Microbiology B6 Lecture 15

Front 1

Mycobacteria:

1) What do you stain them with? Why?
2) Why can't you use the usual stain?
3) What color do they stain?
4) Culture? How often? What do colonies look like?
5) Growth rate
6) Respiration
7) Which mycobacteria can't be cultured on bacteriological media?

Back 1

1) Acid fast (Ziehl-Nielssen) - b/c mycolic acid replaces NAM in cell wall peptidoglycan
2) High lipid content of cell wall (60%)
3) Red
4) Lowenstein-Jensen medium (egg based) - take 3 separate cultures at 3 separate times. Colonies look waxy
5) Slow growth rate, isolation up to 8 weeks
6) Aerobic
7) M. leprae

Front 2

Mycobacterium tuberculosis

1) Infected cases globally/USA
2) Incidence globally/USA
3) Prevalence globally/USA
4) Deaths globally/USA
5) Multiple drug resistance globally/USA
6) Worldwide, most common cause of...
7) In 1998, how many cases? Lowest rate since?
8) Who accounted for most of the cases in 1998?
9) Rate of TB highest in what ethnicities?

Back 2

1) 2 billion (33%), 10 million (4%)
2) 10 million, 15,000
3) 50 million, 25,000
4) 2 million, 2,000
5) 15%, 1%
6) Infection-related mortality
7) ~13,000 - 1953.
8) Foreign born persons, 50%
9) Asians (23x whites), Hispanics and blacks (8x whites)

Front 3

Mycobacterium tuberculosis:

1) Virulence factor? Derived from? How do they work?
2) Transmission
3) Susceptibility factors
4) Primary infection - transmission? Immunity? Symptoms? Outcomes?

Back 3

1) a) Coding factor - mycolic acid. Inhibits PMN migration, induces granuloma. Results in serpentine cord formation in cord.
b) Sulfatides - glycolipids. Inhibit phagolysosome formation, allows them to be FACULTATIVE INTRACELLULAR inside macrophages

2) Respiratory - aerosol. Coughing, speaking, sneezing. Most people exposed NOT infected.

3) HEALTH CARE WORKERS, homelessness, overcrowding, HIV, drug use, immigrants, native americans.

4) Aerosol, T-cell immune response. Pulmonary, single focus granuloma. GHON COMPLEX - lung granuloma and mediastinal lymph node that may CALCIFY. Outcome - 1) resolution, patient remains asymptomatic 2) latent infection (dormant) 3) progressive primary infection - can progress in lungs, erode blood vessels, get into bloodstream and disseminate. Possible miliary TB

Front 4

Tuberculosis: progressive primary infection:

1) Main symptoms and what they're characterized by
2) May lead to

Back 4

1) Granuloma formation - (CD4 T cell, Th1), epithelioid cells and giant cells derived from macrophages.

Necrosis (caesation) and cavitation of lung granuloma.

2) Systemic (hematogenous) spread, great imitator, or

MILIARY TB - massive bacterial overload, overwhelming hematogenous spread to other organisms, usually in compromised subjects, high mortality rate.

Front 5

Tuberculosis:

1: Presentation of tuberculosis: ALL SYMPTOMS (5)

2) Diagnosis

3) Therapy

4) DOC

5) Therapy for those who convert to a positive skin test, asymptomatic, clear CXD

6) Vaccine

Back 5

1)

Charlie Has Few Weeks Left
1) persistent, productive COUGH
2) Hemoptysis (bloody sputum)
3) Fever, night sweats
4) Weight loss, loss of appetite
5) Lethargy/weakness/fatigue

May mimic many other disease in other sites, related to sites

2) History, physical exam, x-rays, then PPD skin test, acid fast stain, culture, nucleic acid probe hybridization for species identification

3) Multi drug therapy with at least TWO drugs for several months (to prevent appearance of resistant strains)

4) Primary anti-TB drugs: ISONIAZID. Secondary: amikacin, kanamycin - less effective, more expensive, more toxic

5) Isoniazid daily for 9 months

6) BCG - attenuated strain of M. bovis, variable efficacy, results in positive PPD skin test

Front 6

How does TB meningitis compare to bacterial meningitis caused by S. pnuemoniae?

What is a TB brain abscess called?

What is Pott's disease?

When does oral tuberculosis usually occur?

What is scrofula?

Back 6

Slower onset, gets progressively worse.

