 48/177 (27.1%) in prosthetic joint infection. On multivariate analysis, there was no difference between the rate of Staphylococcus aureus infection between the two groups. The rate of polymicrobial infection was higher in patients with osteomyelitis (92/267 (34.5%)) compared to prosthetic joint infection (38/177 (23.7%), however after adjustment for confounders there was no difference, p = 0.842. There was no difference in the presence of gentamicin resistant organisms or vancomycin resistant Gram positive organisms in osteomyelitis compared to prosthetic joint infection. Conclusion. Causative pathogens are similar in these two common forms of bone and joint infection. There was no significant difference in the identification, presence of polymicrobial infection or gentamicin and vancomycin resistance in organisms isolated in osteomyelitis compared to prosthetic joint infection. This may have implications for empiric antibiotic choice and local antibiotic therapy in the management of bone and joint infection

Aim. We reviewed a cohort of individuals with recurrent orthopaedic infection to describe the relative rates of microbial persistence vs re-infection at recurrence surgery. Method. A cohort of 125 individuals with recurrent infection (prosthetic joint infection, fracture-related infection and osteomyelitis) from two centres in the UK between 2007 and 2021. Electronic patient records were reviewed to identify culture results from surgical samples at index surgery and the next operation for recurrent infection. Antibiotic sensitivity results were recorded as sensitive, intermediate or resistant according to contemporary sensitivity testing guidelines. Results. Among patients with recurrent infection, 78/125 (62.4%) were male, with a median age 64 years (IQR 51–73y). 76 had prosthetic joint infection, and 49 had fracture related infection or osteomyelitis. Culture results at index procedure showed the most frequently isolated species were Staphylococci (Table 1). A single species was isolated in 75/125 (60%) and mixed species in 36/125 (28.8%). No organisms were cultured in 14/125 (11.2%). At re-operation 48/125 (38.4%) individuals had an organism from the same species or group as at the index operation. In 49/125 (39.2%), none of the organisms isolated at re-operation were grown at first operation. In 28/125 (22.4%), re-operative cultures yielded no growth. For each species isolated at the index procedure, the proportion with the same, different or no organisms isolated at the next procedure were reviewed (Table 1). Staphylococci (including S. aureus and coagulase-negative staphylococci) and Pseudomonas species showed the highest rate of persistence at the species level. Among coagulase-negative staphylococci, changes in antimicrobial sensitivity that make it unclear if these infections were truly persistent, or represented re-infection. Conclusions. Infection with different organisms was seen at similar rates (39.2% vs 38.4%) to persistent infection with the same species in this cohort. Staphylococcus aureus is the organism most likely to be persistently identified in recurrent infections

Introduction. A proportion of patients with hip and knee prosthetic joint infection (PJI) undergo multiple revisions with the aim of eradicating infection and improving quality of life. The aim of this study was to describe the microbiology cultured from multiply revised hip and knee replacement procedures to guide antimicrobial therapy at the time of surgery. Patients and Methods. Consecutive patients were retrospectively identified from databases at two specialist orthopaedic centres in the United Kingdom between 2011 and 2019. Patient were included who had undergone repeat revision total knee replacement (TKR) or total hip replacement (THR) for infection, following an initial failed revision for infection. Results. 106 patients were identified, of which 74 underwent revision TKR and 32 underwent revision THR. Mean age at first revision was 67 years (SD 10). Charlson Comorbidity Index was <2 for 31 patients, 3–4 for 57 patients, and >5 for 18 patients. All patients underwent >2 revisions, 73 patients received 3, 47 patients received 4, 31 patients received 5, and 21 patients received >6. After six revisions, 90% of patients cultured different organisms than the initial revision, and 53% of organisms were multi-drug resistant species. The most frequent organisms at each revision were coagulase negative Staphylococcus (36%) and Staphylococcus aureus (19%). Fungus was cultured from 3% of revisions and 21% of infections were polymicrobial. Conclusion. Patients undergoing multiple revisions for PJI are highly likely to experience a change in organisms and sensitivities with each subsequent revision. It is important to administer empirical antibiotics at each subsequent revision, appreciating known drug resistance from previous cultures. Our results do not support routine use of empirical antifungals

