Multi-Drug Resistant TB and Influenza Virus
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Questions and Answers

What is the main role of Hip1 in relation to proinflammatory cytokines?

  • It promotes T cell maturation.
  • It improves antigen presentation.
  • It impairs cytokine production. (correct)
  • It enhances cytokine production.

    • What characterizes Multi-Drug Resistant TB (MDR-TB)?

  • Sensitivity to all first-line TB drugs.
  • Caused by non-virulent strains of M.tuberculosis.
  • Resistance to isoniazid and rifampin. (correct)
  • Resistance to only one first-line drug.

    • Which component of the mycobacterial cell wall provides protection against chemical damage?

  • Outer membrane proteins.
  • Peptidoglycan.
  • Mycolic acid. (correct)
  • Arabinogalactan.

    • What is required for curing an MDR-TB infection?

    <p>A combination of second-line drugs.</p> Signup and view all the answers

    What is the hydrophobic aspect of mycobacterial cell walls attributed to?

    <p>Mycolic acid.</p> Signup and view all the answers

    Which of the following roles does the mycobacterial outer membrane NOT perform?

    <p>Facilitating antigen presentation.</p> Signup and view all the answers

    How does the structure of the mycobacterial cell wall affect its immune response?

    <p>It prevents T cell responses.</p> Signup and view all the answers

    What is a unique feature of the mycobacterial outer membrane?

    <p>It contains mycolic acid.</p> Signup and view all the answers

    What role do fimbriae play in the pathogenesis of ETEC?

    <p>They facilitate the attachment of bacteria to the small intestine.</p> Signup and view all the answers

    What is the effect of E. coli labile toxins on intestinal cells?

    <p>They promote massive secretion of water and salts into the intestine.</p> Signup and view all the answers

    How does poliovirus enter host cells?

    <p>Through interaction with the CD155 receptor.</p> Signup and view all the answers

    What must be made for poliovirus to replicate its genome?

    <p>A complementary strand of negative-sense RNA.</p> Signup and view all the answers

    Which enzyme is critical for RNA viruses like poliovirus to replicate their genomes?

    <p>RNA-dependent RNA polymerase.</p> Signup and view all the answers

    What is one effective treatment for acute dehydration caused by ETEC infection?

    <p>Isotonic salt solutions.</p> Signup and view all the answers

    How is poliovirus RNA translated into proteins within the host cell?

    <p>As if it were messenger RNA.</p> Signup and view all the answers

    What structure does the E. coli labile toxin resemble in effect?

    <p>Cholera toxin.</p> Signup and view all the answers

    What is the main cause of Staphylococcus scalded skin syndrome?

    <p>Exfolitin toxin from certain strains of Staphylococcus</p> Signup and view all the answers

    Which demographic is most commonly affected by erysipelas?

    <p>Very young children and elderly individuals</p> Signup and view all the answers

    What is the primary pathogen associated with folliculitis?

    <p>Staphylococcus aureus</p> Signup and view all the answers

    What characterizes necrotizing fasciitis?

    <p>Involvement of superficial fascia and subcutaneous fat</p> Signup and view all the answers

    What is a common treatment for acne vulgaris?

    <p>Antibacterials or retinol</p> Signup and view all the answers

    What symptom is typically associated with furuncles and carbuncles?

    <p>Chills and fever</p> Signup and view all the answers

    Which condition is a superficial skin infection that is self-limiting and does not result in scarring?

    <p>Epidermal infections</p> Signup and view all the answers

    Which organism is commonly linked to cellulitis in the context of marine environments?

    <p>Vibrio vulnificans</p> Signup and view all the answers

    What primarily stimulates the overproduction of sebum in acne vulgaris?

    <p>Hormonal activity</p> Signup and view all the answers

    What is the typical appearance of lesions associated with erysipelas?

    <p>Bright red lesions</p> Signup and view all the answers

    What type of virus causes significant disease in humans?

    <p>Influenza virus</p> Signup and view all the answers

    What mechanism allows influenza strains to evolve and adapt over time?

    <p>Antigenic drift</p> Signup and view all the answers

    Which symptoms are commonly associated with upper respiratory tract infections caused by influenza?

    <p>Nasal stuffiness and runny nose</p> Signup and view all the answers

    What role does hemagglutinin (HA) play in the life cycle of the influenza virus?

    <p>It binds to epithelial cells</p> Signup and view all the answers

    Which term describes the occasional reassortment of genes that can lead to new influenza viruses?

    <p>Gene reassortment</p> Signup and view all the answers

    How are neuraminidase inhibitors utilized in the treatment of influenza?

