[Prototheca as parasites of skin].
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Adult↗
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Fissuricella gen. nov.: a new taxon for Prototheca filamenta.
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Bone Marrow↗
[Behavior of prototheca species in mammalian tissue].
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Animals↗
Prototheca, a cause of bovine mastitis.
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Animals↗
The reserve polysaccharides of Prototheca zopfli.
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Eukaryota↗
Urinary tract manifestations of protothecosis in dogs.
Records of 13 dogs with systemic infection with Prototheca sp. from 3 veterinary teaching hospitals were reviewed. Acute renal failure secondary to disseminated infection with Prototheca zopfii was diagnosed in 2 dogs. In 1 dog, acute renal failure developed during administration of immunosuppressive drugs for treatment of anterior uveitis. During diagnostic evaluation of this dog, Prototheca sp. organisms were noted in urine sediment and renal biopsy specimens. In the 2nd dog, acute renal failure was diagnosed after treatment for bacterial cystitis. After diagnosis of protothecosis, organisms were successfully isolated by aerobic urine culture. Both dogs with acute renal failure did not respond to conventional medical therapy. In total, Prototheca sp. was noted in urine sediment in 4 of 8 dogs and successfully cultured from urine in 5 of 7 dogs. Four of 5 dogs had organisms noted in the kidneys on histopathologic examination. In all dogs, the species identified was P zopfii. Sensitivity testing of 3 isolates revealed wide differences in in vitro drug resistance. Examination and culture of urine is recommended as a practical method for diagnosis of systemic infection with Prototheca sp.
Acute Kidney Injury↗
Comparison of plastid 16S rRNA (rrn16) genes from Helicosporidium spp.: evidence supporting the reclassification of Helicosporidia as green algae (Chlorophyta).
The Helicosporidia are invertebrate pathogens that have recently been identified as non-photosynthetic green algae (Chlorophyta). In order to confirm the algal nature of the genus Helicosporidium, the presence of a retained chloroplast genome in Helicosporidia cells was investigated. Fragments homologous to plastid 16S rRNA (rrn16) genes were amplified successfully from cellular DNA extracted from two different Helicosporidium isolates. The fragment sequences are 1269 and 1266 bp long, are very AT-rich (60.7 %) and are similar to homologous genes sequenced from non-photosynthetic green algae. Maximum-parsimony, maximum-likelihood and neighbour-joining methods were used to infer phylogenetic trees from an rrn16 sequence alignment. All trees depicted the Helicosporidia as sister taxa to the non-photosynthetic, pathogenic alga Prototheca zopfii. Moreover, the trees identified Helicosporidium spp. as members of a clade that included the heterotrophic species Prototheca spp. and the mesotrophic species Chlorella protothecoides. The clade is always strongly supported by bootstrap values, suggesting that all these organisms share a most recent common ancestor. Phylogenetic analyses inferred from plastid 16S rRNA genes confirmed that the Helicosporidia are non-photosynthetic green algae, close relatives of the genus Prototheca (Chlorophyta, Trebouxiophyceae). Such phylogenetic affinities suggest that Helicosporidium spp. are likely to possess Prototheca-like organelles and organelle genomes.
Chlorella↗
[Human protothecosis and environment].
Protothecosis are uncommon infections caused by Prototheca, considered to be achlorophylous algae. Nearly 80 human cases are reported in the literature since the first case described by Davies and Wakelin in 1964 in Sierra Leone (11). The disease have been identified in Europe, Asia (Japan, Thailand, China), Oceania and in the United States with 40 cases, particularly in the Southeast. Clinically, three clinical manifestations can be observed: 1) cutaneous lesions: papules, plaques or eczematoid, papulo-nodular areas of the extremities, 2) olecranon bursitis which occurred in 25% of cases, 3) systemic protothecosis. An immunosuppressive factor local or general can be found in half of the cases and the first description of algal meningitis was reported in a patient with AIDS in association with Cryptococcus neoformans. Because the disease is clinically not suspected, the diagnosis is often provided by histology showing a dermic granuloma with endospores. The characteristic feature of protothecosis in tissues is the presence of specific mature sporangia of Prototheca wickerhamii with the pattern of morula. The organism was PAS, Grocott and mucicarmin positive. The ecology was studied by Clark (7), Pidoux (23), Pore (25) and Sudman (27). Prototheca are ubiquitous inhabitants of sewages and are found in slime flux and animal wastes contaminating different aquatic systems. The transmission generally occurred by traumatic inoculation. Prototheca are also found in the digestive system of man and animals without never invasion of the epithelium and mucosae in experimental models. The pathogenicity and virulence are moderate and they are considered as rare opportunistic agents.
