Leprosy Resistance Research Articles

Implications of drug resistance in leprosy: disease course, reactions and the use of novel drugs.

Leprosy remains a significant neglected tropical disease despite the goal of elimination having been achieved in various endemic nations over the past two decades. Reactional episodes complicate the disease course, resulting in deformities and disability. The main aim of treatment is to kill Mycobacterium leprae and decrease the bacterial load, which could help prevent further bacilli transmission. A major concern in breaking the chain of transmission and possibly for recurrent reactions is the roleof drug-resistant bacilli. Though some data is available on the background prevalence of drug resistance in leprosy, there is a paucity of studies that look for resistance specifically in leprosy reactions. Administration of long-term steroids or immunosuppressants for chronic and recurrent responses in the presence of drug resistance has the twin effect of perpetuating the multiplication of resistant bacilli and encouraging the dissemination of leprosy. The increasing trend of prescribing second-line drugs for leprosy or type 2 reactions without prior assessment of drug resistance can potentially precipitate a severe public health problem as this can promote the development of resistance to second-line drugs as well. A comprehensive multicenter study, including drug resistance surveillance testing in cases of reactions, is necessary, along with the current measures to stop the spread of leprosy. Here, we have detailed the history of drug resistance in leprosy, given pointers on when to suspect drug resistance, described the role of resistance in reactions, methods of resistance testing, and the management of resistant cases with second-line therapy.

High frequency of ofloxacin resistance patterns of Mycobacterium leprae from India: An indication to revisit second line anti-leprosy treatment regimen

Drug resistance in leprosy is an emerging concern, leading to treatment failures, recurrences, and potential spread of resistant Mycobacterium leprae in the community. In this study, we aimed to assess drug resistance prevalence and patterns amongst leprosy patients at a tertiary care referral hospital in India. Mutations in drug resistance determining regions for dapsone, rifampicin, and ofloxacin of the M. leprae genome in DNA extracted from skin biopsies of 136 leprosy patients (treatment-naive=67, with persistent skin lesions=35, with recurrence=34) were analysed by polymerase chain reaction followed by Sanger sequencing. Wild-type strain (Thai-53) was used as a reference strain. Resistance mutations were identified in a total of 23 patients, constituting 16.9% of the cohort. Within this subset of 23 cases, resistance to ofloxacin was observed in 17 individuals (12.5%), while resistance to both dapsone and rifampicin was detected in three patients each (2.2% for both). The occurrence of ofloxacin resistance showed minimal disparity between recurrent and treatment-naive cases, at 17.6% and 16.4%, respectively. Dapsone resistance emerged in two treatment-naive cases and one case with persistent skin lesions. Notably, none of the treatment-naive cases or those with recurrence/relapse exhibited rifampicin resistance. Subsequently, no statistically significant correlation was identified between other clinical variables and the presence of antimicrobial resistance. The occurrence of resistance to the current multidrug therapy regimen (specifically dapsone and rifampicin) and to ofloxacin, a secondary antileprosy medication in M. leprae, represents a concerning scenario. This calls for an expansion towards bactericidal drug options and the establishment of robust surveillance for drug resistance in countries burdened with high leprosy rates. Moreover, the introduction of stringent antimicrobial stewardship initiatives is imperative. As a single centre study, it represents a limited, cross-sectional view of the real situation in the field.

Do steroids cause drug resistance in leprosy?

Do steroids cause drug resistance in leprosy?

Comparison between lymecycline with multidrug therapy and standard multidrug regimen (WHO-MDT) in the treatment of multibacillary leprosy patients: a retrospective cohort study.

