Infectious diseases Flashcards
What is the definition of disease?
Absence of health
What is disease caused by?
Microorganisms
Define infection
Growth of a microorganism on or in a host, resulting in injury to the host.
What infection caused by?
Pathogenic organisms
Define pathogens
A biological agent that causes disease in its host
What pathogens caused by?
Biological agents
What 3 things do pathogens do?
-Multiply
-Secrete organic exotoxins (primarily by bacteria) as part of their growth and metabolism
-Cause tissue damage
Define exotoxins:
Proteins that cause dysfunction, by damaging host cell membranes or by entering target cells and directly altering function.
What causes exotoxins?
Pathogens
What symptoms do exotoxins cause?
Fever, nausea, vomiting etc
Describe the pathway when exotoxins act as superantigens:
Resulting in a massive T-cell activation→cytokines→ macrophages→ overproduction of proinflammatory cytokines→ shock and organ failure
Define bacteria:
-Microscopic, single-celled organisms.
-Prokaryotes - lack nuclei and membrane-bound organelles
How are bacteria classified?
1.Morphology (size & shape)
-Cocci
-Bacilli
-Spirals
2. Biochemistry
3.genetic constitution.
What 4 infections associated with bacteria?
- Streptococcal pharyngitis (Strep throat)
- Klebsiella pneumonia (Bacterial pneumonia)
- Clostridium botulinum (Food poisoning)
- Salmonella typhimurium (Salmonellosis)
What are the resistant forms of bacteria known as ?
Endospores
When are endospores produced?
Most often produced due to nutritional deprivation.
What are endospores resistant to?
-The Environment
-Chemicals
When do endospores germinate?
Germinate in response to specific enviroment
Define viruses:
-Microscopic, single celled
-Carry their own DNA or RNA but never both. DNA and RNA are surrounded by protein coat known as capsid
How are viruses classified?
1.Chemical Nature of their nucleic acid
2.Size
3.Symmetry
What are the dormant Viruses in nervous system?
1.Herpes simplex virus 1(HSV1)
2.Herpes simplex virus 2 (HSV2)
What are other common viruses?
1.Rhinovirus (Common cold)
2.Human Papillomavirus (Warts; Genital Warts, Cervical & Anal Cancer)
3.Epstein-Barr virus
4.SARS-CoV-2
What is a virion?
-(viral particle) attaches to host cell, inserts its own genetic information, and then redirects host cell to produce new viruses
What are dormant viruses?
-Some viruses travel within nervous system
-They appear at nerve endings, causing symptoms and then leave sight and travel up nerve again
Define fungi:
-Macroscopic or microscopic
-They are eukaryotes
How do you classify fungi?
-Classified according to sexual repro.
-Medically important fungi are dimorphic
1. Candida: (yeast) single celled
2. Mold
What the classifications of fungi diseases?
1.Superficial: Discoloration-Tinea nigra
2.Cutaneuous: Involves keritenized tissues-Tinea pedia aka Athlete’s foot
3.Subcutaneous: Enter host through open skin
4.Systemic: Enters circulatory system and can be fatal-Candidemia
Define parasitic protozoa:
-Unicellular organisms -Neither plant nor animal.
-Larger than bacteria
How do classify parasitic protozoa:
Classified by their motility:
1.Ameboid: Slow cellular flowing locomotion
2.Flagellum: protein tail facilitates motility
3.Cilia: numerous short hair like projections/tails facilitate motility
4.Sporozoans: Non-motile, form spores
What are diseases associated with parasitic protozoa?
Can form cysts:
1. Trichomonas vaginalis (Trichomoniasis)
2. Plasmodium vivax (Malaria)
What are the 2 types of entry to the cell for diseases?
- Ingression: attachment of organism to cell surface and excretion of toxins. Ex: Pneumonia
- Penetration: Pathogens begin invading past the cell surface. Ex: Through cuts, vectors (fleas), flagella
What is Dissemination
The degree of spreading
What is the incubation period?
The time frame from when the host’s defenses are overcome until a substantial population has been achieved
What are the steps of infectious diseases?
- Encounter
- Entry
- Spread
- Multiplication
- Damage
What are the types of damage in a disease
- Direct: Cell death caused by the destruction of host cells or by release of toxins by the infectious agent
- Indirect: Caused by the alteration of the host’s metabolism
What are the factors involved in the degree of spreading of infection?
