ch. 22 promoting asepsis & preventing infections Flashcards
Healthcare-Acquired Infections (HAI’s)
infections associated with healthcare giving setting
Nosocomial infections
these are more specific to hospital setting
Colonization
occurs when a microorganism invades the host but does not cause infection
Communicable disease
infectious process transmitted from one person to another
chain of infection
infectious agent reservoir portal of exit mode of transmission portal of entry susceptible host
normal flora
general term that is used for flora that is beneficial or even essential for human health and well-being.
Normal (resident) flora
microorganisms that are always present on or in a person and usually do not cause any disease.
Transient flora
episodic microorganisms found on or in a person. An example of this is the Norovirus, which can cause the stomach flu.
pathogens
causes disease
virulence
power of the organism
to cause disease
reservoir
living or nonliving material in or on which an infectious agent multiplies and/or develops and is dependent for its survival in nature.
reservoir for infections
People, animals, plants, water supplies
reservoir
Nutrients Moisture Temperature Oxygen pH & Electrolytes
portal of exit
site from where micro-organisms leave the host to enter another host and cause disease/infection.
modes of transmission
DIRECT CONTACT
Touch
Kiss
Sex
modes of transmission
INDIRECT CONTACT
Computer keyboard
pen
Stethoscope
portal of entry
site through which micro-organisms enter the susceptible host and cause disease/infection. Infectious agents enter the body through various portals, including the mucous membranes, the skin, the respiratory and the gastrointestinal tracts.
site through which micro-organisms enter the susceptible host and cause disease/infection. Infectious agents enter the body through various portals, including the mucous membranes, the skin, the respiratory and the gastrointestinal tracts.
pathogen
often enter the body of the host through the same route they exited the reservoir
Vector-borne diseases
human illnesses caused by parasites, viruses and bacteria that are transmitted by mosquitoes, sandflies, triatomine bugs, blackflies, ticks, tsetse flies, mites, snails and lice.
susceptible host
someone who is at the risk of infection
localized infection
infection stays local at the infected site
systemic infection
an infection that travels and spread through out the body. E.G. the blood stream
primary infection
the first time you are exposed to and infected by a pathogen.
primary infection
when does your body have no innate defenses against the organism, such as antibodies
secondary infection
infection that occurs during or after treatment for another infection
secondary infection
may be caused by the first treatment or by changes in the immune system.
secondary infection
A vaginal yeast infection after taking antibiotics to treat an infection caused by bacteria
pathogens
micro-organisms that are capable of causing diseases or infections.
endogenous infection
micro-organisms from a person’s own body cause an infection
exogenous infection
a micro-organism derived from sources outside a person’s own body causes an infection
acute viral infection
characterized by rapid onset of disease, a relatively brief period of symptoms, and resolution within days. It is usually accompanied by early production of infectious virions and elimination of infection by the host immune system
Chronic infections
most commonly caused by viruses – this is the case with diseases like hepatitis, herpes, and the Epstein-Barr virus, however, they can be caused by a range of different pathogens.
latent infection
infection that is hidden, inactive, or dormant. As opposed to active infections, where a virus or bacterium is actively replicating and potentially causing symptoms, are essentially static
incubation period
occurs in an acute disease after the initial entry of the pathogen into the host (patient).
incubation period
It is during this time the pathogen begins multiplying in the host. However, there are insufficient numbers of pathogen particles (cells or viruses) present to cause signs and symptoms of disease.
incubation period
During this period, the patient is unaware that a disease is beginning to develop.
prodromal period
occurs after the incubation period. During this phase, the pathogen continues to multiply and the host begins to experience general signs and symptoms of illness, which typically result from activation of the immune system, such as fever, pain, soreness, swelling, or inflammation.
period of illness
during which the signs and symptoms of disease are most obvious and severe.
Full blown s/s of disease are most obvious
period of decline
the number of pathogen particles begins to decrease, and the signs and symptoms of illness begin to decline. However,
patients may become susceptible to developing secondary infections because their immune systems have been weakened by the primary infection.
period of convalescence
patient generally returns to normal functions, although some diseases may inflict permanent damage that the body cannot fully repair.
epidemic
diseases are those that affect large number of people in one area simultaneously
pandemic
disease that has spread to more than one area
MRSA: Staphylococcus aureus
Lives on the skin and in the nose usually without causing any problems
“Staph” infections
usually treated with methicillin, but those infections that are resistant to the drug must be given something else to treat it.
