Clas #11 Flashcards
Define Virulence
The disease producing potential of a bacteria
Very virulent microorganisms are called…
pathogens
What is a saprophyte?
an environmental organism that feeds off of dead or decaying organic material, usually fungi.
*These are harmless to humans but can be opportunistic if host immune system is compromised
How do Prions affect their host organism?
They are abnormally shaped proteins that don’t actually replicate in a normal way–They attack other proteins, change their shape and make them into prions..Their propagation is unclear, so it is difficult to treat.
Prions can cause a neurodegenerative disease called…
Creutzfeldt-Jakob disease
How do viruses replicate?
Insert their genome (their own DNA) into the host cell DNA, then uses the cells energy to replicate.
*This is why viruses can’t replicate outside a living cell
Explain the physical structure of a virus
- small, no organized cellular structure
- protein coat surrounded by nucleic acid core
- some have lipoprotein envelope
How do latent viruses function?
Enter cell, insert genome, and remain dormant until stimulated
What is an example of a latent virus?
varicella-zoster, epstein-barr, herpes
What is an oncogenic virus?
a virus that can transform host cells to malignant cells during replication
- HPV
- Hep. B
- Epstein-barr
H1N1 and H3N2 are examples of what kind of virus?
influenza
What disease is caused by the retrovirus group?
HIV/AIDS
What kind of virus is caused by a single stranded RNA virus?
Enterovirus in mucus, saliva and stool, like poliomyelitis
What makes bacterial infections easier to treat than viral infections?
bacteria are a small, simple structure made up of a cytoplasm covered by a RIGID cell wall that is susceptible to anti-bacterial
Whats the difference between flagella and pilli on bacteria?
Flagella: arms that help propel the bacteria
Pilli: tiny microfilaments that help with adherence
How do these 3 different bacteria divide?
Streptococci..
Diplococci…
Staphylococci…
Strep: divide into chains
Dip: divide into pairs
Staph: divide into clusters
Define biofilm
structured community of bacteria
What are spores?
group of bacteria waiting for stimulation to replicate
What is the difference between aerobic bacteria and anaerobic bacteria?
aerobic require oxygen to replicate and anaerobic hate too much oxygen
What makes facultatively anaerobic bacteria more virulent than both aerobic and anaerobic?
these bacteria are more virulent because they have the ability to adapt and survive either with OR without oxygen
What colour are gram positive bacteria?
g+ are RED
What colour are gram negative bacteria?
g- are BLUE
What colour are acid-fast bacilli?
*TRICK! They don’t stain at all!
What are spirochets?
helical, long bacteria
These bacteria are smaller than normal bacteria that tend to be resistant to many antibiotics…
mycoplasms
Name two organisms that are known for having both viral and bacterial characteristics
- Rickettsiaceae
2. Chlamydiaceae
What is rickettsiaceae? How is it transmitted?
an organism with both viral and bacterial characteristics
-requires host nutrients AND cell ATP byproducts to replicate, carried by fleas, ticks and lice
What organism causes rocky mountain spotted fever and typhoid fever?
rickettsiaceae
What organism is known for causing ocular infections in newborns?
Chlamydiaceae
Why do fungal infections usually manifest ON the body surface rather than as internal infections?
they require a temperature less than normal body temperature
If your patient with a fungal infection was prescribed penicillin, would you as a nurse be concerned? Why or why not?
Yes, because fungal infections are often NOT susceptible to penicillin-like antibiotics d/t rigid cell wall
What is the difference between yeast infections and mold infections?
Yeast: waxy, creamy texture
Molds: cottony/powdery
Malaria and dysentery are examples of what kind of parasite?
Protozoa
How are protozoa parasites transmitted?
- host-host (sexual contact)
- Arthropod vector (lice, flea, ticks)
- contaminated food/water
Worm-like parasites are called….
helminths (roundworm, tapeworm, flukes)
How are helminths transmitted?
- ingestion of fertilized ova
- penetration through the skin by arthropod vector
What are arthropods? How are they transmitted?
live, disease carrying creatures
- Ticks, mosquitoes, flies, mites, scabies, lice, fleas
- clothing, bedding, combs/brushes
What is bubonic plague carried by?
Fleas and rats
If my child has lice, what disease might I be concerned about them acquiring?
epidemic typhus
What are 4 different portals of entry for infectious organisms?
- Penetration (primary, accidental, medical)
- Direct contact (secretions, mom-babe)
- Ingestion (must survive pH, enzymes, peristalsis and normal flora)
- Inhalation (must survive mucus, cilia, coughing, antibodies and phagocytes)
Why are ingested or inhaled infectious organisms considered “tough” when they cause illness?
