Antibacterial activity of medicinal plants against Leptospira spp: a literature review / Actividad antibacteriana de plantas medicinales contra Leptospiraspp: una revisión de la literatura

Leptospirosis is a zoonosis caused by bacteria of the genus Leptospira that affects animals and humans. This disease is usually treated empirically due to its prevalence in precarious areas without basic sanitation. The use of medicinal plants in less industrializedsocieties has been one of the main therapeutic resources available. Considering the need to use these natural resources to combat leptospirosis in areas of socioeconomic vulnerability, this study aimed to review the literature on the use of plants with medicinal potential in the treatment of leptospirosis. The results showed that even though leptospirosis is a common disease in communities lacking basic sanitation and economic development, the number of studies on the use of plants with medicinal potential is scarce. Most of these studies come from India, and all plants investigated between 2012 and 2020 had antileptospiral action.

La leptospirosis es una zoonosis causada por bacterias del género Leptospira que afecta a animales y humanos. Esta enfermedad suele ser tratada empíricamente debido a su prevalencia en zonas precarias sin saneamiento básico. El uso de plantas medicinales en las sociedades menos industrializadas ha sido uno de los principales recursos terapéuticos disponibles. Considerando la necesidad de utilizar estos recursos naturales para combatir la leptospirosis en áreas de vulnerabilidad socioeconómica, este estudio tuvo como objetivo revisar la literatura sobre el uso de plantas con potencial medicinal en el tratamiento de la leptospirosis. Los resultados mostraron que a pesar de que la leptospirosis es una enfermedad común en comunidades que carecen de saneamiento básico y desarrollo económico, el número de estudios sobre el uso de plantas con potencial medicinal es escaso. La mayoría de estos estudios provienen de India, y todas las plantas investigadas entre 2012 y 2020 tuvieron acción antileptospirales.

Immune strategies using single-component LipL32 and multi-component recombinant LipL32-41-OmpL1 vaccines against leptospira

Genes encoding lipoproteins LipL32, LipL41 and the outer-membrane protein OmpL1 of leptospira were recombined and cloned into a pVAX1 plasmid. BALB/c mice were immunized with LipL32 and recombined LipL32-41-OmpL1 using DNA-DNA, DNA-protein and protein-protein strategies, respectively. Prime immunization was on day 1, boost immunizations were on day 11 and day 21. Sera were collected from each mouse on day 35 for antibody, cytokine detection and microscopic agglutination test while spleen cells were collected for splenocyte proliferation assay. All experimental groups (N = 10 mice per group) showed statistically significant increases in antigen-specific antibodies, in cytokines IL-4 and IL-10, as well as in the microscopic agglutination test and splenocyte proliferation compared with the pVAX1 control group. The groups receiving the recombined LipL32-41-OmpL1 vaccine induced anti-LipL41 and anti-OmpL1 antibodies and yielded better splenocyte proliferation values than the groups receiving LipL32. DNA prime and protein boost immune strategies stimulated more antibodies than a DNA-DNA immune strategy and yielded greater cytokine and splenocyte proliferation than a protein-protein immune strategy. It is clear from these results that recombination of protective antigen genes lipL32, lipL41, and ompL1 and a DNA-protein immune strategy resulted in better immune responses against leptospira than single-component, LipL32, or single DNA or protein immunization.

In vitro susceptibilities of Leptospira spp. and Borrelia burgdorferi isolates to amoxicillin, tilmicosin, and enrofloxacin

Antimicrobial susceptibility testing was conducted with 6 different spirochetal strains (4 strains of Leptospira spp. and 2 strains of Borrelia burgdorferi) against 3 antimicrobial agents, commonly used in equine and bovine practice. The ranges of MIC and MBC of amoxicillin against Leptospira spp. were 0.05 - 6.25 microgram/ml and 6.25 - 25.0 microgram/ml, respectively. And the ranges of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of amoxicillin against B. burgdorferi were 0.05 - 0.39 microgram/ml and 0.20 - 0.78 microgram/ml, respectively. The ranges of MIC and MBC of enrofloxacin against Leptospira spp. were 0.05 - 0.39 microgram/ml and 0.05 - 0.39 microgram/ml, respectively. Two strains of B. burgdorferi were resistant to enrofloxacin at the highest concentration tested for MBC (> or = 100 microgram/ml). Therefore, the potential role of tilmicosin in the treatment of leptospirosis and borreliosis should be further evaluated in animal models to understand whether the in vivo studies will confirm in vitro results. All spirochetal isolates were inhibited (MIC) and were killed (MBC) by tilmicosin at concentrations below the limit of testing (< or = 0.01 microgram/ml).