Hansen's disease or leprosy is a chronic, infectious disease that has locally and globally afflicted all populations. Despite standard treatment with multidrug therapy (WHO-MDT), the incidence of drug resistance has been an increasingly prevalent global problem in leprosy management. This study compared the effectiveness between lymecycline with WHO-MDT and standard WHO-MDT in leprosy treatment. The research is a retrospective cohort study at a tertiary hospital from January 2011 to July 2021. Pre- and post-treatment bacillary index, presence of new lesions, nerve function impairment, and leprosy reactions were obtained through chart review. The results showed a significant difference in bacteriological index (BI) in both groups at the end of the treatment. However, a higher reduction in BI was noted for the lymecycline group. For the group that took WHO-MDT alone, BI decreased by 0.7 (P < 0.001) whereas patients who took lymecycline and WHO-MDT had a BI difference of 3 (P < 0.001) upon completion of treatment. A significant decrease in the recurrence of lesions (P = 0.006) and nerve function impairment (P = 0.038) was also noted in the lymecycline group whereas there was no significant difference in leprosy reactions between the two groups. Lymecycline 600 mg daily for 3 months can be used as an adjunct in cases of leprosy resistance and treatment failure among multibacillary patients. Lymecycline significantly reduced bacillary index, recurrence of skin lesions, and nerve function impairment through its possible immunomodulatory, antiapoptotic, and neuroprotective effects.

Diagnosis of Leprosy: Current Updates and Future Directions

Leprosy is a chronic infectious granulomatous disorder caused by Mycobacterium leprae, chiefly affecting skin and peripheral nerves. It is the only known bacteria to infect nerves. Clinical diagnosis of leprosy is made when any of the three cardinal signs defined by the World Health Organisation is present. However, leprosy has varied presentations necessitating laboratory diagnostic methods for diagnosis as well as treatment initiation and monitoring. Slit-skin smears and histopathology form the basic diagnostics of maximum utility, while neurological studies, cytology and imaging have significant specific roles. Novel molecular and serological tests are of value in the diagnosis of early, indeterminate, and paucibacillary leprosy, and for screening of asymptomatic contacts. Molecular methods have in addition found an important place in diagnosis of drug resistance in leprosy.

Molecular detection of drug resistance in clinical specimens of leprosy patients from a tertiary care leprosy centre in South India

Background Leprosy is one of the neglected tropical diseases (NTD) experiencing relative stagnancy in the global number of new cases. Objective This study aims to find the proportion of antimicrobial resistance in the clinical specimens of leprosy patients attending a tertiary care leprosy Institute in South India. Materials and methods Skin biopsy specimens (31 Nos) were tested by Polymerase chain reaction (PCR) for identification of M. leprae, and PCR followed by DNA sequencing for antimicrobial resistance (AMR) detection. Results All 31 specimens tested for M. leprae identification were positive. Resistance to dapsone was 6.5%, while rifampicin and ofloxacin showed 100% sensitivity. Conclusion This study warrants the need for a vigilant surveillance mechanism to monitor the trend of antimicrobial resistance in leprosy.

Repurposing Drugs to Combat Drug Resistance in Leprosy: A Review of Opportunities.

Leprosy is caused by extremely slow-growing and uncultivated mycobacterial pathogens, namely Mycobacterium leprae and M. lepromatosis. Nearly 95% of the new cases of leprosy recorded globally are found in India, Brazil, and 20 other priority countries (WHO, 2019), of which nearly two-third of the cases are reported in India alone. Currently, leprosy is treated with dapsone, rifampicin, and clofazimine, also known as multi-drug therapy (MDT), as per the recommendations of WHO since 1981. Still, the number of new leprosy cases recorded globally has remained constant in last one-decade, and resistance to multiple drugs has been documented in various parts of the world, even though relapses are rare in patients treated with MDT. Antimicrobial resistance testing against M. leprae or the evaluation of the anti-leprosy activity of new drugs remains a challenge as leprosy bacilli cannot grow in vitro. Besides, developing a new drug against leprosy through conventional drug development process is not economically attractive or viable for pharma companies. Therefore, a promising alternative is the repurposing of existing drugs/approved medications or their derivatives for assessing their anti-leprosy potential. It is an efficient method to identify novel medicinal and therapeutic properties of approved drug molecules. Any combinatorial chemotherapy that combines these repurposed drugs with the existing first-line (MDT) and second-line drugs could improve the bactericidal and synergistic effects against these notorious bacteria and can help in achieving the much-cherished goal of "leprosy-free world". This review highlights novel opportunities for drug repurposing to combat resistance to current therapeutic approaches.

