Cleaning and Disinfecting the Clean Room

Theory of Viable Organism Control and Application Techniques

Kenneth S. Latta, BS, RPh, FIACP, FACASenior Associate

Gates Healthcare Associates, Inc.(Permission Granted To Cleanroom Connection To Use)

Learning Objectives

At the conclusion of this program, the participating pharmacist or technician will be able to:

• Recognize the possible source of microbial contaminates.

• Recognize the difference between the various disinfectants and their class.

• Identify and be aware of the importance of the tools used to apply the cleaning and disinfecting solutions.

People as a Source of Contamination

• 100,000 particles/cu ft/min – Person sitting motionless

• 2,500,000 particles/cu ft/min– Person sitting down or standing up

• 10,000,000 particles/cu ft/min – Person walking

• Billions of particles/cu ft/min – Open, non-airlocked door

• Think “Pigpen” from Charlie Brown comics• A gowned body still creates particles

Cleaning vs Sanitization• Cleaning

– Removes contamination from the surface • Sanitization

– Attempts to destroy viable cells on the surface• Akin to Brushing Teeth versus using Mouthwash• Must remove residue in order to allow the sanitizers to

be effective• Cleaning prepares a surface for disinfection

Becker J Cleanroom Cleaning vs Disinfection Controlled Environments V12 (2) 2009 pg 9-13

Cleaning

• Remove particulates, microbes, and residue.• Requires a non-destructive mechanical action be applied

to loosen and remove organic and inorganic residue from the area.

• Loosened and rinsed to the floor. • Subsequently, the dirtied solution on the floor is collected

and removed via lint-free wipes and cleanroom mops.• Ensure that cleaning solution does not become dirty and

is changed if necessary

Becker J Cleanroom Cleaning vs Disinfection Controlled Environments V12 (2) 2009 pg 9-13

Disinfection

• Saturation and penetration of the cell wall of an organism by a chemical agent

• Contact time – organism must remain wetted for specific time by agent in order to kill

• Depends upon temperature, surface, and disburden of the surface, existent soil load, concentration of the chemical agent, and pH.

• Keeping the surface wetted for five to ten minutes.

Becker J Cleanroom Cleaning vs Disinfection Controlled Environments V12 (2) 2009 pg 9-13

Likely Viable Organisms To be FoundListed from Most to Least Resistant to Disinfectants

• Prions – Type of infectious organism composed only of proteins– Extremely resistant to most chemicals

• Bacterial endospores – Thick-walled dormant form of some bacteria. – More resistant than vegetative bacteria to chemicals,

UV light, drying, and heat

CAG-004-2007 CETA Application Guide for the use of Surface Decontaminants in Biosafety Cabinets

Likely Viable Organisms To be FoundListed from Most to Least Resistant to Disinfectants

• Protozoan cysts (oocysts)– Cryptosporidium and Giardia are two genera of

protozoa that infect the intestinal epithelial cells.– Shed in the feces as resistant cyst (oocyst)– Resistant to many disinfectants

• Mycobacteria– Genus of bacteria that contains higher concentrations

of lipids (fats) in their cell wall– Makes them more resistant to many disinfectants– Notorious member of this genus is M Tuberculosis

CAG-004-2007 CETA Application Guide for the use of Surface Decontaminants in Biosafety Cabinets

Likely Viable Organisms To be FoundListed from Most to Least Resistant to Disinfectants

• Non-Enveloped (naked) viruses– Composed of a protein coat and genetic material such as

Adenovirus or Polio– These viruses are generally more resistant to disinfectants

& desiccation than those with lipid envelope• Fungi & Fungal Spores

– Plant –like organisms that lack chlorophyll & photosynthesis

– Examples: mushrooms, yeast or filamentous mold– Many generate spores which are not as resistant as

bacterial endospores

CAG-004-2007 CETA Application Guide for the use of Surface Decontaminants in Biosafety Cabinets

Likely Viable Organisms To be FoundListed from Most to Least Resistant to Disinfectants

• Vegetative Bacteria– Metabolically active bacteria– Major classification of bacteria based on cell wall structure– Gram positive & negative are Identified by staining– Cell walls affect sensitivity to disinfectants with gram negative

slightly more resistant to disinfectants• Enveloped viruses

– Lipid membrane around protein coat (HIV or Influenza)– Less resistant to disinfectants & desiccation than naked virus– Destroy lipid membrane and the virus is no longer infectious

CAG-004-2007 CETA Application Guide for the use of Surface Decontaminants in Biosafety Cabinets

Likely Viable Organisms To be FoundListed from Most to Least Resistant to Disinfectants

• Prions• Coccidia (Cryptosporidium)• Mycobacteria (M Tuberculosis)• Cysts (Giardia)• Small Non-Enveloped

Viruses (Polio)• Trophozoites

(Acanthamoeba)

• Gram-Negative Bacteria- non-sporulating (Pseudomonas)

• Fungi (Candida, Aspergillus) • Large Non-Enveloped Viruses

(Entero-, Adeno-)• Gram-Positive Bacteria (S.

Aureus, Enteroccocus)• Lipid Enveloped Viruses (HIV,

HBV)

McDonnell et al Antiseptics and Disinfectants: Activity, Action, and Resistance Clin . Microbiol. Rev. 1999 12(1) 147-81

Classes of Disinfectants

• Sterilants – Can kill all microbes, spores and viruses, given

enough time.– Glutaraldehyde, Hydrogen Peroxide/peracetic Acid,

Chlorine Dioxide, Acidified Sodium Hypochlorite, Vaporized Hydrogen Peroxide

• High-Level Disinfectants – Kill all viruses and vegetative cells, but they may not

kill endospores reliably– Sodium Hypochlorite, Hydrogen Peroxide

Classes of Cleaners

• Intermediate-Level disinfectants – Destroy all vegetative cells including Mycobacteria,

fungi, and most, but not all viruses– They can not kill Endospores– Isopropyl Alcohol, Phenolics

• Low-Level (General Purpose) disinfectants– Destroy vegetative bacteria, except mycobacteria,

fungi and non-enveloped viruses– Quaternary Ammoniums, Ethanol

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