Antiviral effect of Glycine coated Iron oxide nanoparticles iron against H1N1 influenza A virus

Background: Salmonella enterica ser. Typhi is the causative agent of the clinical condition called typhoid fever that results after an incubation period of 10 to 15 days following infection. The main line of treatment of typhoid fever includes antibiotics such as fluoroquinolones and aminoglycosides; however, several studies have reported decreased susceptibilities of fluoroquinolones among Salmonella spp isolated from human infections. Thus, this necessitates the studies to explore alternative or adjunct therapeutic agents. Methods & Materials: In this study we isolated and screened the antimicrobial potential of 92 vaginal lactic acid bacteria from healthy women against S. enterica ser. Typhi MTCC 733 by using agar gel diffusion assay. Further, the susceptibility of S. enterica to various antibiotics and the synergistic activity of the culture supernatant (CS) of the isolate 12a along with antibiotics was determined by using Kirby Bauer disk diffusion and chequerboard titration methods, respectively. Results: The isolate no. 12a, identified as Enterococcus spp. by using physico-chemical characterisation showed broad spectrum antimicrobial activity against many Gram-negative pathogens including S. enterica MTCC733. The antimicrobial activity of the CS of 12a was proteinaceous in nature and lost its activity on treatment with pepsin, proteinase K and papain. The minimum inhibitory concentration of the CS was 2133 AU/ml and was stable over a wide pH range of 3-11. Further, the antimicrobial activity of the CS was lost at 100◦C; 1 hr treatment. The susceptibility of S. enterica to various antibiotics was determined and it showed reduced susceptibilities to many fluoroquinolones and aminoglycosides. Chequerboard titration assay showed that CS of 12a synergised antimicrobial activities of the antibiotics belonging to the classes fluoroquinolones, aminoglycosides and -lactam against S. enterica. Conclusion: In conclusion, the study indicates the potential of the probiotic strains of enterococci as adjunct therapeutic agent against resistant forms of S. enterica.