Unit 3 Micro Exam
The word "antibiotic" means
"against life"
Why does Dr. Turner change Chloe's initial antimicrobial therapy? Which of the following are valid reasons why Chloe's antimicrobial therapy should be changed? Select all that apply.
- The isolate is confirmed to be Burkholderia cepacia. - Results of antimicrobial susceptibility testing were conflicting.
All of the following are used by bacteria to attach to host cells EXCEPT
A-B toxins
Which of the following organisms feeds on red blood cells?
Entamoeba histolytica
Which of the following is mismatched?
Epiglottitis -sore throat
Which of the following is mismatched?
Florey and Chain identification of Penicillium as the producer of penicillin
Which of the following statements about toxoplasmosis is FALSE?
It is a severe illness in adults.
The Hepatitis B vaccine is which type of vaccine?
Subunit vaccine
Which of the following is FALSE concerning Clostridium species?
Their main reservoir is rabbits.
What does a vaccine contain?
Weakened or killed pathogen or parts of a pathogen
Dental plaque is an example of
a biofilm.
Transient microbiota differ from normal microbiota in that transient microbiota
are present for a relatively short time.
Newborns' eyes are treated with an antibiotic
as a routine precaution.
Which of the following fungal infections results in a white, curdy discharge?
candidiasis
Which of the following is caused by an opportunistic pathogen?
candidiasis
"Rice water stools" are characteristic of
cholera.
Which of the following definitions is INCORRECT?
epidemic: a disease that is endemic across the world
More than half of our antibiotics are
produced by bacteria
Which of the following pairs is mismatched?
puerperal sepsis Staphylococcus aureus
A positive LE test and 10,000 CFU/ml in urine indicates
pyelonephritis.
Which of the following is diagnosed by detection of antibodies against the causative agent?
syphilis
Which of the following is treated with penicillin?
syphilis
Cats have been identified as an essential part of the life cycle for the protozoan that causes which disease?
toxoplasmosis
The greatest single cause of blindness in the world is
trachoma.
A patient has a skin ulcer from which a gram-negative bacillus is cultured. This patient has regional lymph nodes that are enlarged and filled with pockets of pus. He reports keeping pet rabbits. Which of the following is a possible diagnosis?
tularemia
Many bacterial infections of the lower digestive tract are treated with
water and electrolytes.
Consider the different mechanisms through which antibiotics inhibit microbial growth, and consider what changes in the microbe might enable it to resist the inhibitory effects of antibiotics. Select all of the statements that describe a mechanism that would enable a microorganism to resist the action of an antibiotic.
- Altered porins in the cell wall block passage of antibiotic through the cell wall. - A microbe develops a transport mechanism in the plasma membrane that rapidly pumps antibiotic out of the bacterial cell. - An enzyme that destroys the antibiotic is produced. - Target site is modified, so that an antibiotic is unable to bind to its target.
Which of the following choices correctly matches the class of antibiotic and its mode of action? Select all that apply.
- Aminoglycosides and tetracyclines are inhibitors of protein synthesis. - Sulfonamides inhibit the synthesis of essential metabolites.
Identify the statements below that accurately describe the mechanisms through which organisms acquire antibiotic resistance. Select all of the statements that accurately describe the origins and spread of antibiotic resistance.
- Antibiotic-resistance genes can be passed horizontally via transduction. - Antibiotic resistance is readily transmitted to the next generation during binary fission. - Mutations are the ultimate source of antibiotic-resistance genes. - Antibiotics select for those microbes that have developed resistance, increasing their frequency in the bacterial population. - Antibiotic-resistance genes can be passed from one bacterium to another by bacterial transformation. - Antibiotic-resistance genes can be passed horizontally via bacterial conjugation.
You carefully think over these results. You ultimately decide to drain the pus from the carbuncle and dress the wound. You instruct the boy and his family about proper wound care and decontamination to prevent the spread and recurrence of the infection. Why did you not prescribe antibiotics in this case?
- Antibiotics may increase opportunistic infections. - Using antibiotics can accelerate drug resistance in Staph. - Antibiotics will kill off beneficial bacteria. - Antibiotics have side effects.
Which of the following statements regarding antigenic shift are true? Select all that apply.
- Antigenic shift results in a major change in the genetic composition of the virus. - Little immunity to virus strains resulting from antigenic shift exists in the population. - Viral strains resulting from antigenic shift contain RNA segments from different species.
Which of the following conclusions are supported by the current research data? Select all that apply.
- Burkholderia cepacia complex appears to be very diverse in its habitat and distribution. - Genomovars III and II appear to be the most virulent or transmissible to humans. - It would appear that the environment may serve as a reservoir for acquiring Burkholderia cepacia complex strains.
What are some of the current challenges to production of the influenza vaccine? Select all that apply.
- In order to yield a vaccine, the virus must be produced in eggs. - The virus undergoes antigenic changes on a regular basis.
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? Select all that apply.
- Indirect FA will detect R. rickettsii-specific antibodies present in the patient's serum. - Indirect FA is more sensitive than direct immunofluorescent testing. - Indirect FA uses an antibody that reacts with any human antibody. - Indirect FA is rapid, sensitive, and specific.
Natural selection is a gradual, nonrandom process by which biological traits become more or less frequent within a population. Which of the following are necessary conditions for natural selection to occur within a population of Staphylococcus aureus?
- Individuals in the population vary from one another. - Some individuals in the population reproduce more than others. - Traits are hereditary. - Traits that permit an individual to survive at least until reproduction will increase in frequency over time.
Which of the following contribute to drug resistance in M. tuberculosis?
- Many individuals fail to complete their entire regimen of antibiotics. - Some physicians prescribe the wrong medication, the wrong dosage, or the wrong length of time for treating tuberculosis. - In many areas, tuberculosis antibiotics are unavailable or of poor quality.
The two most common STI organisms associated with PID in the United States are Chlamydia trachomatis and Neisseria gonorrhoeae. There are many similarities between these STIs. Which of the following statements comparing chlamydia and gonorrhea are true? Select all statements that are TRUE.
- Patients may be coinfected with both gonorrhea and chlamydia. - Chlamydia and gonorrhea can infect a patient and be transmitted without causing obvious symptoms. - Chlamydia is found more often in women, whereas gonorrhea is found more often in men.
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. - 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. - Histological observation indicates that morphological alteration and sloughing of epithelial cells occurs up to a maximum of 1000 units.
Which of the following findings are key to the cause of the outbreak? Select all that apply.
- The sauce was prepared on an overcrowded steam table and, as a result, did not reach an appropriate temperature to kill any organisms. - Large quantities of meat were prepared and kept warm for a long time before they were served.
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. Select all that apply.
- Without prompt treatment, RMSF can have a mortality rate as high as 20%. - 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.
Predict which of the following are reasonable outcomes of the cytokine storm during the 1918 flu pandemic. Select all that apply.
- an excessive inflammatory response leading to extensive tissue damage - increased fluid in the lungs and labored breathing
Predict which of the following would be outcomes of treatment with Tamiflu. Select all that apply.
