Unit 4 - Miscellaneous gram-negative bacteria

Question 1

What is the morphology of Streptobacillus moniliformis?

Answer 1

highly pleomorphic rod or filament

Question 2

What does Streptobacillus moniliformis cause?

Answer 2

rat-bite fever or Haverhill fever in humans, it can produce epizootics in mice and rats as well

Question 3

How does Streptobacills moniliformis grow?

Answer 3

it may require anaerobic conditions for primary culture and it may require serum or special media

Question 4

In regards to oxygen, what type of organism is Streptobacills moniliformis?

Answer 4

it is a facultative anaerobe

Question 5

What is the natural habitat of Streptobacillus moniliformis?

Answer 5

nasopharynx of rats and sometimes small rodents, pigs, dogs, and cats

Question 6

How is Streptobacillus moniliformis transmitted in laboratory mice?

Answer 6

it can be spread by bites, contact, and through feed and water

Question 7

What will Streptobacillus moniliformis cause in affected mice?

Answer 7

swelling of the extremites, arthritis, conjunctivitis, and high fever

Question 8

What does Streptobacillus moniliformis cause in rats?

Answer 8

bronchopneumonia, middle ear infections, and conjunctivitis

Question 9

What does rat-bite fever cause?

Answer 9

the lymphatics are inflamed and the patient usually spikes an abrupt fever with chills, the temperature falls within 36 hours and the patient remains normal for 3-9 days - then the patient will redevelop the fever

Question 10

Aside from fever, what clinical signs are associated with Streptobacillus moniliformis?

Answer 10

rash, bacterial endocarditis, meningitis, pneumonia, and polyarthralgia (2/3 of the patients)

Question 11

What is the difference between rat-bite fever and haverhill fever?

Answer 11

They both share the same clinical signs but GI and respiratory signs are more common with Haverhill fever. The organism is also transmitted to humans by ingestion in food or water contaminated with the organism from rats

Question 12

What does Spirillum minus cause and where?

Answer 12

rat-bite fever in humans that is more common in Asia and Africa but does not affect animals

Question 13

What lesion is associated with Spirillum minus infection?

Answer 13

a darkened purplish lesion at the site of the bite, a chancre-like ulcerated lesion develops that is quite painful - lymph node involvement is characteristic

Question 14

What is Bartonella henselae the cause of?

Answer 14

cat scratch disease in humans

Question 15

How do you tell if a cat is a carrier for Bartonella henselae?

Answer 15

by serologic testing and culture of the blood

Question 16

What does Bartonella henselae cause in cats?

Answer 16

a systemic bacteremia that does not seem to be associated with any clinical disease

Question 17

What does cat scratch disease cause in humans?

Answer 17

granulomatous regional lymphadenitis

Question 18

What clinical signs are associated with Bartonella henselae infection in humans?

Answer 18

swollen lymph nodes, fever, anorexia, fatigue, and a headache

Question 19

How is Bartonella henselae treated?

Answer 19

prolonged treatment with doxycycline, fluoroquinolones, and aminoglycosides

Question 20

How is Bartonella henselae diagnosed?

Answer 20

by skin test or microscopic examination of Warthin-Starry stained-smears from lymph node aspirates

Question 21

What disease is Afipia felis associated with?

Answer 21

cat scratch disease

Question 22

What does Bartonella quintana cause and by what?

Answer 22

trench fever, a disease spread by the body louse in humans

Question 23

What is trench fever characterized as?

Answer 23

relapsing fever, arthritis, leg pain, headache, and occastionally endocarditis

Question 24

How long does it take to grow Bartonella quintana?

Answer 24

20 to 40 days

Question 25

How is Bartonella quintana treated?

Answer 25

with extended antibiotic therapy

Question 26

What is the natural habitat of Capnocytophaga?

Answer 26

they are commensals of the nasopharynx and oral cavities of humans, dogs, and other animals

Question 27

What infections can be caused by Capnocytophaga?

Answer 27

infections can vary from a local inflammation to severe septicemia with endocarditis and meningitis