RESUMO
Introduction: Visceral leishmaniasis (VL) is a life-threatening infection remaining as one of the most neglected tropical diseases around the world. Despite scientific advances, an accurate diagnosis of VL remains a challenge. Loop-mediated isothermal amplification (LAMP) has emerged as a promising diagnostic tool with the possibility of becoming a point-of-care test to guide VL diagnosis and treatment.Areas covered: We conducted a systematic review assessing LAMP systems for diagnosing VL from 2000 to 2019. We performed structured searches in PubMed, LILACS, Scopus, and Web of Science without language restriction. Two reviewers screened articles, completed the data extraction and assessment of the risk of bias. A qualitative summary of the included studies was performed.Expert opinion: LAMP could be used as a screening test for VL diagnosis, so tissue aspiration could be performed only for those who are LAMP negative. We recommend more studies about the performance of the Loopamp™ Leishmania Detection kit and the Brazilian LAMP assay. Thus, we expect in the future the constitution of an international consortium to share experiences, projects, and other LAMP approaches mainly among researchers and institutions located within VL endemic countries.
Assuntos
Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/parasitologia , Técnicas de Amplificação de Ácido Nucleico , Brasil , Humanos , Leishmania , Leishmania donovani/genética , Testes Imediatos , Kit de Reagentes para Diagnóstico , Sensibilidade e EspecificidadeRESUMO
Yersinia pestis, the etiologic agent of plague, harbors three well-characterized plasmids: pFra (90-110kb), pYV (70 kb) and pPst (9.5 kb). Furthermore, some extra-cryptic DNA bands have been observed in a number of wild strains from several foci of the world. Additional bands have also been reported in Brazilian strains. Looking for any relationship among these cryptic DNA bands and the three-prototypical plasmids, we analyzed twelve strains displaying different plasmid content. The DNA bands were hybridized by southern blot with probes directed at the genes caf1, lcrV and pla located respectively on the plasmids pFra, pYV and pPst. The probes were constructed by PCR amplification and labeled with digoxigenin. The Pla probe hybridized with its target (pPst) and with bands of about 35 kb suggesting some homology among them. The Caf1 probe hybridized with the target (pFra) as well as with higher bands. The LcrV also hybridized with the target (pYV) and both with the bands higher than pFra and the bands between pFra and pYV. These results suggest that the large-cryptic bands could represent some rearrangement, open circular or linearized forms of the pFra and pYV plasmids.
Yersinia pestis, o agente causador da peste, possui três plasmídios bem caracterizados: pFra (90-110 kb), pYV (70 kb) e pPst (9.5 kb). Adicionalmente, algumas bandas extras de DNA críptico têm sido observadas em numerosas cepas selvagens em vários focos do mundo. Bandas extras também foram observadas em cepas brasileiras. Para verificar se existe alguma homologia entre as bandas extras de DNA críptico e os três plasmídios típicos, foram analisadas 12 culturas de Y. pestis através de hibridização com sondas dirigidas aos genes caf1, lcrV e pla localizados respectivamente nos plasmídios pFra, pYV e pPst. As sondas foram construídas através de amplificação por PCR e marcadas com digoxigenina. A sonda Pla reconheceu seu alvo (pPst) e bandas de cerca de 35 kb sugerindo que estas últimas podem se tratar de um multímero do pPst. A sonda Caf1 reconheceu seu alvo (pFra) assim como bandas mais altas. A sonda LcrV, além de reconhecer seu alvo (pYV), também hibridizou com bandas maiores que pFra e bandas de tamanho entre as de pFra e pYV. Estes resultados sugerem que as bandas grandes poderiam ser resultantes de algum rearranjo, formas abertas circulares ou linearizadas dos plasmídios pFra e pYV.