- an increase in the ability of the immune system to combat the infection - a decrease in the release of viral particles from the cell - overall decrease in the replication rate of influenza
Chlamydia PID is just part of the overall spectrum of disease caused by Chlamydia organisms. Even though we now understand more about STIs and their complications, we are still exploring how the organisms "branch out" beyond just a single infection. Which of the following diseases have Chlamydia infection as an etiology? Select all diseases associated with Chlamydia.
- infertility - pneumonia - lymphogranuloma venereum (LGV) - inclusion conjunctivitis - trachoma - cervical cancer
Which of the following are symptoms of influenza infection? Select all that apply.
- muscle pain - fever - headache
Because Chloe is complaining of stomachache and is refusing food, Dr. Turner orders tests to evaluate Chloe for pancreatic insufficiency. Which of the following test results would indicate pancreatic insufficiency? Select all that apply.
- reduced pancreatic elastase levels - detection of fat in the feces, which indicates that fats are not being digested and appropriately absorbed in the intestine
Now that you have considered the evidence at hand, you should start to build a hypothesis about what disease your patient has. In the beginning of your diagnostic process you should try to think broadly and consider any and all reasonable possibilities. You can then narrow down these possibilities by performing diagnostics that can support or refute your hypothesis. Select all conditions that could reasonably apply to your patient.
- staphylococcal skin infection (folliculitis, impetigo, scalded skin syndrome, toxic shock syndrome) - streptococcal skin infection (necrotizing fasciitis, erysipelas) - acne
If Caleb's strain of M. tuberculosis is sensitive to antibiotic treatment, which of the following could be used to treat his infection? Select all that apply.
- streptomycin - isoniazid and ethambutol - rifampin
After reviewing your patient's medical history, you decide to list out the factors that you think will be most important to your diagnostic process. Review the following list and select the factors that you believe are most relevant to a diagnosis.
- the fact that more than one person had similar symptoms - the patient's symptoms - the fact that the bite did not respond to treatment with antibiotic ointment - the patient's activities before and during the infection
Chloe's mother wants to have another child. However, she is concerned that a second child might also have CF, so she encourages Chloe's stepfather to be tested. Tests reveal that he does NOT carry the CF gene. What is the chance that a second child born to Chloe's mother and stepfather will have CF?
0% chance of having CF
Arrange in the correct order the following pathologic events in cystic fibrosis lung disease.
1. CFTR defect results in production of dehydrated, thick mucus. 2. Thick mucus results in impaired ciliary clearance. 3. Bacteria become trapped in mucus, resulting in a chronic bacterial infection. 4. As a result of bacterial infection, a chronic neutrophilic inflammatory response ensues. 5. Inflammation results in bronchiectasis and fibrosis of lung bronchial walls.
The successful infection of a host, and subsequent spread to another, results from a specific sequence of events known as the replication cycle. Each of the statements below describes an important step in the replication cycle of influenza. Arrange the following statements in the order that best describes the sequence of events involved in the replication of influenza.
1. Hemagglutinin (HA) spikes attach to host cells 2. Influenza enters the host cell 3. Nucleic acid enters the host cytoplasm. 4. Influenza proteins are synthesized. 5. Influenza nucleic acid is packaged in capsid. 6. Influenza particles bud from the cell, releasing the virus into the surrounding environment
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.
1. Sporulation and lysis of vegetative cells result in teh release of CPE 2. CPE binds to claudin receptors of the tight junctions of intestinal epithelia. 3. Absorption of fluid and ions across the epithelia is inhibited. 4. Formation of the CPE-claudin complex results in active pore formation 5. Calcium ion influx results in activation of calpain 6. Cellular death and loss of epithelial layer of intestinal villi result in fluid secretion into lumen and diarrhea 7. Increased myoelectrical activity of intestine leads to severe cramping
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.
1. Tick bites transmit R. rickettsii into bloodstream 2. R. rickettsii travels throughout the body via the blood and lymph systems 3. R. rickettsii invades endothelial cells of blood vessels 4. R. rickettsii multiples within host cells 5. Blood begins to escape from vessels as a result of increased vascular permeability 6. Symptoms, such as a macular rash, develop
A patient comes in with a possible Chikungunya infection. Rank the following in order. Drag and drop the steps below in the appropriate order from left to right.
1. uninfected mosquito feeds on an infected person 2. Replication of the virus inside the vector 3. infected mosquito feedson uninfected person 4. patient has fever, headaches, and joint pain 5. treatment with supportive therapy
The minimal inhibitory concentration of antibiotic X in the table given is
10 μg/ml.
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%
The following data were obtained from a broth dilution test. as illustrated by the data shown, the minimal bactericidal concentration of antibiotic X is
15 μg/ml.
Which of the following antibiotics are used to treat fungal infections? 1. aminoglycosides 2. cephalosporins 3. griseofulvin 4. polyenes 5. bacitracin
3 and 4
Which compound would be the most useful to treat Herpes Virus?
Acyclovir
The Big Picture Activity mentioned that because no vaccine is available, prevention is the next method for keeping the number of infections to a minimum. One of the methods recommended by the CDC is to prevent infected individuals from receiving mosquito bites during the first week of their infection. How does this help prevent further spread of infection?
Additional bites would increase the chances of an uninfected vector acquiring the virus.
STI home test kits are still relatively new on the market. Given their newness, it is necessary to weigh the benefits and the risks to doing the tests at home. Place each statement below in the appropriate bin. Drag and drop the items into the appropriate bin.
Advantage: - increased treatment - anyone can purchase and use - improved communication Disadvantage: - kits can make mistakes - information leaks - increased costs
John mentioned that while in the Caribbean, he had been very careful to wear bug spray when outside and to use a mosquito net around the bed at night. Why were these protective measures not enough to keep him from being infected?
Aedes mosquitoes prefer to live inside buildings, are more resistant to bug spray, and feed during the day.
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.
Legionella is transmitted by
Airborne transmission.
The rate that bacteria develop antibiotic resistance at can be sped up by:
All of the above
To contract the Coronavirus, you first have to come into contact with it through..
All of the above
Pyelonephritis may result from
All of the answers are correct.
Which of the following can contribute to postoperative infections?
All of the answers are correct.
Which of the following causes opportunistic infections in AIDS patients?
All of the answers are correct.
Which of the following is NOT a cytopathic effect (CPE) of viruses?
All of the listed choices are possible cytopathic effects of viruses
Which of the following is NOT a predisposing factor of disease?
All of these are predisposing factors of disease.
What is the primary benefit of vaccination?
An immune response will occur quicker upon future exposure to the pathogen
Which of the following would be an example of an infection initiated via the parenteral route?
An individual contracts hepatitis B from an accidental stick with a contaminated needle.
Why does the physician start Caleb on the antibiotic azithromycin before laboratory results come back?
Antibiotic therapy is started with a broad-spectrum antibiotic because broad-spectrum antibiotics are effective against many gram-positive and many gram-negative bacteria.
Nicole is very upset after receiving news that her ex-boyfriend Paul had tested positive for syphilis and gonorrhea. She makes an appointment with her physician. Nicole receives her test results, which indicate that she is positive for syphilis, but not for gonorrhea. What treatment will her doctor most likely prescribe?
