Unit 4 - Miscellaneous gram-negative bacteria Flashcards
What is the morphology of Streptobacillus moniliformis?
highly pleomorphic rod or filament
What does Streptobacillus moniliformis cause?
rat-bite fever or Haverhill fever in humans, it can produce epizootics in mice and rats as well
How does Streptobacills moniliformis grow?
it may require anaerobic conditions for primary culture and it may require serum or special media
In regards to oxygen, what type of organism is Streptobacills moniliformis?
it is a facultative anaerobe
What is the natural habitat of Streptobacillus moniliformis?
nasopharynx of rats and sometimes small rodents, pigs, dogs, and cats
How is Streptobacillus moniliformis transmitted in laboratory mice?
it can be spread by bites, contact, and through feed and water
What will Streptobacillus moniliformis cause in affected mice?
swelling of the extremites, arthritis, conjunctivitis, and high fever
What does Streptobacillus moniliformis cause in rats?
bronchopneumonia, middle ear infections, and conjunctivitis
What does rat-bite fever cause?
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
Aside from fever, what clinical signs are associated with Streptobacillus moniliformis?
rash, bacterial endocarditis, meningitis, pneumonia, and polyarthralgia (2/3 of the patients)
What is the difference between rat-bite fever and haverhill fever?
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
What does Spirillum minus cause and where?
rat-bite fever in humans that is more common in Asia and Africa but does not affect animals
What lesion is associated with Spirillum minus infection?
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
What is Bartonella henselae the cause of?
cat scratch disease in humans
How do you tell if a cat is a carrier for Bartonella henselae?
by serologic testing and culture of the blood
What does Bartonella henselae cause in cats?
a systemic bacteremia that does not seem to be associated with any clinical disease
What does cat scratch disease cause in humans?
granulomatous regional lymphadenitis
What clinical signs are associated with Bartonella henselae infection in humans?
swollen lymph nodes, fever, anorexia, fatigue, and a headache
How is Bartonella henselae treated?
prolonged treatment with doxycycline, fluoroquinolones, and aminoglycosides
How is Bartonella henselae diagnosed?
by skin test or microscopic examination of Warthin-Starry stained-smears from lymph node aspirates
What disease is Afipia felis associated with?
cat scratch disease
What does Bartonella quintana cause and by what?
trench fever, a disease spread by the body louse in humans
What is trench fever characterized as?
relapsing fever, arthritis, leg pain, headache, and occastionally endocarditis
How long does it take to grow Bartonella quintana?
20 to 40 days
How is Bartonella quintana treated?
with extended antibiotic therapy
What is the natural habitat of Capnocytophaga?
they are commensals of the nasopharynx and oral cavities of humans, dogs, and other animals
What infections can be caused by Capnocytophaga?
infections can vary from a local inflammation to severe septicemia with endocarditis and meningitis
