Antibiotic Resistance and Immunology Quiz
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Which of the following is NOT a mechanism of antibiotic resistance?

  • Enzymatic inactivation of antibiotics
  • Active immunization (correct)
  • Target bypass
  • Horizontal gene transfer

    • What is the primary reason antivirals are often less effective than antibiotics?

  • Viruses are too small for antivirals to target.
  • Viruses have multiple proteins that can be targeted by antivirals.
  • Viruses mutate rapidly, making it difficult to develop effective antivirals.
  • Viruses utilize host enzymes, which can also be targeted by antivirals. (correct)

    • Which of the following is an example of an inactivated viral vaccine?

  • Varicella
  • Hepatitis B
  • Measles
  • Polio (injected) (correct)

    • Aminoglycoside-modifying enzymes (AMEs) are a type of resistance mechanism that primarily affects which process?

    <p>Protein synthesis</p> Signup and view all the answers

    Which of the following statements is true about active immunization?

    <p>Active immunization aims to prevent the initiation of disease.</p> Signup and view all the answers

    Which of the following is a characteristic of multi-drug resistant transporters (MDRs)?

    <p>They block antibiotic access to bacterial cells.</p> Signup and view all the answers

    Which statement BEST describes the use of bacteriophages as a potential treatment against bacterial infections?

    <p>Bacteriophages are being re-examined as a treatment option due to the rise of antibiotic resistance.</p> Signup and view all the answers

    Which of the following is NOT a contributing factor to the rise of antibiotic resistance?

    <p>The development of new antibiotics</p> Signup and view all the answers

    What is the most common parasitic infection worldwide?

    <p>Malaria</p> Signup and view all the answers

    How do parasites cause tissue damage?

    <p>By releasing enzymes that break down the surrounding extracellular matrix</p> Signup and view all the answers

    Which of the following is an example of an intracellular parasitic infection?

    <p>A liver infection caused by the malaria parasite</p> Signup and view all the answers

    What is the basic structure of a virus called?

    <p>Virion</p> Signup and view all the answers

    What type of nucleic acid is present in the virion of a virus?

    <p>Ribonucleic Acid (RNA)</p> Signup and view all the answers

    How do parasites block the immune response?

    <p>By directly attacking immune cells</p> Signup and view all the answers

    What are the potential outcomes of a parasitic infection?

    <p>A combination of the above</p> Signup and view all the answers

    How can parasitic infections be transmitted?

    <p>All of the above</p> Signup and view all the answers

    What is the primary disease caused by fungi?

    <p>Mycosis</p> Signup and view all the answers

    Which organism was reclassified as a fungus?

    <p>Pneumocystis carinii</p> Signup and view all the answers

    What can cause systemic fungal infections?

    <p>Immunosuppression</p> Signup and view all the answers

    Which fungal infection remains localized if the immune system is intact?

    <p>Candida albicans</p> Signup and view all the answers

    How do fungi evade phagocytosis?

    <p>By altering antigen expression</p> Signup and view all the answers

    Which of the following is NOT a common route of transmission for parasitic infections?

    <p>Human to human contact</p> Signup and view all the answers

    What type of organism is Toxoplasma gondii?

    <p>Protozoan</p> Signup and view all the answers

    Which of the following is a factor that facilitates the survival of fungi in the host?

    <p>Alkaline pH levels</p> Signup and view all the answers

    What is the main method by which virions enter respiratory epithelial cells?

    <p>Endocytosis</p> Signup and view all the answers

    What are the two kinds of HIV viruses associated with AIDS?

    <p>HIV-1 and HIV-2</p> Signup and view all the answers

    What is not a route of transmission for HIV?

    <p>Airborne particles</p> Signup and view all the answers

    What is the role of reverse transcriptase in HIV?

    <p>To create a double-stranded DNA version of the virus</p> Signup and view all the answers

    What term describes the change in surface proteins of viruses that occurs each year?

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

    What impact does HIV have on the body's immune system?

    <p>It depletes the body's T helper cells</p> Signup and view all the answers

    What is the epicenter of the AIDS pandemic?

    <p>Africa</p> Signup and view all the answers

    What can result from the integration of HIV's DNA into a host cell?