Antibiotics
Robert just returned home from the eye doctor. He was suffering from a red and painful eye, excessive tearing or discharge, and sensitivity to light. The doctor was concerned that Robert's eye infection may have come from his extended-wear contact lenses. Robert was given a prescription for antibiotics and was told to wear his glasses until the infection cleared. After completing the prescribed antibiotics, Robert's eye was still red, painful, and draining excessively. Why were the antibiotics prescribed for Robert not effective against the organism causing his eye infection?
Antibiotics are only effective against bacterial pathogens.
Which of the following statements is TRUE?
At least one member must benefit in a symbiotic relationship.
In which of the following North American locations would you expect to find the highest incidence of infection with Borrelia burgdorferi?
Atlantic coast
Which type of vaccine could possibly cause a person to develop the disease?
Attenuated live vaccine
What is the function of boosters?
Boosters are injections that are given periodically to maintain immunity.
A patient has a paroxysmal cough and mucus accumulation. What is the etiology of the symptoms?
Bordetella
Which one of the following causes a disease characterized by the catarrhal, paroxysmal, and
Bordetella pertussis
Which one of the following causes a disease characterized by the catarrhal, paroxysmal, and convalescent stages?
Bordetella pertussis
In what way are semisynthetic penicillins and natural penicillins alike?
Both are based on β-lactam
In what way are semisynthetic penicillins and natural penicillins alike?
Both are based on β-lactam.
The pathology of cepacia syndrome is often complex and due to multiple factors. All of the following factors may contribute to the development of cepacia syndrome EXCEPT which one?
Burkholderia cepacia produces an inducible beta-lactamase
A patient has pneumonia. Gram-negative rods are cultured on nutrient agar from a sputum sample. The etiology is
Burkholderia pseudomallei.
Microscopic examination of a patient's fecal culture shows spiral bacteria. The bacteria probably belong to the genus
Campylobacter jejuni.
A 35-year-old woman has a red, raised rash on the inside of her thighs. Gram-stained skin scrapings show large budding cells with pseudohyphae. The infection is caused by
Candida albicans
Thrush and vaginitis are caused by
Candida albicans.
How can capsules enable bacteria to evade the immune system?
Capsules block the complement biding sites on the surface of the pathogen.
Match each item related to the penetration or evasion of host defenses with its best description.
Capsules: This viscous outer covering found in certain microorganisms helps pathogens evade the host's defenses by impairing phagocytosis. Cell wall components: These structures contain substances that contribute to a pathogen's virulence; for example, M protein mediates microbial attachment to epithelial cells. Enzymes: These proteins contribute to a pathogen's virulence by, for example, forming and breaking down fibrin clots, breaking down connective proteins, and countering certain types of antibodies. Antigenic variation: This process allows pathogens to alter their surface antigens to avoid attack by antibodies produced by the immune system. Invasins: These microbial surface proteins rearrange the host cell's actin filaments, allowing pathogens to enter and move in and between cells.
What is meant by selective toxicity?
Chemotherapeutic agents should act against the pathogen and not the host.
One form of NGU is lymphogranuloma venereum caused by
Chlamydia trachomatis.
Microscopic examination of a lung biopsy shows spherules. What is the etiology of the symptoms?
Coccidioides
Which of the following is NOT an intracellular parasite?
Coccidioides
What is COVID-19 disease
Coronavirus disease 2019 (COVID-19) is a respiratory illness caused by a novel coronavirus that was first identified in 2019.
What is a coronavirus?
Coronaviruses are a large family of viruses that are known to cause illness ranging from the common cold to more severe diseases
The patient is suffocating because of the accumulation of dead tissue and fibrin in her throat. What is the etiology of the symptoms?
Corynebacterium
Which one of the following is an irregular, gram-positive rod?
Corynebacterium diphtheriae
During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.The etiologic agent of the disease in the situation is
Coxiella burnetii.
The following results were obtained from a disk-diffusion test for microbial susceptibility to antibiotics. Staphylococcus aureus was the test organism. In the table, the most effective antibiotic tested was
D. Largest zone of inhibition
Quinolones and fluoroquinolones act against what bacterial target?
DNA gyrase
Why does Dr. Bell start Caleb on HIV therapy in addition to the antibiotics used to treat the tuberculosis?
Dr. Bell prescribes Caleb HIV therapy because the virus is not affected by the antibiotics used to treat tuberculosis.
Which of the following is an example of the symbiotic relationship known as mutualism?
E. coli within the large intestine
There are numerous examples of microorganisms displaying each of the four major resistance mechanisms. In this activity, you are asked to identify the mechanism that each example best illustrates. Drag each item into the appropriate bin.
Enzymatic inactivation of the antibiotic: - Many strains of Neisseria gonorrhoeae are resistant to penicillin because of the production of β-lactamases Prevention of penetration to the target site within the microbe: - Resistance to tetracycline may result from modified pore proteins in the outer membrane that form a porin too small for the tetracycline to pass through. Alteration of the drug's target site: - Resistance to clindamycin develops when mutations in bacteria alter the ribosomal binding site to which clindamycin would normally bind. - MRSA (methicillin-resistant Staphylococcus aureus) is resistant to all β-lactam drugs because of a mutation in its penicillin-binding protein (PBP). Rapid efflux of the antibiotic: - Pseudomonas aeruginosa has membrane pumps that export a number of different antibiotics from its cells.
A patient exhibits hemorrhagic colitis and is treated via intravenous rehydration. The pathogen is a gram-negative rod. It is isolated and differentiated from related organisms based on its inability to ferment sorbitol. Which of the following is a likely diagnosis?
Escherichia coli gastroenteritis
Cystitis is most often caused by
Escherichia coli.
Most nosocomial infections of the urinary tract are caused by
Escherichia coli.
Pyelonephritis usually is caused by
Escherichia coli.
The most common cause of traveler's diarrhea is
Escherichia coli.
A microbe that enters the vagina would likely cause cystitis if left untreated.
False
Candida is a normal flora found in the majority (greater than 50%) of women.
False
Dental caries can also be referred to as periodontal disease.
False
EHEC is a major cause of diarrhea in developing countries and may result in the death of small children.
False
In a vaccine preparation, the term "attenuated" means that the agent does NOT replicate
False
In general, the LD50 for exotoxins is much greater than the LD50 for endotoxins.
False
Neonatal sepsis is most commonly caused by group A streptococci.
False
Reservoirs of infections are always animate objects.
False
Women and men typically have the same normal microbiota in their reproductive systems.
False
In the figure, when is the prevalence the highest?
February
As you can see from this activity, the immune system is very complex and is made of many components. In this section, place each immune component in the appropriate bin.
First line of defense: sebum (oil) sweat Second line of defense: fever NK cells Third line of defense: B lymphocytes T lymphocytes
Robert went from being fine to having a full-blown eye infection. Thinking about how his eye infection could have developed, rank the following in order from the first to the last step of this disease. Drag and drop the steps below in the appropriate order from left to right.
First step: - Fusarium cells attach to the eye - fungal mat and/or biofilm form(s) - inflammation of the cornea - eye becomes red, painful, and drains - antifungal therapywith natamycin Last step:
In this activity, you will identify the general mechanism of inhibition for the antimicrobial actions listed. Drag each item into the appropriate bin.
