MCB 100 exam 2 pre-lecture questions

Lance's physician administered a tuberculin test to determine whether Lance had been infected during his flight from South Africa. How was this test performed?

A small amount of cell wall material from Mycobacterium tuberculosis was injected into Lance's forearm skin.

Which is the vector of Rickettsia rickettsia?

A tick

In the case of gastrointestinal disease, how can an intoxication be distinguished from an infection?

An intoxication is usually apparent shortly after ingestion, while an infection takes longer

Lysogeny is associated with all of the following EXCEPT __________.

Animal viruses

Name a structural difference between animal viruses and bacteriophages.

Animal viruses may be enveloped; bacteriophages are always naked.

How are fungal and animal cytoplasmic membranes different from each other?

Fungal cytoplasmic membranes contain ergosterol, while animal cytoplasmic membranes contain cholesterol.

What is the difference between Gram-positive bacteria and mycoplasmas?

Gram-positive bacteria have thick cell walls, while mycoplasmas lack cell walls.

How will the prescribed penicillin kill S. pyogenes that is causing Shelly's infection?

Penicillin will interfere with peptidoglycan synthesis, ultimately weakening the cell wall and leading to cellular lysis.

A(n) ________ is a virus that infects bacterial cells.

bacteriophage

The outermost layer of a virion fulfills which of the following functions of the virus?

both protection and recognition

In which of the following methods of prokaryotic reproduction does the parental cell remain intact after the reproduction event to continue the process?

budding

What does it mean for a cell to be haploid?

cell has only one set of chromosomes

Although many people along the Mississippi, Missouri and Ohio River valleys have been exposed and test positive for histoplasmosis, most (95%) are asymptomatic. How do they clear the organism from their bodies?

cell-mediated immunity

In a section that will be a brief survey of the prokaryotic bacteria, you want to give an overview of the multiple groups of bacteria and representative bacteria within each group. The groupings have been developed based on many characteristics of the bacterial cells and attempt to group together different species with similar cellular characteristics. Cellular morphology, cell wall composition, and metabolism have historically been used as means to roughly group bacteria together into different classes and genera. Current technologies have been expanding and reorganizing these groupings based on lipid content and genomic characterizations. Which of the following characteristics would NOT be used to aid in classifying a newly discovered bacterial species?

cellular size

How can this disease best be categorized?

contagious and chronic

It is estimated that _____ of the world's population may be infected with tuberculosis.

33%

What percent of people harbor Candida naturally in their body without showing any signs or symptoms?

40-80%

Which of the following lists the criteria for a diagnosis of Staphylococcus aureus infection?

Staphylococcus aureus cultures are coagulase positive, catalase positive, yellow colonies that are composed of Gram-positive cocci.

Which practice would NOT be a good way to prevent foodborne botulism?

Storing canned foods at room temperature.

Which of the following bacteria is the primary cause of necrotizing fasciitis?

Streptococcus pyogenes

Which genus of high G + C Gram-positive bacteria synthesize antimicrobials such as chloramphenicol, erythromycin, and tetracycline?

Streptomyces

What area of the country has the highest incidence of Rocky Mountain Spotted Fever?

The Appalachian mountains and Ozarks

Why does tuberculosis involve months of antibiotic treatment?

The bacteria grow very slowly.

A patient infected with a protozoan parasite who also exhibits congestive heart failure is most likely in the final stages of which of the following diseases?

Chagas' disease

Which of the following habits might best prevent infection with Candida?

Change wet diapers often.

How are patients typically infected with listeriosis?

Contaminated food or drink

Into which type of cell are the Rickettsia introduced in the human host?

Endothelial cells

One of the best parts about working at the free clinic is being in contact with the doctors. Doctor Myers is the only full-time paid doctor; the rest all volunteer their time. Some of the doctors volunteer once a week and others only once a month, but they are all very nice and they eat their lunch with the staff and LPNs. Many of the LPNs are just starting out in their careers and so the lunches often turn into educational experiences. Today Dr. Myers is eating lunch with them, so Wanda asks her how she will tell Rebecca and Jake about the pregnancy and the C. trachomatis infection, and what treatment she will recommend for Rebecca. __________ is the treatment of choice for C. trachomatis.

Erythromycin

Which of the following is not usually used for treating tuberculosis?

Erythromycin

What is the best way to prevent nosocomial MRSA infections?

Everyone should wash their hands before eating and after contact with any potentially contaminated surface/person.

Contact with infected cats and their feces is the only mode of transmission of Toxoplasma to humans.