“Staph” infections
The organism is spread by skin to skin contact and by living in crowded conditions.
“Staph” infections
It can survive on hands, clothing, environmental surfaces and equipment, it is easily spread to vulnerable patients
VRE: Enterococci
Normally resides in the intestine and the female genital tract, also occurs in the environment.
EColi
occur in the hospital and spread is attributed to the failure of infection control measures
EColi
leading cause of healthcare acquired bacteremia, surgical wound infections, and UTI’s.
EColi
Risk factors include previous long term use of abx therapy, a weakened immune system, surgical procedures, long term devices (catheters) or colonization
C-diff: Clostridium difficile
3% of healthy adults carry a harmless version of
C.diff
It can become harmful when abx destroy healthy bacteria that would normally protect against the disesase.
C. diff
A newer strain has emerged that is resistant to nearly all abcx and virulent enough to cause sepsis, lasting intestinal damage, the need for colon removal and even death.
C.diff
It thrives in hospital environments and the federal government is pressuring physicians and hospitals to better enforce sanitation standards and to prevent the overuse of prescription abx.
Preventing the spread:
Apply contact precautions for patients with diarrhea
Preventing the spread:
Accurately identify patients with GI issues or infection
Preventing the spread:
rigorous with cleaning patients rooms and equipment
Preventing the spread:
Consistent hand hygiene, using soap and water rather than alcohol-based hand rubs for mechanical removal of spores (spores can live on surfaces for days and alcohol based scrubs are not effective on C.diff. spores)
Preventing the spread:
Use a bleach-containing disinfectant for environmental disinfection
primary defenses: Respiratory Tree
Nares, trachea and bronchi are all covered with mucous membranes that trap pathogens, which are then expelled.
The nose hair filters the upper airway
The nasal passages, sinuses, trachea, and larger bronchi are lined with cilia that sweep microorganisms upward from the lower airways.
Coughing and sneezing forcefully expel organisms
Primary Defenses
skin mucous membranes urinary tract tears gastrointestinal tract
primary defenses: eyes
The lacrimal glands produce tears that contain lysozyme which is an antimicrobial enzyme.
Tears help the body wash infective organisms away
primary defenses: mouth
Saliva contains lysozyme and helps continually wash microbes from the teeth and gums
Normal flora in the mouth compete for nutrition with invading organisms, thereby limiting the number of pathogens
primary defenses: GI tract
Many organisms that reach the stomach are destroyed in its acidic environment. Those that successfully enter the small intestine face an antimicrobial action of the bile.
Normal flora in the intestine secrete antibacterial substances.
Diarrhea and vomiting are actually some of the first line defense mechanisms for pathogens that invade
Primary Defenses: G Urinary tract
is protected with mucous membranes.
The epitheisal cells lining the urethra and the anus secrete mucus, which adheres to pathogens to promote their excretion through urine and stool.
Urine is typically highly acidic and contains lysozymes as well.
Mucous membranes in the vagina also help keep pathogens from est. colonies there.
The vagina also has a high acidity environment and the normal flora keep pathogens in check.
SECONDARY DEFENSES: phagocytosis
special WBC that engulf and destroy pathogens directly.
SECONDARY DEFENSES: complement cascade
Proteins called complements, trigger the release of chemicals causing them to rupture.
Complements also signals basophils (another special WBC) to release histamine. Histamine prompts inflammation.
SECONDARY DEFENSES: inflammation
When histamine and other chemicals are released either from damaged cells, or from basophils being activated by the complement produces inflammation
Blood vessels dilate and become more permeable. This increases the flow of the phagocytes, antimicrobial chemicals, oxygen, and nutrients to the affected area.
SECONDARY DEFENSES: Fever
A rise in core body temp that increases metabolism, inhibits multiplication of pathogens, and triggers specific immune responses.
Believing that low grade fevers are a necessary natural defense mechanism, many clinicians do not treat a fever unless it is greater than 102F/38.9C
The classic s/s of inflammation
The classic s/s of inflammation is: localized warmth, and erythema because of increased blood flow. Also, fluid leaking from the more permeable blood vessels accumulates in the surrounding tissue, causing edema, pain and pressure on the nerves.
TERTIARY DEFENSES
active immunity passive immunity specific immunity lymphocytes B cells T cells
Active Immunity
Occurs when the body makes it’s own antibodies or T cells to protect the body against pathogens.
