Chapter 10: Asepsis

Virulence

(The extent of dangerousness of pathogens.) pathogens structures and functions can promote the dangerousness of pathogens. For instance, some of them have fimbriae, tiny hairs used to attach themselves to the host's tissue to avoid expulsion. Fimbriae prevent pathogens that reach the bladder from being eliminated during urination.

Aspects that Increase A Pathogen's Virulence

1. Fimbriae-Tiny hairs used to attach themselves to the hos'ts tissue to avoid expulsion. 2. Flagella- long tails that promote motility to reach a site less hostile to survival. 3. Toxins

Chain of Infection-6

1. Infectious Agent 2. Reservoir for growth and reproduction 3. Exit route from the reservoir 4. means of transmission 5. portal of entry 6. Susceptible host

Sterile Field

Means a work area free of microorganisms. It is formed using the inner surface of a cloth or paper wrapper that holds sterile items. The filed enlarges the area where sterile equipment or supplies are placed.

Hand Antisepsis

Means the removal and destruction of transient microorganisms without soap and water. It involves products such as alcohol-based liquids, thick gels, and foams. Alcohol-based hand rubs are not substitutes for hand washing in ALL SITUATIONS.

Medical Asepsis

Means those practices that confine or reduce the numbers of microorganisms. Also called clean technique, it involves measures that interfere with the chain of infection in various ways.

Concurrent Disinfection

Measures that keep the client environment clean on a daily basis which include: 1. Clean less soiled areas before grossly dirty ones 2. they wet mop floors and damp dust furniture to avoid dispersing microorganisms on dust particles and air currents. 3. Discard solutions used for mopping in a flushable hopper. 4. They never place clean items on the floor.

When Microorganisms Invade

One of 3 things occurs: 1. The body's immune system eliminates them, 2. They reside within the body without causing disease, 3. Or they cause an infection or an infectious disease.

Rickettsiae

Resemble bacteria; like viruses however, they cannot survive outside another living species. Consequently an intermediate life-form, such as fleas, ticks, lice, or mites, transmits rickettsial diseases to humans. Ex. Tiny deer ticks transmit Lyme disease. Note: Carried by vectors like ticks, mosquitos, etc.

Bacteria Shapes-Bacilli

Rod shaped

Protozoans

Single celled animals classified according to their ability to move. Some use amboid motion by which they extend their cell walls and their intracellular contents flow forward. Others move by cilia (hairlike projections) or flagella (whiplike appendages). Some cannot move independently at all.

Bacteria

Single celled microorganisms. They appear in various shapes: cocci=round, bacilli-rod shaped, spirochetes=spiral.

Anti-Infective Drugs

Two groups of drugs used most often to combat infections are antibacterials and antivirals.

Lipping a Container

When a nurse pours and discards a small amount of the sterile solution to wash away air borne contaminants from the mouth of the container.

Chain of Infection-Portal of Entry

Where microorganisms find their way onto or into a new host, thus facilitating their relocation. Most common ports of entry is an opening on the skin or mucous membranes. Microorganisms also can be inhaled , swallowed, introduced into the blood, or transferred into body tissues or cavities through unclean hands or contaminated medical equipment.

Antiseptics

also know as bacteriostatic agents, inhibit the growth of, BUT DO NOT KILL, microorganisms. Ex. Alcohol. Antiseptics are generally applied to the skin or mucous membranes. Some are also used as cleansing agents.

Disinfectants

called germicides and bactericides, destroy ACTIVE microorganisms but not spores. Ex. Phenol, household bleach, and formaldehyde. Disinfectants are rarely applied to the skin because they are very strong. Usually used to kill and remove microorganisms from equipment, walls, and floors.

Sterilization

consists of physical and chemical techniques that DESTROY all microorganisms, including spores.

Hand Washing

is Medical aseptic practice that involves cleaning the hands with soap, water, and friction to mechanically remove dirt and organic substances. It is the preferred method of hand hygiene when the hands are visibly dirty.