False

Which component of a Gram-negative cell wall can cause fever, vasodilation, inflammation, shock, and blood clotting?

Lipid A

How are lysogenic phages different from lytic phages?

The genome of a lysogenic phage is integrated into its host genome.

Sexual reproduction often involves two haploid sex cells or gametes. A smaller, mobile, male gamete typically fuses with a larger, nonmobile, female gamete. Why are the sex cells of fungi called + and -, instead of male and female?

The haploid sex cells of fungi are virtually indistinguishable from one another.

When viewed through a microscope, some fungi with branched hyphae look somewhat like plants. Why are fungi not plants?

They lack chloroplasts and therefore cannot perform photosynthesis.

How do humans acquire this disease?

This disease is most commonly acquired by inhalation.

Trypanosoma cruzi is introduced into the body by

feces containing trypomastigotes contaminating a bite wound.

Fungi exist as either unicellular yeasts or _____.

filamentous molds

Which of the following medications is typically used for superficial candidiasis in AIDS patients?

fluconazole

Diploid cells undergo meiosis producing _____.

four haploid nuclei

The ability of Vibrio cholerae to cause disease depends on a number of factors. Which of the following are general requirements for any organism to cause disease within a host?

adherence to host tissues evasion of host defenses gaining access to the host via a portal of entry

Mycobacterium tuberculosis is considered a(n) __________.

aerobe

How is tuberculosis transmitted?

aerosol droplets released by a cough or sneeze

A phage T4 particle that has lost its tail fibers will have a replication cycle that is blocked at which of the following stages?

attachment

Once infected with Trypanosoma brucei, the patient's immune system cannot clear the infection and develop immunity because the parasite

changes its glycoprotein surface antigens every time it replicates.

Which topical medication would likely be recommended for use in this case?

clotrimazole cream

What tools would the doctor use to diagnose this disease?

identification of the budding yeast in KOH-prepared samples of skin scrapings or sputum from the patient

What is the most common portal of infection for true fungal pathogens that cause systemic mycoses?

inhalation

In 90% of cases, a spotted non-itchy rash forms on the __________, particular to rickettsiosis.

palms and soles

Which structure is characteristic of Candida?

pseudohyphae

In which population might we observe a higher incidence of thrush?

the elderly

Most viruses cannot be seen by light microscopy.

true

Several species of Plasmodium cause malaria in humans.

true

In which part of the body would candidiasis present as curd-like?

vagina

Which opportunistic fungus is characterized by pseudohyphae?

Candida

Based on the lab results, which organism is most likely causing Tori's new symptoms?

Candida albicans

How does coagulase facilitate bacterial virulence?

Coagulase breaks down blood clots in which bacteria hide, releasing them so they can spread to other parts of the body.

How might an infected patient transmit listeriosis to another human?

During pregnancy.

What is empyema?

Empyema refers to a pocket of pus in between the lung and the inner surface of the chest wall.

Which of the following correctly describes the function of bacterial endospores?

Endospores are produced as resting stages of the bacterium that can survive inhospita

What is the function of endospores?

Endospores are survival structures.

Which of the following bacterial genera plays an important role in environmental nitrogen cycles?

Nitrobacter, Rhizobium, and Azospirillum

Are Clostridium botulinum vegetative cells required to be present for foodborne botulism to occur?

No, foodborne botulism is caused by the botulinum toxin produced by the bacteria, not the bacteria themselves.

Is it critical to determine the fungal agent or agents contributing to this case? Why or why not?

No. The treatment would be the same.

Which of the findings listed below support the hypothesis? Select all that apply.

Protein Levels within the ileum loop fluid are increased up to 1000 units of toxin. Histological observation indicates that morphological alternation and sloughing of epithelial cells occurs up to a maximum of 1000 units. Increasing levels of sodium, potassium, bicarbonate, and chloride ions, as well as water, are secreted as toxin concentrations are increased from 25, 50, 100, and 150 units.

The Gram stain revealed nothing that looked like bacteria and Brenda is relieved. On the other hand, since the fungi had reproductive structures, she is worried about the rest of the equipment. Brenda knows that fungal spores spread contamination readily, so she is concerned that even areas that look all right could have spores that would germinate later. Although she is pretty sure that the contaminant is a zygomycete, she knows that she will likely need to grow the fungus on the Sabouraud agar plate and send it in for genetic testing to identify the genus and species. Growing the fungus will take several days and the genetic testing can take a week or more. At lunch, Brenda checks her email. She has been following a story about an outbreak of an atypical respiratory infection in diabetic and immunosuppressed individuals. The latest news is that the infection appears to be fungal and a respiratory patient had died after the infection spread to the brain. Brenda almost chokes on her lunch; she has no reason to believe that the fungal contaminant that she just found is related to this outbreak, but the 2012 meningitis outbreak lingers in her mind. She gets right back to work looking up zygomycosis infections and what kinds of symptoms they can cause. Drag the symptoms and mode of transmission to the correct zygomycoses.

