In vitro Susceptibility of Clinical Aspergillus Species to Some Antifungal Agents

Aspergillus species are regularly involved in human broncho-pulmonary diseases, mainly in immunocompromised patients. The essential oils extracted from three different plants were tested for their inhibitory effect on the growth of five pathogenic Aspergilli including Aspergillus flavus, Aspergillus fumigatus, Aspergillus niger, Aspergillus versicolor and Aspergillus terreus which are pathogens with clinical importance. The results of the antimicrobial tests showed that the isolated essential oils inhibited the growth of Aspergillus species to varying degrees. The Ocimum basilicum oil completely inhibited the mycelial growth and spore germination of A. terreus and A. fumigatus at 200 and 250 ppm. In addition, this oil showed a very strong antifungal activity against the mycelial growth and spore germination of A. flavus and A. versicolor with 97.7, 97.5, 91.2 and 93.5%, respectively, when compared with control. The essential oil extracted from Eucalyptus globulus also exhibited significant antifungal activity against the Aspergillus species tested. This oil completely inhibited the mycelial growth and spore germination of A. fumigatus. Conversely, Nigella sativa oil exhibited moderate inhibitory activity against all the tested Aspergillus species. The present study supports the proposition that plant essential oils may have a role in both pharmaceutical and agricultural practices.