Peracetic Acid

is a liquid sterilizing agent which is a combination of acetic acid and and hydrogen peroxide. Peracetic acid is the most effective agent against bacteria, viruses, yeasts, and molds. It steriizes equipment quickly, is effective in the presence of organic material such as blood and stool, and decomposes into environmentally safe byproducts.

Nonpathogens

live abudantly and perpetually on and within the human body, which is their host. Found in skin, nose, mouth, throat, lower urethra, and intestines. Most exist in the lower intestine.

Microorganisms

living animals or plants visible only through a microscope, commonly called microbes or germs. Microorganisms are present everywhere, air, soil, water, on and within virtually everything and everyone.

Surgical Hand Antisepsis

previously referred to as a surgical scrub, is a medically aseptic hand-hygiene procedure that is performed before donning sterile gloves and garments when the nurse is involved in an operative or obstetric procedure.

Bacteria Shapes-Cocci

round

Bacteria Shapes-Spirochetes

spiral

Sterile Solutions

such as normal saline, come in various volumes. Note: Before using a sterile solution, the nurse pours and discards a small amount to wash away air borne contaminants from the mouth of the container. This is called 'lipping' the container.

Chain of Infection definition

the sequence that enables the spread of disease producing microorganisms must be in place if pathogens are to be transmitted from one location or person to another.

Vehicle Transmission

transferof microorganisms present on or in contaminated items such as food, water, medications, devices, and equipment. Ex. Consumption of water contaminated with microorganisms.

Radiation-Ultraviolet

ultraviolet radiation can kill bacteria, especially the organism that trasmits TB. THis is generally combined with other aseptic methods, however, its efficacy depends on circulating organismss by air currents from lower areas of a room to wall or ceiling mounted units, etc.

Principles of Asepsis

1. Microorganisms exist everywhere except on sterilized equipment 2. Frequent hand hygiene and maintaining intact skin are the best methods for reducing the transmission of microogansims. 3. Blood, body fluids, cells, and tissues are considered major reservoirs of microorganisms. 4. PPE such as gloves, gowns, masks, goggles, and hair and shoe covers serve as a barrier to microbial transmission. 5. A clean environment reduces microorganisms. 6. Certain areas---the floor, toilets, and the insides of sinks--are more contaminated than others. 7. Cleaning should be done from cleaner to dirtier areas.

Hand Washing Removes: (2)

1. Resident Microorganisms 2. Transient Microorganisms

Three Types of Fungi (Mycotic) Infections-

1. Superficial 2. Intermediate 3. Systematic.

What Influences Whether an Infection Develops Include:

1. Type and Number of Microorganisms, 2. The characteristics of the microorganism (Such as its Virulence) 3. The person's state of health.

Biologic Defense Mechanisms

Anatomic or physiologic methods that stop microorganisms from causing an infectious disorder. These often prevent microorganisms from producing infections. 2 types of biologic defense mechanisms are mechanical and chemical.

Carriers

Asyptomatic clients or animals that harboor pathogens but do not show evidence of an infectious dieasease are known as carriers.

Survival of Microorganisms-Spore

Many pathogens have mutated to adapt to hostile environments. Example of biologic adaptation is the ability of some microorganisms to form spores which is a temporarily inactive microbial life form that can resist heat and destructive chemicals and can survive without moisture. Spores are more difficult to destroy than their more biologically active counterparts. When conditions are favorable spores can reactivate and reproduce.

Contact Transmission-Direct Contact

Actual physical transfer from one infected person to another(body surface to body surface contact). ex. Sexual intercourse with an infected person.

Intermediate Fungal Infections

Affect subcutaneous tissues such as fungal granuloma (a inflammatory lesion under the skin) .

Superficial Fungal Infections

Affect the skin, mucous membranes, hair, and nails. Ex. Tinea corporis (ringworm), tinea pedis (athlete's foot), and candidiasis (yeast infection that infects mucous membranes in the mouth and vagina).

Nonpathogens and Pathogens Include:

Bacteria, Viruses, fungi, ricksettsiae, protozoans, mycoplasmas, helminths, and prions.

Principles of Surgical Asepsis

Based on the premise that once equipment and areas are free of microorganisms, they can remain in that state if contamination is prevented.