Rhinocerebral zygomycota: -fever, sinus pain, nasal discharge -inhalation of spores Gastrointestinal zygomycota: -ingestion -abdominal pain, vomitting Cutaneous zygomycota: -skin lesions -contact

Some studies have indicated that the ID50 for Vibrio cholerae can be as high as 108 organisms. Which of the following most likely explains the requirement for this relatively high ID50?

To establish infection, V. cholerae must survive the host immune response and the acidic environment of the stomach.

Which of the following is the most common parasitic disease in industrialized nations?

Trichomonas infection

Bacteria in the genus Cytophaga are capable of digesting a wide range of complex carbohydrates and are important for degrading raw sewage.

True

Various species of Streptomyces are important sources of antibiotics.

True

The nutritional requirement to oxidize amino acids and Kreb's cycle intermediates means Rickettsias are __________.

obligate intracellular parasites

Fungi that cause disease only in people with poor immunity or disrupted microbiomes are called

opportunistic fungi.

In approximately 10% of patients tubercles rupture and reactivate infection. This is known as _____ tuberculosis.

secondary

What part of the United States is endemic for RMSF?

the Appalachian region (North Carolina, Kentucky)

Which stage of sexual reproduction involves the fusion of hyphae tips from opposite mating types to produce cells with two separate nuclei?

the dikaryotic stage

What was the most likely choice for the second antibiotic this patient received?

vancomycin

Which type of leishmaniasis is most likely fatal?

visceral leishmaniasis

The definitive host of a parasite is

where the mature form of the parasite occurs.

Unicellular, spherical fungi are called

yeasts.

What is the word used to refer to diseases transmissible from animals to humans?

zoonoses

How does β-lactamase contribute to the virulence of Staphylococcus spp.?

β-lactamase breaks down penicillin and cephalosporin.

What type of organisms do phages infect?

Bacteria

How do clinicians primarily screen for tuberculosis in patients?

Tuberculin skin test

Which of the following factors would NOT contribute to the development of severe dermatomycoses?

wearing sandals

Gram-negative bacteria in the genus ________ prey on other Gram-negative bacteria.

Bdellovibrio

Which of the following would NOT be a risk factor associated with the development of histoplasmosis in people?

traveling to China

Part of the reason for Scott's acne is the overproduction of sebum. Scott's initial instinct is that shutting down production of sebum would be the quickest route to eliminating his acne; however, sebum actually plays an important role in maintaining the skin as a first line of defense against pathogens. Which of the following best describes the role of sebum as a component of the first line of defense? Select all that apply.

- Sebum forms a protective layer over the skin. - Sebum helps to keep the pH of the skin low, which inhibits the growth of microorganisms.

Dr. Smith assures Scott that although inflammation may sound scary, there are several possible options for treating Scott's moderate acne. Which of the following would be the most appropriate for Scott's case? Select all that apply.

- an oral antibiotic such as erythromycin - topical treatment with a product containing benzoyl peroxide - Clear Light, a nonchemical, light-based system

Dr. Smith prescribes oral erythromycin for Scott. She also recommends that he consider using an over-the-counter gel or cream containing benzoyl peroxide. Although this regimen should be effective at treating Scott's acne, there are some possible side effects. Which of the following are possible side effects of Scott's treatment? Select all that apply.

- excessive drying of the skin -gastrointestinal problems resulting from a reduction/elimination of normal intestinal flora

Research has indicated that during the inflammatory response to P. acnes, both the classical and the alternative complement pathways are activated. Which of the following are outcomes of activating complement pathways? Select all that apply.

- inflammation - opsonization - cytolysis

Acne is the result of the inflammatory response. In this case, the inflammation is resulting in acne that is very painful (physically and emotionally) for Scott. However, inflammation is a critical component of a normal immune response. What are the main functions of the inflammatory response? Select all that apply.

