Deck 18: Haemophilus, Hacek, Legionella, and Other Fastidious Gram-Negative Bacilli

Question 1

What Haemophilus species is called the Koch-Weeks bacillus?

A) H. influenzae
B) H. parainfluenzae
C) H. aegyptius
D) H. aphrophilus

Answer 1

C

Question 2

What organisms often are involved in septicemia in the granulocytopenic patient?

A) Capnocytophaga spp.
B) Eikenella corrodens
C) Kingella spp.
D) Fusobacterium spp.

Answer 2

A

Question 3

What organism causes Brazilian purpuric fever (BPF)?

A) Haemophilus parainfluenzae
B) H. aphrophilus
C) H. aegyptius
D) H. influenzae biogroup aegyptius

Answer 3

D

Question 4

All of the following are normal inhabitants of the human oral cavity, except

A) Capnocytophaga fusofurium.
B) Capnocytophaga gingivalis.
C) Capnocytophaga ochracea.
D) Capnocytophaga haemolyticus.

Question 5

A microbiologist is reading a sputum culture and notices that there is no growth on the sheep blood and MacConkey (MAC) agar plates, but there is heavy growth on the chocolate plate. The colonies on the plate are translucent, moist, smooth, and convex, with a mousy odor. What is the most likely identification of the organism?

A) Haemophilus parainfluenzae
B) H. influenzae
C) H. aegyptius
D) H. ducreyi

Question 6

Which species are associated with infections in humans?

A) Haemophilus influenzae
B) H. aegyptius
C) H. ducreyi
D) All of the above

Question 7

What is the name of the organism that causes tularemia, which can be contracted from rabbits?

A) Brucella tularensis
B) B. hareis
C) Francisella tularensis
D) F. philomiragia

Question 8

A mother brings her lethargic, feverish baby into the emergency department. The baby is diagnosed with meningitis, and the physician does a spinal tap. The cerebrospinal fluid (CSF) Gram stain shows many tiny gram-negative rods. What is the most probable identification of this organism?

A) Haemophilus influenzae
B) H. parainfluenzae
C) H. aegyptius
D) H. aphrophilus

Question 9

What is the most frequently isolated Pasteurella species?

A) P. multocida
B) P. septica
C) P. gallicida
D) P. canis

Question 10

Which one of the virulence factors associated with Haemophilus spp. plays the most significant role in the invasiveness of the organism?

A) IgA protease
B) Pili
C) Capsule
D) Enterotoxin

Question 11

What are the names of the two diseases caused by Legionella species?

A) Rabbit fever and Pontiac fever
B) Scalded skin syndrome and Legionnaires' disease
C) Malta fever and undulating fever
D) Legionnaires' disease and Pontiac fever

Question 12

Which species of Haemophilus requires both X and V factors?

A) H. parainfluenzae
B) H. parahemolyticus
C) H. influenzae
D) H. paraphrophilus

Question 13

All of the following are characteristics of Haemophilus spp., except

A) gram-positive cocci.
B) facultative anaerobes.
C) oxidase positive.
D) catalase positive.

Question 14

The HACEK group includes all of the following, except

A) Haemophilus spp.
B) Aggregatibacter actinomycetemcomitans.
C) Kingella spp.
D) Clostridium difficile.

Question 15

All the following organisms are associated with human illness, except

A) Brucella melitensis.
B) B. ovis.
C) B. suis.
D) B. canis.

Question 16

What organism is likely to cause an infection after a cat bite?

A) Campylobacter spp.
B) Dysgonomonas capnocytophagoides
C) Francisella tularensis
D) Pasteurella spp.

Question 17

What is the drug of choice for treating a life-threatening illness caused by H. influenzae?

A) Penicillin
B) Macrolides
C) Aminoglycosides
D) Ceftriaxone

Question 18

This bacterium is the causative agent of kennel cough in dogs and is occasionally associated with respiratory tract infections in humans.