Sensitivity of different DNA extraction methods and PCR to detect resistance in patients with leprosy stratified by the bacilloscopic index

IntroductionAntimicrobial resistance in leprosy is an emerging problem, and the quantitative impact of low bacilloscopic indexes (BIs) on the sensitivity of molecular tests is unknown. We aimed to evaluate the sensitivity of gene sequencing for the detection of mutations related to antimicrobial resistance in Mycobacterium leprae in patients with low BIs using an analytical model. MethodsPatients with leprosy were included and divided into two groups depending on their BIs (≥ 2+ and < 2+). The sensitivities of the two DNA extraction methods were compared after amplifying and sequencing the repetitive element (RLEP), folP1, rpoB and gyrA in M. leprae. ResultsWe included 56 patients with leprosy: 35 had BIs less than 2+ (22 had negative slit-skin smear [SSS] results) and 21 patients had BIs greater than or equal to 2+. The sensitivity of the amplification of the RLEP target and the gene sequencing of folP1, rpoB and gyrA was 50 to 70% lower in patients with a BI less than 2+ and was significantly reduced in patients with lower BIs for all targets (p < 0.001). One patient had a mutation in the folP1 gene, and 14 patients had mutations in the gyrA gene, but no mutations related to antimicrobial resistance were found. ConclusionsWe can conclude that the sensitivity of molecular tests is directly related to the BI, but these tests can still detect up to 20% of the targets in patients with BIs < 2+. New strategies to improve the sensitivity for detecting antimicrobial resistance in leprosy patients and reasonable clinical criteria for follow-up and the introduction of alternative treatments must be developed.

Potential approaches for the diagnosis and treatment of drug-resistant leprosy

Leprosy, a chronic human disease with potentially debilitating neurological consequences, results from infection with Mycobacterium leprae, which is still a major health problem in several countries of Asia, Latin America, and Africa. With the mass campaigns, using multidrug therapy, the prevalence of leprosy has come down drastically worldwide. Antimicrobial resistance (AMR) is an important consideration in the management of leprosy. Unfortunately, quinolone-resistant strains of Mycobacterium leprae have also been reported in several countries, probably due to the extensive use of quinolones for treating several types of infections. To meet the challenge of containing the disease and being able to respond to an increase in circulation of drug-resistant strains, it is essential to assess drug-sensitivity patterns globally, as well as to monitor resistance among both new and retreatment cases. However, these studies highlight the need for increased vigilance to AMR. In this study, we thoroughly reviewed the molecular methods used to detect drug resistance in leprosy. We can infer that our article assessing strategies less complex than multifunction peripheral and genome sequencing are promising choices for the testing of AMR in leprosy patients. Furthermore, our analysis recommends that the extent of safe cases has not essentially expanded in late many years.

The genetic determinants of &lt;i&gt;Mycobacterium leprae&lt;/i&gt; resistance to antimicrobial drugs

The review is devoted to the appearance of resistance of a slowly developing disease leprosy to antimicrobial therapy (AMP), primarily recommended by the World Health Organization. The main danger of drug resistant leprosy is in the difficulty of identifying, since the causative agent of the disease is not cultivated on artificial media, and the methods for diagnosing drug resistance that are currently used take a long time. The drug resistance of the Mycobacterium leprae strain even to individual components of combination drug therapy result to the development of symptoms of the disease despite undergo anti-leprosy therapy, which in turn can cause the patient to become disabled. Currently, in the Russian Federation, there is no approved test for detecting Mycobacterium leprae DNA, and the determination of genetic determinants of resistance is carried out by sequencing genome regions determined by WHO recommendations: small gyrA, folP and rpoB genes loci. At the same time, modern studies in endemic regions reveal an increased level of Mycobacterium leprae strains resistant to individual components of combined drug therapy. The use of next generation sequencing (NGS) has made it possible to identify additional genetic determinants of leprosy resistance to the components of combination drug therapy. The current situation is relevant to antimicrobal drug resistance surveillance by using of quick identification systems for most frequent genetic resistance determinants of Mycobacterium leprae. The literature search was carried out using keywords in the Scopus, PubMed and RSCI databases.

