Biogenic fabrication and characterization of silver nanoparticles using aqueous-ethanolic extract of lichen (Usnea longissima) and their antimicrobial activity

Table 1 Mean zone of inhibition (in mm)

Bacterial strains	Silver nanoparticles	Negative control*	Positive control**
Staphylococcus aureus	10.6 ± 0.50^a	6.2 ± 0.20	28.0 ± 0.89
Streptococcus mutans	6.5 ± 0.89^a	5.8 ± 0.40	29.2 ± 0.83
Streptococcus pyrogenes	15.6 ± 0.40^a	6.2 ± 0.20	29.2 ± 0.48
Streptococcus viridans	14.6 ± 0.24^a	6.2 ± 0.20	25.6 ± 0.20
Corynebacterium xerosis	13.6 ± 0.50^a	6.2 ± 0.20	22.8 ± 0.58
Corynebacterium diphtheriae	6.2 ± 0.37^a	6.2 ± 0.20	22.2 ± 0.48
Escherichia coli	20.8 ± 0.02^a	6.2 ± 0.20	26.8 ± 0.48
Klebsiella pneuomoniae	16 ± 0.31^a	6.2 ± 0.20	26.4 ± 0.24
Pseudomonas aeruginosa	7 ± 0.31^a	6.2 ± 0.20	21.8 ± 0.37

Values are expressed as mean ± SD (n = 3) and valued followed by same letter are not significantly different at the p < 0.0001as determined by Duncan’s Multiple Range Test; * indicates dimethyl sulphoxide, ** indicates standard drug (Ciprofloxacin for gram positive and Gentamicin for gram negative bacterial strains)

ISSN: 2055-7124