PBS Unit 3.1.1 -3.1.7 Study Guide
Unit 3.1.1 Outbreak
List the steps/measures recommended to minimize the spread of an infectious disease.
To minimize the spread of an infectious disease we should wash our hands, limit contact with other individuals, especially the infected, wear protective gear such as gloves and masks, take vaccines, and get tested regularly.
Describe the job of an epidemiologist.
An epidemiologist investigates the causes and patterns of disease and injury.
What are important skills for an epidemiologist to have?
An epidemiologist should be knowledgeable about pathology and clinical medicine to identify what is causing their patients pain and how to treat them. They should also be skilled in biostatistics to see which groups of people and how many people are affected. Lastly, they should be good communicators because they need to be able to communicate their findings with their peers, patients, and the world.
List the sequence of events that the CDC (Center for Disease Control and Prevention) would follow when investigating outbreaks in healthcare facilities. (HINT: See “DDT Protocol”)
During an outbreak, the DDT will head to the hospital to survey the magnitude of the disease by interviewing infected patients and gathering information. After analyzing the information, they will recommend new or revised measures or steps to prevent more patients from becoming infected. The CDC implements these suggestions and reviews what works and what doesn’t and creates a new plan based on the results.
Define the following terms:
sporadic disease: occurs infrequently and irregularly
epidemic: a sudden increase in the number of cases of a disease in a population
endemic disease: a disease perpetually present in a community or population within a specific geographical area.
outbreak: A sudden increase in the occurrence of a disease in a localized area
pandemic: an epidemic that has spread aross several countries or continents and affects a large number of people.
What is a nosocomial infection?
an infection acquired at the hospital
What are the most common nosocomial infections?
Pneumonia, gastrointestinal, UTI, bloodstream, skin, and soft tissue infections.
During an outbreak, what factors must epidemiologists consider when communicating information to the public?
who the information is reaching, when to release the information, the method of delivery, and what to include in the report.
Unit 3.1.2 Agents of Disease
Define “agents of disease”
the types of organisms that cause diseases
Describe infectious diseases.
disease that are contracted or caught. They can be transmitted to others.
What is a host?
the organism which another organism uses to its advantage.
What are pathogens?
a disease-causing organism
Complete the table below (use the table you created in Activity 3.1.2):
Type of Infectious Agent | Living or non-living | Description of the agent | How the agent can be contracted | The damage the agent can cause in a host | How an infection by the agent is diagnosed | How infection by the agent can be prevented and treated | One example of each agent |
Prions | non-living | Any type of various infectious proteins that are abnormal forms of normal cellular proteins. | The agent can be contracted through consuming meat containing prions, through contaminated medical equipment, or by receiving corneas or organs from infected individuals. | They cause normal proteins in the brain to fold abnormally. | The infection is diagnosed through an MRI, Cerebrospinal Fluid Analysis, electroencephalogram (EEG) which analyzes brain waves, and blood tests. | The infection can be prevented by properly cleaning and sterilizing equipment and educating prion-affected individuals not to donate their organs. There is no treatment for this infection but it can be slowed through medication. | Mad Cow disease |
Viruses | non-living | Infective agents that typically compromise an RNA or DNA core of genetic material surrounded by a protein coat. | Viruses can be contracted through touch, saliva, blood, sweat, or physical contact. | They infect cells and use them to reproduce into more virus cells destroying the original body cell and many tissues in the process. | Viral infections can be diagnosed through physical examination and physical testing. | This infection can be treated with over-the-counter medicine. It can be prevented by performing personal hygiene and taking vaccines. | The flu |
Bacteria | living | A single-celled, prokaryotic microorganism | They infect others by entering the body through the nose, eyes, and mouth, or a wound. They can be contracted by ingesting contaminated food or water, through inhalation, or sexual contact, or may result due to an imbalance in normal flora. | Bacteria can invade cells, cause tissue damage, and produce harmful toxins. | They are diagnosed through physical examination and clinical laboratory testing. | Bacterial infections can be treated using antibiotics. They can be prevented through the use of vaccines, maintaining sanitary conditions, and practicing personal hygiene. | Mycobacterium tuberculosis |
