MYCOBACTERIA 2/2MYCOBACTERIA 2/2M. leprae & AtypicalM. leprae & Atypical

Professor Sudheer Kher

KEYWORDSKEYWORDS• Acid Fast• Ziehl-Neelsen Stain

– 5% H2SO4

• Mycolic acids• M. leprae• Non cultivable• Armadillo, Mouse footpad• Lepromin test• Ridely Jopling

classification Tuberculoid / Lepromatous

• Lab diagnosis –Skin clippings

• Atypical• Runyon groups• Antibiotic

resistance• Opportunistic

infection

• Skin pathogens M.marinum & M. ulcerans

• Buruli ulcer

MycobacteriaMycobacteria

Mycobacterium lepraeMycobacterium leprae

Chronic granulomatous communicable Chronic granulomatous communicable disease occurring in tropical and disease occurring in tropical and subtropical regions; characterized by subtropical regions; characterized by inflamed nodules beneath the skin and inflamed nodules beneath the skin and wasting of body parts; caused by the wasting of body parts; caused by the Mycobacterium leprae.Mycobacterium leprae.

•Chronic disease, disfigurement, common in third world, Chronic disease, disfigurement, common in third world, millions of cases millions of cases •Infects the skin –neural involvement, low temperatureInfects the skin –neural involvement, low temperature

Hansen's disease, leprosy

Ridley Jopling Classification of Leprosy Ridley Jopling Classification of Leprosy Basis - ImmunologicalBasis - Immunological

RR-Reversal reaction; ENL-Erythema nodosum leprosum; PB-Paucibacillary, MB-Multibacillary

Ulcers, resorption of bone worsened from careless use of hands (nerve damage)Ulcers, resorption of bone worsened from careless use of hands (nerve damage)

• tuberculoidtuberculoid• few organisms few organisms • active cell-mediated immunityactive cell-mediated immunity

• lepromatous lepromatous • many organisms many organisms • immunosuppressionimmunosuppression

LeprosyLeprosy

• in vitroin vitro – uncultivable uncultivable

• in vivoin vivo growth growth– low temperaturelow temperature– armadillo armadillo – mouse footpadmouse footpad

Production of Production of M. leprae M. leprae antigens and antigens and pathogenesis studiespathogenesis studies

• lepromin lepromin – skin testingskin testing

• acid-fast stains acid-fast stains – skin biopsiesskin biopsies

• clinical picture clinical picture

LeprosyLeprosy

Tuberculoid Leprosy

Lepromatous leprosy

Skin 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.

Lepromatous leprosy (35 y-o) Male          

Biopsy from erythematous and scaling nodules on the extremities. The bacilli forming "globi" are stained with PAS method.

Lepromin test

A 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.

An inflammatory complication of leprosy that results in painful skin lesions on the arms and legs and face

Cause – Type III hypersensitivity Immune complex Vasculitis.

Erythema Nodosum Leprosum (ENL)

Lab Diagnosis Leprosy

• Easy in Lepromatous, difficult in Tuberculoid.• Demonstration of AFB

– Nasal mucosa– Skin Lesion– Ear lobule

• Skin clippings from 5-6 areas– Buttocks– Forehead– Chin– Cheek– Ear

MycobacteriaMycobacteria

Atypical MycobacteriaAtypical Mycobacteria

Mycobacteria other than human or bovine tubercle

Synonyms –• Atypical• Anonymous• Unclassified• Non tuberculous mycobacteria• Paratubercle• Tuberculoid• MOTT Mycobacteria Other Than Tubercle

Runyon Classification (1959)Runyon Classification (1959) Basis – Pigment production & Rate of growth

• Group I – Group I – PhotochromogensPhotochromogens– Form pigment after

exposure to light– Example – M. kansasii – Habitat – Water & animals– Causes Pulmonary, skin,

systemic, LN infections.

• Group II – Group II – ScotochromogensScotochromogens– Pigment produced in dark– Example – M. scrofulaceum– Habitat – Water, soil,

fomites– Causes cervical

lymphadenitis in children

• Group III- Group III- NonphotochromogensNonphotochromogens– No pigment production– Examples – M. intracellulare,

M. avium & M. xenopi– Habitat – Soil, Seawater,

animals– Causes Pulmonary,

gastrointestinal, renal, systemic, LN infections

Pulmonary, epididymis

• Group IV –Rapid growersGroup IV –Rapid growers– Colonies appear within seven

days– Example –M. fortuitum, – Habitat- Water, soil & animals– Causes Pulmonary,

gastrointestinal, renal, systemic, LN infections

Atypical mycobacteriaAtypical mycobacteria

• infect immunocompromised hostinfect immunocompromised host• not transmitted man -mannot transmitted man -man

– healthy peoplehealthy people

• tuberculosis-like tuberculosis-like • leprosy-likeleprosy-like

Atypical mycobacterial diseasesAtypical mycobacterial diseases

• M. avium M. avium is much less virulent than is much less virulent than M. tuberculosisM. tuberculosis– does not infect healthy peopledoes not infect healthy people– infects AIDS patientsinfects AIDS patients

