Finals Flashcards
The potentially lethal intoxication type of food poisoning often associated with improperly canned food is caused by
A. Bacteroides Fragilis
B. Clostridium botulinum
C. Clostridium perfringens
D. Clostridium septicum
B. Clostridium botulinum
Which of the following is not considered a zoonotic disease?
A. Anthrax
B. Botulism
C. Brucellosis
D. Leptospirosis
B. Botulism
An anaerobically incubated blood agar plate shows colonies
surrounded by an inner zone of complete red cell lysis and an outer zone of incomplete cell lysis (double zone of hemolysis). The most likely presumptive identification of this isolate would be
A. Clostridium perfringens
B. Clostridium tetani
C. Fusobacterium nucleatum
D. Prevotella melaninogenica
A. Clostridium perfringens
A cervical mucosal abscess specimen was sent to the laboratory
for bacteriologic examination. The culture of this sample grew an anaerobic gram-negative bacillus that was inhibited by bile, produced a black pigment, and was negative for indole
production and positive for glucose, sucrose, and lactose fermentation. This isolate would most likely be:
A. Bacteroides fragilis group
B. Bacteroides ureolyticus
C. Porphyromonas gingivalis
D. Prevotella melaninogenica
D. Prevotella melaninogenica
Which one of the following is not true of Clostridium tetani ?
A. It produces rapid tissue necrosis.
B. It is a gram-positive, spore-forming bacillus.
C. Microorganisms in soil contaminate puncture wounds.
D. Disease is caused by an exotoxin acting on the central
nervous system
A. It produces rapid tissue necrosis.
The characteristic colony morphology of Actinomyces israelii on
solid agar resembles
A. “Medusa head”
B. A molar tooth
C. A fried egg
D. Ground glass
B. A molar tooth
What is the predominant indigenous flora of the colon?
A. Anaerobic, gram-negative, non-sporeforming bacteria
B. Anaerobic, gram-positive, non-sporeforming bacteria
C. Aerobic, gram-negative, non-sporeforming bacteria
D. Aerobic, gram-positive, spore-forming bacteria
A. Anaerobic, gram-negative, non-sporeforming bacteria
Obligately anaerobic, gram-negative bacilli, recovered from an abdominal wound, were found to be resistant to penicillin. Growth of this organism was not inhibited by bile. What is the most likely identification of this isolate?
A. Bacteroides fragilis group
B. Clostridium septicum
C. Eubacterium lentum
D. Fusobacterium nucleatum
A. Bacteroides fragilis group
Which of the following is described as obligately anaerobic gram-positive cocci?
A. Capnocytophaga
B. Peptostreptococcus
C. Propionibacterium
D. Veillonella
B. Peptostreptococcus
Color Plate 29 * shows the filamentous gram-positive rod recovered from an aspirate of a closed chest abscess. It grew only under anaerobic conditions and was not acid-fast. What is the most likely presumptive identification of the isolate seen?
A. Actinomyces israelii
B. Bacteroides fragilis
C. Clostridium septicum
D. Propionibacterium acnes
A. Actinomyces israelii
Growth on kanamycin-vancomycin laked blood agar incubated anaerobically is primarily used for
A. Bacteroides fragilis
B. Bifidobacterium dentium
C. Clostridium perfringens
D. Peptostreptococcus anaerobius
A. Bacteroides fragilis
The diagnosis of pseudomembranous colitis (Clostridium difficile associated disease) is often made by
A. Serology
B. Culturing blood specimens
C. Assays to detect toxin in stool
D. Acid-fast stain of fecal material
C. Assays to detect toxin in stool
The anaerobic, gram-negative, curved, motile bacilli associated with bacterial vaginosis belong to the genus
A. Actinomyces
B. Bifidobacterium
C. Lactobacillus
D. Mobiluncus
D. Mobiluncus
An infant was seen in the emergency department with symptoms of neuromuscular weakness and constipation. The diagnosis of infant botulism was confirmed by the demonstration of toxin in the child’s stool. The child most likely contracted this disease by
A. A scratch wound caused by a cat
B. Ingestion of spores that germinated in the intestine
C. A puncture wound with a contaminated household item
D. Ingestion of preformed toxin found in a contaminated jar of
pureed vegetables
B. Ingestion of spores that germinated in the intestine
The majority of the gram-positive, nonspore-forming, anaerobic
bacilli isolated from clinical material will be
A. Bifidobacterium dentium
B. Capnocytophagia ochracea
C. Eubacterium limosum
D. Propionibacterium acnes
D. Propionibacterium acnes
Which of the following clostridia has a terminal spore that causes the cell to swell?
