Exam 3 Flashcards
Which is NOT a property of the keystone pathogen for periodontitis?
> C: becomes the main species present in disease sites
Which bacterium is considered the keystone pathogen for periodontitis?
> E: Porphyromonas gingivalis
Which disease has oral manifestations that include gummas?
> A: syphilis
Which Streptococcal virulence factor is correlated with the progression of infective endocarditis?
PAAF
5 Which of the following is characteristic of Ludwig’s angina?
> D: infection is polymicrobial (multiple species)
6 How do mucins act as antibacterial agents? 1/1
> E: mucins aggregate and clear oral bacteria via lectin-like interactions
8 Aggregatibacter actinomycetemcomitans is very typically associated with which oral disease? 1/1
> D: aggressive periodontitis
What is one of the types of oral bacteria strongly associated with acute necrotizing ulceratize gingivitis? Answer:
Answer 1: Fusobacterium nucleatum
What is a property characteristic of cariogenic bacteria (versus noncariogenic bacteria)?
> C: presence of acid stress response proteins
Name a bacterium that is a common late colonizer of dental plaque when oxygen is depleted, especially between teeth?
Prevotella
What is true of dental plaque?
Sugar consumption causes increased levels of streptococcus mutans in plaque
What bacterial gene is used in current methods for classifying bacteria, including identifying new species?
16s RNA
Which property of bacteria in a dental biofilm is associated with decreasing the risk of dental caries?
> E: upregulation of ammonia production from arginine and urea
What bacterium lacks peptidoglycan and is the agent of the most sexually transmitted infections, characterized by mucopurulent discharges?
> C: Chlamydia trachomatis
Which organism is an obligate intracellular pathogen?
> A: Chlamydia trachomatis
17 Which form of Chlamydia replicates within a host cell?
Answer 1: reticulate body
: 18 Bacteria of which genus are transmitted to humans by bites of infected ticks? 1/1
Rickettsia
What is a symptom of late stage, chronic disease associate with Borrelia burgdorferi?
Arthritis
20 What is uniquely associated with congenital syphilis?
> E: mulberry molars
Name a bacterium that may be detectable by an acid-fast staining test of a sputum smear. Answer: __1__
Answer 1: Mycobacterium tuberculosis
Which of the following is true for Mycobacterium tuberculosis?
> C: the bacterium exhibits a very slow growth rate (doubling time of 1 day)
23 What is a property of the bacterial agent of Legionnaires’ disease?
> D: lives in amoeba in water sources within ventilation systems
Name a bacterium that survives in alveolar macrophages. Answer: __1__
Answer 1: Mycobacterium tuberculosis
What type of virulence factor of Haemophilus influenzae serotype b is specifically correlated with the ability of these bacteria to cause systemic infections?
Capsule B
This Gram-negative coccobacillus is transmitted zoonotically via fleas and eventually infects lymph nodes, producing characteristic swellings called “bubos.”
Answer 1: Yersenia pestis
27 Which of the following is true about Bacillus anthracis?
> B: produces a metallo-protease called lethal factor
Which Clostridium species is part of the normal human bacterial flora? Answer: __1__
C. difficle
29 Botulism results in 1/1
> E: flaccid muscle paralysis due to blocking release of the neurotransmitter acetylcholine
These gram positive rods establish themselves in the throat and kill cells by expressing a toxin that ADP- ribosylates elongation factor 2, causing inhibition of cellular translation.
> C: Corynebacterium diphtheriae
What is a property of the dissaccharide-tetrapeptide component of bacterial peptidoglycan that is the tracheal cytotoxin of Bordetella pertussis?
> B: it is shed from bacterial cells instead of being absorbed and recycled
32 The ability of Pseudomonas aeruginosa to produce a biofilm is dependent on 1/1
> B: alginate production
33 What pathogen resides in the stomach and induces the host to secrete urea through the mucosal epithelium?
Answer 1: Helicobacter pylori
Which enteric bacterium is acquired as a zoonotic infection, often from undercooked chicken, and causes a mild, self-limiting gastroenteritis?
> E: Campylobacter jejune
What is a property of cholera toxin and the system for spreading the genes encoding it?
> D: the toxin genes are encoded in a phage genome
Which of the following is true about cholera?
> B: supportive rehydration therapy is the main method used for treatment
Which enteric bacterium can invade M cells in the gut, survive in macrophages, and eventually infect many different organs in the body?
> A: Salmonella enterica serovar typhi
L I 38 Most cases of cytitis (bladder infections) are caused by which bacterial genus? 1/1
> A: Escherichia
L I 39 What is the effect of shiga toxin on the host? 1/1
> C: removal of a specific adenine base from 28S rRNA
Hemolytic uremic syndrome is a complication of infection by which organism?
