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.

Effectiveness and safety of levocetirizine 10 mg versus a combination of levocetirizine 5 mg and montelukast 10 mg in chronic urticaria resistant to levocetirizine 5 mg: A double-blind, randomized, controlled trial.

BACKGROUND: Chronic urticaria is a vexing problem for patients and treating physicians alike. The EAACI/GA[2]LEN/EDF/WAO guidelines advocate an increased antihistamine dosage up to four times the standard, before adding leukotriene receptor antagonists. Patients are frequently intolerant of these higher dosages. We conducted this study to determine whether the addition of leukotriene receptor antagonists to the standard antihistamine dose was comparable to higher dosages of antihistamines alone, in terms of efficacy, safety and quality of life changes. We compared levocetirizine 10 mg (double dose of standard) versus a combination of levocetirizine 5 mg and montelukast 10 mg in cases of chronic urticaria not responding to single daily dose of 5 mg levocetirizine. METHODS: A single-center, double-blind, randomized, active-controlled, parallel group phase IV trial (CTRI/2014/12/005261) was conducted on 120 patients of chronic urticaria of either sex not responding to 5 mg levocetirizine. Patients were randomized into receiving either levocetirizine 10 mg or levocetirizine 5 mg + montelukast 10 mg for 4 weeks. Primary outcome measures were Urticaria Activity Score (UAS) and Urticaria Total Severity Score (TSS). Routine hematological and biochemical tests and treatment-emergent adverse events were monitored for safety. RESULTS: Fifty-two patients on levocetirizine 10 mg group and 51 patients on levocetirizine 5 mg + montelukast 10 mg group were analyzed. UAS and TSS reduced significantly in both treatment groups and reduction of score were comparable in between the groups (P = 0.628, P = 0.824, respectively). Among adverse effects, sedation was noted significantly more (P = 0.013) in levocetirizine 10 mg group. Quality of life was significantly improved in levocetirizine 5 mg + montelukast 10 mg group (P = 0.031). LIMITATIONS: The limitation of the study was that the follow-up period was 4 weeks. CONCLUSION: EAACI/GA[2]LEN/EDF/WAO guidelines need to be more flexible in allowing usage of montelukast before escalation of anti-histamine dosage.

Late onset isotretinoin resistant acne conglobata in a patient with acromegaly.

A 55 year-old male presented with multiple pus-discharging abscesses and sinuses and mutilating scarring on the gluteal region and back prevalent for the last ten years with exacerbations and remissions. Physical examination revealed acromegaly with frontal bossing, prognathism, a barrel chest and acral hypertrophy. Dermatological examination revealed cutis verticis gyrata, thick eyelids, a large triangular nose, a thickened lower lip, macroglossia, widely spaced teeth and widened skin pores with wet and oily skin. Hair was fine and nails were flat and wide. There were multiple inflammatory papules, tender nodules, draining sinuses, and grouped, polyporous comedones as well as multiple and extensive depressed and keloidal scars localized predominantly over the gluteal region with a few scattered lesions over the back. A computed tomography (CT) scan showed widened sella turcica. His basal fasting growth hormone (GH) levels were markedly raised (230 ng/mL; normal 1-5 ng/mL) while the prolactin levels were moderately raised (87 ng/mL; normal 2-5 ng/mL). These findings were consistent with a diagnosis of acromegaly. The patient was put on antibiotics, nonsteroidal antiinflammatory drugs and isotretinoin at a dose of 1 mg/kg/day, which was increased to 1.5 mg/kg/day. Except for an initial mildly beneficial response, the skin lesions were largely resistant to high doses of isotretinoin at the end of four months.

Thalidomide resistance is based on the capacity of the glutathione-dependent antioxidant defense.

Thalidomide as an effective treatment for multiple myeloma and leprosy has also caused birth defects in thousands of children five decades ago particularly in Europe. Thus its use in humans remains limited. The rapid and fatal approval of thalidomide at that time ultimately was a consequence of the sole use of thalidomide-insensitive species in animal toxicity tests. Here, we aimed at elucidating the molecular basis for the resistance of mice to thalidomide teratogenicity. By using hydroethidine staining we demonstrate that thalidomide induces the formation of superoxide in embryonic fibroblasts of thalidomide-sensitive species but not in those of mice. As determined by trypan blue staining, scavenging of superoxide prevents thalidomide-induced apoptosis, a marker for thalidomide teratogenicity. Mouse embryonic fibroblasts are found to have higher glutathione levels than those of sensitive species and can be sensitized for thalidomide by glutathione depletion with diethyl maleate or diamide. Accordingly, experimental increase of glutathione levels in human embryonic fibroblasts by adding N-acetyl cysteine or glutathione ethyl ester to the culture medium counteracts thalidomide-induced apoptosis. Finally, we show that thalidomide-induced molecular pathology downstream of superoxide is essentially identical in human and sensitized mouse embryonic fibroblasts. In conclusion, thalidomide-resistance is based on the capacity of the glutathione-dependent antioxidant defense. We provide a basis to pharmacologically overcome the limitations of thalidomide use at humans and describe substantial differences between human and mouse embryonic cells regarding the protection against oxidative stress.