Test 2 – Microbiology Test Answers – Flashcards
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| Which of the following archaea are opportunistic pathogens of humans? |
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| no archaea are pathogens (at least none that of which we know) |
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| Which of the following act as barrier defenses against the entry of pathogens into the body? |
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| Skin, mucus, ciliated epithelial cells, and stomach acid are all examples of barrier defenses that act to prevent the entry of pathogens into the body. |
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| Cholera toxin is an example of a cytotonic enterotoxin. What is a cytotonic enterotoxin? |
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| a toxin that acts in the gastrointestinal (GI) tract , a toxin that alters host cells without killing them (entero in GI tract, -tonic alters activity vs -lytic which kills) |
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| Certain organisms, for example Salmonella Typhi, are able to establish a state of chronic carriage in some individuals. What does chronic carriage mean? |
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| the organism colonizes or establishes inapparent infection in those individuals |
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| Which of the following is/are clinical signs of disease? |
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| Fever (stuff you can measure) |
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| The Gram-positive bacterium, Clostridium difficile, an obligate anaerobe, can give rise to endogenous infections that result in antibiotic-associated gastrointestinal disease. Which of the following statements about C. difficile is/are correct? |
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| -presence will always cause disease -grow best at low oxygen levels -it's endogenous: meaning it is normally in our intestines but doesn't cause disease until normal bacteria is wiped out by antibiotics Can colonize healthy people |
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| What happens when a pathogen infects a dead-end host? |
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| The pathogen cannot be transmitted to a new host |
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| Diphtheria toxin is an example of a cytolytic toxin. What is a cytolytic toxin? |
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| a toxin that causes cell death |
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| What class of microbial pathogens causes most endogenous infections of humans? |
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| Bacteria |
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| Which of the following is/are characteristics of organisms that establish exogenous infections in humans? |
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| They don't colonize humans before infecting them |
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| Which of the following are characteristics of a facultative intracellular pathogen? |
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| it can grow inside host cells and also outside host cells |
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| Excessive cytokine production causes which of the following immunopathologies? |
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| Toxic shcok syndrome, Delayed Type hypersensitivity (DTH) reactions, chronic inflammation. (all of the above) |
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| The Gram-negative bacterium, Campylobacter jejuni is generally considered to have a low infective dose in humans. What does it mean to have a low infective dose? |
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| only a few organisms are necessary to cause disease |
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| Which of the following mechanisms for local invasion of tissues potentially could be employed by an obligate extracellular pathogen? |
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| cytolytic exotoxins are produced by the invading pathogen, hyaluronidase is produced by the invading pathogen |
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| Which of the following types of clinical specimens would not normally contain microorganisms (specimens come from normally sterile sites)? |
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| blood, cerebral spinal fluid |
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| The Gram-positive, spore-forming bacterium Bacillus anthracis is an obligate pathogen of humans. What is an obligate pathogen? |
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| an organism that always causes disease when in a host |
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| In the context of medical microbiology, the term ?Parasite? refers specifically to which of the following? |
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| any eukaryotic pathogen that is not a fungus |
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| Which of the following may be consequences of a failure by the immune system to resolve an infection? |
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| death of host, persistent infection of the host |
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| Which of the following are virulence factors commonly found among protozoan parasites? |
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| adhesins, secreted phos |
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| Which of the following are possible outcomes of viral interaction with a cell? |
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| infection without cell death, failed infection, latent infection, cell death (all of the above) |
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| Which of the following are routes by which pathogens potentially can disseminate within the body? |
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| systemic spread of microbe after local invasion at or near PoE, loaclized infection or systemic disease |
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| Which of the following factors determine whether an opportunistic pathogen will cause disease? |
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| whether the host is immunodeficient, virulence factors, inoculum load of pathogen is high |
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| Among viruses that commonly cause human disease, which of the following virus?host interactions result in active replication and production of new virus particles? |
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| infection without cell death |
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| Which of the following are cell?mediated effectors of the adaptive immune system? |
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| TH1 T cell, cytotoxic T-lymphocyte |
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| Which of the following statements is/are true of the adaptive immune system in humans? |
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| adapts to microbes/pathogens you're exposed to during life, specifically recognizes molecules, requires times initiated by innate immune system |
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| Which of the following are beneficial effects of local, short?term inflammation? |
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| immune system effector molecules and cells are delivered to sites of infection increases drainage of tissue fluid into lymph generates physical barrier to spread of infection repair of injured tissue promoted |
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| Which of the following are effector functions of complement small fragments? |
