Mycobacterium leprae: aspectos da resistência aos fármacos na poliquimioterapia / Drug resistance in multidrug therapy for Mycobacterium leprae

Introdução: O diagnóstico da hanseníase possui números significativos que causam preocupação à saúde pública. Os casos de resistência medicamentosa nessa doença se iniciaram em meados dos anos 60 e diante do problema, a Organização Mundial da Saúde instituiu em 1981 a poliquimioterapia, associação dos antibióticos rifampicina, dapsona e clofazimina, tratamento atual de escolha. A resistência aos fármacos na hanseníase é reportada pela literatura, desvelando um obstáculo à sua eliminação. Apresentamos nessa revisão os principais aspectos da resistência medicamentosa no tratamento para hanseníase e seus impactos. Metodologia: Revisão sistemática sobre os aspectos da resistência medicamentosa utilizando a pesquisa exploratória como metodologia de abordagem. Foram pesquisados os termos resistência medicamentosa, hanseníase, recidiva, alterações genéticas e os operadores booleanos "and" e "or" na busca. Resultados e discussão: A dificuldade de tomar a medicação corretamente foi um dos principais fatores que acarretaram resistência do bacilo Mycobacterium leprae aos fármacos. Homens de países norte e sul-americanos e asiáticos foram os mais atingidos por episódios de resistência. A resistência medicamentosa é uma das principais causas de recidivas em hanseníase. O principal fármaco causador de resistência medicamentosa descrito nos trabalhos foi a dapsona (46,6%) e a maioria das alterações genéticas encontradas estão no gene rpoB; 23,2% dos registros relatados foram de resistência secundária aos fármacos e, também, sete casos de resistência múltipla a esses medicamentos. Conclusão: Os principais aspectos da resistência medicamentosa na hanseníase são os equívocos ao ingerir os medicamentos e as alterações genéticas na bactéria. Os impactos causados estão na dificuldade de refazer o tratamento, a possibilidade de nova transmissão e o aparecimento de sintomas mais graves.

Introduction: The diagnosis of leprosy has significant numbers causing public health concern. Reports of drug resistance in this disease begun in the mid-1960s and due to this problem, the World Health Organization instituted a multidrug therapy with rifampicin, dapsone, and clofazimine antibiotic association in 1981, which is currently the first-choice treatment for leprosy. Cases of drug resistance have been reported in literature, revealing an obstacle to the eradication of the disease. This paper has the purpose of presenting the key aspects and impacts of drug resistance in the treatment for leprosy. Methods: Systematic review of the drug resistance aspects using exploratory research as an approach methodology. The authors searched the terms drug resistance, leprosy, recurrence, genetic alterations, and the Boolean operators "and" and "or" between them. Results and discussion: The difficulty in taking the medication correctly was one of the key factors that led to drug resistance for Mycobacterium leprae. Men from North and South American, as well as from Asian countries, were the most affected by episodes of resistance. Drug resistance is one of the main causes of leprosy recurrences. Dapsone was the most frequently identified drug resistance in the studies (46.6%), while most of the genetic alterations were found in the rpoB gene; 23.2% of the cases were from secondary resistance episodes, and seven cases of multiple resistance were reported. Conclusion: The misconceptions when taking the treatment and the Mycobacterium leprae genetic alterations have been described as the key aspects of drugs resistance in leprosy and the impacts caused are the difficulty in redoing the treatment, the possibility of new transmission, and the appearance of more severe symptoms.

WQ-3810 inhibits DNA gyrase activity in ofloxacin-resistant Mycobacterium leprae.

BACKGROUND: Mycobacterium leprae causes leprosy and ofloxacin is used to control this bacterium. However, specific amino acid substitutions in DNA gyrases of M. leprae interferes with the effect of ofloxacin. METHODOLOGY/PRINCIPAL FINDINGS: Here we tested the inhibitory effect of WQ-3810 on DNA gyrases in M. leprae, using recombinant gyrases. We theorized that WQ-3810 and DNA gyrases interacted, which was tested in silico. Compared with control drugs like ofloxacin, WQ-3810 showed a better inhibitory effect on ofloxacin-resistant DNA gyrases. The in-silico study showed that, unlike control drugs, a specific linkage between a R1 group in WQ-3810 and aspartic acid at position 464 in the subunit B of DNA gyrases existed, which would enhance the inhibitory effect of WQ-3810. This linkage was confirmed in a further experiment, using recombinant DNA gyrases with amino acid substitutions in subunits B instead. CONCLUSIONS/SIGNIFICANCE: The inhibitory effect of WQ-3810 was likely enhanced by the specific linkage between a R1 group residue in its structure and DNA gyrases. Using interactions like the one found in the present work may help design new fluoroquinolones that contribute to halt the emergence of antibiotic-resistant pathogens.

An update on prevalence, diagnosis, treatment and emerging issues of genital mycoplasma infection in Indian women: A narrative review.

Despite adequate treatment of reproductive tract infection, there is persistence of symptoms in some patients. This raises the possibility of existence of other silent microbes with pathogenic potential. Apart from the common sexually transmitted organisms such as Chlamydia trachomatis and Neisseria gonorrhoeae, there are other silent and emerging pathogens, like genital mycoplasma, which have been associated with cervicitis, pelvic inflammatory disease, infertility, and pregnancy-related complications in women. Although these organisms were identified decades ago, they are still overlooked or ignored. There is a need to understand the role played by these organisms in Asian populations and their susceptibility to the standard line of treatment. Data on genital mycoplasma infections in Indian women is heterogeneous, with limited evidence of pathogenicity. Although known for their wide spectrum of reproductive morbidities in western counterparts, these microorganisms are yet to gain the attention of Indian clinicians and microbiologists. There is paucity of adequate information in India regarding these infections, so Indian literature was compiled to get an overview of these pathogens, their association with reproductive morbidities, and their response to treatment. Thus, there is a need to explore genital mycoplasma infections in Indian women, especially in the arena of antimicrobial resistance among genital mycoplasma, which has the potential to become a major problem. A literature search with keywords focusing on "genital mycoplasma", "sexually transmitted infections India", "sexually transmitted mycoplasma", and "characteristic of mycoplasma" was carried out through computerized databases like PubMed, MEDLINE, Embase, and Google Scholar.

