Professor Stewart Cole FRS Chair of Microbial Pathogenesis

Meeting of the ILEP Board & Technical Commission

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Slide 12 Slide 12

Cole et al. (2001) 2

•  Drug susceptibility testing

•  Molecular epidemiology

•  Non-human sources of transmission

•  Perspectives for leprosy control

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•  Limited DR reported, mainly in patients receiving inadequate therapy

•  Relapse cases usually DS •  DR assessed in vivo by MFP •  Or in vitro by radiometric method •  Both require viable bacilli & are slow, costly

& laborious •  Expertise has disappeared

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•  Known resistance loci: – Rifampicin - rpoB gene (RNA polymerase

subunit β) – Dapsone - folP1 (Dihydropteroate synthase)

– Ofloxacin - gyrA (DNA gyrase)

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•  Operating in 9 leprosy endemic countries: Brazil, China, Columbia, India, Myanmar, Pakistan, Philippines, Viet Nam and Yemen.

•  Standardized technical and operational procedures WHO “Guidelines for Global Surveillance of Drug Resistance in Leprosy” (SEA-GLP-2009.2).

•  10 reference labs: Brazil, France, Japan, Korea, India, Switzerland and USA

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•  PCR amplification of target

•  ABI sequencing of rpoB, folP1 and gyrA loci

•  Biopsies and Slit-skin smear slides

•  No requirement for viability or cold chain

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Ur1-1 (Uruguay)

Ur1-2 (Uruguay)

V2-1 (Venezuela)

V2-2 (Venezuela)

Maeda et. al 2001

ABI-sequence analysis of the RRDR region

of rpoB

85054 (Paris, Martinique)

TCG Ser

TTG Leu

TCG Ser

TCG Ser

TCG Ser

Drug & resistance target

Total number of M. leprae strains analyzed

Mutation in target

Rifampicin (rpoB) 219 0 Dapsone (folP1) 217 2 Ofloxacin (gyrA) 219 0

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Maeda et. al Dec 2001

Ur1-1 Ur1-2 V2-1 V2-2 V2-3

85054 82073

Probe1: shows if sensitive to rifampicin (wild-type)

Probe2: shows if resistant to rifampicin (Ser>Leu mutation)

85054

82073

Ur1-1 Ur1-2 V2-1 V2-2 V2-3

RT-PCR analysis of the RRDR region

of rpoB

ΔR

n

ΔR

n

TTG Leu

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•  Hain GenoType® MTBDRplus Assay

11 •  Similar test available for leprosy

•  MDST is rapid, sensitive, inexpensive and reliable

•  No other methods have equivalent capacity

•  MDST can be implemented at regional level

•  Valuable adjunct to control programmes

•  Must be used for all isolates

•  Combined with strain typing

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•  Provides valuable epidemiological data

•  Fulfills sentinel role

•  Enables technology transfer

•  Builds & maintains capacity

•  Cost effective

•  Important global scientific activity

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