Microbiology (U3) Flashcards
Microbiology definition?
Study of MOs
- Too small for naked eye
- Effects of large numbers often visible
Five MO categories?
Bacteria, fungi, protozoa, parasite, virus
Two MO categories?
Normal flora (resident), pathogenic (disease causing)
What are the three ways MOs cause disease?
- Use nutrients needed by cells and tissues
- Damage cells directly (destroying/reproducing inside cells)
- Produce toxins
- Diseases are localized/become systemic
- Direct/indirect contact (transmission)
How MOs cause problems
When pathogenic in nature/displaced from natural environment, can cause inflection/disease
Disease defintion?
Any deviation from health disruption of tissues/organs
Infection definition?
Condition where pathogenic microbes penetrate host’s defense enter tissues and multiplies
What are infection and disease caused by?
Caused by microbes/their products (infectious disease)
Two factors in development of an infection?
True pathogen and opportunistic pathogen
True pathogen definition?
Capable of causing disease in a healthy person with normal immune defenses
Opportunitistc pathogen definition?
Causes disease when the host’s defenses are compromised/when they grow in part of the body that is not normal to them
What are patterns of infection?
Localized, systemic, focal and mixed, primary, secondary, and acute and chronic
What is a localized infection?
Microbes enter the body, remain confined to specific tissue
What is a systemic infection?
Infection spreads to several sites within a system
What is a focal infection?
Infectious agent breaks loose from local infection then carried to other tissue
What is a mixed infection?
Several microbes grow simultaneously at infection site (polymicrobial)
What is a primary infection?
Initial infection
What is a secondary infection?
Another infection by a different microbe
What is an acute infection?
Rapid with severe but short lived effects
What is a chronic infection?
Progresses and persist over a long period of time
Signs definition?
Objective evidence (quantitative, visual)
Symptoms definition?
Subjective evidence (felt)
What are the signs of infection in the blood?
Changes in the number of WBCs circling the blood
Leukocytosis definition?
Increase in WBCs
Septicemia definition?
MOs are multiplying in the blood and present in large numbers
Two types of septicemia?
Bacteremia and viremia
What is bacteremia?
Small numbers of bacteria present in the blood, not necessarily multiplying
What is viremia?
Small numbers of viruses present in the blood, not necessarily multiplying
What is the persistence of mircrobes?
Apparent host recovery does not mean microbes are removed (latency, chronic carrier, sequalae)
Latency definition?
After initial symptoms in certain chronic conditions, microbes can become periodically active and produce recurrent disease
- Person may or may not shed it during latent stage
Chronic carrier definition?
Person with latent infection who sheds infectious agent
Sequalae definition?
Long term/permanent damage to tissue/organs
What are the three types of living reservoirs?
Carrier, asymptomatic, passive
Carrier definition?
Person who harbours pathogens and spreads it to others, may or may not have had the disease
Three types of asymptomatic carriers?
Incubation, covalescent and chronic
What is incubation asymptomatic?
Spreads the infectious agent during incubation period
What is convalescent asymptomatic?
Recuperating without symptoms
What is chronic asymptomatic?
Individual who shelters infectious agent for a long time
Passive carrier definition?
Contaminated HCP picks up pathogens and transfers them to other patients
What measures frequency of cases?
Prevalence, incidence, mortality rate, morbidity rate
Prevalence definition?
Total number of existing cases with respect to the entire population (usually a percentage of a population)
Incidence definition?
Measures the number of new cases over a certain time period (compared with general healthy population)
Mortality rate definition?
Total number of deaths in a population due to a certain disease
Morbidity rate definition?
Number of people afflicted with a certain disease
What are the patterns of disease?
Endemic, sporadic, epidemic, pandemic
Endemic definition?
Disease that exhibits a relatively steady frequency over a long period of time in a specific geographic locale
Sporadic definition?
When occasional cases are reported at irregular intervals
Epidemic definition?
When prevalence of a disease is increasing beyond expected
Pandemic definition?
Epidemic across countries, declared by WHO