• M. aviumM. avium infects infects– when CD4 (helper T cell) count greatly decreasedwhen CD4 (helper T cell) count greatly decreased

• M. tuberculosisM. tuberculosis infection infection– infects healthy peopleinfects healthy people– infects AIDS patientsinfects AIDS patients

* earlier stage of diseaseearlier stage of disease* more systemicmore systemic

Mycobacteria and AIDSMycobacteria and AIDS

Other atypicalsOther atypicals

• pigmented or notpigmented or not• pigmentation pigmentation

– in the light in the light – in the darkin the dark

• growthgrowth– fastfast– slow slow

Mycolic acidsMycolic acids• mycobacteriamycobacteria – longest chain lengthlongest chain length– strongly acid faststrongly acid fast

• nocardia nocardia – intermediate chain lengthintermediate chain length– weakly acid fastweakly acid fast

• corynebacteriacorynebacteria • shortest chain lengthshortest chain length– not acid fastnot acid fast

Mycobacterium avium complex (MAC)Mycobacterium avium complex (MAC)

1)1) Most common bacterial opportunistic Most common bacterial opportunistic infection (OI) in adults infected with HIV infection (OI) in adults infected with HIV in the in the developeddeveloped world. world.

2)2) Most found in US – Rare in Africa.Most found in US – Rare in Africa.3)3) Annual frequency in AIDS – 10-20%.Annual frequency in AIDS – 10-20%.4)4) Occurs Occurs latelate in HIV infection. Mean CD4+ in HIV infection. Mean CD4+

Count ~ 10-30/Count ~ 10-30/μμLL. (TB occurs early.). (TB occurs early.)5)5) Inhaled or ingested from environment.Inhaled or ingested from environment.6)6) Spreads via lymphatics then Spreads via lymphatics then

hematogenously.hematogenously.7)7) Taken up in reticuloendothelial organs.Taken up in reticuloendothelial organs.

Mycobacterium avium complex (MAC) Mycobacterium avium complex (MAC) Symptoms in the AIDS Patient: Symptoms in the AIDS Patient:

DisseminatedDisseminated GastrointestinalGastrointestinal

Fever Fever Chronic Diarrhea & Chronic Diarrhea & Night Sweats Night Sweats Abdominal PainAbdominal PainWeight LossWeight Loss Malabsorption MalabsorptionMalaiseMalaise Cholestatic Jaundice Cholestatic JaundiceAnemiaAnemiaElevated LFTsElevated LFTs (Alkaline Phosphatase)(Alkaline Phosphatase)

MAC in the MAC in the NonNon-HIV/AIDS Patient:-HIV/AIDS Patient:

1)1) More common as a cause of pulmonary More common as a cause of pulmonary disease in persons born in United States disease in persons born in United States than TB.than TB.

2) Increasing in incidence over the last 20-30 2) Increasing in incidence over the last 20-30 years. years.

3) Progressive pulmonary disease on x-ray 3) Progressive pulmonary disease on x-ray and clinically.and clinically.

4) Sputum culture positive.4) Sputum culture positive.5) Dissemination rare to non-existent. 5) Dissemination rare to non-existent.

Diagnosis of MAC in AIDSDiagnosis of MAC in AIDS Biopsy of the involved reticuloendothelial Biopsy of the involved reticuloendothelial organs with acid fast stain and/or culture.organs with acid fast stain and/or culture.

Blood culture. (85% of Blood culture. (85% of patients with disseminated patients with disseminated MAC are mycobacteremic.)MAC are mycobacteremic.)

EID CDC

CDC/Dr. Edwin P. Ewing, Jr. ←← MACMAC infection of infection of lymph node.lymph node.Acid-fast bacilli Acid-fast bacilli within plump within plump histiocyteshistiocytes.

Colon Biopsy Colon Biopsy MycobacteriumMycobacterium avium – avium – Acid Fast Stain Acid Fast Stain →→

© Dr. Peter Anderson, University of Alabama at Birmingham, Dept of Path.

MycobacteriaMycobacteria

SKIN PATHOGENSSKIN PATHOGENS

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.

NAME OF DISEASE:     Buruli ulcers, Mycoburuli ulcers

Atypical 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 granuloma

Mycobacterium marinum

Contact 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

Swimming pool granuloma: Localized nodular skin inflammation (small reddish raised areas of skin) caused by a bacterium called Mycobacterium marinum

KEYWORDSKEYWORDS• Acid Fast• Ziehl-Neelsen Stain

– 5% H2SO4

• Mycolic acids• M. leprae• Non cultivable• Armadillo, Mouse footpad• Lepromin test• Ridely Jopling

classification Tuberculoid / Lepromatous

• Lab diagnosis –Skin clippings

• Atypical• Runyon groups• Antibiotic

resistance• Opportunistic

infection

• Skin pathogens M.marinum & M. ulcerans

• Buruli ulcer