# Presentation: 346124

## CDRH - CBER TSE INSTRUMENT DECONTAMINATION PROJECT

- Stanley Brown, Katharine Merritt,
- Terry Woods, Scott McNamee and Deanna Busick
- CDRH/ OST / DMMS & DLS
- David Asher, Kitty Pomeroy, Rolf Taffs
- CBER / OBRR / DETTD
- with funding from
- FDA, Office of Science & Health Coordination
*TSEAC 17 July 03*

## INSTRUMENTS

- Surgical – primarily reusable.
-         but also “Single” Use Devices, SUDs
-      exposed to contaminated human tissues
- tissue processing
-          exposed to animal tissues

## Disclaimer

- The methods used were selected by the research teams, as reasonably inexpensive approaches, within the constraints of the FDA lab facilities and manpower, to:
-        1. provide an understanding of the issues
-        2. examine the feasibility of decontamination protocols recommended by WHO
- These presentations do not constitute regulatory endorsement as methods to validate decontamination protocols.

## WHO  protocols

- autoclave in 1 N NaOH, 121°C, 30 min
- immerse 1 hr in:
-       2a.  1 N NaOH, or
-       2b.  sodium hypochlorite (20,000 ppm Cl)
-         --- then autoclave in water 121°C, 1 hr
- soak in NaOH or Bleach, rinse
-             then steam autoclave, 1 hr
****** all followed by routine (ultrasonic) cleaning,   rinsing,  and sterilization***

## CDC website notes & warnings

- 1.  autoclaving in NaOH
-            can wreck autoclave and operators
- 2b.  soaking in bleach
-           can wreck instruments
- these are based on CDRH studies

## CDRH / OST TSE Decontamination Research

- Issues based on WHO recommendations
-   1. safety of autoclaving in NaOH
-   2. effects of protocols 1 & 2 on instruments
-   3. develop pins as model “instruments”
-   4. Protein & Microbial decontamination

## 1.  Use of Containment Pans and Lids for Autoclaving Caustic Solutions

- Stanley A. Brown, Katharine Merritt
*Am J. Infection Control*
-  31: 257-260, 2003.

## The problem

- WHO method #1:
-  place instruments in 1 N NaOH
-           and autoclave at 121°C.
- Some autoclave manufacturers have said:
-      **“****do that and you have no warranty”**
- Note: must use gravity displacement autoclaves, with liquid (no vacuum) cycles.

## Methods

- A.  1 L of NaOH in a pan & cover
- B.  10 ml NaOH in beaker in a pan & cover
-     1.   Place in table top
-              gravity displacement autoclave
-     2.  repeat 1 hr sterilization cycles
-     3.  measure pH inside and out of pan & lid
-     4.  measure pH of autoclave
-              6 liter water reservoir

##  somepansandlids

## Lid (F) Pan (4), Nalgene Instrument pipet sterilizing panfilled with 1 liter of NaOH

## note gutter drain slot 

##  lid contained inside pan lip

## Lid (D) Pan (2), NaOH in an open beaker in the pan

## Results – autoclaving in NaOH

- No pH changes outside the containment
- Condensate inside container was caustic
- No pH change in water reservoir
- Conclusion:  Autoclaving in NaOH can be done without damage to autoclave interior
- _Caution:_  handle hot caustic with care
- _Note:_ can not be done in Central Services
- _Note:_  may require larger (approved) pans

## The Effects on the instruments of the WHO protocols for TSE  decontamination 

- manuscript in preparation
- Questions:
- 1.  Will protocols cause corrosion?
- Are certain instruments more at risk?
- Does corrosion affect function?

## Methods 

- Bought a bunch of instruments
-         “surgical” from Roboz
-         “Lab” from V W R
-     some “Germany” some “Pakistan”
- Repeated 1 hr cycles:
-         autoclave in 1 N (3.9%) NaOH
-         soak in 1 N (3.9%) NaOH
-         soak in 6% NaOCl  (28,500 ppm Cl)
-         autoclave in water

## 1 hr bleach –vs- 5x autoclave in NaOHNeedle holder carbide jaws

## 1x bleach -vs- 5x autoclave in NaOHneedle holder gold handles

## Germany –vs- Pakistan 5x autoclave in NaOH

## Germany –vs- Pakistan 5x soak in bleach

## Results – Instrument Corrosion

- Autoclaving in NaOH –
-         darkening in some box joints
-         titanium gets very dark
- soaking in NaOH – no changes
- soaking in NaOCl bleach –
-    “good” instruments do OK
-          exception: gold handles, carbide jaws
-     “not so good” corrode, esp. welds & finger rings
- BUT: if it’s going to corrode, it will do it first try;
-         no need for long experiments

## 3.  Pins for “instruments”

- Needed a model “instrument”
-      1. like 25g needle & 1/2 cc syringe
-              used in CBER hamster model
-       2. suspend over 96 well plates
-           for serial dilutions of:
-              bacteria, viruses, brain homogenate
-       3.  autoclavable

## 0.5 x 15 mm SS wire glued in Eppendorf tip

## pins over 96 well plate

## 4.  CDRH PIN STUDY

-      THREE QUESTIONS TO BE ANSWERED
- Will blood and tissue adhere to the pins?
- 2. Will the WHO cleaning protocols remove the blood and tissue?
- 3. Does damage to the instruments affect blood and tissue adherence and cleaning? (Stainless steel vs piano wire)

## blood and tissue adherence

- Pins placed in a rack and immersed in slab of liver for 1 hr, left to dry for 24 hrs
- Pins in rack and into 96 well plate with sheep blood 1 hr, left to dry for 24 hours
-   1. US clean: 60°C,  30 min Klenzyme,  then DW
-   2. autoclave: 1 hr in NaOH, then US clean
-   3. bleach 1 hr: then US clean
-   4. uncleaned controls

## Results – blood and tissue

- Uncleaned controls: More protein adhered to the pins from liver than from blood
- Damaged pins not more adherent
- Repeat exposure and US cleaning (5 times)
-     did not result in increase of protein adherence
- All cleaning protocols removed the protein as detected by Bradfords (less than 1 ul of blood)

## Bacterial Adherence

- Pins placed in a suspension of (*S. epidermidis*)
-        incubated for 24 hours
-        then left to dry
- Then U.S. cleaning or WHO
- Then they were inserted into agar in a test tube and incubated for 24 hours

## Results - Bacterial Adherence (1)

- autoclaving and bleach killed them all
- tried “modified” WHO protocols:
-     Dropped autoclave in 1N NaOH
-     All US cleaning done at room temperature

## Bacteria Results (2)with modified WHO Approach

- Only the pins treated with bleach
-        showed no growth
-                ??? killed or cleaned??
- The other procedures had fewer bacteria
-         than the untreated control,
-         but bacteria were present

## SEM of microbes on uncleaned pin

## CDRH Studies’ Conclusions

- _Some_ WHO protocols can damage
-         _some_ surgical instruments
- The discoloration from NaOH does not seem to impair function or cleaning
- Question: if bacteria were removed in the cleaning protocols?  The final sterilization procedure would kill them.
- Question: can prions be removed – CBER

## Now turn the podium over to Dr. David Asher from CBER