BIOTECH-GERMANDE. Test report written by: Dr Marlène RICHARD. Marseille: October 24 th, 2007

Transcription

1 EVALUATION OF THE CLEANING EFFICACY OF A BRUSHING PROCEDURE OF ENDOSCOPE CHANNELS USING 2.8 MM BALL BRUSHES" (CBC) Test report written by: Dr Marlène RICHARD Marseille: October 24 th, 2007 Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 1/14

2 CONTENT I : DESCRIPTION OF THE STUDY :...3 II : OBJECTIVE :...3 III : PRINCIPLE :...3 IV : MATERIAL AND METHOD :...4 a) Brushes :...4 i) "Standard" brush (see. picture n 1) : 4 ii) "Ball brushes" (see. picture n 2): 4 b) Detergent:...4 c) Bacterial strain :...4 d) Culture medium :...5 i) Maintenance and counting medium : 5 ii) Biofilm broth : 5 iii) Recovering solution : 5 iv) Proteins measurement : 5 v) PTFE tube : 5 V : METHOD :...6 a) Biofilm formation :...6 i) Test equipment (Figure N 1): 6 ii) Pumps : 6 iii) Inoculation of the loop : 6 iv) Sampling of PTFE tube portions : 6 b) Determination of the cleaning efficacy :...7 i) Determination of the number of viable bacteria still fixed to the PTFE tube: 7 ii) Determination of the residual amount of proteins on the internal surface of the tested PTFE tube : 7 VI : RESULTS :...8 VII : CONCLUSIONS :...14 VIII : STATEMENT OF GOOD LABORATORY PRACTICE:...14 Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 2/14

3 I : DESCRIPTION OF THE STUDY : Title: Internal reference: Sponsor: Evaluation of the cleaning efficacy of a brushing procedure of endoscope channels using "ball brushes" (CBC). Study N : 547.CBC.07 CBC (Deutschland) GmbH Medical Device Division Hansaallee 191 D DUSSELDORF Contact: M SASAKI Test period: to Study manager: Tests Manager: Test laboratory: Dr Marlène RICHARD. Audrey RIBIOLLET Laboratoire Parc Scientifique de Luminy 163 Avenue de Luminy Case Marseille Cedex 9 II : OBJECTIVE : Evaluate the efficacy of a cleaning procedure of endoscope channels using "ball brushes" compare to standard brushes against Pseudomonas aeruginosa biofilm formed on the internal surface of a 2.8 mm diameter PTFE test tube. III : PRINCIPLE : 2.8 mm diameter PTFE test tubes were artificially contaminated with a mono-bacterial Pseudomonas aeruginosa biofilm according to a pre-defined experimental protocol. After obtaining a homogeneous and stable biofilm, 150 mm long PTFE test tube portions (contaminated on their inner surface with the biofilm), were removed and subjected to the brushing procedure. The cleaning efficacy of each brushing procedure tested ( standard brush versus "ball brushes") was quantified by determining after each passage of the brush: - The evolution of the number of viable bacteria still fixed to the biofilm; - The evolution of the residual quantities of proteins on the surface of the test support. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 3/14

4 IV : MATERIAL AND METHOD : a) Brushes : i) "Standard" brush (see. picture n 1) : Type of product: Single use brush for 2.8 mm to 3.2 mm inner diameter channels Product reference: SU Lot number: O 2607 Manufacturer: LTA medical Brush diameter: 4 mm ii) "Ball brushes" (see. picture n 2): Type of product: single-use ball brushes. Product reference: NC Lot number: NC Manufacturer: CBC Delivery date: September 17 th, 2007 Diameter: 2.8 mm Picture n 1: "Standard" brush Picture n 2: "Ball brushes" (CBC) b) Detergent: Name: Cleantop C21 Type of product: Detergent Internal reference: 547.CBC Delivery date: September 17 th, 2007 c) Bacterial strain : Pseudomonas aeruginosa CIP A22 Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 4/14

