There is a lack of data supporting the use of doxycycline as a single agent after removing infected orthopaedic metalwork. We evaluated the efficacy and safety of doxycycline compared with other single antibiotic regimens used at our specialist orthopaedic hospital. A retrospective observational study including all adult patients diagnosed with an orthopaedic metalwork infection due to staphylococci. All patients were managed with the removal of metalwork, and multiple intraoperative samples were sent for culture, followed by the administration of at least four weeks of oral antibiotics. Antibiotic selection was on the recommendation of an infection consultant. Infection outcome was assessed as the proportion of patients meeting the OVIVA Trial definition of definite failure at follow-up. The probability of definite failure for doxycycline and the alternatives group was estimated using the Kaplan-Meier survival method. All adverse drug reactions (ADR) during treatment were analysed.Aim
Methods
Management of bone and joint infection can be technically complex and often requires a prolonged course of antibiotics. Traditionally, bone and joint infection management utilises nurse-led outpatient parenteral antibiotic therapy (OPAT) where adherence is unlikely to be an issue. However, with increasing evidence in favour of oral therapy, the question of adherence merits further consideration. We describe the adherence of both oral (PO) and self-administered intravenous (IV) antibiotics in the treatment of bone and joint infection using paper questionnaires (8-item Modified Morisky Adherence Score (MMAS)) and, in a subset of participants, electronic pill containers (Medication Event Monitoring Systems*). All eligible participants enrolled in the OVIVA trial (2010–2015) were randomised to six weeks of either PO or IV antibiotic treatment arms. Self-administering patients were followed up with questionnaires at day 14 and 42. A subset of PO participants was also given the medication event monitoring system* in order to validate the adherence questionnaires. The results were correlated with treatment failures at one-year follow-up.Aim
Method
Fungi are a rare and devastating cause of Periprosthetic Joint Infection (PJI). Diagnosis and treatment is a challenge as there are currently no specific guidelines. A recently published review identified 75 case reports of fungal PJI. The aim is to describe our experience of treating fungal PJI since 2011 within the Bone Infection Unit at our institution.Introduction
Aim
Diagnosing Orthopaedic infection is limited by the sensitivity of culture methods. Next generation sequencing (NGS) offers an alternative approach for detection of microorganisms from clinical specimens. However, the low ratio of pathogen DNA to human DNA often inhibits detection of microorganisms from specimens. Depletion of human DNA may enhance the detection of microbial DNA1. Our aim was to compare four DNA extraction methods for the recovery of microbial DNA from orthopaedic samples for NGS. Simulated samples; pooled culture negative sample matrix was spiked with known concentrations of microorganisms, each panel consisting of 7 samples. Broth culture was performed on simulated samples for comparison with NGS DNA Extraction; total nucleic acid extraction was performed on an automated extraction platform Detection of human and microbial DNA; human endogenous (HE) gene rtPCRAim
Method
Beadmill processing combined with automated blood culture bottle methods (BACTEC™) has a greater sensitivity and specificity, and a shorter time to positivity compared with primary plates (PP) for prosthetic joint infection (PJI) diagnosis but the clinical impact of Bactec on antimicrobial therapy has not yet been evaluated. We compared time-to-positivity of Columbia agar with horse blood plates (BA) and chocolatized horse blood plates (CHOC) versus anaerobic (ANA) and aerobic blood culture bottles (02) in patients with PJI. We compared the contributions of the two methods to the commencement of effective and targeted antimicrobial therapy. Retrospective observational study from June 2013 to March 2014. Inclusion criteria were confirmed PJI (IDSA criteria) with at least 2 perioperative samples. After beadmill processing BA and CHOC plates were incubated for 2 days and discarded if negative, BactecTM bottles were incubated for 14 days and sub-cultured if positive. MALDI-TOF (Microflex, Brucker) was used for identification and all isolates had sensitivities performed (Phoenix, BD). Standard empirical antibiotic treatment was teicoplanin, piperacillin/tazobactam and amikacin. We defined time to switch as difference between date of sample collection and date of commencing targeted or effective therapy; prior antibiotic therapy was defined as the use of antibiotics within 14 days before samples collection. Fifty cases were identified during the study period. 330 microbiological isolates were included: 24 (7.3%) were considered contaminants; 153 isolates (50.0%) were detected both from BactecTM and PP; 152 (49.7%) from BactecTM only; 1 isolate (0.3%) from PP only. 17 (34%) diagnoses of PJI was made exclusively by BactecTM. The majority of isolates on BA and CHOC plates grew in the first 24 hours (81.2% and 77.5% respectively). 293/305 isolates from BactecTM (96.1%) grew in the first 2 days. Antibiograms were available after 2.5 days from PP versus 4 days from BACTEC (p<0.0001). When we compared time to switch from empiric to targeted therapy, no difference was seen between patients with positive BACTEC cultures only (median 4 days, range 2–15) versus patients with positive PP cultures, (median 5 days, range 2–9) (p=0.984). Where organisms were resistant to empirical therapy, PP results did not contribute to switching to effective therapy. Prior antibiotic therapy had no impact on time-to-positivity for both methods (R=−0.005, p=0.936). Compared to BACTEC cultures for the diagnosis of PJIs, primary plate cultures did not provide additional diagnostic information and did not significantly reduce the time to effective or targeted antimicrobial therapy.