> B: Escherichia coli O157:H7
Which programmed alteration of bacterial cell-surface protein expression is due to recombination of silent gene loci into the expressed gene locus for the protein?
> A: antigenic variation
Which of the following is the mostly likely characteristic of Campylobacter jejune?
> C: acquired as a zoonotic infection, often from undercooked chicken, and causes a mild, self-limiting gastroenteritis
To what surface feature of enteric bacteria does the term H-antigen refer?
flagella
What is not a property associated with Salmonella enterica serovar typhi?
> C: produces a cholera-like toxin
Which bacterium produces the vast majority (70-90%) of urinary tract infections (bladder infections, for example)?
> B: Escherichia coli
Bacteroides fragilis is the most frequently isolated bacterium from abscesses caused by intestinal bacteria. This is partly because
> D: its ability to resist phagocytosis
Which of the following is not a virulence factor for Helicobacter pylori?
> D: Shiga-like toxin
Shiga toxin
> C: removes a specific adenine base from 28S rRNA, stopping translation
Which of the following is not a property of Pseudomonas aeruginosa?
> E: obligate intracellular pathogen
These gram positive pleiomorphic rods produce a pseudomembrane in the throat that can block the airway.
> C: Corynebacterium diphtheriae
Clostridium botulinum produces an A-B exotoxin that blocks the release of which neurotransmitter from axon endings at neuromuscular junctions?
> A: acetylcholine
Which Clostridial species is part of the normal human bacterial flora?
> B: Clostridium difficile
Which organism produces alpha toxin (a lecithinase-phospholipase C) and theta toxin (a hemolytic toxin), that partially account for the organism’s tissue-destructiveness that often requires amputation to save the patient’s life?
> C: Clostridium perfringens
Which of the following best describes tetanospasmin, a virulence factor for Clostridium tetani?
> D: A-B exotoxin that blocks release of the neurotransmitter glycine
This Gram-negative coccobacillus is transmitted zoonotically mainly from contact with wild animals such as birds, rabbits, or tick bites. The bacteria are able to grow in macrophages, resulting in systemic spread that can lead to ulceroglandular, oculoglandular, and pulmonary infections. A vaccine is available for high-risk individuals.
> B: Francisella tularensis
What virulence property does Haemophilus influenzae capsule b confer on these bacteria?
> A: allows the bacteria to cause systemic infections
What bacterium lives inside amoeba in the environment and is typically transmitted by an aerosol route to humans through ventilation systems in buildings?
> A: Legionella pneumophila
This Gram-negative coccobacillus is transmitted zoonotically via fleas and eventually infects lymph nodes, where it can cause a purulent infection. In some individuals the bacteria can subsequently spread to the lungs and be
transmitted by aerosol from human to human.
> A: Yersinia pestis
Which of the following is true for cord factor of Mycobacterium tuberculosis?
> B: is a glycolipid that adheres to cell surface mycolic acids
Which of the following is true for leprosy?
> A: individuals normally clear the bacterial agent via cell-mediated immunity
Bacteria of which genus are Gram positive filamentous rods that are opportunistic pathogens, causing bronchopulmonary infections and brain abscesses?
> C: Nocardia
A zoonotic disease is associated with which of the following bacteria?
> B: Borrelia burgdorferi
Which form of Chlamydia replicates within a host cell?
> D: reticulate body
What is true about Mycoplasma pneumoniae?
> D: immune protection fades after recovery from infection
Bacteria of which genus cause Rocky Mountain Spotted Fever?
> A: Rickettsia
Which of the following is best associated with the viridans Streptococci?
> C: dental caries
What role does catalase have for those pathogenic bacteria that express it?
> C: Removes hydrogen peroxide produced by phagocytes
Scarlet fever is a caused by what organism?
> A: Streptococcus pyogenes
What symptoms are uniquely associated with tertiary syphilis?
> A: gummas
What is true about antigenic variation involving the pilin protein of Neisseria gonorrhoeae?
> C: involves recombination between silent and expressed copies of the pilin gene
Which of the following virulence factors is the dissaccharide-tetrapeptide component of bacterial peptidoglycan?
> B: tracheal cytotoxin of Bordetella pertussis
Which of the following describes Pseudomonas aeruginosa?
> D: can grow at temperatures up to 43oC
Blockage of acetylcholine release from host cells is caused by a virulence factor of which bacterium?
> D: Clostridium botulinum
What spore forming bacterium produces an A-B exotoxin that blocks GABA (gamma-aminobutyric acid) release from axon endings of interneurons that control motor neurons within muscles?
> B: Clostridium tetani
What bacterium grows at tempertures from 1oC to 45oC, is resistant to salt and acid conditions, and is a food-borne pathogen that causes systemic disease in immune-compromised individuals?
> B: Listeria monocytogenes
What is true about Mycoplasma pneumoniae?
