Molecular diversity and frequency of the diarrheagenic enteric protozoan Giardia duodenalis and Cryptosporidium spp. in a hospital setting in Northern Spain

Abstract

BackgroundHuman giardiosis and cryptosporidiosis are caused by the enteric protozoan parasites Giardia duodenalis and Cryptosporidium spp. Both pathogens are major contributors to the global burden of diarrhoeal disease, affecting primarily children and immunodebilitated individuals in resource-poor settings. Giardiosis and cryptosporidiosis also represent an important, often underestimate, public health threat in developed countries. In Spain only limited information is currently available on the epidemiology of these infections. Molecular data on the diversity, frequency, geographical distribution, and seasonality of G. duodenalis assemblages/sub-assemblages and Cryptosporidium species/sub-genotypes are particularly scarce.MethodsA longitudinal molecular epidemiological survey was conducted between July 2015 to September 2016 in patients referred to or attended at the Hospital San Pedro (La Rioja, Northern Spain) that tested positive for G. duodenalis (N = 106) or Cryptosporidium spp. (N = 103) by direct microscopy and/or a rapid lateral flow immunochromatographic assay. G. duodenalis infections were subsequently confirmed by real-time PCR and positive isolates assessed by multi-locus sequence genotyping of the glutamate dehydrogenase and β-giardin genes of the parasite. Cryptosporidium species and sub-genotypes were investigated at the 60 kDa glycoprotein or the small subunit ribosomal RNA genes of the parasite. Sociodemographic and clinical parameters of infected patients were also gathered and analysed.Principal findingsOut of 90 G. duodenalis-positive isolates by real-time PCR a total of 16 isolates were successfully typed. AII (44%, 7/16) was the most prevalent sub-assemblage found, followed by BIV (31%, 5/16) and BIII (19%, 3/16). A discordant genotype result AII/AIII was identified in an additional (6%, 1/16) isolate. No mixed infections A+B were detected. Similarly, a total of 81 Cryptosporidium spp. isolates were successfully typed, revealing the presence of C. hominis (81%, 66/81) and C. parvum (19%, 15/81). Obtained GP60 sequences were assigned to sub-type families Ib (73%, 59/81) within C. hominis, and IIa (7%, 6/81) and IId (2%, 2/81) within C. parvum. A marked inter-annual variation in Cryptosporidium cases was observed.ConclusionsHuman giardiasis and cryptosporidiosis are commonly identified in patients seeking medical care in Northern Spain and represent a more important health concern than initially thought. Assemblage A within G. duodenalis and sub-genotype IbA10G2 within C. hominis were the genetic variants of these parasite species more frequently found circulating in the population under study. Molecular data presented here seem to suggest that G. duodenalis and Cryptosporidium infections arise through anthroponotic rather than zoonotic transmission in this Spanish region.

Giardiasis in children: molecular genotyping, growth and calprotectin levels

“…Similar results were obtained 15 . However, the results did not reveal mixed groups A and B 16 . High genetic variability and the frequency of double peaks make sub-genotyping problematic.…”

The red fox ( Vulpes vulpes ) as a potential natural reservoir of human cryptosporidiosis by Cryptosporidium hominis in Northwest Spain

“…Even more intriguing was the fact that three out of the four C. hominis sequences generated at the ssu rRNA locus corresponded to genetic variants of the parasite not described previously, whereas the fourth one was identified as a genotype commonly seen in Spanish clinical patients (e.g. GenBank accession number KY499055) (Azcona‐Gutiérrez et al., 2017; de Lucio et al., 2016). Such variety of distinct, novel sequences may be indicative of true C. hominis infections rather than accidental carriage (spurious infection) of ingested oocysts of the parasite.…”

Multilocus genotyping of Giardia duodenalis in Southwestern Iran. A community survey

“…Analysis of the sequences obtained at the gdh locus allowed the identification of sub-assemblage AII and discordant genotype BIII/BIV results in 5 (62.5%) and 3 (37.5%) isolates, respectively. Azcona-Gutierrez et al (2017) genotyped 90 human isolates of G. duodenalis at the gdh and bg genes, reporting discordant genotyping results in one (6%) isolate [54]. In another study conducted by Skhal et al (2017) discordant genotype results BIII/BIV were reported in four (10%) isolates [55].…”