    <p>Increased apoptosis and shedding of infectious HIV</p> Signup and view all the answers

    What is the term for the period from initial exposure to the onset of first symptoms?

    <p>Incubation</p> Signup and view all the answers

    Which phase of clinical infectious diseases is characterized by the occurrence of initial mild symptoms?

    <p>Prodromal</p> Signup and view all the answers

    Which factor primarily influences the likelihood of infection, according to the text?

    <p>An adequate number of microorganisms</p> Signup and view all the answers

    What type of pathogens are described as being able to bypass normal defenses?

    <p>True pathogens</p> Signup and view all the answers

    In which transmission type do microorganisms spread through intermediate filters like insects or water?

    <p>Indirect transmission</p> Signup and view all the answers

    What essential functions do resident microorganisms perform in the human body?

    <p>Aid in digestion and produce metabolites</p> Signup and view all the answers

    Which phase follows the invasion of microorganisms into surrounding tissues?

    <p>Convalescence</p> Signup and view all the answers

    What role do specific surface receptors play in the colonization of microorganisms?

    <p>They help microorganisms adhere to tissues</p> Signup and view all the answers

    What type of bacteria do not retain crystal violet dye during the Gram staining process?

    <p>Gram-negative bacteria</p> Signup and view all the answers

    Which of the following is a characteristic of Staphylococcus aureus?

    <p>Major cause of hospital-acquired infections</p> Signup and view all the answers

    What are exotoxins primarily responsible for?

    <p>Inhibiting protein synthesis</p> Signup and view all the answers

    Which bacteria are considered intracellular parasites with complex life cycles?

    <p>Chlamydia</p> Signup and view all the answers

    What is a characteristic of Gram-positive bacteria?

    <p>Retain crystal violet dye during Gram staining</p> Signup and view all the answers

    Which of the following statements best describes endotoxins?

    <p>They activate inflammation and can cause fever</p> Signup and view all the answers

    What is the main action of superantigens in relation to the immune system?

    <p>They degrade immune cells</p> Signup and view all the answers

    The smallest and simplest type of bacteria are known as?

    <p>Mycoplasma</p> Signup and view all the answers

    Study Notes

    Chapter 10: Infection

    • Infectious disease is a major cause of death and morbidity. This is due to reemerging older infections, newly discovered infections, and infections that have become resistant to multiple antibiotics.
    • More than 40 unknown infections have emerged in a single generation.

    Microorganism and Humans: A Dynamic Relationship

    • Microorganisms and humans have a mutual symbiotic relationship, meaning both benefit from a relationship.
    • Normal microflora are found in various parts of the body.
    • They produce enzymes that aid in digestion.
    • Produce antibacterial factors to prevent colonization by pathogens
    • Produce metabolites, such as Vitamin K and B vitamins.

    Clinical Infectious Disease

    • Incubation: The period between initial exposure and the onset of symptoms, and can last for hours to years.
    • Prodromal: The initial symptoms are typically mild and include feelings of discomfort and tiredness.
    • Invasion: Infection spreads to other areas of the body.
    • Convalescence: The recovery period, where symptoms subside, the infection is fatal or there is a period of latency.

    Clinical Infectious Diseases (Continued)

    • True pathogens bypass normal defenses to cause infection; infection happens when the number microorganisms is sufficient, not necessarily because the host's defenses are compromised.
    • Colonization is when infectious microorganisms reside in reservoirs like contaminated soil, water, or other animals or humans.
    • Transmission types include direct and indirect (vectors). Types of transmission include droplet, airborne, vertical, and horizontal.
    • Microorganisms adhere to tissue using receptors.

    Clinical Infectious Diseases (Continued)

    • Invasion: Invade surrounding tissue by evading the host's defenses.
    • Multiplication: Microorganisms multiply rapidly in the warm and nutrient-rich environment of human tissue.
    • Some pathogens (viruses/bacteria) replicate inside infected cells.
    • Spread: Infection might stay limited or spread to other areas, especially if the immune system is compromised.

    Clinical Infectious Disease Question 1

    • The symptoms of mild tiredness and discomfort after exposure to the flu are characteristic of the prodromal period.