First: - Inhibiting synthesis of peptide cross-links - Inhibiting bonding of N-acetyl glucosamine to N-acetylmuramic acid - Inhibiting lipopolysaccharide synthesis - Inhibiting mycolic acid synthesis Second: Inhibiting fatty acid synthesis Third: Inhibiting DNA gyrase Interfering with DNA polymerase Fourth: Interfering with RNA polymerase Fifth: Interfering with activity of 30S ribosomal subunit Interfering with activity of 50S ribosomal subunit Interfering with attachment of tRNA to mRNA Interfering with peptide bond formation, catalyzed by the ribosome
Which compound would be the most useful to treat candidiasis?
Flucytosine
Which of the following statements is true regarding hand washing?
Frequent and proper hand washing should be routinely done by patients and by healthcare workers, both prior to and after interaction.
All of the following protect the skin and mucous membranes from infection EXCEPT
HCl
The patient is suffocating because of an inflamed epiglottis. What is the etiology of the symptoms?
Haemophilus
Which of the following bacterial pneumonias would you NOT treat with tetracycline?
Haemophilus influenzae pneumonia
Why are chemotherapeutic agents that work on the peptidoglycan cell wall of bacteria a good choice of drug?
Humans and other animal hosts lack peptidoglycan cell walls.
Which of the following enzymes breaks down the "glue" that holds cells together?
Hyaluronidase
__________ antibodies are found in mucosal secretions and help to protect the respiratory system from infection
IgA
__________ antibodies are found in mucosal secretions and help to protect the respiratory system from infection.
IgA
The at-home tests work similarly to pregnancy tests and are based on antigen-antibody reactions between the infectious agent and the patient's antibodies. Which class of antibody is most likely to give a result in the assay?
IgG
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.
Why is polymyxin only used on the skin?
It can also damage living human cell membranes, but the drug is safely used on the skin, where the outer layers of cells are dead.
Which of the following statements about pelvic inflammatory disease is FALSE?
It can be caused by T. pallidum
Which of the following statements about staphylococcal food poisoning is FALSE?
It can be prevented by heating foods to 50°C for 15 minutes.
How does the protozoan Trypanosoma evade detection by the immune system?
It can change the surface antigens frequently, preventing the immune system from tracking it.
Which organism in the table causes the most severe disease?
It cannot be determined from the information provided
Which of the following statements about drug resistance is FALSE?
It is found only in gram-negative bacteria.
In this activity, you will view data related to infectious doses for a specific microorganism and identify the best conclusion based on this data. Bacillus anthracis can cause infection via three different portals of entry. The ID50 of cutaneous anthrax is 10 to 50 endospores, whereas inhalation anthrax requires 10,000 to 20,000 endospores, and gastrointestinal anthrax requires 250,000 to 1,000,000 endospores. Which statement best describes a conclusion that can be drawn based on this information?
It is significantly easier to be infected with cutaneous anthrax as compared to other forms of anthrax.
Which of the following statements about puerperal sepsis is FALSE?
It is transmitted from mother to fetus.
Why is methicillin-resistant Staphylococcus aureus (MRSA) methicillin resistant?
It produces a modified version of the molecule that is targeted by the drug.
Which of the following statements about sepsis is FALSE?
It usually is caused by gram-negative bacteria.
As a child, Jamie suffered from rheumatic fever, which caused some major damage to one of her heart valves. She is OK, in general. However, she's been advised against getting body piercings, and her dentist gives her antibiotics before performing some dental procedures. What is the concern?
Jamie is more likely to develop subacute bacterial endocarditis.
Which organism in the table most easily causes an infection?
Legionella pneumophila Lowest ID50 means most likely to cause infection
In this activity, you will consider several scenarios and determine whether infection is likely or unlikely to occur. Reviewing the overall microbial mechanisms of pathogenicity (Figure 15.9), predict the ability of the pathogen to cause infection in each of the following scenarios.
Likely to cause infection: - A pathogen in quantities more than double its infectious dose is introduced at the appropriate portal of entry. - A pathogen that causes gastrointestinal infections is accidentally ingested in contaminated food. - A healthy individual inhales droplets from a person infected with a respiratory virus. - A population of microbes less than the infectious dose is introduced in a compromised human host. Not likely to cause infection: - A pathogen with multiple virulence factors is introduced in a healthy host, but in quantities far below its infectious dose. - A population of microbes greater than the infectious dose is introduced in a healthy individual, but these microbes are unable to adhere to host tissues. - A pathogen that causes urinary tract infections is accidentally ingested in contaminated water.
The adaptive immune response, or third line of defense, is activated when the first and second lines of defense do not succeed in containing an infection. It is adaptive because the cells in this part of the immune system are capable of responding to specific pathogens. Another important feature of the third line is the ability of these cells to create memory cells. Why are memory cells an important product of an immune response?
Memory cells allow subsequent immune responses against the same antigen to occur more strongly and more quickly.
When a person has previously been vaccinated against a viral pathogen, which cells are activated if that same pathogen re-enters the host's cells months or years later?
Memory cytotoxic T cells
Which of the following cause(s) ringworm?
Microsporum and Epidermophyton
The patient has scaling skin on his fingers. Conidiospores are seen in microscopic examination of skin scrapings. The etiology is
Microsporum.
What are leukocidins?
Molecules that are capable of destroying phagocytes
In this activity, you will classify portals of entry as mucous membrane, skin, or parenteral route. Sort each item based on which one of the following portals of entry it best represents: mucous membrane, skin, or parenteral route.
Mucous membrane: genitourinary tract gastrointestinal tract respiratory tract conjunctiva Skin: hair follicles conjunctiva Parenteral route: surgery injections deep wounds
Infection by which of the following results in the formation of Ghon complexes?
Mycobacterium tuberculosis
Which of the following is mismatched?
Mycobacterium whooping cough
Infection by which of the following is often confused with viral pneumonia?
Mycoplasma
Which one of the following produces small "fried-egg" colonies on medium containing horse serum and yeast extract?
Mycoplasma
Which of the following statements regarding tuberculosis is FALSE?
Nearly 1/3 of the world's population shows symptoms of tuberculosis.
Which one of the following does NOT cause nongonococcal urethritis?
Neisseria
Meningitis and gonorrhea are caused by
Neisseria species
Which of the following is NOT a complication of gonorrhea?
None of the answers are correct; all of these are potential complications of gonorrhea.
Nicole received her diagnosis at her physician's office. Which of the following procedures was most likely used by the physician to confirm her infection?
Nucleic Acid Amplification Testing (NAAT)
In this activity, you will view scenarios for the initiation of an infection and determine whether they relate to the number of invading microbes or adherence to the host tissue. Each of the following scenarios describes factors that influence infection at the portal of entry. For each scenario, determine whether the pathogen's ability to cause infection relates to the number of invading microbes or adherence to the host tissue.
Number of invading microbes: - For Vibrio cholerae, the infectious dose is 108 cells, but if stomach acid is neutralized with bicarbonate, this number decreases significantly. - For cutaneous anthrax, the infectious dose is 10 to 50 endospores, whereas for inhalation anthrax and gastrointestinal anthrax, the infectious doses are 10,000 to 20,000 and 250,000 to 1,000,000 endospores, respectively. Adherence to the host tissue: - Neisseria gonorrhoeae uses fimbriae to attach to cells in the genitourinary tract, eyes, and pharynx. - Staphylococcus aureus binds and infects skin by a mechanism that resembles viral attachment. - Treponema pallidum uses its tapered end as a hook to attach to host cells during a syphilis infection. - Enteropathogenic strains of Escherichia coli have fimbriae that bind to specific regions of the small intestine.