> D: cells pass through filter that traps most other bacteria
What is uniquely associated with congenital syphilis?
> E: Hutchinson’s incisors
A pregnant 22-year-old woman was seen at an urgent care clinic and presented with fever, malaise, headache and a macular rash (flat, red) over much of her body. Upon questioning, she reported that about 1 year earlier she had a painless ulcer on her vagina that healed spontaneously after a few weeks. A diagnostic test revealed the pathogen and the likely connection between her previous and current symptoms. What is the most likely diagnosis made following her urgent care visit?
> C: she has secondary syphilis
Which bacteria are initial colonizers of the dental biofilm, binding to the salivary pellicle?
> C: Streptococcus gordonii
Dental caries correlates with
> C: gingival recession that occurs with age
Which oral bacteria are strongly associated with acute necrotizing ulceratize gingivitis?
> A: spirochetes plus Fusobacterium nucleatum
Which genus is specifically associated with aggressive periodontitis?
> B: Aggregatibacter
Which genus of bacteria are typicaly associated with salivary gland infections?
> D: Staphylococcus
What enzymes create an extracellular network of branched sugar polymers within dental plaque?
> A: glucosyltransferases
How does lysozyme act as an antibacterial agent?
> A: lysozyme cleaves the bond between N-acetylglucosamine and N-acetylmuramic acid
Which of the following is characteristic of periodontal abscesses?
> D: infection contains multiple anaerobic species
Which Streptococcal virulence factor is correlated with the progression of infective endocarditis?
> D: platelet associated aggregation factor
What is an enveloped virus composed of?
> E: nucleocapsid plus membrane plus glycoproteins
Which class of virus always brings its own RNA polymerase into a cell during infection?
> C: negative-sense, single stranded RNA viruses
What virus is responsible for about 30% of cases of the “common cold,” has an RNA genome that can be directly translated into protein, but also requires a second phase of translation to produce several smaller mRNAs transcribed from a negative sense copy of the RNA genome?
> C: coronavirus
What is the receptor for SARS-CoV-2, the agent of COVID-19?
ACE2
Nonpolio enteroviruses such as EV-D68 are associated with increased cases of what disease as a possible emerging epidemic?
> B: acute flaccid myelitis
What virus has an RNA genome that can be directly translated into protein, and transcribes more mRNAs, all of which are the size of the full viral genome, from a negative sense copy of the viral RNA genome?
> A: rhinovirus
What flavivirus is transmitted by mosquitos from person-to-person, can cause jaundice, and was the first virus proven to be spread by an insect vector?
> B: yellow fever virus
Which virus genome is directly translated into proteins upon entry into a cell?
> B: poliovirus
Antigenic shifts in influenza viruses are caused by
> D: random packaging of single stranded RNA genome segments during a coinfection with two types of influenza viruses
What are Koplik’s spots?
> A: lesions of the oral cavity associated with measles
What paramyxovirus initially infects cells of the respiratory tract but characteristically replicates in the parotid gland after viremia?
> D: mumps virus
Members of what minus-stranded RNA virus family are characterized by a helical nucleocapsid and their ability to induce syncytia during infection?
paramyxoviruses
What virus is characterized by cytoplasmic masses of nucleocapsids in brain tissue during the late stages of an infection?
> E: rabies virus
What paramyxovirus is limited to replication in the region of initial contact and does not demonstrate significant spread to other sites by viremia?
> A: respiratory syncytial virus
Cholera toxin has the effect of raising the level of what intracellular signalling molecule? __1__
cAMP
What is the “enterobacterial common antigen”?
> B: core sugars within lipopolysaccharides (LPS)
What is the effect of shiga toxin within a host cell during an infection?
> A: inactivate 60S ribosomal subunit
What is not a property associated with Salmonella enterica serovar typhi?
> C: presence in the oropharynx in asymptomatic carriers
6 What is a property associated with Helicobacter pylori? 1/1
> C: metabolizes urea to make the local environment more basic (increase pH)
What non-invasive bacterium adheres to respiratory tract surfaces where it causes massive mucus production and a characterisitic cough that is severe enough to crack ribs and burst blood vessels?
> A: Bordetella pertussis
8 What is a property of Corynebacterium diphtheriae? 1/1
> C: produces an ADP-ribosylase that targets host elongation factor 2
The ability of Pseudomonas aeruginosa to produce a biofilm is dependent on
> B: alginate production
What is associated with Clostridium difficile?
> E: pseudomembranous colitis
Which Clostridial species is the only one that invades tissue during an infection?
> A: Clostridium perfringens
A vaccine against capsule b polysaccharides is effective for preventing systemic diseases caused by what gram negative cocco-bacilli that are often part of the normal flora of the oropharynx?