5 d) Culture medium : i) Maintenance and counting medium : Trypticase soja : Biomerieux, Internal reference: B ii) Biofilm broth : Composition of the nutrient broth used to supply the loop and promote biofilm formation: Casamino acids (Difco ) Yeast extract (Sigma Y1625) MgSO4, 2H 2 O (Fluka 61138) FeSO4, 7H 2 0 (Sigma F2387) Na2HPO4 anhydrous (Sigma S9763) KH2PO4 (Sigma P0662) Lactose (Prolabo ,) Internal reference: 0.1g/l 0.1 g/l 0.2 g/l g/l 1.25 g/l 0.5 g/l g/l B , B iii) Recovering solution : Lecithin (SIGMA, P-5394) 2% (w/v) Sodium thiosulfate (SIGMA, S-8503) 0.5 %(w/v) Polysorbate 80 (SIGMA, P-1754) 10% (w/v) Histidine (SIGMA, H-8000) 1% (w/v) Trypticase soya broth (Biomerieux, 51019) qs.ad. 100ml Internal reference B iv) Proteins measurement : UPTIMA kit UP75860A Lot n G03KL56 v) PTFE tube : Model provided by CBC Delivery date: October 3 rd, 2007 Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 5/14

6 V : METHOD : a) Biofilm formation : i) Test equipment (Figure N 1): C A B ii) Pumps : Figure 1: Test equipment for biofilm formation on PTFE tube (2.8 mm internal diameter). 1: Biofilm broth, 2: 30 C water bath, 3 and 4: peristaltic pumps. Two pumps are respectively used: - To supply the loop with the biofilm broth (pump N 3). The flow is adjusted between 1.7 and 2.0 ml/min. - To ensure a circulation of the broth in the loop (pump N 4) with a speed rotation of about 40 rpm, that is to say 100 ml/min (laminar flow). The 180 cm long portions of PTFE test tube, intended to be used for tests, are positioned in the circuit (between points A and B). The entire experimental set-up described in figure 1 is placed under a laminar flow cabinet. iii) Inoculation of the loop : After having filled the circuit with the adhesion broth, the loop is inoculated by injecting (at point C level) 5 to 10 ml of a bacterial suspension containing approximately 10 8 bacteria per ml (pump N 3 turned off). The system is maintained under agitation (pump N 4 running) for 20 minutes before turning on the supply pump. The system is maintained in an incubator at (30 ± 2) C for 72 h to 96 h iv) Sampling of PTFE tube portions : After an incubation of about 72 hours, pumps N 3 and N 4 are momentarily stopped and portions of PTFE test tubes intended to be used for the tests are removed from the circuit after disinfection of their outer surfaces with alcohol 75. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 6/14

7 b) Determination of the cleaning efficacy : The PTFE tube portions sampled (see V.a.vi) are subjected to the tested procedure. Six brushing procedures with water (0.2 µm filtered water) are tested and compared: 1 ball brush compared to the standard brushing (backward); 2 ball brushes compared to the standard brushing (backward and forward); 3 ball brushes compared to the standard brushing (twice backward and once forward). Six brushing procedures with 0.5% (v/v) C21 detergent solution are also tested and compared: 1 ball brush compared to the standard brushing (backward); 2 ball brushes compared to the standard brushing (backward and forward); 3 ball brushes compared to the standard brushing (twice backward and once forward). For each procedure, 2 x 1.5 mm length at each end of the PTFE tube are cut and used as control pieces to determine both the initial amount of bacteria and proteins of the biofilm in the PTFE test tube. After each tested procedure, PTFE tube portions of 90 mm length are rinsed with 50 ml of distilled water, cut into 6 portions of 15 mm lenght PTFE tube and analyzed to determine: The number of viable bacteria still fixed to the internal surface of the PTFE test tube (V-b-i) The residual quantities of proteins remaining on the internal surface of the PTFE test tube (V-b-ii). i) Determination of the number of viable bacteria still fixed to the PTFE tube: For each tested procedure, three portions of 15 mm lenght PTFE tube are immersed individually in 10 ml of recovering solution and cut longitudinally into four identical sections. Five grams of sterile glass beads are added to the test tube containing the PTFE tube portion and the recovering solution and shake (Vortex 2, shake 5, Scientific Industries, Bioblock, France) for exactly 1 minute. The aim of this operation is to detach all microorganisms still fixed to the surface. From these 10 ml of neutralizing solution, a series of ten fold dilutions is performed and 2 x 1 ml of each of these dilutions are included in trypticase soya agar (Biomérieux). After 24 to 48 hours of incubation at 37 C under aerobic conditions, the number of colonies forming units (CFU) are counted and the results expressed as a number of viable bacteria per cm 2 of PTFE test tube (N t ). ii) Determination of the residual amount of proteins on the internal surface of the tested PTFE tube : After each tested procedures, three portions of 15 mm lenght PTFE tube are dipped in 3 ml of sterile distilled water and cut in half lenghtwise. Both halves are scraped thoroughly in order to suspend residual proteins from the internal surfaces of the PTFE tube portion. The residual amounts of protein per cm² of PTFE tube ([Prot.assay ]) are determined from these 3 ml using the MicroBC test method. Concurrently to main tests, a portion of sterile PTFE tube (blank) is subjected to the same treatment than the test tube and tested for residual proteins in order to determine any possible interference between tested products and the method used for proteins measurement. Results obtained are noted [Prot. blank ]. From that time, protein concentrations remaining on the surface of the test tube after each procedure ([Proteins]) are calculated as indicated below: [Proteins] = [Prot. assay ] - [ Prot. blank ] Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 7/14