    Clinical Manifestations of Infectious Disease

    • Symptoms vary, dependent on the pathogen; symptoms may exist whether pathogen or its products directly cause them.
    • Manifestations may include fatigue, malaise, weakness, loss of concentration, aching, and appetite loss.
    • Fever is a hallmark of infection as the body temperature is raised above normal. It's caused by exogenous and endogenous pyrogens.

    Factors Affecting Disease Development

    • Communicability: The ability of a pathogen to spread.
    • Immunogenicity: The ability of a pathogen to trigger an immune response.
    • Infectivity: The ability to invade and multiply within the host.
    • Mechanism of action: How microorganisms damage the tissue.
    • Pathogenicity: The ability to produce disease.
    • Portal of entry: How organisms enter the body.
    • Toxigenicity: Production of toxins.
    • Virulence: The capacity to cause serious illness; its potency.

    Infectious Disease Classification

    • Endemic: Diseases with relatively high, but constant, rates of infection within a certain population.
    • Epidemic: A substantial increase in the number of infections—higher than would be expected.
    • Pandemic: An epidemic that spreads over a vast area, such as a continent or the entire world.

    Classes of Infectious Microorganisms

    • Bacteria, Fungi, Parasites, Protozoa, Viruses

    Bacterial Infections

    • True bacteria: Reproduce via binary fission.
    • Filamentous bacteria: Have branching, mycelium-like structures.
    • Spirochetes: Flexible and spiral-shaped, usually anaerobic.
    • Mycoplasmas: Simplest bacteria.
    • Rickettsiae: Intracellular parasites.
    • Chlamydiae: Intracellular parasites with intricate life cycles.

    Bacterial Infections (Continued)

    • Gram-negative bacteria: Do not retain crystal violet dye.
    • Gram-positive bacteria: Retain crystal violet dye.
    • Gram-negative bacteria have a lipopolysaccharide coat (called endotoxin)
    • Gram-positive bacteria have a peptidoglycan coat
    • Exotoxins: Enzymes released during bacterial growth. They damage cell membranes, activate second messengers and inhibit protein synthesis.
    • Endotoxins: Components of gram-negative bacteria cell walls. Released during bacterial lysis. They are pyrogenic (cause fever) and trigger inflammation.

    Bacterial Infections (Continued)

    • Produce toxins and extracellular enzymes to destroy or incapacitate phagocytic cells.
    • Coat the antibody fragment, preventing complement activation and phagocytosis.
    • Degrade immune cells.
    • Bind and neutralize antibodies.
    • Evade complement.
    • Cause immune suppression.
    • Resistant: Alter surface molecules that express antigens.

    Bacterial Infections (Continued)

    • Tissue damage from bacterial products (toxins) or from inflammation.
    • Superantigens are toxins that cause intense, widespread inflammatory reactions.
    • Endotoxic shock is a serious systemic reaction caused by endotoxins.
    • S. aureus (staphylococcus aureus) is a major cause of hospital-acquired infections and antibiotic resistance (e.g., MRSA).
    • β-lactamases are enzymes that break down penicillin. More recently developed is methicillin-resistance S. aureus.

    Fungal Infections

    • Large with thick, rigid cell walls.
    • Types include mold, yeast, and dimorphic microorganisms.
    • Fungal infections are called mycoses.
    • Infections can occur via inhalation or contamination of wounds.
    • Dermatophytes are fungi that infect skin, hair or nails.

    Fungal Infections (Continued)

    • Molds: Are filamentous fungi that grow as multinucleate, branching hyphae, forming a mycelium (e.g., ringworm).
    • Yeasts: Grow as spherical cells that multiply by budding (example: Histoplasma).
    • Systemic infection usually results from immunosuppression.
    • Pneumocystis jiroveci was formerly Pneumocystis carinii.
    • Fungi's adapt to the host environment by existing in a wide temperature ranges, hypoxic conditions and alkaline pH.
    • They suppress the immune defenses.
    • Fungi survive in the phagosome or inhibit lysosomal enzymes.
    • Damage from fungal enzymes and indirectly by inflammation.