- walling off" the site of injury or infection - destroying and eliminating the invading pathogen - repairing tissue damage resulting from inflammation

Another characteristic that you want to include in the introduction is bacterial reproduction. Prokaryotic cells have only one chromosome and lack any organelles such as a nucleus, which limits the requirement for numerous cellular processes when a cell divides to form two daughter cells. In both major forms of bacterial reproduction, binary fission and snapping, the single chromosome must replicate so that each daughter cell will carry a complete chromosome. During binary fission, the cell replicates its DNA and each DNA molecule is attached to the cytoplasmic membrane. The growing cell elongates the cytoplasmic membrane, which separates the daughter DNA chromosomes. The formation of a cross wall allows for invagination of the cytoplasmic membrane. The cross wall completely divides daughter cells, which may or may not separate. Snapping division, seen in some Gram-positive bacilli, occurs when only the inner portion of a cell wall is deposited across the dividing cell. This new cross wall puts tension on the outer layer of the old cell wall. Eventually, the outer wall breaks at its weakest point with a snapping movement that tears it most of the way around. The daughter cells can then remain hanging together almost side by side being held by a small remnant of the original outer wall. Choose from the following statements the ones that correctly discuss reproduction using binary fission in a bacterial cell. Select all that apply.

-Each daughter cell is an exact copy of the other, both genetically and morphologically. -Due to the stretching of the cytoplasmic membrane, both cells will contain a complete genome.

You decide that the introduction should also discuss the extremophiles that are referred to as the archaea. These single-cell organisms are considered "extremophiles" due to their ability to survive and reproduce in environmental conditions that would be hostile for most living organisms. Archaea species have been isolated from highly acidic sulfur springs, ocean floor thermal vents with temperatures that exceed boiling, and subarctic ice well below freezing. While still considered to be prokaryotic, the archaea have numerous differences that place them apart from the bacteria. Choose the characteristics that separate the archaea from other prokaryotic cells. Select all that apply.

-The cytoplasmic membrane lipids of archaea have branched or ringform hydrocarbon chains -Archaea lack true peptidoglycan in their cell walls.

Which of the following could Tori's physician choose as a treatment for her yeast infection?

-a topical over-the-counter ointment, such as clotrimazole or miconazole -a single oral dose of fluconazole

Which of the following infections are also caused by C. albicans?

-fulminating disease -oral thrush

An indirect immunofluorescence assay is described as the CDC "gold standard serological test" for RMSF. Keeping in mind the principles behind indirect fluorescent-antibody (indirect FA) testing, which of the following characteristics contributes to its choice as the gold standard?

1-Indirect FA uses an antibody that reacts with any human antibody. 2-Indirect FA will detect R. rickettsii-specific antibodies present in the patient's serum. 3-Indirect FA is rapid, sensitive, and specific. 4-Indirect FA is more sensitive than direct immunofluorescent testing.

What percent of patients are estimated to die from the disease?

20%

What is the difference between the cell walls of Gram-positive bacteria and those of Gram-negative bacteria?

A Gram-positive bacterium has a thick layer of peptidoglycan and lacks an outer membrane.

In which of the following cases would you suspect wound botulism?

A person injures herself while gardening. Four days later she begins to feel weak and dizzy, with blurred vision and progressive paralysis.

Which of the following is definitively diagnostic for tuberculosis?

Acid-fast stain of sputum

What is listeriolysin O?

An enzyme breaks the bacteria free from the phagosome.

Although cholera can be treated with antibiotics, data suggest that antibiotic treatment alone is NOT the most effective therapy. Which of the following statements describes the most likely reason for supplementing antibiotic therapy?

Antibiotic therapy addresses only the growth of V. cholerae; it doesn't address the extreme dehydration suffered by a person infected with V. cholerae.

Why are antimicrobial drugs of limited usefulness in Bacillus anthracis infections?

Antimicrobial drugs are unable to neutralize anthrax toxin.

Which of the following habits will best prevent infection due to listerosis?

Avoid eating raw fruits and vegetables

What is the name of the vaccine given to prevent TB in countries where it is endemic?

BCG vaccine

Based on its Gram status, why are penicillin and other beta-lactam antibiotics effective against Streptococcus pneumoniae?

Beta lactam antibiotics are effective against Streptococcus pneumoniae because it is a Gram positive organism and does not have an outer membrane.

How do blastoconidia and chlamydoconidia produced by yeast differ from bacterial endospores?

Blastoconidia and chlamydoconidia are spore structures produced by budding in yeasts, whereas bacterial endospores are produced by bacteria under extreme conditions.

What is the most likely cause of this couple's disease?