Ingested organisms must survive the body’s pH, enzymes, peristalsis and normal flora before causing infection.
Inhaled organisms must survive mucus, cilia, coughing, antibodies and phagocytes before causing infection
What is the difference between endogenous and exogenous organisms?
ENDOGENOUS: are opportunistic normal flora already in the body that can cause infection when an individual is immunocompromised
EXOGENOUS: from an external source, like a fomite, animal, arthropod, inhalation
What is a nosocomial infection?
infection obtained in the hospital
Which are more potent, exotoxins or endotoxins?
Exotoxins
Define toxin
a substance that alters or destroys normal cells
What are exotoxins?
proteins released from bacteria during growth that inhibit cellular synthesis, and inhibit the function of the cell
What are endotoxins? How do they work?
lipopolysaccharides from cell wall of gram negative bacteria
-they induce cytokines, leukocytes, and T-lymphocytes, which results in increased capillary permeability
What 5 factors influence an organisms virulence?
- exotoxins
- endotoxins
- adhesion factors
- evasive factors
- invasive factors
What is the purpose of the adhesion factor of an organism?
refers to the ability of an infective organism to stick to the body
What does it mean if an organism is highly evasive? Give an example of an evasive organism
it is able to hide in the host immune system
-H. Pylori Bacteria
What does the invasive factor refer to?
refers to whether or not the infectious agent is able to produce products to help it move across barriers like cell walls
Describe the stages of the disease course
- Incubation, influenced by the portal of entry, the dose, and the health of the host
- Prodromal, where the initial symptoms manifest
- Acute, the maximum impact
- Convalescent, where the patient shows signs of improvement
What is a culture test?
propagation of microorganisms outside the body with artificial growth media
What is a serology test?
study of serum
What is an antibody titer?
The antibody titer is a test that detects the presence and measures the amount of antibodies within a person’s blood. The amount and diversity of antibodies correlates to the strength of the body’s immune response.
Which is more accurate: a culture test or a serology test?
CULTURE test
What is the advantage to DNA/RNA sequencing?
it can recognize specific things that both a culture and a serology study cant
When might a doctor prescribe a broad spectrum antibiotic for his patient?
When we don’t know what type of bacteria we are working with. These are effective for both gram negative and gram positive bacteria
Antibiotics that are lethal to bacteria are called…
bactericidal antibiotics
How do bacteriostatic antibiotics work?
the prevent bacteria from replicating, but as soon as we stop giving it, the bacteria can grow again. It does not kill the bacteria, it just stalls it long enough for the host’s immune system to jump in and kill the bacteria
Give two examples of bacteriostatic antibiotics
- Tetracycline
2. Sulpha
Antibiotics kill bacteria by disturbing what 4 things?
- Cell wall synthesis
- Protein synthesis
- Nucleic acid synthesis
- Bacterial metabolism
What are 4 ways that bacteria can fight back against antibiotics?
- create enzymes to inactivate antibiotics
- changing antibiotic binding site
- using different metabolic pathways
- changing their walls to keep the antibiotics out
How do antiviral agents work?
- block RNA and DNA synthesis and replication
- block virus’s ability to bind to cells
- block production of protein coat on viruses
How do anti fungal agents work?
they target cell wall substances are different than normal body cell wall
What are the 4 surgical options for viral/bacterial infection?
- drain
- debridement
- removal
- replacement (valve)
Is the “complement” system a part of innate immunity of adaptive immunity?
Innate
What type of immunity is activated by recognizing self/non-self?
Innate
What does the adaptive immune response respond to? Using what cells?
antigens from infection, tumor cells, and transplanted cells.
-B-cells that create antibodies
T-cells that direct B-cell activity
What are 2 key differences between innate immunity and adaptive immunity?
INNATE
-reacts to microbes
-uses leukocytes, macrophages and natural killer cells
ADAPTIVE
-reacts to antigens from infection, tumor, transplanted cells
-uses B-cells and T-cells
What does the complement system do?
assists antibodies and phagocytes to destroy pathogens
What is a hypersensitivity response?
an excessive or inappropriate activation of the immune response. This means that the body is damaged by the IMMUNE RESPONSE rather than by the antigen or allergen
Describe a Type 1 hypersensitivity response.
