In vitro antimicrobial activity of the organic extract of Cladonia substellata Vainio and usnic acid against Staphylococcus spp. obtained from cats and dogs

Abstract

It contains several secondary metabolites with biological activity, including usnic acid, which has exhibited a wide range of biological activities. The aim of this study was to evaluate the in vitro antimicrobial activity of the organic extract of C. substellata and purified usnic acid. Initially, Staphylococcus spp., derived from samples of skin and ears of dogs and cats with suspected pyoderma and otitis, were isolated and analyzed. In antimicrobial susceptibility testing against Staphylococcus spp., 77% (105/136) of the isolates were resistant to the antimicrobials tested. In the assessment of biofilm production, 83% (113/136) were classified as producing biofilm. In genetic characterization, 32% (44/136) were positive for blaZ, no isolate (0/136) was positive for the mecA gene, and 2% (3/136) were positive for the icaD gene. The in vitro antimicrobial activity of the organic extract of C. substellata and purified usnic acid against Staphylococcus spp. ranged from 0.25mg/mL to 0.0019mg/mL, inhibiting bacterial growth at low concentrations. The substances were more effective against biofilm-producing bacteria (0.65mg/mL-0.42mg/mL) when compared to non-biofilm producing bacteria (2.52mg/mL-2.71mg/mL). Usnic acid and the organic extract of C. substellata can be effective in the treatment of pyoderma and otitis in dogs and cats caused by Staphylococcus spp.

Synergistic Effect between Usnic Acid and Polymyxin B against Resistant Clinical Isolates of Pseudomonas aeruginosa

“…It is present in different species of lichens as a product of the secondary metabolism. A series of in vitro studies demonstrated not only anti-inflammatory, antioxidant, antitumor, and antiviral properties, but also a potent antibacterial activity against mycobacteria and several Gram-positive and Gram-negative bacteria [15][16][17][18]. Along with these data, the interest in this substance has risen since it could be used as a potential antimicrobial compound.…”

Atividade antimicrobiana de fungos liquenizados ocorrentes no campus Belém da Universidade Federal do Pará, estado do Pará, Brasil

“…Estudos sobre a atividade antimicrobiana de substâncias liquênicas normalmente relatam a maior sensibilidade de bactérias Gram-positivas a extratos de diferentes espécies de fungos liquenizados 13,14,15,16,17 . Concomitante a isso, alguns autores reportaram a ineficácia dessas substâncias contra cepas de bactérias Gram-negativas 18,19 .…”

Mushrooms and Lichens the Factory of Important Secondary Metabolites: Review

“…Usnic acid was found to be a good antimicrobial agent when compared to streptomycin [90]. The (+)-usnic acid produced by Cladonia arbuscula (have antimycobacterial activity) [91], and the (-) usnic acid produced by Cladonia leptoclada (have anti-tumour activity) [92]. Odimegwu DC, et al [93] and Bhattacharjya R, et al [94], also reported that, usnic acid produced by Pseudocyphellaria glabra and Pseudocyphellaria homoeophylla have antiviral, antimicrobial and cytotoxic activities.…”