Lecture 10 - Mycobacteria and spirochaetes

Question 1

What are the types of mycobacterium species?

Answer 1

Mycobacterium tubercolosis

MOTT (Mycobacterium Other Than Tubercolosis) / NTM (Non Tubercolosis Mycobacteria)

Mycobacterium leprae

Question 2

What are the types of spirochaetes?

Answer 2

Genus Treponema

Genus Borrelia

Genus Leptospira

Genus Spirillum

Question 3

What are the characteristics of Mycobacterium?

Answer 3

Very slow growers

Very fastidious growth requirements

Not detectable on Gram stain

Waxy mycolic acid in cell envelop making them resistant to drying

Question 4

Why are mycobacterium so good at surviving for long periods of time?

Answer 4

Due to the presence of mycolic acid in their capsules

Question 5

What type of stains work on mycobacterium?

Answer 5

Carbol fuchsin stain

Ziehl-Neelson stain

AFBs appear red against blue background

Question 6

What type of stains work on mycobacterium?

Answer 6

Carbol fuchsin stain

Ziehl-Neelson stain

AFBs appear red against blue background

Question 7

What are Acid Fast Bacteria (AFBs)?

Answer 7

They are bacteria that stain carbol fuchsin the stain cannot be removed with acid-alcohol

Question 8

What is a Ziehl-Neelson stain?

Answer 8

A blue counter stain which contrasts with AFB

Question 9

How are mycobacteria classified?

Answer 9

Using species complexes

Question 10

What are the related species to the mycobacterium tubercolosis complex?

Answer 10

Mycobacterium tubercolosis

Mycobacterium Bovis

Mycobacterium bovis BCG (attenuated strain of mycobacterium bovis used in vaccines)

Mycobacterium africanum

Question 11

How much of the population is infected by TB?

Answer 11

1/4 to 1/3 of the world’ds population

Question 12

What kind of people have TB?

Answer 12

The urban homeless

Immigrants

AIDS patients

Question 13

Which countries have TB most?

Answer 13

Developing countries

Question 14

How is TB transmitted?

Answer 14

Through inhalation and spread by people with active pulmonary infection

Question 15

How does pulmonary TB transfer from one person to another?

Answer 15

Open case of pulmonary TB occurs from lesions in the lungs opening into the airways and aerosol droplets get transferred between people

Question 16

What happens after inhalation of TB?

Answer 16

Sometimes Bacteria is elminated by immune system

Other times the bacteria survive in granuloma of lung.(90 - 95% remain in granuloma whereas 5 - 10% are reactivated and cause disease in people in >50% in less than 2 years and in another 50% in more than 2 years.

Question 17

What is pott’s disease?

Answer 17

Infection of vertebral body causing collapse of vertebrae and a hump appearance

Question 18

What potential sites can TB be seen on?

Answer 18

Foci of infection could be focused in lungs as primary site of infection and then disease can move to distant organs (eg meninges, brain, myocardium, pericardium, bone, kidneys, lymphorectal tissue)

Question 19

What can mycobacteria other than TB do?

Answer 19

Range of pulmonary diseases or disseminated disease in AIDS patients

lymphadenitis

chronic skin and soft tissue lesions

Question 20

How is leprosy acquired?

Answer 20

Inhalation route or direct contact

Question 21

How likely is it for mycobacterium leprae to cause disease?

Answer 21

Majority of infections are overcome by the immune system producing no symptoms

Question 22

What is the response of the body to the leprosy pathogen caused by?

Answer 22

Host’s immune response

Question 23

What are the types of leprosy responses?

Answer 23

Weak as in Lepromatous leprosy (weak CMI response)

Strong Tuberculoid leprosy (strong CMI response)

Question 24

Which tissue is typically affected by leprosy?

Answer 24

skin

upper respiratory tract

peripheral nerves

testes

Question 25

What are the defining features of tubercoloid leprosy?

Answer 25

Hypopigmented macules with raised red borders and the center lacks sensation Damage to large nerves resulting in complete sensory loss in nerve's distribution

Question 26

What are the features of lepromatous leprosy?

Answer 26

Nodules, plaques, and generally thickened dermis Heavy infiltration of upper respiratory tract particularly nasal with congestion and nosebleeds as well as destruction of nasal cartilage. Destruction of bone and ear cartilage Diffuse nerve involvement; sensory loss to hands and feet Testicular invasion and impaired function; low testosterone

Question 27

What are the types of spirochaetes?

