Ch. 23 Microbio

________ is the growth of microorganisms NOT normally present within a host. A. Disease B. Virulence C. Infection D. Pathogenicity

Infection

Ouch, you have a gum infection. After flossing you notice blood on the floss and tootbrush. Some bacteria have now entered your blood. This would be called:

bacteremia

These pathogens show little difference in the number of cells required to kill 100% of the population as compared to 50% of the population

highly virulent pathogens

Breaks down tight junctions and connective tissue

hyaluronidase

Produced by Clostridium perfringens and is also called alpha toxin. Digests phospholipids

lecithinase

A patient who has been hospitalized with uncontrolled muscle spasms has probably been infected with bacteria that secrete a(n) A. superantigen. B. enterotoxin. C. membrane disrupting toxin. D. neurotoxin.

neurotoxin

Which of the following is NOT a physiological effect of endotoxin exposure? A. tissue necrosis B. hemorrhagic shock C. rapid increase in the numbers of lymphocytes E. fever

rapid increase in the numbers of lymphocytes

Kills nucleated cells and acts as a hemolysin. Produces a membrane spanning pore

staphylococcal alpha toxin

Causes RBC to break down (hemolysis)

streptolysin S and O

Leads to systemic shock

toxic shock toxin

Measure of pathogenicity

virulence

Under what conditions could a member of the gut microbiota become a pathogen?

Any situation that reduces the normal gut flora (giving an organism a chance to take over and cause illness) or allow a member of the normal gut flora to access other body sites could allow it to cause disease. Ruptured appendix Antibiotics Salmonella

True or False: Anthrax causes a localized infection when acquired through the mucous membranes of the lungs, but it causes a lethal, systemic infection when acquired through the skin. TRUE FALSE

False

True or False: Endotoxins are the secreted products of living cells, whereas exotoxins are cell bound and released in large amounts ONLY when the cells lyse. TRUE FALSE

False

Which of the following enzymes breaks down the "glue" that holds cells together? A. Hyaluronidase B. Streptokinase C. Fibrinolysin D. Collagenase

Hyaluronidase

What are leukocidins? A. Molecules that destroy the complement proteins B. Molecules that can degrade IgA C. Molecules that are capable of destroying phagocytes

Molecules that are capable of destroying phagocytes

Leads to an overproduction of cAMP and the secretion of chloride and bicarbonate ions from the small intestinal cells into the intestinal lumen

cholera toxin

Staphylococcus aureus produces ________, leading to fibrin clots that protect them from attack by host cells. A. collagenase B. coagulase C. lipase D. amylase

coagulase

The skin is an effective barrier to the penetration of microorganisms because it has sebaceous glands that secrete ________ and ________, lowering the acidity of the skin to ________ and inhibiting colonization by many pathogens. A. salts / water / pH 7.4 B. hydroxyl ions / salts / pH 6 C. lactic acid / fatty acids / pH 5 D. salts / hydroxyl ions / pH 7.4

lactic acid / fatty acids / pH 5

Which of the following is NOT a constituent of the LPS subunits? A. membrane-distal O-polysaccharide B. membrane-proximal core polysaccharide C. lipid A D. lipid B

lipid B

Adherence factors include ALL of the following EXCEPT A. capsule. B. fimbriae. C. flagella. D. lipopolysaccharide.

lipopolysaccharide

Streptocoocus pyogens utilizes M protein and ________ to form microfibrils that facilitate attachment to host cells. A. lipoteichoic acid B. mucus C. plaque D. lipid A

lipoteichoic acid

Measles viruses are capable of inactivating host defenses by A. destroying complement proteins. B. producing superantigens. C. suppressing the immune system. D. producing leukocidins.

suppressing the immune system

Which of the following is correct pertaining to endotoxins? A. Made up of the lipid A portion of the LPS complex. B. Produced by both Gram positive and Gram negative cells. C. Considered moderately toxic and requires a large amount to be fatal. D. Often encoded on bacterial plasmids. E. Can lead to fever, diarrhea, and vomiting.

1. Made up of the lipid A portion of the LPS complex 2. Considered moderately toxic and requires a large amount to be fatal 3. Can lead to fever, diarrhea, and vomiting

Which of the following would be correct about our microbiota? A. The lower respiratory tract typically lacks microflora in healthy individuals. B. Microflora typically are found on all surfaces of the respiratory tract. C. The bladder is only sterile in males. D. Women are more prone to urinary tract infections. E. Streptococci and Staphylococci are the most common causes of urinary tract infections.

