UNIT V - 16 Flashcards
infection
An infection is the entry of an infectious agent, a microorganism (organism only visible with a microscope), into the body that multiplies and disrupts tissue integrity.
an infectious agent VS a microorganism
1 enter
2 multiply
3 disrupt tissue integrity
microorganism
organism only visible with a microscope
kən-ˌta-mə-ˈnā-shən
cross-contamination
Careful hand hygiene is essential to prevent cross-contamination.
pathogens
Microorganisms capable of causing disease are called pathogens.
ˈflȯr-ə
normal flora
Nonpathogenic/ˌnän-ˌpa-thə-ˈje-nik / organisms that are prevalent on and in the body are called normal flora.
mə-ˈnä-pə-ˌlīz
monopolize
Normal flora accomplishes this by occupying receptor sites on cells, monopolizing the nutrients, and secreting substances that are toxic to other microorganisms.
transitive verb
: to get a monopoly of : assume complete possession or control of
ˌen-dō-ˈtäk-sən
endotoxins
Some pathogenic microorganisms produce harmful toxins and others release endotoxins. Endotoxins are responsible for the symptoms seen in diseases such as botulism /ˈbä-chə-ˌli-zəm/, tetanus /ˈte-tə-nəs/, diphtheria /dif-ˈthir-ē-ə /, and Escherichia /ˌesh-ə-ˈrik-ē-ə/ coli infection.
ˈpre-və-lənt
prevalent
Nonpathogenic organisms that are prevalent on and in the body are called normal flora.
1: generally or widely accepted, practiced, or favored : WIDESPREAD
2: being in ascendancy : DOMINANT
3:archaic : POWERFUL
prevalent noun
prevalently adverb
bacteria
Infectious Agents –> bacteria
Bacteria are single-cell microorganisms lacking a nucleus that reproduce from every few minutes up to several weeks.
aerobic /ˌer-ˈō-bik/ vs anaerobic /ˌa-nə-ˈrō-bik ˌan-ˌer-ˈō- /
Infectious Agents –> bacteria –> aerobic vs anaerobic
Aerobic bacteria need oxygen to grow and thrive.
Anaerobic bacteria grow only when oxygen is not present.
Gram staining
stain a specimen –> treat the specimen with a contrasting dye –> gram-positive VS gram-negative: more dangerous –> produce an endotoxin
A laboratory technique called Gram staining is performed to help classify the bacteria’s outer cell surface.
a contrasting dye /ˈdī /
The specimen to be tested for bacteria is placed on a slide, stained, and then treated with a contrasting dye; those retaining the stain are gram-positive, and those losing the stain and taking up the counterstain are gram-negative.
retain
1a: to keep in possession or use
b: to keep in one’s pay or service
specifically : to employ by paying a retainer
c: to keep in mind or memory : REMEMBER
2: to hold secure or intact
ˌhe-mə-ˈra-jik
hemorrhagic shock
hem·or·rhage ˈhem-rij
Many gram-negative bacteria are more dangerous than gram-positive bacteria because they may produce an endotoxin that can cause hemorrhagic shock and severe diarrhea and can alter resistance to other bacterial infection.
morphology /mȯr-ˈfä-lə-jē /
cocci / ˈkäk-sē /
bacilli /bə-ˈsi-ˌlī /
spirochetes /ˈspī-rə-ˌkēt/
Classification of bacteria according to their morphology (shape) places them into one of three main groups: cocci (round), bacilli (rod shaped), and spirochetes (spiral). Some grow in chains (streptococci /ˌstrep-tə-ˈkä-ˌkī/), some in pairs (diplococci /ˌdip-lō-ˈkäk-ˌsī /), and some in clusters (staphylococci /ˌsta-f(ə-)lō-ˈkä-ˌkī /).
culture
specimen is transferred to a medium –>sensitivity tests–>antibiotic
Final identification involves chemical testing of the bacteria by performing a culture.
ˌen-dō-ˈtäk-sən
endotoxin
A heat-stable toxin associated with the outer membranes of certain gram-negative bacteria that is released when the cells are disrupted.