Prosthetic joint infection (PJI) remains one of the most challenging complications to manage following total joint arthroplasty (TJA). There is a paucity of published data on the management of PJI in smaller, rural hospital settings. In this study, we investigate [1] the success rate of surgical management for PJI following TJA and [2] the microbiology of infecting organisms in this unique geographical environment. We performed a retrospective single-centre study at a rural hospital (Southland Hospital, Invercargill, New Zealand) over a 3-year period (2019 to 2022). All patients presenting with a first episode of PJI fulfilling Musculoskeletal Infection Society criteria after hip or knee arthroplasty were included. All patients had a minimum follow up of 6 months. Treatment success was defined eradication of infection. Twenty-one cases (14 hips and 7 knees) were identified. These were managed with Debridement, antibiotics, and implant retention (DAIR) procedure (n=14, 67%), single-stage revision (n=6, 29%), or long-term suppressive antibiotics (n=1, 4%). Of the DAIR patients, infection recurred in 50% and underwent subsequent revision. Of the single-stage revision patients, 17% failed and underwent subsequent revision. The overall success rate was 90%. Methicillin-sensitive Staphylococcus aureus (MSSA) was the most isolated pathogen (57%,) with no methicillin-resistance Staphylococcus aureus (MRSA) identified. Overall, 90% of infecting organisms were cefazolin sensitive. These results suggest that management of PJI is a safe and viable treatment option when performed in a rural hospital setting, with comparable treatment success rates to urban centres. The incidence of MRSA is low in this setting. Rates of antibiotic resistance were relatively low and most organisms were sensitive to cefazolin, the routine antibiotic used in prophylaxis

Aim. Surgical management of PJI remains challenging with patients failing treatment despite the best efforts. An important question is whether these later failures reflect reinfection or the persistence of infection. Proponents of reinfection believe hosts are vulnerable to developing infection and new organisms emerge. The alternative hypothesis is that later failure is a result of an organism that was present in the joint but was not picked up by initial culture or was not a pathogen initially but became so under antibiotic pressure. This multicenter study explores the above dilemma. Utilizing next-generation sequencing (NGS), we hypothesize that failures after two-stage exchange arthroplasty can be caused by an organism that was present at the time of initial surgery but not isolated by culture. Method. This prospective study involving 15 institutions collected samples from 635 revision total hip(n=310) and knee(n=325) arthroplasties. Synovial fluid, tissue and swabs were obtained intraoperatively for NGS analysis. Patients were classified per 2018 Consensus definition of PJI. Treatment failure was defined as reoperation for infection that yielded positive cultures, during minimum 1-year follow-up. Concordance of the infecting pathogen cultured at failure with NGS analysis at initial revision was determined. Results. Among the total cohort, 203 revisions were considered infected and 432 were aseptic (based on ICM-criteria). Of the infected cases, 157 were NGS-positive and 46 NGS-negative. Twenty-nine ICM-positive patients (29/157;18.5%) failed by reoperation with an organism confirmed on culture. In 23 of these (23/29;79.3%), the organism at failure was present on NGS at initial revision. The remaining 6 cases detected discordant organisms between initial NGS and culture at failure. Of the 432 ICM-negative patients, NGS identified microbes in 48.1% (208/432) of “aseptic” revisions, and 17 of these failed. Thirteen of the 17 failures (76.5%) were due to an organism previously detected by NGS at initial revision. Conclusion. Our collaborative findings suggest that most failures (79.3%) by infection recurrence could be attributed to an organism previously detected by NGS at index revision surgery

Aim. An instrumented blood culture system automatically flags when growth within the culture medium has been detected (‘work in progress’), and subsequently when the organism has been identified. We explore using this data to switch patients to oral therapy within 72 hours post-surgery, reducing costs and improving antimicrobial stewardship. Method. This retrospective review focused on clinically significant culture-positive bone and joint infections over a 5-month period in 2022. Two cohorts were defined as either having positive intraoperative microbiology at <72 hours or at ≥72 hours. Results. 150 patients were included. 133/150(88%) exhibited microbial growth <72hours. Of these, 98/133(74%) had all organisms identified <72-hours, and 34/133(26%) had additional organisms ≥72 hours. 19/151(12%) patients had their first positive cultures ≥72hrs from sampling. The most common isolates identified within 72 hours were S. aureus(30%), Enterobacteriaceae (26%), and Coagulase-negative Staphylococcus (CoNS)(19%). If no growth was observed by 48 hours, there was a 69.6% probability that subsequent growth wouldn't occur; this probability increases to 81.9% by 72 hours, 88.7% by 96 hours, 91.0% by 120 hours, and 95.0% by 144 hours (see figure 1). The most common isolates identified ≥72 hours were CoNS(28%), Cutibacterium acnes(16%) and S. aureus(12%). Assessing oral antibiotic regimes for isolates identified after 72 hours demonstrated that linezolid would cover isolates from 96% of patients, tetracyclines 92% of patients, clindamycin 85% of patients, and ciprofloxacin and rifampicin would cover 80% of patients. Vancomycin and meropenem, our standard empirical therapy, gave the best cover at 96% of patients. Conclusions. This study suggests there is sufficient microbiological information at 72 hours for most patients to allow transition to a targeted regimen. If there has been no detection of growth when using an instrumented blood culture system by 72 hours, it is likely that there will be no growth. For any tables or figures, please contact the authors directly

