Efficacy of moxifloxacin & econazole against multidrug resistant (MDR) Mycobacterium tuberculosis in murine model.

BACKGROUND & OBJECTIVES: Studies have shown the bactericidal potential of econazole and clotrimazole against Mycobacterium tuberculosis under in vitro and ex vivo conditions along with their synergism with conventional antituberculosis drugs. These molecules were also found to be effective against different multidrug resistant (MDR) M. tuberculosis isolates in vitro. Hence the present study was designed to evaluate the in vivo antimycobacterial potential of moxifloxacin and econazole alone and in combination against multidrug resistant tuberculosis (MDR-TB) in a mice model. METHODS: Mice were infected with 2.5×10 [7] bacilli of MDR strain of M. tuberculosis by aerosol route of infection. After four weeks of infection, chemotherapy was started orally by moxifloxacin 8.0 mg/kg body wt and econazole 3.3 mg/kg alone and in combination, as well as with four first line anti-tuberculosis drugs as a positive control. The animals were sacrificed and the lungs and spleen were excised under aspetic conditions. The tissues were homogenized with sterile normal saline, an aliquot of the homogenate was plated on Middlebrook 7H11 agar supplemented with oleate albumin dextrose catalase (OADC) and incubated at 37°C for four weeks. The number of visible and individual colonies were counted. RESULTS: The first line anti-tuberculosis drugs (RIF+INH+EMB+PZA) after eight weeks of therapy had no impact as the bacillary load in lungs and spleens remained unchanged. However, econazole, moxifloxacin alone as well as in combination significantly reduced the bacillary load in lungs as well as in spleens of MDR-TB bacilli infected mice. INTERPRETATION & CONCLUSIONS: Co-administration of the two drugs (econazole and moxifloxacin) to MDR-TB strain JAL-7782 infected mice exhibited additive effect, the efficacy of the drugs in combination being higher as compared with ECZ or MOX alone. These results were substantiated by histopathological studies. This study suggests the utility of econazole for the treatment of MDR tuberculosis and warrants further work in this direction.

Characterization of an acid inducible lipase Rv3203 from Mycobacterium tuberculosis H37Rv.

The Rv3203 (LipV) of Mycobacterium tuberculosis (Mtb) H37Rv, is annotated as a member of Lip family based on the presence of characteristic consensus esterase motif 'GXSXG'. In vitro culture studies of Mtb H37Ra indicated that expression of Rv3203 gene was up-regulated during acidic stress as compared to normal whereas no expression was observed under nutrient and oxidative stress conditions. Therefore, detailed characterization of Rv3203 was done by gene cloning and its further expression and purification as his-tagged protein in microbial expression system. The enzyme was purified to homogeneity by affinity chromatography. It demonstrated broad substrate specificity and preferentially hydrolyzed p-nitrophenyl myristate. The purified enzyme demonstrated an optimum activity at pH 8.0 and temperature 50 °C. The specific activity, K m and V max of enzyme was determined to be 21.29 U mg(-1) protein, 714.28 µM and 62.5 µmol ml(-1) min(-1), respectively. The pH stability assay and circular dichroism spectroscopic analysis revealed that Rv3203 protein is more stable in acidic condition. Tetrahydrolipstatin, a specific lipase inhibitor and RHC80267, a diacylglycerol lipase inhibitor abolished the activity of this enzyme. The catalytic triad residues were determined to be Ser50, Asp180 and His203 residues by site-directed mutagenesis.

Molecular mimicry between HSP 65 of Mycobacterium leprae and cytokeratin 10 of the host keratin; role in pathogenesis of leprosy.