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| local pro-inflammatory activity, chemoattractant for neutrophils |
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| Which of the following myeloid cell types are granulocytes? |
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| neutrophils, basophilsm eosinophils |
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| Which of the following strategies is/are used by Coxiella burnetii, the causative agent of Q fever, to prevent it from being killed after uptake into host cells by phagocytosis? |
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| resistant to environmental changes by phagolysosomes, low infectious dose, uses type IV secretion system |
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| Which of the following strategies is/are used by Mycobacterium tuberculosis, the causative agent of tuberculosis, to prevent it from being killed after uptake into host cells by phagocytosis? |
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| prevents formation of phagolysosome |
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| Which of the following strategies is/are used by Rickettsia rickettsii, the causative agent of Rocky Mountain spotted fever, to prevent it from being killed after uptake into host cells by phagocytosis? |
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| Bacteria rupture the phagosome membrane and escape into the cytoplasm of the host cell. |
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| Which of the following humoral and/or cellular effectors of the innate immune system contribute most to the control of infections caused by extracellular bacteria? |
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| complement |
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| Which of the following humoral and/or cellular effectors of the innate immune system contribute most to the control of infections caused by viruses? |
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| none (extracellular) |
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| Which of the following are humoral effectors of the innate immune system? |
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| complement |
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| Which of the following statements is/are true of the innate immune system in humans? |
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| Preformed components, early induced, has physical barriers, checkpoints, recognizes limited repertoire of pathogen-specific molecules |
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| Which of the following cell types are leukocytes? |
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| neutrophils, WBC |
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| Which of the following events occur during a local inflammatory response? |
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| synthesis of acute phase proteins, influx of phagocytic cells to site of infection |
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| Which of the following cell types of the lymphoid lineage are phagocytic? |
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| none |
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| Which of the following are effector functions of macrophages? |
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| phagocytosis and digestion of cellular pathogens and debris release pro-inflammatory cytokines release chemokines to attract neutrophils, macrophages, monocytes, lymphocytes activiate NK cells |
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| Macrophages are a differentiated form of which of the following types of cells? |
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| monocyte, myeloid lineage |
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| Which of the following molecules can act as opsonins? |
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| complement large fragments, specific antibodies, acute phase proteins, |
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| Which of the following behaviors may be induced in innate immune system cells upon detection of pathogen?specific molecules or structures? |
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| influx of phagocytic cells to site of infection local inflammation synthesis of acute phase proteins |
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| Which of the following types of bactericidal molecules are made from scratch in the phagolysosome of macrophages? |
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| hydrogen peroxide, superoxide anion, nitric oxide |
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| ?/??interferons have which of the following functions? |
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| antiviral activity, suppress infection |
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| Tumor necrosis factor ? has which of the following functions? |
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| causes cellular and physiological changes for inflammation, release pro-inflammatory cytokine, activates endothelial cells and causes increased vasuclar permeability |
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| Which of the following signs and symptoms of localized inflammation are caused by vasodilation? |
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| heat and redness |
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| Which of the following do the mechanisms of cell killing used by phagocytes and cytotoxic Tlymphocytes have in common? |
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| cell-mediated immunity |
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| Which of the following kinds of antigens can be recognized by B-cell receptors? |
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| Proteins Peptides (small protein fragments) Polysaccharides (carbs) Haptens (small molecules of any kind) |
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| Staphylococcus aureus is an encapsulated, extracellular bacterial pathogen that can cause a variety of diseases. Which of the following humoral and/or cellular effectors of the immune system would be most important for clearing S. aureus infections? |
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| Antibody and Neutrophils |
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| Following vaccination with MMR, which of these humoral and/or cellular effectors of the immune system would be most important for clearing the virus infections? |
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| CTLS and Neutralizing Antibodies |
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| Which of the following cell types can present antigens to naive CD8+ T-cells? |
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| Plasmacytoid dendritic cells |
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| L. pneumophila is a bacterium that is taken up by macrophages by phagocytosis. L. pneumophila blocks phagolysosome fusion and grows in the phagosome.Which of the following humoral and/or cellular effectors of the immune system would be most important for clearing L. pneumophila infections? |
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| TH1 T cells and activated macrophages |
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| Which of the following vaccines, identified by their abbreviations, are polysaccharide-conjugates? |
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| Hib, MCV, PCV |
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| Why are conjugate vaccines needed in infants to confer immunity to encapsulated bacteria? |
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| T-independent antibody responses are not fully developed in infants. Bacterial capsular polysaccharide antigens require an unusual form of T cell help to genrate a anitbody response. This form of T cell help is not present in infants until age 2 |
