ETSU Introduction to Microbiology Exam Three – Flashcards
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Transformation is a mode of genetic recombination in which a plasmid is transferred from a donor cell to a recipient cell via a direct connection
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False
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DNA is the blueprint that indicates which kinds of proteins to make and how to make them.
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True
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The ______ is the sum total of genetic material in a cell
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Genome
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Please select all of the characteristics of DNA to test your understanding of its chemical structure.
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Deoxyribose sugar Phosphate group Nitrogenous bases
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When one bacterium donates DNA to another bacterium, a type of genetic recombination known as _________ has occurred.
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horizontal gene transfer
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Genetic ______ and the variations they produce result in population changes and thus, evolution.
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Mutations
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Complete removal or destruction of all microbial forms _____?
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Sterilization
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Destruction or removal of vegetative pathogens (but not endospores) from inanimate surfaces
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Disinfection
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Destruction of vegetative pathogens on skin and tissue
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Antisepsis
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Techniques that prevent the entry of microorganisms into sterile tissue
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Asepsis
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Cleansing technique that removes microorganisms and debris into inanimate surfaces
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Sanitization
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Select all the factors that influence the effectiveness of antimicrobial chemicals
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Numbers and kinds of microbes present, Concentration of the chemical, Presence of organic matter, Nature of the material being treated, Temperature
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Order the following microbes or microbial forms in terms of their resistance to control methods, beginning with those who are most resistant. Mycobacterium tuberculosis, Enveloped viruses, Gram-positive bacteria, Bacterial endospores, Prions
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Prions, Bacterial endospores, Mycobacterium tuberculosis, Gram-negative bacteria, Enveloped viruses
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A chemical labeled as _______ will inhibit bacterial growth but will not kill them.
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Bacteriostatic
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Select the choices which indicate the effects of heat on microbes
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Denatures protein, oxidizes the cellular structures
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Select items that can be sterilized using filtration
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Liquid culture media, Drugs, Air, Vaccines
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Please choose the answer that best completes the blanks of this sentence in the correct order. ______ radiation causes broad scale damage to DNA whereas UV light specifically causes formation of _______ dimer formation in DNA.
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Ionizing, pyrimidine
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Please choose the statement that best defines microbial death
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The microorganisms are permanently unable to reproduce
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Please select those characteristics of a chemical control agent that make it a desirable agent.
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Water or alcohol soluble and stable, Cidal to a wide range of microbes, but nontoxic to humans and animal tissue, Rapidly effective in low concentrations, inexpensive
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Please select the statement that describes the antimicrobial activity of alcohols
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Disrupt membrane lipids and denature proteins
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Please choose the statement that identifies the major disadvantage of both cold and desiccation in terms of microbial control.
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These methods are bacteriostatic rather than bactericidal
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Please choose the microbial control method that neither inhibits nor kills microbes, but instead physically removes them from liquids or air.
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Filtration
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Please select the factors below that influence the effectiveness of an antimicrobial agent
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Temperature, Number of microorganisms, Presence of organic matter, Concentration of dosage of the agent
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Please select the four primary targets of antimicrobial control agents
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Cell wall, Cell membrane, Protein and nucleic acid synthesis, Protein structure and function
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A(n) _______ would be used to destroy bacteria on a countertop whereas a(n) _______ would be used on skin prior to making an incision.
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disinfectant; antiseptic
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Please choose the answer that correctly fills in the blanks of this sentence in order. _______radiation has good penetrating power and can be used for cold sterilization, whereas _______ radiation doesn't penetrate well and is more often used for disinfection purposes.
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ionizing; nonionizing
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An antimicrobial agent's adverse effect on cells is known as its _______
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Mode of action
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Such antimicrobials exhibit a range of cellular targets, the ______ selective being the most effective against the widest range of microbes and the _____ selective agents exhibiting specificity in terms of cellular targets and microbial types they are effective against.
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least;most
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Potential cellular targets of various physical and chemical forms of antimicrobials include the ________, whose synthesis can be blocked by these agents or whose structure can be altered as well.
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cell wall
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Another potential target is the ________, whose surface tension can be reduced by various microbicidal agents resulting in a loss of selective permeability in the cell.