Mycobacteria are known to induce autoimmune response in the host. Anti-host keratrin antibodies (AkAbs) might be responsible for the autoimmune phenomena in leprosy patients as majority of leprosy lesions are manifested in the skin and occurrence of keratosis is not an uncommon feature. The aim of this study was to find out the level of AkAbs in leprosy patients across the spectrum and to explore its correlation with the clinical manifestation of the disease. Further, mimicking epitopes of keratin and Mycobacterium leprae components were characterized. We screened 140 leprosy patients (27 BT, 28 BL, 41 LL, 25 T1R, 19 ENL), 74 healthy controls (HC) and 3 psoriasis patients as positive control. Highest AkAbs level was observed in the psoriasis patients followed by T1R, LL, BL, ENL, TT/BT. AkAbs level was significantly (p<0.05) higher in all the groups of leprosy patients except TT/BT in comparison to HC. Significant positive correlation was found between number of lesions and level of AkAbs in leprosy patients. Highest lympho-proliferation for keratin protein was observed in T1R, followed by BL/LL, TT/BT, ENL. Lympho-proliferation was significantly (p<0.05) higher in all groups of leprosy patients except ENL in comparison to HC. Interestingly, it was noted that hyperimmunization of inbred strains of female BALB/c mice and rabbit with M. leprae soluble antigen (MLSA) induce higher level of AkAbs. The percentage of FoxP3(+) expressing Treg cells (total CD4(+)CD25(+)FoxP3(+) andCD4(+)CD25(+hi)FoxP3(+)) in splenocytes and lymph nodes of hyperimmunized mice were declined in comparison to control mice. Further, it was found that this autoimmune response can be adoptively transferred in naïve mice by splenocytes and lymph node cells as well as T cells. Comparative molecular characterization between keratin and MLSA noted a cross-reactivity/similarity between these two antigens. The cross-reactive protein of keratin was found to be in molecular weight range ≈74-51kDa and at pI 4.5 while the cross-reactive protein of MLSA was found to be in molecular weight ≈65kDa and at pI 4-4.5. Cross-reactive protein of keratin and MLSA was identified and characterized by MALDI-TOF/TOF analysis and Mascot software. It was found that the keratin (host protein) which reacted with anti-M. leprae sera is cytokeratin-10 and MLSA which reacted with anti-keratin sera is heat shock protein 65 (HSP 65). Seven B-cell epitopes of cytokeratin-10 and HSP 65 was found to be similar by multiple sequence alignment using ClustalW server and out of which 6 B-cell epitopes were found to be on the surface of HSP 65. In conclusion, our study provides evidence for the existence of molecular mimicry between cytokeratin-10 of keratin (host protein) and 65kDa HSP (groEL2) of M. leprae. Presence of heightened CMI response of leprosy patients to keratin and positive correlation of AkAbs level with number of lesions of leprosy patients showed the clinical evidence for its role in the pathogenesis in leprosy.

Mycobacterium indicus pranii as stand-alone or adjunct immunotherapeutic in treatment of experimental animal tuberculosis.

BACKGROUND & OBJECTIVES: Mycobacterium w (M.w) is a saprophytic cultivable mycobacterium and shares several antigens with M. tuberculosis. It has shown good immunomodulation in leprosy patients. Hence in the present study, the efficacy of M.w immunotherapy, alone or in combination with multi drug chemotherapeutic regimens was investigated against drug sensitive M. tuberculosis H37Rv and three clinical isolates with variable degree of drug resistance in mice. METHODS: BALB/c mice were infected with M. tuberculosis H37Rv (susceptible to all first and second line drugs) and three clinical isolates taken from the epository of the Institute. The dose of 200 bacilli was used for infection via respiratory route in an aerosol chamber. Chemotherapy (5 days/wk) was given one month after infection and the vaccinated group was given a dose of 1x107 bacilli by subcutaneous route. Bacterial load was measured at 4 and 6 wk after initiation of chemotherapy. RESULTS: M.w when given along with chemotherapy (4 and 6 wk) led to a greater reduction in the bacterial load in lungs and other organs of TB infected animals compared to. However, the reduction was significantly (P<0.05) more in terms of colony forming units (cfu) in both organs (lungs and spleen). CONCLUSION: M.w (as immunomodulator) has beneficial therapeutic effect as an adjunct to chemotherapy.

Development and characterization of rifampicin loaded floating microspheres.

Gastroretentive floating microspheres have a potential for enhancing the bioavailability and controlled delivery of drugs. The present study involves development of rifampicin floating microspheres in order to increase the gastric retention time. The microspheres were prepared by solvent evaporation technique and characterized for particle size, shape, zeta-potential, entrapment, and release kinetics. The developed systems were almost spherical in shape. The entrapment efficiency was found to be 86.34%. The percentage buoyancy after 8 hours was found to be 61.06. The prepared microspheres exhibited prolonged drug release in gastric medium and hence could be utilized for sustained delivery of anti-tubercular drugs.