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| Human immunodeficiency virus (HIV) infects CD4+ T-cells and ultimately kills them. Untreated HIV infection results in the acquired immune deficiency syndrome (AIDS). Which of the following immune system defects in AIDS patients is/are directly caused by the loss of CD4+ Tcells? |
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| Activation of macrophages by TH1 T cells phagocytosis of extracellular bacteria by neutrophils extravasation of monocytes killing of infected host cells by cytotoxic t lymphocytes |
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| Which of the following statements is/are true of herd immunity? |
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| It can protect a population against pathogens when not every individual is immune. It can apply to populations of any kind of organisms Is not applicable to pathogens that cannot be transmitted horizontally The specific fraction of the population must be immune for herd immunity to operate varies depending on the shedding and transmission characteristic of the pathogen. |
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| Human papillomavirus type 18 (HPV-18) is sexually transmitted and can establish persistent infections of mucosal epithelia. Following vaccination, which of the following humoral and/or cellular effectors of the immune system would be most important for protecting against HPV-18 infection? |
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| neutralizing antibodies |
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| Which of the following vaccines, identified by their abbreviations, are polysaccharideconjugates? |
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| MCV4 and Hib |
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| Which of the following cell types contribute to the maintenance of serum antibody levels after resolution of an infection? |
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| Long term producer B Cells, Plasma Cells, T Cells |
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| Which of the following applications of epidemiology typically would be used to monitor an ongoing immunization program? |
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| Data collection Data analysis Determine frequency with which disease is observed vs expected in each sement of population Data from medical records or surveys |
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| Which of the following statements is/are true of immunological memory? |
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| It is conferred in part by pools of antigen specific memory T cells Memory B cells do not secrete antibody Activation of naive b cells are suppressed during second exposure to antigen |
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| Why does the number of microbes present in the body keep increasing during the early phase of a typical adaptive immune response? |
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| The innate immune system has failed to control the infection Time is required for clonal expansion of lymphocytes to take place Humoral and cell mediated effectors of the adaptive system have not yet been produced in sufficient numbers. |
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| Which of the following are features of the immune response to a secondary antigenic challenge? |
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| Memory B cells reactivated IgG is produced before IgM Antigen specific memory T-cells will be reactivated Secondary response occurs faster than primary |
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| Against which of the following vaccine-preventable diseases is/are the U.S. general public immunized routinely? |
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| Hib PCV HPV IPV DtaP Hep A Hep B Rv Influenza MCV4 MMR Varicella |
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| Which of the following vaccines, identified by their abbreviations, contain infectious (live) viruses? |
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| Varicella Zoster |
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| Which of the following diseases is the Tdap vaccine intended to prevent? |
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| Diphtheria, tetanus, pertussis |
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| Which of the following immune responses is/are defective in patients who have AIDS? |
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| no TH1 or TH2 |
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| Which of the following humoral and/or cellular effectors of the immune system would be most important for clearing L. pneumophila infections? |
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| TH1, CTL, NK |
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| Which of the following is/are characteristics of an inapparent infection? |
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| Fever, Inflammation, flu like symptoms |
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| Which of the following are possible outcomes of infection with hepatitis B virus? |
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| Cirrhosis of the liver and hepatocellular carcinoma associated with chronic infection by hepatitis B virus. ( develop long-term sequelae/ persistent infection) |
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| Which of the following is/are characteristic of organisms that establish endogenous infections in humans? |
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| a. Endogenous infections are caused by microbes that normally colonize the host. b. Amoung the four classes of pathogens, only bacteria and fungi normally colonize humans, and bacteria are by far the most common to cause endogenous infections. |
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| The Gram-negative bacterium, Vibrio cholerae generally is considered to have a high infective dose in humans. What does it mean to have a high infective dose? |
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| A lot of bacteria have to be ingested in order to cause disease |
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| Which of the following factors contribute to pathogenesis (disease causation) for all types of microbial pathogens (bacteria, viruses, fungi, and parasites)? |
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| virulence factors inflammation cytotoxins antigenic variation interference (e.g reduces expression of MHC 1 on infected viruses) stealth (hiding from immune system ) misdirection of immune responses |
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| Which of the following cell types is/are involved only in antigen-spcific immune responses? |
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| a. T-lymphocytes and B-lymphocytes |
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| People with liver damages have reduced capacity to control infection by a number of bacteria and fungi. Which of the following immune systemcomponets would you expect to be affected directly by liver damage? |
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| a. Macrophages activated in the liver and spleen screte TNF-a into the bloodstreem; this induces a local protective effect. Macrophages release TNF-a. Systemic infection with gram-neg bacteria: sepsis. |
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| After encontering a pathogen in perifperal tissues, plasmacytoid dendritic cells do which of the following? |
