18S rRNA gene sequencing for environmental aflatoxigenic fungi and risk of hepatic carcinoma among exposed workers

Abstract

Aspergillus exposure causes an increase in aflatoxin (AF) levels among exposed workers thereby increasing their risk of developing hepatocellular carcinoma (HCC). This study attempted to determine the presence of airborne aflatoxigenic fungi in environment of waste water treatment plant (WWTP); and study the hepatic cancer risks among exposed workers, emphasizing the role of glutathione S-transferases (GST) gene polymorphism protecting against the risk of hepatic cancer development due to exposure to AFs. The study isolated and identified different Aspergillus species producing AFs in air samples from WWTP sites using 18S ribosomal ribonucleic acid (18S rRNA) gene sequencing technique. GST gene polymorphisms were genotyped using polymerase chain reaction–restriction fragment length polymorphism (PCR-RFLP). A significant increase in blood AF levels was found among WWTP exposed workers. The occurrence of GSTT1& M1 gene polymorphism in 6% of the workers was accompanied by significant decrease in the levels of AFs and alpha fetoprotein (AFP). In conclusion, Aspergillus-producing AFs were found in air of WWTP. Continuous exposure to AF-producing fungi caused elevated AF-levels in exposed workers. However only workers with heterozygous GSTT1& M1 genotypes can detoxify AFs, thereby decreasing the risk of HCC development among exposed workers.

Keywords:

• Aspergillus
• 18S rRNA gene sequence
• aflatoxin
• glutathione S-transferases gene polymorphism
• alpha fetoprotein

Declaration of conflicting interests

The authors declare that they have no conflict of interest.

Data availability statement

The datasets analyzed during the current study are available from the corresponding author on reasonable request.

Ethical approval

Approval of the Ethical Committee of the National Research Center was taken before the study (Registration number 17085).

Acknowledgment

The authors express their sincere thanks to Academy of Scientific Research and Technology (ASRT). As this work was funded by Academy of Scientific Research and Technology (ASRT) (2017–2020), and to the mangers of Abu-Rawash WWTP and the workers in it for their cooperation to finish this work.

Additional information

Funding

This work was funded by the Academy of Scientific Research and Technology (ASRT) (2017–2020), the funded project (ID:1475) titled “Improving environmental and health conditions for workers in Abu-Rawash wastewater treatment plant and remediation of pollution resources at El-Rahawy Drain”.