Nanoliposomal Topical Formulation for Increasing Safety and Combating Microbial Drug Resistance in Leprosy

Nanoliposomes were prepared using solvent injection method and topical spray using simple dispersion method. The particle size and % Entrapment Efficiency were found 18.01 ± 0.21 nm and 87.71 ± 0.12% respectively. TEM studies showed that the particles were in spherical shape. Drying time, volume per spray, area of film and dose uniformity were found to be 280 ± 0.002 sec, 0.16± 0.021 ml, 155.57 ± 0.012 cm2 and 0.15± 0.0012 ml respectively which showed good spraying conditions on the affected area. Stability study shows that dapsone and chaulmoogra oil loaded nanoliposomal topical spray was stable at accelerated condition up to 1 month. The present investigation provides a safe approach by improving the outer membrane permeability to combat microbial drug resistance and increasing safety in leprosy treatment.

Susceptibility and resistance in leprosy: Studies in the mouse model.

Leprosy is a chronic granulomatous infectious disease caused by the pathogen, Mycobacterium leprae, and the more recently discovered, M. lepromatosis. Described in 1873, M. leprae was among the first microorganisms to be proposed as a cause of a human infectious disease. As an obligate intracellular bacterium, it has still not thus far been reproducibly cultivated in axenic medium or cell cultures. Shepard's mouse footpad assay, therefore, was truly a breakthrough in leprosy research. The generation of immunosuppressed and genetically engineered mice, along with advances in molecular and cellular techniques, has since offered more tools for the study of the M. leprae–induced granuloma. While far from perfect, these new mouse models have provided insights into the immunoregulatory mechanisms responsible for the spectrum of this complex disease.

A systematic review and meta-analysis of studies on the diagnostic accuracy and screening of tests to detect antimicrobial resistance in leprosy

Although multidrug therapy is considered an effective treatment for leprosy, antimicrobial resistance is a serious concern. We performed a systematic review of studies on the diagnostic accuracy and screening of tests for antimicrobial resistance in leprosy. This review was registered in PROSPERO (CRD42020177958). In April 2020, we searched for studies in the PubMed, EMBASE, Web of Science, Scopus, Scielo, and LILACS databases. A random effects regression model was used for the meta-analysis. We included 129 studies. Molecular tests for dapsone resistance had a sensitivity of 78.8% (95% confidence interval [CI] = 65.6–87.9) and a specificity of 97.0% (95% CI = 94.0–98.6). Molecular tests for rifampicin resistance had a sensitivity and specificity of 88.7% (95% CI = 80.0–93.9) and 97.3% (95% CI = 94.3–98.8), respectively. Molecular tests for ofloxacin resistance had a sensitivity and specificity of 80.9% (95% CI = 60.1–92.3) and 96.1% (95% CI = 90.2–98.5), respectively. In recent decades, no increase in the resistance proportion was detected. However, the growing number of resistant cases is still a clinical concern.

Adding MASP1 to the lectin pathway-Leprosy association puzzle: Hints from gene polymorphisms and protein levels.