Campylobacter jejuni

Mycobacterium tuberculosis is a serious pathogen with a variety of unusual structural features. Some of these cellular structures contribute to its virulence (pathogenicity) Match the following virulence factors with a structure of Mycobacterium responsible.

Cord factor: Toxicity to infected cells, resistance to neutrophil attack Mycolic acid: persistence in tubercles, transmission in dried respiratory aerosols Pilus: attachment to tissues

Match the following properties of Mycobacterium with the structural feature responsible for each characteristic.

DNA structure: High G+C Mycolic acid: Slow growth, dissecation-resistance, acid-resistance Thick peptidoglycan wall: Bacillus shape, gram-positive

The name Propionibacterium is derived from the fact that the organism produces propionic acid during fermentative metabolism. Which of the following statements about fermentative metabolism is true?

Fermentation produces significantly less ATP than aerobic respiration; however it generates NAD+, which can be used in glycolysis.

Which of the following statements best describes why the treatment for Tori's fungal infection may result in side effects to her own cells?

Fungal cells and human cells have a nucleus, multiple organelles, and 80S ribosomes for protein synthesis

What is the difference between fungal spores and bacterial endospores?

Fungal spores are reproductive structures, while bacterial endospores are survival structures.

Which of the following is multicellular, chemoheterotrophic, and has a cell wall?

Histoplasma

This disease is also known as Spelunker's Disease and Cave Disease. What is the most likely cause of Nate's illness?

Histoplasma capsulatum

What is the most likely cause of this man's current health problems?

Histoplasma capsulatum

Streptococcus pneumoniae is found as part of the normal microbiota of the mouth and pharynx and yet can cause disease in some people when it is inhaled into lungs. Why do you think this is?

If Streptococcus pneumoniae is inhaled from the nasopharynx into lungs damaged by a previous viral infection or in an immune compromised person, it can flourish.

The BCG vaccine is available to immunize people against tuberculosis. Had Lance been vaccinated, he would not have been concerned about becoming infected on the airplane. Why was he NOT vaccinated?

Immunized patients have a positive skin reaction when tested, even if they have not been infected with Mycobacterium tuberculosis. Such "false positive results" hinder the work of epidemiologists trying to track the spread of the disease.

From the preliminary analysis, it would appear that individuals who consumed barbecue with Bubba-Qs sauce had the highest attack rate, followed by the dry-rubbed barbecue. Some of the individuals who said they ate the barbecue with the sauce did not become ill. Which one of the following is the most likely explanation for such an occurrence?

Individuals who became ill may have consumed larger quantities of the food than individuals who did not become ill.

The pneumococcal vaccine was made using the purified capsular material from 23 common strains of Streptococcus pneumoniae, but it is not effective against all strains. Why is this?

It cannot cover all the strains of Streptococcus pneumoniae because not all strains have the same antigens on their surface

How likely is it that other scouts were infected during the caving camp out?

It is highly likely that 90% or more of the scouts will show evidence of infection (antibody formation). Only a small percentage of these will get sick.

Why is necrotizing fasciitis so difficult to prevent?

It is part of the normal microbiota.

Today, Wanda is preparing a young woman, Rebecca, for the doctor's examination. Rebecca and her husband, Jake, are pretty sure that Rebecca is pregnant and they are very excited about becoming parents. Wanda asks a series of background questions, and then takes the woman's temperature, weight, and blood pressure. Dr. Myers comes in, introduces herself, and tells the young woman that she will be doing a pelvic exam with Pap smear, along with the pregnancy test. Wanda gets the supplies ready for the doctor, gives the girl a gown, and steps out of the room. After the examination, Dr. Myers asks Rebecca and Jake to make a follow-up appointment to discuss the results of the tests and, if appropriate, to make a prenatal care plan. At home that night, Wanda returns to her studies of the Chlamydia group of bacteria. Drag the symptoms and infectious agent to the correct disease.

Lymphogranuloma venereum Chlamydia trachomatisinitial lesion followed by buboes Pneumonia Chlamydia pneumoniae malaise and cough Ornithosis Chlamydia psittaci flulike symptoms

__________ is an antiphagocytic factor and helps S. pyogenes attach to nose and throat cells.

M protein

What type of arrangement occurs when bacilli divide by snapping division?

Palisades and V-shapes

If ampicillin is the prescribed treatment for listeriosis, why might a physician instead prescribe trimethoprim-sulfamethoxazole?

Patients may be allergic to penicillins.

Which of the following is a characteristic of biological transmission from Dermacentor to a human host?

R. rickettsii is transmitted to the human host during a bite, when tick saliva enters the wound.

What disease does Paul suspect Ron might have contracted?