Aim. There are no definitive criteria for the definition of osteomyelitis in the hand and wrist and published case series are small. It remains a relatively uncommon, but difficult to treat problem. We present a series of 30 cases from 2016 to 2021 from a tertiary referral centre. We propose that the principles of thorough surgical debridement, dead space management, skeletal stabilisation and culture driven antibiotic therapy are the key to management of osteomyelitis in the hand and wrist. In addition, we show how these basic principles can be used for both functional and aesthetic impact for the wrist and digits with illustrated cases. Methods. We conducted a retrospective chart review over a 6 year period and recorded the site of the infection, the soft tissue and bony management, whether antibiotic eluting bone filler was used, the isolated bacterial species, the number of surgical procedures undertaken to treat the infection and the success rate for clearing the infection. Results. 17/30 cases had pre-existing metalwork in-situ. There were 19 phalangeal/metacarpal infections and 11 carpal infections. 24 patients had native joint involvement. A drug eluting bone void filler was used in 23/30 cases in order to manage the dead space. In 7/30 cases had polymicrobial organisms isolated, 15/30 had only one organism cultured. The most common organism cultured was Staphylococcus aureus. Complete resolution of osteomyelitis or joint infection was achieved in 29/30 cases with follow up ranging from six months to six years. 2/30 cases required thorough debridement of the distal phalanx; bone void filler provided an aesthetically optimal result to improve fingertip contour whilst managing the dead space. Conclusion. Osteomyelitis of the hand and wrist is optimally managed with thorough surgical debridement, dead space management with a drug eluting bone void filler, skeletal stabilisation and culture directed antibiotic therapy. In addition, the bone void filler provides pulp support and improves the aesthetic contour of fingertips in which distal phalangeal osteomyelitis was successfully treated

Aim. Local antibiotic treatment for bone and joint infections offers direct delivery of high concentrations of antibiotics with reduced systemic exposure and favourable safety profile. However, the possibility of prolonged release of antibiotics at sub-therapeutic levels creates concern about the possible development of antimicrobial resistance. We investigated patients with recurrent bone and joint infection for evidence of antimicrobial resistance emerging from the use of local antibiotics. Method. 125 patients with recurrent infection (prosthetic joint infection, fracture related infection and osteomyelitis) in the UK between 2007 and 2021 were identified. Electronic patient records (including operative notes, pathology results and prescriptions) were reviewed to extract site of infection, date of surgery, the use of local antibiotics, culture results, empiric and definitive antibiotic therapy. All antibiotic sensitivity results were recorded as sensitive, intermediate or resistant according to contemporary guidelines (BSAC and EUCAST). Results. Local antibiotics were used in 74/125 (59.2%) of patients. Agents used were Gentamicin 53/125 (42.4%), Tobramycin 18/125 (14.4%), and vancomycin in 19/125 (15.2%). Combined gentamicin and vancomycin usage was seen in 16/125 patients (12.8%). Gentamicin non-sensitivity was common in this cohort with frequent aminoglycoside use. At index procedure, a Gentamicin non-sensitive organism was cultured in 51/125 patients (40.8%). At re-operation this proportion was lower: 40/125 (32%). There was no statistically significant difference in the rate of Gentamicin resistance at reoperation comparing patients who previously received local aminoglycosides with those who had not (21/71, 29.8% vs 19/54, 35.2% p=0.6, chi-squared test). In 48/125 (38.4%) of patients, the same species was isolated during the index and recurrence surgery. We identified 7 cases with new aminoglycoside resistance arising at the second procedure. In 2/7 – S. aureus and E. faecalis - aminoglycoside resistance was the only change in antimicrobial sensitivity. In 5/7, there were at least 2 additional changes in observed antimicrobial sensitivity. 3/74 (4%) of cases who initially received local aminoglycoside cultured organisms with aminoglycoside resistance at recurrence. 4/51 (7.8%) of those who did not receive local or systemic aminoglycoside at index surgery cultured resistant organisms (chi square 0.82; p=0.365). Conclusions. As a group, patients whose treatment for orthopaedic infection included local antibiotics did not exhibit higher rates of specific antimicrobial resistance compared with those not treated with local antibiotics. However we did identify cases where Gram positive bacteria developed aminoglycoside resistance regardless of their initial antimicrobial therapy. This should be considered in antimicrobial choice during surgery for recurrence