Protists | living | microscopic, single-celled. Eukaryotic, animal-like organisms. | They infect others through contaminated food or water. | Protists infect the digestive tract, blood, or organs of the body depriving a host of essential nutrients found in the food. They can also cause tissue and organ damage. | Infections caused by protists can be diagnosed through microscopic examination of fecal material. | Some types can be treated through antiprotozoal medication. They can be prevented by maintaining sanitary conditions and proper hygiene. | Giardia Iamblia |
Fungi | living | Saprophytic and parasitic spore-producing eukaryotic organisms that lack chlorophyll. | They infect others through spores, reproductive cells, and when they are inhaled or landed on a host. | Tissue damage | They are diagnosed using microscopic examination of the infected area, or blood taken from the host. | The treatment for this infection is antifungals. It can be prevented by avoiding contact with the infected host. | tapeworm |
Helminths | living | multicellular eukaryotic worms | They are contracted through the consumption of contaminated foods or water or by being bit by infected insects. | Helminths deprive their hosts of essential nutrients found in food and can cause tissue and organ damage. | The infection is diagnosed through microscopic examination of fecal material or blood. | Treatment for this type of infection is deworming medication. They can be prevented by avoiding exposure to food or water contaminated with feces, ingestion of meat from an animal infected with a form, and insect bites. | Taenia |
What are microbes?
microscopic agents
What is the normal flora (normal microbiota)?
bacteria that live inside our bodies
What is the role of the normal flora in our bodies?
help us digest food, protect from invading organisms, and provide us with vitamins.
Unit 3.1.3 Modes of Transmission
What is an infectious agent’s reservoir?
the place the agent used to live
What is a “susceptible” host?
anyone that is capable of contracting the disease
Given information on a specific pathogen, be able to describe the different components of the “chain of infection”.
Differentiate between direct and indirect contact.
Direct contact involves physical touch with an infected individual.
Indirect contact includes inhaling infected particles.
The number of organisms it takes to cause illness following exposure is known as infectious dose .
Which of these organisms is more dangerous based on their infectious dose? Influenza type A with >790 viruses of infectious dose or M.tuberculosis with >10 bacteria of infectious dose?
M. tuberculosis because it takes less than ten bacteria to infect someone.
What does the virus called SARS-CoV-2 cause?
Coronavirus disease
How can you contract COVID-19?
By being exposed to infectious fluids and being near someone who has the disease.
Describe the function of the immune system..
works to resist infection and destroy any pathogens that enter the body.
Define innate immunity.
immunity you are born with. The work to keep anything outside of your body from coming in.
Define acquired immunity:
specific immune defense systems, acquired over a lifetime and use antibodies to respond to specific antigens.
Describe the two forms of acquired immunity:
Acquired active immunity: acquired following infection and recovery. Your body makes antibodies
Acquired passive immunity: acquired from your mother
Explain why your immune system doesn’t usually attack your own body.
Sometimes, such as in the case of autoimmune diseases, your body doesn’t recognize cells that belong in the body and they start to attack it.
What are autoimmune diseases and what type of medications are used to treat them?
The immune system mistakes the cells in the body as invaders and attack them. Medications used to suppress the immune system are used.
Describe how each component of the innate immunity protects the body from infection by completing the table below:
Component | Mode of Protection | |
Tears | contain an enzyme that kills invading organisms and wash out invaders. | |
Nasal mucosa | traps any invaders. | |
Cilia | invaders are trapped in mucous and passed up and out | |
Stomach acid | has a pH of 2 and works to kill invaders | |
Secretions | urine, vaginal discharge, and defecation washes out organisms | |
Normal Flora | secretes chemicals to keep foreign invaders out and prevent them from attacking | |
Phagocytes | patrol the lungs and eat and digest invaders | |
Digestive enzymes | help kill invaders |
What is an antigen?
anything that stimulates an immune response
What is the function of T-cells?
