Chapter 23: Asepsis & Infection Control Flashcards
(38 cards)
Infection
Is a disease state that results from the presence of pathogens in or on the body
Pathogens
Disease-producing microorganisms
Infection cycle
Infectious agent Reservoir Portal of exit Means of transmission Portals of entry Susceptible host
Bacteria
Most significant & most commonly observed infection-causing agents in health care institutions
Categories: shape, gram stain, need for oxygen
Bacteria categorization- Shape
Spherical- cocci
Rod- bacilli
Corkscrew- spirochetes
Bacteria categorization- Oxygen
Aerobic- need O2
Anarobic- don’t need O2
Bacteria Categorization- Gram Stain
Gram +: thick cell wall that resists decolorization (loss of color) & are stained violet. STAIN
Gram -: chemically more complex cell walls & can be decolorized by alcohol. DO NOT STAIN
Virus
Smallest of all microorganisms, visible only with an electron microscope
Cause infections:
Cold, hepatitis, AIDS,
Anti-virals: given in prodromal stage? Shorten full stage of the illness
Fungi
Plant-like organisms (mold & yeasts) that also can cause infection, are present in the air, soil, & water.
Examples infections:
Athlete’s foot(tinea pedis), ringworm (dermatomycosis), yeast infections (candidiasis).
Antifungals
There is some resistance
Parasites
Organisms that live on or in a host & reply on it for nourishment.
Example: malaria (serious dx that occurs when a parasite infects a certain type of mosquito that then feeds on peeps).
Not all organisms to which a perp is exposed to cause dx.
Organism’s potential to produce a disease: # of organisms, virulence of organism, competence of peep’s immune system, length & intimacy of the contact between the peep & organism
Virulence
Ability to cause disease
(Factor affecting organism-parasite to produce dx in a peep).
QSEN
Quality & Safety Education for Nurses
ID safety as one of leading issues in health care
Endemic
Occurs w predictability is one specific region or population can appear in a different geographic location
Example:
Dengue fever that is an endemic in southeast Asia has the potential to emerge in the US & pose a major public health problem.
In these cases, countries draw information from one another to learn about tmt options
Normal Flora
Microorganisms that commonly inhabit various body sites & are a part of the body’s natural defense.
Other factors intervene? A usually harmless organism may generate an infection.
Opportunist
Bacteria that don’t normally cause a problem but with certain factors, may potentially be harmful in susceptible people.
Examples: Escherichia coli (E. Coli)- normally resides in intestinal tract & causes no harm. Migrates to urinary tract? UTI
Clostridium difficile (C. Difficile)- resides in person’s body but shows no s/s infection (colonization). Infection is present once s/s show of the disease.
Need microscopic visualization to reveal presence of bacteria.
Person’s defense system are either effective or ineffective. Ineffective? Infection will occur.
Reservoir
For growth & multiplication is the natural habitat of the organism.
Reservoirs that support organisms pathogenic to human:
Other people, animals, soil, food, water, milk & inanimate objects
Reservoir- People
Show s/s of the dx & others don’t (carriers).
Carriers- transmit the dx.
Example:
HIV antibody? Probably infected. S/s AIDS may not show for years (10).
Can still transmit dx by sex, shared needles & syringe, infected preg woman to baby during pregnancy, birth, or breastfeeding.
Kids in daycare can spread E.coli from kid to kid.
Nurses can inadvertently transfer pathogenic organisms to pts through artificial nails, ineffective handwashing, improper glove use to IMMUNOCOMPROMISED pts.
Reservoir- Other
Rabies virus- animals like dogs, squirrels, bats, raccoons. Person contracts it by being bitten.
West Nile virus- animals like birds. Mosquitoes feed on infected birds, become infected & pass infection to people when feeding on their blood. Unusual weather conditions have led to a significantly larger crop of mosquitoes, which has resulted in more cases than usual
Soil- organisms that cause gas gangrene & tetanus.
Water- harbor Giardia, E.coli 0157-H7 & Shigella. Drinking or swimming in contaminated H2O can begin infectious cycle.
Food- undercooked ground beef & fresh leafy veggies have been ID as responsible for recent E.coli outbreaks. CDC recommends beef be cooked until well done & new laws keep Fruits & veggies safer when they are grown, picked & washed.
