Exam 4 (Ch 20- Promoting Asepsis & Preventing Infection) Flashcards
Virally induced cancers
- Hodgkin’s Disease
- Kaposi’s sacoma
- Cervical cancer
Healthcare-associated infections (HAIs)
Refers to infections associated with healthcare given in any setting (e.g., hospitals, home care, long-term care, and ambulatory settings).
Nosocomial infections
Refers more specifically to hospital-acquired infections.
HAIs aggravate:
existing illness and lengthen recovery time. HAIs seriously increase healthcare costs and patient suffering. It is the 10th leading cause of death in the US
CDC goals for infection control
- Reduce catheter-associated adverse events by 50% in healthcare settigns
- Reduce targeted antimicrobial-resistant bacterial infection by 50%, preventing transmission in health care settings
AHRQ
Agency for Healthcare Research and Quality. Contains links to information, tools, and resources on HAIs.
The Joint Commission
Quality oversight agency. Standards of performance include extensive criteria describing what healthcare organization must do to minimize the risks of infection
QSEN
Quality and Safety Education for Nurses. Group of educators that was formed to address the challenge of preparing nurses with the competencies necessary to improve the quality and safety of their places of work.
Chain of infection
Process by which infections spreads. Made up of 6 links, all of which must be present for the infection to be transmitted form one individual to another.
Normal flora
Microorganisms that are beneficial or even essential for human health and well-being.
Normal flora in the intestine aid in:
Digestion and synthesize vitamin K, and release vitamin b12, thiamine, and riboflavin when they die. They also limit the growth of harmful bacteria by competing with them for available nutrients.
Two types of normal flora:
Transient and resident
Transient flora
normal microbes that a person picks up by coming in contact with objects or another person (e.g., when you touch a soiled dressing). You can remove those with handwashing.
Resident flora
Live deep in skin layers, where they live and multiply harmlessly. They are permanent inhabitants of the skin, and cannot usually be removed with routing hand washing. They are usually not harmful unless they enter the deep tissues or unless the patient is especially vulnerable to disease.
Pathogens
microorganisms capable of causing disease
Infection
successful invasion of the body by a pathogen
Largest groups of pathogenic microorganisms are:
bacteria, viruses, and fungi (which include yeasts and molds)
Less common pathogens are:
protozoa, helminthes (worms), and prions, which are infectious protein particles that cause certain neurological diseases.
Normal flora may become pathogenic if:
disease or injury permit them to enter body regions they do not normally inhabit
Once a pathogen gain entry into a host, 4 factors determine whether the person develops infection:
- Virulence of the organism
- Ability of the organism to survive in the host environment
- Number of organisms (the greater the number, the more likely they are to cause disease)
- Ability of the host’s defenses to prevent infection
Virulence
power to cause disease
6 links of the chain of infection
- Reservoir
- Portal of exit
- Mode of transmission
- Portal of entry
- Susceptible host
- Infectious agent
Reservoir
A source of infection: a place where pathogens survive and multiply. The human body is the most common reservoir for pathogens.
e.g. beside tables, chairs, or equipment. Other surfaces, such as sinks, toilets, bed rails, and bed linens
Carriers
Individuals that have no symptoms of disease, yet they serve as reservoirs and can past he disease to others.
Most pathogens prefer a
warm, moist, dark environment
To live and thrive in human, microbes must:
be able to use the body’s precise balance of food, moisture, nutrients, electrolytes, pH, temperature, and light. Food, water, and soil that provide these conditions may serve as nonliving reservoirs, as well.
