Antimicrobial Activities of Essential Oils against Common Hospital Fungi Species

Introduction: In hospitals and other healthcare settings the presence of airborne and sedimented fungi is an extrinsic risk factor for opportunistic infections involving both immunocompromised and non-immunocompromised persons. In hospitalized patients, it is estimated that 9% of hospital-acquired infections are caused by fungi. Lethality rate varies from 40% to 100% depending on the immunosuppression degree of stakeholders. To prevent healthcare-associated infections, the control of environmental fungal contamination through use of sanitizing/disinfecting practices is basic. However, the widespread use of common disinfectants could promote the growth of antibiotic-resistant superbugs and cause environmental harm. These aspects stimulated the search of new antimicrobial agents. The aim of this study was to evaluate the antimicrobial activity of essential oils of Mentha insularis Req., Mentha pulegium L., Mentha requienii Bentham, Artemisia caerulescens L. ssp. densiflora (Viv), Rosmarinus officinalis L. var. albiflorus, Rosmarinus officinalis L. var. lavandulescens, and Ocotea puchury major Mart. against fungi species frequently found in hospitals and potentially responsible for opportunistic mycoses. Methods: The essential oils’ antifungal activity was carried out by agar disc diffusion technique. Results: All tested essential oils are effective, though to a different degree, against both molds that yeasts assessed. The major antifungal activity was showed by Mentha oils. Particularly, Mentha requienii and Mentha insularis oils were active until 1:8 dilution against Rhodotorula spp. and 1:16 dilution against mixed molds, while M. pulegium was strongly active until 1:2 against both fungi. Conclusions: To the best of our knowledge, few or no data are available in literature on the activity of essential oils against hospital environmental isolates of fungi. Results suggest their potential application in sanitation procedures of the hospital, and in general, of the “care settings”.