Fumonisin B1 contamination of cereals and risk of esophageal cancer in a high risk area in northeastern Iran.

INTRODUCTION: Fumonisin B1 (FB1) is a toxic and carcinogenic mycotoxin produced in cereals due to fungal infection. This study was conducted to determine FB1 contamination of rice and corn samples and its relationship with the rate of esophageal cancer (EC) in a high risk area in northeastern Iran. METHODS: In total, 66 rice and 66 corn samples were collected from 22 geographical subdivisions of Golestan province of Iran. The levels of FB1 were measured for each subdivision by thin layer and high pressure liquid chromatographies. The mean level of FB1 and the proportions of FB1 contaminated samples were compared between low and high EC-risk areas of the province. RESULTS: The mean of FB1 levels in corn and rice samples were 223.6 and 21.6 µg/g, respectively. FB1 contamination was found in 50% and 40.9% of corn and rice samples, respectively. FB1 level was significantly higher in rice samples obtained from high EC-risk area (43.8 µg/g) than those obtained from low risk area (8.93 µg/g) (p-value=0.01). The proportion of FB1 contaminated rice samples was also significantly greater in high (75%) than low (21.4%) EC-risk areas (p-value=0.02). CONCLUSION: We found high levels of FB1 contamination in corn and rice samples from Golestan province of Iran, with a significant positive relationship between FB1 contamination in rice and the risk of EC. Therefore, fumonisin contamination in commonly used staple foods, especially rice, may be considered as a potential risk factor for EC in this high risk region.

Disseminated, fatal Trichosporon asahii infection in a bone marrow transplant recipient.

Trichosporon asahii is the most important species regularly isolated from systemic mycoses and shows a predilection for hematogenous dissemination. This report describes the first fatal case of disseminated trichosporonosis caused by T. asahii in a patient with familial aplastic anemia (AA). An 11-year-old girl with familial AA received chemoradiotherapy and immunosuppressive therapy for bone marrow transplantation. She was neutropenic and suffered from fever, cough, and severe mouth ulcers. T. asahii was repeatedly demonstrated by appropriate morphological and physiological characteristics, i.e., arthroconidium formation, urease activity, and assimilation of carbon and nitrogen compounds. T. asahii was found in samples of sputum, nose, and mouth ulcers by direct microscopy and culturing. Furthermore, postmortem histopathology study revealed vast tissue invasion of fungal hyphae characteristic of Trichosporon in the lung and liver. Disseminated trichosporonosis should be suspected in immunocompromised patients when a febrile condition does not improve after prolonged treatment with broad-spectrum parenteral antibiotics.

Fumonisin production by Fusarium species isolated from freshly harvested corn in Iran.

Fifty-one strains of Fusarium verticillioides and F. proliferatum isolated from corn collected from four different geographic areas in Iran, namely Fars, Khuzestan, Kermanshah and Mazandaran (an endemic oesophageal cancer (OC) area) were evaluated for their ability to produce fumonisins B1 (FB1), B2 (FB2) and B3 (FB3) in corn culture. Fumonisin levels were determined by high-performance liquid chromatography. All tested strains of F. verticillioides and F. proliferatumproduced fumonisins within a wide range of concentrations, 197-9661 microg/g, 18-1974 microg/g, and 21-1725 microg/g for FB1, FB2, and FB3, respectively. The highest mean concentrations of FB1, FB2, and FB3 were 3897, 806 and 827 microg/g, respectively. Overall, 61% of the F. verticillioides and F. proliferatum strains produced higher levels of FB3 than FB2. The mean ratios of FB1:FB2, FB1:FB3 and FB1:total fumonisins were 8, 7 and 0.7 for F. verticillioides and 5.7, 10.7 and 0.7 for F. proliferatum, respectively. Significant differences in some of the meteorological data (rainfall, relative humidity and minimum temperature) from the four provinces were observed. Fumonisin levels produced by F. verticillioides strains isolated from Khuzestan province (tropical zone) were significantly (P < 0.01) higher than the other three provinces. This is the first report of the fumonisin-producing ability of F.verticillioides and F. proliferatum strains isolated from corn harvested from different geographic areas in Iran.

Mycoflora of Iranian maize harvested in the main production areas in 2000.

Maize is one of the most important cereals produced in, and imported into, Iran. The incidences of seed-borne fungi were determined in Iranian maize harvested in 2000 from four major production areas with different climatic conditions, namely Fars, Khuzestan, Kermanshah and Mazandaran provinces. This is the first study to compare the mycoflora of maize in the aforementioned areas. Mycological analyses showed a predominance of Fusarium species (38.5%), followed by Aspergillus species (8.7%), Rhizopus species (4.8%), Penicillium species (4.5%), Mucor species (1.1%), and four other fungal genera. Fusarium verticillioides was the most prevalent species (83% of Fusarium isolates and 52% of the total isolations), with the highest incidence in Mazandaran (59%), a region of Iran with the highest rainfall and relative humidity, high rate of esophageal cancer (EC) and high levels of fumonisins in maize. Aspergillus flavus was the most widely recovered Aspergillus species and 38% of samples were contaminated with this potentially aflatoxigenic fungus. The incidence of A. flavus was highest in Kermanshah, the province with lowest mean minimum temperature. Penicillium species were seen in all the samples and Fars had the highest incidence, with highly significant differences when compared to the other three provinces. Diplodia species were not isolated from any of the samples examined.