Most patients treated at our clinical setting present during chronic osteomyelitis stage, which is anecdotally likely to be poly-microbial. Adults with poly-microbial infection have a predilection for gram-negative bacteria and anaerobes, a scenario that hypothetically leads to a higher morbidity of poly-microbial osteomyelitis following trauma. Our study looks into the epidemiology of poly-microbial osteomyelitis treated at our Tumour and Infection unit. Retrospective study of patients treated for osteomyelitis from 2016 to 2020. Records of eligible patients were retrieved for examination. Demographics such as age, sex and race were recorded. Clinical presentation, organisms cultured, including their anti-microbial sensitivities were documented. There were 63 participants in the study. 31 (49.21%) had mono-microbial osteomyelitis with 32 (50.79%) having poly-microbial osteomyelitis. Majority of the poly-microbial patients presented with a sinus (68.75%) mostly located in the tibia (50%). Multiple mixed pathogens (both gam-positive and gram-negative) were cultured in our patients and this comprised 71.21% of the total bacteria cultured. Staphylococcus Aureus was the commonest bacteria (30%) isolated, followed by Enterococcus faecalis (12%). The commonest gram-negative bacteriae cultured was Enterococcus cloacae (10%) followed by Acinetobacter baumannii (7%). Most enterobacteriacae species were sensitive to Ertapenem and Ceftazidime. A slightly higher incidence of poly-microbial osteomyelitis was found in our study than that reported in literature. Furthermore, our study demonstrated a wide variety of organisms found in poly-microbial osteomyelitis, with a large contribution made by gram-negative anaerobic rod-shaped bacteria

Introduction. Introduction: Pin site infection is a common complication during treatment with a circular frame external fixator and increases time and support patients require from the limb reconstruction team. Wound swabs were not routinely sent by the clinical nurse specialists prior to this study, with most pin site infections treated as Staphylococcus aureus with flucloxacillin (clindamycin in penicillin allergy). The aim of this study was to ascertain whether routine sending of wound swabs in pin site infection would change antibiotic treatment. Materials & Methods. Materials and Method: Patients presenting at clinic or physiotherapy with clinical signs of pin site infection were assessed using the Maz Oxford Nuffield (MON) Pin Site Infection Grading System© (OUH, 2021). Antibiotics were commenced as per unit guidelines and swabs sent for microscopy, culture and sensitivity. Results. Results: There were forty patients treated with pin site infections. Swab results showed S. aureus in 60% (N=24), other organisms in 15% (N=6) and no growth or mixed skin organisms in 10% (N=10). Flucloxacillin was prescribed to 77.5% (n=31) of patients with the remaining 22.5% (n=9) of patients receiving clindamycin (due to allergy) or rifampicin and ciprofloxacin (due to a previous MRSA diagnosis). Antibiotic management was subsequently changed in only 5% (n=2) of patients due to one patient with a new MRSA diagnosis and one patient growing Enterobacter in three pin sites tested. Conclusions. Conclusion: This study has shown that routine swab testing of pin sites does not usually change antibiotic management but should still be used in multiple, severe or unresolving pin site infections

Aim. Mega-endoprosthesis over the last two decades have played a significant role in management of non-neoplastic cases for limb salvage for a variety of indications involving bone loss, infection, fracture and failed revision surgery. This is a retrospective case control study comparing outcomes of Mega-Endoprosthesis (MEP) in non-neoplastic cases with periprosthetic joint infections (PJI), with previous history of PJI and aseptic revision. Failure was defined as persistence/recurrence of infection, all cause revision, and antibiotic suppression during the follow up period. Secondary aims were identification of causative organisms, resistance profile and causative factors for revision surgery. Method. A total of 122 patients undergoing 133 MEPs were identified between January 2012 and December 2020. 60 procedures were categorised as group 1 (infection; 50%), 20 as group 2 (previous history of infection; 16.7%), and 53 controls (no infection; 44.2%). Mean age of the cohort was 70.97 years (37.16–94.17), with a mean follow-up of 44.5 months (0.2–179) including patients lost to follow up. Results. Overall failure rate was 71/133 53.3% (group 1 39/60 (55.56%), group 2 12/20 (60%) and controls 20/53 (37.7%)). Thirteen patients died in the first 2 years (five in group 1, one in group 2 & seven in controls). The most common postoperative infection was polymicrobial followed by Coagulase Negative Staphylococcus Species (CoNS) and Methicillin Sensitive Staphylococcus aureus (MSSA). Nineteen patients had polymicrobial PJI (Eighteen in group 1 and one in control). CoNS led to postoperative infection in Fifteen patients (six in group 1, five in group 2 and four in control group). MSSA was the pathogen in four patients (three in group-1 and one in the control group). The same organisms were responsible for recurrent infection in fourteen patients in group 1 and one patient in group 2. Limb salvage was achieved in 96.2% overall (95% group 1, 90% group 2, 100% control group). Conclusions. MEPs in the context of PJI have a significant risk of failure however they play an important role in limb salvage. Patients should be counselled appropriately prior to surgery

