Molecular Characterization of Giardia lamblia: First Report of Assemblage B in Human Isolates from Rio de Janeiro (Brazil)

Abstract

BackgroundDespite the high prevalence of giardiasis, the genetic characterization of Giardia lamblia has been poorly documented in Brazil and molecular epidemiology research has only been conducted in the last few years. The aim of this study was to determine the prevalence of different G. lamblia assemblages and detect mixed infections among patients with giardiasis.Methods and Principal FindingsThe cross-section survey was conducted among patients attending the FIOCRUZ in Rio de Janeiro. In order to discriminate the genetic assemblages/sub-assemblages, G. lamblia isolates were characterized by PCR-RFLP and qPCR using four loci genes (bg, gdh, tpi and orfC4). Of the 65 positive samples, 41 (63.1%) were successfully amplified by nested-PCR of bg and gdh genes. Among them, 16 were typed as sub-assemblage AII, 7 as BIII, 4 as BIV and 8 as a mixture of BIII and BIV. After the analysis by qPCR assay, a total of 55 (84.6%) samples were amplified using at least one locus: bg gene was amplified in 38 (58.5%) samples, gdh in 41 (63.1%), tpi in 39 (60%), and orfC4 in 39 (60%). Multilocus genotyping results showed that 29 (52.7%) samples belonged to Assemblage A and 26 (47.3%) samples belonged to Assemblage B. In 2011 and 2012, 20 (74.1%) samples belonged to Assemblage A and 7 (25.9%) belonged to Assemblage B. In subsequent years (2013–2015) there was a predominance of Assemblage B, 19 (67.9%) versus 9 (32.1%) Assemblage A.ConclusionsThis is the first time that Assemblage B of G. lamblia was reported in human clinical samples from Rio de Janeiro (Brazil) and is the first report about genetic characterization using four genes. The qPCR assemblage-specific showed no mixed infections by Assemblages A and B. A switch in genetic profile over the years was observed, firstly predominance of Assemblage A and lastly of Assemblage B.

Frequency and Molecular Detection of Giardia intestinalis in Children Attending Pediatrics of Punjab, Pakistan

“…The tpi gene PCR found 38 samples (55.07%) positive as assemblage B of G. intestinalis followed by assemblage A (28.98%), while the mix infection type (A + B) was detected in 11 samples making (15.94%). Similar trend of results was observed previously showing 64% assemblage B and 36% assemblage A in 2005 (20), 16% assemblage B and 10% assemblage A in 2013 (31), 67.9% assemblage B and 32.1% as assemblage A in 2016 (19) and 50.8% as type B followed by 27% as type A and 22.2% as mix types in 2017 (17). In contrast, a higher prevalence of assemblage A (54.8%) and (80%) was detected in 2011 and 2014, respectively (26,28).…”

“…Amplification of (SSU-rRNA) and (tpi) Genes for Detection of G. intestinalis: The extracted DNA was subjected to SSU-rRNA polymerase chain reaction using specific primers RH11 (5'-CATCCGGTCGATCCTGCC-3') and RH4 (5'-GTCGAACCCTGATTCTCCGCCAGG-3') to amplify a 292 bp product as described previously with slight modifications (19). The thermal cycler profiling was adjusted to 95°C for 05 min/1 cycle, 95°C for 30 sec/35 cycles, 58°C for 30 sec/35 cycles, 72°C for 45 sec/35 cycles and final extension at 72°C for 07 min/01 cycle using (Optimus 96G, Gradient Thermal Cycler, UK).…”

Recirculation of Giardia lamblia Assemblage A After Metronidazole Treatment in an Area With Assemblages A, B, and E Sympatric Circulation

“…The results here show that the circulation of these assemblages is still current, with assemblage A being amplified throughout the environment by pets (Volotão et al, 2007;Fantinatti et al, 2018). However, the identification of assemblage B circulating in infected children had not been verified, although the first identification of assemblage B in Rio de Janeiro was reported in the same period (Faria et al, 2016). Further studies of environmental samples could help to understand the predominance of assemblage A.…”

“…The frequency of assemblage A was higher in comparison to B or E. The few reports addressing the Giardia assemblages in Brazil point to regional differences in the prevalence of the predominant circulating assemblage (Coelho et al, 2017). In Rio de Janeiro, the assemblage A has been most frequently identified in humans (Volotão et al, 2007;Fantinatti et al, 2016), although assemblage B (Faria et al, 2016) and assemblage E (Fantinatti et al, 2016) have already been reported. The present results are consistent and reinforce the reported epidemiological profile of the Giardia assemblages in our region.…”

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

“…However, in a study conducted in the UK the distribution of the assemblages A and B were different in relation to age group; equal distribution in children, assemblage B more common in young adults and assemblage A more common in adults over 50 [40]. Previous studies conducted in Rio de Janeiro, Brazil, found only assemblage A isolates, with the first assemblage B reported in 2016 [48]. All the samples from the present study originated from adults, and were predominantly identified as assemblage A.…”