First multilocus sequence typing (MLST) of Giardia duodenalis isolates from humans in Romania

Abstract

Background: Giardia duodenalis is one of the most prevalent and highly diverse human parasites, encompassing a complex of eight genetically distinct assemblages, each further divided into sub-assemblages. While in recent years, G. duodenalis genotype distribution patterns in humans have been intensely studied, there is still very little information available on the diversity of Giardia genotypes and sub-assemblages infecting people in Romania. In the present study, we investigated the genetic diversity of Giardia duodenalis in asymptomatic patients from Romania. Methods: Over an 11-month period, human feces from 7805 healthy adults were screened by microscopic analysis for G. duodenalis cysts during their obligatory periodic checkups. DNA extraction was performed from microscopicpositive fecal samples, followed by multilocus sequence typing of four genetic loci of the ITS region, gdh, tpi and bg genes, followed by DNA sequencing and phylogenetic analysis. Statistical analysis was performed using EpiInfo 2000 software. Results: The prevalence of giardiasis in the present study was 0.42% (33/7805). Twenty-three samples (76.67%) were successfully genotyped at each locus. The bg and tpi genes had the highest typing success rate (100%). The identified assemblages were assemblage A in 27 cases (subtypes A2 and A3), and B in 3 cases. Conclusions: To our knowledge, the present study is the first report of multilocus sequence typing of G. duodenalis isolated from humans in Romania. The present results may shed light on G. duodenalis infection in humans at a regional and national level, thus increasing awareness against this parasitic infection.

The controversies surrounding Giardia intestinalis assemblages A and B

“…Assemblage B infections have a higher parasitic load and increased rate of cyst shedding which would explain the higher detection rates in comparison to assemblage A infections ( Kohli et al, 2008 ). Yet higher rates of assemblage A infections have been observed in countries such as Brazil ( Souza et al, 2007 ), Ethiopia ( Damitie et al, 2018 ), Iran ( Kasaei et al., 2018 ; Mahmoudi et al, 2020 ), New Zealand ( Winkworth et al., 2008 ), Syria ( Skhal et al., 2017 ) and Romania ( Costache et al., 2020 ). Due to limited molecular epidemiological studies of giardiasis in humans, an accurate geographical pattern for individual G. intestinalis assemblages cannot be concluded.…”

“…There is speculation that mixed assemblage infections are being underreported due to the preferential amplification of one assemblage over the other depending on the primer set being used ( Wielinga & Thompson, 2007 ). Moreover, primers used for typing G. intestinalis not only differ in their specificities (see Table 1 ) but have been reported to have variable amplification success rates ( Costache et al., 2020 ; Chourabi et al., 2021 ; Iwashita et al, 2021 ).…”

“…MLST studies that have utilised the AL3543/AL3546 primer set have observed low amplification rates for tpi genes when comparing to bg and gdh ( Chourabi et al., 2021 ; Iwashita et al, 2021 ). Yet another MLST study using the same primers found that typing at the tpi gene had the highest amplification success compared to the gdh and ITS regions ( Costache et al., 2020 ). Several factors may be causing this lack of reliability, including the DNA yield and method of DNA extraction, as well as the possibility of DNA contaminants and inhibitors ( Faria et al., 2017 ).…”

Genetic Diversity and Prevalence of Giardia duodenalis in Qatar

“…The increased percentage of assemblage B over A is in line with the reports from previous studies ( van der Giessen et al., 2006 ; Hijjawi et al., 2016 ; Nunes et al., 2018 ). Although most studies have reported assemblage B to be more prevalent in both developed and developing countries ( Costache et al., 2020 ; Messa et al., 2021 ), other studies have found a predominance of assemblage A ( Thompson, 2000 ; Asher et al., 2016 ). It was suggested that the relatively high percentage of assemblage B may be attributable to the technical tools used to detect G. duodenalis.…”

Correction to: First multilocus sequence typing (MLST) of Giardia duodenalis isolates from humans in Romania

“…Following publication of the original article [ 1 ], it was brought to our attention that incorrect primers information had been provided in Table 1 .…”