Analysis of Sars-CoV-2 RBD Mutations in Khuzestan Province, Iran—A Retrospective Study, 2021

Background and Objective: One of the main reasons for the ongoing pandemic is the substitutions in the Receptor binding domain(RBD), which is involved in binding to the ACE2 receptor. Methods: Oro-nasopharyngeal swabs were collected from 41 confirmed patients between September 2020 and May 2021 to analyze the mutations of SARS-CoV-2 RBD in Khuzestan Province. Bi-Directional sequencing was used, and Mutation analysis was performed using multiple Bioinformatics tools. Results: A total of 35 Single nucleotide polymorphisms (SNPs) were observed in 26 samples. Nonsynonymous substitutions occurred only in the receptor-binding motif (RBM), which accounted for 97% of the detected mutations. 37.14% of observed mutations were N501Y. L452R, T478K, and S477N accounted for 22.86%, 20%, and 11.43% of detected substitutions, respectively. Subsequently, the S477G and Y449N were identified in only one sample. The only synonymous substitution of this study was observed in C432 of one sample. It was found that December 2020 and May 2021 could be the probable prevalence times of the Alpha and Delta variants in Khuzestan, respectively. Also, in a December 2020 sample, a mutation was detected that was only seen in Epsilon among the Variants of interest and Variants of concern. Conclusion: Our study showed the existence of some Omicron-related mutations before the emergence of this variant in Khuzestan Province, Iran. In addition, it Strengthened the possibility of unconfirmed variants, such as Epsilon entering Iran. It also provided a reference for studies that need to be aware of the circulating variants in Iran.