Test 3 Flashcards
**Concept of antibiotics:
- Treat bacterial infections by either killing bacteria or preventing them reproducing.
**Antiseptic methods
- To control bacterial balance, especially to prevent infections in contaminated wounds
- Alcohols, chlorhexidine and peroxide
**Helminths, parasites and protozoa
Helminths:
- Worms
- Multicellular
- Tropical climates
- Type of parasite
Parasites:
- Live on or inside other organisms (hosts)
Protozoa:
- One-celled animals
- Type of parasite
**Concept of vaccination
- To stimulate the body’s immune system to produce antibiotics that fight disease without causing the disease itself.
**Bacteria Characteristics
- Prokaryotic
- Unicellular
- Have DNA and ribosomes
- Exist almost everywhere on earth
- No nucleus
- Rigid cell wall, cytoplasm and ribosomes
- Like a warm, dark and moist environment
**Microorganisms around us
- Found in air, water, soil and inside our bodies.
**R0 value
Refers to the contagiousness and transmissibility of infectious pathogens
**Viruses versus bacteria
Cell structure:
Bacteria are single-celled organisms, while viruses are not cells. Viruses are made up of genetic material (DNA or RNA) surrounded by a protein coating.
Survival:
Bacteria can survive on their own, inside or outside the body, while viruses need a host, such as a human or animal, to multiply.
Antibiotics:
Antibiotics are effective against bacterial infections, but not viral infections. Antiviral drugs are effective against a few viral diseases, such as HIV, hepatitis B and C, influenza, and herpes.
Symptoms:
Bacterial and viral infections can cause similar symptoms, such as fever, coughing, sneezing, vomiting, diarrhea, fatigue, and inflammation.
**How does bacteria cause disease?
Bacteria produce disease in one of two ways:
- Using cells for food: The bacteria break down healthy cells for food, destroying tissues
- Releasing toxins: The bacteria produce a toxin (poisonous protein) that is released into the bloodstream where it can travel throughout the body, disrupting normal activity and damaging tissue
**Sporulation
Sporulation is a process where bacteria form a tough, protective spore to survive harsh conditions until they can become active again.
Start: The bacterial cell divides unevenly, forming a mother cell and a forespore (a small cell inside the mother cell).
Engulfment: The mother cell surrounds the forespore, creating a double-layered membrane around it.
Coat Formation: A protective coat forms around the forespore.
Cortex Formation: A thick peptidoglycan layer (cortex) develops between the forespore’s inner and outer membranes.
Release: The mother cell breaks apart, releasing the mature spore.
The mature spore is now highly resistant and can survive extreme conditions.
**Antibiotics
▪Bactericidal
➢Kills bacteria, reduces bacterial load
Bactericidal agents inhibit synthesis of bacterial cell walls by affecting peptidoglycans Penicillins & cephalosporins Amoxicillin
▪Bacteriostatic
✓Inhibit growth and reproduction of bacteria
Bacteriostatic agents affect Protein production, DNA synthesis, Bacterial metabolic activities, Bacteriostatic drugs: Tetracyclines & Erythromycin,
**Microbiology terminology
Epidemic/Outbbreak:
- Disease occurance among a population that is in excess of what is expected in a given time and place.
Cluster:
- Group of cases in a specific time and place that might be more then expected.
Endemic:
- Disease or condition present among a population at all times.
Pandemic:
- A disease or condition that spreads across regions.
**Vaccines
How do they work:
- The body is exposed to a weakened or dead pathogen
- The body’s immune cells make antibodies to attack the pathogen
- If the body is exposed to the pathogen again, the body will be prepared with antibodies
Types:
Live attenuated: contain weakened pathogen; require 1-2 doses. Examples: rotavirus, varicella
Subunit: contain killed, antigenic component of pathogen; require several doses (booster shots). Examples: pneumococcal
Inactivated: contain killed pathogen; require several doses (booster shots). Examples: Hepatitis A, rabies, inactivated poliovirus vaccine
Toxoid: contain toxin made by pathogen; may require booster shots. Examples: Diphtheria, pertussis
mRNA vaccines:
mRNA vaccines carry genetic material that teaches our cells how to make a harmless piece of “spike protein,” which is found on the surface of a virus.
Cells display this piece of spike protein on their surface, and an immune response is triggered inside our bodies. This produces antibodies to protect us from getting infected if the virus enters our bodies.
**AIDS
- Caused by HIV virus, a retrovirus that infects T cells thus weakening immune system.
More then 39 million people have died from HIV since recognised in 1981. - Transmitted through unprotected sex, needle sharing, blood products.
- If untreated it will usually lead to death from infection.
- Other symptoms include: weight loss, fever, night sweats, tiredness, diarrhea and sores of the mouth, anus or gentials.
What are pathogens?
Microorganisms that cause disease, representing about 3% of all known microbes.
What is microbiology?
Microbiology is the study of very small living organisms, called microorganisms or microbes, including bacteria, algae, protozoa, fungi, viruses, and helminths.
What is spontaneous generation?
The outdated theory that living organisms could arise from non-living matter.
**What are Koch’s Postulates?
A set of criteria used to establish a microorganism as the cause of a disease:
The microorganism must be found in every case of the disease.
It must be isolated and grown in pure culture.
The pure culture must cause the disease in a healthy host.
The microorganism must be re-isolated from the newly infected host.
What are opportunistic pathogens?
Microorganisms that normally do not cause disease but can become pathogenic in certain conditions, such as a weakened immune system.
What was Louis Pasteur’s contribution to microbiology?
Pasteur disproved spontaneous generation and developed the germ theory of disease. He also developed vaccines for diseases like rabies and anthrax.
What are the main branches of microbiology?
Basic Microbiology
Industrial Microbiology
Pharmaceutical Microbiology
Agricultural Microbiology
Sanitary Microbiology
Environmental Microbiology
What are some major historical infectious diseases?
Bubonic plague
Smallpox
Tuberculosis
Syphilis
Influenza
What role do microbes play in fermentation?
Microbes, such as yeast and bacteria, are responsible for the fermentation process, used in food preservation and alcohol production.