    Fungal Infections (Continued)

    • Candida albicans is the most prevalent fungal infection found in skin, GI tract, mouth, and vagina.
    • Local defense mechanisms within skin flora and microbiome contribute to antifungal action.
    • Infection remains localized if the immune system is intact. However, widespread infection can occur when the immune system is compromised.

    Parasitic and Protozoan Infections

    • Parasites range from unicellular protozoa to large worms (helminths).
    • Intestinal and tissue nematodes (e.g. hookworm, roundworm)
    • Flatworms (e.g liver fluke, lung fluke, tapeworm).
    • Common parasitic infections in the US include Toxoplasma gondii and Trichomonas vaginalis.

    Parasitic and Protozoan Infections (Continued)

    • Not typically transmitted human-to-human, but often through vectors (e.g. malaria by mosquito bites, trypanosomes by tsetse fly, Leishmania spp. by sand fleas).
    • Includes other infections from water or food (e.g. Giardia lamblia).

    Parasite Invasion

    • Extracellular: Parasites invade the GI tract, vagina, or skin through bites.
    • Intracellular: Parasites enter the body via ingested contaminated food or water, or from bites from vectors.
    • Tissue damage from parasites results from release of enzymes that degrade surrounding tissues.

    Response to Parasitic Infection

    • Individuals mount an immune/inflammatory response.
    • Physical loss of tissue or organ (potentially).
    • Immune hypersensitivity reactions can occur.

    Parasite Blocking of Immune Response

    • Antibody-mediated complement activation is effective against some parasites.
    • Pathogen-specific and nonspecific immune suppression occurs.

    Malaria

    • Worldwide infection transmitted via anopheles mosquito bite.
    • Parasites invade the liver parenchymal cells.
    • After multiple rounds of division, disrupted cells release parasites that infect RBCs.

    Parasitic and Protozoan Infections Question 2

    • Malaria is a common parasitic infection.

    Infectious Viruses

    • Basic structure of a virus is a nucleic acid surrounded by protein (capsid).
    • Classified by nucleic acid (RNA or DNA), whether it is single- or double-stranded, and if it uses reverse transcriptase.
    • Viruses are the most common human affliction, including the common cold, cold sores, hepatitis, HIV, and various cancers.

    Infectious Viruses (Continued)

    • Viruses are intracellular parasites.
    • Viruses bind to host cells with receptors.
    • Viruses enter host cells, releasing genetic information.
    • RNA viruses enter host nucleus and manufacture mRNA.
    • DNA viruses enter host nucleus and may integrate into host DNA.

    Infectious Viruses (Continued)

    • mRNA translation makes viral proteins.
    • Enveloped viruses release new virions by budding.
    • Viral DNA integrates into host cells and replicates through mitosis.

    Infectious Viruses (Continued)

    • Enveloped viruses bind to receptors, fuse with host cells, releasing nucleic acid into cytoplasm.

    Infectious Viruses (Continued)

    • Viruses rarely produce toxins; symptoms are often mild (fever, aches, nausea).
    • Some viruses proliferate rapidly (norovirus, rotavirus, Ebola, Marburg, hantavirus).
    • Interferons are effective against many viruses.
    • Viruses are sensitive to complement activation.

    Infectious Viruses (Continued)

    • Harmful effects may include inhibiting DNA/RNA/protein synthesis, disrupting lysosomal membranes, promoting apoptosis, fusing adjacent cells (giant cells), transforming into cancer cells, altering antigenic properties (causing immune attacks).

    Infectious Viruses (Continued)

    • Influenza is highly infectious via respiratory epithelial cell entry and endocytosis.
    • It can be fatal to young and old and is seasonal.
    • Surface proteins (antigens) change each year, which results in antigenic drift/mutation.
    • Antigenic shift arises from genetic recombination of different viral species.

    Acquired Immunodeficiency Syndrome (AIDS)

    • AIDS is caused by HIV, which depletes Th cells and increases susceptibility to infections and cancer.
    • Worldwide problem; Africa is the epicenter.
    • In 2014, 21,000 new cases of AIDS were reported in the United States.
    • Millions have died from AIDS since 1980s.

    Acquired Immunodeficiency Syndrome (AIDS) (Continued)

    • HIV is a bloodborne pathogen present in fluids like blood, vaginal fluid, semen, and breast milk.
    • HIV transmission routes include blood/blood products, IV drug use, and heterosexual/homosexual activity, as well as maternal-child transmission.
    • HIV is a retrovirus.