1. The lower respiratory tract typically lacks microflora in healthy individuals 2. Women are more prone to urinary tract infections

How can capsules enable bacteria to evade the immune system? A. A capsule is a superantigen that distracts the immune system. B. Capsules block the complement biding sites on the surface of the pathogen. C. Capsules can bind up IgA, rendering it inactive.

Capsules block the complement biding sites on the surface of the pathogen.

Native peoples often experience an increase in the incidence of dental caries after they are introduced to imported processed foods. This finding could be explained by the fact that __________. A. Lactobacilli require sucrose in order to form biofilms on tooth surfaces. B. Sucrose and other purified sugars cause pitting of the tooth surfaces. C. Only purified sucrose and fructose can be fermented or produce acids in the oral cavity. D. Sucrose is required for the production of adhesive dextran by Streptococcus mutans.

Sucrose is required for the production of adhesive dextran by Streptococcus mutans

How are superantigens different from other types of exotoxins? A. Superantigens only act against host neurons. B. Superantigens cause an overstimulation of the host immune system. C. Superantigens are comprised of two functional domains. D. Superantigens must be endocytosed into a target cell before becoming active.

Superantigens cause an overstimulation of the host immune system

Which of the following defense systems would be involved in fighting a viral pathogen? A. Complement system B. T lymphocytes C. Phagocytosis D. Humoral immunity

T lymphocytes

True or False: Hormones that are produced under stress conditions can inhibit normal immune responses and may play a role in stress-mediated disease. TRUE FALSE

True

Which of the following microorganisms actually grows inside the macrophage? A. Legionella B. Tuberculosis bacterium C. Streptococcus pneumoniae D. Shigella E. Leishmania

Tuberculosis bacterium

Microorganisms usually found associated with human body tissue

normal microbial flora

Healthcare-associated infections are also called A. opportunistic pathogenic infections. B. attenuated infections. C. virulent infections. D. nosocomial infections.

nosocomial infections

Bacteria make up about ________ the weight of fecal matter. A. one-fourth B. one-third C. one-half D. one-fifth

one-third

Which of the following mammals is largely resistant to rabies infection? A. raccoons B. skunks C. opossums D. humans

opossums

When would endotoxins be released from a bacterial cell? A. When the cell dies B. When the cell attaches to a host cell in the human body C. When the cell moves toward a energy source D. During bacterial conjugation

When the cell dies

Microbial parasites

pathogen

The ability of a parasite to inflict damage on the host

pathogenicity

Which of the following is NOT one of the three categories of exotoxins? A. cytolytic toxins B. AB toxins C. perforating toxins D. superantigen toxins

perforating toxins

Normal flora ________ colonization of pathogenic organisms. A. promote B. prevent C. maintain D. accelerate

prevent

Which of the following is NOT found in the gastrointestinal tract of a healthy individual? A. protists B. Clostridium C. Bacteroides D. Bacteroidetes

protists

One microenvironment of the skin is an area where glands produce an oily substance called: A. mucus. B. sebum. C. fimbrae. D. lipid A.

sebum

Dissolves fibrin clots

strepokinase

A person who attended a picnic early in the day develops a very high fever and is unresponsive by the evening. This person most likely has been exposed to a(n) A. enterotoxin. B. superantigen. C. membrane disrupting toxin. D. cytotoxin.

superantigen

Karen stepped on a rusty nail while walking her dog barefoot. She needs to be treated to prevent damage by which exotoxin? A. tetanus exotoxin B. hemolysin C. cholera exotoxin D. botulinum exotoxin

tetanus exotoxin

Binds to inhibitory interneurons blocking the release of glycine. Causes spastic paralysis

tetanus toxin

All of the following areas of the human body should be microbially sterile EXCEPT __________. A. the lymphatic system B. the respiratory tract C. the bloodstream D. the nervous system

the respiratory tract

The lipid A portion of LPS is responsible for ________, and the polysaccharide fraction makes the complex ________ and ________. A. virulence / insoluble / immunogenic B. toxicity / water-soluble / immunogenic C. toxicity / insoluble / pathogenic D. virulence / nonpolar / insoluble

toxicity / water-soluble / immunogenic

All AB toxins have which of the following? A. hemolytic activity B. two subunits C. lipid A D. immunogenic properties

two subunits

Certain traits that allow pathogens to create infection and cause disease are termed A. hyaluronidases. B. collagenases. C. streptokinases. D. virulence factors.

