Aspergillus niger as the Source of Ochratoxin A of Contaminated Pyrus communis in Taif Market

Fruits are one of the most important agricultural products that supply the body with vitamins and essential minerals elements, but it is contaminated by fungi during the period of growth, harvesting and storage. A. niger is one of the species that grows on the fruit during the period of storage, and secretes mycotoxins especially ochratoxin A. This study was conducted with the purpose of isolating and identifying different strains of A. niger from 20 samples of pear collected from Taif markets and to determine the ability of these strains to produce OTA. It was observed that showed that out of 20 pear samples collected, 19 samples were detected to be contaminated with different strains of A. niger and the strains were able to produce OTA. From 27 isolates of A. niger which was used to test the ability of production OTA, 10 strains only produced OTA. The range of OTA in all strains were 0.18 to 9.5 ppb. Representative 27 strains of ochratoxigenic and non ochratoxigenic black Aspergilli isolated were subjected for detection of ochratoxin biosynthesis genes, by using two sets of primer for two genes involved in ochratoxin biosynthetic pathway. Bands of the fragments of PKS15C-MeT and PKS15KS genes visualized at 998 and 776 bp, respectively. Whereas, the presence of four tested genes is not sufficient marker for differentatin between aflatoxigenic and non aflatoxigenic isolates.

Luliconazole, a New Antifungal, vs Amphotericin B, Voriconazole, Posaconazole and Caspofungin against Clinical and EnvironmentalAspergillusNigri Complex

ABSTRACTBlack Aspergilli are,the most causes of aspergillosis andAspergillus niger and A. tubingensis are two more frequently isolates. Although, amphotericin B was a gold standard for the treatment of invasive fungal infection for several decades, it replaced by several new antifungals. Furthermore, a novel antifungal, luliconazole, appears to offer the potential for improved therapy for aspergillosis. The aim of the present study was to compare the effect of a novel antifungal agent, luliconazole, with classical antifungalagainst clinical and environmental strains of black Aspergilli. Sixty seven strains of black Aspergilli were identified using morphological and molecular tests (β-Tubulin gene). Antifungal susceptibility test was applied according to CLSI M38 A2. The results were reported as MIC range, MIC50, MIC90and MICGM. In the present study,A. nigerwas the common isolate followed by,A. tubingensisand 54.1% (clinical) and 30% (environmental) of isolates were resistant to caspofungin. The highest resistant rate was found in amphotericin B for both clinical (86.5%) and environmental (96.7%) strains. Clinical strains ofAspergilluswere more sensitive to voriconazole (86.7%) than environmental strains (70.3%). On the other hand, 83.8% of clinical and 70% of environmental isolates were resistant to posaconazole, respectively. It is found that the lowest MIC range, MIC50, MIC90, and MICGMwas attributed to luliconazole in clinical strains. In conclusion, luliconazole vs. routine antifungal is a potent antifungal forA. nigercomplexin vitro. The MIC range, MIC50, MIC90and MICGMof luliconazole against black Aspergilli were the lowest among the representative tested antifungals.