Actinomyces israelii - Mycobacterium avium complex Flashcards
This bacterium is a Gram + anaerobe with filamentous branching. It is a non-acid fast rod. It is identified by presence of sulfur granules in infected tissues (orange). The culture shows molar tooth appearance after 1 week.
Actinomyces israelii
How is Actinomyces israelii spread and where does it colonize?
spread world-wide from person to person
colonizes in mouth, colon, vagina (endogenous spread from mouth)
note: it is more common in men
This type of actinomycosis results in soft tissue swelling, abscess, or mass lesions containing sulfur granules, and is often mistaken as neoplasm. It may spread to head, spine, or thorax
cervicofacial actinomycosis
This type of actinomycosis is progressive, and located in the pulmonary parenchyma and/or pleural space. The chest X-ray shows mass lesion
Thoracic actinomycosis
This type of actinomycosis takes months to years to develop following an event (appendicitis, diverticulitis, etc.). Any abdominal organ may be involved. It usually presents as an abscess or mass lesion
abdominal/pelvic actinomycosis
In regards to virulence, actinomyces israelii infection can occur when the ____ barrier is harmed by trauma/surgery
mucosal
This bacterium is a Gram + filamentous rod with branched hyphae and a short mycolic acid chain. It is a weak acid fast + bacterium.
Nocardia
How is Nocardia identified?
look for branched filamentous Gram + rods in sputum or pus. BYCE agar shows aerial hyphae
Where is Nocardia found and how does it spread?
found worldwide, saprophyte soil
it is seen mostly in Aids/IC people and after local trauma; acquired by inhalation
This type of nocardiosis is most common. It is usually sub-acute and presents with nodules, abscesses, emphysema, prominent coughing with small amount of purulent sputum
bronchopulmonary nocardiosis
This type of nocardiosis is painless and localized with S/C tissue swelling and suppuration (pus formation) with multiple sinus tracts
Cutaenous nocardiosis
Nocardiosis forms an ____ with PMN infiltration. ___ factor prevents acidification of phagosome. ___ is needed to clear infection
abscess; cord; CMI
This bacterium is aerobic, acid fast, rod with lipid coat linked to arabinogalactan and peptidoglycan. It can survive in latent infections for decades and is very very slow growing (24 hour doubling time)
M. tuberculosis
How is M. tuberculosis Id’d?
Mantoux test; acid fast stain growth on Lowenstein-Jensen or Middlbrook 7H10/7H11 agar, PCR QuantiFERON-TB Gold test
How is M. tuberculosis spread? How long does it take for infection to present?
resp. droplets must be inhaled
primary TB: after first exposure, lower transmission rate, only 10% get it, CMI can place it in granulomas and it can burst years later to cause second degree TB
What are the symptoms of primary TB?
flu-like illness, CMI control of MTB -> calcified lung lesions (Ghon focus), fever, cough, night sweats, weight loss
M. tuberculosis best grows in regions with high ___ (kidneys vertebral bodies)
O2
This bacterium is a slow grower. It’s an acid fast intracellular parasite. It has a 5 yr incubation period (up to 20 yrs). it doesn’t do well at temps over 30 degrees celsius and impacts only the skin.
M. leprae
How is M. leprae Id’d?
skin biopsy and acid fast staining
How is M. leprae spread? Who is at risk?
due to CMI, not readily contagious; the early stages are most infectious; it is transmitted through skin/mucus lining of nose and throat
children are more susceptible
Describe the progression of the M. leprae infection
very slow progression - begins as attack on dermis -> nerve sheath (may lead to loss of sensation)
This type of leprosy is a limited disease with a few bacteria in the skin/nerves which have a few flat or slightly raised lesions of differing sizes that may be pale or reddish, dry, hairless, and numb to the touch
tuberculoid lepropsy
This type of leprosy is a widespread disease with lots of bacteria and a diffuse involvement of skin and thickening of many peripheral nerves
Lepromatous leprosy
M. marinum and M. ulcers cause skin infections, commonly known as ___ ____ granulomas
swimming pool
The mycobacterium avium complex is composed of two species. What are they?
m. avium and m. intracellulare
In what individuals is the mycobacterium avium complex commonly seen in?
AIDS and IC people
note: its the most common non-MTB infection. In AIDS, 50% of patients get this infeciton
What are the symptoms of MAC infection?
disseminated infection; fever, swollen lymph nodes, diarrhea, fatigue, weight loss