Deposition of complement factors on Mycobacterium leprae may enhance phagocytosis. Such deposition may occur through the lectin pathway of complement. Three proteins of the lectin pathway are produced from the gene MASP1: Mannan-binding lectin-associated serine protease 1 (MASP-1) and MASP-3 and mannan-binding lectin-associated protein of 44 kDa (MAp44). Despite their obvious importance, the roles played by these proteins have never been investigated in leprosy disease. We haplotyped five MASP1 polymorphisms by multiplex sequence-specific PCR (intronic rs7609662*G>A and rs13064994*C>T, exon 12 3'-untranslated rs72549262*C>G, rs1109452*C>T and rs850314*G>A) and measured MASP-1, MASP-3 and MAp44 serum levels in 196 leprosy patients (60%, lepromatous) and 193 controls. Lower MASP-3 and MAp44 levels were observed in patients, compared with controls (P = 0.0002 and P<0.0001, respectively) and in lepromatous, compared with non-lepromatous patients (P = 0.008 and P = 0.002, respectively). Higher MASP-3 levels were present in controls carrying variants/haplotypes associated with leprosy resistance (rs13064994*T, rs1109452_rs850314*CG within GT_CCG and rs850314*A: OR = 0.5-0.6, Pcorr = 0.01-0.04). Controls with rs1109452*T, included in susceptibility haplotypes (GT_GTG/GT_CTG: OR = 2.0, Pcorr = 0.03), had higher MASP-1 and lower MASP-3 levels (P≤0.009). Those with GC_CCG, presented increasing susceptibility (OR = 1.7, Pcorr = 0.006) and higher MAp44 levels (P = 0.015). MASP-3 expression decreased in patients, compared with controls carrying rs1109452_rs850314*CA or CG (P≤0.02), which may rely on exon 12 CpG methylation and/or miR-2861/miR-3181 mRNA binding. Polymorphisms regulating MASP-3/MAp44 availability in serum modulate leprosy susceptibility, underlining the importance of lectin pathway regulation against pathogens that exploit phagocytosis to parasitize host macrophages.

Evidence for Mycobacterium leprae Drug Resistance in a Large Cohort of Leprous Neuropathy Patients from India.

Resistance to anti-leprosy drugs is on the rise. Several studies have documented resistance to rifampicin, dapsone, and ofloxacin in patients with leprosy. We looked for point mutations within the folP1, rpoB, and gyrA gene regions of the Mycobacterium leprae genome predominantly in the neural form of leprosy. DNA samples from 77 nerve tissue samples were polymerase chain reaction (PCR)-amplified for M leprae DNA and sequenced for drug resistance-determining regions of genes rpoB, folP1, and gyrA. The mean age at presentation and onset was 38.2 ± 13.4 (range 14-71) years and 34.9 ± 12.6 years (range 10-63) years, respectively. The majority had borderline tuberculoid leprosy (53 [68.8%]). Mutations associated with resistance were identified in 6/77 (7.8%) specimens. Mutations seen were those associated with resistance to rifampicin, ofloxacin, and dapsone. All the six patients were drug-naive. The clinical and pathological manifestations in this group did not differ from the drug-sensitive group. This study highlights the occurrence of resistance to the standard multidrug therapy and ofloxacin in leprosy. Among the entire cohort, 1/77 (1.3%) showed resistance to rifampicin, 2/77 (2.6%) to dapsone, and 5/77 (6.4%) to ofloxacin. Six new patients showing infection by mutant strains indicated the emergence of primary resistance. Resistance to ofloxacin could be due to frequent use of quinolones for many bacterial infections. The results of the study indicate the need for development of a robust and strict surveillance system for detecting drug resistance in leprosy in India.

Computational saturation mutagenesis to predict structural consequences of systematic mutations in the beta subunit of RNA polymerase in Mycobacterium leprae