ˈfa-gə-ˌsīt
phagocyte
Cells (e.g., macrophages) capable of ingesting particulate matter.
in·gest in-ˈjest
ingested; ingesting; ingests
transitive verb
: to take in for or as if for digestion
ingestible in-ˈje-stə-bəl adjective
ingestive in-ˈje-stiv adjective
ˌfa-gə-sə-ˈtō-səs
phagocytosis
The engulfing of microorganisms and foreign particles by phagocytes.
en·gulf in-ˈgəlf en- engulfed; engulfing; engulfs transitive verb
1: to flow over and enclose : OVERWHELM
the mounting seas threatened to engulf the island
2: to take in (food) by or as if by flowing over and enclosing
engulfment in-ˈgəlf-mənt en- noun
/ˈek-s(y)ü-ˌdāt/
exudate
Fluid in or on tissue surfaces that has escaped from blood vessels in response to inflammation and that contains protein and cellular debris.
spores
/ˈspȯr/
Oval bodies formed within bacteria as a resting stage during the life cycle of the cell; characterized by resistance to environmental changes (heat, humidity, or cold).
vector
/ˈvek-tər/
Carrier that transports an infective agent from one host to another, such as animals, insects, and rodents.
virulence
/ˈvir-ə-lən(t)s ˈvir-yə-/
Degree to which a microorganism can cause infection in the host or invade the host.
Characteristics that affect virulence are the ability to
(1) adhere to mucosal surfaces or cell walls,
(2) penetrate mucous membranes,
(3) multiply in the body,
(4) secrete harmful enzymes or toxins,
(5) resist phagocytosis (destruction by white blood cells [WBCs]), and
(6) bind with iron (essential to bacterial growth).
Upper respiratory tract (nose, mouth, throat)
Normal Flora of the Body
Corynebacterium/ˌkȯr-ə-(ˌ)nē-bak-ˈtir-ē-əm / species
Enterobacter/ˈent-ə-rō-ˌbak-tər/ species
Haemophilus/hē-ˈmä-fə-ləs / species
Klebsiella/ˌkleb-zē-ˈe-lə / species
Lactobacillus/ˌlak-tō-bə-ˈsi-ləs/ species
Neisseria/nī-ˈsir-ē-ə/ species
Staphylococcus/ˌsta-f(ə-)lō-ˈkä-kəs/ species
Streptococcus/ˌstrep-tə-ˈkä-kəs/ (viridans/ˈvir-ə-ˌdanz / group)
Streptococcus pyogenes (group A)
Various types of anaerobes/ˈa-nə-ˌrōb /
ˌpī-ə-ˈje-nik
pyogenic
adjective
pyo·gen·ic ˌpī-ə-ˈje-nik
: producing pus
pyogenic bacteria
also : marked by pus production
pyogenic meningitis
Skin
Normal Flora of the Body
Acinetobacter/ˌa-sə-ˈnē-tō-ˌbak-tər / species
Corynebacterium/ˌkȯr-ə-(ˌ)nē-bak-ˈtir-ē-əm/ species
Staphylococcus aureus/ˈȯr-ē-əs/
Staphylococcus epidermidis
Yeasts
Small bowel and colon
Normal Flora of the Body
Anaerobes/ˈa-nə-ˌrōb /
Bacteroides/-ˈrȯid-(ˌ)ēz / species
Clostridium/ klä-ˈstri-dē-əm/ perfringens
Enterobacter/ ˈent-ə-rō-ˌbak-tər/ species (coliforms/ˈkō-lə-ˌfȯrm /)
Streptococcus/ˌstrep-tə-ˈkä-kəs/ faecalis (enterococci or group D)
Vagina
Normal Flora of the Body
Alpha-hemolytic streptococci
Enterobacteriaceae/ˌent-ə-rō-ˌbak-ˌtir-ē-ˈā-sē-ˌē/
Enterococci
Lactobacillus/ˌlak-tō-bə-ˈsi-ləs/ species
Many types of anaerobes
Staphylococcus epidermidis
MDROs
MRSA
VRE
ESBL
C. diff
The four most common multidrug-resistant organisms (MDROs) are
(1) methicillin/ˌme-thə-ˈsi-lən /-resistant Staphylococcus aureus (MRSA),
(2) vancomycin/ˌvaŋ-kə-ˈmī-sᵊn/-resistant Enterococcus (VRE),
(3) extended-spectrum beta-lactamase/ˈbā-tə-ˈlak-tə-ˌmās/ (ESBL)–producing pneumonia (Klebsiella/ˌkleb-zē-ˈe-lə / pneumoniae or E. coli/ˌē-ˈkō-ˌlī /), and
(4) Clostridium/klä-ˈstri-dē-əm/ difficile/ˌdē-fi-ˈsēl / (C. diff).
assay
/ˈa-ˌsā a-ˈsā /
Rapid MRSA assays can quickly identify MRSA bacterium in 1 to 5 hours by testing either a blood sample or nasal or groin swabs.
