Description, Causes and Risk Factors:
A saprophytic fungus which causes abortion in cattle, eumycotic mycetoma (pseudoallescheriosis) in dogs and maduromycosis in humans. Previously called Allescheria Disseminated infection by Petriellidium (Allescheria) boydii occurred in an immunosuppressed renal allograft recipient. P. boydii, also known as Allescheria boydii, is an opportunistic fungus with the anamorph name of Scedosporium apiospermum. Present in soil, decaying vegetation, and stagnant or polluted water throughout the world, it is responsible for skin and systemic infections. Cutaneous involvement by direct inoculation consists of mycetoma, which is one of the main causes of Madura foot. Pseudallescheriasis, the systemic manifestation, is contracted through inhalation; near-drowning accident; or direct implantation from trauma, surgery, or other iatrogenic causes. It targets lung, bone, central nervous system, sinuses, eyes, heart, soft tissues, and skin. The localized form of pseudallescheriasis exhibits subacute or chronic courses in previously healthy patients. Disseminated and invasive pseudallescheriasis is encountered in patients who are debilitated and immunocompromised as a result of AIDS, immunosuppressive therapy, hematologic malignancy, diabetes, or transplantation. Lung infection mimics aspergillosis, with fungus balls in preexisting cavities and abscesses with central cavitation. Necrotizing pneumonitis is common in immunocompromised patients. Central nervous system manifestations, either by direct or hematogenous extension, include cerebral abscesses, meningitis, cerebritis, ventriculitis, and intracranial vascular involvement with imaging features similar to those of aspergillosis. Ocular infection encompasses keratitis, endophthalmitis, panophthalmitis, and, as seen in our patient, optic neuropathy.
The fungus usually enters the body by penetrating injury and causes infection in cutaneous and subcutaneous tissue of the foot. Extracutaneous sites of Disseminated petriellidosis are rare. Reserchers have found 16 reported cases of pulmonary infection with mostly occurred in farmers with underlying structural lung disease and usually in the non-invasive form of an opportunistic intracavitary mycetoma. Although rarely, this organism has been implicated in sinusitis, endophthalmitis, joint infection, parotitis, prostatitis, pachymeningitis, and brain abscess.
Disseminated petriellidosis is extremely rare. To our knowledge, only three cases have been reported. The first case was reported by Rosen in 1965 from Canada in a patient with subacute glomerulonephritis and treated with corticosteroid and azathioprine. Brain and thyroid abscess caused by the P. boydii were found at necropsy. Forno and Billingham subsequently described the second case of probable airborne pulmonary infection with systemic dissemination to the brain and thyroid in a case of steroid-treated systemic lupus erythematosus. The third similar case of Disseminated petriellidosis was reported by Walker in a renal allograft recipient taking methylprednisolone and azathioprine. Interestingly, brain and thyroid have been involved in all three reported disseminated cases as well as in the present case. All four had received systemic antibiotic therapy and immunosuppressive drugs before the development of the P. boydii infection. Almost all seriously invasive petriellidioses have occured in compromized hosts or in patients with predisposing underlying conditions.
Symptoms of Disseminated petriellidosis:
Symptoms may include:
Diagnosis Disseminated petriellidosis:
- Chest pain.
- Shortness of breath.
- Facial pain.
- Night sweat.
Soluble antigens in culture filtrates of three strains of Petriellidium boydii and three strains of Monosporium apiospermum were examined by researchers. Antigens were separated from concentrated crude filtrates by anion-exchange chromatography. A single major peak (Antigen 1), constituting a significant proportion of the total recoverable carbohydrate, was the only product isolated from each of four chromatographed filtrates. Depending on the fungus strain, Antigen 1 consisted of 90--96% carbohydrate, 3-4% protein, and 2-4% nucleic acid. Antigen 1 was found to consist of a population of molecules with a heterogeneous molecular size when assayed by gel filtration chromatography; however, isolated fractions of Antigen 1 proved to be immunologically identical when examined by Ouchterlony immunodiffusion. In addition, Antigen 1 from each strain was immunologically identical to similar preparations of Antigen 1 from the other five fungus strains. Chromatography of culture filtrates from two strains of M. apiospermum revealed a second peak (Antigen 2), which was found to consist of 70% carbohydrate, 16% protein, and 4% nucleic acid. Although Antigen 2 contained four times as much protein as Antigen 1, the two preparations were immunologically identical by immunodiffusion tests. Ion-exchange chromatography proved to be a useful procedure for isolating antigens of P. boydii and M. apiospermum from culture filtrates.
The fungus has been shown to be resistant in vitro to currently available antifungal agents. Resistance to amphotericin and 5-fluorocytosine is demonstrated in our studies. There are few reports of successful chemotherapy of any manifestation of this infection, and no such reports of visceral disease. Researchers demonstrated in vitro sensitivity of isolates in cases and in others to miconazole, a new antimicrobial agent; this drug may be indicated for treatment of disease due to P. boydii.
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