Quiz 3: The Autoclave and Disinfectants

Disinfectants: Listerine

- An antiseptic mouth rinse = broad-spectrum antimicrobial - Kills bacteria associated with plaque and gingivitis by disrupting the bacterial cell wall. - Kills both gram + and gram - organisms - mouth rinses contain alcohol (21.6% in flavored versions to 26.9% in the original) - alcohol used in listerine is pharmaceutical-grade alcohol, and is necessary to solubilize the active essential oils ingredients (eucalyptol, thymol, methyl salicylate, menthol) that kill bacteria that cause plaque and gingivitis. - alcohol in listerine (ethanol) serves as the best carrier to help the 4 essential oils quickly penetrate the plaque. - According to the manufacturer, no other mouthwash for everyday use has been proven more effective against plaque biofilm than listerine.

When running an endospore control of autoclaving technique, why is one endospore preparation incubated without heating?

- Autoclave sterilization units should be tested weekly to determine the function and efficiency of the unit - A biological test containing two test strips is used during this process. - Both strips contain highly resistant spores from the same lot. - There is the test, the one that gets ran through the sterilizer unit, and the control, the one that remains in the envelope. - The control is used to determine if the unit has destroyed the spore effectively. - Inability to destroy the spore indicates a problem with the machine

Disinfectants: 4% Chlorhexidine gluconate (biguanides)

- Broad-spectrum activity - Disrupt bacterial cell membranes; not sporicidal - Chlorhexidine is frequently used for microbial control on skin and mucous membranes; combined with detergent or alcohol, it is used for surgical scrubs and preoperative skin preparation in patients

Disinfectants: Clorox (halogens)

- Chlorine (Cl2 gas) - Germicidal action is caused by hypochlorous acid (HOCl) that forms when chlorine is added to water - Strong oxidizing agent that denatures enzymes - Compressed chlorine gas used to disinfect municipal drinking water, swimming pools, and sewage - Sodium hypochlorite is used as household bleach (Clorox) - Chloramines (chlorine and ammonia) also used in municipal drinking water; used to sanitize glassware and eating utensils; stable compounds that release chlorine over long periods

Disinfectants: 3% H2O2 (Peroxygens)

- Hydrogen peroxide = oxidizing agent (releases free hydroxyl radical) - Bactericidal with wide spectrum of action - Clinically used to cleanse wounds; also used to disinfect contact lenses - Reacts with catalase to form harmless water and oxygen (bubbles)

Disinfectants: 10% Betadine (halogens)

- Iodine (I2 gas) - Alters protein synthesis and membranes; oxidizes cell constituents - Tinctures: In aqueous alcohol - Iodophors: Combo of iodine and an organic compound - iodine is released slowly (don't stain and less irritating than iodine alone). - Most common iodophor is Betadine (povidone- iodine). Povidone is a surface-active iodophor that improves the wetting action and serves as a free reservoir of free iodine. - Iodine is used mainly for skin disinfection and wound treatment and camping water treatment.

What characteristics of Bacillus stearothermophilus make it valuable for use as a control organism for heat-sterilization techniques? Explain

- It is most resistant to the moist heat. - So if sterilization technique is able to destroy its cells it means that it would kill any other cell with a lot more surety.

Disinfectants: Lysol

- Phenol: rarely used as a antiseptic/disinfectant - Phenolics = derivatives of phenol. They are less irritating and have greater antimicrobial activity - Phenolics denature proteins and injure plasma membranes; also effective on mycobacteria - Remain active in presence of organic compounds, are stable, and persist after application - Cresol (o-phenylphenol) = main ingredient in most lysol formulations (good surface disinfectants)

Why is it necessary to use bacteriologic controls to monitor heat-sterilization techniques?

- Such preparations contain viable endospores dried on paper strips or suspended in nutrient broth within a sealed ampule. - When appropriately placed within an autoclave load, endospores controls can indicate whether the autoclave is operating efficiently and mechanically, that individual item packing is correct, and load arrangement allows sterilization of every item.

UNITED STATES DEPARTMENT OF LABOR OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION (OSHA) states...

- To wear gloves (in addition to hand washing) - Gloves = important role in reducing the risks of transmission of microorganisms

What is an autoclave?

