Medical Microbiology Flashcards
What is epidemiology?
The study of how often different disease occur within or between populations, an integral part of a basic description
Why is epidemiology used?
To identify diseases
To identify outbreaks
To find the sources of illnesses
To identify risk factors for diseases
To identify interventions that change the risk or course of a disease
What are the first steps of epidemiology?
Who gets ill? - Age, ethnicity, gender
Do they have a common occupation or pastime?
Do they have an “event” in common?
Do they live/work/study in proximity to eachother?
How is data collected?
Abstracting from already available sources
Surveys
Physical examination
Clinical studies
Screening programmes
Disease surveillance programmes
How can an epidemiological population be defined?
Geographically
Occupation
Age
Gender
Race
What are the key measure in a population?
Incidence and prevalence
What is the key measure of the risk of disease?
Relative risk
What are opportunistic pathogens?
Pathogens that exploit us when we have something else wrong
What is the reservoir?
Where we find the microbes
What is a vector?
Something that transmits the microbe from the reservoir to us
Where do we get infections from?
Environmental sources - Food, water, air
Other animals - Directly, indirectly, as food
Other humans
Our own normal flora
What are some key interventions that can be used?
Vaccinations
Antibiotic therapy
Isolation and quarantine
What is the aim of antimicrobial therapy?
To kill or inhibit the microbe without harming the patient
What is intrinsic resistnace?
Resistance which is always present and doesn’t present a major concern - “pre exposure resistance”
What is acquired resistance?
A species that was once sensitive to an antibiotic becomes resistant
What are the four major mechanistic groups?
The antimicrobial is destroyed or inactivated
The target site in/on the microbe is altered
There is a reduction in the permeability of the microbial cell wall
The step where the antimicrobial acts is completely circumvented
What are some examples of environmental interventions?
Control of reservoirs
Control of vectors
Provision of clean water
Food industry intervention
Incineration of infectious waste
Quarantine
Large scale disinfection
What are the four sub-disciplines of microbiology?
Bacteriology
Virology
Parasitology
Mycology
How are bacteria and fungi usually researched?
By culture, and sometimes molecular
How are viruses researched?
Electron microscopy and tissue culture
How are parasites researched?
Microscopy, molecular being introduced
What are bacteria and fungi cultured in?
Non-selective agar - A medium that hasn’t had anything added
Selective agar - A medium that has had agents added to it
Enrichment medium - Highly nutritional medium
Discriminatory/differential agar - Enable the differentiation between different organisms
What other factors can be modified in medias?
Temperature
Atmosphere
Selection pressures
What are some simple tests that can be conducted on a culture?
Oxidase
Catalase
Coagulase