Milk- can contain Listeria unless it’s pasteurized. Recent outbreak traced to contaminated cantaloupe.
Inanimate objects- influenza virus. Spread if a perp touches a contaminated article & then touches one’s eyes/nose.
Portal of Exit- Humans
Respiratory, GI, GU, breaks in skin, blood & tissue.
Means of Transmission
Some transmitted by >1 route.
Enter the body by way of the contact route, directly or indirectly.
Direct- involves proximity between susceptible host & infected person/carrier such as touching, kissing, sex. Health care workers can transmit organisms to susceptible people through touching.
Indirect- personal contact w an inanimate object, such as touching a contaminated instrument.
>60% of nurses’ scrubs = pathogenic bacteria.
Proper hand hygiene & glove use can interrupt the transmission of dangerous bacteria from nurses to patients.
Paper has also been ID as a place bacteria can survive, from paper health care worker’s hands to pt.
Contaminated blood, food, H2O, or inanimate objects (fomites) are vehicles of transmission.
Vectors can transmit organisms from one host to another by injecting salivary fluid when a human bite occurs.
Microorganisms can also be spread through airborne route when infected host coughs, sneezes, talks, or when organism becomes attached to dust particles. Particles < 5mcm.
Another means of transmission is through droplets. Similar to airborne. Particles > 5mcm.
Vector
Mosquitoes, ticks, lice.
Are nonhuman carriers that transmit organisms from one host to another by injecting salivary fluid when a human bite occurs.
Portal of Entry
Point at which organisms enter new host. Organism must find a portal of entry to a host or it may die.
Entry route to new host often is the same as exit route from prior reservoir.
Resp, GU, GI, skin.
Stages of Infection
Incubation Period: interval between the pathogen’s invasion of the body & the appearance of s/s of infection. Organisms are growing & multiplying. Length varies. Cold- 1-2 days. Tetanus 2-21 days.
Prodromal Stage: pt. Is most infectious. Early /s present but are often vague & nonspecific, ranging from fatigue & malaise to a low-grade fever. Period lasts several hours-several days. Pt often unaware of being contagious. Result? Infection spreads.
Full Stage of Illness: specific s/s. Type infection determines length of illness & severity of manifestations. S/s limited or occur in only one body area are referred to as localized symptoms. Manifested throughout body? Systemic symptoms.
Convalescent Period: recovery period from infection. Varies according to severity of infection & the pt’s general condition. S/s disappear & person returns to healthy state. Depending on type of infection, may be temporary/permanent change in pt’s precious health state even after convalescent period.
Pt may continually pass through 4 phases w same infection, herpes.
Body’s Defense vs. infection
ITIS: protective mechanism that eliminates the invading pathogen & allows for tissue repair to occur. Helps the body neutralize, control or eliminate offending agent & prepare site for repair. Also occurs in response to injury. Acute or chronic process.
S/s acute inf. redness, heat, swell, pain, loss of fx, usually appear at site if injury/itis.
Vascular/cellular stages main components: responsible for appearance of s/s.
Vascular stage: small blood vessels constrict in area followed by vasodilation of arterioles & venules that supply area. Increase in blood flow= redness & heat. Histamine is also released, leading to increased permeability of vessels, = allows protein-rich fluid to pour into area. At this point, swell pain loss of fx can occur.
Cellular stage: WBC (leukocytes) move wuickly to area. Neutrophils (primary phagocytes) engulf organism & consume cell debris & foreign material. Exudate composed of fluid, cells, & itis products released from wound. Exudate may be serous, sanguinous, purulent. Amount exudate depends on size/location wound. Damaged cells repaired by regeneration (replaced w identical cells) or formation scar tissue.
IMMUNE RESPONSE: involves specific body responses to an invading foreign protein, bacteria or in some cases body’s own proteins. Complex mechanisms that constitute the immune response occur as the body attempts to protect/defend itself.
Foreign material is antigen, body reacts by making antibodies.
Antigen-antibody rx (humoral immunity), one component overall response.
Cell-mediated defense (cellular immunity) other component. Increase lymphocytes (WBC) that destroy or react w cells the body recognizes as harmful.
Help to defend the body specifically vs. bacterial, viral, & fungal infections, malignant cells.