Immunogenicity and protective efficacy of "Mycobacterium w" against Mycobacterium tuberculosis in mice immunized with live versus heat-killed M. w by the aerosol or parenteral route.

As the disease caused by Mycobacterium tuberculosis continues to be a burden, there is a concerted effort to find new vaccines to combat this problem. One of the important vaccine strategies is whole bacterial vaccines. This approach relies on multiple antigens and built-in adjuvanticity. Other mycobacterial strains which share cross-reactive antigens with M. tuberculosis have been considered as alternatives to M. bovis for vaccine use. One such strain, "Mycobacterium w", had been evaluated for its immunomodulatory properties in leprosy. A vaccine against leprosy based on killed M. w is approved for human use, where it has resulted in clinical improvement, accelerated bacterial clearance, and increased immune responses to Mycobacterium leprae antigens. M. w shares antigens not only with M. leprae but also with M. tuberculosis, and initial studies have shown that vaccination with killed M. w induces protection against tuberculosis in Mycobacterium bovis BCG responder, as well as BCG nonresponder, strains of mice. Hence, we further studied the protective potential of M. w and the underlying immune responses in the mouse model of tuberculosis. We analyzed the protective efficacy of M. w immunization in both live and killed forms through the parenteral route and by aerosol immunization, compared with that of BCG. Our findings provide evidence that M. w has potential protective efficacy against M. tuberculosis. M. w activates macrophage activity, as well as lymphocytes. M. w immunization by both the parenteral route and aerosol administration gives higher protection than BCG given by the parenteral route in the mouse model of tuberculosis.

Animal models of tuberculosis for vaccine development.

Animal models for testing different vaccine candidates have been developed since a long time for studying tuberculosis. Mice, guinea pigs and rabbits are animals most frequently used. Each model has its own merits for studying human tuberculosis, and none completely mimics the human disease. Different animal models are being used depending upon the availability of the space, trained manpower as well as other resources. Efforts should continue to develop a vaccine which can replace/outperform the presently available vaccine BCG.

Comparative growth pattern of multi drug resistance versus susceptible isolates of Mycobacterium tuberculosis in mice lungs.

BACKGROUND & OBJECTIVE: Rise in prevalence of multi-drug resistance (MDR) in tubercle bacilli is a serious cause of concern. As mutations with two house keeping genes rpoB and katG are associated with resistance to two important anti-tubercular drugs rifampicin and isoniazid respectively, there is a need to understand the growth kinetics of organisms with such mutated genes in experimental animals. This study was undertaken to study the growth kinetics of susceptible as well multi-drug resistance Mycobacterium tuberculosis isolates in mice. METHODS: Two MDR (having mutations in rpoB and catG) and two drug susceptible isolates of M. tuberculosis along with H37Rv were grown in mice after aerogenic infection. RESULTS: The MDR isolates grew slowly up to 3 wk though the growth was significantly different from sensitive strains. However, after 3 wk, the growth in sensitive as well MDR strains was similar, suggesting that even the mutations in the MDR strains did not have any impact on the growth kinetics. INTERPRETATION & CONCLUSION: The effect of mutations in other parts of these genes need to be studied. Retention of property of MDR strains to establish infection after aerogenic infection has epidemiological significance in terms of the transmission of MDR tuberculosis.

Study of rifampicin resistance and comparison of dapsone resistance of M. leprae in pre- and post-MDT era.

The aim of this study to study the drug resistance patterns of dapsone (pre- and post-MDT) and rifampicin (post-MDT era). All the 84 patients from pre-MDT period (1985-1990) and 77 patients for post-MDT period (1990-2002) reporting to a tertiary care hospital-NJIL & OMD, Agra and referred for drug susceptibility testing were included in the study. Drug resistance was studied by mouse foot pad method. Dapsone resistance was high during pre-MDT era i.e. 8.3% (medium) and 19.1% (high) with an overall dapsone resistance of 27.4%. During the post-MDT era, the dapsone resistance was low i.e. 1.3% (medium) and 3.9% (high) respectively (overall dapsone resistance-5.2%). While no comparison with pre-MDT era is available, the rifampicin resistance in these selected self-reporting cases during the post-MDT era was comparatively rather high (9.1%). MDT appears to have been useful in reducing the prevalence of dapsone resistance in leprosy patients reporting to a tertiary care hospital.

