Peritonitis due to Prototheca wickerhamii in a patient undergoing chronic ambulatory peritoneal dialysis

New Approaches for risk assessment and management of bovine protothecosis

Protothecosis is a potential zoonosis related to bovine mastitis. In several countries, a higher incidence of protothecal bovine mastitis that is being recorded and the resistance of Prototheca species to various factors (chlorine, high temperatures, antimicrobial and antiseptic treatments, pH variations), make it difficult to control its spread among farms. The authors aim to describe the infection caused by microalgae, focusing on the problems within cattle farms and proposing new approaches to farm management, based on Regulation (EU) No 2016/429 on transmissible animal diseases. This new flexible approach, based on risk analysis, is a further tool in protecting against Prototheca species. The list of transmissible animal diseases under Regulation (EU) No 2016/429 includes those caused by microorganisms resistant to antimicrobials, which can have important implications for human and animal health, feed and food safety. This approach would involve a series of changes to the rules used for Official Controls (Regulation (EU) No 2017/625) moving from the concept of the food chain to that of the agri-food chain.

Human Disseminated Protothecosis: The Skin is the “Window”?

Human disseminated protothecosis is a rare infection caused by members of the genus Prototheca, an achlorophyllic algae always associated with debilitated hosts. The presence of non-budding cells and large, spherical cells (sporangia) with endosporulation (morula) in histology is proof of Prototheca infection. Regrettably, due to the lack of specificity of clinical features and low awareness among clinicians, protothecosis is always underestimated and misdiagnosed. The available data on a species-specific analysis of this infection are limited. In this review, we summarize the etiological, epidemiological, and clinical aspects of disseminated protothecosis. The potential pathogenicity and clinical differences between P. zopfii and P. wickerhamii were observed. Additionally, the skin not only became the main invasion site but also the most involved organ by the pathogen. With the increasing numbers of immunocompromised individuals throughout the world, the incidence of disseminated infection caused by Prototheca is bound to increase, and disseminated protothecosis that accompanies skin symptoms should be taken into account by clinicians.

Prototheca wickerhamii breast implant infection after reconstructive surgery: a new level of complexity

We report the first published case of Prototheca wickerhamii breast implant infection. This occurred after mastectomy, chemotherapy, radiotherapy, breast reconstruction, implant revisions and breast seroma aspirations and was preceded by polymicrobial infection. Definitive treatment required implant removal and intravenous liposomal amphotericin B. The management of breast prosthesis infections is discussed.

Prototheca wickerhamii algaemia presenting as cholestatic hepatitis in a patient with systemic lupus erythematosus: A case report and literature review

Human protothecal infection is uncommon and could be localized or systemic disease. Disseminated Prototheca algaemia tends to occur in immunocompromised patients (solid organ transplants, hematological malignancies) with high mortality. Diagnosis could be missed or delayed due to unusual clinical presentation and/or under-recognition of characteristic microscopic features of Prototheca species. Combined approach that includes removal of source of infection and intravenous amphotericin B provides the best chance of cure.

Human protothecosis

Human protothecosis is a rare infection caused by members of the genus Prototheca. Prototheca species are generally considered to be achlorophyllic algae and are ubiquitous in nature. The occurrence of protothecosis can be local or disseminated and acute or chronic, with the latter being more common. Diseases have been classified as (i) cutaneous lesions, (ii) olecranon bursitis, or (iii) disseminated or systemic manifestations. Infections can occur in both immunocompetent and immunosuppressed patients, although more severe and disseminated infections tend to occur in immunocompromised individuals. Prototheca wickerhamii and Prototheca zopfii have been associated with human disease. Usually, treatment involves medical and surgical approaches; treatment failure is not uncommon. Antifungals such as ketoconazole, itraconazole, fluconazole, and amphotericin B are the most commonly used drugs to date. Among them, amphotericin B displays the best activity against Prototheca spp. Diagnosis is largely made upon detection of characteristic structures observed on histopathologic examination of tissue.

Protothecosis

Intravenous amphotericin B remains the most effective drug for eradicating Prototheca infections. It should be used as a first-line agent in cases of disseminated disease and in patients with severe underlying illness or with immunosuppression or immunocompromise. Azole antifungals and surgery should be reserved for patients with more localized disease. Itraconazole appears to be the most effective agent of this drug class, and it should be administered at 200 mg/day for 2 months. Surgical excision should be considered as a first-line therapy in patients who present with olecranon bursal infections.