Rocky Mountain spotted fever

Disease research and epidemiology bring together many different facets to help us better understand disease pathology and spread. Which of the following statements are true? Select all that apply.

Some pathogens are able to cause disease within a host without penetrating the body. The interactions that occur between a microbe and host influence the evolution of both. Bacterial exotoxins can be altered to create toxoids, which can be used to produce protective immunity in a host.

What are flexible, spiral-shaped bacteria called?

Spirochetes

Arrange the statement of events below in the order that best describes the sequence of events in the pathology of Clostridium perfringens poisoning once contaminated food has been ingested.

Sporulation and lysis of vegetative cells result in the release of CPE. CPE binds to Claudine receptors of the tight junctions of intestinal epithelia. Absorption of fluid and ions across the epithelia is inhibited. Formation of the CPE-claudin complex results in active pore formation. Calcium ion influx results in activation of calpain. Cellular death and loss of epithelial layer of intestinal villi result in fluid secretion into lumen and diarrhea. Increased myoelectrical activity of intestine leads to serve cramping.

What type of arrangement forms when multiple planes of division occur randomly in cocci?

Staphylococci

Scott's pimples result from the inflammatory response generated in his hair follicles. The statements below describe events that occur during this response. Place the following statements in the chronological order that best describes the sequence of events leading to the appearance of acne.

The overproduction of sebum resulting from the hormonal changes that Scott is experiencing is the initial event responsible for his acne. P. acnes is able to utilize the glycerol in sebum for fuel; in the process of doing so, it produces free fatty acids. These fatty acids lead to the production of inflammatory cytokines, which lead to vasodilation and increased vessel permeability. These changes allow for immune cells to move into the follicle. As the immune cells work to eliminate P. acnes, dead cells, bacterial waste, and pressure (from the massive influx of cells) will build. This ultimately distends the follicle. If great enough, this buildup will be visible on the skin as a pus-containing papule.

What effect will the penicillin have on Shelly's cells?

The penicillin will not have any impact on Shelly's cells because it targets peptidoglycan, which is found only in bacteria.

You have isolated a bacterium that contains a prophage. Which of the following is true concerning the prophage?

The phage is in the lysogenic cycle.

Streptococcus pneumoniae was originally named Diplococcus pneumoniae. Why was the genus name Diplococcus originally given to this organism?

The prefix "di-" means two, and these organisms are usually found in pairs under the microscope.

RMSF results from the interactions that occur between the R. rickettsii pathogen and the host. The infection results from a coordinated series of events that ultimately result in disease. Apply your knowledge of bacterial pathogenesis and the symptoms of RMSF to predict the order of events that occur during RMSF.

Tick bites transmit R. rickettsii into bloodstream.Tick bites transmit R. rickettsii into bloodstream. R. rickettsii travels throughout the body via the blood and lymph systems.R. rickettsii travels throughout the body via the blood and lymph systems. R. rickettsii invades endothelial cells of blood vessels.R. rickettsii invades endothelial cells of blood vessels. R. rickettsii multiplies within host cells.R. rickettsii multiplies within host cells. Blood begins to escape from vessels as a result of increased vascular permeability.Blood begins to escape from vessels as a result of increased vascular permeability. Symptoms, such as macular rash develop

Which might be the best way to prevent getting infected by Rickettsia rickettsia?

Use tick repellants and remove ticks quickly.

The physical symptoms of cholera present only after a specific series of events has taken place. What is the most likely sequence of events in the pathogenesis of V. cholerae? Place the following statements in the order that best reflects the chronology of events during V. cholerae infection.

V. cholerae is ingested via contaminated water V. cholerae survives passage through the stomach and enters the intestines V. cholerae attaches via pili V. cholerae release cholera toxin The host intestinal cells are destroyed, resulting in a profuse watery diarrhea V. cholerae exits the host via the feces

Which of the following are properties of exotoxins? Select all that apply.

Very small amounts of exotoxin can be lethal. Exotoxins target specific cellular structures or molecules. Exotoxins are protein molecules.

How do pseudohyphae in yeasts differ from vegetative hyphae in filamentous fungi?

Yeasts use pseudohyphae to invade host tissue, whereas filamentous fungi use their vegetative hyphae for obtaining nutrients.

Characterizing the fungal groups. Based on the microscopic image in Part B, the organism appears to belong to the division __________.

