Comparative analysis of routine parasitological methods for recovery of cysts, molecular detection, and genotyping of Giardia duodenalis.

Abstract

In order to improve the diagnosis of giardiasis, fecal samples (high/medium/low concentration of cysts) were processed by the parasitological methods used in the routine: Faust, Lutz e Ritchie modified (replacement of formaldehyde by distilled water). The cysts were quantified; the DNA was extracted and amplified by semi-nested PCR (GDH gene). Fifteen clinical samples were analyzed to validate the study by PCR-RFLP. The results showed that the parasite was only detected and genotyped correctly when samples from children with high, medium, and low parasitic load, belonging to genotype AII, were processed by the modified Ritchie method, different from what was observed for the other methods used in laboratory routine (Faust and Lutz). The modified Ritchie method proved to be more suitable, recovering a greater number of cysts from samples, regardless of parasitic load, which reduces the chance of false negative results and has epidemiological repercussions since individuals with low parasite load are usually asymptomatic and the main disseminators of this infection.

• Authors: Renata Coltro Bezagio, Cristiane Maria Colli, Liara Izabela Lopes Romera, Caroline Rodrigues de Almeida, Érika Cristina Ferreira, Mônica Lúcia Gomes
• Journal: European journal of clinical microbiology & infectious diseases : official publication of the European Society of Clinical Microbiology (Eur J Clin Microbiol Infect Dis) Vol. 40 Issue 12 Pg. 2633-2638 (Dec 2021) ISSN: 1435-4373 [Electronic] Germany
• PMID: 34059933 (Publication Type: Comparative Study, Journal Article)
• Copyright: © 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.

Chemical References

• Protozoan Proteins

Topics

• Child, Preschool
• Feces (parasitology)
• Female
• Genotype
• Genotyping Techniques (methods)
• Giardia lamblia (genetics, growth & development, isolation & purification)
• Giardiasis (diagnosis, parasitology)
• Humans
• Infant
• Life Cycle Stages
• Male
• Molecular Diagnostic Techniques (methods)
• Parasite Load
• Polymerase Chain Reaction (methods)
• Protozoan Proteins (genetics)