Long term follow-up results of 1 year MDT in MB leprosy patients treated with standard MDT + once a month Minocycline and Ofloxacin.

BACKGROUND: This study was initiated in consultation with the National Leprosy Eradication Programme (NLEP) in mid nineties to try new treatment regimens for leprosy which were more robust in terms of control of reactions, long term relapses, operationally easier to undertake and feasible in field conditions. It was also envisaged to see if the addition of newer bactericidal drugs would be beneficial. OBJECTIVES: (i) To test the feasibility, safety and response of the patients to the new regimen. (ii) To observe the incidence of reactions during and after stoppage of therapy, for a period of 8-10 years after release from treatment. MATERIALS AND METHODS: A total of one hundred skin smear positive MB patients (15 LL, 35 BL and 50 BB) patients were included in this study. All the patients received the standard MDT + once a month supervised 100 mg of Minocycline and 400 mg of Ofloxacin for 12 months during the treatment phase. Thereafter, the treatment was stopped in all the patients which were followed-up on placebo (B complex tablets). Of these, 70 patients completed the treatment schedule of one year therapy and the post treatment follow-up of 9 to 10 years. RESULTS: All the patients tolerated the drugs well. The clinical response of the patients to the treatment was very good of which 32.85% of cases had history of reactions before starting treatment. During treatment, the incidence of reactions increased marginally to 38.5%, but these were easily controlled with concurrent administration of steroids. After completion of treatment the incidence was much less i.e. 10% and 3% after 1 and 2 years of post treatment follow-up respectively. The overall relapse rate is 5.7% (4/70) with an incidence density of 0.05/100 patient years. Relapses were confirmed by clinical, bacteriological, molecular biological (rRNA probes and 36 kD targeting PCR) as well as ATP bioluminescence. The relapsed patients presented with the appearance of new lesions, slit-skin smears were again found to become positive after becoming negative. Three of the four cases who relapsed had the initial mean BI of 2 to 2.9+ whereas one had the initial mean BI of 1.5+. Also, 2 of the 4 relapsed patients had positive PCR signals at the time of stoppage of treatment. CONCLUSION: The addition of Minocycline and Ofloxacin to the standard FDT has been observed to be a well tolerated. Overall as of now, the incidence of reactions observed with the newer treatment regimen is found to be significantly lower than that of 2 years fixed duration MB-MDT. The efficacy of this regimen regarding bacteriological clearance and relapse rates could not be compared due to non-availability of the results of experience with standard 1 year MDT regimen. However, this regimen appears to be operationally feasible and safe for the users.

Development and evaluation of real-time RT-PCR assay for quantitative estimation of viable Mycobacterium leprae in clinical samples.

Detection of live organisms by molecular methods has special significance in leprosy where causative organism can not be cultivated in vitro. Such techniques would be especially important for monitoring the progress of the disease. While real-time RT- PCR technology will be appropriate for this purpose, there is very little experience of use of such tools in leprosy. This study describes the development of a quantitative RT-PCR targeting 16S rRNA based on primers used in a semi quantitative RT-PCR and its application on clinical samples including slit scraping and biopsies. RNA was extracted from biopsies from 3 lepromatous leprosy (LL) cases and standard curve was generated by plotting crossing over point against the dilutions of input RNA quantity (number of bacilli used for RNA extraction). Real-time RT-PCR was performed for quantitative detection of live M. leprae in 28 slit (13/28 smear positive) scrappings and 32 biopsies (22/32 smear positive). Number of viable bacteria as estimated by solid stained bacilli and real-time PCR correlated (no difference p>0.05). The test achieved a theoretical analytical sensitivity limit of up to single live bacillus even considering 11.3% efficiency of RNA preparation which was calculated by spiking of known number of leprosy bacilli in non leprosy skin biopsies (PCR negative). All smear positive cases were positive by this assay. This assay appears to be a promising tool for detection and quantification of viable bacilli in selected clinical situations and should be of use even in smear negative cases also.

Expression profile of CXCL12 chemokine during M. tuberculosis infection with different therapeutic interventions in guinea pig.