Zygomycota

When Wanda sees Rebecca and Jake on the patient schedule two days later, she looks at the test results in the file. Rebecca is pregnant and Wanda knows the couple will be very happy about that, but Wanda also sees that Rebecca has a C. trachomatis infection. Wanda knows from her reading that these infections are often asymptomatic in women, but it must be treated or it could cause a problem for the baby. Trachoma __________.

is the leading cause of nontraumatic blindness in humans is an infection of conjunctiva can be passed to a child during birth can be caused by introduction of bacteria into the eye via a fomite in adults

What is the name of the antifungal drug that Nate is taking?

ketoconazole

A primary infection with Mycobacterium tuberculosis typically occurs in the

lungs

Cycles of fever which recur every 48 hours is characteristic of

malaria.

Which of the following symptoms is LEAST characteristic of Clostridium perfringens food poisoning?

moderate vomiting and fever

Analysis of the second swab has confirmed that the causative organism is Streptococcus pyogenes, a gram-positive organism. Imagine that you are the technician looking at the Gram stain from Shelly's culture. What would you expect to see as you look through the microscope?

purple, spherical-shaped organisms arranged in chainlike formations

A microbiologist is making agar plates in which to grow bacteria. She can get the agar from

red algae.

One of the primary reasons the disease is able to evade the body's immunity is that it __________.

resists digestion by phagocytes

A bacterial species with spherical cells that have random planes of cell division will form which of the following arrangements?

staphylococci

One of the virulence factors produced by Group A Streptococcus is __________, which can kill neutrophils, the immune system's first responders.

streptolysin S

The IV regimen administered by Ron's doctors is consistent with the CDC's recommendation that doxycycline be administered when RMSF is suspected. Apply your knowledge of RMSF to choose the most likely reasons behind this recommendation.

-A delay in treatment can lead to complications that include respiratory, cardiac, and renal failure. - Most tests that can definitively identify R. rickettsii are not very effective early in infection -The symptoms of RMSF are similar to those of several other infections, making definitive diagnosis difficult. -Without prompt treatment, RMSF can have a mortality rate as high as 20%.

As an epidemiologist, Dr. Thompson is interested in determining the frequency with which a specified event occurs within a particular population at a certain instant or during a particular period. This measure is known as a rate. In epidemiologic practice, an attack rate is the most commonly used method of determining the extent or frequency with which a disease is experienced by a population of individuals. In this instance, Dr. Thompson is interested in knowing what percentage of the individuals who attended the July 4 celebration became ill. The attack rate is the number of individuals treated and/or had symptoms divided by the number of attending individuals. What is the attack rate of food poisoning among the group who attended the July 4 celebration?

105/150(100)= 70.0%

Rickettsia rickettsii is a gram-negative, obligate intracellular pathogen. Which of the following statements about the R. rickettsii life cycle is FALSE?

After entering a host, R. rickettsii multiplies to levels high enough to successfully invade cells and establish an infection.

Which of the following bacterial genera includes species that protect areas of the body such as the intestinal tract and the vagina from invasion by pathogens?

Lactobacillus

Which of the following findings are key to the cause of the outbreak? Select all that apply.

Large quantities of meat were prepared and kept warm for a long time before they were served. The sauce was prepared on an overcrowded steam table and, as a result, did not reach an appropriate temperature to kill any organisms.

Which of the following best explains why Tori developed a new series of symptoms?

The antibiotics that treated Tori's primary respiratory infection also removed some of her normal bacterial flora, resulting in an overgrowth of other organisms.

How is the dormant form of Rickettsia rickettsii activated?

The bacteria are activated after the tick feeds on a host for several hours.

Strains of Streptococcus pneumoniae can cause disease only when a capsule is present. Why is the presence of a capsule considered a virulence factor?

The capsule prevents the bacterium from being digested after endocytosis in the cells of the host.

The polymerization of actin filaments allows Listeria to form pseudopods extending from the host cell. How does this aid the bacteria during infection?

They are able to spread to neighboring cells sheltered from detection by the host immune system.

Which of the following is CORRECT about the prokaryotes known as deeply branching bacteria?

They are commonly found in acidic, anaerobic conditions.

