Microbiology and Infection Quiz
45 Questions
0 Views

Choose a study mode

Play Quiz
Study Flashcards
Spaced Repetition
Chat to lesson

Podcast

Play an AI-generated podcast conversation about this lesson

Questions and Answers

Which of the following is NOT a major type of pathogen?

  • Viruses
  • Fungi
  • Bacteria
  • Protozoa (correct)

    • What is the term used to describe a balance between a host and a microorganism where the microorganism does not cause disease?

  • Transmission
  • Colonization (correct)
  • Infection
  • Susceptibility

    • Which of the following is an example of direct transmission of infection?

  • Drinking water contaminated with bacteria
  • Being bitten by an infected mosquito
  • Touching a contaminated doorknob
  • Inhaling airborne droplets from a cough (correct)

    • What is the term used to describe an inanimate object that can transmit a pathogen?

    <p>Fomite (A)</p> Signup and view all the answers

    Which of the following factors can make an individual more susceptible to infection?

    <p>Chronic stress (C)</p> Signup and view all the answers

    How do epithelial cells of the skin provide protection from microorganisms?

    <p>They provide multiple layers of protection, especially when dry, as microorganisms prefer moist environments. (A)</p> Signup and view all the answers

    What is the role of lysozyme in the body's defense mechanisms?

    <p>It destroys bacterial cell walls, preventing their growth and spread. (D)</p> Signup and view all the answers

    Which of the following is NOT a chemical barrier that helps to protect the body from infection?

    <p>Mucous membranes (D)</p> Signup and view all the answers

    What is the primary goal of immunization?

    <p>To reduce the susceptibility of a population to a specific pathogen. (D)</p> Signup and view all the answers

    How can a urinary catheter increase the risk of infection?

    <p>It prevents the urine from flushing bacteria out of the urinary tract. (D)</p> Signup and view all the answers

    Which of the following is an example of breaking the chain of transmission by blocking the portal of exit?

    <p>Wearing a mask when you have a cold (C)</p> Signup and view all the answers

    How does the body's mechanical defense barrier work?

    <p>It physically blocks foreign material from entering the body. (D)</p> Signup and view all the answers

    Why does the body's acidic environment make it difficult for microorganisms to survive?

    <p>The acidic environment inhibits the growth of microorganisms. (B)</p> Signup and view all the answers

    What distinguishes RNA viruses from DNA viruses?

    <p>RNA viruses can create both messenger RNA and DNA. (C)</p> Signup and view all the answers

    Which of the following is a characteristic of fungal infections?

    <p>Fungi can overgrow when the immune system is compromised. (A)</p> Signup and view all the answers

    How do parasites generally sustain themselves?

    <p>By depending on the host for shelter and nutrients. (D)</p> Signup and view all the answers

    Which statement about mycotic infections is true?

    <p>Candida is a common cause of fungal overgrowth. (D)</p> Signup and view all the answers

    What is a primary method of identifying parasitic infections?

    <p>Visualizing the adult parasite or its eggs. (C)</p> Signup and view all the answers

    What is a common consequence of antibiotic use regarding fungal infections?

    <p>Loss of normal flora leading to fungal overgrowth. (C)</p> Signup and view all the answers

    Which of the following symptoms is associated with protozoan parasitic infections?

    <p>Abdominal pain and diarrhea. (B)</p> Signup and view all the answers

    What role do host cell enzymes play in DNA virus replication?

    <p>They replicate the viral DNA. (B)</p> Signup and view all the answers

    What is a characteristic of Gram-positive bacteria when observed under a microscope?

    <p>They appear dark purple. (D)</p> Signup and view all the answers

    What are spirochetes classified as?

    <p>Cork-screw shaped bacteria. (D)</p> Signup and view all the answers

    Which group of bacteria is known to be nonmotile and may form clusters?

    <p>Cocci. (C)</p> Signup and view all the answers

    How do bacteria typically spread once they penetrate the body's initial defenses?

    <p>Via blood, interstitial fluids, and lymph. (B)</p> Signup and view all the answers

    What is a major consequence of bacteria overwhelming the lymph nodes?

    <p>Development of bacteremia or sepsis. (D)</p> Signup and view all the answers

    What type of genetic material do viruses contain?

    <p>DNA or RNA encapsulated within a virus particle. (A)</p> Signup and view all the answers

    In which method can a virus enter a host cell for replication?

    <p>By phagocytosis or surface adhesion. (B)</p> Signup and view all the answers

    What happens to the host cell when a virus replicates within it?

    <p>The cell's maintenance mechanisms are continuously broken down. (A)</p> Signup and view all the answers

    Which of the following is NOT a factor that influences the prevalence and transmission of infectious diseases?

    <p>Availability of antibiotics (D)</p> Signup and view all the answers

    What is the concept of "herd immunity"?

    <p>Achieving a high enough vaccination rate in a population to prevent widespread disease outbreaks. (D)</p> Signup and view all the answers

    Which of the following is a direct consequence of fecal contamination of food?

    <p>Increased risk of parasitic infections (C)</p> Signup and view all the answers

    What is the primary role of "normal parasitic flora" in the human body?