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cell membrane
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Physical and chemical agents can also interfere with _______synthesis through disruption of ribosome activity, protein function through the denaturation of a protein's native state, and finally disrupting the synthesis or structure of __________.
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protein; nucleic acids
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CASE STUDY: True or false: All cases of Hepatitis C present with symptoms of nausea, vomiting, abdominal pain, and jaundice.
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False
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CASE STUDY: The patients who contracted HCV in this case were infected due to which of the following?
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proper procedures for drawing up sedation drugs
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CASE STUDY: HCV is mainly transmitted through what means?
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Blood-to-blood contact
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CASE STUDY: True or false: All of the patients with acute HCV in this case were infected with strains of HCV that were genetically identical.
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True
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CASE STUDY: How many people are infected with hepatitis in the United States alone?
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5 million
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CASE STUDY: True or false: Researchers at Stanford University have discovered a treatment that will inhibit hepatitis virus in humans.
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False
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CASE STUDY: _____ acts like an "anti-gene" and destroys specific genetic information.
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RNA interference
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CASE STUDY: How does RNA interference work?
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Prevents the replication of the hepatitis virus
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CASE STUDY: How effective is this treatment in mice?
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85-99%
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CASE STUDY: Why were patients who contracted HCV at the endoscopy clinic also directed to be tested for HBV and HIV?
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HBV and HIV are also blood-borne infections, and the source of the infection may also have been infected.
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CASE STUDY: What factors led the CDC to suspect that the endoscopy clinic was the source of the HCV outbreak?
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All of these (In this case, none of the patients infected had any risk factors for HCV, they did not have any contact with each other, but most importantly the strains of HCV were genetically similar, leading investigators to suspect a common source.)
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CASE STUDY: Why did all 50,000 clinic patients need to be tested for HCV?
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Because they all were potentially exposed to HCV due to improper protocols at the clinic.
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CASE STUDY: Why did all 50,000 clinic patients need to be tested for HCV?
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All of these (liver failure, liver cancer, cirrhosis)
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CASE STUDY: Where does Acinetobacter baumannii typically live?
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Soil and water
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CASE STUDY: Infections caused by A. baumannii have most frequently been seen in which group of people?
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Soldiers returning from current battle fields
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CASE STUDY: A "nosocomial" infection is an infection acquired through which means?
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Admission to a hospital for other reasons
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CASE STUDY: What was the most probable source of A. baumannii in this woman's infection?
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Ventilator tube
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CASE STUDY: The strain of A. baumanni cultured late in this woman's infection was most likely a(n) ______ strain.
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XDR
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CASE STUDY: Conjugation
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Requires direct contact between two live cells, Utilizes pilus to transfer DNA
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CASE STUDY: Transformation
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Griffith Experiment, Live cell takes up DNA fragment
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CASE STUDY: Transduction
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Uses a viral vector to transfer donor DNA, Donor and recipient must be same species
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CASE STUDY: What does drug resistance mean from a genetic standpoint?
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The organism contains genes that code for the ability to withstand the drug's effects.
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CASE STUDY: Acinetobacter baumannii has the ability to acquire resistance to multiple antibiotics through:
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All of these (Since the genes for antibiotic resistance found in A. baumannii are identical to those found in other microbial species, it is likely that it acquired these genes through horizontal gene transfer mechanisms.)
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CASE STUDY: Which of the following structures could assist A. baumannii in acquiring drug resistance genes from another organism?
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Pilus
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CASE STUDY:True or false: The colistin used to treat the pneumonia patient in this case likely transformed the genetic material in the pathogen, giving it the ability to resist destruction by the drug.
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False
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CASE STUDY: Based on the information in this particular case, what would be a good general practice to prevent the emergence of drug resistant strains of bacteria in the future?
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Use antibiotics wisely and sparingly
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CASE STUDY: What was the immediate course of post-exposure prophylaxis for the nurse in this case?
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Anti-HIV drugs for possible HIV infection
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CASE STUDY: What is the purpose of post-exposure prophylaxis after a needle stick injury occurs?
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To inhibit HIV before it has the opportunity to replicate in cells
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CASE STUDY: What was the actual cause of the nurse's skin lesion at the site of the needle stick?