Bacteria can rapidly multiply in food left at
room temperature
The bacteria Salmonella enteritis, which causes salmonellosis can multiply in:
raw and undercooked meat and eggs
To prevent the growth of pathogens, many foods are:
cooked at high temps and stored in a cool environment. Alternatively, many foods are prepared with a concentration of solutes that inhibits the growth of pathogenic microbes i.e salting of meats and the production of fruit jellies, jams, and preserves
Pathogens require _____ for survival
moisture
e.g. the moist environment of wounds, the genitourinary tract, the throat and airways
The spore formed by some bacteria allow them to live without ____.
water
e.g. bacillus and clostridium species; both are food-borne diseases
For most pathogens, the ideal temperature is ___
95 degrees F (35 degrees C)
Environments that are either too hot or too cold for a particular species will:
slow its growth or even kill the entire population
The microbes that are pathogenic to humans are so because
they thrive at about the same temperature as the human body; thus, a fever in response to infection can inhibit and even kill invading pathogens
Many bacteria and most protozoa and fungi are ___.
aerobic. They must have oxygen to live and grow.
e. g. yeast Candida albicans causes infection in the oral mucosa (“thrush”) and the vaginal muscosa
Anaerobic organisms
Do not require oxygen for growth and may even be killed in its presence.
e.g. Clostridium tetani, a spore-forming bacterium, which causes tetanus when a spore enters the body through an open wound
To live in humans, pathogens need
the body’s precise balance of moisture, sugars, pH (acidity), and electrolytes.
Most pathogens prefer a pH range of ____ to _____.
5 to 8. therefore, they cannot survive in the highly acidic environment of the stomach.
When patients take antacids, stomach pH increases and removes this defense.
Microbes that have a higher or lower pH and electrolyte concentration than the human body are not
pathogenic to human beings
Microbes grow best in
dark environments (e.g., inside the body, deep in wounds, and under dressings)
Ultraviolet light is sometimes used to
remove pathogens such as staphylococcus, salmonella, and viruses from surgical instruments and other objects. It can also be used to disinfect drinking water in developing countries to prevent diseases such as cholera and typhoid fever
A contained reservoir is only a ___ source of infection.
potential
For infection to spread, a pathogen must
exit the reservoir
Portal of exit
In the case of human or animal reservoirs, the most frequent portal of exit is through body fluids, including blood, mucus, saliva, breast milk, urine, feces, vomitus, semen, or other secretions.
The body’s natural response to foreign materials, including pathogens, is to try to ___ them.
expel.
e.g. If you have a pathogen in the respiratory system, you cough or sneeze. If it’s in the gastrointestinal system, you vomit or experience intestinal cramping and diarrhea.
Cuts, bites, and abrasions provide
an exit for body fluid
Blood and pus seeping from a wound help
transport pathogens away from the broken skin but become a portal by which infection may be transmitted to others.
In healthcare-related infections, puncture sites, drainage tubes, feeding tubes, and intravenous lines commonly serve as
routes for pathogens to exit the body
The most frequent mode of transmission of infection is by
contact, either direct or indirect
Direct contact
involves touching, kissing, or sexual intercourse. Animals commonly transmit infection via scratching and biting as well.
Indirect contact
Involves contact with a fomite
Fomite
a contaminated object that transfers a pathogen
Droplet transmission
Occurs when the pathogen travels in water droplets expelled as an infected person exhales, coughs, sneezes, or talks. It may also occur during suctioning and oral care.
The usual method of droplet transmission
droplet to be inhaled or enter the eye of a susceptible person.
Droplets can travel only ___ from the infectious person
a few feet; within that distance they may readily contaminate fomites that then transmit the organism by contact
Airborne transmission
Occurs with much smaller organisms that can float considerable distances on air currents.
Airborne pathogens can travel through
heating and air conditioning systems to infect large numbers of people
Sweeping a floor or shaking out contaminated bed linens can stir up
airborne microorganisms and launch them on air currents. Agents of measles and tuberculosis, as well as many fungal infections, are commonly transmitted in this manner.
Vector
An organism that carries a pathogen to a susceptible host, typically by biting or stinging, creating another portal of entry into the body.
e.g. mosquitos, ticks, fleas, mites, and other insects
Portals of entry
normal body openings, such as the conjunctiva of the eye, the nares, mouth, urethra, vagina, and anus
Potential portals of entry
Abnormal openings, such as cuts, scrapes, and surgical incisions.