    <p>Protecting the host against other pathogens. (D)</p> Signup and view all the answers

    Which of the following is an example of a symbiotic relationship between a host and its normal flora?

    <p>Bacteria in the gut producing vitamin K for the host. (D)</p> Signup and view all the answers

    Which of the following is NOT a reason why some infections have a seasonal pattern?

    <p>Availability of specific antibiotics for different seasons. (C)</p> Signup and view all the answers

    Which of the following is a key factor in the development of "herd immunity"?

    <p>A high vaccination rate within the population. (A)</p> Signup and view all the answers

    Which of the following best describes the relationship between “colonization” and “resident flora”?

    <p>Resident flora are specific types of microorganisms that contribute to colonization, which is the harmless inhabitation of the skin or mucous membranes. (A)</p> Signup and view all the answers

    What is the primary function of the bacterial slime layer?

    <p>Preventing recognition and phagocytosis (A)</p> Signup and view all the answers

    Which of the following is a characteristic of endospores?

    <p>They are dormant cells that can regenerate when conditions become favorable. (C)</p> Signup and view all the answers

    Why is it important to complete the full course of antibiotics prescribed by a doctor?

    <p>To prevent the spread of antibiotic-resistant bacteria. (C), To ensure that all bacteria are killed, preventing development of resistance. (D)</p> Signup and view all the answers

    Antimicrobial resistance is a growing concern because:

    <p>Bacteria can mutate in response to environmental changes, including antibiotics. (B)</p> Signup and view all the answers

    Which of the following is NOT a characteristic of exotoxins?

    <p>They are associated with Gram-negative bacteria. (A)</p> Signup and view all the answers

    Which of the following best describes the impact of tetanospasmin, the exotoxin produced by C.Tetani?

    <p>It leads to uncontrolled muscle spasms. (D)</p> Signup and view all the answers

    What is the primary trigger for the release of endotoxins from bacteria?

    <p>The death and breakdown of the bacteria. (A)</p> Signup and view all the answers

    Which of the following features would be most beneficial for a bacterium to survive in a harsh environment?

    <p>The ability to form endospores. (B)</p> Signup and view all the answers

    Study Notes

    Infection

    • Infections are caused by microorganisms called pathogens that enter the body.
    • Major types of pathogens include bacteria, viruses, fungi, and parasites.
    • Transmission of infection involves a chain of events for one human to infect another.
    • See Figure 8-1

    Transmission of Infection

    • Pathogens must live and reproduce in a reservoir (e.g., human for influenza, animal for rabies).
    • Pathogens need a portal of exit and a mode of transmission from the reservoir to a susceptible victim (e.g., semen in sexual contact).

    Direct vs. Indirect Transmission

    • Direct transmission involves contact between the reservoir and the new host.
    • Indirect transmission involves the reservoir depositing the pathogen on an inanimate object (fomite) that transmits it to a new host.
    • Examples of direct contact include physical contact, fecal contamination, and airborne droplets.

    Transmission of Infection (Continued)

    • Pathogens gain entry to a victim through portals such as the nasal cavity or skin puncture.
    • If the host is susceptible, the pathogen multiplies and overwhelms the host's immune system, leading to infection.
    • The cycle repeats as the infected host becomes a reservoir.
    • Factors affecting susceptibility include age, gender, genetics, immune system state, and stress level.

    Colonization

    • Colonization occurs when there's balance between a host and microorganism, controlling the location and total number of the pathogen in the host.
    • Pathogens may not necessarily cause infectious diseases but can be transmitted to other hosts.

    Control of Disease

    • Breaking the transmission chain involves identifying vulnerabilities in the chain.
    • Examples include rabies vaccinations to eliminate a reservoir and having patients with TB wear masks to block portal of exit.

    The Host

    • The human body has mechanical and biochemical barriers.
    • Epithelial barriers prevent foreign material entry.
    • The skin provides multiple protective layers, especially when dry (microorganisms prefer moist).
    • Constant shedding of the epidermis and mucous membranes help with removal.
    • High fat content of the skin inhibits bacterial and fungal growth.

    Mucous Membrane Linings

    • Mucous membrane linings separate the internal body, which is sterile, from the external environment.
    • Respiratory tracts have mucous to trap and remove microorganisms.
    • Chemical barriers such as skin, urine, and vaginal acidity inhibit bacterial growth.
    • Stomach acid (pH 1-2) is inhospitable for many microorganisms.

    Antimicrobial Chemicals

    • Saliva, mucous, tears, and sweat contain antimicrobial chemicals, such as lysozyme, that destroy bacterial cell walls.

    Lactoferrin & Sebaceous Secretions

    • Lactoferrin in body fluids (saliva, tears, mucous) reduces free iron, essential for bacterial replication.
    • Sebaceous gland secretions act as antifungals.

    Immunoglobulins

    • Immunoglobulins (IgA and IgG) prevent entry of bacteria and viruses through mucous membranes.

