Systematic enhancement of microbial decontamination efficiency in bone graft processing by means of high hydrostatic pressure using Escherichia coli as a model organism

This study aims to investigate the ability of high-pressure decontamination and to establish a treatment protocol that is able to successfully inactivate microorganisms with the final goal to sterilize bone specimens. UsingEscherichia coli (E. coli) as a model organism, HHP treatment parameters like temperature and duration, pressurization medium, and the number of treatment cycles were systematically adjusted to maximize the efficiency of inactivating logarithmic and stationary phase bacteria. Towards that we quantified colony-forming units (cfu) after treatment and investigated morphological changes via Field Emission Scanning Electron Microscopy (FESEM). Additionally, we tested the decontamination efficiency of HHP in bovine cancellous bone blocks that were contaminated with bacteria. Finally, two further model organisms were evaluated, namelyPseudomonas fluorescens as a Gram-negative microorganism andMicrococcus luteus as a Gram-positive representative. A HHP protocol, using 350  MPa, was able to sterilize a suspension of stationary phaseE. coli, leading to a logarithmic reduction factor (log RF) of at least −7.99 (±0.43). The decontamination of bone blocks was less successful, indicating a protective effect of the surrounding tissue. Sterilization of 100% of the samples was achieved when a protocol optimized in terms of treatment temperature, duration, pressurization medium, and number and/or interv al of cycles, respectively, was applied to bone blocks artificially...
Source: Journal of Biomedical Materials Research Part B: Applied Biomaterials - Category: Materials Science Authors: Tags: RESEARCH ARTICLE Source Type: research