    <p>They block the virus's ability to cleave sialic acid</p> Signup and view all the answers

    When is the use of neuraminidase inhibitors most effective?

    <p>Within 48 hours of symptom appearance</p> Signup and view all the answers

    What complications can arise due to influenza infections?

    <p>Pneumonia and bronchitis</p> Signup and view all the answers

    What is the primary structure responsible for the synthesis of mRNA in the influenza virus?

    <p>Polymerase proteins</p> Signup and view all the answers

    Which of the following features of influenza virus contributes to its seasonal outbreaks?

    <p>Environmental factors like humidity</p> Signup and view all the answers

    What is a characteristic of live attenuated influenza vaccine delivery?

    <p>It is delivered by nasal spray</p> Signup and view all the answers

    What is the expected duration for most influenza infections to resolve without intervention?

    <p>2 weeks</p> Signup and view all the answers

    What immune response can cytokine production during influenza infection negatively impact?

    <p>Integrity of respiratory epithelium</p> Signup and view all the answers

    How is the influenza vaccine composition determined each year?

    <p>According to dominant flu strains in the population</p> Signup and view all the answers

    What mechanism allows norovirus to escape immune recognition and facilitate reinfection?

    <p>Antigen variation</p> Signup and view all the answers

    Which of the following accurately describes the infectious nature of norovirus?

    <p>Highly infectious with a low infectious dose</p> Signup and view all the answers

    What role does the viroporin NSP4 play in rotavirus infection?

    <p>Regulates chloride channels leading to water loss</p> Signup and view all the answers

    Which immune cells can norovirus infect during its pathogenesis?

    <p>B lymphocytes and macrophages</p> Signup and view all the answers

    What type of virus is poliovirus characterized as?

    <p>Non-enveloped, icosahedral capsid containing single-stranded RNA</p> Signup and view all the answers

    What is the primary route of transmission for poliovirus?

    <p>Faecal-oral route</p> Signup and view all the answers

    How does norovirus cause damage to the intestinal lining?

    <p>By mechanically attaching and damaging the epithelial layer</p> Signup and view all the answers

    Which of the following is NOT a characteristic of rotavirus infections?

    <p>Causes inflammation and severe immune response</p> Signup and view all the answers

    Why are norovirus outbreaks often seen in crowded environments?

    <p>High rate of asymptomatic carriers</p> Signup and view all the answers

    What is one consequence of faecal contamination found in norovirus outbreaks?

    <p>Variation of strain-specific immunity duration</p> Signup and view all the answers

    Which feature of poliovirus allows for its transmission even on contaminated surfaces?

    <p>Persistence in the environment</p> Signup and view all the answers

    What is the incubation period for norovirus after exposure?

    <p>24-48 hours</p> Signup and view all the answers

    Which of the following contributes to rotavirus's ability to increase intestinal motility?

    <p>Effects on enteric neurons</p> Signup and view all the answers

    What vaccine strain is used for poliovirus immunization?

    <p>Live-attenuated Sabin vaccine</p> Signup and view all the answers

    Study Notes

    Multi-Drug Resistant TB (MDR-TB)

    • MDR-TB occurs when a Mycobacterium tuberculosis strain is resistant to isoniazid and rifampin, two of the most powerful first-line TB drugs.
    • To treat MDR-TB, a combination of second-line drugs is used.

    Influenza Virus

    • The genome is segmented, negative-sense, single-stranded RNA.
    • The virus causes significant disease in humans.
    • Antigenic drift occurs when viral polymerase makes mistakes when replicating, leading to small changes in viral epitopes that accumulate over time.
    • Antigenic shift occurs when a virus arises with gene segments derived from multiple different types of influenza virus (e.g., combining human, bird, swine strains).
    • Hemagglutinin (HA) binds to epithelial cells of the upper tract via sialylated glycans.
    • PB1-F2 induces host cell apoptosis and impairs type 1 IFN production.
    • Neuraminidase inhibitors are structural mimics of sialic acid that are effective against IAV and IBV if used within 48 hours of the appearance of symptoms.
    • Live attenuated influenza virus vaccine is delivered by nasal spray.
    • Inactivated influenza vaccine is composed of two IAV and two IBV strains and is delivered by intramuscular injection.

    Norovirus

    • It lacks durable immunity, with strain-specific immunity lasting only a few weeks after infection.
    • It has a short incubation period (24-48 hours).
    • It is persistent, with fecal shedding lasting up to 60 days.
    • Capsids bind to histo-blood group antigens (HBGA) on the surface of mucosal epithelial cells.
    • The virus can infect macrophages, dendritic cells, B lymphocytes, and the lamina propria of the small intestine.
    • Viral NTPase inhibits the production of IFN-beta during infection.
    • Antigen variation facilitates immune escape and reinfection.

