Transmission of Dapsone-Resistant Leprosy Detected by Molecular Epidemiological Approaches

Abstract

Drug resistance surveillance identified six untreated leprosy patients in the Philippines with Mycobacterium leprae folP1 mutations which confer dapsone resistance. Five patients share a village of residence; four who carried the mutation, Thr53Val, were also linked by M. leprae variable-number tandem repeat (VNTR) strain types. In India, folP1 mutations were detected in two relapse patients with a history of dapsone treatment. Mutations were not found in the rifampin target gene rpoB. These findings indicate that dapsone resistance is being transmitted.

Real-Time PCR and High-Resolution Melt Analysis for Rapid Detection of Mycobacterium leprae Drug Resistance Mutations and Strain Types

“…There is only one report for this mutation type (24), which incidentally was detected in the same studied population, i.e., leprosy patients in Cebu, Philippines. The identification of multiple cases with this mutation in our study sample was due to transmission within a closely linked community, as captured and described in greater detail by Li et al by prospective molecular epidemiological approaches (18,30,31). Singh et al recently reported a method based on TaqMan probe assays for rpoB and folP1 (35).…”

“…The gyrA DRDR had not been sequenced. This sequence-based survey detected mutations in folP1 but not in rpoB DRDRs (18). The folP1 mutation types found were a codon 55 mutation (CCC¡CTC) (n ϭ 1) and a codon 53 mutation (ACC¡GTC) (n ϭ 3).…”

“…The clinical skin biopsy samples used in this study were obtained from patients presenting at the Cebu Skin Clinic, Leonard Wood Memorial Leprosy Research Centre, Philippines, as previously described (n ϭ 121) (18,31) and at the Anandaban Hospital, Kathmandu, Nepal (n ϭ 25; collected during 2000 to 2010). The Philippine samples were stored in 70% ethanol at the time of collection.…”

“…Having validated that wild-type and several mutation types in the DRDRs can be identified in reference strains, the real-time HRM-PCR assays were tested on clinical samples. For this, 121 DNA samples extracted from clinical biopsy specimens from Philippine patients that had been analyzed previously by conventional PCR-DNA sequence-based mutation surveillance of folP1 and rpoB DRDRs were selected (18). The gyrA DRDR had not been sequenced.…”

Mycobacterium leprae in Colombia described by SNP7614 in gyrA, two minisatellites and geography

“…Two types of strain typing markers- variable number of tandem repeats (VNTRs) and single nucleotide polymorphisms (SNPs) that provide a range of resolution have been discovered and applied for different epidemiological questions (Groathouse et al, 2004; Zhang et al, 2005; Shin et al, 2000; Kimura et al, 2009; Srisungnam et al, 2009; Monot et al, 2005; Truman et al 2011). These applications include identification of family and community transmission clusters of leprosy and their evolution in geographic space, time and ethnicity (Weng et al, 2011; Sakamuri et al, 2009), the origin and global spread of leprosy (Matsuoka et al, 2006; Monot et al 2005), the surveillance of drug resistance (Maeda et al, 2001; Singh et al, 2011) and detection of clusters of resistant cases ( Li et al, 2011), distinction of relapse from re-infections and mixed infections (da Silva Rocha et al, 2011; Sakamuri et al, 2009; Weng et al, 2011), and for obtaining evidence for zoonosis ( Truman et al, 2011) and ‘reverse zoonosis or anthoponosis’ (Suzuki et al, 2010). …”