Friday, July 21, 2017
Project co-funded by the European Commission in the framework of the 2nd Health Programme
Enter Title Minimize

2.1.1 Selecting the appropriate air quality for processing 

The TE can apply this FMEA risk assessment method to evaluate the risk of microbiological contamination of the tissue during processing. Microbes on the final tissue may originate from the donor or have been added during the processing steps. Donor selection is carried out to reduce the risk of transmission of inherent bacteria from the donor to the patient. Recovery of the tissue must be carried out as described in these good tissue practices, to minimize the risk of contamination. During further processing, no microbes should be added to the tissues and therefore processing steps are performed in a safety cabinet (Class A air quality) placed in a room with at least Class D air quality (minimum according to Directive 2006/86/EC) using sterile materials and equipment.

 

It is noted that skin has an intrinsic flora of commensal microbes. Several measures can be taken to remove this flora (washing with betadine, chlorohexidine or other antimicrobials).

 

The TE can use this FMEA tool to demonstrate the measures in place to reduce the risk of contamination during processing are acceptable. The following risk tool for defining the quality of the processing area can be used to evaluate each particular tissue and process.

 

Factor

1

3

5

7

9

Score

Risk that contaminants will not be detected in the tissue due to limitations of the sampling method

10% destructive testing in compliance with

European Pharmacopea.

Tissues preserved in culture

medium (contamination visible)

A biopsy of tissue tested  from every individual graft processed

Pieces of tissue tested for each process run (< 1% of the run)

Swabbing of final tissue

 

Risk of contamination during manipulation*

Tissue exposed to processing environment for < 1 hr

Tissue exposed to processing environment for 1-3 hr

Tissue exposed to  processing environment for 3-5 hr

Tissue exposed to processing environment for 5-7 hr

Tissue exposed to processing environment for > 7hr

 

Use of antimicrobials

Agents

with validated reduction of microbial contamination (by >3 logs)

Agents with published evidence of effective reduction of microbial contamination

(85% glycerol for skin processing)

Validated antibiotic

Cocktail treatment

Fluid storage and conditions in final container not promoting microbial growth (e.g. low temperature)

Fluid storage and conditions promoting microbial growth (temperature > 10 °C)

 

Risk of transfer of contaminants at transplantation a. Type of tissue

Acellular

No vital cells

Vital cells but no vessels

Vital cells and minor

vessels

Fully vascular with vital cells

 

Risk of transfer of contaminants at transplantation b. Type of use

Temporary superficial coverage < 3 weeks

Durable superficial coverage > 3 weeks

Durable implant in a poorly vascularised site

Small durable implant in a well vascularised site

Large durable implant in a well vascularised site

 

 

*To estimate this risk it is advised to perform ‘sham’ tissue manipulation sessions in the processing area using tissue containers with only the media used for the microbiology tests (‘media fill’).

 

The use of antimicrobials is a measure to reduce the risk of contamination during processing. Also, the risk of growth of micro-organisms in a graft stored in medium at 33°C is higher compared to a graft stored in the freezer.

 

To specify an appropriate air quality on the basis of the scores in the risk tool, the following is recommended as guidance:

< 20:            Class A with D background

20-29:           Class A with C background

> 30:           Class A with B background.

Print  
A3f Engine ::Terms Of Use::Privacy Statement