Common portals of entry include:
wounds, surgical sites, and insertion sites for tubes or needles
Susceptible (or compromised) host
A person who is at risk for infection because of inadequate defenses against the invading pathogen.
Factors that can increase susceptibility to infection:
Age (very young or very old), compromised immune system(cancer treatment or chronic illness), and immune deficiency condition (e.g., HIV, leukemia).
Infections are classified according to
their location in the body, whether it is the patient’s first infection, where it was acquired, and how long it lasts.
Local infections
Infections that cause harm in a limited region of the body, such as the upper respiratory tract, the urethra, or a single bone or joint
Systemic infections
occur when pathogens invade the blood or lymph and spread throughout the body
Bacteremia
the clinical presence of bacteria in the blood
Septicemia
is symptomatic systemic infection spread via the blood
Primary infection
the first infection that occurs in a pation.
Secondary infection
follow a primary infection, especially in immunocompromised patients
Exogenous healthcare-related infections
the pathogen is acquired from the healthcare environment
Endogenous healthcare-related infection
the pathogen arises from the patient’s normal flora, when some form of treatment (e.g chemotherapy or antibiotics) cause the normally harmless microbe to multiply and cause infection
Acute infection
Infections that have a rapid onset but last only a short time, such as the common cold
Chronic infections
Develop slowly and last for weeks, months, or even years
Latent infections
Cause no symptoms for long periods of time, even decades. e.g. Tuberculosis and HIV
Predictable stages of infection:
- Incubation
- Prodromal stage
- Illness
- Decline
- Convalescence
Incubation
The stage between successful invasion of the pathogen into the body and the first appearance of symptoms. The person does not suspect that he has been infected
Prodromal stage
Characterized by the first appearance of vague symptoms of infection. A person infected with a cold virus may experience a mild throat irritation. Not all infection have a prodromal stage.
Illness
The stage marked by the appearance of the signs and symptoms characteristic of the disease. If the patient’s treatments (if any) are ineffective, this stage can end in the death of a patient.
Decline
The stage during which the patient’s immune defenses, along with any medical therapies, successfully reduce the number of pathogenic microbes.
Convalescence
Characterized by tissue repair and a return to health as the remaining number of microorganisms approaches zero. May require only a day or two, for severe infections, as long as a year or more
Epidemic
An outbreak of a disease that suddenly affects a large group of people in a geographic region (e.g. a city or state) or in a defined population group (e.g. children, healthcare workers)
Pandemic
An exceptionally widespread epidemic–that is, one that affects a large number of people in an entire country or worldwide
e.g., H1N1 Influenza and malaria
Emerging infectious diseases
- Newly identified disease caused by an unrecognized microorganism
- Diseases occurring in a new geographic areas
- Microorganisms in animals that extend their host range to begin infecting humans
- Microbes that evolve to become more virulent
- Known diseases that dramatically increase incidence
- Organisms that are deliberately altered for bioterrorism
- Most emerging pathogens are viruses
Drug-resistant or multidrug-resistant
Microorganisms, mostly bacteria, that have mutated to develop resistance tone or more classes of antimicrobial drugs
The most significant challenge in treating patients with severe infectious disease is
antibiotic resistance
MDROs
multidrug-resistant organism
Risk factors associated with MDRO
- Severe illness
- Previous exposure to antimicrobial agents
- Underlying diseases or condition that make it difficult for the person to fight infection
- Invasive procedures and devices, such as dialysis
- Repeated contact with the healthcare system
- Advanced age
Examples of MDROs
MRSA, Clostridium difficile, vancomycin resistant enterococci (VRE), multidrug-resistant tuberculosis (MDR-TB), penicillin-resistant streptococcus pneumoniae
Staphylococcus aureas
lives on the skin and in the nose, usually without causing problems. If a person does have a “staph” infection it is normally treated with methicillin, but MRSA can’t be killed with this drug
Enterococcus faecium
Normal residents in the intestines and the femail genital tracts, and in the environment.