Answer 27

Treponema Borrelia Leptospira Spirillum

Question 28

What is the spirochaete shape?

Answer 28

Spiral

Question 29

Which treponema species are pathogenic to humans?

Answer 29

Treponema pallidum (syphilis) Treponema pertenue (yaws) Treponema endemicum (bejel) Treponema carateum (pinta)

Question 30

What does syphilis do?

Answer 30

Chronic disease that is sexually transmitted

Question 31

What are the stages of syphilis?

Answer 31

primary secondary teriary quaternary

Question 32

What are the symptoms of primary syphilis?

Answer 32

Chancre at inoculation site with raised edges Painless Raised firm edges

Question 33

is syphilis limited to genital sites?

Answer 33

No it can happen to non-genital sites

Question 34

What are the symptoms of secondary syphilis?

Answer 34

Fever Fatigue Myalgia Skin rashes Mucous patches Condyloma lata (plaque like lesions) meningitis can or may not manifest

Question 35

What are the stages of latent syphilis?

Answer 35

Early latent syphilis is asymptomatic with recurrences of secondary syphilis lesions Late latent syphilis is asymptomatic and can cause tertiary syphilis

Question 36

What are the forms of tertiary syphilis?

Answer 36

Gummatous Cardiovascular Neurosyphilis

Question 37

What is gummatous syphilis?

Answer 37

granulomatous lesions called gummas in skin and bone

Question 38

What happens over time with gummatous lesions?

Answer 38

Destruction of surrounding tissue by expanding mass effect In bone gumma produce pressure and deformity

Question 39

What are the cardiovascular effects of tertiary syphilis?

Answer 39

Syphilic aortitis causing inflammation of small vessels feeding the aorta leading to aneurysm or dilation of aortic valve ring causing insufficiency of the valve Coronary artery stenosis Myocardial infarction

Question 40

What are the symptoms of neurosyphilis?

Answer 40

Meningovascular syphilis causing aseptic meningitis, cranial nerve damage, and blindness/deafness Parenchymatous syphilis Neuropsychiatric disturbance Posterior spinal cord damage and inability to receive sensory peripheries

Question 41

What are the symptoms of parenchymatous syphilis?

Answer 41

Neuropsychiatric disturbance and posterior spinal column damage "general paresis of the insane" Inability to receive sensory input from peripheries "tabes dorsalis" (slapping feet gait)

Question 42

How does syphilis affect neonates?

Answer 42

50% die and wide variety of symptoms in survivors

Question 43

What are the symptoms in neonatal survivors of syphilis?

Answer 43

Hutchinson's teeth Saddle nose rashes

Question 44

What is yaws?

Answer 44

Chronic non-venereal disease caused by Treponema pertenue

Question 45

What does non-venereal mean?

Answer 45

Not related to sexual intercourse

Question 46

What does yaws affect?

Answer 46

Mainly skin and bone

Question 47

Where is yaws typically seen?

Answer 47

Tropical areas in underprivileged commnities

Question 48

How is treponema pertenue transmitted between people?

Answer 48

spread by contact

Question 49

What is bejel?

Answer 49

Non-venereal syphilis like disease caused by treponema endemicum

Question 50

Where is bejel typically seen?

Answer 50

In the tropics and acquired by children in conditions of poor hygiene

Question 51

What is pinta?

Answer 51

Ulcerative or papular depigmenting skin disease caused by the bacteria; treponema carateum

Question 52

How are borrelia species transmitted?

Answer 52

Insects

Question 53

What are the species of borrelia relevant to us?

Answer 53

Borrelia recurrentis (epidemic louse-borne relapsing fever) Borrelia burgdorferi (lyme disease) Other Borrelia species (endemic tick-borne relapsing fever)

Question 54

How do humans get leptospira infections?

Answer 54

Contact with domestic and wild animal tissue, urine, soil, mud or water containing urine

Question 55

What are the symptoms of leptospira interrogans infection?

Answer 55

Spectrum of symptoms Can cause flu like symptoms such as: sudden onset fever, malaise, severe headache, lowback+calf pain, photophobia Or it can cause Weil's disease which appears as jaundice, renal failure, obliguria, haemorrhage, and shock

Question 56

How is spirillum minor transmitted between people?

Answer 56

Rat bites (uncommon infection)