Atypical Mycobacterium

1. Mycobacterium kansaii

   1. Photochromogenic-dark color producer, yellow-pigemneted, colonies after 2 weeks in light

   2. Prevalent since M. tb has declined. IL, OK, and TX urban areas 3% mycobacterial ifx in ES

   3. Cavitary pulmonary disease, cervical lymphadenitis, and skin infections. Causes disease in HIV patient and CD4+ Tcell counts lower than 200.

   4. PPD +

   5. Prolonged chemotherapy with isoniazid, rifampin, and ethambutanol

2. M. avium-intracellalare (MAI)

   1. Slightly faster faster than M. tb. Acid-fast. Found in macrophages

   2. world-wide in soil and water. US- SE, Pacific coast, and north –central regions.

   3. 2^nd to tb in significance and frequency

   4. M. avium- birds, M. intracellulare- systemic HIV infx

   5. Blood culture

3. M. scrofulaceum

   1. Acid-fast, scotochromagen, makes yeloow colonies in light or dark after 2 weeks

   2. Granulomatous cerivical lymphadenitis, scrofula, in children

   3. Manifests as an enlargement of one or more lymph nodes. Little or no pain. PPD-

   4. Surgical removal

4. M. fortuitum complex

   1. free-living, rapidly growing, acid-fast bacterium which produce colonies in 3 days

   2. Human infx rare

   3. Abscess @ injection sites of IV drug abusers are the most common lesions. Secondary pulmonary infx

5. M. marinu-

   1. grows @ 30C not @37C, photochromagen- color producer

   2. water and fish natural sources, slime on sides of swimming pools- skin superficial granulomatous lesion that ulcerates

   3. heals spontaneously in a few weeks, tetracycline and other tb drugs

6. M. ulcerans-

   1. grows @ 30C not @37C

   2. most cases in tropics: Africa, New Guinea, and N. Australia. Children mostly infected.

   3. Severe ulceration on skin and subcu tissue

   4. Surgical excision and grafting. Drugs not successful.

Category: Microbiology Notes