An appropriately stained smear was prepared of a sputum specimen obtained from the sick woman on Lance's flight. Using oil-immersion magnification on your microscope, what would you observe that would aid in the diagnosis of tuberculosis?

acid-fast rods

What antifungal drug is commonly used to treat systemic mycoses of pathogenic fungi?

amphotericin B

What is the "gold standard" for treatment of histoplasmosis?

amphotericin B

MDR-TB is more problematic in a hospital than "regular" tuberculosis because MDR-TB is

antibiotic resistant

Some scientists want to study cellullar interactions in colonial organisms; they could use ___________ as a research organism.

colonial algae

The substance appears to be __________. Examine the image seen through the microscope and select the best answer.

fungi

A dikaryon differs from a diploid cell in that the dikaryon _____.

has two separate nuclei

What are dimorphic fungi?

have both a yeast and mold form

If the hyphae of a fungus are septate, this means they _____.

have crosswalls separating the cells

How did this couple become infected with C. jejuni?

ingestion of contaminated, raw milk

What was the source of the infection?

inhalation of spores from the bat guano

A characteristic symptom of necrotizing fasciitis is that the pain __________.

is disproportionate to the appearance of the infection

Most microbes that reside in the intestines are facultative or obligate anaerobes. Describe the growth of facultative anaerobes in the presence of and also in the absence of molecular oxygen.

Facultative anaerobes can grow without molecular oxygen, but grow faster in its presence.

Plasmodium reproduces by binary fission.

False

Wanda recently started a job at a local free women's health clinic. She took this job because she was raised in a family that struggled financially, so the free clinics were an important aspect of her childhood health care and she wants to give back to her community. Although the clinic sees women for a variety of issues, the most common visits are related to family planning and prenatal care. Because of this, Wanda is reading about sexually transmitted infections in order to be better at her job. From her school studies, Wanda is familiar with the infectious agent, symptoms, and treatment of many sexually transmitted infections, but she is particularly interested in the statistics from the local Health Department about STI rates in the area. When Wanda reads that C. trachomatis is the most common STI in the region, she decides to investigate the Chlamydia group of bacteria further. Which of the following are true for the Chlamydia group of bacteria? Select all that apply.

They are all intracellular parasites. They are all very small in size.

Which of the following is NOT a property of Lactobacilli?

They are members of the high G + C Gram-positive bacteria.

A mushroom is an example of _____, which is the reproductive organ of a mold.

a fruiting body

The information in the news report seems to match the symptoms and disease progression in rhinocerebral zygomycosis. Brenda tells herself that the incident is unrelated to her findings earlier today because the contaminated machine is for mixing custom ointments and it is highly unlikely that an ointment could transmit rhinocerebral zygomycosis. On one hand she is relieved, but on the other hand she keeps thinking about how many spores are produced by the fungi and how easily they spread. In the back of her mind is the niggling little idea that in her inspections she could easily have missed spores, if there was no actual fungal growth. She heads back to the room to see what other equipment is near the ointment mill and to check the logs for what other drugs are mixed in the area. Which of the following pieces of equipment could be used to make a product that would transmit Zygomycota spores via inhalation? Select the correct answer.

a nasal spray bottling machine

To diagnose meningitis due to Listeria infection, physicians will first examine a patient's ___.

cerebrospinal fluid

The symptoms that Shelly is experiencing result from the interactions between Streptococus pyogenes (a prokaryote) and the cells (eukaryotes) within Shelly's body. Although there are similarities between these two types of cells, there are also important differences. Drag each of the structures to the appropriate bin to indicate whether it is found in prokaryotes only, in eukaryotes only, or in both.

prokaryote only -capsule eukaryote only -golgi complex -rER -mitochondria -nucleus both -flagella -plasma membrane -ribosomes -cytoplasm

Athlete's foot is caused by a variety of different fungal infections. The presentation of a severe case would look much like the photograph here. The interdigital spaces and any moist areas of the foot are likely to be affected first. As the disease progresses, the nail and nail bed become affected. Once the nails are infected, the course of treatment must involve three different areas. First, the feet must be kept clean and dry. This includes allowing shoes to air dry for 24 hours between wearings, wearing shoes made of leather or other "breathable" materials, using antifungal powders inside the shoes, changing socks at least twice daily, wearing sandals whenever practical, washing the feet with soap twice daily, and applying an astringent. Additional precautions include always wearing shower shoes in public showers/locker rooms and not sharing towels or wearing another person's shoes to prevent contact with the fungus and reinfection. Second, an appropriate antifungal cream, such as clotrimazole, should be applied to clean, dry feet daily. This helps to kill the infection from the outside toward the inside of the body. Third, in advanced cases that involve the nail bed oral medications are necessary for at least 12 weeks and often up to 6 months (until the new nail is visible and free of fungal discoloration and texture). This kills the fungus from the inside of the skin toward the surface. What would be the most effective oral agent to use for treating the condition depicted in this case?

terbinafine tablets