Animals↗
First human case of possible protothecosis in Spain.
Prototheca wickerhamii was isolated from the stool of a two month-old infant with diarrhea resistant to treatment. This is the first description from Spain of algae of the genus Prototheca isolated from human clinical specimens. The possible pathogenicity of the Prototheca in this case is discussed.
Gastroenteritis↗
The non-photosynthetic, pathogenic green alga Helicosporidium sp. has retained a modified, functional plastid genome.
A fragment of the Helicosporidium sp. (Chlorophyta: Trebouxiophyceae) plastid genome has been sequenced. The genome architecture was compared to that of both a non-photosynthetic relative (Prototheca wickerhamii) and a photosynthetic relative (Chlorella vulgaris). Comparative genomic analysis indicated that Helicosporidium and Prototheca are closely related genera. The analyses also revealed that the Helicosporidium sp. plastid genome has been rearranged. In particular, two ribosomal protein-encoding genes (rpl19 and rps23) appeared to have been transposed, or lost from the Helicosporidium sp. plastid genome. RT-PCR reactions demonstrated that the retained plastid genes were transcribed, suggesting that, despite rearrangement(s), the Helicosporidium sp. plastid genome has remained functional. The modified plastid genome architecture is a novel apomorphy that indicates that the Helicosporidia are highly derived green algae, more so than Prototheca spp. As such, they represent a promising model to study organellar genome reorganizations in parasitic protists.
Algal Proteins↗
Protothecosis in patients with cancer: case series and literature review.
OBJECTIVE: To review our recent experience with protothecosis in patients with cancer at The University of Texas MD Anderson Cancer Center, and compare these cases with others reported in the literature. METHODS: We report on three patients with protothecosis and cancer who were seen at The University of Texas MD Anderson Cancer Center from January 1979 to May 2002, and reviewed all cases of protothecosis in patients with cancer reported in the literature since 1966. RESULTS: Overall, 13 cases of protothecosis complicating cancer were evaluated. The median age of the patients was 41 years (range, 7-73 years). Seven patients (54%) had an underlying hematologic malignancy, and one infection occurred after bone marrow transplantation. Neutropenia was uncommon in these patients (14%). Prototheca wickerhamii was the most common Prototheca species identified as the causative agent of infection. Skin infection was the most common presentation of protothecosis, occurring in five patients (38%), followed by disseminated disease in three patients (23%), algaemia in three patients (23%), pulmonary infection in one patient (8%), and olecranon bursitis in one patient (8%). Information on the use of antifungal therapy was available for ten patients. Seven of the ten patients received amphotericin B, while three received triazoles (fluconazole in two, itraconazole in one). Breakthrough protothecosis occurred during the administration of systemic antifungal therapy with itraconazole in one patient. All seven patients who received amphotericin B showed a response, as did one of the three patients given triazoles. Seven (58%) of the patients died during the study period, only one (17%) of protothecosis. CONCLUSIONS: Protothecosis is an uncommon infection in cancer patients, implying that Prototheca spp. have a low pathogenic potential in this population. Pulmonary involvement in particular is uncommon in these patients. Amphotericin B appears to be the most effective antifungal agent; the role of triazoles in treating protothecosis is uncertain, but they may be less effective.
Adult↗
Protothecosis in human medicine.
Prototheca spp. are ubiquitous achlorophyllous algae that produce disease in humans and animals. In the past years infections with Prototheca have obtained increasing importance in human medicine. The cases have been classified into three clinical forms: cutaneous and/or subcutaneous infection, synovitis of olecranon bursa or other fibrous tissue and systemic infection. Patients with a mild degree of immunosuppression may become colonized by Prototheca spp. with a subsequent worsening of their immune surveillance and spread of the disease. Among the numerous pharmacologic agents tried, amphotericin B is the most promising. Successful treatment of protothecosis involves radical excision of the involved structures.
Amphotericin B↗
Protothecal enteritis as a cause of protein-losing enteropathy in a bull.