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TB Infection
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CASE STUDY: True or false: Penicillin is an effective form of treatment for tuberculosis.
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Fasle
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CASE STUDY: During which stage of viral replication does amantadine exert its inhibitory effect?
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Penetration and uncoating
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CASE STUDY: When AZT is present, which enzyme is inhibited?
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Viral reverse transcriptase
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CASE STUDY: Protease inhibitors ______.
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inhibit processing of long polypeptide chains
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CASE STUDY: Of all the antiviral drugs mentioned, which is actually produced by the host?
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Interferon
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CASE STUDY: Which of the drugs mentioned inhibits DNA polymerase?
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Foscarnet
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CASE STUDY: What are standard protocols for needle stick injuries?
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All of these (Standard procedures for needle stick injuries include washing with water, antiseptic treatment with betadine, and reporting the injury to a supervisor to begin post-exposure prophylaxis.)
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CASE STUDY: What drug(s) are included in post-exposure prophylaxis for HIV
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Reverse transcriptase inhibitors
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CASE STUDY: What common problem involving drug therapy was seen in this case?
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The nurse failed to complete her full course of anti-HIV drugs after the needle stick.
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CASE STUDY: Treatment of the skin abscess caused by Mycobacterium tuberculosis included _____.
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All of these drugs (All three of the antibiotics listed are used in combination to avoid and/or kill drug resistant microbes.)
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CASE STUDY: The coordinated or correlated action by the antimicrobial drugs used to treat TB is an example of a(n) ______ effect.
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synergistic
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CASE STUDY: Sensitivity testing is important for:
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For both selection and detection of resistance of a drug
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Please choose the answer that best fills in the blanks of this sentence in the correct order. An antimicrobial drug that is effective against a very diverse array of bacteria is described as ______ spectrum, whereas a drug that is very selective for a just a few different types of bacteria is described as ______ spectrum.
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broad; narrow
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Please select the five major mechanisms of antimicrobial resistance.
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Enzymatic inactivation of the antibiotic, Antibiotic efflux pumps pump the antibiotic out of the cell, Altered target site, such that the antibiotic can no longer bind to the target, Microbe uses an alternative pathway to circumvent the blocked pathway, Decreased permeability to the antibiotic
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Please select the five primary modes of actions of antimicrobial drugs
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Inhibition of cell wall synthesis, Disruption of cell membrane synthesis or structure, Inhibition of protein synthesis, Blocking of key metabolic pathways, Disruption of structure or function of nucleic acids (DNA/RNA)
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Please choose the major challenge of antiviral therapy.
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Viruses rely on the metabolic system of the host cell
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Please select the three ways in which microorganisms acquire antimicrobial resistance,
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Spontaneous mutation, Transfer of genes from other microorganisms, Entering a dormant state in the presence of antibiotics and resuming normal metabolic functions in the absence of antibiotics
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A narrow spectrum antimicrobial would be an appropriate choice to treat an abscess caused by several different microbe species, including both gram-negative and gram-positive bacteria.
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False
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Most antimicrobial drugs are derived from which two bacterial and which two fungal genera?
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Bacillus, Streptomyces, Penicillum, Cephalosporium
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Please choose the term used to describe the type of antimicrobial resistance that is of most concern today.
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Acquired
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Please select the three major mechanisms by which antimicrobial resistance genes are shared and spread among microbial populations.
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Conjugation, Transduction, Transformation
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Please select the strategies that can be used to reduce the level of antimicrobial drug resistance.
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Prescribing antibiotics ONLY for accurately diagnosed bacterial infections, Restricting use of newly developed antibiotics to those situations when the etiologic agent has been shown to be resistant to more traditional antibiotics, Limiting the use of antibiotics in animal feed
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Please select the two correct answers to test your understanding of the primary goals of antimicrobial treatment.
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To destroy the infective agent, to be nontoxic to the host and produce no side-effects
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First, Most body surfaces and outer openings of body tracts are normally colonized by a population of microorganisms referred to as the ______?
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Microflora
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Second, While most of these normal residents are harmless or beneficial, there are a small number of potential ________ that can also exist normally in the body.
