Anti-Pathogenic and Technological Traits of Coagulase-Negative Staphylococci Isolated from Koozh, a Fermented Food Product of South India

Abstract

ABSTRACTThe aim of this study was to assess the biopotency of fermented food product Koozh associated coagulase-negative staphylococci (CNS) against Mycobacterium tuberculosis H37Rv and non-mycobacterial pathogens, and to document some technologically relevant attributes. The anti-tubercular property of six CNS strains was exhibited using luciferase reporter phage assay. All strains revealed pronounced mycobactericidal property in terms of higher percentage of relative light unit reduction (> 90%). The antagonistic role of CNS strains against non-mycobacterial pathogens was evaluated using agar well diffusion assay. Staphylococcus hominis strain MANF2 was found to be the most effective against Staphylococcus aureus MTCC 96 and Yersinia enterocolitica MTCC 840 with arbitrary units of 1600.31 ± 22.3 and 1500.23 ± 22.3 AU/mL, respectively. Further, various technological attributes of staphylococci were determined using standard methodology. All strains exhibited promising carbohydrate fermentation ability at standard in vitro conditions. CNS strains were positive for exopolysaccharide production and expressed strain specific lipase activity. All the isolates lacked amylase activity and biofilm formation ability. All six CNS strains, particularly strain MANF2 exhibited significant rate of autolytic and catalase activity, and showed the potential to reduce nitrate to nitrite. Most importantly, these strains were categorized for safe utilization based on in vitro safety hazards test. Overall, the present investigation indicated the persuasive biopotency of CNS against M. tuberculosis H37Rv and non-mycobacterial pathogens, and revealed adaptable technological attributes that would make them relevant for formulation of staphylococcal starter cultures for the development of quality fermented food products.