You would like to determine which species of Staphylococcus your patient is infected with. Which test will allow you to eliminate some possibilities?
One of the most important phenotypic features that can be used to differentiate among Staph species is their ability to produce coagulase , an enzyme that causes blood clot formation. Yes! You perform a coagulase test. Your results are shown here:
All of the following result from N. gonorrhoeae infection. Which one leads to the others?
Opa protein attaches to CD4+ T lymphocytes.
Which of the following statements concerning pathology, infection, and disease is true?
Pathology refers to the study of structural and functional changes that occur in the body as a result of a disease
Which of the following is included in GALT?
Peyer's patches
Which of the following is an opportunistic pathogen?
Pneumocystis
In this activity, you will identify portals of entry and exit found in a human host. Sort each item based on whether it represents a portal of entry, portal of exit, or both portal types.
Portal of entry only: None Portal of exit only: None Both portal of entry and portal of exit: skin mucous membrane parenteral route
Which statement regarding normal microbiota of the urinary and reproductive systems is true?
Pregnancy and menopause are associated with higher rates of urinary tract infections.
Which of the following is mismatched?
Q fever Rickettsia
Which of the following is mismatched?
Q fever — Rickettsia
Soil is a reservoir for all of the following EXCEPT
Q fever.
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
Which of the following is mismatched?
Salmonella endotoxin lyses red blood cells
Poultry products are a likely source of infection by
Salmonella enterica.
The patient has a papular rash. Microscopic examination of skin scrapings reveals small eight-legged animals. The etiology is
Sarcoptes.
Before you can treat you patient, there is a very important factor you must consider.
Selecting the best drug to treat Staphylococcus aureus infections can be difficult because some strains of the bacteria have developed drug resistance
Koch observed Bacillus anthracis multiplying in the blood of cattle. What is the condition specifically called when pathogens multiply in the blood?
Septicemia
In mice, the LD50 for staphylococcal enterotoxin is 1350 ng/kg, and the LD50 for Shiga toxin is 250 ng/kg. Which of the following statements is true?
Shiga toxin is more lethal than staphylococcal enterotoxin.
In this activity, you will match each factor that damages host cells with its description. Match each item related to damage to host cells with its description.
Siderophores: These proteins bind up iron obtained from the host cell's iron-transport proteins and transport this iron to bacteria through interactions with cell surface receptors. Direct damage: This occurs as a result of nutrient depletion, accumulation of waste products, pathogen entry and exit, and ruptured host cells Toxins: These poisonous substances cause most of the damage to host cells; they can be transported by the blood or lymph and may produce far-reaching effects. Lysogenic conversion: This results in a change in microbe characteristics due to the presence of prophage genes that confer new properties. Cytopathic effects: These describe the visible effects of viral infections that results in host cell damage.
Which of the following mutations would not result in antibiotic resistance?
Silent mutation
Which of the following characteristics of a catheter should be considered, to help minimize the spread of nosocomial infections?
Single-use
What is the public health practice that prevents sick people from coming into contact with healthy people in order to reduce opportunities for disease transmission?
Social Distancing
A child presents with large red patches of skin. The top layers are peeling off. Because the parents report that the child hasn't been burned, you suspect that the lesions are due to infection with __________.
Staphylococcus aureus
John went to a picnic. He took home some leftover chicken and rice, heated it on the stove, ate it, and got sick two hours later. John thought the heating made his food safe because it would have killed any bacteria present. He didn't know that __________ produces a heat-stable toxin.
Staphylococcus aureus
The patient has vesicles and scabs over her forehead. Microscopic examination of skin scrapings shows gram-positive cocci in clusters. The etiology is
Staphylococcus aureus
These results support the idea that your patient's infection was caused by ______.
Staphylococcus aureus
Which of the following virulence factors would be found in Staphylococcus aureus?
Staphylokinase
Which of the following bacterial infections CANNOT be transmitted by dog or cat bites?
Streptobacillus
All of the following are normal microbiota of the skin EXCEPT
Streptococcus
Which one of the following causes a disease characterized by a red rash?
Streptococcus
Which of the following organisms would MOST likely be sensitive to natural penicillin?
Streptococcus pyogenes
To date, most of our natural antibiotics have been found to be produced by members of what genus?
Streptomyces
You take a sample of pus from your patient's abscess for analysis. Results from Gram-staining are shown here: What does this result show?
The Gram stain shows the presence of ______.: gram-positive, spherical bacteria
A patient who presents with red throat and tonsils can be diagnosed as having
The answer cannot be determined based on the information provided.
What is meant when a bacterium is said to become "resistant" to an antibiotic?
The bacterium is neither killed nor inhibited by the antibiotic.
Based on the information from Part B, the causative agent of Robert's eye infection is most likely the fungus Fusarium. Some species of Fusarium are known to produce biofilms. Which of the following is NOT a way in which the biofilm helps in the fungal pathogenesis involved in keratitis?
The biofilm allows for the breakdown of cellulose by producing the enzyme cellulase.
How does a capsule help certain bacteria evade detection by the immune system?
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.
Emergence of infectious diseases can be attributed to all of the following EXCEPT
The emergence of infectious diseases can be attributed to all of these
Which of the following statements about salmonellosis is FALSE?
The mortality rate is high.
An individual presents with a pinkish-red rash and a red sore throat. Gram-positive cocci are cultured from a throat swab. The cocci are growing in chains. Which of the following is the most likely conclusion?
The patient has scarlet fever.
Which of the following statements about nosocomial infections is FALSE?
The patient was infected before hospitalization.
A patient shows the presence of antibodies against diphtheria toxin. Which of the following statements is FALSE?
The patient was near someone who had the disease.
Which of the following statements about the development of infectious diseases is correct?
The period of convalescence is the time during which the person regains health and fully recovers (back to the pre-disease state).
Which of the following statements concerning mumps virus infection is FALSE?
The testes can become inflamed about 2 to 3 weeks after the onset of symptoms.
Which statement regarding normal microbiota of the human respiratory system is FALSE?
The upper respiratory tract is mostly sterile.
There are a large number of antibiotics that inhibit protein synthesis at 70S ribosomes found in bacterial cells but do not interfere with protein synthesis at the 80S ribosomes found in eukaryotic cells. Some of these antibiotics bind to the smaller ribosomal subunit and interfere with the reading of the mRNA code, whereas others bind to the larger ribosomal subunit and inhibit the formation of peptide bonds. Unfortunately, some of the antibiotics that inhibit protein synthesis in bacteria exhibit some toxicity to the eukaryotic host cells as well. What is the most likely reason for this toxicity to the host cell?
These antibiotics interfere with protein synthesis within eukaryotic mitochondria.
What is the hallmark of a conjugated vaccine?
These vaccines contain weakly antigenic elements plus a more potent antigenic protein.
How are immune cells able to detect foreign pathogens?