Tuberculoma

TB spread to the bone

Secondary to pulmonary TB

Infected, caseating lymph nodes, drains sinuses out through skin

Front 7

Tuberculosis skin tests:

1) What are they

3) Cause what type of reaction?
4) Maximal response in?
5) When do you read?
6) What do you measure?
7) What do you record?
8) TST interpretations (positive, negative)

Back 7

1) Mantoux skin tests:

a) Tuberculin, crude M. tuberculosis antigen

b) **PPD - purified protein derivative - injected intradermally.

3) Delayed hypersensitivity reaction

4) 72 hours

5) 48-72 hours
6) Induration, not erythema
7) Record measurement in mm
8) Positive = previous exposure, current infection, or BCG vaccination. Negative = No prior exposure, active TB in immunodeficient patient (anergy, no Th1 cells left to respond to skin test), pt has overwhelming TB, young children <6 mo.

Front 8

TB two step testing

1) First test positive
2) First test negative
3) Second test positive
4) Second test negative

What is the purpose of this?

Back 8

1) Consider person infected
2) Give second test 1-3 weeks later
3) Consider person infected
4) Consider person uninfected or at baseline

Used for initial baseline for adults who will be retested periodically, determine difference between boosted reaction and reactions due to recent infections

Front 9

Two types of TB resistant strains:

1) MDR-TB
a) Resistant to?
b) % of cases US? Worldwide?
c) Common in?
d) Recommendations?

2) XDR-TB
a) Resistant to?
b) Treatment?
c) # of cases?

Back 9

1) Multi-drug resistant TB
a) Rifampin and isoniazid, with or without resistance to other drugs
b) 1.2% US, 20% worldwide
c) HIV-infected patients
d) At least 4 drugs given concurrently

2) Extensively drug resistant TB
a) All first and second line drugs
b) Extremely diffult
c) 4 cases in US in 2008

Front 10

How to treat a patient with

1) Latent TB

2) Active TB (suspected or known)

Back 10

1) Standard infection control

2) remove area, mask them, assess and refer. Don't treat until declared noninfectious by physician. Urgent dental care in facility w/ airborne infectious isolation, respiratory protection (disposable N-95 respirators)

Front 11

Tuberculosis outcomes, starting with exposure

Back 11

-> 30% infection, 70% nothing
-> 95% PPD+, 5% pulmonary TB
-> 5% reactivate, 95% lifelong containment

Front 12

MOTT

1) What is it?
2) Most common MOTT
3) Reservoir
4) Method of infection?
5) Common in?
6) Presents as?
7) Resistance?
8) How do you treat a patient with MOTT?

Back 12

1) Mycobacterium other than tuberculosis
2) Mycobacterium avium-intracellulare
3) Birds and mammals
4) Opportunistic
5) AIDS patients
6) TB
7) Highly resistant to anti-TB drugs
8) Standard infection control - these are opportunistic, not harmful to other patients

Front 13

Mycobacterium leprae:

1) Causes what disease?
2) Stain with? Shape?
3) Culture?

Back 13

1) Leprosy
2) Acid fast bacillus
3) Cannot culture, isolated following inoculation of armadillos

Front 14

Leprosy

1) Caused by?
2) How many cases worldwide/US?
3) How many new cases/year in US?
4) Mode of transmission?
5) Infectivity?
6) Incubation time?
7) Contagious?
8) Primarily involves which parts of the body?
9) Two forms?
10) DOC?
11) Where treated?
12) Recurrence?

Back 14

1) Mycobacterium leprae
2) ~800,000/6,000
3) ~200
4) Uncertain, probably respiratory, contact with nasal discharge
5) Low infectivity
6) ~5 years
7) Not contagious if on therapy
8) Skin, peripheral nerves, eyes, mucous membranes (nose and throat)
9) Tuberculoid - good DTH (Th1) response to bacterium, few organisms in lesion (paucibacillary, mild disease)

Lepromatous - poor DTH response, many organisms found in lesions (multibacillary), severe, disfiguring disease

10) Multidrug, rifampicin, ofloxacin, minocycline, dapsone. **MOXIFLOXACINE** extremely effective.

11) Outpatients
12) Rare after successful treatment

Front 15

Tuberculoid leprosy:

1) Also known as?
2) Symptoms?

Leprotamous leprosy:

1) Also known as:
2) Symptoms
3) What part of the body commonly involved

Back 15

1) Paucibacillary
2) Few well-circumscribed, hypopigmented skin lesions, nerve involvement with anesthesia of affected skin

1) Multibacillary
2) Numerous hypopigmented skin lesions, ***ORAL LESIONS IN 60%, sensory nerve involvement beginning in extremities (peripheral neuropathy, foot drop), tissue destruction, scarring
3) Face distorted (leonine facies), collapse of bridge of nose