Inoculating Biopsy Forceps to Evaluate Cleaning Procedures
The objective of this simulated-use testing is to evaluate cleaning
procedures for biopsy forceps. In this testing, single use biopsy forceps
are used because they may most easily be subjected to destruction testing.
Methods
Prepare biopsy forceps intended for testing in a class IIB biosafety cabinet
wearing appropriate personal protective equipment. Soil using Artificial
Test Soil (ATS), which is formulated to mimic worst case soiling expected in
gastrointestinal endoscopy procedures and allows for quantitative assessment
of cleaning efficacy for protein, carbohydrate, hemoglobin, and endotoxin.
Bioburden
Supplement ATS with approximately 106 colony-forming units (cfu)/mL of
Enterococcus faecalis (ATCC 29212) as well as approximately 106 cfu/mL of
Geobacillus stearothermophilus (ATCC 12980) spores. Inoculum counts should
be performed to confirm the concentration of both organisms for all
experiments.
Test Devices and Inoculation Procedure
The test devices are new biopsy forceps. This type of biopsy forceps has an
friction-reducing sheath (Endoglide), a working length of 240 cm, an outside
jaw diameter of 3.3 mm, and is for use with a biopsy channel that has a
minimum internal diameter of 3.8 mm. To inoculate the forceps with ATS,
utilize a retroflush lumen adaptor from Medisafe. Force soil upwards
through the retroflush lumen adaptor into the forcep until excess soil is
noted exiting at the handle. Store inoculated SBFs at room temperature for 2
hours, then clean with the method(s) being evaluated.
Test Methods
Quantitative indirect evaluation of soil parameters and count of viable
organisms:
After cleaning single use forceps with method being evaluated, aseptically
cut up into approximately 4.5-cm lengths. Pool the segments from each
separate forcep a 50-mL sterile test tube. Stand each segment vertically
within the test tube. Once the entire length of the forcep (excluding the
handle) is cut up, completely immerse in 25 mL of sterile, reverse osmosis –
purified water to the test tube. Mix the tube containing the forcep segments
in a vortex mixer for 1 minute; Sonicate for 4 pulses of 5 seconds each;
Centrifuged at 3,500 rpm for 10 minutes at 4
oC (to ensure that
all lumens are perfused with liquid); and mix by a vortex mixer for an
additional 1 minute. Use the eluted sample to test for protein,
carbohydrate, hemoglobin and endotoxin. Count viable organisms by spreading
0.1 mL of each dilution of the sample over the surface of 2 tryptic soy agar
plates; incubate one set of inoculated plates at 55
oC (to detect
G. stearothermophilus); Incubate the other set at 35
oC (to detect
E. faecalis).
An example of utilizing this method for testing can be found here:
http://www.journals.uchicago.edu/ICHE/journal/issues/v27n8/2005092/2005092.web.pdf
