Silver nanoparticles combined with ketoconazole as a promise to improve the pityriasis versicolor treatment

MUSSIN J; ROJAS F; SOSA MA; ALEGRE L; GIUSIANO G

Salvador de Bahía

Congreso; 17th Infocus and 1st ISHAM Latin American Congress; 2019

The aim of this work was to study the in vitro inhibitory activity of silver nanoparticles (AgNP) obtained by green synthesis, alone and in combination with ketoconazole (KTZ) against clinical isolates of Malassezia globosa.AgNP of 15 nm in diameter, previously characterized by physical and chemical methods, synthesized from an aqueous extract of Acanthospermum australe (Loefl.) Kuntze were used. In order to evaluate the inhibitory activity of AgNP and KTZ, the minimum inhibitory concentrations (MIC) against 9 M. globosa clinical isolates and the reference strain CBS7966 were determined by broth microdilution method in accordance with the CLSI document M27-A3, with modifications. To evaluate the effect of the combination of AgNP with KTZ, fractional inhibitory concentration index (FICi) were determined using the checkerboard microdilution method. AgNP showed MIC values in the range of 0.125 - 0.5 µg / mL, mode of 0.125 µg / mL while KTZ showed a range ≤ 0.03 - 0.06 µg / mL and mode of 0.03 µg / mL. FICi values obtained showed synergistic effect (FICi ≤ 0.5) between AgNP and KTZ against M. globosa strains tested.M. globosa is a lipophilic and lipid-dependent yeast, considered by some authors as the main causative agent of pityriasis versicolor (PV). Topical antifungal medications are the first-line treatment and KTZ is one of the most active against Malassezia.However, antifungal therapies for PV are not always effective, have a high recurrence rate and patient application compliance may be affected by multiple or laborious applications, especially in cases where large body areas are affected. In recent years, along with the advances in nanotechnology and the incentive to find new antifungal drugs, there has been a growing interest in the utilization of nanoparticles for the treatment of fungal infections. Within the different types of metal nanoparticles, AgNP have stood out for their considerable antimicrobial activity and lower toxicity for animal cells. In addition, have been shown that AgNP accumulates with a more concentration in hair follicles and sebaceous glands, where Malassezia is more frequently located; besides, having the ability to release metallic silver steadily over a period of days or even weeks. The low MIC values with restricted range obtained for AgNP against M. globosa and the synergistic effect with KTZ demonstrated in this work, open the door for development products based in AgNP-KTZ to improve the topical therapy of PV, reduced number of applications necessary and, also, to prevent recurrence.