Rifampin resistance in leprosy may remain undetected due to the lack of rapid and effective diagnostic tools. A quick and reliable method is essential to determine the impacts of emerging detrimental mutations in the drug targets. The functional consequences of missense mutations in the β-subunit of RNA polymerase (RNAP) in Mycobacterium leprae (M. leprae) contribute to phenotypic resistance to rifampin in leprosy. Here, we report in-silico saturation mutagenesis of all residues in the β-subunit of RNAP to all other 19 amino acid types (generating 21,394 mutations for 1126 residues) and predict their impacts on overall thermodynamic stability, on interactions at subunit interfaces, and on β-subunit-RNA and rifampin affinities (only for the rifampin binding site) using state-of-the-art structure, sequence and normal mode analysis-based methods. Mutations in the conserved residues that line the active-site cleft show largely destabilizing effects, resulting in increased relative solvent accessibility and a concomitant decrease in residue-depth (the extent to which a residue is buried in the protein structure space) of the mutant residues. The mutations at residue positions S437, G459, H451, P489, K884 and H1035 are identified as extremely detrimental as they induce highly destabilizing effects on the overall protein stability, and nucleic acid and rifampin affinities. Destabilizing effects were predicted for all the clinically/experimentally identified rifampin-resistant mutations in M. leprae indicating that this model can be used as a surveillance tool to monitor emerging detrimental mutations that destabilise RNAP-rifampin interactions and confer rifampin resistance in leprosy. Author summaryThe emergence of primary and secondary drug resistance to rifampin in leprosy is a growing concern and poses a threat to the leprosy control and elimination measures globally. In the absence of an effective in-vitro system to detect and monitor phenotypic resistance to rifampin in leprosy, diagnosis mainly relies on the presence of mutations in drug resistance determining regions of the rpoB gene that encodes the β-subunit of RNAP in M. leprae. Few labs in the world perform mouse footpad propagation of M. leprae in the presence of drugs (rifampin) to determine growth patterns and confirm resistance, however the duration of these methods lasts from 8 to 12 months making them impractical for diagnosis. Understanding molecular mechanisms of drug resistance is vital to associating mutations to clinically detected drug resistance in leprosy. Here we propose an in-silico saturation mutagenesis approach to comprehensively elucidate the structural implications of any mutations that exist or that can arise in the β-subunit of RNAP in M. leprae. Most of the predicted mutations may not occur in M. leprae due to fitness costs but the information thus generated by this approach help decipher the impacts of mutations across the structure and conversely enable identification of stable regions in the protein that are least impacted by mutations (mutation coolspots) which can be a potential choice for small molecule binding and structure guided drug discovery.

Leprosy: current status and clinical management

Abstract Around the world nations have adopted the global leprosy strategy 2016–2020 developed by the world health organization to achieve the objective of a leprosy-free world. Despite the disease having been declared as eliminated from most developed nations and parts of the world, every year more than 2,00,000 new cases of leprosy still continue to occur mainly in south east Asian regions (India, Indonesia, Philippines) and south American region of Brazil. The diagnosis of leprosy has remained more or less the same over the years with recent advances in the form of PCR-based molecular diagnosis and immunological markers. Much of the success of national programs have been due to multi-drug therapy. Recently, anti-microbial resistance surveys have shown the need to monitor for drug resistance in leprosy. The countries where the disease is still endemic need to shift their policy towards active surveillance and case finding in the affected districts. We are in the last year of the Global Leprosy Strategy 2016–2020 by WHO: accelerating towards a Leprosy free world, but eradication of the disease seems a distant possibility as of now.

Prospective study on antimicrobial resistance in leprosy cases diagnosed in France from 2001 to 2015