A. C. botulinum
B. C. difficile
C. C. perfringens
D. C. tetani
D. C. tetani
The gram-negative, non-spore-forming, anaerobic bacillus frequently implicated in serious clinical infections such as brain and lung abscesses is
A. Bacteroides urealyticus
B. Eubacterium lentum
C. Fusobacterium nucleatum
D. Peptostreptococcus anaerobius
C. Fusobacterium nucleatum
Which one of the following is a non-spore-forming,
gram-positive, anaerobic bacillus?
A. Clostridium
B. Fusobacterium
C. Propionibacterium
D. Veillonella
C. Propionibacterium
Which of the following statements is not characteristic of Clostridium botulinum?
A. Infant botulism is the most common clinical form.
B. Pathogenicity is related to a potent neuro toxin.
C. Oval spores are located terminally.
D. Of the seven toxogenic types, types A, B, E, and F are associated with human botulism.
C. Oval spores are located terminally.
A tube of semisolid medium that contains resazurin appears pink. What does this indicate?
A. Acid environment
B. Alkaline environment
C. Motility
D. Presence of oxygen
D. Presence of oxygen
Identify the Fusobacterium sp. considered to be the most frequent isolate recovered from clinical infections.
A. F. varium
B. F. nucleatum
C. F. mortiferum
D. F. necrophorum
B. F. nucleatum
Septicemia caused by which of the following is generally associated with an underlying malignancy?
A. Bifidobacterium dentium
B. Clostridium septicum
C. Eubacterium lentum
D. Lactobacillus catenaforme
B. Clostridium septicum
Which of the following is the most potent bacterial exotoxin known?
A. Botulinum toxin
B. Erythrogenic toxin
C. C. difficile toxin B
D. C. perfringens alpha-toxin
A. Botulinum toxin
Which Clostridium sp. is most commonly recovered from cases of gas gangrene?
A. C. bifermentans
B. C. perfringens
C. C. sordellii
D. C. difficile
B. C. perfringens
Which of the following organisms is not gram-positive?
A. Eubacterium lentum
B. Bifidobacterium dentium
C. Propionibacterium acnes
D. Suttonella wadsworthensis
D. Suttonella wadsworthensis
Which of the following statements is not true of clostridia?
A. Pseudomembranous colitis is due to a toxin produced by C. difficile.
B. Clinically significant clostridia are found in the normal flora of the colon and in the soil.
C. Botulism is caused by ingesting preformed toxin and can be prevented by boiling food prior to eating.
D. C. tetani spores will form in the presence of oxygen; therefore, anaerobiosis in a wound is not required to cause tetanus
D. C. tetani spores will form in the presence of oxygen; therefore, anaerobiosis in a wound is not required to cause tetanus
Gram-positive bacilli with central spores are seen in the direct Gram stain of a tissue biopsy. After 24 hours of incubation, no growth is seen on the sheep blood agar plate incubated aerobically and the chocolate agar plate incubated in increased CO2. Which of the following is the likely cause of the infection?
A. Bacillus
B. Clostrdium
C. Lactobacillus
D. Prevotella
B. Clostrdium
Small alpha-hemolytic colonies are seen on a sheep blood agar plate after 48 hours of incubation on a vaginal culture. This describes which of the following?
A. Bacteroides
B. Clostridium
C. Lactobacillus
D. Porphyromonas
C. Lactobacillus
Which of the following statements is true regarding Clostridium perfringens?
A. There are five serologic types
B. Sppres are terminally located
C. Alpha-toxin is produced by all strains
D. Spores are readily seen in laboratory media
C. Alpha-toxin is produced by all strains
Which is a correct statement regarding Clostridium tetani?