8 VI : RESULTS : Contro l BALL BRUSHES + water BALL BRUSHES + C21 detergent Fixed bacteria x (log 10 nb. CFU/cm²) [Proteins] (µg/cm²) Fixed bacteria x x (log 10 nb. CFU/cm²) [Proteins] x (µg/cm²) x = mean, =standard deviation Table N 1: Activity of the 2 brushing procedures using ball brushes on PTFE tube contaminated with Pseudomonas aeruginosa CIP A22 biofilm. Evolution of the number of viable bacteria (log 10 ) present in the biofilm and residual protein amounts ([Proteins]) on the internal surface of the PTFE tube, according to the number of ball brushes used. Contro l STANDARD BRUSHES + water STANDARD BRUSHES + C21 detergent Fixed bacteria x (log 10 nb. CFU/cm²) [Proteins] (µg/cm²) Fixed bacteria x x (log 10 nb. CFU/cm²) [Proteins] x (µg/cm²) x = mean, =standard deviation Table N 2: Activity of the 2 brushing procedures using standard brushes on PTFE tube contaminated with Pseudomonas aeruginosa CIP A22 biofilm. Evolution of the number of viable bacteria (log 10 ) present in the biofilm and residual protein amounts Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 8/14

9 ([Proteins]) on the internal surface of the PTFE tube, according to the number of passages. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 9/14

10 Values of the number of viable bacteria and amounts of protein remaining on the surface of the test tube according to number of passages of the "standard brush and ball brushes are presented in table 1 for the procedure using ball brushes and in table 2 for the standard brushing. Figures 2 and 3 show for the twelve tested procedures, the evolution of the number of viable bacteria on the surface of the test tube (Figure 2) and the evolution of residual protein amount (Figure 3). The analysis of the evolution of the number of viable bacteria present on the surface of the PTFE test tube (see figure 2) indicates that the ball brush procedures using one, two and then three ball brushes, with or without detergent, induce an appreciable decrease of the number of viable bacteria still fixed to the surface compared to the results observed with the related standard brushing procedures. For ball brushes, the number of viable bacteria per surface unit decreases after 3 ball brushes from 1.3 x 10 9 CFU/cm 2 to 1.4 x 10 2 CFU/cm 2 (i.e. reduction of about 7.1 logarithmic units) when ball brushes are used with water to 1.1 x 10 2 CFU/cm 2 (about 7.2 logarithmic units reduction) when they are used in combination with the C21 detergent. For standard brushing procedures, a relatively linear and less important decrease of the number of viable bacteria present on the surface of the test tube is observed. The number of viable bacteria per surface unit decreases after 3 passages (2 backward and 1 forward motions) from 1.3 x 10 9 CFU/cm 2 to 1.9 x 10 5 CFU/cm 2 (about 3.9 logarithmic units reduction) when standard brushes are used with water to 3.6 x 10 6 CFU/cm 2 (about 2.4 logarithmic units reduction) when they are used in combination with the C21 detergent. The number of remaining viable bacteria is significantly lower after the 3 ball brushes procedures (p<0.0001) with or without C21 detergent compared to the standard brushing procedure. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 10/14