Mycobacterium indicus pranii (MIP) already established as an immune-modulator in mycobacterial infections generates immune response by acting on CXC chemokines. In the present study, the immunomodulatory effect of MIP in conjunction with chemotherapy against M.tb infection was evaluated by colony forming units (CFUs) following aerosol infection to guinea pig and by measuring CXCL12 chemokine expression using q-PCR and in situ RT-PCR. Different experimental groups included, infection (Rv), immunoprophylaxis (RvMw), chemotherapy (RvCh) and combination of immunoprophylaxis+chemotherapy (RvChMw) group and normal healthy (NH) group. In the combination of immunoprophylaxis+chemotherapy (RvChMw) group, the CFU counts reduced significantly (p<0.001) at 4th week of infection as compared to other treated groups (RvMw and RvCh group). The expression of CXCL12 was recorded in all the treated groups of animals. The study demonstrated suppressed expression of CXCL 12 in both immunoprophylaxis as well as chemotherapy groups (6th and 8th week) that become elevated in immunoprophylaxis plus chemotherapy group (10th week), at which time point no CFUs were detected in RvCh and RvChMw group. The findings indicate that the expression of CXCL12 is associated with good response to anti - tubercular treatment. Thus, prior immunization with MIP appears to show good immunomodulatory effect to release CXCL12 chemokine during infection and also correlates with enhanced effect to chemotherapy.

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

OBJECTIVES: Antimicrobial 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. METHODS: From 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. RESULTS: Among 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. CONCLUSIONS: This 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.

Simultaneous ethambutol & isoniazid resistance in clinical isolates of Mycobacterium tuberculosis.

BACKGROUND & OBJECTIVE: There is a need to understand the nature of drug resistance patterns and predictors of emergence of drug resistance in Mycobacterium tuberculosis. There could be common factors/mechanisms for resistance to the drugs, isoniazid and ethambutol, both acting on cell wall. The present study was conducted to analyze the antimycobacterial susceptibility patterns of M. tuberculosis isolates to determine the minimum inhibitory concentrations (MICs) of ethambutol for M. tuberculosis; and to find out possible association of ethambutol resistance with isoniazid resistance. METHODS: A total of 380 M. tuberculosis isolates were tested for their susceptibilities to ethambutol at 2, 4, 6 microg/ml, isoniazid at 1 microg/ml and rifampicin at 64 microg/ml using MIC method. RESULTS: 44.21, 24.73 and 14.21 per cent isolates were resistant to ethambutol at concentrations of 2, 4 and 6 microg/ml respectively. At 6 microg/ml of ethambutol concentration, 85.18 per cent ethambutol resistant isolates were resistant to isoniazid also. At the same ethambutol concentration a fraction of 28.75 per cent isoniazid resistant isolates were ethambutol resistant. INTERPRETATION & CONCLUSION: Ethambutol resistance was accompanied with isoniazid resistance in a large percentage of isolates whereas ethambutol resistance was weakly linked with multidrug resistance. On the other hand, association between isoniazid and ethambutol resistance was weak showing one way linkage.

Animal models of tuberculosis.

It was Robert Koch who recognized the spectrum of pathology of tuberculosis (TB) in different animal species. The examination of clinical specimens from infected humans and animals confirmed the variable patterns of pathological reactions in different species. Guinea pigs are innately susceptible while humans, mice and rabbits show different level of resistance depending upon their genotype. The studies of TB in laboratory animals such as mice, rabbits and guinea pigs have significantly increased our understanding of the aetiology, virulence and pathogenesis of the disease. The introduction of less than five virulent organisms into guinea pigs by the respiratory route can produce lung lesions, bacteraemia and fatal diseases, which helped the extrapolation of results of such experiments to humans. The similarities in the course of clinical infection between guinea pigs and humans allow us to model different forms of TB and to evaluate the protective efficacy of candidate vaccines in such systems. The only limitation of this model, however, is a dearth of immunological reagents that are required for the qualitative and quantitative evaluation of the immune responses, with special reference to cytokines and cell phenotypes. Another limitation is the higher cost of guinea pigs compared with mice. The rabbit is relatively resistant to Mycobacterium tuberculosis, however following infection with virulent Mycobacterium bovis, the rabbit produces pulmonary cavities like humans. The rabbit model, however, is also limited by the lack of the immunological reagents. Mice are the animal of choice for studying the immunology of mycobacterial infections and have contributed much to our current understanding of the roles of various immunological mechanisms of resistance. The resistance of mice to the development of classic TB disease, however, represents a significant disadvantage of the mouse model. Although non-human primates are closely related to humans, owing to high cost and handing difficulties they have not been exploited to a large extent. As all existing animal models fail to mimic the human disease perfectly, efforts should be focused on the development of the non-human primate(s) as the alternative animal model for TB.