- it is a steam-pressure sterilizer - steam = the vapor given off by water when it boils at 100 degrees celsius - auto = self; clavis = self locking device

What does an autoclave look like?

- large, heavy-walled chamber with steam inlet and air outlet - can be sealed to force steam accumulation

Essentially, what is the main role of an autoclave?

- removes microorganisms and spores using high pressure and high temperature steam sterilization - no contamination/sterilize contaminated material

What are chemicals that kill microbes called?

-cidal agents aka bactericidal (kills bacteria), fungicidal (kills fungus), and viricidal agents (kills viruses)

What are agents that do not kill but only inhibit growth called?

-static agents aka bacteriostatic, fungistatic, and viristatic agents

Two essential factors in heat sterilization?

1) temperature 2) time

What are the principles of effective chemical disinfection?

1. Concentration of disinfectant 2. Nature of material being disinfected (organic matter, biofilms) 3. pH and temperature 4. Contact between disinfectant and area to be disinfected 5. Time of exposure 6. Number of microbes 7. Microbial characteristics

Why are gloves worn in hospitals?

1. Gloves are worn to provide a protective barrier and to prevent gross contamination of the hands when touching blood, body fluids, secretions, excretions, mucous membranes, and non-intact skin. 2. Gloves are worn to reduce the likelihood that microorganisms present on the hands of personnel will be transmitted to patients during invasive or other patient-care procedures that involve touching a patient's mucous membranes and non-intact skin. 3. Gloves are worn to reduce the likelihood that hands of personnel contaminated with microorganisms from a patient or object can transmit these microorganisms to another patient. In this situation, gloves must be changed between patient contacts and hands washed after gloves are removed. Wearing gloves does not replace the need for hand washing, because gloves may have small, in-apparent defects or may be torn during use, and hands can become contaminated during removal of gloves. Failure to change gloves between patient contacts is an infection control hazard.

What are four chemical antimicrobial agents?

1. Sterilant 2. Sanitizer 3. Antiseptic 4. Disinfectant

Process of B. stearothermophilus endospores placed into autoclave:

1. Strips with B. stearothermophilus endospores are placed into autoclave with the material to be sterilized. 2. After autoclave cycle is completed, each strip is placed into a broth and incubated at 56 degrees celsius. 3. Second control strip has NOT been autoclaved but is also incubated in broth at same time 3. RESULTS: - endospores on the control strip have germinated - growing vegetative cells have made the broth both turbid and changed the color of the pH indicator in the broth - autoclaved endospores have been sterilized so clear/original color

Betadine Solution

Active ingredient: Povidone-iodine, 10% (1% available iodine) Purpose: antiseptic Uses: - for preparation of the skin prior to surgery; patient pre-operative skin preparation - helps reduce bacteria that potentially can cause skin infection Warnings: - For external use only - Do not use if you are allergic to povidone-iodine or any other ingredients in this preparation. When using this product: - Prolonged exposure to wet solution may cause irritation or, rarely, severe skin reactions. - In pre-operative prepping, avoid "pooling" beneath the patient. Stop use and ask a doctor if irritation, sensitization, or allergic reaction occurs and lasts for 72 hours. - Keep out of reach of children. If swallowed, get medical help or contact a Poison Control Center right away. Directions: 1. Clean the operative site prior to surgery 2. Apply product and allow to dry 3. May be covered with a bandage

Excelle

Active ingredient: chlorhexidine gluconate 4% solution Purposes: surgical hand scrub; healthcare personnel handwash; patient preoperative skin preparation; skin wound and general skin cleansing Uses: - surgical hand scrub: significantly reduces the number of microorganisms on the hands and forearms prior to surgery or patient care - healthcare personnel hand-wash: helps reduce bacteria that potentially can cause disease - patient preoperative skin preparation: preparation of the patient's skin prior to surgery - skin wound and general skin cleansing Warnings: - For external use only - Do not use: If you are allergic to chlorhexidine gluconate or any other ingredients; In contact with meninges; In the genital area; As a preoperative skin preparation of the head or face

What is a sterilant?

An agent that destroys all forms of microbial life

What is a disinfectant?

An agent that kills or inhibits growth of pathogenic microbes and is used only on inanimate objects

What is an antiseptic?

An agent that kills or inhibits growth of pathogenic microbes and is sufficiently nontoxic to be applied to living tissue

What is a sanitizer?