Strains have developed resistance to the antibiotics vancomycin and ampicillin and have become an important source of HRIs throughout the world
VRE (Vancomycin-resistant enterococci)
Leading cause of healthcare-acquired bacteremia (bacteria in the blood), surgical wound infection, and UTIs.
Clostridium difficile
Virulent strain of C. diff., a spore forming organism, has developed. 3% of healthy adults carry a harmless version, however it can become harmful when antibiotics destroy healthy bacteria that normally protect against the disease
Newer C. diff strain
is resistant to nearly all antibiotics and is virulent enough to cause sepsis, lasting intestinal damage, he need for colon removal, an even death.
It thrives in unsanitary hospital environments
Prevention of transmission in a healthcare facility (C. diff)
- Application of contact precautions for patients with diarrhea
- Accurate identification of patients
- Rigorous cleaning of patient rooms and equipment
- Consistent hand hygiene, using soap and water rather than alcohol-based handrubs
- Use a bleach-containing disinfectant for environmental disinfection
The human body has 3 “lines of defense” against infectious disease:
- Certain anatomical features limit the entry of pathogens
- Protective biochemical processes fight pathogens that do enter.
- The presence of pathogens activates immune responses against specific, recognized invaders
The first 2 lines of defense are
nonspecific; they have no means of adapting their response to each specific invader. They act in precisely the same way against any and all intruders from a simple cold virus to deadly fungal spores.
Primary defenses
the “soldiers.” Prevent organisms from entering the body.
e.g. the skin, respiratory tree, eyes, the mouth, the gastrointestinal tract, and the genitourinary tract
Superinfection
When broad-spectrum antibiotics used to treat infection eliminate normal flora in addition to those causing the infection. This allows other kinds of pathogens to multiply
Lysozyme
antimicrobial enzyme found in tears, saliva, and urine
Secondary Defenses
Pathogens that dodge the primary defenses and gain entry into the body and begin to release wastes and secretions and cause the breakdown of cells and tissues
Chemical activation of secondary defenses
- Phagocytosis
- The complement cascade
- Inflammation
- Fever
Phagocytosis
Process by which specialized white blood cells, called phagocytes, engulf and destroy pathogens directly
Phagocytic WBC include
Neutrophils, monocytes, and eosinophiles
Monocytes
Have the ability to differentiate into macrophages that specialize in cleaning up sites of injury or infection by phagocytizing pathogens, used WBCs, and cellular debris
Macrophages
specialize in cleaning up sites of injury or infection by phagocytizing pathogens, used WBCs, and cellular debris
Eosinophils
Occasionally phagocytic; are responsible mainly for binding to helminthes and releasing harmful toxins onto their surface
Basophils
Release histamine and heparin granules as part of the inflammatory response
Neutrophils
phagocytize pathogens
Lymphocytes
WBCs involved in specific immunity, produced from stem cells in the red bone marrow
- T cells: responsible for cell-mediated immunity; recognize, attack, and destroy antigens
- B cells: responsible for humoral immunity; produce immunoglobulin to attack and destroy antigens
The complement cascade
Process by which a set of blood proteins, called complement, trigger the release of chemicals that attack the cell membranes of pathogens, causing them to rupture. Complement also signals WBC called basophils, to release histamine which prompts inflammation
Inflammation
Process that begins when histamine and other chemicals are released either directly from damaged cells, or from basophils in response to activation of compliment
Monocytes
Able to phagocytize directly as well as to differentiate into macrophages, which help clean up damaged or inured tissue
Fever
Rise in core body temperature that increases metabolism, inhibits multiplication of pathogens, and triggers specific immune responses
Tertiary Defenses
People who recover from an infectious disease like measles and never get the disease again.