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| a. They are lymphoid lineage Although not part of the phagocytic effector response of the immune system, plasmacytoid dendritic cells, in common with myeloid dendritic cells, use phagocytosis to sample antigens from pathogens. Peptides generated inside the vacuolar compartment are displayed by MHC II molecules on the surface of the dendritic cell. These peptide antigens are then presented to CD4 + T-cells to initiate adaptive immune responses. None of the other lymphoid cell types is phagocytic. |
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| Which of the following cell types can activate macrophages? |
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| T-lymphocytes (TH1 Cell) |
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| What two types of signaling molecules are secreted by macrophages when they detect bacteria? |
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| a. cytokines and chemokines. |
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| What is the purpose of clonal deletion during lymphocyte development? |
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| a. developing lymphocytes that are poteintally self-reactive are removed before they can mature. |
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| What is the purpose of clonal expansion during an adaptive immune response? |
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| a. in Activated immunity the proliferatoino and differentiation of activated specific lymphoyes to form a clone of effector cells ; effector cells eliminate antigens. |
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| If a person is exposed to rabies virus via a bite wond, what class (es) of antibody directed against the virus would be most likely to prevent systematic spread of the infection? |
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| a. IgG and IgA |
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| Vibrio Cholerae O1 is an extracellular pathogen that causes disease without invading tissues. What class (es) of antibody directed against V. cholerae O1, or its exotoxin, would be able to protect against infection by the bacterium? |
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| a. IgG, IgA |
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| Which of the following are factors that might predispose an affected person to Chromobacterium violaceum infection? |
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| host immune system weakened microbe gains access to normally sterile sites large inoculum size microbe has virulence factors |
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| Which of the following strategies may be used by intracellular pathogens to avoid being killed following phagocytosis into macrophages? |
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| polysaccharide capsule enzymes capable of lysing phagocytic cells blocking phagolysosome fusion |
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| Which of the following are effector functions of complement large fragments? |
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| Get cross linked onto target cell membrane (limits diffusion), prevents collateral damage, opsonize bacteria (makes them susceptible to bacteria). |
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| Which of the following are characteristics of a pathogen-associated molecular pattern? |
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| receptors of PAMPS are invariant are signatures of broad classes of pathogen are detected by binding to host cell receptors or to secreted molecules. are souble (diffusible) molescules like fMLF and LPS are part of pathogen surfaces repeating mannose-fucose units in bacterial cell walls. |
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| Which of the following types of leukocytes may undergo extravasation at a site of local inflammation? |
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| a. neutrophils and macrophages are the principal inflammatory cells. |
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| Which of the following important molecules of the innate immune system are involved in attracting leukocytes to sites of infections? |
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| a. Dendrtic cells |
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| Which of the following are among the microbial cell killing mechanisms used by phagocytes? |
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| engulfment of microbe in a phagosome phagosome acidifies and fuses with lysosome acidification formation of toxic oxygen formation of toxic nitrogen oxides antimicrobial peptides enzymes competitors |
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| Which of the following cell types can present antigens to CD8+ T-Cells? |
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| a. MHC class I, dendritic cells |
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| Mycobacterium tuberculosis is an intracellular pathogen that infects macrophages. Which of the following humoral and/or cellular effectors of the immune system would be most important for combating infection by M. tuberculosis ? |
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| Natural Killer Cells |
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| Clostridium tetani is an extracellular pathogen that can cause systemic disease, even though it does not invade tissues. What class(es) of antibody directed against C. tetani , or its exotoxin, would be important for preventing tetanus? |
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| IgA |
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| Which of the following cell types can activate B cells to produce antibody? |
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| a. Professional antigen presenting cell. pg. 343/Native B Cells |
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| Unlike Vibrio cholerae, the related extracellular bacterium Vibrio vulnificus can cause invasive disease (septicemia). What isotype(s) of antibody generated in response to infection would contribute to the control of V. vulnificus invasive disease, but not to the control of V. cholerae infection? |
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| IgM and IgG |
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| Where in the body would activated dendritic cells most commonly be found? |
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| peripheral tissue |
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| After encountering a pathogen in peripheral tissues, myeloid dendritic cells do which of the following? |
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| Bind and phagocytose any pathogen molecules (antigens), migrate to afferent lymphatics, and then go to the nearest lymph nodes |
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| In which of the following places in the body would macrophages be found? |
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| Peripheral Tissue |
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| In which of the following places in the body would naive lymphocytes be found? |
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| Efferent lymphatics, blood, lymph node |
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| Which of the following drug-resistance mechanisms is/are found only in bacteria? |
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| Drug Inactivation |
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| In which of the following classes of pathogen does antimicrobial drug resistance occur by enzymatic inactivation of the drug? |
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| Bacteria |
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| In which of the following classes of pathogen does antimicrobial drug resistance occur through mutations in target enzymes that prevent drug binding? |
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| Fungi, Parasites, Bacteria, and Viruses (all of them) |
