Molecular characterization ofProtothecain 11 symptomatic dogs

Abstract

Protothecosis is an uncommon disease caused by algae of the genus Prototheca. In dogs, the infection is usually first localized to the colon but has the propensity to later disseminate hematogenously to many other organs, with marked tropism for the eyes and central nervous system. Diagnosis is established by culture and/or evidence of Prototheca organisms in cytologic or histologic preparations. Species characterization, however, requires molecular investigations. Our laboratory set up a real-time PCR targeting portion D1/D2 of the 28S rRNA for identification of Prototheca species from both positive cultures (of rectal swabs and urine) and formalin-fixed, paraffin-embedded tissue. Prototheca bovis, P. ciferrii, and P. wickerhamii were characterized in 11 dogs with systemic or cutaneous protothecosis. Prototheca identifications were phylogenetically consistent with the new taxonomy proposed for this genus based on the mitochondrial cytochrome b gene. As a pilot study, we screened feces and rectal scrapes from 200 asymptomatic dogs, using 2 cohorts of stray and owned animals, to determine the prevalence of intestinal carriage of Prototheca spp. The Prototheca-negative results from both cohorts of healthy dogs suggest that predisposing factors related to the host probably contribute more to the acquisition of clinical disease than exposure to contaminated environments.

Genome Sequences of Two Strains of Prototheca wickerhamii Provide Insight Into the Protothecosis Evolution

“…The investigation of molecular epidemiology of P. wickerhamii is still limited. There were only a few studies including P. wickerhamii drug susceptibility tests and unrooted phylogenetic trees which were based on nuclear rDNA transcriptional units (Falcaro et al, 2021). In vitro, P. wickerhamii was generally susceptible to amphotericin and had variable susceptibility to triazoles (McMullan et al, 2016).…”

“…The analysis of the P. wickerhamii 28S rRNA sequences revealed higher heterogeneity than cytb mitochondrial DNA sequences. A partial cytochrome b (CYTB) gene sequences had been used for identification of P. wickerhamii previously (Falcaro et al, 2021). The nucleotide sequences were heterogeneously different in rDNA copies of P. wickerhamii ITS, which might be useful for the intraspecies genotypic classification (Hirose et al, 2013).…”

Canine eumycetoma caused by Madurella pseudomycetomatis

“…Ten micron-thick sections (n=4) were submitted for molecular characterization by using SYBR Green Real-Time PCR (rtPCR) as reported previously [ 6 ].…”

Spinal cord protothecosis causing paraparesis in a dog

“…Differences in sugar and alcohol assimilation or antimicrobial susceptibility are required for routine species differentiation, whereas rRNA sequencing is needed to differentiate P. zopfii biotypes. 4,6,10,16,17 P. zopfii genotype 2 is the isolate that causes disseminated protothecosis most commonly in dogs. 16 Based on a retrospective study, the natural course of canine protothecosis appears to start with granulomatous colitis, which then slowly progresses.…”

“…Differences in sugar and alcohol assimilation or antimicrobial susceptibility are required for routine species differentiation, whereas rRNA sequencing is needed to differentiate P. zopfii biotypes. 4,6,10,16,17…”