11 9,00 [viable fixed bacteria] (log Nb CFU/ cm²) 8,00 7,00 6,00 5,00 4,00 3,00 2,00 Ball brush + water Standard brush + water Ball brush + C21 Standard brush + C21 1,00 0,00 Cont rol Nb of ball brush or standard brush passages Figure 2: Activity of the 2 brushing procedures against PTFE tube contaminated with Pseudomonas aeruginosa CIP A22 biofilm. Evolution of the number of viable bacteria (log 10 ) present in the biofilm according to the number of ball brushes or passages of the standard brushes. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 11/14

12 The analysis of the evolution of residual amount of proteins remaining on the surface of the test tube (see tables 1 and 2 and figure 3) confirms that the first ball brush and the first standard brushing procedure (backward motion) induce an important and rapid decrease of the residual amount of protein. After one passage, the reduction of the initial amount of proteins is about 95.7% when standard brushes are used in combination with water and 90.5% when they are used with C21 detergent. When one ball brush is used in combination with water, the reduction of the initial amount of proteins is about 94.9% and 87.4% when it is used with C21 detergent. Differences between mean values obtained for ball brushes and the standard brushing procedure are statistically not significant (p>0.4). This first decrease, observed both with ball brushes and standard brushing procedures, is then followed by a stabilization of protein amounts to values lower than 9.0 ± 3.0 µg/ cm 2 i.e. at least 90% reduction of the initial amount of protein present on the PTFE tube. There is no statistical difference between the efficacy of the brushing procedures performed with ball brushes or standard brushes whatever number of ball brushes or passages of the standard brushes is being used. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 12/14

13 120,0 100,0 Ball brush + water Standard brush + water Ball brush + C21 Standard brush + C21 [Proteins] (µg/ cm²) 80,0 60,0 40,0 20,0 0,0 Control Nb of ball brushes or standard brush passages Figure 3: Activity of the 2 brushing procedures against PTFE tube contaminated with Pseudomonas aeruginosa CIP A22 biofilm. Evolution of residual amounts of protein on the surface of the test tube according to the number of ball brushes or passages of the standard brushes. Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 13/14

14 VII : CONCLUSIONS : When tested against a Pseudomonas aeruginosa CIP A22 biofilm formed on 2.8 mm PTFE tube, the difference in cleaning efficacy regarding protein removal between the brushing procedure using 2.8 mm ball brushes and the standard brushes is statistically not significant whatever the number of ball brushes or passages of the standard brushes is being used. In the same test conditions, results obtained indicate that the efficacy of the brushing procedure using 2.8 mm ball brushes regarding reduction of the number of viable bacteria is statistically more effective than the standard brushing procedure. VIII : STATEMENT OF GOOD LABORATORY PRACTICE: The study was conducted according to NF EN ISO/CEN (2005) General requirements for the competence of testing and calibration laboratories. The Quality Assurance Unit (QAU) has reviewed this report and determined it accurately describes the procedures used and that the results and conclusions herein accurately reflect the raw data from the study. Applicable Standard Operating Procedures and Good Laboratory Practice were followed in this study. The original records of this report, the notebooks, protocol, and final study report are stored in the archives of Biotech-Germande "547.CBC.07". Audrey BANCOD Signature Date 24/10/2007 Test manager Christine AH-DIP Signature Date 24/10/2007 Quality Assurance Unit manager Marlène RICHARD Signature Date 24/10/2007 Study manager Lionel PINEAU Signature Date 24/10/2007 Laboratory director Parc Scientifique de Luminy 163 Avenue de Luminy case MARSEILLE cedex 9 14/14