Enzymatic, antimicrobial, and leishmanicidal bioactivity of gram-negative bacteria strains from the midgut of Lutzomyia evansi, an insect vector of leishmaniasis in Colombia

Rafael J Vivero; Gustavo Bedoya Mesa; Sara M Robledo; Claudia Ximena Moreno Herrera; Gloria Cadavid-Restrepo

doi:10.1016/j.btre.2019.e00379

Enzymatic, antimicrobial, and leishmanicidal bioactivity of gram-negative bacteria strains from the midgut of Lutzomyia evansi, an insect vector of leishmaniasis in Colombia

Biotechnol Rep (Amst). 2019 Sep 18:24:e00379. doi: 10.1016/j.btre.2019.e00379. eCollection 2019 Dec.

Authors

Rafael J Vivero^{1

2}, Gustavo Bedoya Mesa¹, Sara M Robledo², Claudia Ximena Moreno Herrera¹, Gloria Cadavid-Restrepo¹

Affiliations

¹ Grupo de Microbiodiversidad y Bioprospección, Laboratorio de Biología Celular y Molecular, Universidad Nacional de Colombia, Sede Medellín, Colombia, Street 59 A # 63-20, Medellín 050003, Colombia.
² PECET (Programa de Estudio y Control de Enfermedades Tropicales), Universidad de Antioquia, Medellín, Colombia, Laboratory 632, Medellín 050003, Colombia.

Abstract

Knowledge regarding new compounds, peptides, and/or secondary metabolites secreted by bacteria isolated from the intestine of phebotominae has the potential to control insect vectors and pathogens (viruses, bacteria, and parasites) transmitted by them. In this respect, twelve Gram-negative bacteria isolated from the intestine of Lutzomyia evansi were selected and screened for their enzymatic, antimicrobial, and leishmanicidal activity. E. cancerogenus, E. aerogenes, P. otitidis, E. cloacae, L. soli, and P. ananatis exhibited enzymatic activity. 83.3% of the isolates displayed lipolytic and nitrate reductase activity and 58.3% of the isolates displayed protease activity. Hemolytic activity (17%) was identified only in E. hormaechei, and P. ananatis. E. cancerogenus, A. calcoaceticus, and P. otitidis showed cellulolytic activity. A. gyllenbergii, P. aeruginosa, and E. hormaechei showed amylolytic activity. In general, the totality of methanolic extracts exhibited antimicrobial activity, where E. hormaechei, A. calcoaceticus, and E. cancerogenus presented the highest activity against the evaluated reference bacteria strains. Cell-free supernatants (CFS_S) of the Gram-negative bacteria showed higher growth inhibitory activity against the reference Gram-positive bacteria. The CFS of A. gyllenbergii was the most active antimicrobial in this study, against S. aureus (AA_ODs = 95.12%) and E. faecalis (AA_ODs = 86.90%). The inhibition percentages of CFS against Gram-positive bacteria showed statistically significant differences (repeated measure ANOVA df= 2; F= 6.095; P= 0.007832). The E. hormaechei methanolic extract showed leishmanicidal activity (CE-50 μg/ml = 47.7 + 3.8) against metacyclic promastigotes of Leishmania braziliensis (UA301). Based on this finding, we discuss the possible implications of these bacteria in digestion and physiological processes in the Lu. evansi intestine. P. ananatis, E. cloacae, E. hormaechei, and P. otitidis were considered the most promising bacteria in this study and they could potentially be used for biological control.

Keywords: Antimicrobial screening; Bacteria-intestine interaction; Le. braziliensisenzymatic bioactivity; Leishmanicidal activity.