Aim. This study aimed to evaluate the impact of intraoperative direct sonication on the yield of traditional culture and the time to positivity (TTP) of cultures obtained for periprosthetic joint infection (PJI), thereby assessing its potential to improve diagnostic efficiency and reduce contamination risk. Method. A prospective cohort study was conducted at a tertiary care center, involving 190 patients undergoing revision surgery for PJI from August 2021 to January 2024. Patients were included based on the 2018 International Consensus Meeting definition of PJI. The study utilized a novel sonication protocol, which involved direct intraoperative sonication of the implant and tissue, followed by incubation in a BACT/ALERT 3D system. The primary outcomes measured were the number and percentage of positive culture samples, identified microorganisms, and the TTP of each culture. Statistical analysis was performed using R software, with various tests applied to assess the significance of findings. Results. The study included 510 positive cultures from 190 patients, demonstrating that sonication significantly improved the positivity rate for both tissue and prosthesis specimens (p < 0.05). The median TTP for all samples was 3.13 days, with sonicated samples showing a significantly shorter TTP compared to non-sonicated samples (p < 0.05). Specifically, the shortest median TTP was observed in prosthesis post-sonication samples. Furthermore, the study found that Gram-positive organisms had a shorter TTP than gram-negative organisms, and specific microorganisms like Staphylococcus aureus and MRSE showed the fastest TTP. The analysis also revealed higher positivity rates in chronic PJIs compared to acute PJIs for sonicated tissue samples. Conclusions. The study demonstrates that intraoperative direct sonication combined with the BACT/ALERT 3D system can significantly enhance the diagnostic yield of cultures and reduce the TTP for common PJI pathogens. This novel technique not only improves pathogen detection, facilitating the tailoring of antibiotic therapy, but also potentially reduces the risk of contamination associated with sonication. These findings suggest that direct intraoperative sonication could be a valuable addition to the current diagnostic protocols for PJI, contributing to more effective management and treatment of this complex condition. Further research is necessary to explore the clinical significance of TTP and its correlation with patient outcomes in PJI

Aims. The microbiological detection of microorganisms plays a crucial role in the diagnosis as well as in the targeted systemic and local antibiotic therapy of periprosthetic infections (PJI). Despite extensive efforts to improve the sensitivity of current culture methods, the rate of culture-negative infections is approximately 10–20% of all PJI. This study investigates an preanalytical algorithm (culture collection and direct processing in the OR) to potentially increasing culture yield in patients with PJI. Methods. Patients undergoing staged revision arthroplasty for PJI in our hospital between October 2021 and 2022 were included in this prospective pilot study. Intraoperatively twenty tissue samples were collected and distributed among 4 groups. Tissue samples were prepared according to standard without medium and in thioglycolate medium at 3 different temperatures (room temperature, 4°C, 37° for 24h before transport to microbiology) directly in the OR. The removed implants were sonicated. Cultures were investigated on days 1, 3, 7, 12, 14 for possible growth. All grown organism, the number of positive samples and the time to positivity were recorded and compared. Results. 71 patients were included (age, gender). Compared to the standard procedure the thioglycolate broth at 37°C was significantly more often culture-negative (p=0.031). No significant differences in the frequency of culture-negative samples were detected in the other groups. 8.4% (6/71) patients were culture negative in the standard culture but positive in the thioglycolate samples. In contrast, 7% (5/71) were culture negative in the thioglycolate samples but had bacterial detection in the standard approach. In 4.7% (3/63) of the patients, only the sonication showed growth, whereas 25.4% (16/63) had no growth in sonication fluid but in one of the cultures. For S. caprae, there was a significantly different distribution (p=0.026) with more frequent detection in the group with thioglycolate at 37°C. The standard procedure (p=0.005) and sonication (p=0.023) showed a shorter time to positivity of the culture compared to the thioglycolate approach at 4°C. Conclusions. No general differences could be shown between the standard preparation and the thioglycolate preparation; in particular, storage at different temperatures does not seem to result in any difference. For individual cases (8% in this study), bacterial growth was detected in the thioglycolate group that would have been culture-negative otherwise. There might be organism dependent differences in growth in different media