A type of white blood cell produced by the thymus and involved in immune response
What is the function of B-cells?
a type of lymphocyte that matures in bone marrow and produces antibodies
What are antibodies? aka immunoglobulin
a protein produced by B cells that work to impair pathogens.
What are three functions of antibodies?
Antibodies function to block pathogens from entering cells, prevent bacteria from ingesting nutrients, and bind toxins released by pathogens to prevent them from causing harm.
What are memory cells?
T-cells
Distinguish between naturally acquired and artificially acquired immunity.
Naturally acquired immunity is when T-cells remember which pathogens to destroy, artificially acquired immunity works through injection of a vaccine.
Describe a vaccine and how it works.
A substance used to stimulate an immune response to create antibodies and provide immunity to a specific infection.
What is herd immunity?
a form of artificially acquired immunity that occurs when most of the population has gotten a vaccination.
Describe the following careers:
Computer scientist: uses computers and software to solve real world problems, creates simulations for the virologist to examine.
Virologist: studies viruses and how they affect us and our environment.
What is R0?
a variable used to measure how infectious an agent of disease is.
Why is it important to know how contagious an agent is?
knowing how infectious a disease is can help etiologists figure out a solution to how to treat the disease depending on the scale.
What is the meaning of the following R0 values?
R0<1: a sick individual will infect less than one other person.
R0 = 1: a sick individual will infect one other person
R0>1: a sick person will infect more than one person. Usually, 2-3 people will become infected.
How do you calculate R0?
number of new cases/number of existing cases
Unit 3.1.4 Evidence Evaluation
Define etiology.
the cause of a disease or condition and can include things like diet, lifestyle factors, genetics, or pathogens.
What is the etiology for
Flu: influenza virus
Athlete’s foot: caused by fungi that live on the skin hair, and nails
FH: a genetic condition that is caused by mutations in certain genes that affect how the body regulates an removes cholesterol from the blood.
For patients with respiratory tract infections, what sample would you collect?
mucous sample
For patients with skin infection, what sample would you collect?
skin culture
For patients with urinary tract infections, what sample would you collect?
urine sample
Why would it be helpful to use computers and artificial intelligence to analyze epidemiological data?
AI can process large amounts of data very quickly.
Unit 3.1.5 Isolation
What factors provide clues as to the identity of a bacterium?
We can look at the morphology, how organisms grow to identify bacterium.
What is the job description of a microbiologist?
A microbiologist studies the growth, structure, and development of microorganisms.
What is our normal flora?
Normal flora is the bacteria that lives in our bodies
Define “pure cultures”.
Pure cultures are generated from a single organism, they are essentially all clones of each other.
What does agar provide to bacteria?
Agar provides all the nutrients and water the bacteria needs to grow
What is a colony?
groups that bacteria grow in
Describe the purpose of an isolation streak.
to form bacteria colonies
Draw how you would make an isolation streak using 4 quadrants.
How do bacteria divide?
bacteria divide through binary fission, a process that creates clones of the same bacteria.
Describe the general rules for aseptic techniques.
aseptic techniques prevent contamination by separating the contaminants and taking precautions such as wearing safety gear and disinfecting surfaces.
Why is it important to follow aseptic techniques when working with microorganisms?
prevent contamination from occuring
If you are removing a bacterial sample from a test tube, when should you flame the mouth of the test tube?
you should flame the mouth of the test tube after you remove the bacterial sample.
When removing a bacterial sample from a plate, how long should you keep the plate open?
you should hold the cover above the plate like a clam to prevent as much bacteria from escaping.
Why must you let the loop cool after flaming before inserting it into broth or near a colony?
you don’t want to kill the bacteria
Why do you place inoculated petri plates upside down in an incubator?
when the petri plates are right side up the condensation drips down onto the bacteria. We put the plates upside down so the condensation from the bacteria drips onto the lid of the plate instead.
