Management of rare fungal infections

How a discerning cytological examination can aid in the diagnosis of infectious diseases: case reports

Infections caused by uncommon and resistant pathogens in unusual sites have been increasingly reported in medical literature. We describe four cases of rare cytological findings and clinical impact for patients. In the first case, Aspergillus sp and Pneumocystis jirovecii were observed in the bronchoalveolar lavage of a patient with severe systemic lupus. In the second and third cases, we describe the presence of Trichomonas sp and Strongyloides sp larvae in samples of pleural and peritoneal fluid, respectively. The fourth report is about a patient with a wrist subcutaneous nodule whose synovial aspiration and cytology revealed the presence of brown septate hyphae. The early identification of the infectious agent in the cytological examination was essential for the introduction and/or re-adaptation of therapy in the four cases described. Patients in this report were immunocompromised with severe comorbidities, conditions often associated with unfavorable clinical outcomes.

Basidiobolus haptosporus-like fungus as a causal agent of gastrointestinal basidiobolomycosis

Basidiobolus species were isolated from colonic biopsy samples of patients with gastrointestinal basidiobolomycosis (GIB) in southern Saudi Arabia. Isolated fungi were initially identified using classical mycological tools and confirmed by sequence analysis of the large subunit ribosomal RNA gene. Phenotypic tests revealed zygomycete-like fungi which conform to those of Basidiobolus species. Five sequenced strains formed a monophyletic clade in the 28S ribosomal RNA gene phylogenetic tree. They shared 99.97% similarity with B. haptosporus and 99.97% with B. haptosporus var. minor, and relatively lower similarity with B. ranarum (99.925%). The study suggests a new and a serious causal agent of GIB related to Basidiobolus haptosporus. These isolates are not related to B. ranarum, which is commonly linked to this disease.

Fusarium pathogenesis investigated using Galleria mellonella as a heterologous host

Members of the fungal genus Fusarium are capable of manifesting in a multitude of clinical infections, most commonly in immunocompromised patients. In order to better understand the interaction between the fungus and host, we have developed the larvae of the greater wax moth, Galleria mellonella, as a heterologous host for fusaria. When conidia are injected into the haemocoel of this Lepidopteran system, both clinical and environmental isolates of the fungus are able to kill the larvae at 37 °C, although killing occurs more rapidly when incubated at 30 °C. This killing was dependent on several other factors besides temperature, including the Fusarium strain, the number of conidia injected, and the conidia morphology, where macroconidia are more virulent than their microconidia counterpart. There was a correlation in the killing rate of Fusarium spp. when evaluated in G. mellonella and a murine model. In vivo studies indicated G. mellonella haemocytes were capable of initially phagocytosing both conidial morphologies. The G. mellonella system was also used to evaluate antifungal agents, and amphotericin B was able to confer a significant increase in survival to Fusarium-infected larvae. The G. mellonella-Fusarium pathogenicity system revealed that virulence of Fusarium spp. is similar, regardless of the origin of the isolate, and that mammalian endothermy is a major deterrent for Fusarium infection and therefore provides a suitable alternative to mammalian models to investigate the interaction between the host and this increasingly important fungal pathogen.

Subcutaneous phaeohyphomycosis on the scrotum caused by Exophiala jeanselmei: case report

Subcutaneous phaeohyphomycosis is a disease caused by dematiaceous fungi that develops mainly in immunocompromised patients. Lesions are generally located on the lower limbs. The present report describes a case of phaeohyphomycosis in an immunocompetent patient in whom a subcutaneous abscess was located in an unusual site, on the left hemiscrotum. The abscess was treated successfully with oral fluconazole associated with surgical excision.

Fusarium infection in lung transplant patients: report of 6 cases and review of the literature

Fusarium is a fungal pathogen of immunosuppressed lung transplant patients associated with a high mortality in those with severe and persistent neutropenia. The principle portal of entry for Fusarium species is the airways, and lung involvement almost always occurs among lung transplant patients with disseminated infection. In these patients, the immunoprotective mechanisms of the transplanted lungs are impaired, and they are, therefore, more vulnerable to Fusarium infection. As a result, fusariosis occurs in up to 32% of lung transplant patients. We studied fusariosis in 6 patients following lung transplantation who were treated at Massachusetts General Hospital during an 8-year period and reviewed 3 published cases in the literature. Cases were identified by the microbiology laboratory and through discharge summaries. Patients presented with dyspnea, fever, nonproductive cough, hemoptysis, and headache. Blood tests showed elevated white blood cell counts with granulocytosis and elevated inflammatory markers. Cultures of Fusarium were isolated from bronchoalveolar lavage, blood, and sputum specimens.Treatments included amphotericin B, liposomal amphotericin B, caspofungin, voriconazole, and posaconazole, either alone or in combination. Lung involvement occurred in all patients with disseminated disease and it was associated with a poor outcome. The mortality rate in this group of patients was high (67%), and of those who survived, 1 patient was treated with a combination of amphotericin B and voriconazole, 1 patient with amphotericin B, and 1 patient with posaconazole. Recommended empirical treatment includes voriconazole, amphotericin B or liposomal amphotericin B first-line, and posaconazole for refractory disease. High-dose amphotericin B is recommended for treatment of most cases of fusariosis. The echinocandins (for example, caspofungin, micafungin, anidulafungin) are generally avoided because Fusarium species have intrinsic resistance to them. Treatment should ideally be based on the Fusarium isolate, susceptibility testing, and host-specific factors. Prognosis of fusariosis in the immunocompromised is directly related to a patient's immune status. Prevention of Fusarium infection is recommended with aerosolized amphotericin B deoxycholate, which also has activity against other important fungi.