    Rotavirus

    • Viroporin NSP4 (viral enterotoxin) acts on chloride channels to induce water loss.
    • NSP4 also regulates calcium homeostasis to favor viral replication.
    • NSP4 acts on enteric neurons to increase intestinal motility.
    • Infection occurs in the enterocytes of the small intestine.
    • The infection is non-inflammatory.

    Poliovirus

    • 2B protein (viroporin) alters membrane permeability of infected cells to increase release of new virions.
    • Live-attenuated Sabin vaccine contains a mutation in the 5’ non-coding section of the RNA genome.
    • The virus attaches and enters host cells by interacting with host cell CD155 receptor (also known as poliovirus receptor or PVR).
    • Poliovirus replication utilizes host cell ribosomes to translate the positive-sense RNA genome into proteins.
    • The virus must encode its own RNA-dependent RNA polymerase (RdRp) in order to replicate its genome.

    Enterotoxigenic Escherichia coli (ETEC)

    • Fimbriae attach to the intestinal epithelial cell wall.
    • Fimbriae act as adhesins, binding to specific molecules on the epithelial cell surface.
    • Fimbriae help ETEC avoid being washed away by the rapid flow of food.
    • ETEC produce labile toxins.
      • The toxin can be produced in food and ingested or after host colonization.
      • The toxin is similar in structure and effect to cholera toxin.
      • It attaches to the surface of the small intestinal epithelial cell.
      • It disrupts ion and water flow across the membrane.
      • It causes massive secretion of water and salts into the lumen of the intestine.
      • In acute cases, salt and fluid loss leads to dehydration and death.
    • Rehydration therapy (isotonic salt solutions) is very effective.

    Staphylococcus Aureus Infections

    • Can be a polymicrobial infection, involving multiple microbes
    • Infections are superficial and do not scar
    • There is no significant immune response
    • Infections resolve spontaneously or with antibiotic treatment

    Epidermis

    • Staphylococcus Scalded Skin Syndrome (Ritter's Disease) is caused by the toxin exfoliatin, produced by certain Staphylococcus strains
    • Occurs mainly in young children
    • Spontaneous recovery usually happens within 7-10 days without scarring
    • Secondary bacterial infections can lead to more serious complications

    Dermis

    • Erysipelas is usually caused by Streptococcus pyogenes
    • Most common in young children and elderly individuals, as their immune systems are developing or declining
    • Characterized by bright red lesions due to an immune reaction
    • Treatment involves antibiotics effective against Streptococcus

    Dermis Appendages

    • Acne Vulgaris is prevalent in adolescence when the endocrine system is highly active

    • Hormonal activity stimulates overproduction of sebum by oil glands, promoting Propionibacterium acnes growth

    • Inflammation leads to the formation of comedones (plugs of sebum and keratin in oil gland ducts), causing pimples and blackheads

    • Treatment includes antibacterials, antibiotics, and retinol to reduce oil gland function

    • Folliculitis involves infection and inflammation of the hair follicle

    • Staphylococcus aureus is the most common cause

    • When occurring on the eyelid, it is called a stye

    Dermis and Appendages

    • Furuncles (boils) are extensions of folliculitis.
    • Carbuncles result from the coalescence of multiple furuncles
    • Chills and fever associated with carbuncles indicate systemic spread of Staphylococcus

    Deep Dermis and Subcutaneous Fat

    • Cellulitis originates from superficial skin lesions or trauma
    • Characterized by hot, red lesions, chills and fever
    • Strep pyogenes is the most common cause, followed by Staph aureus
    • Vibrio vulnificans, a marine microorganism, can cause cellulitis after a wound injury in saltwater
    • Rapid diagnosis and treatment are crucial due to the fast progression of this infection

    Superficial Fascia

    • Necrotizing Fasciitis affects the superficial fascia and subcutaneous fat
    • Undermining of surrounding tissue leads to patchy anesthesia or gangrene
    • There are two main causes, only one is described in the text:
      • One cause involves a rapid spread of infection, primarily due to Streptococcus pyogenes
      • This cause involves a more delayed spread, commonly caused by Staphylococcus aureus
      • This form causes a destructive spreading infection involving the deeper tissues and is sometimes referred to as "flesh-eating bacteria"

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    Description

    Explore the complexities of Multi-Drug Resistant Tuberculosis (MDR-TB) and the Influenza virus. This quiz covers key concepts such as the resistance mechanisms of MDR-TB, antigenic drift and shift in influenza, and the structural aspects of viral proteins. Test your understanding of these critical topics in infectious diseases.

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