Colonies are considered large if they are > 1_ in diameter
Colonies are considered small if they are < 0.5_ in diameter
Write the name of the common form of bacterial colonies below:
_________Circular_____________ _________Irregular__________
Write the name of the common elevations of bacterial colonies below:
______Raised_____ ____Convex________ ______Flat_______
Write the name of the common margins of bacterial colonies below:
______Entire________ _______Undulate_________ _______Lobate_____
Unit 3.1.6 Gram Staining
Name the basic bacterial morphologies below:
Name the different bacterial arrangements below:
Bacilli: Individual Chain
Cocci: Individual Diplococci Chain Tetrad Staphylococci
Spirilla: Individual
What is the bacterial cell wall made of?
phospholipids
What is a Gram stain?
a differential staining technique named after Hans C J Gram
How does the peptidoglycan layer differ in Gram positive and Gram negative bacteria?
In gram positive bacteria the peptidoglycan is purple and thick, while the gram negative peptidoglycan is pink and thin.
Why are gram negative bacteria often more dangerous?
Gram negative bacteria are often more dangerous because they have an extra layer of lipopolysacharride outside of the membrane. This extra layer can have toxic effects on our bodies and can lead to a condition known as a septic shock.
What type of drugs would be effective against bacterial infections?
Antibiotics
Study the process of gram staining below and in the table describe the reaction and how long the treatment is applied for (where applicable).
Treatment | Describe the Reaction: | |
Fixation | Fixation is when the slide gets passed through a flame. This process allows the bacteria to stick to the slide so that we can stain them without having them wash off the slide. | |
Primary Stain | Our primary stain is crystal violet dye. It dyes the bacteria purple. How long is it applied for? It is applied for one minute | |
Iodine treatment | The iodine treatment binds with the crystal violet dye forming a large, water-insoluble complex How long is it applied for? It is applied for one minute | |
Decolorization | This process causes gram-negative bacteria to lose its color. Gram-positive bacteria stay the same. How long is it applied for? it is applied for 15-30 seconds | |
Counter Stain | The counter stain is the final stain used. Safranin is added and the gram-negative bacteria turns pink while the gram-positive remains purple. How long is it applied for? 1 minute |
After each reagent, the slide has to be rinsed with _________.
water
What is the most critical step of a Gram stain and why?
During the decolorization, if the slide is rinsed for too long, the bacteria will appear to be decolorized and false negatives may occur.
Why don’t Gram-positive cells appear red?
Gram-positive cells don’t appear red because they have a thick peptidoglycan layer that can absorb all the dye.
After the decolorization step, what color are Gram positive cells? Gram negative?
Gram-positive cells are purple while gram-negative cells are clear.
If you see different cell morphologies, arrangements, and/or both Gram positive and Gram negative organisms on a slide, what does this likely mean?
There is more than one type of bacteria on the slide.
Unit 3.1.7 Transmit the Tale
Explain the following ways medical information can be accessed and shared:
Journal articles: a collection of academic or technical articles written by experts on a particular topic. They can be printed, published online, or both.
Conferences: Events designed for professionals in a certain field to share information, and ideas, promote products and networking
Press releases and press conferences: Provide a quick delivery of news to public.
TV, radio, or print news: provides information about current events to the public.
Social media: information can be quickly accessed
Educational material: pamphlets and flyers found
What are peer-reviewed journal articles?
a vital avenue for medical profesionals and researchers to share interesting cases innovative research or challenges they are facing in their fields
What is an abstract?
targeted and succinct summary of the issue in the article
What is the MMWR and what is it used for?
It stands for the morbidity and mortality weekly report. It helps medical professionals stay updated on health news.
Define morbidity.
refers to having a disease or a symptom of disease or the rate of disease within a population.
Define mortality.
refers to the number of deaths in a certain group of people in a certain period of time.
What is a podcast?
an audio program that tells a story or relates to a particular theme.
