The treatment of bone and joint infections (BJI) involving multi-drug resistant bacteria remains a challenge. MDR Our objective was to evaluate during a retrospective multicenter study the DFX minimal inhibitory concentrations (MICs) and compare its efficacy between ofloxacin-susceptible and ofloxacin-resistant Abstract Background
Purpose
Although described as a commensal bacterium with low pathogenicity, Cutibacterium acnes involvement has been reported in many clinical entities: infections associated with devices, such as shoulder prosthetic joint infections, osteosynthesis, breast implants or cerebrospinal fluid shunts. Various studies show that C. acnes grows as a biofilm, contributing to its persistence by allowing its escape from the action of the immune system and antibiotics. Our aim was to assess the activity of different active substances (erythromycin, clindamycin, doxycycline and Myrtacine®) on eight different well-characterized C. acnes strains after growth in biofilm mode.Background
Purpose
The diagnosis of periprosthetic joint infection (PJI) remains a challenge in clinical practice and the analysis of synovial fluid (SF) is a useful diagnostic tool. Recently, two synovial biomarkers (leukocyte esterase (LE) strip test, alpha-defensin (AD)) have been introduced into the MSIS (MusculoSkeletal Infection Society) algorithm for the diagnosis of PJI. AD, although promising with high sensitivity and specificity, remains expensive. Calprotectin is another protein released upon activation of articular neutrophils. The determination of calprotectin and joint CRP is feasible in a routine laboratory practice with low cost. Our objective was to evaluate different synovial biomarkers (calprotectin, LE, CRP) for the diagnosis of PJI.Background
Purpose
Bone and joint infections (BJIs) are serious infections requiring early optimized antimicrobial therapy. BJIs can be polymicrobial or caused by fastidious bacteria, and the patient may have received antibiotics prior to sampling, which may decrease the sensitivity of culture-based diagnosis. Furthermore, culture-based diagnosis can take up to 14 days. Molecular approaches can be useful to overcome these concerns. The BioFire® system performs syndromic multiplex PCR in 1 hour, with only a few minutes of sample preparation. The BioFire® Joint Infection (JI) panel (BF-JI), recently FDA-cleared, detects both Gram-positive (n=15) and Gram-negative bacteria (n=14), Candida, and eight antibiotic resistance genes directly from synovial fluids. The aim of this study was to evaluate its performance in acute JIs in real-life conditions. BF-JI was performed on synovial fluid from patients with clinical suspicion of acute JI, either septic arthritis or periprosthetic JI, in 6 French centers. The results of BF-JI were compared with the results of culture of synovial fluid and other concomitantly collected osteoarticular samples obtained in routine testing in the clinical microbiology laboratory.Aim
Method
Prospective study including 156 patients undergoing primary shoulder arthroplasty. In all the patients included 5 to 12 tissue samples were obtained and were specifically cultured to detect Aim
Method
we conducted a retrospective unmatched case-control study including all adult patients treated for mono and polymicrobial Aim
Method
The purpose of this study was to determine whether the ability to establish a biofilm varied according to the different subtypes of clinical strains of CA previously characterized and involved in BJI (hip, knee and shoulder prosthesis). The BioFilm ring test (BioFilm Control®) method with index determination, called BFI (BioFilm Index) inversely proportional to the level of biofilm production was used (BFI = 0.00 indicates a high production of biofilm Aim
Method
An acne Aim
Method
Although there are no treatment guidelines for The strain of PA ATCC11827 (MIC LVF = 0.25 mg/L) was used. The frequency of mutation was determined after inoculation of 108 PA on blood agar containing concentrations of 2 to 128 times the MIC incubated for 7 days in anaerobiosis at 35 ° C. The emergence of high-level of resistance was also studied from the low-level mutants after a second exposure. For the resistant mutants, the Aim
Method
From a large collection of 88 Aim
Method