CHemical Sterilization

Both gas and liquid chemicals are used tosterilize invasive equipment. Ex. Peracetic acid andperformic acid.

Physical Sterlization-Boiling Water

COnvenient way to sterilize items used in the home. Must be boiled for 15 minutes at 212 F or 100 C.

Antibacterials

Chemical actions of antibacterials (antibiotics and sulfonamides) alter the metabolic processes of bacteria but viruses. They damage or destory bacterial cell walls or the mechanisms that bacteria need to reproduce. When used the intent is to kill or control pathogens. Note: these drugs have the capacity to similarly affect normal nonpathogenic bacteria. ie. Superbugs.

Antimicrobial Agents

Chemicals that destory or suppress the growth of infectious microorganisms. Some antimicrobial agents are used to clean equipment, surfaces, and inanimate objects. Ex. are antiseptics, disinfectants, and anti-infective drugs.

Survival of Microorganisms

Conditions that promote survival are warmth, darkness, oxygen, water, and nourishment. Humans offer all these and so are optimal hosts for supporting the growth and reproduction of microorganisms.

Contact Transmission-Indirect Contact

Contact between a susceptible person and a contaminated object. Ex. Use of a containated surgical instrument

Mycoplasmas

Lack a cell wall. they are referred to as pleomorphic because they assume various shapes. Mycoplasmas are similar, but not related to bacteria. Primarily they infect the surface lining of the respiratory, genitourinary and gastrointestinal tracts.

Chemical Defense Mechanisms

Destroy or incapacitate microorganisms through natural biologic substances. Ex. Lysozyme, and enzyme found in tears and other secretions can dissolve the cell wall of some microorganisms. Gastric acid creates and inhospitable microbial environment. Antibodies, etc.

Ethylene Oxide Gas

Destroys a broad spectrum of microorganisms, including spores and viruses, when contaminated items are exposed for 3 hours at 86 F (30 C) Gassed items must be aired for 5 days at room temperature or 8 hours at 248 F(120 C) to remove traces of gas, which can cause chemical burns.

Antiviral Agents

Developed more recently, most likely in response to the rising incidence of influenza and blood borne viral diseases such as AIDS. antivirals DO NOT destroy the infecting viruses, rather, they control viral replication (copying) or their release from the infected cells. The virus remains alive and can potentially cause reactivation of the illness. Ex. Chicken pox reborn as shingles.

Physical Sterilization-DRy Heat

Dry heat, or hot air steriliaztion is similar to baking items in an oven. To destory microorganisms with dry heat, temperatures of 330-340F or 165C to 170 C. Good technique forsterilization sharp instruments and reusable syringes because moist heat damages cutting edges and the ground surfaces of glass.

Physical Sterilization-Steam Under Pressure

Ex. Autoclave. Steam under pressure isthemost dependable method for destorying all forms of organisms and spores.

Anaerobic Bacteria

Exist without oxygen.

Resident Microorganisms

Generally nonpathogens constantly present on the skin.

What is the Single Most Effective Way to Prevent Infections?

Hand Hygiene.

Pathogens

Have a high potential for causing infectious Communicable diseases/ Contagious Diseases, and Community-Acquired Infections. Ex. Streptococcal sore throat, STIs, TB, and AIDS.

Chain of Infection-Means of Transmission

How infectious microorganisms move to another location. Microorganisms are transmitted by one of five routes: 1. contact, 2. droplet 3. airborne 4. vehicle 5. Vector

Chain of Infections-Susceptible Host

Last link in the chain of infection , is one whose biologic defense mechanisms are weakened in some way. Particularly susceptible clients include those who: 1. are burn victims 2. have suffered major trauma 3. require invasive procedures such as endoscopy 4. Need indwelling equipment such as a urinary catheter. 5. Infected with HIV

Sterile techniques

Include practices that avoid contaminating microbe free items. Both Surgical Asepsis and sterile techniques begin with the process of sterilization

Fungi

Include yeasts and molds. Only a few types of fungi produce infectious dieases in humans.

Systemic Fungal Infection

Infect deep tissues and organs, such as histoplasmosis ( also called 'cavers lung' or 'cave disease') of the lungs. Histoplasmosis is most often contracted after breathing in microscopic specs of animal feces.

