Antimony resistance in Leishmania (Viannia) braziliensis clinical isolates from atypical lesions associates with increased ARM56/ARM58 transcripts and reduced drug uptake

BACKGROUND In addition to the limited therapeutic arsenal and the side effects of antileishmanial agents, drug resistance hinders disease control. In Brazil, Leishmania braziliensis causes atypical (AT) tegumentary leishmaniasis lesions, frequently refractory to treatment. OBJECTIVES The main goal of this study was to characterise antimony (Sb)-resistant (SbR) L. braziliensis strains obtained from patients living in Xakriabá indigenous community, Minas Gerais, Brazil. METHODS The aquaglyceroporin 1-encoding gene (AQP1) from L. braziliensis clinical isolates was sequenced, and its function was evaluated by hypo-osmotic shock. mRNA levels of genes associated with Sb resistance were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Atomic absorption was used to measure Sb uptake. FINDINGS Although clinical isolates presented delayed recovery time in hypo-osmotic shock, AQP1 function was maintained. Isolate 340 accumulated less Sb than all other isolates, supporting the 65-fold downregulation of AQP1 mRNA levels. Both 330 and 340 isolates upregulated antimony resistance marker (ARM) 56/ARM58 and multidrug resistant protein A (MRPA); however, only ARM58 upregulation was an exclusive feature of SbR field isolates. CA7AE seemed to increase drug uptake in L. braziliensis and represented a tool to study the role of glycoconjugates in Sb transport. MAIN CONCLUSIONS There is a clear correlation between ARM56/58 upregulation and Sb resistance in AT-harbouring patients, suggesting the use of these markers as potential indicators to help the treatment choice and outcome, preventing therapeutic failure.

Differentiation Between Vaccine Strain and Field Isolates of Classical Swine Fever Virus Using Polymerase Chain Reaction and Restriction Test / 微生物学通报

A nest RT-PCR/restriction test has been developed in order to distinguish the lapinised vaccine strain from field isolates of classical swine fever virus. The restriction enzyme cut sites mapping of the major coding sequence of E2 gene lapinised vaccine strain and ShiMen strain of classical swine fever virus have been compared. Ten and sixteen unique restriction markers have been found in the lapinised vaccine strain and ShiMen strain. The restriction enzyme cut sites mapping of the twenty six unique restriction marker in the major coding sequence of E2 gene of 17 classical swine fever field isolates have been analyzed. Only 3 sites (HgaI、Hin8I及Hsp92I) are present in the lapinised vaccine strain sequence. Two pans of nested primers and a criteria of analysis have been designed for HgaI restriction marker site. The tests have been conducted first on the lapinised vaccine strain and ShiMen strain of classical swine fever virus resulting in predicted restrection patterns. Finally, the tests have been applied to 5 field isolates of different gene group analyzed by phylogenetic study. The result showed that only HCLV strain gene can be cut to 2 fragment by Hgal , and ShiMen strain and 5 field isolates cant be cut At the same time the sensitivity and specificity of nest RT-PCR have been tested. The sensitivity is 0. 2MLD. The specific fragment of BDV and BVDV were not obtained by the nest RT-PCR. These results showed that the development of the nest RT-PCR/restriction tests is very important for the control and perish of classical swine fever in china.