An agent that reduces, but may not eliminate, microbial numbers to a safe level

What is the difference between an autoclave and dry-heat oven?

Autoclave - water and steam - sterilization with coagulation of protein - under pressure - less time Dry-heat - no water or steam - sterilization with oxidation - direct flame - more time

Endospores of __________ __________________ are used in testing autoclave operation.

Bacillus stearothermophilus

Why are the endospores of Bacillus stearothermophilus used to test autoclave operation?

Because their endospores are highly resistant to the effects of moist or dry heat.

Disinfectants: 70% alchohol scrub (alcohols)

Ethanol and Isopropanol - Protein denaturation, disrupts membranes, dissolves many lipids - Rapidly evaporates and leaves no residue - Often used as a degerming agent before injections - Optimum concentration of ethanol is 70% (slower evaporation and denaturation requires water); Purell, a hand cleaner, contains 62-65% ethanol combined with skin moisturizers - Isopropanol (rubbing alcohol) less volatile and less expensive

Decreasing order of resistance of microorganisms to chemical biocides:

MOST RESISTANT: - Prions - Bacteria w/ endospores - Mycobacteria - Cysts of protozoa - Vegetative protozoa - Gram - bacteria - Fungi (and fungal spores) - Viruses w/o envelopes - Gram + bacteria - Viruses w/ lipid envelopes LEAST RESISTANT:

What pressure, temperature, and time are used in routine autoclaving?

Pressure: 15 to 20 Lb of steam pressure Temperature: 121 to 125 degrees C (250-256 degrees F) steam temperature Time: 15 to 45 minutes, depending on the nature of the load

Purell Instant Hand Sanitizer

Product Description: Kills 99.99% of the most common germs that may cause illness. Use anytime, anyplace, without water or towels. Leaves hands feeling refreshed without a sticky residue. Active Ingredient: Ethyl Alcohol 65% Antiseptic Uses: for hand-washing to decrease bacteria on the skin; recommended for repeated use Warnings: - For external use only - Flammable, keep away from fire or flame. - Do not use in the eyes. In case of contact, rinse eyes thoroughly with water. - Stop use and ask a doctor if irritation and redness develop and persist for more than 72 hours. - Keep out of reach of children. If swallowed, get medical help or contact a Poison Control Center right away. Directions: 1. Wet hands thoroughly with product. 2. Briskly rub hands together until dry. 3. Supervise children in the use of this product

Would you choose a dry-heat oven, an autoclave or incineration to heat sterilize the following items? State why. Soiled dressings from a surgical wound: Surgical instruments: Clean laboratory glassware: Clean reusable syringes:

Soiled dressings from a surgical wound: Incinerate (no use for these) Surgical instruments: Autoclave (will sterilize the surgical instruments that will be used again) Clean laboratory glassware: Dry-heat oven (cleans the glassware and removes any water residue) Clean reusable syringes: Dry-heat oven (removes any water residue that may affect volume readings)

From class, autoclave results: B. subtilis

Untreated control: - Incubation temp: 35 degrees celsius - Color: yellow (sugar + pH) - Turbidity: medium - Growth: + Autoclaved (treated) control: - Time: 25 min - Temp: 121 degrees celsius - Pressure: 151 lbs - Incubation temp: 35 degrees celsius - Color: red (sugar + pH) - Turbidity: N/A - Growth: -

From class, autoclave results: B. stearothermophilus

Untreated control: - Incubation temp: 56 degrees celsius - Color: yellow (broth) - Turbidity: medium - Growth: + Autoclaved (treated) control: - Time: 15 min - Temp: 121 degrees celsius - Pressure: 151 lbs - Incubation temp: 56 degrees celsius - Color: yellow (broth) - Turbidity: N/A - Growth: -

The ____________ _____ ____ _________ in a heating sterilizing chamber greatly influences the time required to sterilize every item within the load.

nature of the load

What takes longer to sterilize: operating room linen packs or metal surgical instruments?

operating room linens because it requires steam penetration of the thick, bulky, porous articles. Sterilization of metal surgical instruments require steam condensation on the surface, which are quickly raised to sterilizing temperature

In the autoclave, it is the intensity of _____________ _________________ that sterilizes, when it is given time measured according to the nature of the load in the chamber.

steam temperature