3- Hospital Acquired Infection Flashcards
What is meant by a reservoir?
reservoir of an infectious agent = the habitat in which the agent normally grows and multiplies
Give some examples of diseases without intermediaries
STDs, measles, mumps, streptococcal infection
Why was smallpox eradicated after the last human case was identified and isolated?
humans were the only reservoir for the smallpox virus
What is the difference between a carrier and a vector?
a carrier is infected even if asymptomatic
a vector is not infected even if they have it on them
What are the three different types of Carriers?
incubatory: transmit during incubation period before illness begins
convalescent: recovered from illness but can still transmit
chronic: continue to harbour causative agent for weeks/months after initial infection
what is zoonosis?
infectious disease transmissible under natural conditions from vertebrae animals to humans
Give five ways in which a pathogen can leave a host
respiratory tract
urine
faeces
crossing placenta from mother to foetus
cuts or needles in skin
Describe and explain the two modes of Direct Transmission
direct contact: skin to skin, kissing, sex
droplet spread: sneezing, coughing, talking
Describe the three modes of Indirect Transmission
airborne: carried by dust/droplet nuclei in air
vehicles: food, water, blood, fomites (inanimate objects)
vectors: mosquitoes, fleas, ticks
Give 3 examples of non-specific factors that defend against infection
skin, mucous membrane, gastric acidity
How could Vehicleborne transmissions be reduced?
elimination/decontamination of vehicle
How could airborne transmissions be reduced?
modifying ventilation or air pressure
filtering/treating the air
How could vectorborne transmission be reduced?
controlling vector popn
Give 2 examples of interventions that aim to increase a host’s defence
vaccinations: promote development of specific antibodies
prophylactic use of antimalarial drugs: prevents infection from taking root
What kind of intervention might prevent a pathogen from encountering a susceptible host?
herd immunity: if high proportion of popn are resistant, those who aren’t will be protected since pathogen will be unlikely to find the few susceptible individuals
Where might HAIs become more of a problem in outpatient settings?
limited capacity for infection control compared to acute care setting
What are the 4 main risk factors of HAI?
POM B
Patient characteristics
Organisational factors
Medical procedures and antibiotic uses
Behaviour of healthcare staff
- List some ways in which HAIs can be prevented
Best practices: increase compliance amongst healthcare workers
Catheters: careful insertion, maintenance and prompt removal
Prevention: explore new approaches
What is a bacterial cell wall made of?
lipid bilayer membrane
peptidoglycan matrix
What are the differences in cell walls between gram negative and gram positive bacteria?
gram positive: thick peptidoglycan sheath around a single membrane
gram negative: thin layer of peptidoglycan between 2 lipopolysaccharide membranes