Micro Exam 4

Mycobacteria are slow growing _____________.

Bacilli

Mycobacteria is (aerobic/anaerobic)

aerobic (even microaerophilic)

What is the key virulence factor for mycobacteria and why is it effective?

Virulence factor= Mycolic acid rich cell wall

• Resists chemicals, acids, detergents, antibiotics, and immune defenses

• Prevents characterization via Gram-staining

How is mycobacteria characterized (stained)?

Using acid-fast or fluorescent stains (mycolic acid resists gram stains)

What organism is termed “Acid Fast Bacilli”?

Mycobacteria

How is Mycobacteria tuberculosis (Mtb) transmitted?

Inhalation of contaminated air droplets

True or False: Mtb can be transmitted via shaking hands, contact, and sharing food/drinks

False (Respiritory only)

(Pulmonary TB/Extrapulmonary TB) is the most common manifestation of the disease.

Pulmonary TB

True or False: Mtb can disseminate and infect other body systems

True (Extrapulmonary TB)

________ are the only known resevoir of Mtb.

Humans

________ is also known as the white plague or consumption.

Mtb

True or False: Mtb is an obligate human parasite

True

Describe the three possible outcomes after inhaling Mtb infectious droplets:

• Infection eliminated- Bacteria can not establish infection

• Latent infection- Not fully elimated, but controlled in dormant state (asymptomatic)

• Infection- Can be subclinical or active, severity determined by host response

How is TB “walled-off” to cause a latent infection?

Granullomas

What are the symptoms of active TB?

• Chronic, productive coughing

• Fever, night sweats, fatigue, shortness of breath etc.

What symptom of TB is indicative of lung damage and invasive disease?

Bloody sputum

What are considered risk factors for contracting TB?

• People who work/reside with people who have or are at high risk for Mtb infection (Homeless, IVD users, people with HIV, correctional facilities, nursing homes)

• People with weakened immune systems (HIV, chronic disease, chemo, poverty, malnutrition)

How is Mtb detected and diagnosed?

TST- Tuberculin skin test (2 step PPD)

Can Mtb be a part of the healthy human micorbiota?

No

How are both active and latent TB treated?

Both are curable with multi-drug antimicrobial therapy

How can Mtb infection be prevented?

• BCG vaccination (used under select circumstances like countries with a high prevalence of childhood TB)

  • Can NOT be used against adult pulmonary TB

  • Interferes with TST (PPD)

• Infection control

• Prompt testing

• Consume only pasturized dairy products

Why is mycobacterium leprae so difficult to grow in a lab setting?

It has an extremely long doubling time

What was the first bacterium to be identified as causing disease in humans?

M. leprae

_____________ causes Hansen’s Disease

M. leprae

What two pathogens result in granulomas?

Mtb, M. leprae

True or False: M. leprae thrives in warm temperatures

False (Cooler temps necessary for growth)

Why does M. leprae target peripheral nerves and extremeties?

It prefers cooler areas of the body

What are the effects of untreated Hansen’s disease?

Blindness, crippling of hands and feet, facial disfigurement (especially nose/ear), paralysis

How is M. leprae transmitted?

• Spread person-person (NOT very contagious)

• Transmitted by inhalation or direct contact with broken skin

• Prolonged close contact with an untreated HD patient over months to years is needed for transmisison

Which is more infectious?

Mtb

M. leprae

Mtb

True or False: M. leprae has been found to be zoonotic in some cases

True

Which pathogen invades skin macrophages and Schwann cells?

M. leprae

How is M. leprae treated?

Antibiotics can cure the infection

What are the signs/symptoms of M. leprae disease?

**Symptoms are subtle and occur slowly over years**

• Discolored numb skin patch

• Progressive numbness and loss of temperature

• Without antibiotic treatment:

  • Multiple skin lesions, ulcers, blisters, rashes

  • Eye damage

  • Ear disfigurement

  • Hair loss

  • Nerve damage

  • Severe damage and disfigurement

How is M. leprae diagnosed?

• Hypopigmented or reddish skin patches with loss of sensation

• Thickened peripheral nerves

• AFB (acid fast bacilli) detected on skin smears or biopsy

How is atypical pneumonia differentiated from classic pneumonia

Clinical findings and lack of response to typical antibiotics used for classical pneumonia

Atypical pneumonia is also called ________________.

Walking pneumonia

Which pathogen is too small to be visualized by light microscopy?

M. pneumoniae

(M. pneumoniae/L. pneumophila) lacks a cell wall

M. pneuomoniaw

Why is M. pneumoniae resistant to gram staining and many antimicrobial agents?

No cell wall

What is M. pneuomoniae’s secreted virulence factor?

Production of hydrogen peroxide

What is the reason for the persistant cough in an M. pneumoniae infection?

Hydrogen peroxide’s cytopathic affect to airway epithelium and cilia

How is M. pneumoniae transmitted?

Person to person through respiratory droplets

True or False: Many cases of M. pneumoniae infection are asymptomatic

True

How is an M. pneumoniae infection treated?

• Most people recover on their own

• Pneumonia treated with antibiotics

How can an M. pneumoniae infection be prevented?

