Lithograph-moulded poly-L-co-D,L lactide porous membranes for osteoblastic culture

Pore size, shape, wall morphology, porosity, and interconnectivity are important characteristics of the scaffolds. Lithography is a manufacturing technique that allows the production of tridimensional scaffolds with a controllable and reproducible inner architecture. The aim of this study was to use lithography to create a poly-L-co-D,L lactide (PLDLA) scaffold with symmetrical pore size and distribution, and to evaluate its biocompatibility with osteoblasts in vitro. Lithographic moulds were used to produce porous PLDLA membranes by a casting procedure. Osteoblasts were removed from calvarial bones and seeded onto porous and smooth PLDLA membranes after which cell viability and adhesion assays, cytochemical analysis and scanning electron microscopy were used to characterize the cells. Cell viability and adhesion assays, cytochemical analysis, and scanning electron microscopy were carried out. Cell viability was similar on porous and smooth PLDLA membranes but higher than on a polystyrene substrate (positive control). Although osteoblasts adhered to the surface of all the materials tested, cell adhesion to lithographed PLDLA was greater than to smooth PLDLA membranes. In conclusion, osteoblasts interacted well with PLDLA membranes, as shown by the viability and adhesion assays and by the enhanced collagen production17171

The 2023 Orthopedic Research Society's international consensus meeting on musculoskeletal infection: Summary from the in vitro section

Antimicrobial strategies for musculoskeletal infections are typically first developed with in vitro models. The In Vitro Section of the 2023 Orthopedic Research Society Musculoskeletal Infection international consensus meeting (ICM) probed our state of knowledge of in vitro systems with respect to bacteria and biofilm phenotype, standards, in vitro activity, and the ability to predict in vivo efficacy. A subset of ICM delegates performed systematic reviews on 15 questions and made recommendations and assessment of the level of evidence that were then voted on by 72 ICM delegates. Here, we report recommendations and rationale from the reviews and the results of the internet vote. Only two questions received a ≥90% consensus vote, emphasizing the disparate approaches and lack of established consensus for in vitro modeling and interpretation of results. Comments on knowledge gaps and the need for further research on these critical MSKI questions are included

Biofilm formation by clinical isolates and the implications in chronic infections

<p>Abstract</p> <p>Background</p> <p>Biofilm formation is a major virulence factor contributing to the chronicity of infections. To date few studies have evaluated biofilm formation in infecting isolates of patients including both Gram-positive and Gram-negative multidrug-resistant (MDR) species in the context of numerous types of infectious syndromes. Herein, we investigated the biofilm forming capacity in a large collection of single patient infecting isolates and compared the relationship between biofilm formation to various strain characteristics.</p> <p>Methods</p> <p>The biofilm-forming capacity of 205 randomly sampled clinical isolates from patients, collected from various anatomical sites, admitted for treatment at Brooke Army Medical Center (BAMC) from 2004–2011, including methicillin-resistant/methicillin susceptible <it>Staphylococcus aureus</it> (MRSA/MSSA) (n=23), <it>Acinetobacter baumannii</it> (n=53), <it>Pseudomonas aeruginosa</it> (n=36), <it>Klebsiella pneumoniae</it> (n=54), and <it>Escherichia coli</it> (n=39), were evaluated for biofilm formation using the high-throughput microtiter plate assay and scanning electron microscopy (SEM). Relationships between biofilm formation to clonal type, site of isolate collection, and MDR phenotype were evaluated. Furthermore, in patients with relapsing infections, serial strains were assessed for their ability to form biofilms <it>in vitro</it>.</p> <p>Results</p> <p>Of the 205 clinical isolates tested, 126 strains (61.4%) were observed to form biofilms <it>in vitro</it> at levels greater than or equal to the <it>Staphylococcus epidermidis</it>, positive biofilm producing strain, with <it>P. aeruginosa</it> and <it>S. aureus</it> having the greatest number of biofilm producing strains. Biofilm formation was significantly associated with specific clonal types, the site of isolate collection, and strains positive for biofilm formation were more frequently observed to be MDR. In patients with relapsing infections, the majority of serial isolates recovered from these individuals were observed to be strong biofilm producers <it>in vitro</it>.</p> <p>Conclusions</p> <p>This study is the first to evaluate biofilm formation in a large collection of infecting clinical isolates representing diverse types of infections. Our results demonstrate: (1) biofilm formation is a heterogeneous property amongst clinical strains which is associated with certain clonal types, (2) biofilm forming strains are more frequently isolated from non-fluid tissues, in particular bone and soft tissues, (3) MDR pathogens are more often biofilm formers, and (4) strains from patients with persistent infections are positive for biofilm formation.</p