Tuberculosis Paper Summary 2021

Question 1

Important among certain high risks groups

Answer 1

Aboriginal people
•Foreign-born residents from countries
with high prevalence of TB
•Disadvantaged inner-city populations
•HIV-infected people

Question 2

1995

Answer 2

incidence rate was 6.5 per 100,000
•Currently (2017) 1,800 cases of active TB
reported annually

Question 3

In BC in 2000

Answer 3

285 cases reported

Question 4

Tuberculosis

Answer 4

Mycobacterium tuberculosis

(Bacteria; High G+C Gram
+; Actinobacteria)

Question 5

What is the widely accepted hypothesis that
explains the persistence of tuberculosis in
developed countries?

Answer 5

Hypothesis: Foreign-born people are infected in their
country of origin and then
• primary disease develops shortly after immigration
• people remain at risk for reactivated disease for the rest of
their lives

Question 6

People with clustered isolates =

Answer 6

same transmission

chain

Question 7

Molecular biology allowed the development of
what to distinguish between different
M. tuberculosis isolates

Answer 7

fingerprinting method

Question 8

People with unique isolate =

Answer 8

reactivated cases (origin
of isolate in a foreign country)

Question 9

2 studies in 2002

Answer 9

New York and Denmark

Question 10

New York

Answer 10

people born outside USA much less likely
to be in cluster group (new transmission chain)
But people less than 10 years in USA and not
HIV positive: half have clustered isolates (new
infections).

Question 11

Denmark

Answer 11

55% Somali immigrants were clustered,
But unclear if disease acquired in Somalia and
transmitted in Denmark or being transmitted within the
Somali community in Denmark.

Question 12

What about Greater Vancouver?

Answer 12

Hernandez-Garduno et al. 2002. CMAJ 167:349-345.

Combination of conventional epidemiology with DNA
fingerprinting of M. tuberculosis.

Determine predictors associated with being in a cluster in order to better understand transmission of
tuberculosis in Greater Vancouver.

Question 13

M. tuberculosis identified by

Answer 13

y biochemical test and RNA

hybridization.

Question 14

DNA fingerprinting by RFLP using…

Answer 14

insertion sequence IS

6110 as a probe.

Question 15

when do you use spolingotyping?

Answer 15

Use Spoligotyping if isolates < 6 bands

Question 16

Divided sample into two groups

Answer 16

Divided sample into two groups
Clustered isolates (isolates with
identical band patterns)
Non-clustered isolates (unique band
patterns)

Question 17

Stat tests

Answer 17

Chi-square, Fisher’s exact test for univariate
analysis to assess risk factors.

Predictors significantly associated with
clustering included in multivariate logistic regression
model.

Question 18

Results

Answer 18

806 cases
137 into 46 clusters (infer transmission chain)
656 non clustered (not part of transmission chain)

Question 19

Strongest predictor of clustering:

Answer 19

1.Canadian-born aboriginal vs foreign born (adjusted OR 6.0)
2. Canadian-born non-aboriginal vs foreign born (adjusted OR
3.6)
3. Injection drug user vs patients who did not inject drugs (OR
3.0)
4. Patients with a prior history of tuberculosis less likely to be
part of a cluster than patients with no history of
tuberculosis (adjusted OR 0.3)

Question 20

Source of transmission chain more likely…

Answer 20

from inner city aboriginal

groups

Question 21

Not predictors of clustering are

Answer 21

HIV-HIV seropositivity

Antibiotic resistance

Question 22

odd ratio

Answer 22

Odd Ratio

Relation between obs/expected (total #)

Question 23

who play an important role in
the transmission of tuberculosis in Greater
Vancouver

Answer 23

Younger Aboriginal people

Question 24

who play an

important role in the transmission of TB in GV.

Answer 24

Above 60 years-old, non-Aboriginal people

Question 25

Aboriginal people in
Canada have a gene deletion for what which
may predispose them to acquire TB.

Answer 25

NRAMP1