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Pathogens
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Third, An issue with these harmful species can arise with the use of a _______ -spectrum antimicrobial drug.
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Broad
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Fourth, A drug with this spectrum of activity will destroy ________ regardless of their positive role in human health.
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Microbes
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Fifth, With the population of "good" microbes reduced, the resident microbes that are normally kept at small numbers can overgrow and cause _______.
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Disease
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Sixth, This complication is called a _____________.
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Superinfection
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MECHANISMS OF DRUG RESISTANCE: Drug inactivation in which -->
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Drug is changed
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MECHANISMS OF DRUG RESISTANCE: Drug binding site altered in which -->
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Drug can't bind its target
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MECHANISMS OF DRUG RESISTANCE: Drug pumps in which -->
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Drug enters but doesn't stay
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MECHANISMS OF DRUG RESISTANCE: Alternate metabolic pathway in which -->
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Drug binds correctly
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Please choose the statement that best describes superinfection.
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A secondary infection that occurs during antimicrobial therapy, caused by overgrowth of drug-resistant residents of the microbiota
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A patient who has recently undergone a total joint replacement surgery is given antibiotics prior to dental procedures?
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Prophylaxis
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A patient infected with HIV usually takes several different anti-HIV medications, including a reverse transcriptase inhibitor, one or more protease inhibitors, and an integrase inhibitor?
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Combined therapy
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Trimethoprim and sulfomethoxazole are often used together because they inhibit two successive steps in the folate biosynthetic pathway and this inhibition is greater than when either drug is used alone.
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Synergy
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The minimum number of organisms necessary to enter through the portal of entry and establish infection is the ____________.
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Infectious dose
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Presence of organisms living in or on the body, but not causing any pathology.
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Colonization
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Pathogenic microorganisms penetrate the host defenses, enter the tissues, and multiply.
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Infection
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Disruption of a tissue or organ caused by microbes or their products.
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Infectious disease
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Please choose the answer that best fills in the blanks of this sentence in the correct order. A(n) ______ pathogen causes disease in a healthy individual with a normal immune response, whereas a(n) ______ pathogen will not cause disease in a normal healthy host, but instead causes disease only when a host's defenses are compromised in some way.
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True; opportunistic
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Please identify the four most significant interactions between humans and the microbes that live in and on our bodies.
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Microbes can protect and stabilize body surfaces on which they establish themselves as normal residents. Microbes promote the development and maturation of host immune defenses. Microbes may invade and grow in normally sterile body sites. Microbes cause disease by damaging tissues and organs.
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Please select the conclusions of studies comparing the health of germ-free animals to the health of animals with a normal complement of microbiota.
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Normal microbiota are a source of some vitamins. Normal microbiota contribute to dental caries and periodontal disease. The presence of normal microbiota can prevent some pathogens from becoming well-established. Normal microbiota contribute to the development and maturation of the immune system.
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Please select the body sites that serve as portals of entry for microbes
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Vagina, nose, mouth, urethra, skin
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Please choose the best definition of virulence factors.
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Characters of microorganisms that enable it to establish infection and cause disease.
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Examples of portal of entry (step one of entry, establishment, and exit of infectious agents).
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Skin, GI tract, Respiratory trace, Urogenital tract, Endogenous biota
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Examples of adhesion (step two of entry, establishment, and exit of infectious agents).
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Fimbriae, Capsules, Surface proteins, Viral spikes, Hooks
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Examples of surviving host defenses (step three of entry, establishment, and exit of infectious agents).
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Avoiding phagocytosis, Avoiding death inside phagocyte, Evading actions of the immune system
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Examples of disease (step four of entry, establishment, and exit of infectious agents).
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Direct damage: Toxins, Enzymes, Lysis Indirect damage: Host response is inappropriate and excessive
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Examples of portal of exit (step five of entry, establishment, and exit of infectious agents).
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Respiratory tract, Salivary glands, Skin cells, Fecal matter, Urogenital tract, Blood
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Please select characteristics exhibited by endotoxins, but not exhibited by exotoxins.
