Carbon utilization phenome of Leptospira interrogans serovar Manilae strain K64

Background: Leptospirosis, an acute febrile disease caused by the pathogenic species of genus Leptospira, is one of the neglected emerging zoonoses that is of global public health concern. The recent genus-wide sequencing of Leptospira isolates led to the need for better understanding of the complex metabolic mechanisms of this organism. However, majority of the published studies on Leptospira metabolism were still the pioneering works of Baseman and Cox in the 60’s and their contemporaries. Knowledge on the carbon sources that supports the growth of a Leptospira species will not only contribute to the limited metabolic studies but will further support the reported genes and metabolic pathways of this organism. Objective:  Thus, this study aimed to describe the carbon utilization phenome of Leptospira interrogans serovar Manilae strain K64, one of the dominantly circulating pathogenic Leptospira in the Philippines. Methods:  A previously optimized BiologTM Gen III sole carbon utilization phenotype microarray assay protocol for leptospires was adapted. Results:  L. interrogans serovar Manilae strain K64 showed utilization of 29 carbon sources belonging to sugars and sugar derivatives, amino acids, methyl ester, carboxylic acid and fatty acids. These were N-acetyl-β-D-mannosamine, N-acetyl-D-galactosamine, N-acetyl neuraminic acid, D-fructose, D-galactose, 3-methyl glucose, D-fucose, L-fucose, L-rhamnose, inosine, D-fructose-6-phosphate, D-gluconic, D-glucuronic acid, glucuronamide, D-saccharic acid, D-aspartic acid, D-serine,  L-alanine, L-arginine,  L-histidine, L-pyroglutamic acid, L-serine, D-lactic acid methyl ester, citric acid, D-malic acid, L-malic acid, alpha ketoglutaric acid, alpha ketobutyric acid, and acetoacetic acid.  Discussion and Conclusion:  The carbon sources utilized by L. interrogans serovar Manilae strain K64 agreed well with the identified genes and metabolic pathways among Leptospira species.  Moreover, these 29 carbon sources have been previously reported to be associated in the biosynthesis of peptidoglycan, lipopolysaccharide, histidine, sulfur, amino acids, and isoleucine and in other metabolic pathways such as glycolysis, pentose-phosphate, pyruvate and fatty acid in Leptospira spp.