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| Which are examples of immediate actions that might be taken by public health authorities in response to case of a reportable disease? |
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| Isolation, Restriction, Emerging Pathogen Surveillance, PEP of Case Contacts Needed, and Contact Tracing |
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| Which of the following diseases should be reported immediately to the local health department if they are suspected by a physician in North Carolina? |
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| Anthrax, Botulism, Plague, Smallpox, Tulgaremia, Novel Influenza, and Hemorrhagic Fever Virus |
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| A pos. PPD skin test for tuberculosis involves which of the following humoral and/or cellular effectors of the adaptive immune system? |
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| Cytokines |
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| For which of the following types of infectious disease would supportive care alone be an appropriate treatment? |
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| For diseases where treatment doesn't improve outcome or noncurative diseases such as Ebola/Hemorrhagic Fever and HUS |
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| What type of infections is combination therapy with antimicrobial agents intended to treat? |
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| Persistent Infection |
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| Which of the following potentially could be a curative treatment for an infectious disease? |
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| Antimicrobial agents or Surgical Treatment |
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| Which of the following types of test results might help a clinician to refine a differential diagnosis? |
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| Blood work, acid fast test, gram stains, culture, serology (ELISA), PCR, PPD, or Chest X-Rays |
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| In which of the following places in the body would naive lymphocytes encounter their antigen for the first time? |
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| Lymph nodes |
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| Which of the following types of intracellular pathogens would be expected to enter cells by phagocytosis? |
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| Bacteria, fungi, or parasites |
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| Which of the following types of intracellular pathogens would be expected to enter cells by endocytosis? |
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| viruses |
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| Which of the following are effector functions of terminal complement components? |
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| Signal for help, pro-inflammatory signal, and enhances phagocytosis |
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| Which of the following are effector functions of neutrophils? |
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| Act as phagocytes |
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| Which of the following are effector functions of natural killer cells? |
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| kill any abnormal host cells |
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| Which of the following are similarities between the cell killing mechanism utilized by the complement system and that of natural killer cells? |
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| Both create pores in target cell's cell membrane |
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| In which of the following places in the body would monocytes be found? |
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| Peripheral tissues |
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| Which of the following are potential targets of antimicrobial drugs? |
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| growth and actual microbe |
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| Which of the following mechanisms can lead to drug resistances in viruses? |
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| target alterations |
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| Which of the following are components of cough etiquette (respiratory hygiene)? |
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| Cover mouth and nose when you sneeze cough into tissue, sleeve, but not hand discard used tissues into waste container washing hands with soap and running water practice hand hygiene afterwards |
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| Which of the following pathogens are transmitted by the airborne route? |
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| ? Measles virus ? Tuberculosis ? Varicella Zoster |
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| Against which of the following diseases could herd immunity help to protect a human population? |
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| Whopping cough, pertussis |
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| Which of the following are considered to be vertical routes of pathogen transmission? |
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| Spread of infection from mothers to newborns This can occur across the placenta during pregnancy (placental fetal) during process of giving birth (maternal parturition) after birth when pathogen is passed from mother to newborn (maternal neonatal) |
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| Which of the following is/are characteristics of most pathogens that are maintained in humans? |
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| Infect only humans, |
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| In public health, which of the following is/are control measures that would be implemented only in response to an outbreak of disease? |
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| Recall of contaminated food Isolation orders and quarantine orders Post exposure prophylaxis |
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| Which of the following may be vectors for human pathogens? |
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| Ticks, Fleas, Mosquitoes |
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| Which of the following statements is/are true of zoonotic infections? |
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| They are always caused by pathogens that have animal reservoirs Infections that are transmitted to humans from a vertbrate, non-human reservoir can occur with direct or indirect contact unable to be transmitted from human to another human |
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| Use of disinfectant would be appropriate for which of the following? |
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| Reducing microbial contamination of surfaces |
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| Which of the following types of pathogens are most likely to be transmitted vertically by the maternal-parturition route? |
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| Pathogens transmitted horizontally by urogenital sexual route |
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| Which of the following constitute active surveillance for disease outbreaks? |
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| Real time monitoring by public health agencies of hospital admission data and sentinel sites |
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| Which of the following characteristics would enable a pathogen to be transmitted efficiently to naive hosts? |
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| It becomes airborne in respiratory droplet nuclei |
