Microbiology CH 11 - Host-Microbe Interactions Flashcards
Define Symbiosis
Sym- Together
-Biosis - Living
Does Symbiosis give the information about the nature of the relationship?
No
What is it called when both species benefit?
Mutualism
What is it called when one species benefits from an interaction and the other is not affected?
Commensalism
What is it called when one organism benefits and the other is harmed?
Parasitism
What is similar to Parasitism?
Predation
What is it called when one organism is harmed by the actions of another, but the other does not benefit from those actions?
Amensalism
What are Opportunistic Pathogens?
Organisms that are beneficial or harmless can become harmful
Can commensal gut bacteria become pathogenic if the opportunity arises?
Yes
Are Staphylococcus aureus and Clostridium difficile opportunistic pathogens?
Yes
Where does Staphylococcus aureus reside? What can it cause given the right conditions?
- Non-harmful member of skin microbiota
- Severe skin infections
Where does Clostridium difficile reside? What can it cause given the right conditions?
- Low levels of large intestine
- Normal gut flora is reduced, which leads to excessive growth and a chronic infection
Name 3 conditions that provide opportunities:
- Compromised immune system
- Malnutrition
- Excessive antibiotic treatment
What does it mean when it’s stated that the human body is mostly “non-human”?
TLDR; Viruses > Bacterial cells > Human cells
More viruses than bacterial cells; more bacterial cells than human cells
How many microbes are on our skin?
10^4 to 10^6 CFU/cm^2
More than anywhere else, microbes are in our ______________
digestive tract
How many microbes are in our mouth (saliva)?
10^8 to 10^9 CFU/ml
How many microbes are in our stomach?
10^2 to 10^3 CFU/ml
How many microbes are in our small intestine?
10^5 to 10^7 CFU/ml
How many microbes are in our large intestine?
10^9 to 10^12 CFU/ml
How many microbes are in our nose?
10^4 CFU/nasal swab
How many microbes are in our lungs?
10^4 CFU/ml
How many microbes are in our urogenital tract?
10^6 to 10^8 CFU/ml
What 7 factors differentiate microbes from one another?
- Location on the body
- Age
- Person to person
- Geography
- Dietary Lifestyle
- Antibiotic Use
- Health
What organism causes Toxic Shock Syndrome?
Staphylococcus aureus
Is Staphylococcus aureus an opportunistic pathogen?
Yes
What causes Toxic Shock Syndrome (mechanism)?
Set of toxins produced and enter bloodstream or wounds getting infected from the skin that cause massive immune reaction
Can Toxic Shock Syndrome be fatal? If so, what percentage of cases leads to a fatality?
Yes; 5%
What are the symptoms of Toxic Shock Syndrome?
Fever, vomiting, rash, rapid blood pressure loss, and loss of skin
Staphylococcus aureus causes what disease?
Toxic Shock Syndrome
What are the 2 main virulence factors of Staphylococcus aureus and what does each one result in?
- Beta-lactamase - makes it resistant to penicillin-type antibiotics
- Toxic Shock Syndrome Toxin - compound that causes immune reaction
What 2 factors are needed for treatment of Toxic Shock Syndrome?
- Treatment of symptoms to prevent organ failure
- Antibiotics
What kind of antibiotics do you want to AVOID when treating Toxic Shock Syndrome?
Antibiotics that aren’t Beta-lactams
Why is treatment of Toxic Shock Syndrome with antibiotics challenging?
Additional Abx resistance gene
What is MRSA and VRSA resistant to respectively? They are becoming more _______, especially in hospitals
- MRSA - Methicillin
- VRSA - Vancomycin
- common
Streptococcus pyogenes causes what disease?
Pharyngitis
What is another name for Pharyngitis?
Strep throat
What are the qualities of Streptococcus pyogenes as a bacterium?
Facultatively anaerobic, hemolytic, and gram-positive
Streptococcus pyogenes can lead to what diseases?
Scarlet Fever, Rheumatic Fever, Pharyngitis
What organism causes Pharyngitis?
Streptococcus pyogenes
What are the symptoms of strep throat?
Swollen lymph nodes, inflammation of back of pharynx, and pus-filled abscesses covering the tonsils
What are the 2 main important virulence factors for Streptococcus pyogenes?
