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. 2025 Jun 28;29(5):104556.
doi: 10.1016/j.bjid.2025.104556. Online ahead of print.

Single nucleotide polymorphisms associated with benzimidazole resistance of the β-tubulin isotype 1 gene in Ascaris lumbricoides isolated in South Africa

Teniel Ramkhelawan  1 , Pragalathan Naidoo  1 , Zilungile L Mkhize-Kwitshana  2
Affiliations

Single nucleotide polymorphisms associated with benzimidazole resistance of the β-tubulin isotype 1 gene in Ascaris lumbricoides isolated in South Africa

Teniel Ramkhelawan et al. Braz J Infect Dis. .

Abstract

Background: Ascariasis is a parasitic infection caused by Ascaris lumbricoides and infects over 1.2 billion people worldwide. Benzimidazole (BZ) drugs remain the standard treatment in large-scale deworming programs globally. The prevalence of Single Nucleotide Polymorphisms (SNPs) in the β-tubulin gene of A. lumbricoides (F200Y, E198A and F167Y) is increasing due to the widespread use of BZ drugs.

Aim: To investigate the prevalence of the above-mentioned SNPs in a South African adult population.

Methods: This was a sub-study of the main cross-sectional study with participants (n = 414) who had been recruited from five public health clinics in the peri‑urban areas South of Durban, KwaZulu-Natal, South Africa. For the current study, a purposive selection of 20 stool samples that were positive for A. lumbricoides eggs was made. A. lumbricoides worm extracts (n = 4) were used as a positive control. Sanger sequencing and RFLP-PCR were used to identify the presence of mutations.

Results: No mutations were detected, and all genotypes observed at codons F167Y, E198A and F200Y were the homozygous wild-type genotype.

Conclusion: Although no mutations were found in this small study, the potential occurrence of mutations in a larger sample subset cannot be ruled out.

Keywords: A. lumbricoides, β-tubulin isotype 1 gene; Benzimidazole drug resistance; Single nucleotide polymorphisms; Treatment efficacy.

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Conflict of interest statement

Conflicts of interest The authors declare no conflicts of interest.

Figures

Fig. 1
Fig. 1
Agarose gel electrophoresis image of the β-tubulin isotype 1 gene of A. lumbricoides from the four positive control worm samples after RT-PCR. Lane M contains the 100 bp molecular weight marker, Lane 1 contains the negative control, lanes 2 – 5 contains the β-tubulin isotype 1 gene (564 bp) positive samples.
Fig. 2
Fig. 2
Sanger sequencing of the positive control PCR amplicons of the β-tubulin isotype 1 gene of A. lumbricoides worm samples showing a 99 % sequence match (accession number EU814697.1) and sequence alignment to the β-tubulin isotype-1 mRNA, partial CDS of A. lumbricoides on NCBI BLAST.
Fig. 3
Fig. 3
Agarose gel electrophoresis image of the F200Y codon in the β-tubulin isotype 1 gene of A. lumbricoides after RFLP-PCR. Lane M contains the 100 bp molecular weight marker, lane 1 contains the positive control sample, lane 2 contains the negative control, lanes 3 – 22 contains the 92 bp F200Y RFLP-PCR products that are observed to be the homozygous wild-type genotypes (T/T genotype).
Fig. 4
Fig. 4
Agarose gel electrophoresis image of the F167Y codon in the β-tubulin isotype 1 gene of A. lumbricoides after RFLP-PCR. Lane M contains the 100 bp molecular weight marker, lane 1 contains the negative control sample, lane 2 contains the positive control sample, lanes 3 – 22 contains the 543 bp and 65 bp F167Y RFLP-PCR products that are observed to be the homozygous wild-type genotype (T/T genotype).
Fig. 5
Fig. 5
Agarose gel electrophoresis image of the E198A codon in the β-tubulin isotype 1 gene of A. lumbricoides after RFLP-PCR. Lane M contains the 100 bp molecular weight marker, lane 1 contains the positive control sample, lane 2 contains the negative control sample, lanes 3 – 22 contains the 608 bp E198A RFLP-PCR products that are observed to be the homozygous wild-type genotype (A/A genotype).
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References

    1. Naidoo P., Ghazi T., Chuturgoon A.A., Naidoo R.N., Ramsuran V., Mpaka-Mbatha M.N., et al. SARS-CoV-2 and helminth co-infections, and environmental pollution exposure: an epidemiological and immunological perspective. Environ Int. 2021;156:1–14. - PMC - PubMed
    1. Casulli A. New global targets for NTDs in the WHO roadmap 2021-2030. PLoS Negl Trop Dis. 2021;15 - PMC - PubMed
    1. World Health Organization (WHO) World Health Organization 2019. Soil-transmitted helminth infections; Geneva, Switzerland: 2020. Global Atlas of Helminth Infections: Soil-transmitted helminths.https://www.who.int/news-room/fact-sheets/detail/soil-transmitted-helmin... [Accessed 2023 November 20]
    1. Pullan R.L., Smith J.L., Jasovsky M., Brooker S. Global, regional, and national estimates of soil-transmitted helminth soil prevalence in 2010. PLOS Neg Trop Dis. 2014;8:e2657.
    1. Centers For Disease Control. Parasites – Ascariasis. 2020. https://www.cdc.gov/parasites/ascariasis/index.html#:∼:text=An20estimate... [Accessed 2023 November 20].

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