Antimicrobial resistance (AMR) in leprosy is mostly unknown because Mycobacterium leprae does not grow in vitro and bacteriologic investigations have been abandoned. However, molecular detection of resistance can be applied to multibacillary cases. Patients living in France mainland or in the French territories and diagnosed with leprosy from 2001 to 2015 were prospectively studied for AMR by detecting mutations in rpoB for rifampicin resistance, in folP1 for dapsone and in gyrA for ofloxacin. Single nucleotide polymorphism (SNP) genotypes 1–4 were determined for resistant strains. Of 334 skin biopsy samples received for suspicion of leprosy, 184 (55.1%) were positive for M. leprae (acid-fast bacilli and M. leprae–specific repetitive element PCR) corresponding to 160 multibacillary cases. AMR was detected in 18 cases (11.3%): 13 cases (8.1%) of dapsone resistance, three (1.9%) rifampicin and two (1.3%) ofloxacin. There were no strains with multidrug resistance. The mutations (numbering system of M. leprae TN strain genome) found were P55L (n = 7), T53I (n = 5), T53A (n = 1) in folP1; S456L (n = 2) and S456F (n = 1) in rpoB; and A91V (n = 2) in gyrA. Resistance proportion differ significantly between new and relapse cases (9/127, 7.0%, vs. 9/33, 25.7%, p 0.003). The frequency distribution of SNP1–4 types of resistant strains was two, one, 12 and three with five SNP3 cases from New Caledonia harbouring the same T53I FolP1 substitution. This is the first report of AMR surveillance for new and relapse cases of leprosy in Europe. Detection of resistance helped in individual treatment as well as in epidemiologic investigations.

Structural Implications of Mutations Conferring Rifampin Resistance in Mycobacterium leprae

The rpoB gene encodes the β subunit of RNA polymerase holoenzyme in Mycobacterium leprae (M. leprae). Missense mutations in the rpoB gene were identified as etiological factors for rifampin resistance in leprosy. In the present study, we identified mutations corresponding to rifampin resistance in relapsed leprosy cases from three hospitals in southern India which treat leprosy patients. DNA was extracted from skin biopsies of 35 relapse/multidrug therapy non-respondent leprosy cases, and PCR was performed to amplify the 276 bp rifampin resistance-determining region of the rpoB gene. PCR products were sequenced, and mutations were identified in four out of the 35 cases at codon positions D441Y, D441V, S437L and H476R. The structural and functional effects of these mutations were assessed in the context of three-dimensional comparative models of wild-type and mutant M. leprae RNA polymerase holoenzyme (RNAP), based on the recently solved crystal structures of RNAP of Mycobacterium tuberculosis, containing a synthetic nucleic acid scaffold and rifampin. The resistance mutations were observed to alter the hydrogen-bonding and hydrophobic interactions of rifampin and the 5′ ribonucleotide of the growing RNA transcript. This study demonstrates that rifampin-resistant strains of M. leprae among leprosy patients in southern India are likely to arise from mutations that affect the drug-binding site and stability of RNAP.

Antimicrobial resistance in leprosy: results of the first prospective open survey conducted by a WHO surveillance network for the period 2009–15

ObjectivesAntimicrobial resistance (AMR) is a priority for surveillance in bacterial infections. For leprosy, AMR has not been assessed because Mycobacterium leprae does not grow in vitro. We aim to obtain AMR data using molecular detection of resistance genes and to conduct a prospective open survey of resistance to antileprosy drugs in countries where leprosy is endemic through a WHO surveillance network. MethodsFrom 2009 to 2015, multi-bacillary leprosy cases at sentinel sites of 19 countries were studied for resistance to rifampicin, dapsone and ofloxacin by PCR sequencing of the drug-resistance-determining regions of the genes rpoB, folP1 and gyrA. ResultsAmong 1932 (1143 relapse and 789 new) cases studied, 154 (8.0%) M. leprae strains were found with mutations conferring resistance showing 182 resistance traits (74 for rifampicin, 87 for dapsone and 21 for ofloxacin). Twenty cases showed rifampicin and dapsone resistance, four showed ofloxacin and dapsone resistance, but no cases were resistant to rifampicin and ofloxacin. Rifampicin resistance was observed among relapse (58/1143, 5.1%) and new (16/789, 2.0%) cases in 12 countries. India, Brazil and Colombia reported more than five rifampicin-resistant cases. ConclusionsThis is the first study reporting global data on AMR in leprosy. Rifampicin resistance emerged, stressing the need for expansion of surveillance. This is also a call for vigilance on the global use of antimicrobial agents, because ofloxacin resistance probably developed in relation to the general intake of antibiotics for other infections as it is not part of the multidrug combination used to treat leprosy.