How immunocompromised are short bowel patients receiving home parenteral nutrition? Apropos a case of disseminated Fusarium oxysporum sepsis

BACKGROUND

Catheter-related sepsis is the most frequent complication in patients receiving home parenteral nutrition (HPN) for short bowel syndrome (SBS). A low-grade systemic inflammatory state and an altered mucosal immune response, as well as diminished intestinal barrier function have been characterized in these patients. The possibility of systemic immunocompromise has only recently been suggested.

CASE DESCRIPTION

A 45-year-old female with traumatic SBS was admitted for possible catheter-related sepsis. She was asplenic and had insulin-dependent diabetes mellitus as a result of a pancreatic resection. A large skin ulceration was present on her left calf, which appeared unusual for a disseminated bacterial infection. Chest x-ray and computed tomography scan revealed multiple subpleural pulmonary infiltrates consistent with bacterial or fungal dissemination. Blood cultures from the port system and from the peripheral blood grew Staphylococcus haemolyticus and Fusarium oxysporum. The port system was removed, and flucloxacillin and voriconazole were given for 33 and 35 days, respectively. Clinical signs of disseminated sepsis resolved slowly. Bone marrow biopsy ruled out primary hematologic disease.

CONCLUSIONS

(1) Catheter-related sepsis in patients on HPN is usually caused by Gram-positive or Gram-negative bacteria or by Candida species. Identification of molds in blood cultures strongly suggests Fusarium species, which should be treated appropriately with voriconazole or amphotericin B. (2) HPN and SBS aggravated by asplenism and diabetes mellitus can cause severe immunocompromise. (3) Fusaria have a strong tendency to persist or reappear after bone marrow transplantation, which is therefore relatively contraindicated in these patients.

Gastrointestinal basidiobolomycosis: an unusual fungal infection mimicking colon cancer

CONTEXT

-Basidiobolomycosis is a rare disease caused by the fungus Basidiobolus ranarum, an environmental saprophyte found worldwide. Patients with B ranarum infection may present with subcutaneous, gastrointestinal, or systemic lesions. Gastrointestinal basidiobolomycosis poses diagnostic difficulties, as its clinical presentation is nonspecific, with no identifiable risk factors.

OBJECTIVE

-To discuss and compare the clinical features and histopathologic findings and other ancillary techniques that could be helpful in identifying gastrointestinal basidiobolomycosis.

DESIGN

-We report 3 cases of gastrointestinal basidiobolomycosis and describe the clinical and morphologic findings while emphasizing the importance of identifying this unusual entity on endoscopic biopsies, thus avoiding unnecessary major surgeries. Fungal cultures were also performed, which are of diagnostic significance. Our first patient was lost to follow-up; however, patients 2 and 3 were followed up for 4 and 2 years, respectively.

RESULTS

-In all 3 cases, patients presented with a clinical profile suggestive of malignancy. None of the patients gave any specific history. There was widespread abdominal disease with peritoneal involvement and colonic masses. Colonoscopic biopsy specimens showed nonspecific inflammation in 1 case; however, they showed only granulomatous inflammation in a second case and granulomas associated with fungal hyphae in a third. Typical morphology included hyphae, irregularly branched, thin-walled, occasionally septated and surrounded by a thick eosinophilic cuff (Splendore-Hoeppli phenomenon).

CONCLUSION

-Gastrointestinal basidiobolomycosis can be detected on small endoscopic biopsy. The unequivocal diagnosis requires microbiologic cultivation of the fungus obtained from tissues. The prognosis for this disease is usually favorable as seen in 3 of our cases; however, cases with fatal outcome are on record.

JAAD Grand Rounds quiz. Asymptomatic necrotic ulcer on leg

LEARNING OBJECTIVES

At the conclusion of this learning activity, physician participants should be able to assess their own diagnostic and patient management skills and use the results of this exercise to help determine personal learning needs that can be addressed through subsequent CME involvement. Instructions for claiming CME credit appear in the front advertising section. See last page of Contents for page number. Instructions: In answering each question, refer to the specific directions provided. Because it is often necessary to provide information occurring later in a series that give away answers to earlier questions, please answer the questions in each series in sequence.

