A novel DNA profiling application for the monitoring of cross-contamination in autologous chondrocyte implantation

BACKGROUND

Autologous chondrocyte implantation (ACI) is a cell-based treatment that can be used to regenerate chondral defects. European legislation specifically classifies such produced chondrocytes as "medicinal for advanced cell therapy" that have to be manufactured in pharmaceutical factories according to specific rules, named Good Manufacturing Practices (GMPs). One main requirement of cell manipulation in advanced therapy is to prevent the risk of any contamination.

AIM

The aim of this study was to verify if chondrocyte cultures suitable for ACI were free of cross-contamination by means of DNA profiling techniques.

MATERIALS AND METHODS

Cell cultures were carried on in a Hospital Cell Factory in compliance with European current Good Manufacturing Practices. DNA profiling, by means of Short Tandem Repeats and miniShort Tandem Repeats analyses, was performed on expanded chondrocytes and their related control blood samples. Mitochondrial DNA was analysed to further confirm the results and to evaluate possible mutations occurred in the samples.

RESULTS

Our findings demonstrated the absence of cross-contamination between chondrocyte cultures and, thus, their identity maintenance until the end of the manipulation.

CONCLUSIONS

DNA profiling technique can be a suitable test for quality control not only for chondrocyte manipulation, but for cell therapy in general.

[In vitro evaluation of bactericidal activity of an over-heated saturated dry atomized steam electro-medical device on inert contaminated surfaces]

Surface disinfection together with cleaning practises and aseptic procedures are established measures for effective prevention of infectious diseases reducing infection risks. In this study, we evaluated the bactericidal effectiveness in vitro of the electro-medical device Sani System, an over-heated saturated dry-steam disinfection system, against predetermined bacterial load dried on inert surfaces. In particular we have tested different materials, representative of operating rooms furnishing and walls commonly used in healthcare setting, with Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii. As a result of treatment, the mean bacterial load on all the test surfaces was reduced by a factor of 102 in the contact plate experimental study and by a factor of 10 in the total bioburden experimental study. The Sani System Polti proved to be efficacious in killing 100% of the bacteria in all experimental conditions, therefore it could help to reduce the risk of spreading nosocomial infections in healthcare facilities.

Bacterial contamination of musculoskeletal allografts

Based on the indications in the literature of the transmission of highly pathogenic bacteria in musculoskeletal allograft implants, the cultural results for allografts removed and implanted in conditions of asepsis between 1997 and 2000 in BTM were analyzed: 4014 allografts (3117 from a living donor, 897 from a cadaver) and 3479 implants (2191 with allografts from living donors and 1288 with allografts from cadavers). Explanted tissues: these were positive to culture in 292 out of 3117 (9.4%) allografts from living donors; the bacteria isolated showed low pathogenicity. Out of 897 allografts 117 cadaver donors bacteria with low pathogenicity were isolated in 68 (7.6%) and high pathogenicity in 12 (1.3%). Implants: cultures were positive in 116/2191 (5.3%) implants with allografts from living donors and in 55/1288 (4.3%) implants with allografts from cadavers. The bacteria isolated are the same as those shown in the explants. In living donors contamination is similar as regards incidence and type of microorganism to that observed in surgical theatres during routine surgery. Contamination seems to be greater in allografts removed from cadavers who died as a result of trauma, in the presence of positive hemocultures, prolonged catheterization and intubation, explantation of the pelvis and removal of several organs and tissues prior to musculoskeletal allograft.