- allergic reaction, either systemic anaphylactic or local reactions
- rhinitis
- food allergies
- bronchial asthma
- hives
- atopic dermatitis
Explain the pathophysiology of anaphylaxis
a systemic response to the inflammatory mediators released in a type 1 hypersensitivity
- histamine, acetylcholine, kinins, leukotrienes and prostaglandins cause VASODILATION
- Acetylcholine, kinins, leukotrienes and prosaglandins all cause BRONCHOCONSTRICTION
Explain a type II hypersensitivity response
occurs when IgG or IgM attack antigens on the cell surface
- Cell Lysis (opsonization) as in a transfusion reaction, Rh disease or a drug reaction
- Inflammation as in glomerulonephritis or a transplant regection
- Cell dysfunction as in graves disease or myasthenia gravis
Explain the pathophysiology of a type III hypersensitivity response
blood vessels are damaged when antigen+antibody immune complexes deposit on the walls of blood vessels and activate the “complement” system,
What are some examples of a typer III hypersensitivity response?
- autoimmune vasculitis
- glomerulonephritis
- Systemic Lupus Erythemoatosus (SLE)
- Serum sickness
What is a type IV hypersensitivity response?
cell mediated response where T-helper cells attack antigens, even when the pathogen is not harming the cell, and host cells are damaged in the process.
What are the 2 types of type IV hypersensitivity response?
- Direct cell-mediated cytotoxicity with viral reactions
2. Delayed-type with TB skin test and allergic contact dermatitis
Define self-tolerance
ability to differentiate self from non-self
Explain the process of central tolerance and peripheral tolerance
LOOK UP
CENTRAL deletes T&B cells in the thymus and the bone marrow
PERIPHERAL deletes activated T&B cells
Explain the pathophysiology of AIDS
- caused by HIV attacking CD4 lymphocytes
- HIV attaches to CD4 T cell receptors and enters the cell
- Attaches own DNA to the DNA of the invaded cell
- uses the cell’s energy to reproduce more viruses
How would my patient with AIDS present?
- profound immunosuppression
- malignancies
- Opportunistic infections
- Wasting
- CNS degeneration
What is “wasting”?
cardinal sign of AIDS wherein the body is so exhausted that the individual is unable to hold on to body weight, and they lose at least 10% of body weight
How is HIV transmitted?
- pre-ejaculate, semen, vaginal fluid
- breast milk
- blood to blood contact by contaminated needles, transfusions, in-utero or during labor and delivery
- NOT IN SALIVA OR URINE
Explain stage 1 of HIV infection
*Primary infection phase
-signs of systemic infection 1-4 weeks post exposure.
*Rapid viral replication DECREASES CD$ T-cell count
fever, fatigue, myalgia, sore throat, night sweats, GI issues, lymphadenopathy, maculopapular rash, headache
When is HIV most contagious?
During the window period for 1-6 months prior to seroconversion
What is “seroconversion”
immune system response where antibodies against HIV appear
What occurs in the latent period of HIV?
- approx. 10 years
- no signs and symptoms
- Virus replicates
- CD4 T-cell count decreases
- possible lymphadenopathy
What can we expect if our patient has stage III AIDS?
- T-Cell count low
- death in 2-3 years without treatment
What is the leading cause of death with HIV? How does it manifest?
Tuberculosis infection with fever, night sweats, cough, and weight loss
What is pneumocystis jiroveci?
A respiratory infection common secondary to HIV.
How will my patient with jiroveci pneumonia present?
- foamy exudate that forms cysts in the alveoli
- mild cough
- fever
- SOB
- weight loss
Name some illnesses that occur secondarily to HIV
- J. pneumonia
- Esophagitis
- Aphthous ulcers (canker sores)
- gastroenteritis
What is HANDs?
-Syndrome of cognitive and motor dysfunction with behavioural and psychosocial symptoms
How might my patient with HANDs present to me?
- attention/concentration deficit
- mental/motor slowing
- apathy
What is Toxoplasmosis?
a parasitic infection caused by cat feces or raw meat
-fever, headache, confusion, lethargy, visual disturbances, seizures
What is progressive multifocal leukoenceophalopathy?
A virus that causes slow demyelination of white matter in the CNS
- progressive limb weakness, hemi-paresis, ataxia
- sensory loss, visual disturbances
- mental status changes
- seizures
What is Kaposi Sarcoma?
common malignancies on the endothelial lining of small blood vessels that cause violet lesions on the trunk, neck, head, and tip of nose
*These are painless at first but then they start to invade body tissues, pulmonary being the latest
What is the cardinal sign of Non-Hodgkin lymphoma?
WEIGHT LOSS
-fever, night sweats
What virus causes cervical carcinoma?
HPV
What is “wasting syndrome”?
involuntary weight loss > 10% in the absence of opportunistic infection or malignancy
What are the manifestations of “wasting syndrome”?
- diarrhea, multiple daily stool
- weight loss > 10% baseline
- chronic weakness
- fever
