What are microbiology divided into?
- clinical microbiology
- applied microbiology (recombinant DNA technology)
- food microbiology (yeasts)
- environmental microbiology (microorganisms in the soil)
What is clinical microbiology? What does it relate to? What does causative agents include?
- the study of causative agents of human infectious diseases and their reactions
- related to pathogenesis, diagnosis, treatment and control of infection (+basic characteristics features)
- bacteria (bacteriology), virus (virology), fungi (mycology) and parasites (parasitology)
Why is it important to study clinical microbiology?
- to understand how microorganisms interact with individuals and population
- to understand how microorganisms cause diseases
- to understand how diseases can be prevented and controlled
- to understand the role of nurses in control and prevention of infection
What do nursing students need to know about microbiology?
- microbial diseases
- basic characteristics of microorganisms
- microbial pathogenesis
- diagnosis of infectious disease
- treatment of infection
- prevention of infection
What does the study of basic characteristics of microorganisms include?
- classification of microorganisms in the human body and the environment
- characteristics feature of microorganisms (bacteria, virus, protists and fungi)
- identification of normal microbiota and pathogens
What does the study of microbial pathogenesis and microbial diseases include?
- source of infections (how microorganisms enter a host and cause disease)
- route of transmission (how infection is transmitted in hospitals, communities and populations)
- etiology (cause), pathogenesis (development) and epidemiology (frequency and distribution) of infections of different body systems
What does the study of procedures and diagnosis of infectious diseases include?
- collection and transport of specimens
- identification of pathogens from collected specimens: bacterial culture and biochemical tests
What does the study of treatment and prevention of infections include?
- use of antimicrobial treatments: antibiotics and vaccines
- importance of aseptic techniques in patient management (sterilisation and disinfection)
- control the spread of infection in hospitals and communities: hand hygiene and personal protective equipments (PPE)
What are microorganisms? How are they named and should they be written? What can we do after the first use?
- organisms that can only be seen under microscope
- named by binomial nomenclature: genus name (starts with capital letters) and specific name (small letters)
- both names should be italicised or underlined
- scientific names can be abbreviated
How does a light microscope work? What is the total magnification and explain?
- use visible light to resolve objects –> visible light passes directly through the lenses and specimen
- total magnification = eyepiece magnification x objective magnification
- in a compound microscope, the image from the objective lens is magnified again by the eyepiece
What size range can be seen by the unaided eye, light, and electron microscope? What is the size range of fungi, protozoa, bacteria and viruses respectively?
- above 0.2mm (200um); above 200nm (0.2um); under 200nm (0.2um)
- fungi (above 200um)
- protozoa (between 20um and 200um)
- bacteria (between 0.2um and 20um)
- viruses (between 2nm and 0.2um=200nm)
What are the types of microscopes? Give their characteristics and resolving power respectively.
- light microscope
=> observe the morphology of microorganisms such as bacteria, fungi, protozoa and algae under living (unstained) or non-living (stained) state
=> cannot observe microbes less than 0.2um (200nm)
=> resolving power: 0.2um - TEM (transmission electron microscope)
=> examine cellular and viral internal structures
=> gives 2D images only
=> specimen is non-living
=> resolving power: 0.2nm - SEM (scanning electron microscope)
=> examine surface features of cells and viruses
=> gives 3D images
=> specimen is non-living
=> resolving power: 20nm
What are the major types of microorganisms? Give a mind-map.
- microbes –> cellular microbes; acellular microbes
- cellular microbes –> prokaryotes; eukaryotes
- acellular microbes –> viruses
- prokaryotes –> bacteria
- eukaryotes –> fungi and protist (protozoa and algae)
Give four comparisons of prokaryotes and eukaryotes in terms of their characteristics.
- prokaryotes vs eukaryotes
=> no true nucleus; have true nucleus
=> no membrane-bound organelles (eg. mitochondria and chloroplast; have membrane-bound organelles
=> simpler and smaller; more complex
=> reproduced by binary fission; reproduced by mitosis and meiosis
What is the classification of microorganisms? And what are their cell type and form?
- bacteria (prokaryotes, unicellular)
- virus (acellular)
- fungi (eukaryotes, unicellular or multi-cellular)
- protists (eukaryotes, unicellular or multi-cellular)
Where can microorganisms be found?
- in the environment and human body
What are sterile sites and where are they? What are their respective systems?
- sites where no microorganisms should be found in the human body
- brain and spinal cord (CNS)
- blood (circulatory system)
- kidneys (urinary system)
- lungs (respiratory system)
- ovaries and testes (reproductive system)
Which microbes are beneficial and which are harmful?
- normal microbiota (normal flora)
=> non-pathogenic that live symbiotically in the human body
=> does not cause disease
=> usually beneficial to humans
=> very abundant as there are 10^13 body cells which there are 10^14 normal flora
=> eg. lactobacilli - pathogens
=> have the ability to cause disease in health individuals - opportunistic pathogens
=> do not cause disease under normal conditions, they wait for opportunities to cause disease (only cause disease in people with immunodeficiency)
=> eg. e coli, staphylococcus
What are the types of microbe-host relationships? Give one example for each type.
- mutualism (both benefit) (eg. E. coli)
- commensalism (one benefit one unaffected) (eg. Staphylococcus)
- parasitism (one benefit and one harmed) (eg. H1N1)
What benefits will be brought to humans and bacteria in mutualism?
- human
=> bacteria synthesise vitamins (vitamin B and K)
=> bacteria produce digestive enzymes to break down food (eg. polysaccharides in plant cell wall )
=> protect host by preventing pathogenic organisms from growing - bacteria
=> provide place for them to survive and multiply
=> obtain food source
How do pathogens cause infectious diseases and microbial intoxication?
- infect and colonise internal or external body surface –> inflammation and tissue damage
- produce toxin –> ingestion of toxin –> disease (food poisoning)
