Multicenter evaluation of BioFire JI panel related to improved microbiological diagnostics on acute osteoarticular infections.

Microbiological diagnosis of osteoarticular infections (OI) is crucial for a successful treatment. A prospective multicenter study including 262 synovial fluids with suspicion of acute OI was performed between July 2021 and October of 2022. BioFire Joint Infection Panel multiplex-PCR test was performed and results were compared with conventional cultures of synovial fluid specimens. In total, 136 microorganisms were detected, and fourteen samples were positive for more than one microorganism. In monomicrobial infections (n = 87) agreement with culture was 69%. In 26 samples, the multiplex PCR yield an additional positive result when culture result was negative. It helped in the detection of fastidious microorganisms as K. kingae and N. gonorrhoeae. This multiplex PCR has proven to be a useful technique that can be used for patients with high suspicion of acute OI in a rapid and automated manner.

26Postoperative diagnosis and outcome in patients with revision arthroplasty for aseptic loosening.

BACKGROUND: The most common cause of implant failure is aseptic loosening (AL), followed by prosthetic joint infection (PJI). This study evaluates the incidence of PJI among patients operated with suspected AL and whether the diagnosis of PJI was predictive of subsequent implant failure including re-infection, at 2 years of follow up. METHODS: Patients undergoing revision hip or knee arthroplasty due to presumed AL from February 2009 to September 2011 were prospectively evaluated. A sonication fluid of prosthesis and tissue samples for microbiology and histopathology at the time of the surgery were collected. Implant failure include recurrent or persistent infection, reoperation for any reason or need for chronic antibiotic suppression. RESULTS: Of 198 patients with pre-and intraoperative diagnosis of AL, 24 (12.1 %) had postoperative diagnosis of PJI. After a follow up of 31 months (IQR: 21 to 38 months), 9 (37.5 %) of 24 patients in the PJI group had implant failure compared to only 1 (1.1 %) in the 198 of AL group (p < 0.0001). Sensitivity of sonicate fluid culture (>20 CFU) and peri-prosthetic tissue culture were 87.5 % vs 66.7 %, respectively. Specificities were 100 % for both techniques (95 % CI, 97.9-100 %). A greater number of patients with PJI (79.1 %) had previous partial arthroplasty revisions than those patients in the AL group (56.9 %) (p = 0.04). In addition, 5 (55.5 %) patients with PJI and implant failure had more revision arthroplasties during the first year after the last implant placement than those patients with PJI without implant failure (1 patient; 6.7 %) (RR 3.8; 95 % CI 1.4-10.1; p = 0.015). On the other hand, 6 (25 %) patients finally diagnosed of PJI were initially diagnosed of AL in the first year after primary arthroplasty, whereas it was only 16 (9.2 %) patients in the group of true AL (RR 2.7; 95 % CI 1.2-6.1; p = 0.03). CONCLUSIONS: More than one tenth of patients with suspected AL are misdiagnosed PJI. Positive histology and positive peri-implant tissue and sonicate fluid cultures are highly predictive of implant failure in patients with PJI. Patients with greater number of partial hip revisions for a presumed AL had more risk of PJI. Early loosening is more often caused by hidden PJI than late loosening.

[Osteoarticular pneumococcal infections observed in a tertiary hospital over a period of 11 years]. / Infección osteoarticular neumocócica en un hospital terciario durante un período de 11 años.

INTRODUCTION: Osteoarticular pneumococcal infection is an infrequent complication of pneumococcal bacteremia, due to the advances in antibiotic therapy and in the pattern of immunization. METHODS: A retrospective study was conducted on patients diagnosed with osteoarticular pneumococcal infection between January 2003 and December 2013 in the University Hospital Marqués de Valdecilla in Santander. RESULTS: Five out of 321 patients diagnosed with pneumococcal bacteremia had osteoarticular infection. All of them had at least one chronic underlying disease and had been immunized according to the standard vaccination schedule. Hip and vertebra were the most common joints involved. Outcome was favorable in all cases. CONCLUSIONS: The clinical findings of pneumococcal osteoarticular infection should be borne in mind. Its optimal prevention in high-risk patients should include the 13V conjugate vaccine.

High prevalence of cryofibrinogenemia in patients with chilblains during the COVID-19 outbreak.

BACKGROUND: Many cutaneous manifestations have been described in possible association with the COVID-19 pandemic, including acral lesions resembling chilblains. The underlying pathomechanisms of COVID-19 chilblains are not fully understood. The aim of this study was to describe the clinical, pathological, and laboratory findings of a series of patients who developed chilblains during the COVID-19 outbreak and to investigate the possible factors that could be involved in the pathogenesis of these lesions. METHODS: We conducted a prospective cohort study that included 54 patients who presented with chilblains during the highest peak in the incidence of COVID-19 in Cantabria (northern Spain). Skin biopsies were performed on 10 of these patients who presented with recent lesions. Laboratory investigations, including immunological analysis, serological studies, and the assessment of cryoproteins, were also performed. RESULTS: Most patients presented erythematous plaques located on the toes and/or purpuric macules located on the feet. Histopathological findings were compatible with those of idiopathic chilblains. Immunohistochemical evaluation showed C3d and C4d deposits in the vessel walls in seven cases. The autoimmunity panel was negative in most of our series. Cryoprotein testing showed positive cryofibrinogen in two-thirds (66.7%) of the patients assessed. On follow-up, most patients presented almost complete resolution, although six patients required prednisone and antiaggregant drug treatment. CONCLUSIONS: This study shows, for the first time to our knowledge, a high prevalence of cryofibrinogenemia in patients with chilblains during the COVID-19 pandemic. Cryofibrinogenemia could be implicated in the pathogenesis of chilblains related to COVID-19.