penicillin-resistant Streptococcus pneumoniae
carbapenem/ˌkär-bə-ˈpe-nəm/ -resistant Enterobacteriaceae/ˌent-ə-rō-ˌbak-ˌtir-ē-ˈā-sē-ˌē/
Another example of a drug-resistant organism is penicillin-resistant Streptococcus pneumoniae, which causes a form of pneumonia that can be difficult to treat. Another emerging threat to public health and safety is a group of resistant organisms called carbapenem-resistant Enterobacteriaceae, which are highly resistant organisms and can cause infections in the urinary tract, bloodstream, wounds, and lungs (Sheu etal., 2019).
antimicrobial
/ˌan-ti-mī-ˈkrō-bē-əl/
Patients must be educated about the correct use and possible misuse of antimicrobial (killing or suppressing growth of microorganisms) agents.
mutate
/ˈmyü-ˌtāt myü-ˈtāt /
Incomplete treatment allows some microorganisms to live, giving them a chance to mutate and develop drug resistance.
mutation noun
mu·ta·tion myü-ˈtā-shən
1: a significant and basic alteration : CHANGE
prions
/ˈprī-ˌän/
variant Creutzfeldt-Jakob/ˈkrȯits-ˌfelt-ˈyä-(ˌ)kōb- / disease
Prions are protein particles that lack nucleic acids and are not inactivated by usual methods for destroying bacteria or viruses. They do not trigger an immune response but cause degenerative neurologic disease such as variant Creutzfeldt-Jakob disease (a human version of mad cow disease).
protozoa /ˌprō-tə-ˈzō-ə/
pro·to·zo·on /ˌprō-tə-ˈzō-ˌän/
Protozoa are one-celled microscopic organisms belonging to the animal kingdom and can be parasitic in nature. Protozoa that are pathogenic to humans include the Plasmodium/plaz-ˈmō-dē-əm/ species that causes malaria/mə-ˈler-ē-ə /;
Entamoeba/ˌen-tə-ˈmē-bə / histolytica, which causes amebic dysentery/ˈdi-sᵊn-ˌter-ē /;
and other strains capable of causing diarrhea.
virus
Viruses are extremely small and can be seen only with an electron microscope (Fig. 16.2). They are composed of particles of nucleic acids, either DNA or RNA, with a protein coat and sometimes a membranous envelope.
rickettsia
/ri-ˈket-sē-ə/
Rickettsia are small round or rod-shaped microorganisms that are transmitted by the bites of lice, ticks, fleas, and mites that act as vectors. They multiply only in host cells. Examples of rickettsial infection include Rocky Mountain spotted fever and typhus/ˈtī-fəs /.
fungi /ˈfəŋ-ˌgī /
spore /ˈspȯr /
my·co·sis/ mī-ˈkō-səs / mycoses /mī-ˈkō-ˌsēz /
vaginal candidiasis /ˌkan-də-ˈdī-ə-səs/
Fungi are tiny, primitive organisms of the kingdom Fungi that contain no chlorophyll. Examples include yeasts and molds. Fungi feed on living plants, animals, and decaying organic material. They thrive in warm, moist environments. Fungi reproduce by means of spores. In humans, fungal infections are called mycoses. When the balance of normal flora is altered by antimicrobial therapy, fungal infections such as vaginal candidiasis may occur.
helminth/ˈhel-ˌmin(t)th/
parasitic/ˌper-ə-ˈsi-tik / worms
Helminths are parasitic/ˌper-ə-ˈsi-tik / worms or flukes/ˈflük / belonging to the animal kingdom. Pinworms, which mostly affect children, are the most common helminths worldwide. Roundworms and tapeworms are other helminths.
mycoplasmas
/ˌmī-kō-ˈplaz-mə /
Mycoplasmas are very small organisms without a cell wall. They cause infections of the respiratory or genital tract. Mycoplasma pneumoniae is an example.
chlamydia
/klə-ˈmi-dē-ə/
genitourinary/ˌje-nə-tō-ˈyu̇r-ə-ˌner-ē / and reproductive tracts
Chlamydia, another type of organism, affects the genitourinary/ˌje-nə-tō-ˈyu̇r-ə-ˌner-ē / and reproductive tracts and has become more common in the past 20 years.
/klə-ˈmi-dē-ə /
Chlamydia trachomatis
In countries where hygiene is poor, Chlamydia trachomatis is responsible for trachoma/trə-ˈkō-mə /, an eye disease that can cause blindness.
Causative Agent (Link One)
disinfection
VS
sterilization
Disinfection, which destroys or reduces infection-producing organisms, and sterilization, which removes all organisms, are methods used in the process of destroying microorganisms, pathogens, or toxins.