PBS Unit 3.1.1 -3.1.7 Study Guide
Unit 3.1.1 Outbreak
List the steps/measures recommended to minimize the spread of an infectious disease.
To minimize the spread of an infectious disease we should wash our hands, limit contact with other individuals, especially the infected, wear protective gear such as gloves and masks, take vaccines, and get tested regularly.
Describe the job of an epidemiologist.
An epidemiologist investigates the causes and patterns of disease and injury.
What are important skills for an epidemiologist to have?
An epidemiologist should be knowledgeable about pathology and clinical medicine to identify what is causing their patients pain and how to treat them. They should also be skilled in biostatistics to see which groups of people and how many people are affected. Lastly, they should be good communicators because they need to be able to communicate their findings with their peers, patients, and the world.
List the sequence of events that the CDC (Center for Disease Control and Prevention) would follow when investigating outbreaks in healthcare facilities. (HINT: See “DDT Protocol”)
During an outbreak, the DDT will head to the hospital to survey the magnitude of the disease by interviewing infected patients and gathering information. After analyzing the information, they will recommend new or revised measures or steps to prevent more patients from becoming infected. The CDC implements these suggestions and reviews what works and what doesn’t and creates a new plan based on the results.
Define the following terms:
sporadic disease: occurs infrequently and irregularly
epidemic: a sudden increase in the number of cases of a disease in a population
endemic disease: a disease perpetually present in a community or population within a specific geographical area.
outbreak: A sudden increase in the occurrence of a disease in a localized area
pandemic: an epidemic that has spread aross several countries or continents and affects a large number of people.
What is a nosocomial infection?
an infection acquired at the hospital
What are the most common nosocomial infections?
Pneumonia, gastrointestinal, UTI, bloodstream, skin, and soft tissue infections.
During an outbreak, what factors must epidemiologists consider when communicating information to the public?
who the information is reaching, when to release the information, the method of delivery, and what to include in the report.
Unit 3.1.2 Agents of Disease
Define “agents of disease”
the types of organisms that cause diseases
Describe infectious diseases.
disease that are contracted or caught. They can be transmitted to others.
What is a host?
the organism which another organism uses to its advantage.
What are pathogens?
a disease-causing organism
Complete the table below (use the table you created in Activity 3.1.2):
Type of Infectious Agent | Living or non-living | Description of the agent | How the agent can be contracted | The damage the agent can cause in a host | How an infection by the agent is diagnosed | How infection by the agent can be prevented and treated | One example of each agent |
Prions | non-living | Any type of various infectious proteins that are abnormal forms of normal cellular proteins. | The agent can be contracted through consuming meat containing prions, through contaminated medical equipment, or by receiving corneas or organs from infected individuals. | They cause normal proteins in the brain to fold abnormally. | The infection is diagnosed through an MRI, Cerebrospinal Fluid Analysis, electroencephalogram (EEG) which analyzes brain waves, and blood tests. | The infection can be prevented by properly cleaning and sterilizing equipment and educating prion-affected individuals not to donate their organs. There is no treatment for this infection but it can be slowed through medication. | Mad Cow disease |
Viruses | non-living | Infective agents that typically compromise an RNA or DNA core of genetic material surrounded by a protein coat. | Viruses can be contracted through touch, saliva, blood, sweat, or physical contact. | They infect cells and use them to reproduce into more virus cells destroying the original body cell and many tissues in the process. | Viral infections can be diagnosed through physical examination and physical testing. | This infection can be treated with over-the-counter medicine. It can be prevented by performing personal hygiene and taking vaccines. | The flu |
Bacteria | living | A single-celled, prokaryotic microorganism | They infect others by entering the body through the nose, eyes, and mouth, or a wound. They can be contracted by ingesting contaminated food or water, through inhalation, or sexual contact, or may result due to an imbalance in normal flora. | Bacteria can invade cells, cause tissue damage, and produce harmful toxins. | They are diagnosed through physical examination and clinical laboratory testing. | Bacterial infections can be treated using antibiotics. They can be prevented through the use of vaccines, maintaining sanitary conditions, and practicing personal hygiene. | Mycobacterium tuberculosis |