    Acquired Immunodeficiency Syndrome (AIDS) (Continued)

    • HIV has RNA genetic material, with reverse transcriptase to create dsDNA.
    • Integrase inserts viral DNA into host cells, resulting potentially dormant or active states of the virus.
    • Actively replicating the virus may cause host cell apoptosis.

    Acquired Immunodeficiency Syndrome (AIDS) (Continued)

    • HIV infections initially may not show symptoms (serologically negative/positive asymptomatic/early stages/window periods).
    • Early AIDS may present with symptoms like fatigue, headache, muscle aches, and fever.
    • Some may be asymptomatic for years.

    Acquired Immunodeficiency Syndrome (AIDS) (Continued)

    • Diagnosis involves a variety of lab tests and clinical observations, including atypical infections or cancer symptoms and CD4+ T-cell counts.

    Acquired Immunodeficiency Syndrome (AIDS) (Continued)

    • Antiretroviral therapy aims to inhibit HIV from replicating but not always cure the infection.
    • It involves using three or more medications to target different stages of HIV replication, typically at least two drugs that inhibit reverse transcriptase and one from a different class of drugs.

    Pediatric Acquired Immunodeficiency Syndrome

    • Testing HIV antibodies in infants is often limited by passive maternal antibodies at 18 months.
    • The CNS is vulnerable to HIV with potential symptoms such as developmental delays, loss of intellectual abilities, impaired brain growth, or microcephaly, or motor deficits.

    SARS-CoV-2

    • Link to video on structure and pathogenesis of SARS-CoV-2 available.

    Countermeasures Against Pathogens

    • Enviromental infection control is used to prevent infections to limit spread.
    • Antimicrobials prevent growth (bacteriostatic) or directly kill (bactericidal) microorganisms.
    • Antimicrobials may inhibit cell wall production/DNA replication/protein synthesis or interfere with folic acid metabolism.
    • Antimicrobials may cause resistance in microorganisms.
    • Antivirals are less successful than other antimicrobials because viruses often use the host cell's enzymes.

    Countermeasures Against Pathogens (Continued)

    • Antibiotic Resistance is important because of the Horizontal Gene Transfer or HGT.
    • The Horizontal Gene Transfer of antibiotics leads to rapid increase of the microorganisms through the process of genetic exchange.
    • Other methods used for resistance inactivation include enzymatic inactivation, amino glycoside-modifying enzymes (AMEs), multidrug resistant transporting (MDRs).
    • An alternative method is to use target bypass by using proteins that prevent access of antibiotics.
    • Methicillin-resistant S. aureus (MRSA) is a major public health concern due to antibiotic resistance.

    Countermeasures Against Pathogens (Continued)

    • Active Immunization: Vaccines are used to prevent disease initiation and create immunity; boosters are often required. Vaccines include attenuated (weakened) and inactivated (killed) virus vaccines for measles, mumps, rubella (MMR), varicella, influenza, polio, rotavirus, hepatitis A and B, and recombinant vaccines (HPV, Hep B).

    Countermeasures Against Pathogens (Continued)

    • Bacterial vaccines include conjugated vaccines (to carrier proteins with a boosted immunogenicity through proteins like Haemophilus influenzae type B [Hib]), and toxoids (vaccines against bacterial toxins like tetanus and diphtheria).
    • Other examples include extracted capsular polysaccharides from dead bacteria such as pneumococcal and meningococcal

    Countermeasures Against Pathogens Question 4

    • One of the actions of antibiotics is to inhibit protein synthesis.

    Countermeasures Against Pathogens

    • Preformed antibodies are administered to individuals to prevent infections using passive immunotherapy.
    • Passive immunotherapy is useful for infections like hepatitis A and B, Ebola, and rabies.

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    Chapter 10 Infection PDF Lecture Notes

    Description

    Test your knowledge on antibiotic resistance mechanisms, the effectiveness of antivirals compared to antibiotics, and the characteristics of vaccines. This quiz covers various aspects of immunology, including the role of bacteriophages and parasitic infections.

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