They are able to detect structures on the surfaces of foreign cells that are not found in the host
Which of the following is NOT an advantage of using live attenuated vaccines?
They are usually safer than other types of vaccines.
How do fibrinolysins enhance a pathogen's virulence?
They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.
In which of the following respects is measles similar to German measles (rubella)?
They can be controlled by vaccination
Broad spectrum antibiotics are bad because:
They can increase the rate of development of antibiotic resistance
Which of the following statements about group B streptococci is FALSE?
They cause strep throat.
How do superantigens enable pathogens to hide from the immune system if they actually stimulate the immune system?
They cause the immune system to produce an exaggerated response, distracting it from the actual pathogen
How can surgeons help to limit nosocomial infections?
They should perform surgeries and invasive procedures only when absolutely necessary.
What is the role of epidemiology?
To learn how to treat and prevent various diseases.
Which of the following statements about mycoplasmal pneumonia is TRUE?
Treatment is tetracyclines.
Nicole knew that these were both sexually transmitted infections caused by bacteria. Which of the following is correct regarding the causative agents for these diseases?
Treponema pallidum causes syphilis, while Neisseria gonorrhoeae causes gonorrhea.
Which of the following organisms is likely to be transmitted via undercooked pork and horse?
Trichinella spiralis
A host is not considered diseased until an infection changes one's state of health.
True
An antibiotic that attacks the LPS layer would be expected to have a narrow spectrum of activity.
True
An outbreak of viral gastroenteritis occurs in a pediatrics ward. Rotavirus is the most likely causative agent.
True
Anatomically, women have more portals of entry in the reproductive system compared to men.
True
Both normal and transient flora can become opportunistic pathogens.
True
Ergot and aflatoxin are toxins sometimes found in grains contaminated with fungi.
True
H. pylori is able to survive the acidic environment of the stomach as a result of adaptations that allow it to increase the pH of the immediate environment.
True
Infections with some viruses may induce chromosomal changes that alter the growth properties of host cells.
True
Microorganisms that are members of the normal microbiota are also known to cause disease.
True
The most common causative agent of bacterial pneumonia is Streptococcus pneumoniae.
True
The symptoms of diphtheria are due to an exotoxin that blocks proteins synthesis in host cells.
True
The varicella-zoster virus is the causative agent of chickenpox and shingles.
True
Which of the following microorganisms actually grows inside the macrophage?
Tuberculosis bacterium
Which of the following does NOT constitute an advantage of using two antibiotics together?
Two are always twice as effective as one.
Which of the following organisms is likely to be transmitted via contaminated shrimp?
Vibrio parahaemolyticus
Cytopathic effects are changes in host cells due to infections by
Viral
Why is it difficult to find good chemotherapeutic agents against viruses?
Viruses depend on the host cell's machinery, so it is hard to find a viral target that would leave the host cell unaffected.
Which of the following is NOT caused by infection of the upper respiratory tract?
Whooping Cough
A driving force of this sort of evolution is natural selection , which is sometimes colloquially referred to as the "survival of the fittest.
Yes! Natural selection is a driving force in the evolution of antibiotic resistance.
Assume that your lab partner swabs the side of his face and uses the swab to inoculate a nutrient agar plate. The next day, he performs a Gram stain on the colonies. They are gram-positive cocci. You advise him that he should next look for
a coagulase reaction
Our patient needs antibiotics to overcome this infection and prevent any further complications. Which of the following would be the best choice?
a combination therapy of cephalosporin-class AND macrolide-class.
John's physician said that he might be suffering from Chikungunya fever, an emerging disease that once was limited to Asia, Africa, and Europe, but is now making appearances in the Caribbean and the United States. How did John most likely get infected?
a mosquito bite
The bacteria appear to be in clusters, as opposed to chains. This suggests that your patient has ______.
a staphylococcal infection
What is the receptor for COVID-19
ace2
Buruli ulcer is caused by
acid-fast bacteria.
Staphylococcus aureus is responsible for all of the following EXCEPT
acne.
A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which treatment is appropriate?
acyclovir
Which of the following is used to treat shingles?
acyclovir
The fimbriae of Neisseria gonorrhea and enteropathogenic E. coli are examples of
adhesins and ligands.
Microbial resistance to drugs is acquired through
all of these
Which of the following antimicrobial agents is recommended for use against fungal infections?
amphotericin B
The yeast Candida albicans does not normally cause disease because of
antagonistic bacteria.
A compound synthesized by bacteria of fungi that destroys or inhibits the growth of other microbes is a/an
antibiotic
All of the following are generally used in vaccines EXCEPT
antibodies
All of the following are generally used in vaccines EXCEPT
antibodies.
Toxoid vaccines, such as the vaccines against diphtheria and tetanus, elicit a(n)
antibody response against these bacterial toxins.
Symptoms of disease differ from signs of disease in that symptoms
are changes felt by the patient.
What type of vaccine is the live, weakened measles virus?
attenuated whole-agent vaccine
Live weakened polio virus can be used directly in a(n)
attenuated whole-agent vaccine.
R-plasmids are most likely acquired via
bacterial conjugation.
All of the following can lead to a positive tuberculin skin test EXCEPT
being near someone with tuberculosis.
When the antibiotics failed to work against Robert's infection, the doctor was concerned that it might be caused by a fungal pathogen. The lab technician collected a sample from the pair of contacts he was wearing when he first started having symptoms, as well as the cleaning solution that he was using. The lab technician plated the samples on Sabaroud-Dextrose agar and incubated it for 5 days at 26 degrees C. After growth appeared on the agar, a microscope slide was made, stained with Lactophenol Cotton Blue, and observed. Which of the following would the lab technician most likely see?
blue filaments and conidiospores
In which of the following patterns of disease does the patient experience no signs or symptoms?
both incubation and convalescence
How do antifungal drugs such as miconazole and amphotericin B function?
by disrupting the plasma membrane
The common cold __________.
can result from deposition of a single rhinovirus on the nasal mucosa
Vaginal itching and cheesy discharge are symptoms of
candidiasis.
Which of the following does NOT contribute to the symptoms of a fungal disease?
cell walls
Genes for beta-lactamase are present in Burkholderia cepacia but are not normally expressed unless they are induced. Exposure to which of the following agents most likely induced the expression of beta-lactamase resistance in Burkholderia cepacia? (Select the one best answer.)
cephalexin
A patient has pus-filled vesicles and scabs on her face, throat, and lower back. She most likely has
chickenpox.
The physician performs a pelvic exam, which reveals the presence of an abnormal thin, watery vaginal discharge and inflammation of the cervix. The physician then palpates the abdomen (examines by touch and pressure) and finds that the uterus, fallopian tubes, and ovaries are enlarged and tender. The physician takes a swab sample of the cervix and sends it to the laboratory to determine the causal organism. Light microscopy and simple staining of the sample in the lab reveal an organism with a very unique life cycle. The organism is classified as gram-negative, but it stains very poorly compared to other classic gram-negative STI pathogens. The stain shows both a nonreplicating, extracellular infectious elementary body and a replicating, noninfectious reticulate body inside mucosal cells from the cervical epithelium swab. Based on the symptoms and these new laboratory findings, which of the following would be the most likely diagnosis for the patient?
chlamydia
Which of the following diseases is NOT correctly matched to its reservoir?
coccidioidomycosis air
The lower respiratory tract is protected by all of the following EXCEPT
competition with the normal flora of the lungs.