> B: Haemophilus influenzae
What bacterium normally lives inside amoeba in the environment and causes a severe pneumonia in elderly individuals?
Answer 1: Legionella
17 Which of the following is true about tuberculosis? 1/1
> D: most individuals exposed to the bacterial agent do not develop disease
18 The Mantoux reaction is the result of a diagnostic test for exposure to what bacterium? __1__ 1/1
Answer 1: Mycobacterium tuberculosis
Which of the following is true for leprosy?
> E: A strong TH1-response by infected individuals results in a good prognosis for recovery
Which organism often produces a characteristic erythema migrans rash in the early stage of infection?
> B: Borrelia burgdorferi
What is true about Mycoplasma pneumoniae?
> D: immune protection fades after recovery from infection
Bacteria of which genus is are obligate intracellular pathogens?
> A: Rickettsia
Name a dental abnormality uniquely associated with congenital syphilis. __1__
Answer 1: mulberry molars
28 Which is a property of bacteria in a dental biofilm is associated with increasing the risk of dental caries? 1/1
> D: increased activity of proton pumps
Dental caries correlates with
> D: high numbers of Streptococcus mutans
What role does ammonia production from arginine and urea play for oral bacteria?
> C: creation of a more basic (pH) local environment
Spirochetes plus Fusobacterium nucleatum are strongly associated with which oral disease?
> E: acute necrotizing ulceratize gingivitis
34 What is an example of a role of a toll-like receptor in oral defense? 1/1
> D: bind to lipopolysaccharide and signal bacterial presence
35 Bacterial aggregates called “sulphur granules” are characteristic of what oral disease? 0/1
> E: cervicofacial actinomycosis
What is a naked capsid virus composed of?
> A: only nucleocapsid
What is true about negative sense, single-stranded RNA viruses?
> A: require a viral RNA polymerase to be packaged into viral particles
What is true about some small positive sense, single-stranded RNA viruses, like hepatitis A virus?
> D: can directly translate viral RNA upon entry into a new host cell
What is an example of a host cell trait supplied by an viral genome integrated into the host cell genome?
> A: diphtheria toxin for Corynebacterium diphtheria
What group of viruses is responsible for about 30% of cases of the “common cold” and has the largest genome of the RNA viruses (up to 30,000 nt)?
Answer 1: coronavirus
What virus has an RNA genome that can be directly translated into protein, and transcribes more mRNAs, all of which are the size of the full viral genome, from a negative sense copy of the viral RNA genome?
> A: poliovirus
What virus is transmitted by mosquitos from person-to-person and causes more severe disease in individuals that have partial immunity from a prior exposure to the virus?
> A: Dengue fever virus
What naked capsid viruses can cause an aseptic meningitis OR vesicles/ulcers on the tonsils and palate OR pleurodynia, depending on the subtype?
> B: coxsackievirus
[FULL CREDIT GIVEN] Which virus is not spread by respiratory transmission?
> A: poliovirus
Which paramyxovirus has an incubation period of over 2 weeks and results in complications that include meningitis and orchitis?
> C: mumps virus
49 Antigenic drift in influenza viruses is caused by 1/1
> B: point mutations that occur during viral genome replication
50 What is true about respiratory syncytial virus? 1/1
> D: can cause bronchiole obstruction
Which of the following is true about Bacillus anthracis?
> A: produces an adenylate cyclase called edema factor
What is the treatment for a child born with congenital syphilis to clear the infection?
Penicillin
What is an example of a host cell trait supplied by an viral genome integrated into the host cell genome?
> A: botulinum toxin for Clostridium botulinum
In addition to multiple drug resistance mechanisms, what is another reason that lung infections with Pseudomonas aeruginosa are so resistant to antibiotic therapy?
> B: the bacterium’s ability to form a biofilm
What is a possible role for the gut bacteriophage community, as presented in lecture?
> D: bacteriophage may limit bacteria in the gut, killing off cells when they reach a high concentration
Members of what enveloped, plus stranded RNA virus family can cause an acute respiratory syndrome that is an atypical pneumonia, but more often cause milder disease, generically referred to as the common cold?
> C: coronavirus
What virus is responsible for about 50% of cases of the common cold, has an RNA genome that can be directly translated into protein, and transcribes more mRNAs that are the size of the full viral genome from a negative sense copy of the viral RNA genome?
> A: rhinovirus
What is true about Zika virus?
> E: It causes congenital infections
Which influenza virus protein mediates adsorption of the virus onto a host epithelial cell surface?
> C: hemagglutinin
What virus is characterized by “negri bodies” in brain tissue?
> E: rabies virus
What is NOT a property associate with the following 3 speicies of bacteria in the oral cavity: Porphyromonas gingivalis, Treponema denticola, and Tannerella forsythia?
> C: they are associated with healthy sites in the mouth