Protists | living | microscopic, single-celled. Eukaryotic, animal-like organisms. | They infect others through contaminated food or water. | Protists infect the digestive tract, blood, or organs of the body depriving a host of essential nutrients found in the food. They can also cause tissue and organ damage. | Infections caused by protists can be diagnosed through microscopic examination of fecal material. | Some types can be treated through antiprotozoal medication. They can be prevented by maintaining sanitary conditions and proper hygiene. | Giardia Iamblia |
Fungi | living | Saprophytic and parasitic spore-producing eukaryotic organisms that lack chlorophyll. | They infect others through spores, reproductive cells, and when they are inhaled or landed on a host. | Tissue damage | They are diagnosed using microscopic examination of the infected area, or blood taken from the host. | The treatment for this infection is antifungals. It can be prevented by avoiding contact with the infected host. | tapeworm |
Helminths | living | multicellular eukaryotic worms | They are contracted through the consumption of contaminated foods or water or by being bit by infected insects. | Helminths deprive their hosts of essential nutrients found in food and can cause tissue and organ damage. | The infection is diagnosed through microscopic examination of fecal material or blood. | Treatment for this type of infection is deworming medication. They can be prevented by avoiding exposure to food or water contaminated with feces, ingestion of meat from an animal infected with a form, and insect bites. | Taenia |
What are microbes?
microscopic agents
What is the normal flora (normal microbiota)?
bacteria that live inside our bodies
What is the role of the normal flora in our bodies?
help us digest food, protect from invading organisms, and provide us with vitamins.
Unit 3.1.3 Modes of Transmission
What is an infectious agent’s reservoir?
the place the agent used to live
What is a “susceptible” host?
anyone that is capable of contracting the disease
Given information on a specific pathogen, be able to describe the different components of the “chain of infection”.
Differentiate between direct and indirect contact.
Direct contact involves physical touch with an infected individual.
Indirect contact includes inhaling infected particles.
The number of organisms it takes to cause illness following exposure is known as infectious dose .
Which of these organisms is more dangerous based on their infectious dose? Influenza type A with >790 viruses of infectious dose or M.tuberculosis with >10 bacteria of infectious dose?
M. tuberculosis because it takes less than ten bacteria to infect someone.
What does the virus called SARS-CoV-2 cause?
Coronavirus disease
How can you contract COVID-19?
By being exposed to infectious fluids and being near someone who has the disease.
Describe the function of the immune system..
works to resist infection and destroy any pathogens that enter the body.
Define innate immunity.
immunity you are born with. The work to keep anything outside of your body from coming in.
Define acquired immunity:
specific immune defense systems, acquired over a lifetime and use antibodies to respond to specific antigens.
Describe the two forms of acquired immunity:
Acquired active immunity: acquired following infection and recovery. Your body makes antibodies
Acquired passive immunity: acquired from your mother
Explain why your immune system doesn’t usually attack your own body.
Sometimes, such as in the case of autoimmune diseases, your body doesn’t recognize cells that belong in the body and they start to attack it.
What are autoimmune diseases and what type of medications are used to treat them?
The immune system mistakes the cells in the body as invaders and attack them. Medications used to suppress the immune system are used.
Describe how each component of the innate immunity protects the body from infection by completing the table below:
Component | Mode of Protection | |
Tears | contain an enzyme that kills invading organisms and wash out invaders. | |
Nasal mucosa | traps any invaders. | |
Cilia | invaders are trapped in mucous and passed up and out | |
Stomach acid | has a pH of 2 and works to kill invaders | |
Secretions | urine, vaginal discharge, and defecation washes out organisms | |
Normal Flora | secretes chemicals to keep foreign invaders out and prevent them from attacking | |
Phagocytes | patrol the lungs and eat and digest invaders | |
Digestive enzymes | help kill invaders |
What is an antigen?
anything that stimulates an immune response
What is the function of T-cells?