Resistance to anti leprosy drugs in multi-bacillary leprosy: A cross sectional study from a tertiary care centre in eastern Uttar Pradesh, India.

BACKGROUND: : WHO MDT is the main drug regimen for treating leprosy and has been used for more than three decades. Many cases of relapse of leprosy have been reported, which points towards the emergence of drug resistance with the antileprotic drugs. OBJECTIVES: : To find the resistance with the antileprotic drugs by detecting the mutations in drug resistance determining region of the rpoB, folP1 and gyrA genes of Mycobacterium leprae. METHODS: Leprosy patients with bacterial index ≥2 were included in the study. The slides were further processed to extract genomic DNA, and polymerase chain reactions were performed to amplify the drug resistance determining region (DRDR) of rpoB, folP1 and gyrA genes. The samples in which genes could be amplified were subjected to DNA sequencing to detect mutations. RESULTS: Out of 78 samples rpoB gene was amplified in 39 (50%), folP1 in 32 (41%) and gyrA in 45 (57.7%). In 20 (25.6%) samples no gene was amplified. Only 32 samples of rpoB, 25 samples of folP1 and 38 samples of gyrA gene were included in the study, rest were excluded due to sequencing error. No mutation was seen in rpoB gene and in folP1 gene. In gyrA gene samples mutations were seen in 8 (21%) samples, and were present at codon 91 GCA → GTA (Alanine → Valine). LIMITATIONS: : Small sample size and less efficient method to detect resistance. CONCLUSION: Resistance is not a problem with conventional drugs in MDT. It is more common with quinolones.

A rapid screening assay for identifying mycobacteria targeted nanoparticle antibiotics.

Antibiotic resistance is a serious problem. Nanotechnology offers enormous potential in medicine, yet there is limited knowledge regarding the toxicity of nanoparticles (NP) for mycobacterial species that cause serious human diseases (e.g. tuberculosis (TB) and leprosy). Mycobacterial diseases are a major global health problem; TB caused by Mycobacterium tuberculosis (Mtb) kills up to 2 million people annually and there are over 200 000 leprosy cases each year caused by Mycobacterium leprae (M. leprae). Few drugs are effective against these mycobacteria and increasing antibiotic resistance exacerbates the problem. As such, alternative therapies are urgently needed but most current assays used to assess the effectiveness of therapeutics against mycobacteria are slow and expensive. This study aimed to develop a rapid, low-cost assay which can be used for screening the antimicrobial properties of compounds against pathogenic mycobacteria and to assess the toxicity of three NP (silver [Ag], copper oxide [Cu(II)O], and zinc oxide [ZnO]) against a green fluorescent protein reporter strain of Mycobacterium avium subspecies paratuberculosis, a slow growing, pathogenic mycobacterial species causing paratuberculosis in ruminants. Fluorescence was used to monitor mycobacterial growth over time, with NP concentrations of 6.25-100 µg/mL tested for up to 7 days, and a method of data analysis was designed to permit comparison between results. Mycobacterial sensitivity to the NP was found to be NP composition specific and toxicity could be ranked in the following order: Ag > Cu(II)O > ZnO.

[Rapid detection of mutations related to Mycobacterium leprae drug resistance by using Hp-rPCR (hairpin primer- real time PCR) method].

Rapid and simple detection method of drug resistance bacteria is required. In the present study, Hp-rPCR (hairpin primer-real time PCR) was applied to Mycobacterium leprae genes to detect mutations. Target sites of the method were as follows: first base and second base on 53rd codon and second base on 55th codon infolP1 gene for dapsone resistance, first base on 441st codon and 451st codon and second base on 456th and 458th codon in rpoB gene for rifampicin resistance, and first base on 89th codon and second base on 91st codon in gyrA gene for quinolone resistance which were common mutation sites in clinical reports. The total number of the target sites was 9. Mycobacterium leprae, Thai-53, Zensho-2 and Zensho-4 were used as reference bacteria in the present study and clear, reliable results were obtained. Double-blind study was conducted using 15 samples. The number of target sites was calculated as 135 in total by 9 sites in 15 samples. There was only one misreading in the blind samples and the sensitivity was more than 99%.

Is it easy to stop RNA polymerase?

Among transcription factors that bind to bacterial RNA polymerase (RNAP) and modulate its activity, a number of small molecules irreversibly inhibit RNAP thereby causing cell death. To be of clinical significance such inhibitors must (1) inhibit a broad range of bacterial RNAPs but not affect human cells, (2) penetrate bacterial cell walls and (3) circumvent bacterial resistance mechanisms. Rifamycins, the only class of RNAP inhibitors that have found their way into clinical practice, are widely used in the treatment of tuberculosis and leprosy. However, the practical value of this class of antibiotics is limited by a rapid rise in resistant bacterial isolates. In this review we focus on recent advances in studies of prokaryotic transcription that allow a detailed structural and functional characterization of a number of RNAP/rifamycins complexes, thereby opening new opportunities for the design of superior antibacterial agents.