virulence factors

Which of the following is NOT produced by microorganisms in the gut of humans? A. vitamin B12 B. vitamin K C. vitamin C D. CO2

vitamin C

Organisms that colonize skin __________. A. are never pathogenic B. are mostly gram-positive bacteria C. are always aerobes D. do not include eukaryotes

are mostly gram-positive bacteria

An exotoxin that has the ability to kill or damage host cells is referred to as a(n) A. A-B toxin. B. cytotoxin. C. neurotoxin. D. enterotoxin. E. superantigen.

cytotoxin

Which of the following would be the first sign of an infection that resulted in the release of endotoxin? A. Weakness B. Nausea C. Pain D. Fever

Fever

How does the protozoan Trypanosoma evade detection by the immune system? A. It can change the surface antigens frequently, preventing the immune system from tracking it. B. It can resist oxidation inside macrophages. C. It produces a capsule which is composed of polysaccharides similar to those found in the host. D. It prevents phagosome-lysosome fusion.

It can change the surface antigens frequently, preventing the immune system from tracking it.

Why is a release of endotoxin into the bloodstream potentially deadly? A. It causes necrosis of the liver. B. Endotoxin can quickly enter the brain from the bloodstream, causing brain damage. C. It can lower blood pressure and cause the patient to go into shock. D. It results in dehydration of the patient.

It can lower blood pressure and cause the patient to go into shock

Which of the following is FALSE about the Limulus amoebocyte test? A. It is an endotoxin assay. B. It is an exotoxin assay. C. It uses lysates of amoebocytes from the horseshoe crab. D. It detects endotoxins in cerebrospinal fluid.

It is an exotoxin assay.

Discuss two reasons why the lower respiratory tract is not normally colonized with microbiota

It is virtually free of microorganisms, mainly because of the efficient cleansing action of the epithelium which lines the tract. Any bacteria that does reach the lower respiratory is removed by coughing, sneezing, swallowing, etc. Mucus traps microbes and prevents them from moving further through the respiratory system. Cilia sweep the trapped microbes up and away from the lower respiratory tract. The air-flows slows as it moves through the respiratory tract. The abundance of macrophages in the lungs remove most microbes that arrive there.

True or False: Helicobacter pylori is the MOST common single organism found in the stomach. TRUE FALSE

True

The decrease or loss of virulence of a pathogen is referred to as

attentuation

Which of the following is correct pertaining to cytolytic toxins? A. are extracellular proteins. B. cause cell lysis and death. C. damage host cytoplasmic membrane. D. normally form part of the cell wall. E. can lead to pus production.

1. are extracellular proteins 2. cause cell lysis and death 3. damage host cytoplasmic membrane 4. can lead to pus production

Which type of mutation would have a more lethal effect on the bacterium? A mutation preventing production of an exotoxin or a mutation prevention production of the endotoxin? Explain.

An endotoxin because the complex phospholipid-polysaccharide macromolecules form an integral part of the outer membrane. They need the outer membrane for their survival.

Explain why women of childbearing age often develop a vaginal yeast infection when they are on antibiotics

Antibiotics can destroy "good bacteria" in your vagina. This bacteria helps to keep the body's natural yeast population in check. When the good bacteria gets destroyed, yeast can multiply and potentially cause a yeast infection. This lowers the amount of lactobacilli that help keep the pH of the vagina slightly acid. Yeast can take advantage of the rising pH and increase their growth leading to yeast infection.

Which domain of the A-B toxin binds to cell surface receptors on the host cell? A. A domain B. B domain C. A-B toxins do not bind to cell surfaces. D. Both the A and B domains have the ability to bind to cell surface receptors.

B domain

Which cells directly attack abnormal cells in the body? A. Helper T cells B. B cells C. Cytotoxic T cells D. Phagocytes

Cytotoxic T cells

An adult usually has an extensive system of normal flora associated with our ______________ and this prevents botulism bacteria from attaching and releasing their _______________ causing toxin. A. Digestive tract/ spastic paralysis B. Respiratory tract/flaccid paralysis C. Urogenital tract/spastic paralysis D. Digestive tract/flaccid paralysis E. Skin/spastic paralysis

Digestive tract/flaccid paralysis

Which of the following is FALSE about the influence of age on susceptibility to infection? A. Infectious diseases are more common in the very old and very young. B. Enlargement of the prostate in men over 50 leads to suppression of the immune response. C. Before the development of adult flora, pathogens have a greater opportunity to become established and cause disease. D. Anatomical changes associated with age may encourage infection.

