Professor Stewart Cole FRS Chair of Microbial Pathogenesis
Transcript of Professor Stewart Cole FRS Chair of Microbial Pathogenesis
Professor Stewart Cole FRS Chair of Microbial Pathogenesis
Meeting of the ILEP Board & Technical Commission
• 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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• 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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