Genesis of drug resistance in Tuberculosis in South Africa

Rob Warren

vv

GCCGACTGTTGGCGCTGG CGGCTGACAACCGCGACC

rpoB gene

109 bacteria

Rifampicin Rifampicin

Spontaneous evolution of drug resistance

Number of MDR-TB cases in 2013

WHO Global Tuberculosis Report 2014

MDR-TB = resistance to isoniazid and rifampicin

Number of Patients with confirmed XDR-TB 2013

WHO Global Tuberculosis Report 2014

XDR-TB = MDR-TB plus resistance aminoglycoside and fluoroquinolone

MDR-TB Treatment outcome in Africa

40%

WHO Global Tuberculosis Report 2014

Treatment guidelines 2002

Ofloxacin Kanamycin Ethambutol

Pyrazinamide Ethionamide

New Case

Retreatment Case

Isoniazid Rifampicin

Ethambutol Pyrazinamide

Treatment failure

DST

DST

Standardized MDR-TB treatment

Amplification of Resistance in MDR-TB

Mphahlele et al Unpublished data

48 MDR-TB cases enrolled

Standardized MDR-TB treatment

Different strain during treatment

n=12 (25%)

Same strain during treatment

n=36 (75%)

9 (75%) gained additional resistance

13 (36%) gained additional resistance

46%

Louw,G.E., Warren,R.M., Donald,P.R., Murray,M.B., Bosman,M., van Helden,P.D., Young,D.B., and Victor,T.C. 2006. Frequency and implications of pyrazinamide resistance in managing previously treated tuberculosis patients. Int.J.Tuberc.Lung Dis. 10:802-807.

Mphahlele M, Syre H, Valvatne H, Stavrum R, Mannsåker T, Muthivhi T, Weyer K, Fourie PB, Grewal HM. Pyrazinamide resistance among South African multi-drug resistant Mycobacterium tuberculosis isolates. J Clin Microbiol. 2008 Aug 27.

52% of MDR-TB isolates showed resistance to PZA

Weakened standardized MDR-TB treatment

Johnson,R., Jordaan,A.M., Pretorius,L., Engelke,E., van der,S.G., Kewley,C., Bosman,M., van Helden,P.D., Warren,R., and Victor,T.C. 2006. Ethambutol resistance testing by mutation detection. Int.J.Tuberc.Lung Dis. 10:68-73.

Pyrazinamide Ethambutol

Hoek KG, Schaaf HS, Gey van Pittius NC, van Helden PD, Warren RM. Resistance to pyrazinamide and ethambutol compromises MDR/XDR-TB treatment. S Afr Med J. 2009 Nov;99(11):785-7.

>50% of MDR-TB isolates showed mutations conferring EMB resistance

Standardized MDR-TB

Treatment

Ofloxacin Kanamycin Ethambutol

Pyrazinamide Ethionamide

Muller, B., E. M. Streicher, K. G. Hoek, M. Tait, A. Trollip, M. E. Bosman, G. J. Coetzee, E. M. Chabula-Nxiweni, E. Hoosain, N. C. Gey van Pittius, T. C. Victor, P. D. van Helden, and R. M. Warren. 2011. inhA promoter mutations: a gateway to extensively drug-resistant tuberculosis in South Africa? Int.J.Tuberc.Lung Dis. 15:344-351.

Cross-resistance between isoniazid and ethionamide via inhA mutations

48%

Standardized MDR-TB

Treatment

Ofloxacin Kanamycin Ethambutol

Pyrazinamide Ethionamide

0%

20%

40%

60%

80%

100%

DS DR

MDR s.s.

pre-XDRXDR

0%

20%

40%

60%

80%

100%

DS DR

MDR s.s.

pre-XDRXDR

0%

20%

40%

60%

80%

100%

DS DR

MDR s.s.

pre-XDRXDR

Western Cape

KwaZulu- Natal

Eastern Cape

Programmatic Selection

Muller, B., V. N. Chihota, M. Pillay, M. Klopper, E. M. Streicher, G. Coetzee, A. Trollip, C. Hayes, M. E. Bosman, N. C. Gey van Pittius, T. C. Victor, S. Gagneux, P. D. van Helden, and R. M. Warren. 2013. Programmatically selected multidrug-resistant strains drive the emergence of extensively drug-resistant tuberculosis in South Africa. PLoS.ONE. 8:e70919.

Immigration

Type 1: katG315 ACC, rrs513 CAC, inhA 17, embB306 ATA, pncA ins172G, rpoB 516GTC, rrs1401G Type 2: katG315 ACC, rrs513 CAC, inhA 15, embB306 ATC, pncA14 GCG, rpoB 531 TTG, rrs1401G

XDR-TB Treatment outcomes

Pietersen, E., E. Ignatius, E. M. Streicher, B. Mastrapa, X. Padanilam, A. Pooran, M. Badri, M. Lesosky, H. P. van, F. A. Sirgel, R. Warren, and K. Dheda. 2014. Long-term outcomes of patients with extensively drug-resistant tuberculosis in South Africa: a cohort study. Lancet .

Discharge into the Community

Pietersen, E., E. Ignatius, E. M. Streicher, B. Mastrapa, X. Padanilam, A. Pooran, M. Badri, M. Lesosky, H. P. van, F. A. Sirgel, R. Warren, and K. Dheda. 2014. Long-term outcomes of patients with extensively drug-resistant tuberculosis in South Africa: a cohort study. Lancet .

RR-TB patients must be started on treatment within 5 days

MDR-TB regimen for 18 – 24 months

On confirmation of MDR-TB the laboratory should conduct second-line DST routinely.

New TB diagnosis algorithm

Impact of New TB diagnosis algorithm

Time to second-line resistance test result

54 days (IQ range 27-259)

Drug resistant Patients with second-line results (%), N=451

Kanamycina only 3 (0.7) Ethionamide only 206 (45.7) Fluoroquinoloneb only 13 (2.9) Kanamycin + Ethionamide 25 (5.5) Kanamycin + Fluoroquinolone

4 (0.9)

Ethionamide + Fluoroquinolone

14 (3.1)

Kanamycin + Ethionamide + FQ

28 (6.2)

Any additional resistance 293 (65.0) Pre-XDR 55 (12.2) XDR 32 (7.1)

Second-line resistance profiles associated with rifampicin resistance

Proportion of patients with resistance to greater than 2 second-line drugs

47%

TAKE HOME MESSAGE

• Treating blindly leads to amplification of resistance • Surveillance is essential to guide policy • Treatment outcomes for M(X)DR-TB are poor • Nearly half of patients diagnosed with RIF resistant

MTB by Xpert also have resistance to at least two additional MDRTB drugs

• Culture based diagnostic delay treatment decisions by up to 8 weeks possible promoting amplification of resistance

• Rapid molecular based diagnostic methods are desperately needed

Thank You Karen Jacobson

Borna Muller

Gail Louw

Kim Hoek

Violet Chihota

Matsie Mphahlele

Marinus Barnard

Elize Pietersen

The “Mycobactomics” Group