Molecular mimicry between Mycobacterium leprae proteins (50S ribosomal protein L2 and Lysyl-tRNA synthetase) and myelin basic protein: a possible mechanism of nerve damage in leprosy.

Autoantibodies against various components of host are known to occur in leprosy. Nerve damage is the primary cause of disability associated with leprosy. The aim of this study was to detect the level of autoantibodies and lympho-proliferative response against myelin basic protein (MBP) in leprosy patients (LPs) and their correlation with clinical phenotypes of LPs. Further, probable role of molecular mimicry in nerve damage of LPs was investigated. We observed significantly high level of anti-MBP antibodies in LPs across the spectrum and a positive significant correlation between the level of anti-MBP antibodies and the number of nerves involved in LPs. We report here that 4 B cell epitopes of myelin A1 and Mycobacterium leprae proteins, 50S ribosomal L2 and lysyl tRNA synthetase are cross-reactive. Further, M. leprae sonicated antigen hyperimmunization was responsible for induction of autoantibody response in mice which could be adoptively transferred to naive mice. For the first time our findings suggest the role of molecular mimicry in nerve damage in leprosy.

Understanding the phenomenon of persistence in mycobacterial infections.

Persistence of live organisms despite chemotherapy for long periods is a significant problem in both leprosy and tuberculosis. The consequence of this persistence is varying rates of relapses which undermine the success of treatment. The mechanisms of the dormancy are ill-understood, and as explanation a switch over to alternate modes of metabolism such as glyoxylate bypass and other shunts has been suggested. This presentation reviews the information available on this aspect. In-depth studies by designing and investigating model system(s) using molecular genetic approaches may help in gaining better understanding of the mechanisms of dormancy and persistence in mycobacterial infections and devising appropriate strategies and tools for the better management of these complications.

Drug resistance in leprosy: lessons from past and future perspective.

Some recent studies indicate that the problem of drug resistance in leprosy is very much there but the exact picture is not clear. In the emerging scenario with increasing number of new cases with low bacterial load, the conventional in-vivo and most of current in-vitro methods for determination of drug resistance may not help. It is pointed out that newer molecular approaches may be more useful and that it will be important to undertake studies to develop such tools.

Assessment of viability by normal mouse foot-pad and bacillary ATP bioluminescence assay in multibacillary cases treated with an MDT regimen using conventional as well as newer drugs like minocycline and ofloxacin.

The therapeutic effect of a drug regimen of conventional drugs as well as newer drugs like ofloxacin and minocycline in smear-positive multibacillary (MB) leprosy cases was assessed by mouse foot-pad and ATP bioluminiscence methods. Biopsies were taken before starting treatment and after one year of treatment. They were processed for viability assessment by normal mouse foot-pad inoculation and bacillary ATP assay techniques. The test regimen was quite effective in its anti-bacterial effect as it was found to result in loss of bacillary viability in all the cases, as assessed by both methods.

Chemotherapy trials in MB leprosy using conventional and newer drugs pefloxacin and minocycline.

One hundred, untreated, smear positive BB, BL and LL patients were treated with a regimen comprising of once a month, supervised, 600 mg of Rifampicin+ 400 mg Ofloxacin + 100 mg of Minocycline in addition to self administered 100 mg dapsone and 50 mg of clofazimine daily for twelve months.The treatment was then stopped and patients were followed up on placebo. This study reports the preliminary results after 2.5 to 3.5 years of post treatment follow-up. The drugs were well tolerated, the clinical response to the treatment was very good, and there was no case of treatment failure. Bacteriologically 25 out of the total 70 patients available for follow- up were still positive at the end of one year of treatment. These patients continued to progress satisfactorily and four patients were still positive at the end of 2 years. No growth was observed in the normal mouse foot pad after one year of therapy. No bacillary ATP was detected in the biopsy tissues after one year. While no M. leprae specific rRNA was detectable in any of the specimens after one year of treatment, weak PCR signals were detectable in 3/57 specimens at that period. In the follow up available no patient has relapsed. The patients are being followed up on placebo and longer follow-up is required to draw firm conclusions.