Enlargement of the prostate in men over 50 leads to suppression of the immune response

Endotoxins are also known as A. Lipid A. B. cytokines. C. interleukin-1. D. prostaglandins.

Lipid A

Meningitis and gonorrhea are caused by A. Neisseria species. B. Pseudomonas species. C. measles virus.

Neisseria species.

Which of the following does NOT occur during the development of dental caries? A. Streptococcus mutans produces dextran when sucrose is present. B. Oral microflora produce high concentrations of exoenzymes when sucrose is present. C. Lactic acid dissolves calcium phosphate, causing decalcification of the tooth enamel. D. Oral microflora produce high concentrations of organic acids.

Oral microflora produce high concentrations of exoenzymes when sucrose is present.

According to the animation, antibodies interact with which innate defenses? A. The complement system B. Phagocytosis, inflammation, and the complement system C. First-line defenses D. Phagocytosis E. Inflammation F. Phagocytosis and the complement system

Phagocytosis and the complement system

Describe two situations in which a pathogen can act as an opportunistic pathogen

Staphylococcus aureus occurs as commensal on human skin but may cause staph infections. Pseudomonas aeruginosa is the most common cause of burn and external ear infections, and is the most frequent colonizer of medical devices (e.g.catheters).

Which of the following virulence factors would be found in Staphylococcus aureus? A. Streptokinase B. Hyaluronidase C. Collagenase D. Staphylokinase

Staphylokinase

Which of the following statements about the role of diet as a risk factor is TRUE? A. The number of organisms necessary to induce cholera is greatly increased when Vibrio cholerae is ingested in food. B. Increasing the amount of sucrose in your diet decreases the development of dental caries. C. Diets high in protein and calories alter the normal flora, increasing the host's susceptibility. D. The absence of a particular dietary substance may prevent disease by depriving a pathogen of critical nutrients.

The absence of a particular dietary substance may prevent disease by depriving a pathogen of critical nutrients.

How does a capsule help certain bacteria evade detection by the immune system? A. Capsules have the ability to destroy antibodies secreted by the immune system. B. The capsule makes the bacterium too sticky to be phagocytosed by the immune cells. C. The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign. D. Capsules allow the bacteria to stick together, creating a larger mass that is too big for immune cells to engulf.

The capsule is composed of polysaccharides that are similar to those found in the host; thus, the immune system does not recognize it as foreign.

Which of the following would happen if you accidentally drink water contaminated with Clostridium tetani? A. The pathogen would be killed by the acidity of the stomach. B. The pathogen would outcompete the well-developed intestinal flora. C. The pathogen would grow and produce tetanus toxin. D. Death from tetanus would occur.

The pathogen would be killed by the acidity of the stomach.

How are immune cells able to detect foreign pathogens? A. They detect foreign, unfamiliar chemical substances released by the invading cells. B. They are able to detect structures on the surfaces of foreign cells that are not found in the host. C. They can compare the DNA sequences from the foreign cells to host DNA.

They are able to detect structures on the surfaces of foreign cells that are not found in the host.

How do fibrinolysins enhance a pathogen's virulence? A. They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin. B. They destroy the molecules that hold cells together. C. They destroy the fibers that are found at the base of superficial tissues, allowing for deeper penetration by the pathogen.

They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.

How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system? A. They cause the immune system to destroy IgA antibodies. B. They cause fever, which destroys the complement proteins. C. They cause the immune system to turn on itself. D. They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen.

They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen

A researcher wanted to determine the LD50 (lethal dose50) for a newly-isolated bacterial pathogen. Mice were inoculated with diluted cultures containing between 101 and 107 cells. After two days, all of the mice had died, EXCEPT for the uninoculated controls. Which of the following is the most likely explanation? A. Mice are not good model animals for this pathogen. B. This pathogen is highly virulent in mice. C. The pathogen has become attenuated. D. The pathogen has a very high LD50

This pathogen is highly virulent in mice.

