Transcript A Brief History of Medical Disasters

Contamination Control
in Practice
Tim Sizer
University of Leeds
Cleaning and Disinfection
• Never separate
• Cleaning always precedes disinfection
• Effective cleaning and disinfection is essential
to remove or reduce contamination
» particulates
» microorganisms
» protective films
» chemicals
» static electricity
Products
People / operators
Air supply
Packaging
Paper
Equipment
• Necessary to satisfy regulatory requirements and
written standards
WHY WORRY ABOUT CONTAMINATION?
• We have to comply with GMP
“…cleaned thoroughly in accordance
with a written programme”
“Sanitation”
The Quality Assurance of Aseptic
Preparation Services Chapter 12. Cleaning:
states:
12.1.2 “Clean areas must be regularly cleaned
…. according to a written procedure.
A log should be kept of the areas cleaned,
indicating the agents used.”
Accidental drug spills contribute to
surface contamination
• Case 1
– Floor contamination with fluorouracil and
ifosfamide after the renovation and
cleaning of a pharmacy.
– persistent contamination after two months
of construction when the pharmacy area
was not operational
Connor, Anderson, Sessink, & Spivey. (2002)
• Case 2
– Clean, but used BSC installed in a new prep
room.
– Found contamination of cabinet and direct
surroundings after installation
Vandenbroucke & Robays (2001)
Meningitis Due to Iatrogenic BCG Infection in Two
Immunocompromised Children
Stone, Vannier, et al N. England J. Med 1995; 333-561-563.
• 2 children (ages 3 & 5) with leukemia  BCGassociated meningitis.
• Neither was receiving BCG, neither had hx of BCG
vaccination.
• Infections may be due to accidental inoculation of
BCG during admin of intrathecal methotrexate.
• “The intrathecal chemotherapy … may have been
accidentally contaminated during the preparation…..”
• Failed to identify how contamination occurred
• Surface samples failed to grow any mycobacteria
People cause contamination
People are responsible for 80% of particulates in
clean rooms
A fully-clothed adult emits 9 x 106 particles in the
size range 0.5 to 100 micron (µm) every minute
Sitting quietly
100,000
Moving
1,000,000
particles shed per minute
Walking
5,000,000
Airborne Skin Squames
100 to 5,000 cfu every minute !
14 μm
…
……
2m
7 minutes
Opening your mouth causes contamination
Normal
Breathing
Normal Talking > 1-2 m/s
0.6 - 1.0 metres
Coughing
>2 m/s
> 3 m/s
1.5 - 2.0 metres
Sneezing > 7 m/s
(200 mph throat velocity! = 100 m/s)
Coughing and sneezing can cause an
alarming increase in contamination,
because not only are particles being
generated, but they are mixed with liquid
droplets in aerosol as well.
3 to 5
metres
In pharmaceutical environments
contamination is controlled:
• partly by design & construction
• partly by behaviour
Storage Areas
Risk reduction is achieved through a
continuum of tasks and activities
Starts with goods receipt and
continues through to administration
• Items intended for aseptic preparation
•
•
•
•
•
must be handled and stored
appropriately
Dust free environments
or protected
Minimal packaging
Appropriate handling
e.g. trays / gloves / bags
Appropriate clothing
and behaviour
Caution: Light Protection!
Storage - refrigeration
 limits microbial growth
 increases viscosity
 slows degradation
Problems
 Cleaning issues
 Unreliability
 Fluctuations in temperature
 Needs monitoring at all times
Cleaning Materials & Equipment
Nothing should be taken into the cleanroom
that will increase the particulate level or
add contamination to the environment.
All cleaning equipment brought into the
cleanroom must be
spotlessly clean
Appropriate clothing must
be worn
Make-up must not be worn
Paper of all types must be
minimised
Optimum Techniques
• Ensure thorough & complete wetting
• Wiping essential to remove residues &
biofilm
• Using moist wipes
– Dry wipes more likely to shed bits, generate
static
– Wet wipes likely to leave & spread residues
– Damp wipes
– minimise shedding
– absorb liquids into fabric
– lifting and removing soiling
Item Transfer - Spraying-In
•
Wear  gloves for spraying
–
–
•
Wear dedicated clothing
for spraying
–
•
Gloves prevent hands
contaminating items with
microbes, chemicals and
organic matter
They protect operators from
the same things
Work in spraying booths with
fume extract or drip trays
Use correct technique
Item Transfer - Spraying-In
• Aerosol is very important (droplet size)
- 2 reasons
•
•
•
• Wet all surfaces properly!
• Labels are high risk – give particular attention
• Wipe stage is very important
• Attention to labels – high risk
Wipe stage is very important
(QA of Aseptic Services - 4th Edn. 2005)
• Wiping to remove spores
• At least 2 decontamination stages
(one to include wiping)
• Spray  Wipe  Spray
• systematically wipe from the
cleanest end to the dirtiest i.e. from
top to bottom of a bottle
• Use a fresh surface of the swab each
time it comes into contact with item
being disinfected
• The swab should then be discarded
Contact Time
• Surface drying time must be considered
This will be related to the ventilation system
• Disinfectant must stay in contact for
sufficient time – to enable penetration
• Disinfectant must be active during drying
time
• Varies according to disinfectant
• alcohols
- very rapid action
• hypochlorites - fast
• phenolics
- slower
• Varies according to nature of contaminants
Common Myths
• “Disinfectants kill all known
germs….dead!”
• “Disinfectants will solve all our
cleaning problems”
• “We don’t worry about cleaning,
we disinfect”
Cleaning validation is
the determination of the efficacy of cleaning
procedures used in production premises
or on equipment
Objective:
to show that after cleaning, the production
environment & equipment return to original
state of microbiological and chemical
cleanliness.
Documented evidence that the cleaning
procedure will reduce contamination
to an acceptable level
Validation enables routine monitoring to be
reduced to a minimum
Conclusion
• CLEANING IS IMPORTANT
- it saves lives
• It must be done well using
– trained, competent staff
(who are adequately supervised
and undergo regular validations)
– standardised, validated procedures
• It must be documented
• It must be monitored