    Infection (Continued)

    • If body barriers are removed or compromised, infection is likely.
    • Individuals with missing skin (burn victims) are at high infection risk.
    • Urine flushes bacteria in healthy urinary tracts; catheters disrupt this.

    Immunization

    • Immunization is a cost-effective method to reduce susceptibility to pathogens.
    • Immunization goals include giving immunity to the host by exposing them to altered (dead or weakened) pathogens.
    • Immunization aims to decrease the number of susceptible hosts to limit transmission.

    Microbial Adherence

    • Microbial adherence is the microorganism's capacity to attach to and enter the host.
    • Pathogens directly penetrate or adhere to hosts' tissue surfaces.
    • Adhesion molecules on pathogen surfaces aid this.

    Slime Layer

    • Microbial development of a slime layer (typically mucopolysaccharide) aids adherence.
    • Glycocalyx (slime layer) acts as an adhesive, sticking bacteria to host surfaces.
    • Streptococcus mutans produces a slime layer for tooth enamel adherence, forming plaque.

    Virulence

    • Virulence is the ability of a microorganism to evade host defenses and cause disease.
    • Higher virulence means a greater likelihood of causing harm to the host.
    • Virulence and invasiveness factors help pathogens penetrate natural barriers and resist antimicrobial therapy and phagocytosis.

    Bacterial Enzymes

    • Bacterial enzymes (fibrinolysin, coagulase, hyaluronidase) aid in pathogen spread or invasion of tissues.
    • These dissolve blood, collagen, or connective tissues.
    • For example, fibrinolysin produced by streptococci dissolves coagulated plasma to spread microbes into host tissues.

    Hyaluronidase

    • Hyaluronidase, secreted by staphylococci, clostridia, and streptococci, helps pathogens spread by dissolving hyaluronic acid, a connective tissue component.

    Encapsulation & Endospores

    • Encapsulation prevents antibody recognition and phagocytosis.
    • The bacterial slime layer prevents phagocytosis.
    • Some microorganisms make endospores to withstand harsh environments (e.g., lack of moisture, heat).

    Antimicrobial Resistance

    • Microorganisms can mutate to adapt to changes in host environments and develop antimicrobial resistance.
    • Insufficient antibiotic courses contribute to the evolution of antibiotic-resistant strains.

    Viruses

    • Viruses are small infective agents (20-300nm) composed of DNA/RNA with protein capsids.
    • They replicate inside host cells, needing their energy.
    • Some viruses form envelopes with host membrane and viral proteins.
    • Viral infections are, in many cases, self-limiting, & few antiviral agents exist.

    Viral Infection

    • Viruses invade host cells to replicate.
    • Viral adherence to cell membranes initiates entry and often causes phagocytosis.
    • Inside, the virus' genetic material is exposed for replication within the host's cell
    • Some viruses inject genetic material into host cell without engulfment.

    Two Categories of Viruses

    • DNA viruses (e.g., herpes simplex) first produce messenger RNA in the host cell nucleus.
    • Host cell enzymes then replicate the viral DNA within the host cell.
    • RNA viruses (e.g., influenza) replicate alongside host cell DNA.

    Fungi

    • Fungi are eukaryotic protists that can reproduce through division or genetic combination.
    • Fungal infections are called mycotic infections or mycoses.
    • Fungi colonize areas by adherence and proliferation.
    • Fungi like Candida live naturally in the body as normal flora; overgrowth can occur when the immune system is compromised.

    Patients on Antibiotics and Fungi

    • Patients on antibiotics lose some normal flora, making them more susceptible to fungal overgrowth.
    • Fungal infections are frequent in individuals with weakened immune or those with high nutrient environments.
    • Topical fungal drugs can treat superficial infections.

    Parasites

    • Parasites (protozoa, roundworms, flatworms, arthropods) live in or on humans, relying on the host for survival.
    • Symptoms depend on the parasite's location; for example, protozoan infections in the gut can cause cramping, abdominal pain, and diarrhea.
    • Infections can be identified by microscopic examination of blood, feces, or tissue samples.

    Types of Pathogens (Bacteria)

    • Bacteria are single-celled organisms without internal organelles.
    • Bacteria are grouped by cell wall shape and movement mechanisms: gliding, spirochetes, mycoplasmas, and rigid bacteria.

    Free-Living Bacteria

    • Rigid bacteria, including free-living bacteria, come in three basic shapes: cocci (round), bacilli (rod-shaped), and spiral.
    • Free-living/rigid bacteria may be grouped in clusters, chains, pairs, or tetrads.

    Gram Stain

    • Gram stain reaction depends on the ability of bacteria to retain a basic dye after iodine fixation.
    • Gram-positive organisms stain dark purple, gram-negatives appear pink.

    Studying That Suits You

    Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

    Quiz Team

    Related Documents

    PPY 400: Unit 3 Infection - Past Slides PDF

    Description

    Test your knowledge on pathogens, their transmission, and the body's defense mechanisms in this comprehensive quiz. Explore key concepts such as immunity, barriers to infection, and factors affecting susceptibility. Ideal for students studying microbiology or health sciences.

    More Like This

    Use Quizgecko on...
    Browser
    Open
    Browser
    Browser