Haemophilus capsule polysaccharide plus diphtheria toxoid is a(n)
conjugated vaccine
Inflammation of the thin clear membrane lining the eyelid and eye is properly termed
conjunctivitis
Epidemics related to bacterial infection of the digestive system are typically caused by
contaminated food and water.
The most common mode of HAV transmission is
contamination of food during preparation.
What do we call a person who panics and buys a lot of stuff because of the coronavirus?
covidiot
In humans, beef tapeworm infestations are acquired by ingesting
cysticerci of Taenia saginata in undercooked meat.
Staphylococcus saprophyticus causes
cystitis.
the figure shows the incidence of influenza during a typical year. Which letter on the graph indicates the endemic level?
d
the table shows the ID50 for Staphylococcus aureus in wounds with and without the administration of ampicillin before surgery. Based on the data, the administration of ampicillin before surgery
decreases the risk of staphylococcal infection.
In cystic fibrosis, a defective gene and its protein product lead to the production of thick and dehydrated mucus because of __________.
defective secretion of chloride ions and excess absorption of sodium
A patient complains of fever, severe muscle and joint pain, and a rash. The patient reports returning from a Caribbean vacation one week ago. Which of the following do you suspect?
dengue
The following data were obtained from a broth dilution test: Bacteria from the 0.25 μg/ml tube were transferred to new growth media containing antibiotic X with the following results: The data in the table show that these bacteria
developed resistance to antibiotics.
You note that the body temperature of one of your patients is starting to increase. As a result, you can infer that all of the following may be occurring in this patient EXCEPT __________.
dilation of blood vessels
Which of the following requires treatment with both antibiotics and antitoxins?
diphtheria
Antimicrobial peptides (AMPs) frequently work by
disrupting the plasma membrane.
The most common reservoir for leptospirosis within the United States is
domestic dogs.
The following choices list several types of diseases, along with factors that may contribute to their emergence. Which disease and associated factor do NOT match?
emergence of avian influenza A (H5N1); use of antibiotics
Malaria is an infectious disease caused by infection with a protozoan. In certain tropical regions, malaria is constantly present. We would say that malaria is a(n) __________ disease in these regions
endemic
The symptoms of gas gangrene are due to all of the following EXCEPT
endocarditis
Epstein-Barr virus has been implicated in all of the following EXCEPT
endocarditis.
The graph in the figure shows the incidence of polio in the United States. The period between 1945 and 1955 indicates a(n)
epidemic level.
Members of the group A streptococci (GAS) cause all of the following EXCEPT
epiglottitis
Which of the following would be selective against the tubercle bacillus?
ethambutol — inhibits mycolic acid synthesis
In the 1940s, penicillin began to be widely used to treat a variety of bacterial infections. At that time, penicillin-resistant strains of S. aureus were virtually unknown. Twenty years later, 80% of hospital-acquired S. aureus were penicillin-resistant, leading to the introduction of methicillin in 1961 to combat penicillin-resistant strains. Within one year, doctors began to encounter methicillin-resistant strains of S. aureus. Since the development of methicillin-resistance, strains of S. aureus have become resistant to beta-lactam drugs (including all the penicillins), as well as some cephalosporins, leaving vancomycin (typically a "drug of last resort") as the favored treatment for antibiotic-resistant Staph infection.In the late 1990s, vancomycin-resistant strains of Staph began to appear. Around that time, oxazolidinones also became available, and linezolid, also a drug of last resort, was introduced as a treatment for S. aureus. Linezolid-resistant strains of Staph were subsequently reported in 2003.The development of multi-drug resistance in Staphylococcus aureus is a classic example of ______.
evolution
Clostridium difficile-associated diarrhea is usually preceded by
extended use of antibiotics.
All of the following are used as first-line drugs for treating tuberculosis EXCEPT
fluoroquinolones.
Sulfanilamides interfere with __________.
folic acid synthesis in bacteria
A drug that inhibits mitosis, such as griseofulvin, would be more effective against
fungi
A drug that inhibits mitosis, such as griseofulvin, would be more effective against
fungi.
A vaccine to provide active immunity to HBV is prepared from
genetically modified yeast.
A pelvic examination of a 23-year-old woman showed vesicles and ulcerated lesions on her labia. Cultures were negative for Neisseria and Chlamydia; the VDRL test was negative. Which of the following is probable?
genital herpes
The pH of the adult vagina is acidic due to the conversion of ________ to ________ by bacteria.
glycogen; lactic acid
The most common reportable disease in the United States is
gonorrhea.
Which one of the following does NOT contribute to the incidence of nosocomial infections?
gram-negative cell walls
If penicillin G is chosen as the best treatment for a given infection, what microorganisms are most likely the cause?
gram-positive bacteria
All of the following are characteristic of Pseudomonas aeruginosa EXCEPT
gram-positive cell wall.
All of the following are examples of entry via the parenteral route EXCEPT
hair follicle.
Vaccines can be used to protect at-risk individuals from all of the following liver diseases EXCEPT __________.
hepatitis C
All of the following are causative agents of conjunctivitis EXCEPT
herpes simplex
If a prodromal period exists for a certain disease, it should occur prior to
illness.
Which of the following causes of infertility may result from formation of scar tissue in the uterine tube?
inability of fertilized eggs to reach the uterus
The influenza vaccine is an example of a(n)
inactivated killed vaccine.
Dead Bordetella pertussis can be used in a(n)
inactivated whole-agent vaccine.
Julie is preparing vegetables for dinner and accidentally cuts her finger. She washes it with soap and water before covering it with a bandage. A short while later, Julie notices that her finger is red, swollen, warm to the touch, and very painful. Which of the following describes the process going on in Julie's finger?
inflammation
Which of the following methods of action would be bacteriostatic?
inhibition of protein synthesis
Innate immunity
is nonspecific and present at birth.
A urine sample collected directly from the urinary bladder
is sterile.
In the presence of penicillin, a cell dies because
it undergoes lysis.
Which of the following is directly involved in the initiation of dental caries?
lactic acid
A disease in which the causative agent remains inactive for a time before producing symptoms is referred to as
latent.
Focal infections initially start out as
local infections.
Which of the following is caused by Chlamydia?
lymphogranuloma venereum
Which of the following antibiotics does NOT interfere with cell wall synthesis?
macrolides
A 62-year-old man was hospitalized with an eight-day history of fever, chills, sweats, and vomiting. His temperature on admission was 40°C (104°F). A routine peripheral blood smear revealed ring-shaped bodies in the RBCs. What treatment would you prescribe?
mefloquine
All of the following are characteristic of the Group A beta-hemolytic streptococci EXCEPT
methicillin resistance.
The major significance of Robert Koch's work is that
microorganisms cause disease.
Following a county fair, 160 persons complained of gastrointestinal symptoms. Symptoms included diarrhea (84 percent), abdominal cramps (96 percent), nausea (84 percent), vomiting (82 percent), body aches (50 percent), fever (60 percent; median body temperature = 38.3°C); median duration of illness 6 days (range 10 hr to 13 days).In the situation, fecal samples were found to be negative when cultured. The next step in diagnosing the cause of illness would be
microscopic examination of feces for oocysts.