Our body is protected by the ___________ associated with epithelial tissues unless a pathogen can use _____________ to break through this barrier. A. Gap junctions/ hyaluronidase B. Tight junctions/ streptolysin C. Desmosome/ coagulase D. Tight junctions/ hyaluronidase E. Gap junctions/ lethicinase

Tight junctions/ hyaluronidase

Following exposure to a pathogen, events leading to disease—in the correct order—are A. adherence, virulence, invasiveness B. adherence, invasion, infection, toxicity C. invasion, adherence, virulence D. invasion, adherence, toxicity, infection

adherence, invasion, infection, toxicity

Which of the following are susceptible to HIV infection? A. all primates B. all animals that have the CXCR4 and CCR5 proteins C. all animals that lack the CXCR4 and CCR5 proteins D. only humans

all animals that have the CXCR4 and CCR5 proteins

A hard-core, steak-loving athlete has fallen for a vegan. In order to maintain harmony in their relationship, the athlete has willingly given up meat and all animal products in their diet. They are now on a strictly plant-based diet. What would you expect to see? A. a change in the gut microbiota B. loss of microbiota that secrete proteases C. an increase in microbes that secreate cellulases D. all of the above

all of the above

Which of the following healthcare procedures may unintentionally introduce microorganisms into the patient? A. catheterization B. surgery C. spinal puncture D. all of the above

all of the above

Which of the following will happen after a person takes an antibiotic orally? A. The growth of normal flora will be inhibited. B. The growth of pathogens will be inhibited. C. Opportunistic microorganisms such as antibiotic-resistant Staphylococcus will become established. D. all of the above

all of the above

As you move through the digestive tract the amount of available oxygen _____________ while the pH _____________. A. increases / increases B. decreases / decreases C. increases / decreases D. decreases / increases

decreases / increases

Extensive growth of the streptococci in a thick bacterial layer on acidic glycoproteins on the teeth is called: A. dental plaque. B. dental caries. C. dental biofilm. D. periodontitis.

dental plaque

Antibiotics can alter gut microbiota. Which of the following is most likely to also alter gut microbiota? A. amount of sunlight a person is exposed to B. diet C. soaps, shampoos and deodorants D. exercise

diet

Inactivates elongation factor 2 thus blocking protein synthesis

diphtheria toxin

Damage or injury to the host that impairs host function

disease

The diphtheria exotoxin is an A-B toxin that __________. A. is encoded for by genes in the chromosome of Corynebacterium diphtheriae cells B. is found only in Corynebacterium diphtheriae cells that have been infected with lysogenic bacteriophage β C. is found in all Corynebacterium diphtheriae cells D. causes host cell lysis

is found only in Corynebacterium diphtheriae cells that have been infected with lysogenic bacteriophage β

Causes vomiting and diarrhea

enterotoxin A

Factors that enhance an organism's ability to adhere to host tissues include __________. A. lipopolysaccharide B. peptidoglycan C. fimbriae D. adherence enzymes

fimbriae

Which of the following is more likely to cause urinary tract infections? A. fimbriated strains of Escherichia coli B. non-fimbriated strains of Escherichia coli C. both fimbriated and non-fimbriated strains of Escherichia coli D. None of the answers are correct.

fimbriated strains of Escherichia coli

Botulinum toxin and tetanus toxin BOTH block the release of neurotransmitters, but botulinum toxin causes ________ whereas tetanus toxin causes ________. A. severe diarrhea / tissue necrosis B. tissue necrosis / severe diarrhea C. spastic paralysis / flaccid paralysis D. flaccid paralysis / spastic paralysis

flaccid paralysis / spastic paralysis

The image below shows a colorized transmission electron micrograph of Clostridium difficile, a Gram-positive, anaerobic member of the gut microbiota. Based on the image and information provided, which features contribute to the spread of C. difficile in a hospital environment? A. waxy walls B. hardy endospores C. ability to tolerate oxygen in the environment D. ability to attach to surfaces with fimbriae

hardy endospores

According to the animation, B cells interact directly with A. phagocytes. B. inflammation. C. helper T cells. D. the complement system.

helper T cells

Mucous membranes are a part of A. adaptive defense. B. the complement system. C. innate defense. D. humoral immunity. E. cell-mediated immunity.

innate defense

A person would be most at risk of infections if he or she __________. A. is a 70-year-old alcoholic whose spouse just died B. is an active 30-year-old going through a divorce C. eats fast food every day of the work week and sleeps 9 hours a night D. is a breast-feeding infant with a vegetarian mother who runs 5 miles a day

is a 70-year-old alcoholic whose spouse just died