A type of white blood cell produced by the thymus and involved in immune response
What is the function of B-cells?
a type of lymphocyte that matures in bone marrow and produces antibodies
What are antibodies? aka immunoglobulin
a protein produced by B cells that work to impair pathogens.
What are three functions of antibodies?
Antibodies function to block pathogens from entering cells, prevent bacteria from ingesting nutrients, and bind toxins released by pathogens to prevent them from causing harm.
What are memory cells?
T-cells
Distinguish between naturally acquired and artificially acquired immunity.
Naturally acquired immunity is when T-cells remember which pathogens to destroy, artificially acquired immunity works through injection of a vaccine.
Describe a vaccine and how it works.
A substance used to stimulate an immune response to create antibodies and provide immunity to a specific infection.
What is herd immunity?
a form of artificially acquired immunity that occurs when most of the population has gotten a vaccination.
Describe the following careers:
Computer scientist: uses computers and software to solve real world problems, creates simulations for the virologist to examine.
Virologist: studies viruses and how they affect us and our environment.
What is R0?
a variable used to measure how infectious an agent of disease is.
Why is it important to know how contagious an agent is?
knowing how infectious a disease is can help etiologists figure out a solution to how to treat the disease depending on the scale.
What is the meaning of the following R0 values?
R0<1: a sick individual will infect less than one other person.
R0 = 1: a sick individual will infect one other person
R0>1: a sick person will infect more than one person. Usually, 2-3 people will become infected.
How do you calculate R0?
number of new cases/number of existing cases
Unit 3.1.4 Evidence Evaluation
Define etiology.
the cause of a disease or condition and can include things like diet, lifestyle factors, genetics, or pathogens.
What is the etiology for
Flu: influenza virus
Athlete’s foot: caused by fungi that live on the skin hair, and nails
FH: a genetic condition that is caused by mutations in certain genes that affect how the body regulates an removes cholesterol from the blood.
For patients with respiratory tract infections, what sample would you collect?
mucous sample
For patients with skin infection, what sample would you collect?
skin culture
For patients with urinary tract infections, what sample would you collect?
urine sample
Why would it be helpful to use computers and artificial intelligence to analyze epidemiological data?
AI can process large amounts of data very quickly.
Unit 3.1.5 Isolation
What factors provide clues as to the identity of a bacterium?
We can look at the morphology, how organisms grow to identify bacterium.
What is the job description of a microbiologist?
A microbiologist studies the growth, structure, and development of microorganisms.
What is our normal flora?
Normal flora is the bacteria that lives in our bodies
Define “pure cultures”.
Pure cultures are generated from a single organism, they are essentially all clones of each other.
What does agar provide to bacteria?
Agar provides all the nutrients and water the bacteria needs to grow
What is a colony?
groups that bacteria grow in
Describe the purpose of an isolation streak.
to form bacteria colonies
Draw how you would make an isolation streak using 4 quadrants.
How do bacteria divide?
bacteria divide through binary fission, a process that creates clones of the same bacteria.
Describe the general rules for aseptic techniques.
aseptic techniques prevent contamination by separating the contaminants and taking precautions such as wearing safety gear and disinfecting surfaces.
Why is it important to follow aseptic techniques when working with microorganisms?
prevent contamination from occuring
If you are removing a bacterial sample from a test tube, when should you flame the mouth of the test tube?
you should flame the mouth of the test tube after you remove the bacterial sample.
When removing a bacterial sample from a plate, how long should you keep the plate open?
you should hold the cover above the plate like a clam to prevent as much bacteria from escaping.
Why must you let the loop cool after flaming before inserting it into broth or near a colony?
you don’t want to kill the bacteria
Why do you place inoculated petri plates upside down in an incubator?
when the petri plates are right side up the condensation drips down onto the bacteria. We put the plates upside down so the condensation from the bacteria drips onto the lid of the plate instead.