Prototheca spp are achlorophyllic saprophytic algae found in wastewater, sewage, agricultural waste, and possibly elsewhere in the environment. Infections with these organisms have been reported in cattle, humans, and dogs; affected cattle commonly develop mastitis. A 5-year-old Brahman-cross bull was evaluated because of a history of diarrhea and weight loss. The history and physical examination and clinicopathologic findings were similar to those associated with granulomatous enteritis caused by Mycobacterium avium subsp paratuberculosis (Johne's disease), which is the most common protein-losing enteropathy of cattle. However, diagnostic tests for paratuberculosis yielded negative results. Biopsy specimens from the ileum, jejunum, and ileocecal lymph node were collected for histologic examination and preparation of tissue impression smears; Prototheca-like organisms were identified. Because of the poor prognosis associated with this infection and the lack of safe and economical therapeutic agents for cattle, the owner decided to euthanatize the bull. Infection with Prototheca organisms was confirmed postmortem. As this case illustrates, protothecosis may be a cause of granulomatous enteritis in cattle.
Animals↗
Differential microbiological diagnosis of protothecosis from non-human sources.
Primary isolation of Prototheca was accomplished on MacConkey's, sheep blood agar, and Sabouraud dextrose agar. Prototheca was differentiated from similar organisms by its ability to grow on MacConkey's agar, and by its colonial morphology. Further differentiation was based on staining procedures to reveal the characteristic microscopic morphology. In the process of identification of several isolates of Prototheca zophii obtained from animal sources, a simple guideline for isolation and identification of these organisms was developed.
Agar↗
Disseminated protothecosis with central nervous system involvement in a dog.
A 4-year-old mixed-breed spayed bitch was euthanatized after 2 1/2 months of progressive neurologic disease. Prototheca organisms were identified by histopathology, culture, and electron microscopy. Specific fluorescent antibody procedures revealed two species--Prototheca wickerhamii and Prototheca zopfii. Organisms and pyogranulomatous lesions were found in the brain, spinal cord, right eye, kidneys, and heart.
Animals↗
Complex patterns of plastid 16S rRNA gene evolution in nonphotosynthetic green algae.
This study provides a phylogenetic/comparative approach to deciphering the processes underlying the evolution of plastid rRNA genes in genomes under relaxed functional constraints. Nonphotosynthetic green algal taxa that belong to two distinct classes, Chlorophyceae (Polytoma) and Trebouxiophyceae (Prototheca), were investigated. Similar to the situation described previously for plastid 16S rRNA genes in nonphotosynthetic land plants, nucleotide substitution levels, extent of structural variations, and percentage AT values are increased in nonphotosynthetic green algae compared to their closest photosynthetic relatives. However, the mutational processes appear to be different in many respects. First, with the increase in AT content, more transversions are noted in Polytoma and holoparasite angiosperms, while more transitions characterize the evolution of the 16S rDNA sequences in Prototheca. Second, although structural variations do accumulate in both Polytoma and Prototheca (as well as holoparasitic plastid 16S rRNAs), insertions as large as 1.6 kb characterize the plastid 16S rRNA genes in the former, whereas significantly smaller indels (not exceeding 24 bp) seem to be more prevalent in the latter group. The differences in evolutionary rates and patterns within and between lineages might be due to mutations in replication/repair-related genes; slipped-strand mispairing is likely the mechanism responsible for the expansion of insertions in Polytoma plastid 16S rRNA genes.
Chlorophyta↗
Bovine protothecosis. A brief report of ten cases.
Prototheca zopfii was isolated repeatedly from milk samples from ten cows (of a herd of 192 dairy cows) with reduced milk yield and indurated mammary glands. The strain was moderately sensitive to streptomycin, polymyxin and gentamycin, but resistant or relatively resistant to other antibiotics and antimycotics commonly used in clinical practice. An attempt to treat the infection with Ethidium bromide, which was found effective in vitro, did not succeed. The number of Prototheca excreted decreased, but a complete cure was not obtained. In histological sections of the udder, Prototheca cells were demonstrated both intracellularly and interstitially.
Animals↗
Cutaneous protothecosis in a patient receiving immunosuppressive therapy.
A 30-year-old recipient of a renal transplant, who was receiving immunosuppressive therapy, developed cutaneous abscesses from which an organism of the genus Prototheca was cultured. The patient died of Klebsiella septicemia. At the time of death, pure cultures of Prototheca and Candida organisms were grown from separate skin lesions. Prototheca is a genus of achloric algae. Cultural, microscopical, and staining characteristics separate these organisms from the yeast and fungi. Cutaneous protothecosis was first described in 1964 by Davies et al in an otherwise healthy African rice farmer. Since that time, nine other cases have been reported. However, only a single case has been described in a patient receiving immunosuppressive drugs, a woman with carcinoma of the breast who was receiving chemotherapy with multiple agents.
Abscess↗