Scabies is a skin disease caused by a
mite.
Which of the following symptoms is LEAST characteristic of Clostridium perfringens food poisoning?
moderate vomiting and fever
Which non-specific defense mechanism is mismatched with its associated body structure or body fluid?
mucociliary escalator intestines
Polio is transmitted by ingestion of water contaminated with feces containing polio virus. What portal of entry does polio virus use?
mucous membranes only
Aflatoxin is a(n) ________ associated with ingestion of contaminated ________.
mycotoxin; peanuts
Since you have considered how bacteria evolve antibiotic resistance, you want to be very careful about what medicine you treat your patient's infection with. Although there is a fairly good chance that if you treat your patient with linezolid (a powerful antibiotic of last resort), his infection will improve, you also know that unnecessary antibiotic use can perpetuate the evolution of drug resistance. You decide to use the Kirby-Bauer test to assess the sensitivity of the strain of Staphylococcus aureus affecting your patient. Your results are shown below:P= penicillin, M= methicillin, E= erythromycin, V= vancomycin, X = trimethoprim sulfamethoxazole Given the above results, is it safe to say your patient has a MRSA infection?
no
Pseudomonas bacteria colonized the bile duct of a patient following his liver transplant surgery. This is an example of a
nosocomial infection.
A DNA plasmid encoding a protein antigen from West Nile virus is injected into muscle cells of a horse. This is an example of a(n)
nucleic acid vaccine
Which disease or microbe is NOT transmitted across the placenta to the unborn fetus?
ophthalmia neonatorum
Which of the following is not a common characteristic used in the selection of an antimicrobial drug?
penetration of the blood-brain barrier
As mentioned previously, the second line of defense is activated when the first line of defense fails. In Part A, you identified one of these defenses as inflammation, which occurs when the body responds to a foreign antigen and increases fluid accumulation in a specific area. An added benefit of this excess fluid is that it also brings immune cells to the area to aid clearance of foreign antigens. In Julie's situation, that added fluid would bring immune cells to prevent any microbial infections that could be caused if microbes were introduced when she cut her finger. Which of the following cell types is NOT part of the second line of defense?
plasma cells
A patient has fever, difficulty breathing, chest pains, fluid in the alveoli, and a positive tuberculin skin test. Gram-positive cocci are isolated from the sputum. The patient most likely has
pneumococcal pneumonia.
Which of the following antibiotics is recommended for use against gram-negative bacteria?
polymyxin
The antibiotic chloramphenicol binds to the 50S subunit of the ribosome, as shown in the figure. The effect is to
prevent peptide bond formation in prokaryotes.
The use of a drug to prevent a person at risk of an imminent infection is called
prophylaxis
A patient presents with a fever and flank pain. Microscopic analysis of the urine reveals bacteria at a concentration above 10,000 colony-forming units (CFUs) per milliliter. You perform a leukocyte esterase (LE) test, and it is positive. What is the diagnosis?
pyelonephritis
All of the following are protective factors of the skin and its secretions EXCEPT
pyocyanin production.
Which of the following is responsible for epidemics of respiratory disease in infants?
respiratory syncytial virus
Acute gastroenteritis that occurs after an incubation period of two to three days and commonly affects children is probably caused by
rotavirus.
Which of the following types of infection can result in infertility?
salpingitis
Exfoliative toxin is responsible for
scalded skin syndrome.
Which of the following is NOT controlled by a mosquito eradication program?
schistosomiasis
Which of the following definitions is INCORRECT?
secondary infection: a long-lasting illness
Treating fungal infections can be challenging. Fungi are classified as eukaryotic organisms, the same as their human host. The idea that antimicrobial drugs should only affect the microbe without harming the host is an important principle in microbiology. It is referred to as the principle of __________.
selective toxicity
Which of the following is classified as a latent disease?
shingles
The health of the patient
should be the primary concern of the healthcare worker.
Inflammation is part of the second line of defense that is activated when the first line of defense is breached. Julie's first-line defenses were damaged when her injury occurred. Which of the following represents the first line of defense?
skin and mucous membranes
Which of the following is/are associated with secondary stage syphilis?
skin rashes of varying appearance
Bacteria present in the __________ can be phagocytosed by Paneth cells.
small intestine
Most of the normal microbiota of the digestive system are found in the
small intestine and large intestine.
Thorough cooking of food will prevent all of the following EXCEPT
staphylococcal food poisoning.
Bacteria that cause periodontal disease have adhesins for receptors on streptococci that colonize on teeth. This indicates that
streptococcal colonization is necessary for periodontal disease.
Measles viruses are capable of inactivating host defenses by
suppressing the immune system
The antimicrobial drugs with the broadest spectrum of activity are
tetracyclines.
What part of the United States is endemic for RMSF?
the Appalachian region (North Carolina, Kentucky)
Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because
the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.
The ID50 is
the dose that will cause an infection in 50 percent of the test population.
When a patient is treated with antibiotics, __________.
the drug will kill or inhibit the growth of all of the sensitive bacterial cells
Which of the following is greater?
the number of reported cases of gonorrhea last year
Human-to-human transmission of plague is usually by
the respiratory route.
Which of the following is NOT an antimicrobial feature of the urinary system?
the use of the urethra for seminal fluid in women
Protozoan and helminthic diseases are difficult to treat because
their cells are structurally and functionally similar to human cells.
Normal microbiota provide protection from infection in each of the following ways EXCEPT
they produce lysozyme.
If a patient notices a healthcare worker not following suggested precautions,
they should immediately bring it to the attention of the healthcare worker.
Symptoms of protozoan and helminthic diseases are due to
tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.
Which of the following is NOT a cytopathic effect of viruses?
toxin production
Inactivated tetanus toxin is a(n)
toxoid vaccine.
You advise your pregnant friend to not adopt a new kitten from her neighbor because she could contract
toxoplasmosis.
The process of acquiring antibiotic resistance by means of bacteriophage activity is called
transduction.
Which of the following is evidence that the arthritis afflicting children in Lyme, Connecticut, was due to bacterial infection?
treatable with penicillin
All of the following infections can result from drinking contaminated water EXCEPT
trichinellosis
Which of the following is NOT typically treated with penicillin?
tularemia
In which of the following diseases can gender be considered a viable predisposing factor?
urinary tract infections
The rise in herd immunity amongst a population can be directly attributed to
vaccinations.
Certain traits that allow pathogens to create infection and cause disease are termed
virulence factors.
Now that we have looked at ways to prevent breeding in mosquitos, another possible prevention is to limit the vector geographically, but recent climate changes have led to changes in location where the mosquito can now be found. Which of the following climate change scenarios has allowed for this increase in vector habitat?
warmer temperatures in northern regions with increased rainfall
As a health care worker, you are keenly aware of how important it is to avoid harming patients. You worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the most important thing you can do to avoid this?
wash my hands before interacting with any patient
Epidemiology is defined as the study of
where and when a disease occurs, and how it is transmitted.
Which of the following is NOT caused by infection of the upper respiratory tract?
whooping cough
The primary victims of the influenza pandemic of 1918-1919 were
young adults.