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Composed of lipopolysaccharide, Released only by gram-negative bacteria, Heat stable, Fever-inducing
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Please select characteristics exhibited by exotoxins, but not exhibited by endotoxins.
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Require very small doses to cause toxic effects, Secreted from a living cell, Have very specific targets
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Please choose the statement that describes the initial acquisition and development of normal microbiota.
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A newborn acquires normal microbiota during the birthing process and through contact with family, health care providers, food, and their environment.
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Please choose the statement that best describes the benefits of microbial antagonism to the human host.
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Microbial antagonism occurs when members of the normal microbiota prevent pathogens from colonizing and becoming established in the body.
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Please select the body sites that remain free of normal microbiota.
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Kidneys, Brain, Uterus, Bones
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The primary habitat in the natural world from which a pathogen originates is its ________
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Reservoir
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An infection that is acquired or develops during a person's stay in the hospital is a _________ infection.
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Nosocomial
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Please choose the answer that best fills in the blanks of this sentence in the correct order. A ________ infectious disease, such as a urinary tract infection, is not transmitted from person to person, whereas an infectious disease which is transmitted from one person to another, such as influenza, is referred to as a ________ infectious disease.
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noncommunicable, communicable
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The study of the frequency and distribution of disease in defined human populations is known as _________.
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Epidemiology
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TRUE/FALSE Reservoirs are always humans or other animals.
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False
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A disease pattern in which the number of new cases is increasing beyond what is expected for the population
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Epidemic
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A disease pattern in which the number of new cases is increasing beyond what is expected, not just in a limited geographic area or population, but on more than one continent
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Pandemic
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A disease pattern in which occasional cases are reported at irregular intervals in random locations
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Sporadic
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A disease pattern with a relatively stable frequency over a long period of time
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Endemic
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Please select the three most prevalent types of nosocomial infections.
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Surgical site infections, Urinary tract infections, Respiratory infections
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Appearance of first early, nonspecific symptoms
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Prodromal stage
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. Microorganism is multiplying rapidly and causing fever and specific disease symptoms
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Period of invasion
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Decline of symptoms and return to a state of health
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Convalescent period
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Period of time from initial contact with pathogen to appearance of very first symptoms
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Incubation period (NO SYMPTOMS)
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TRUE/FALSE Universal precautions are specifically intended for the handling of patients and specimens known to be infected with pathogens such as HIV.
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False
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Please choose the statement that best describes the use of Koch's postulates.
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Koch's postulates are used to establish that a particular microorganism causes a specific disease.
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Please match the description to the pattern of infection. More severe infection, rapid onset
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Acute infection
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Please match the description to the pattern of infection. An infection that has spread to multiple body sites and tissue fluids; no longer restricted to one body site
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Systematic infection
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Please match the description to the pattern of infection. Microbe enters the body and remains confined to a specific tissue
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Localized infection
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Please match the description to the pattern of infection. An infection that progresses and persists over a longer period of time; symptoms often less severe
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Chronic infection
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Please match the description to the pattern of infection. A subsequent infection with a different microbe that may occur following an initial infection
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Secondary infection
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Please order the four steps of Koch's postulates as they would normally be applied. Reisolate the disease agent from the test subject which now shows signs of disease. Isolate the suspected microbe from an infected host and cultivate it in pure culture in the laboratory. Inoculate a susceptible healthy subject with the laboratory isolate of the potential pathogen and observe the resultant disease. Find evidence of a particular microbe in every case of a particular disease.
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1. Find evidence of a particular microbe in every case of a particular disease. 2. Isolate the suspected microbe from an infected host and cultivate it in pure culture in the laboratory. 3. Inoculate a susceptible healthy subject with the laboratory isolate of the potential pathogen and observe the resultant disease. 4. Reisolate the disease agent from the test subject which now shows signs of disease.
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Please read the following scenario: "Molly developed gastroenteritis after eating raw cookie dough. Upon culture of her stool, the causative agent was shown to be Salmonella typhimurium. Presumably the Salmonella was in the uncooked eggs in the raw cookie dough." What is the reservoir for the infection in this case?
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The chickens from which the eggs came
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Please choose the statement that provides correct information about zoonoses.
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70% of the new emerging infections seen today are zoonoses.