A) Legionella longbeachae
B) Bordetella bronchiseptica
C) Bordetella parapertussis
D) Aggregatibacter actinomycetmcomitans

Question 19

What medium will sustain the growth of most Haemophilus spp.?

A) Chocolate agar (CHOC)
B) SBA
C) Phenylethyl alcohol
D) Thayer-Martin

Question 20

A microbiologist is reading a sputum culture and notices tiny, translucent colonies growing closely around a $\beta$ hemolytic colony on sheep blood agar (SBA). The colonies are growing in the area where the blood has been hemolyzed. What is the probable identity of the organism that is growing closely to the $\beta$ -hemolytic organism, and why are they growing in the hemolyzed area?

A) Neisseria spp., because they need the factor X in this area
B) Haemophilus spp., because they need the factor V in this area
C) Acinetobacter spp., because they need the factors X and V
D) Aggregatibacter spp., because they need the factors X and V

Question 21

This organism is described as glistening, silver, and resembling a mercury droplet on media supplemented with horse blood.

A) Staphylococcus aureus
B) Bordetella pertussis
C) Streptococcus agalactiae
D) Streptococcus pyogenes

Question 22

All of the following are rapid methods used to definitively identify Legionella species, except

A) direct fluorescent antibody (DFA).
B) DNA detection.
C) indirect immunofluorescence.
D) urine antigen testing.

Question 23

A microbiologist is reading plates from a CSF culture. She notices that there is growth on CHOC, but no growth on SBA or MAC agar. The Gram stain showed a gram-negative bacillus. What organism should be suspected?

A) Streptococcus pneumoniae
B) Staphylococcus aureus
C) Haemophilus influenzae
D) Escherichia coli

Question 24

How is pertussis spread?

A) Fomites
B) Contaminated food
C) Respiratory droplet
D) Airborne

Question 25

A technician is working the night shift and receives a CSF specimen on an infant. The technician makes a Gram stain of the spinal fluid, then reads the smear under the microscope. The report the technician sends to the physician reads as follows: "gram-negative bacillus, small and pleomorphic." What bacteria are being implied as the infecting agent?

A) Escherichia coli
B) Legionella pneumophila
C) Staphylococcus aureus
D) Haemophilus influenzae

Question 26

What organism causes the disease called whooping cough?

A) Bordetella pertussis
B) Legionella pneumoniae
C) Capnocytophagia gingivalis
D) Legionella micdadei

Question 27

What organism produces a community-acquired pneumonia, with symptoms different than a Streptococcus pneumoniae infection, leading to the designation of atypical pneumonia?

A) Legionella pneumophila
B) Eikenella corrodens
C) Pasteurella multocida
D) Kingella oralis

Question 28

What medium is used to isolate Legionella?

A) MAC
B) Buffered charcoal yeast extract (BCYE)
C) Chocolate
D) Bordet-Gengou

Question 29

What agar is used to isolate Bordetella pertussis?

A) Loeffler's
B) Bordet-Gengou
C) Chocolate
D) Martin-Lewis

Question 30

What is the drug of choice for treating a Legionella infection?

A) Aminoglycosides
B) Penicillin
C) Vancomycin
D) Macrolide

Question 31

What is the specimen of choice for Bordetella pertussis?

A) Throat cultures
B) Sputum specimens
C) Bronchial aspirations
D) Nasopharyngeal swabs

Question 32

A microbiologist is reading the plates from a sputum culture. There is growth only on the chocolate plate. When the microbiologist takes off the lid of the culture plate, he notices a distinct "mousy" smell. What organism can this be?

A) Proteus mirabilis
B) Haemophilus sp.
C) Staphylococcus aureus
D) Pseudomonas aeruginosa

Question 33

What is the drug of choice for treating Bordetella pertussis infection?

A) Erythromycin
B) Penicillin
C) Aminoglycosides
D) Quinolones