- Capsules that contain Hyaluronic Acid
- M-Protein
Where is Hyaluronic Acid found? What is its function in Streptococcus pyogenes?
- Normal cells in the body
- Acts as camouflage against immune system
What is M-Protein?
Membrane protein that protects the bacterial cell from being targeted by immune cells (if recognized)
What is needed for treatment of Streptococcus pyogenes?
Long-term antibiotics
For other Streptococcus pyogenes diseases that are NOT pharyngitis, what other drugs may be used?
Anti-inflammatories
What are the qualities of Clostridium botulinum as a bacterium? Where is it found and in what form?
Rod-shaped, gram-positive, spore forming obligate anaerobe
Found in soil (usually spore form)
Clostridium botulinum causes what disease?
Botulism
What causes Botulism (mechanism)?
Toxin that acts as a muscle relaxant, leading to paralysis
What are the symptoms of Botulism?
Blurred vision, dizziness, dry mouth, progressive paralysis, and death
What is an alternative way Botulism can be contracted in adults? What about in infants?
HINT: This is why you don’t give babies honey
- Ingestion of toxin (rather than live cells)
- Ingestion of spores
What is Botulism’s virulence factor?
Botulinum toxin
Botulism is caused by what bacteria?
Clostridium botulinum
Describe Botulinum Toxin and how it functions
- World’s most toxic proteins
- Toxic protein binds to ends of muscle-controlling neurons
- Binding stops neuron from transmitting its message to muscle, leading to paralysis
Are small doses of Botulinum Toxin toxic or dangerous if directly injected into specific muscles?
No
What are the 2 ‘steps’ to treating Botulism? What is the alternative treatment for infants?
- Repeated washing of intestinal tract to remove Clostridium
- Antibodies to neutralize toxin
- Antibiotics in infant infections
How long do symptoms of Botulism last?
Years or are permanent
What are the qualities of Clostridium difficile as a bacterium?
Anaerobic gram-positive spore-forming rods
What disease does Clostridium difficile lead to (include alternative name)?
Pseudomembranous Colitis (C-Diff)
Where is Clostridium difficile found? When AND why does it become pathogenic?
- Common member of GI tract
- Becomes pathogen after broad-spectrum antibiotics treatment
- As normal gut microbiome dies off, C. difficile survive and reproduce rapidly
What are the symptoms of Colitis? The more lethal symptoms are found especially in __________ patients
Inflammation, possible necrosis (death) of colon walls, internal bleeding, and death
Elderly
What are the 2 main virulence factors of Clostridium difficile? What are these factors functions/result in?
- Production of toxins and enzymes, leading to hemorrhagic death of intestinal walls and actual symptoms
- Spores that are resistant to antibiotics (Cephalosporin and Penicillin), so it can survive while being hard to get rid of
What are the 2 treatment methods for Clostridium difficile? What does each one do?
- Stronger antibiotics such as vancomycin or metronidazole to kill vegetative cells
- Repopulation of GI tract with healthy community of microbes
___________ from healthy colons are incredibly effective against recurring infection
Fecal transplants
Pseudomembranous Colitis is caused by what organism?
Clostridium difficile
What are the qualities of Mycobacterium tuberculosis as a bacterium?
Gram-positive, acid-fast aerobic bacillus
Mycobacterium tuberculosis causes what disease?
Tuberculosis
Can people be carriers for Mycobacterium tuberculosis?
Yes
The rate of tuberculosis is relatively ________, due to its ______________
low; low virulence
What are the symptoms of Tuberculosis?
Persistent productive cough, frequently with blood in sputum, fever, and weakness (more symptoms can arise)
In Tuberculosis, what part(s) of the body are infected?
Lungs, BUT more organs can be infected
Tuberculosis is caused by what organism?
Mycobacterium tuberculosis
What is Mycobacterium tuberculosis’ virulence factor?
Mycolic Acid
What are the 2 functions of mycolic acid?
- Protects cell from immune system
- Protects cell from dehydration - allows survival outside the body for months
Can mycolic acid cell be swallowed by immune cells?
Yes
What happens when mycolic acid cell is swallowed by immune cells?
Won’t be digested in lysosome
What makes the cells of Mycobacterium tuberculosis acid-fast?
Mycolic Acid
What is the treatment for Tuberculosis?
Long-term antibiotic treatment