Infectious Agents-Opportunistic Infections

Infectious disorders among people with compromised health.

Helminths

Infectious worms, some of which are microscopic. They are classified into 3 major groups: 1. Nematodes (roundworms) 2. Cestodes (tapeworms) 3. trematodes (Flukes) Note: some helminths enter the body in egg stage, while others spend the larval stage in an intermediate life form before finding their way into humans. ex. Pork

Reservoir

Is a place where microbes grow and reproduce, providing a haven for their survival. Microbes thrive in reservoirs such as tissues within the superficial crevices inside the lower digestive tract, and in nasal passages. Some grow abundantly in stagnant water, in uncooked food, and on used utensils or equipment.

Prions

Is a protein containing no nucleic acid. Scientists speculate that mutated prions are the cause of Alzheimers. Note: humans have normal prions in their brains, prions are mutated forms that can cause transmissible spongiform encephalopathies.

Chain of Infection-Exit route

Is how microorganisms excape from their original reservoir and move about. Ex. When they are displaced by handling or touching objects or whenever blood, body fluids, secretions, and excretions are released.

Terminal Disinfection

Is more thorough than concurrent disinfection and consists of measures used to clean a client's environment after discharge. It includes scrubbing the mattress surface and the insides of drawers and bedside stands.

Aerobic Bacteria

Require oxygen to live

Physical Sterilization - Free Flowing Steam

Method in which items are exposed to the heated bapor that escapes from boiling water. Same time and temp, as boiling water. Less reliable.

PHysical Sterilization

Microorganisms and spores are destroyed physically through radiation or heat, boiling water, free flowing steam, dry heat, and steam under pressure.

Types of Microorganisms

Microorganisms are divided into two main groups: 1. Nonpathogens (or normal flora) 2. Pathogens ( microorganisms that cause illness).

Airborne Transmission

Movement of microorganisms attached to evaporated water droplets or dust particles that have been suspended and carried over distances greater than 3 ft. Ex. Viral weapon

Nonpathogens Assume On of Two Relationships with Their Human Host:

Mutually beneficial or neither harmful nor helping the host. -They inhibit pathogenic growth and reproduction by competing for nutrients, vying for space or producing substances that interfere with the pathogens

Fomites

Nonliving reservoirs.

Nosocomial Infections

Nurses mus understand and practice methods to prevent nosocomial infections which are infections acquired while a person is receiving care in a health care agency. Note: Noso prefix means: disease comial suffix means: to take care of.

Transient microorganisms

Pathogens picked up during brief contact with contaminated reservoirs.

Mechanical biologic defense mechanisms

Physical barriers hat prevent microorganisms from entering the body or that expel them before they multiply. Ex. Intact skin and mucous membranes, reflexes such as sneezing and coughing, and infection fighting blood cells called "phagocytes" or 'Macrophages'.

Hand Hygiene

Refers to removing surface contaminants on the skin by either hand washing or hand antisepsis.

Asepsis

Refers to those practices that decrease or eliminate infectious agents, their reservoirs, and vehicles for transmission. Health care professionals use medical and surgical asepsis to accomplish this goal.

Viral Load

The number of viral copies.

Viruses

The smallest microorganisms known to cause infectious diseases, are visible only through an electron microscope. They are filterable, meaning that they can pass through very small barriers. -Viruses are unique because they do not possess the genetic information necessary to reproduce; they require metabolic and reproductive materials from other living species. (RNA) -Virals can remain dormant in a host and reactivate sporadically, ex. herpes simplex virus (causes cold sores) to repeatedly flare up years after an initial infection.

Surgical Asepsis

Those measures that render supplies and equipment totally free of microorganisms.

What is the goal of antiviral therapy

To limit the viral load.

Vector Transmission

Transfer of microorganisms from an infected animal carrier. Ex. Diseases spread by mosquitos, fleas, ticks, or rats.

Droplet Transmission

Transfer of moist particles from an infected person who is within a radius of 3 ft. Ex. Inhalation of droplets released during sneezing, coughing, or talking.