4Hansen's disease, leprosy Chronic granulomatous communicable disease occurring in tropical and subtropical regions; characterized by inflamed nodules beneath the skin and wasting of body parts; caused by the Mycobacterium leprae.Chronic disease, disfigurement, common in third world, millions of casesInfects the skin –neural involvement, low temperature
14Skin biopsy shows intradermal formation of epithelioid granulomas without caseous necrosis (HE). The papillary dermis is involved. Acid-fast staining is negative. Diagnostic hints include clinical information of numbness and histologic identification of nerve involvement by the granulomatous lesion.
15Lepromatous leprosy (35 y-o) Male Biopsy from erythematous and scaling nodules on the extremities. The bacilli forming "globi" are stained with PAS method.
16Lepromin testA test utilizing an intradermal injection of a lepromin, such as the Dharmendra antigen or Mitsuda antigen, to classify the stage of leprosy based on the lepromin reaction, such as the Fernandez reaction or Mitsuda reaction.It differentiates tuberculoid leprosy, in which there is a positive delayed reaction at the injection site, from lepromatous leprosy, in which there is no reaction (i.e., a negative test result) despite the active malignant Mycobacterium leprae infection; the test is not diagnostic, since normal uninfected persons may react.
17Erythema Nodosum Leprosum (ENL) An inflammatory complication of leprosy that results in painful skin lesions on the arms and legs and faceCause – Type III hypersensitivity Immune complex Vasculitis.
18Lab Diagnosis Leprosy Easy in Lepromatous, difficult in Tuberculoid. Demonstration of AFBNasal mucosaSkin LesionEar lobuleSkin clippings from 5-6 areasButtocksForeheadChinCheekEar
24M. avium is much less virulent than M. tuberculosis Mycobacteria and AIDSM. avium is much less virulent than M. tuberculosisdoes not infect healthy peopleinfects AIDS patientsM. avium infectswhen CD4 (helper T cell) count greatly decreasedM. tuberculosis infectioninfects healthy peopleearlier stage of diseasemore systemic
25Other atypicals pigmented or not pigmentation in the light in the dark growthfastslow
26Mycolic acids mycobacteria longest chain length strongly acid fast nocardiaintermediate chain lengthweakly acid fastcorynebacteriashortest chain lengthnot acid fast
27Most found in US – Rare in Africa. Annual frequency in AIDS – 10-20%. Mycobacterium avium complex (MAC)Most common bacterial opportunistic infection (OI) in adults infected with HIV in the developed world.Most found in US – Rare in Africa.Annual frequency in AIDS – 10-20%.Occurs late in HIV infection. Mean CD4+ Count ~ 10-30/μL. (TB occurs early.)Inhaled or ingested from environment.Spreads via lymphatics then hematogenously.Taken up in reticuloendothelial organs.
28Mycobacterium avium complex (MAC) Symptoms in the AIDS Patient: Disseminated GastrointestinalFever Chronic Diarrhea & Night Sweats Abdominal PainWeight Loss MalabsorptionMalaise Cholestatic JaundiceAnemiaElevated LFTs(Alkaline Phosphatase)
29MAC in the Non-HIV/AIDS Patient: More common as a cause of pulmonary disease in persons born in United States than TB.2) Increasing in incidence over the last years.3) Progressive pulmonary disease on x-ray and clinically.4) Sputum culture positive.5) Dissemination rare to non-existent.
30Diagnosis of MAC in AIDS Biopsy of the involved reticuloendothelialorgans with acid fast stain and/or culture.Blood culture. (85% ofpatients with disseminatedMAC are mycobacteremic.)EID CDC
33NAME OF DISEASE: Buruli ulcers, Mycoburuli ulcers ETIOLOGICAL AGENT:Mycobacterium ulcerans. It grows only at temperatures below 37° C, is non-chromogenic and niacin-negative and extracellular OVERVIEW:An ulcer of the skin and underlying tissue is the sole symptom due to the unique temperature requirements of the organism. The disease is most common along the Nile River but is also found in Southeast Asia, Australia and Mexico.PATHOGENESIS:The organism can apparently penetrate the unbroken skin where it produces an ulcer. Despite extensive necrosis, lesions are painless, symptoms of systemic disease are absent and there is little histological evidence of an initial acute inflammatory response. Focal necrosis extends through the dermis and adipose tissue and into muscle. The cause of this necrosis is mycolactone.
34Mycobacterium marinum Swimming pool granuloma: Localized nodular skin inflammation (small reddish raised areas of skin) caused by a bacterium called Mycobacterium marinumAtypical Mycobacterium found in salt and fresh water. M marinum is the most common atypical Mycobacterium to cause infection in humans. Infection occurs following primary inoculation of a skin abrasion or puncture and manifests as a localized granulomaContact with an aquarium, salt water, or marine animals such as fish or turtles. Exposure to M marinum via swimming pools is rare these days because most pools are chlorinated.Cultures at 25-32°C may grow acid-fast bacilli in 7-21 days. The organisms are photochromogens