Week 8 Flashcards
(13 cards)
What are the classes of infectious agents that most commonly cause systemic infections?
Bacteria
Viruses
Protozoa - vectors
Fungi - typically immunocompromised
Helminths
For the contact mode of transmission:
- list an example of an aetiological agent that causes systemic infections
- describe how the infectious agents gain access to the circulatory/nervous system (universal precautions)
Example infectious agents
- Staphylococcus aureus
- Streptococcus spp
- Neisseria meningitis
- HIV
Universal Precautions
- standard
+/- contact
+/- droplet
For the common vehicle mode of transmission:
- list an example of an aetiological agents that causes systemic infections
- describe how the infectious agents gain access to the circulatory/nervous system (universal precautions)
Example infectious agents
- Schistosoma
Universal precautions
- standard
* sanitation
For the vector mode of transmission:
- list an example of an aetiological agents that causes systemic infections
- describe how the infectious agents gain access to the circulatory/nervous system (universal precautions)
Example infectious agents
- Plasmodium falciparum
- Ross River virus
Universal precautions
- standard
* vector control
Why are the different populations across the lifespan more susceptible to systemic infections ?
- young babies/children cant be vaccinated
- older individuals don’t usually get boosters
- skin integrity decreases with age
- immunologically naive when young
- immunocompromised when old
- premature babies
- IV drug users
- HCW, plumbers etc higher exposure
Why are people with an impaired immune response more susceptible to systemic infections ?
- impaired pathogen recognition
- immune cross reaction
- neutropenic patient delayed response
Why are people with anatomical defects (heart valves, atherosclerosis) more susceptible to systemic infections ?
- regurgitation of blood (valve)
- decrease in shearing forces (atherosclerosis)
- overall increasing local colonization
Describe an example of how the closed systems and/or functions of each organ system facilitates transmission via endogenous reservoirs
Blood circulates around the body
- transportation of infectious agents
Mucous membranes
- contiguous/seeding upper respiratory tract infectious
Describe an example of how the closed systems and/or functions of each organ system facilitates transmission via exogenous reservoirs
Direct inoculation via wounding (gums, open fracture) -> circumvent natural defences
Iatrogenic
- indwelling devices/medical procedures
*new portals of entry
Describe 3 clinical signs associated with cardiovascular system infection and explain the role of timely diagnosis and empirical treatment
Clinical presentation
- fever (degree and duration)
- increased HR (decreased late sign)
- nausea
- loss of appetite (anorexia)
- decreased urine output
Diagnosis and empirical treatment
- broad-spectrum antimicrobials
- symptomatic treatment (antipyretic, anti-inflammatory, analgesia, fluids)
Describe 3 clinical signs associated with nervous system infection and explain the role of timely diagnosis and empirical treatment
Clinical presentation
- ALOC/confusion
- headache
- fever
- photosensitivity
- nuchal stiffness
Diagnosis and empirical treatment
- not all drugs cross blood-brain barrier
- antimicrobials
Describe each stage of biofilm development
Planktonic cells
Attachment
Monolayer - becomes irreversible
Microcolony
Biofilm
Dispersion - different breaking points
What are the evasion strategies ?
Escape from phagocytes
Concealment
Antigenic variation
Immunosuppression
No immune response