Propionibacterium acnes is an emerging pathogen especially in orthopedic implant infection. Aim of this study was to investigate P. acnes phylogeny and to screen for virulence factors among a large collection of clinical isolates involved in spine material infections, arthroplasty infections and acne lesions. 88 P. acnes clinical isolates were collected between January 2003 and December 2014 at Nantes University Hospital (France). Fifty-eight isolates came from spine infections, 14 from prosthetic infections (knee, hip or shoulder), 14 from acne lesions and two reference strains (ATCC11827 and ATCC6919). Implant associated infections were confirmed using Infectious Diseases Society of America criteria for bone and joint infections. Phylotypes and Multi-Locus Sequence Typing (MLST) was carried out on all isolates as described by Lomholt et al. All isolates were tested by established PCR-based assays for 21 putative virulence factor genes characteristic of P. acnes. MLST analysis revealed an association between clonal complexes (CCs) and origin of P. acnes isolates (p = 0,027). Regarding CCs distribution between different origins, CC36 and phylotype II P. acnes isolates are more frequently observed in prosthetic joint infections. On the other hand, CC18 (IA) and CC28 (IB) P. acnes isolates are more frequently involved in spine infections and acne lesions. Among all virulence factors screened, hyaluronate lyase gene was only present in CC36 and phylotype II P acnes isolates. Other virulence factors were present in all isolates, whatever their origin or CC. Regarding molecular typing results, P. acnes involved in spine infections seem to have a skin origin (same CC as isolates from acne lesion). Interestingly, the origin of prosthetic joint infection isolates seems different and they all carry one more virulence factor. Hyaluronate lyase (Hyl) is a major surface protein of P. acnes with potential antigenetically variable properties that might be essential for P. acnes virulence. Increased tissue permeability caused by the action of hyaluronidase on the extracellular matrix appears to play a role in wound infections, pneumonia, and other sepsis such as bacteremia and meningitis. It could be also take a prominent part in P. acnes prosthetic joint infection pathogenesis.
Staphylococcus aureus is a leading cause of implant-associated infections (IAI). The aim of this study was to identify bacterial and/or clinical features involved in the pathogenesis of S. aureus IAI. 57 IAI S. aureus and 31 nasal carriage (NC) S. aureus isolates were studied. S. aureus genetic background was obtained by microarray analysis. Multi-Locus Sequence Typing was performed to determine clonal complexes (CC). The ability of S. aureus isolates to produce biofilm was investigated by resazurin and crystal violet methods. Clinical data were retrospectively collected from the patient's medical records. Fifty-five IAI patients were included. Two of them had two different S. aureus IAI episodes. The median age was 73 years (range: 21–96 years) with 29 women (52.7%). The main diagnosis for arthroplasty was arthrosis (38%). Implants were hip prosthesis (n=35), knee prosthesis (n=18) and osteosynthesis (n=4). Infectious and nasal carriage isolates belonged respectively to 18 and 13 different sequence types (STs) without significant difference. Among IAI isolates, five strains were methicillin resistant. IAI isolates were classified as strong (14%), moderate (42.1%) and weak (43.9%) biofilm producers. For NC isolates, distribution was 12.9%, 25.8% and 61.3% for strong, moderate and weak, respectively. Staphylokinase gene was associated with the occurrence of S. aureus IAI (p<0.001). Patients’ ABO blood group phenotype was associated with IAI S. aureus genetic background (sasG, slpB, lukD and set12/ssl8) (p≤0.01). In vitro, CC8 S. aureus strains produce more biofilm than others (p≤0.0001). Two alleles of bbp gene were significantly associated with CC8 S. aureus strains (p≤0.0001). No specific CC involved in IAI compared to NC S. aureus isolates was revealed. Our results suggested that occurrence of IAI may depend on patients’ ABO blood group and staphylokinase gene detection. We also observed a strong biofilm producer phenotype in CC8 S. aureus. Further studies are needed to prove whether one bbp gene variant is correlated to this phenotype. This study was supported by a grant number WS1106649 from Pfizer, France and by the French “Ministère de l'Enseignement Supérieur et de la Recherche”.
One of the most common pathogen causing musculoskeletal infections is Summary
Introduction
