The in vitro and in vivo effects of Lucilia sericata larval secretions on Leishmania major.

The emerging of drug resistant against Leishmania parasites prompts scientists to seek for novel therapeutic strategies against theses infectious protozoan parasites. Among different strategies, the use of larvae secretions could be suggested as a possible therapy with low side effects. Accordingly, the current study evaluated the in vitro and in vivo effects of Lucilia sericata larval secretions on Leishmania major, the causative agent of cutaneous leishmaniasis (CL). After preparation of L. sericata larval stages (L2 and L3) secretions, the potential effects of secretions were evaluated against L. major promastigotes and amastigotes (in vitro) using MTT assay. The cytotoxicity effects of secretions were also checked on uninfected macrophages. In addition, in vivo experiments were also conducted to investigate the effects of larvae's secretions on the CL lesions induced in the BALB/c mice. Although the increased concentration of larvae secretions exhibited a direct effect on the promastigotes proliferation (viability), contrarily, L2 secretions at a concentration of 96 µg/ml represented the highest inhibitory effect on parasite (amastigotes) burden in infected macrophages. Interestingly, L3 secretions > 60 µg/ml induced inhibitory effects on amastigotes. The results relevant to the cytotoxicity effects of L2 and L3 secretions on uninfected-macrophages showed a dose dependent correlation. In vivo results were also significant, compared to the positive control group. This study suggested the plausible inhibitory effects of L. sericata larvae's secretions on the L. major amastigotes and CL lesions progression. It seems that the characterization of all effective components/proteins in the larvae secretions and their specific targets in parasite structure or in cell (macrophage) responses could further reveal more details regarding the anti-leishmanial properties of these compounds.

Evaluation of Exoenzyme Activities, Biofilm Formation, and Co-hemolytic Effect in Clinical Isolates of Candida parapsilosis Species Complex.

Candida parapsilosis species complex is considered as important emerging pathogens and little is known about their pathogenicity factors and co-hemolytic activity with different bacteria species. The aim of this study was to determine in vitro exoenzyme activities, biofilm formation, and co-hemolytic effect of different bacteria species on clinical C. parapsilosis complex isolates. In total, 67 C. parapsilosis complex isolates consist of C. parapsilosis sensu stricto 63/67 and Candida orthopsilosis 4/67 were used in this study. To determine the hemolytic activity of these species, Sabouraud dextrose sheep blood agar was used. Evaluation of the CAMP-like phenomenon carried out in the presence of Staphylococcus aureus, Staphylococcus saprophyticus, Staphylococcus epidermidis, and Streptococcus agalactiae. Tube test method with ethylenediaminetetraacetic acid-rabbit plasma was used to determine coagulase activity, and biofilm formation was assessed by the tube method in assist of Sabouraud glucose broth (8%) medium. Fisher's exact tests were used for data statistical analysis. Sixty-six of 67 (98.5%) and 3/67 (4.5%) of the species showed hemolysin and coagulase activity, respectively. Fifty-five of 67 (82.1%) of species had ability for biofilm formation, and none of the samples exhibited co-hemolytic effect in the presence of four mentioned bacteria. No significant difference was found between the level of enzyme production and biofilm formation among the isolates.