- Humoral immunity
- Cell-mediated immunity
Specific immunity
the process by which the body’s immune cells “learn” to recognize and destroy pathogens they have encountered before
Antigens
Molecules that trigger a specific immunity response
Humoral immunity
Response acts directly against antigens. In response to the presence of antigens, macrophages and a class of T cells stimulate B cells to produce antibodies
Antibodies
Also called immunoglobulin (Ig). Proteins with a base region and two arms that bind to target antigens and destroy them
Methods by which antibodies target and destroy antigens
- Phagocytosis
- Neutralization
- Agglutination
- Activation of complement and inflammation
Phagocytosis
Signal leukocytes (macrophages and neutrophils) to phagocytize the pathogens to which the antibodies are bound
Neutralization
Binding a pathogen’s attachment sites, antibodies disable the pathogens’ machinery for adhering to and invading body cells
Agglutination
Attaches two pathogenic cells so that by clumping them together, it reduced the cells’ activity and increasing the likelihood that the group will be detected
Activation of complement and inflammation
antibodies trigger the complement cascade and stimulate the release of inflammatory chemicals to destroy the antigen.
5 classes of immunoglobulins secreted by B lymphocytes
- IgM
- IgG
- IgE
- IgE
- IgA
- IgD
IgM
produced when an antigen is encountered for the first time
IgG
the most common immunoglobulin in the body
IgE
primarily responsible for the allergic response
IgA
Mucous membranes secrete IgA around body opening. Provide additional protection for vulnerable portals of entry
IgD
Antibodies form on the surface of B cells and trap potential pathogen to prevent it from replicating and causing disease
Cell-Mediated immunity
response acts directly against antigenic cells, acts to destroy body cells that have become infected
Cytotoxic (Killer) T cells
directly attack and kill body cells infected with pathogens
Helper T cells
Regulate the action of B cells in humoral immune response, and of cytotoxic T cells in cell-mediated responses.
Memory T cells
first time an antigen invades the body, T cells form that respond to that specific antigen
Suppressor T cells
Stop the immune response when the infection has been contained
Factors that increase host susceptibility
- Developmental stage
- Breaks in the 1st line of defense
- Illness or injury
- Tobacco Use
- Substance ABUSE
- Mult. Sexual Partners
- Environmental Factors
- Chronic Disease
- Medication
- Nursing and medical procedures
Active immunity
Natural process of being exposed to pathogens for the first time so that the body becomes exposed and creates antibodies for them.
Superinfections
opportunistic growth of harmful transient pathogens that are normally kept in check
Asepsis
Term that means absence of contamination by disease-causing microorganisms
Medical asepsis
Procedures that decrease the potential for the spread of infections
Contaminated
An object is considered contaminated if it becomes unclean–that is, if you suspect it may contain pathogens
Cleaning
the removal of visible soil from objects and surfaces
Disinfecting
Removes virtually all pathogens on inanimate objects by physical or chemical means, but it does not guarantee that all pathogens are eliminated.
High level disinfection
kills all organisms excepts high levels of bacterial sports
intermediate-level disinfection
kills mycobacteria, most viruses, and bacteria
low-level disinfection
kills some viruses and bacteria
Semicritical items
those that contact mucous membranes or nonintact skin
Noncritical items
supplies and equipment that come in contact with the kin but not mucous membranes
Sterilization
The elimination of all microorganisms (except prions)
Major sterilizing methods
- autoclaving with moist heat, 2. ethylene oxide gas, and 3. dry head
Critical items
Ones that pose a high risk for infection if they are contaminated with any microorganism
e.g. needles, urinary catheters, surgical instruments
Standard precautions
1st tier of protection, applies to all patients
Transmission-based precautions
2nd tier of protection
Prions
the protein particles that cause severe neurological degeneration in animals and humans such as in bovine spongiform encephalopathy “mad cow disease”
Surgical asepsis or sterile technique
requires creation of a sterile environment and use of sterile equipment
Surgical scrub
modification of the handwashing procedure. Involves an extended scrub of the hands using a sponge, nail cleaner, and bactericidal scrubbing agent.
Bioterrorism
Intentional release, or threatened release of disease-producing organisms or substances for the purpose of causing death, illness, harm, economic damage, or fear