- Host
- Infectious organism
- Mode of transportation
- Reservoir
What are the 2 modes of transportation?
- Exogenous
- Endogenous
Define Exogenous:
-Transmitted from outside the body)
-Transfer of pathogens touching fomite (object that has been contaminated) by person or vector
Define Endogenous:
-Transmitted from inside the body
-Encounters with organisms already present in the body - normal flora.
What is endogenous entry a result of ?
-Result of being treated by broad-spectrum antimicrobial drugs that destroy normal flora.
-When normal flora belonging to a specific area is transported to a different area
What are the 3 classifications of Exogenous diseases?
- Droplet
- Airborne
- Contact
What are the types of droplet diseases?
Common cold, Influenza, Pneumonia, Meningitis,
Whooping cough
What are the types of airborne diseases?
TB, Measles, Varicella
What is a reservoir?
Site where an infectious organism can remain alive, multiply and from which transmission can occur.
What are health care associated infections?
-Infections that are acquired while receiving treatment in a health care setting for an unrelated condition.
-Compromised patients are more susceptible to HAI
What are the 2 classifications of HAI
- Nosocomial:
Hospital/health care facility acquired
Transmitted to infant from mother at birth - Iatrogenic:
Acquired due to an intervention performed by a practitioner
What are the sources of HAI?
- Medical personal
- Patients flora
- Contaminated Health care environments through fomites
- Invasive procedures
- Blood-Borne Pathogens
What are some examples of blood borne pathogens?
Hepatitis B Virus (HBV), Human Immunodeficiency Virus (HIV)
What are the impacts of Nosocomial infections
- Increases length of stay
- Increases antibiotic utilization
- Increases therapeutic intervention
- Increases monetary cost to the health care system and/or patient
What are the 3 types of Antibiotic Resistant Organisms?
- MRSA/HA-MRSA
- VRSA
- C. Diff.
When can you get MRSA and how is it transmitted?
-Likely to develop when antibiotics are used too often or incorrectly (prolonged hospital stay)
-Can occur in wounds, burns, IV sites.
-Transmitted by direct (hands) or indirect contact (fomite)
Where does MRSA colonize?
Colonizes on skin and in nose
Where does VRSA colonize?
Skin
When does VRSA occur and how is it transmitted?
-Transmitted by direct (hands) or indirect contact
-Likely to develop when antibiotics are used too often or incorrectly
What is C-diff caused by and what are the symptoms?
Effects those recently treated by antibiotics from touching contaiminated surface that disrupts normal bacteria of the GI tract.
Symptoms: Diarrhea to life threatening inflammation of the colon
What are the 4 different types of hand hygiene?
- Regular Hand washing
- Antiseptic hand washing
- Alcohol-based hand rub
- Surgical hand hygiene/antisepsis
How long should you do normal hand-washing?
40-60 seconds but health guide says 20
How long should you do Antiseptic hand washing?
15 sec
What are the 2 types of antiseptics?
Alcohol: antiseptic that is a disinfectant applied on skin
Betadine: iodine-based antiseptic that is used on skin
When should you use Standard Precautions (Tier 1)?
To be always used when any healthcare worker is caring for a patient.
When is Transmission Based Precautions (Tier 2) seen?
Designed to place a barrier to the spread of highly infectious diseases.
What are examples of contact diseases?
C-Diff, MRSA, VRSA, VRE,
What is the PPE for droplet precautions?
PPE: surgical mask, eye protection, gown & gloves
What is the PPE for patient and worker for airborne precautions?
-N95 “fit tested” respirator to be worn by healthcare workers.
-Patient should wear surgical mask which filters expired air.
-Negative pressure isolation room required
When is reverse isolation used and what is required to keep them safe?
-Patients at greater risk of acquiring infection
-Aseptic techniques and PPE required to prevent cross-infection
What is the Sequence to removing PPE?
Gloves
Face Shield/Goggles
Gown
Cap
Mask
What are the steps to removing a gown?
- Perform hand hygiene
- Unfasten ties
- Peel gown away from neck and shoulder
- Turn contaminated surface toward the inside
- Fold or roll into a bundle
- Discard
How should you remove a respirator?
- Perform hand hygiene
- Lift the bottom elastic over your head, first.
- Then lift off the top elastic
- Discard
What are the 5 times you should definitely preform hand hygiene?
- Before touching a patient
- Before a clean aseptic procedure
- After body fluid exposure risk
- After touching a patient
- After touching patient surroundings