• No vaccine

• Same steps of prevention as any respiritory infection

__________ is a non-encapsulated, motile, environmental, Gram-negative bacilli

Legionella pneumophila

What pathogen is a facultaive intracellular parasite (capable of living and reproducing either inside or outside cells)

L. pneumophila

How is L. pneumophila transmitted?

• Inhalation of contaminated aerosols (hot tubs, cooling towers, large plumbing systems, fountains, etc.)

• Person to person is rare

Infection of L. pneumophila begins in the (upper/lower) respiritory tract.

Lower (here is where bacteria multiply intracellularly in alveolar macrophages)

Which is the most severe type of atypical pneumonia?

Legionnaire’s Disease

True or False: If exposed to L. pneumophila you are basically guarenteed to be infected with Legionnaire’s disease.

False (most people do not become ill)

True or False: Legionnaire’s Disease is highly fatal

True

How is Legionnaire’s disease diagnosed?

• Confirmation of pneumonia by chext x-ray

• Urine test for legionella antigens

• Culture of sputum/lung biopsy

• Blood analysis

How is Legionnaire’s Disease treated?

Antibiotics and/or hospitalization to prevent lung failure and death

How is Legionnaire’s Disease prevented?

• Maintenance and cleaning of hot tubs, pools, etc.

• Avoidance of smoking to decrease susceptibilty

What pathogen is responsible for walking pneumonia?

M. pneumoniae

Eukarya branched off of __________.

Archaea

Eukaryotes/prokaryotes are larger in size.

Eukaryotes

True or False: Eukaryotes reproduce through sexual reproduction only

False (Sexual and/or asexual)

Eukaryotes have multiple __________ genomes.

linear

What is the defining feature of eukaryotes?

A nucleus and membrane bound organelles

Explain the theory of endosymbiosis:

• anaerobic archaeal host cell engulfed an aerobic bacterium (non-photosynthetic)

• Instead of digesting it, the host and the bacterium formed a symbiotic relationship

• The bacterium provided efficient energy (ATP) via respiration, while the host provided nutrients and safety. This symbiont eventually evolved into the mitochondrion

• Then, another symbiotic event happened when a eukaryote engulfed a cyanobacteria which evolved into chloroplasts (photosynthetic)

The cell wall of fungi is made up of ______ and ________.

Chitin, Glucan

__________ and __________ branches of eukaryotes can be unicellular

Fungi, protists

_________, _________, and ___________ branches of eukaryotes can be multicellular

Fungi, plants, animals

The cell wall of plant cells is made up of __________.

Cellulose

True or False: Plants can be pathogenic to humans

False

Which branch of the eukaryotic kingdom lacks a cell wall?

Animal

Photosynthetic protists = __________

Algae

Non-photosynthetic protists= _____________

Protozoans

True or False: Fungi can be pathogenic to humans

True

True or False: Protists can be pathogenic to humans

True

Which two organelles within a eukaryotic cell are not membrane bound?

• Ribosomes

• Cytoskeleton

Eukaryotic organelle that works as the protein factory

Ribosomes

Ribosomes are made of _________ and _________

Proteins and rRNA

Eukaryotic organelle that is a dynamic and responsive intracellular network of protein fibers.

Cytoskeleton

Which eukaryotic structure

• maintains shape and mechanically resists/allows deformation

• holds organelles in place

• facilitates movement

• etc.

Cytoskeleton

The _________ houses the DNA genome within __________ in a eukaryotic cell.

nucleus, nucleoplasm

Complex of DNA and proteins

Chromatin

Dense region of rRNA biosynthesis where ribosome assembly begins

Nucleolus

Mitosis= (sexual/asexual) reproduction

Meiosis= (sexual/asexual) reproduction

asexual, sexual

Series of membranous tubules, sacs, and flattened disks (cisternae) that synthesize many cell components and move materials within the cell

Endomembrane system

Which 3 organelles are involved in the endomembrane system?

• Endoplasmic reticulum

• Golgi apparatus

• Vescicles/Vacuoles

What makes an endoplasmic reticulum “rough” vs. “smooth”

The presence of ribosomes (making “bumps”)

Which eukaryotic organelle sorts and distributes final products using transport vesicles?

Golgi apparatus

Aside form sorting and distribution, what is the other role of the golgi apparatus?

Modifying lipids and proteins transported from the ER (adds carbohydrates)

__________ transport, secrete, digest, and sequester materials.

Vesicles

___________ are small fluid-filled, lipid bilayer enclosed, spherical sacs

Vesicles

Which eukaryotic organelle is responsible for exocytosis?

Vesicles

Typically larger than vesicles, often used for storage

Vacuoles

Which degradative vesicles are considered “cellular garbage disposals”? These break down particles in a compartmentalized fashion to avoid collateral damage.

Lysosomes

Which degradative vesicle is responsible for oxidative degradation?

Peroxisomes

Mitochondrial DNA is (linear/circular)

circular

True or False: Eukaryotic cells produce peptidoglycan

False (only bacteria)

What provides stability to a eukartotic cell membrane?

Sterols (Animal=cholesterol, Fungi=ergosterol)

True or False: The plasma membrane of a eukaryotic cell uses simple diffusion, facilitated diffusion, and active transport.

True

(Endocytosis/Exocytosis) is the process of importing into the cell

Endocytosis

Cell-drinking (little materials)

Pinocytosis

Targeted cell uptake in endocytosis

Receptor-mediated