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.

Evaluation of the susceptibility of Prototheca zopfii to milk pasteurization

Protothecosis has been reported in humans (gastroenteritis, bursitis, etc.) and in many other animal species. Bovine mastitis represents the main form of occurrence of protothecosis in cattle. Milk as well as dairy products, when contaminated with Prototheca spp., represent a potential means of transmission of this zoonosis. The purpose of this study was to evaluate the susceptibility of forty Prototheca zopfii strains isolated from milk from intramammary infections in dairy cows and also from bulk milk tanks of dairy farms, to the different ratios of temperature/time employed in the thermal treatment of milk: 72-75 degrees C/15 seconds, 72-75 degrees C/20 seconds and 62-65 degrees C/30 minutes. The samples were subjected to these different temperature/time ratios. The evaluation of the thermal susceptibility of the P. zopfii strains showed that 34 strains were resistant in at least one of the tests. The results point out the need to consider the importance of mastitis caused by Prototheca spp. as representing a public health risk.

Algaemia due to Prototheca wickerhamii in a patient with myasthenia gravis

Prototheca wickerhamii is a rare cause of systemic infection in humans. While some cases occur in previously healthy individuals, others are associated with a variety of preexisting diseases. Here we present, for the first time, a case of P. wickerhamii algaemia in a patient with myasthenia gravis. The patient was successfully treated with amphotericin B.

Chronic Prototheca meningitis

A case of chronic meningitis caused by the achloric alga Prototheca wickerhamii is described, which has persisted for more than 6 years despite treatment with various antifungal agents. For the last year no treatment has been given, but the patient has no complaints.

New and emerging yeast pathogens

The most common yeast species that act as agents of human disease are Candida albicans, Candida tropicalis, Candida glabrata, Candida parapsilosis, and Cryptococcus neoformans. The incidence of infections by other yeasts has increased during the past decade. The most evident emerging pathogens are Malassezia furfur, Trichosporon beigelii, Rhodotorula species, Hansenula anomala, Candida lusitaniae, and Candida krusei. Organisms once considered environmental contaminants or only industrially important, such as Candida utilis and Candida lipolytica, have now been implicated as agents of fungemia, onychomycosis, and systemic disease. The unusual yeasts primarily infect immunocompromised patients, newborns, and the elderly. The role of central venous catheter removal and antifungal therapy in patient management is controversial. The antibiograms of the unusual yeasts range from resistant to the most recent azoles and amphotericin B to highly susceptible to all antifungal agents. Current routine methods for yeast identification may be insufficient to identify the unusual yeasts within 2 days after isolation. The recognition of unusual yeasts as agents of sometimes life-threatening infection and their unpredictable antifungal susceptibilities increase the burden on the clinical mycology laboratory to pursue complete species identification and MIC determinations. Given the current and evolving medical practices for management of seriously ill patients, further evaluations of the clinically important data about these yeasts are needed.

Cutaneous manifestations of Prototheca infections

The genus Prototheca comprises several species, the most prevalent of which is Prototheca wickerhamii. These achlorophyllic algae are found in the slime flux of trees and in freshwater environs. Cutaneous infection with these microbes was first reported 30 years ago. Subsequent case reports have described other manifestations including systemic disease. Asymptomatic and stationary cutaneous plaques may be seen in otherwise healthy patients. Susceptibility to infection is ill defined but may involve an inability of neutrophils to effectively eradicate phagocytosed organisms. Characteristic morula are seen histologically. Antifungal medications are the most effective therapy.

New and unusual infections in neutropenic patients

Infections in immunocompromised patients with cancer are common and the primary risk factor is neutropenia, usually induced by chemotherapeutic agents. The spectrum of bacterial infection is shifting from gram-negative to gram-positive. The array of fungal infections in cancer patients is expanding to include organisms previously unknown as invasive human pathogens. New species are being defined to explain extant pathologies, and free living algae are now emerging as pathogens in immunocompromised patients. Physicians must remain alert to these emerging pathogens and to the need to evaluate optimal treatments for the usual and unusual infections in neutropenic and other compromised patients with cancer and allied diseases.