MDR TB is tuberculosis caused by strains of Mycobacterium tuberculosis that are resistant to both isoniazid and rifampicin, the most potent anti-TB drugs. In India in 2012, MDR TB accounted for approximately 2.2% of new TB cases and 15% of retreatment cases. Diagnosis requires culture and drug susceptibility testing showing resistance to both isoniazid and rifampicin. Treatment follows WHO DOTS Plus guidelines and involves a regimen of several second-line drugs for 20 months or longer. Adherence to treatment is critical for successful treatment of MDR TB.

1. MDR TB
HARIKRISHNAN. M
2010 MBBS

2. DEFINITION
MDR TB: TB caused by a
strain of M. tuberculosis
that is resistant to both
isoniazid and
rifampicin.

3. Why INH and Rifampin
 Most potent and bactericidal.
 Mono-resistance to one of them can be treated
effectively with a regimen containing the other agent
with very low failure rate (2.5-5%)
 Failure rate when INH + Rifampicin resistant is 44%
in non-HIV and 70% in HIV patients
 Duration required for cure doubles to triples.

4. EPIDEMIOLOGY

5. STATISTICS -INDIA
Estimates of MDR-TB
burden 2012
New
Retreatment
% of TB cases with MDRTB
2.2(1.9-2.6)
15(11-19)
MDR –TB cases among notified pulmonary
21000(18000-25000) 43000 (32000-54000) TB
cases

6. Reported cases of MDR TB 2012
Total
Cases tested for MDR TB
55611
Laboratory confirmed MDR TB cases
16588
Patients started on MDR TB treatment
14143

7. MDR SUSPECT
 Category I failures
 Category II patients who are smear positive at 4
months or later.
 Contacts of MDR cases who are found to be smear
positive.(2009)

8. DIAGNOSIS
 MDR-TB is not clinically distinguishable from drug-
susceptible TB at the outset.
 Signs, symptoms, and radiological findings are
similar initially to drug-susceptible TB.

9.  Sputum culture

DST(Drug Susceptibility Testing) –
definitive diagnosis of drug
resistant TB.
 2 methods
 Phenotypic and Genotypic

10.  Phenotypic method- culturing of M. tuberculosis in
the presence of anti TB drugs to detect growth
(indicating drug resistance) or inhibition of growth
(indicating drug susceptibility)
 Phenotype DST methods are performed as direct or
indirect tests on solid or liquid media.

11.  And among them Indirect
phenotype test is
extensively validated and are currently regarded as
GOLD STANDARD.

12.  Genotypic method- targets specific molecular
mutations associated with resistance against
individual drugs.
 Moleular testing allows rapid detection of resistance
to rifampicin( alone or in combination with
isoniazid). It provides DST results within one day.
 Catridge based nucleic acid amplification test(NAAT)
–very high sensitivity.

13. TREATMENT
 Difficult.
 WHO recommends DOTS PLUS guidelines initiated
by PMDT (Programmatic Management of Drug
Resistant TB)
 After diagnosis treatment of MDR TB is initiated at
designated DOTS Plus sites which are established in
tertiary care centres ( like medical colleges, large
speciality hospitals).

14. DOTS PLUS
Treatment regime :
6 (9) months - kanamycin
ofloxacin
ethionamide
cycloserine
pyrazinamide
ethambutol

15. 18 months –Ofloxacin
Ethionamide
cycloserine
ethambutol

16.  Follow up:
 Smear examination should be conducted monthly
during intensive phase and atleast quarterly during
continuation phase.
 Culture examination should be done atleast at 4,6,12,
18 and 24 months of treatment.

17.  Treatment adherence : patient and family members
counselled prior to treatment initiation and during
follow up visits.
 Efforts should be made to administer treatment
under DOTS over entire period of treatment.

18.  Documentation of treatment : Systemic record of
treatment, regimen, doses, duration, side effects,
investigation results and treatment outcome for all
patients initiated on second line treatment should be
maintained.

19. 2009 DOTS PLUS policy
 Defn of MDR suspect revised to include ‘contacts of
MDR cases who are found to be smear positive’
besides Cat I failures and Cat II patients who are
smear positive at 4 months or later.
 The existing exclusion criteria for MDR suspects i.e.
age <15 years and history of intake of 2nd line drugs
for more than 1 month in the past has been
withdrawn. A new weight band (16-25 kgs) has been
added for the treatment of pediatric MDR patients.

20.  Inorder to make the Cat IV regimen more effective it
has been decided to replace Ofloxacin with
Levofloxacin.
 Guidelines for management of MDR patients with
pregnancy has been finalised.

21. THANK YOU