Colonies are considered large if they are > 1_ in diameter
Colonies are considered small if they are < 0.5_ in diameter
Write the name of the common form of bacterial colonies below:
_________Circular_____________ _________Irregular__________
Write the name of the common elevations of bacterial colonies below:
______Raised_____ ____Convex________ ______Flat_______
Write the name of the common margins of bacterial colonies below:
______Entire________ _______Undulate_________ _______Lobate_____
Unit 3.1.6 Gram Staining
Name the basic bacterial morphologies below:
Name the different bacterial arrangements below:
Bacilli: Individual Chain
Cocci: Individual Diplococci Chain Tetrad Staphylococci
Spirilla: Individual
What is the bacterial cell wall made of?
phospholipids
What is a Gram stain?
a differential staining technique named after Hans C J Gram
How does the peptidoglycan layer differ in Gram positive and Gram negative bacteria?
In gram positive bacteria the peptidoglycan is purple and thick, while the gram negative peptidoglycan is pink and thin.
Why are gram negative bacteria often more dangerous?
Gram negative bacteria are often more dangerous because they have an extra layer of lipopolysacharride outside of the membrane. This extra layer can have toxic effects on our bodies and can lead to a condition known as a septic shock.
What type of drugs would be effective against bacterial infections?
Antibiotics
Study the process of gram staining below and in the table describe the reaction and how long the treatment is applied for (where applicable).
Treatment | Describe the Reaction: | |
Fixation | Fixation is when the slide gets passed through a flame. This process allows the bacteria to stick to the slide so that we can stain them without having them wash off the slide. | |
Primary Stain | Our primary stain is crystal violet dye. It dyes the bacteria purple. How long is it applied for? It is applied for one minute | |
Iodine treatment | The iodine treatment binds with the crystal violet dye forming a large, water-insoluble complex How long is it applied for? It is applied for one minute | |
Decolorization | This process causes gram-negative bacteria to lose its color. Gram-positive bacteria stay the same. How long is it applied for? it is applied for 15-30 seconds | |
Counter Stain | The counter stain is the final stain used. Safranin is added and the gram-negative bacteria turns pink while the gram-positive remains purple. How long is it applied for? 1 minute |
After each reagent, the slide has to be rinsed with _________.
water
What is the most critical step of a Gram stain and why?
During the decolorization, if the slide is rinsed for too long, the bacteria will appear to be decolorized and false negatives may occur.
Why don’t Gram-positive cells appear red?
Gram-positive cells don’t appear red because they have a thick peptidoglycan layer that can absorb all the dye.
After the decolorization step, what color are Gram positive cells? Gram negative?
Gram-positive cells are purple while gram-negative cells are clear.
If you see different cell morphologies, arrangements, and/or both Gram positive and Gram negative organisms on a slide, what does this likely mean?
There is more than one type of bacteria on the slide.
Unit 3.1.7 Transmit the Tale
Explain the following ways medical information can be accessed and shared:
Journal articles: a collection of academic or technical articles written by experts on a particular topic. They can be printed, published online, or both.
Conferences: Events designed for professionals in a certain field to share information, and ideas, promote products and networking
Press releases and press conferences: Provide a quick delivery of news to public.
TV, radio, or print news: provides information about current events to the public.
Social media: information can be quickly accessed
Educational material: pamphlets and flyers found
What are peer-reviewed journal articles?
a vital avenue for medical profesionals and researchers to share interesting cases innovative research or challenges they are facing in their fields
What is an abstract?
targeted and succinct summary of the issue in the article
What is the MMWR and what is it used for?
It stands for the morbidity and mortality weekly report. It helps medical professionals stay updated on health news.
Define morbidity.
refers to having a disease or a symptom of disease or the rate of disease within a population.
Define mortality.
refers to the number of deaths in a certain group of people in a certain period of time.
What is a podcast?
an audio program that tells a story or relates to a particular theme.