A. It is proteolytic
B. It is lecithinase positive
C. It is characteristically nonmotile
D. It produces terminal spores
D. It produces terminal spores
Which anaerobic, gram-negative rod can be presumptively identified by its Gram stain morphology, and inhibition by bile and a 1-jag kanamycin disk?
A. Bacteroides fragilis group
B. Eubacterium lentum
C. Fusobacterium nucleatum
D. Porphyromonas gingivalis
C. Fusobacterium nucleatum
Which of the following tests is most appropriate for the presumptive identification of Prevotella melaninogenica?
A. SPS sensitivity test
B. Naglertest
C. Cytotoxin assay
D. Fluorescence test
D. Fluorescence test
Which of the following tests is most appropriate for the identification of Clostridium difficile?
A. SPS sensitivity test
B. Naglertest
C. Cytotoxin assay
D. Fluorescence test
C. Cytotoxin assay
Which of the following tests is most appropriate for the presumptive identification of Clostridium perfringens?
A. SPS sensitivity test
B. Reverse CAMP test
C. Cytotoxin assay
D. Esculin hydrolysis
B. Reverse CAMP test
Which of the following tests is most appropriate for the presumptive identification of Peptostreptococcus anaerobius?
A. SPSdisk
B. Colistindisk
C. Kanamycin disk
D. Vancomycin disk
A. SPSdisk
A curved appearance on Gram stain is characteristic of which of the following?
A. Actinomyces israelii
B. Clostridium septicum
C. Fusobacterium nucleatum
D. Propionibacterium acnes
C. Fusobacterium nucleatum
Pumlent material from a cerebral abscess was submitted to the laboratory for smear and culture. On direct Gram stain, gram positive cocci in chains and gram-negative bacilli with pointed ends were seen. Plates incubated aerobically exhibited no growth at 24 hours. On the basis of the organisms seen on the smear, what is the most likely presumptive identification of the etiologic anaerobic agents?
A. Veillonella sp. and Clostridium sp.
B. Eubacterium sp. and Veillonella sp.
C. Peptostreptococcus sp. and Nocardia sp.
D. Fusobacterium sp. and Peptostreptococcus sp.
D. Fusobacterium sp. and Peptostreptococcus sp.
Which of the following is an important virulence factor of Bacteroides fragilis?
A. Endotoxin
B. Exotoxins
C. Polysaccharide capsule
D. Protease
C. Polysaccharide capsule
Which of the following is not true of Bacteroides fragilis ?
A. Lipase and lecithinase negative
B. Anaerobic gram-negative bacillus
C. Commonly associated with intraabdominal infections
D. Among the most antimicrobialsensitive anaerobic bacteria
D. Among the most antimicrobialsensitive anaerobic bacteria
Aspiration of vomitus can lead to pneumonia. Which of the following would not be a likely causative agent in aspiration pneumonia?
A. Bacteroides gracilis
B. Mobiluncus sp.
C. Porphyromonas sp.
D. Prevotella melaninogenica
B. Mobiluncus sp.
To ensure that anaerobic conditions have been achieved in anaerobic jars or chambers, an oxygen-sensitive indicator is employed, such as
A. Bromcreosol purple
B. Methylene blue
C. Methyl red
D. Phenol red
B. Methylene blue
Egg yolk agar showing a precipitate in the medium surrounding the colony is positive for
A. Lecithinase production
B. Lipase production
C. Protease activity
D. Starch hydrolysis
A. Lecithinase production
After 72 hours of anaerobic incubation, small olive-green to black colonies are seen. A Gram stain reveals gram-postive cocci. What is the most likely identification of this organism?
A. Fingoldia magna
B. Peptococcus niger
C. Peptostreptococcus anaerobius
D. Veillonella parvula
B. Peptococcus niger
Which of the following is an important cause of food poisoning?
A. Bacteroides fragilis
B. Bacteroides ureolyticus
C. Clostridium perfringens
D. Clostridium histolyticum
C. Clostridium perfringens