Pathogenic potential ofEscherichia coliclinical strains from orthopedic implant infections towards human osteoblastic cells

Abstract

Escherichia coli is one of the first causes of Gram-negative orthopedic implant infections (OII), but little is known about the pathogenicity of this species in such infections that are increasing due to the ageing of the population. We report how this pathogen interacts with human osteoblastic MG-63 cells in vitro, by comparing 20 OII E. coli strains to two Staphylococcus aureus and two Pseudomonas aeruginosa strains. LDH release assay revealed that 6/20 (30%) OII E. coli induced MG-63 cell lysis whereas none of the four control strains was cytotoxic after 4 h of coculture. This high cytotoxicity was associated with hemolytic properties and linked to hlyA gene expression. We further showed by gentamicin protection assay and confocal microscopy that the non-cytotoxic E. coli were not able to invade MG-63 cells unlike S. aureus strains (internalization rate <0.01% for the non-cytotoxic E. coli versus 8.88 ± 2.31% and 4.60 ± 0.42% for both S. aureus). The non-cytotoxic E. coli also demonstrated low adherence rates (<7%), the most adherent E. coli eliciting higher IL-6 and TNF-α mRNA expression in the osteoblastic cells. Either highly cytotoxic or slightly invasive OII E. coli do not show the same infection strategies as S. aureus towards osteoblasts.

A New Antibiotic-Loaded Sol-Gel Can Prevent Bacterial Prosthetic Joint Infection: From in vitro Studies to an in vivo Model

“…The microbiological results from the in vivo study revealed that moxifloxacin-loaded sol-gel showed an all-or-nothing response when used to coat the implant and S. aureus or E. coli infection is induced (Figure 11) as expected. The femoral deformation observed in S. aureusinfected groups with non-coated implants is consistent with the ability of S. aureus to internalize in osteoblasts (Cremet et al, 2015) and cause deforming osteomyelitis in chronic bone infections (de Mesy Bentley et al, 2017) (Figure 10). In the case of E. coli, the bone deformation observed in infected groups FIGURE 13 | Immunohistochemistry for markers of different bone cells.…”

Interaction of Cutibacterium ( formerly Propionibacterium) acnes with bone cells: a step toward understanding bone and joint infection development

“…Bacterial internalization experiments were adapted from Crémet et al . study 28 . Briefly, the MG-63 monolayers were infected for 2 h (multiplicity of infection (MOI) of 100:1).…”

Photoacoustic Molecular Imaging: From Multiscale Biomedical Applications Towards Early-Stage Theranostics

“…More work should be done to circumvent this type of detector’s bottlenecks, some of which include inhomogeneous spatial resolution, limited imaging depth, and acoustic mismatches especially for the human skull [39, 47]. PACT with a high frame rate, tunable laser sources, a well-designed acoustic array and a corresponding reconstruction algorithm are necessary to attract more clinical attention.…”