Fungal Infections

The incidence of invasive fungal infections has increased dramatically over the past two decades, mostly due to an increase in the number of immunocompromised patients.1–4 Patients who undergo chemotherapy for a variety of diseases, patients with organ transplants, and patients with the acquired immune deficiency syndrome have contributed most to the increase in fungal infections.5 The actual incidence of invasive fungal infections in transplant patients ranges from 15% to 25% in bone marrow transplant recipients to 5% to 42% in solid organ transplant recipients.6,7 The most frequently encountered are Aspergillus species, followed by Cryptococcus and Candida species. Fungal infections are also associated with a higher mortality than either bacterial or viral infections in these patient populations. This is because of the limited number of available therapies, dose-limiting toxicities of the antifungal drugs, fewer symptoms due to lack of inflammatory response, and the lack of sensitive tests to aid in the diagnosis of invasive fungal infections.1 A study of patients with fungal infections admitted to a university-affiliated hospital indicated that community-acquired infections are becoming a serious problem; 67% of the 140 patients had community-acquired fungal pneumonia.8

Imaging of isolated cerebral mucormycosis. A report of three cases

Mucormycosis is a rare infection in immunosupressed patients caused by fungi from the family Mucoraceae. Three types of disease spread have been described: rhinocerebral, systemic and isolated. Isolated spread is the most uncommon form, usually resulting in death. It has been described in diabetics, immunosupressed patients and intravenous drug abusers. Neuroimaging can aid the diagnosis of this entity, but biopsy remains the only reliable method. Imaging findings of Mucormycosis include abscesses and hemorrhagic or ischemic infarcts, usually in the basal ganglia and frontal lobes. Single or multiple lesions have been described as well as meningoencephalitis. Understanding these findings can help to detect the infection in an early stage. We describe three cases of isolated cerebral mucormycosis; all of them were intravenous drug abusers with one patient also being HIV positive.

Implantable cardioverter-defibrillator infection due to Scedosporium apiospermum

We report a case of implantable cardioverter-defibrillator infection due to Scedosporium apiospermum. This infection persisted despite systemic antifungal treatment with voriconazole and was controlled after removal of the foreign device and replacement of the involved tricuspid valve. This case underscores the importance of a combined surgical and medical approach for this complicated infection. Scedosporium species should be considered in the differential diagnosis of cardiac or intravascular device-related infections.

Successful treatment of Ochroconis gallopavum infection in an immunocompetent host

Ochroconis gallopavum, a dematiaceous fungus, is a rare cause disease in immunocompromised patients and epidemic encephalitis in poultry. We report the first case of active O. gallopavum pulmonary infection in an immunocompetent host with rapid and complete response to oral antifungal therapy.

Histological and ultrastructural features of gastrointestinal basidiobolomycosis

Basidiobolus ranarum is a fungus found in the dung of amphibians, reptiles, and insectivorous bats. Its structural elements include both hyphae and zygospores. Patients with B. ranarum infection may present with subcutaneous, gastrointestinal, or systemic lesions. Here we report a case of gastrointesinal badidiomycosis in a 13-year-old male child who presented with acute abdomen. Exploration revealed a mass in the ascending colon. On histology, transmural granulomatous inflammation composed of abundant eosinophils, lymphocytes, histiocytes and giant cells was seen. Histochemical stains revealed broad, non-septate, hyphae-like structures surrounded by an eosinophilic sheath. On an ultrastructural level, fungal hyphae, spores, and macrophage-laden crystalloids were observed. The diagnosis of gastrointestinal basidiobolomycosis was established and the patient received antifungal treatment. This paper reviews the relevant literature regarding basidiomycosis, and discusses its diverse clinicopathological features, as well as distinguishing it from other diseases.

Central nervous system infections in transplantation

Central nervous system (CNS) infections are a rare but serious complication of transplantation. An appropriate diagnostic workup should be streamlined with stratification of infection risk by length and degree of immune suppression, lesion localization, and timing. Polymerase chain reaction has high sensitivity and specificity for rapid identification of viral infections and should be used when available. Early diagnosis is imperative, and biopsy should be pursued if a diagnosis is not readily obtained with noninvasive testing. Treatment is pathogen specific. Combination antifungal therapy should be considered for cerebral aspergillosis. Zygomycetes and related invasive fungi require surgical resection and high-dose antifungal therapy. Viral meningoencephalitis therapy should be continued until resolution of clinical signs and symptoms, and viral clearance is verified with repeat cerebrospinal fluid analysis. Cytomegalovirus encephalitis requires ongoing maintenance therapy until clearance of viremia or antigenemia. Bacterial meningitis is uncommon in transplantation and should be treated with 21 days of antibiotics. CNS bacterial abscesses, including nocardiosis, should be surgically drained if feasible and treated until resolution of clinical and radiographic evidence of infection.

Emerging Fungal Diseases

The epidemiology of invasive fungal infection is evolving. Yeasts other than Candida albicans and molds other than Aspergillus fumigatus have emerged as significant causes of invasive mycoses in severely immunocompromised patients. Although, in some instances, these changes may be related to medical interventions, such as the use of antifungal agents in prophylaxis, in the majority of cases, they seem to be a consequence of changes in the host, such as more-severe immunosuppression or different types of immunosuppression impacting both risk periods and the infections that occur. These factors have altered the epidemiology of infection in organ transplant recipients, premature newborns, and critically ill patients. This review discusses the epidemiology of some fungal infections that have emerged in the past few years, with an emphasis on the potential factors associated with their emergence and on practical implications of these epidemiological changes.