Causative Agent (Link One)
virulence / ˈvir-ə-lən(t)s /
Characteristics that affect virulence are the ability to
(1) adhere to mucosal surfaces or cell walls,
(2) penetrate mucous membranes,
(3) multiply in the body,
(4) secrete harmful enzymes or toxins,
(5) resist phagocytosis (destruction by white blood cells [WBCs]), and
(6) bind with iron (essential to bacterial growth).
Reservoir (Link Two)
Reservoirs are places where microorganisms are found.
Reservoirs can be infected wounds, human or animal waste, animals and insects, contaminated (made unclean) food and water, or a person with an infection.
Standard Precautions are used to prevent the spread of infection from the reservoir. Good hand hygiene is one of the most effective ways to prevent the spread of microorganisms. Using sterile (free from all microorganisms) technique, when appropriate, is another effective method; for example, it is used to insert an indwelling urinary catheter to help prevent the transfer of normal flora from the skin and mucous membranes into the sterile bladder, where it could cause an infection.
Portal of Exit (Link Three)
The portal of exit is the route by which a pathogen leaves the body of its host.
Portal-of-exit transmission can be interrupted by identifying and treating infected patients. Isolation techniques and barrier precautions that include the proper handling and disposal of secretions, urine, feces, and exudate can prevent pathogen transfer.
Mode of Transfer (Link Four)
body excretions or drainage
inanimate/(ˌ)i-ˈna-nə-mət / objects
fomites/ˈfō-ˌmīt /
aerosol/ˈer-ə-ˌsäl -ˌsȯl / route
Modes of transfer of pathogens include
(1) direct personal contact with body excretions or drainage such as from an infected wound;
(2) indirect contact with contaminated inanimate objects (called fomites), such as needles, drinking and eating utensils, dressings, clothing, and hospital equipment;
(3) vectors such as fleas, ticks, mosquitoes, and other insects that harbor infectious agents and transmit infection to humans through bites and stings;
(4) droplet infection, or contamination by the aerosol route through sneezing and coughing; and
(5) spread of infection from one part of the body to another.
1: not animate:
a: not endowed with life or spirit an inanimate object
aerosol/ˈer-ə-ˌsäl -ˌsȯl / route
aerosol
noun
aero·sol ˈer-ə-ˌsäl -ˌsȯl
1
: a suspension of fine solid or liquid particles in gas
Smoke, fog, and mist are aerosols.
airborne aerosol transmission of infective viral particles
also, aerosols plural : the fine particles of an aerosol
stratospheric aerosols
2
: a substance (such as an insecticide or medicine) dispensed from a pressurized container as an aerosol
also : the container for this
Mode of Transfer (Link Four)
How can the mode of transmission be interrupted?
What should we teach patients to interrupt the mode of transmission?
The mode of transmission can be interrupted by
effective hand hygiene,
proper disinfection and sterilization of medical equipment, use of both surgical (sterile) and medical aseptic (free of microorganisms) technique in performing procedures and diagnostic tests,
and use of Standard Precautions to prevent contamination.
Teach patients
to cover the mouth when sneezing or coughing,
to dispose of soiled tissues correctly,
to wash hands after contact with potentially contaminated items, and
to avoid people who have an infection to reduce transmission of
pathogens.
Current Centers for Disease Control and Prevention (CDC) recommendations are to sneeze or cough into the bended elbow rather than to cover the mouth with the hands. This way, the spread of the respiratory droplets is prevented, and hands are not contaminated.
Mode of Transfer (Link Four)
abatement programs
Controlling insects with abatement programs, such as mosquito control, and filtering air in health care facilities are other methods of reducing pathogen transmission.
Portal of Entry (Link Five)
Pathogens can enter the body through the mucous membranes of the eyes, nose, mouth, trachea, or skin.
Using only sterile and clean items when caring for patients reduces the entry of pathogens. Barrier precautions (gloves, masks, condoms), safe handling of food and water, good personal hygiene, avoidance of high-risk behaviors, and protection from insect bites and stings can prevent entry of microorganisms.
Susceptible/sə-ˈsep-tə-bəl / Host (Link Six)
virtue/ˈvər-(ˌ)chü / of age
A human host may be susceptible by virtue of age, state of health, or broken skin.
comorbidities/(ˌ)kō-ˌmȯr-ˈbi-də-tē /
They also tend to have comorbidities (more than one illness or disease at the same time).
mech·a·nism/ˈme-kə-ˌni-zəm/
These states seem to interfere with the body’s normal defense mechanisms.
lodge/ˈläj /
grooves
Do not wear jewelry when you are providing patient care because microorganisms become lodged in the settings of stones, in the grooves of rings, and on the skin beneath the jewelry.
