Histoplasma Capsulatum Var Research Articles

Answer to September 2013 Photo Quiz

Answer: Concurrent pulmonary infection with both Pneumocystis jirovecii and Histoplasma capsulatum var. capsulatum. The figure in the photo quiz shows a macrophage containing a cluster of Pneumocystis jirovecii trophic forms and one spore of Histoplasma capsulatum. Small trophic forms are about 1.5 to 2 μm in size, with acidophilic nuclei that are clearly identified on the figure, contrary to cytoplasmic shapes that are irregular. The distinctive oval spore, about 2 to 3 μm in size, containing an uncolored vacuole which reduces fungal cytoplasm to a tiny arc, makes it possible to diagnose putative histoplasmosis. This macrophage was the only one that contained both a spore of H. capsulatum and P. jirovecii trophic forms. Two other macrophages containing one spore of H. capsulatum in the absence of P. jirovecii were detected on one slide, indicating the presence of a low fungal burden in the lungs. Cultures of skin biopsy specimens were positive after only 10 days, revealing H. capsulatum, whereas bronchoalveolar lavage (BAL) specimen culture, stored at room temperature, was positive 8 weeks after BAL retrieval, consistent with disseminated histoplasmosis of pulmonary origin. Treatment with liposomal amphotericin B (3 mg/kg/day) followed by itraconazole (200 mg/day) as a secondary prophylaxis provided clinical improvement and absence of relapse until at least January 2005, the month of the patient's departure to another French city. This observation emphasizes the risk of overlooking histoplasmosis in cases of low fungal burden. This low burden, combined with slow fungal growth and the absence of a trained microscopist in an area where histoplasmosis is not endemic, was the cause of a delayed diagnosis. The absence of specific treatment led to dissemination from the lungs. There is evidence that the infection was due to reactivation of latent spores acquired at least 16 months earlier in Martinique. This overseas French territory is an area where histoplasmosis is endemic, in which (i) the incidences of AIDS and histoplasmosis in human immunodeficiency virus (HIV)-infected patients are 0.4/100,000 patients and 1.7% of patients, respectively (1), and (ii) Pneumocystis pneumonia (PCP) and disseminated histoplasmosis represent AIDS-defining illnesses (1, 2). Nonetheless, in Martinique and other areas of endemicity, occurrence of concurrent histoplasmosis and pneumocystosis in AIDS patients has been cited in about 15 instances (3–6) and has not been histologically described until now. (See page 2809 in this issue [doi:10.1128/JCM.01466-12] for photo quiz case presentation.)

Posaconazole as rescue therapy in African histoplasmosis

African histoplasmosis is a granulomatous mycosis caused by Histoplasma capsulatum var. duboisii. Treatment is usually extrapolated from guidelines for classical histoplasmosis, and includes 2–4 weeks of amphotericin B followed by a step-down maintenance therapy with itraconazole. Pediatric usage of posaconazole, an oral second-generation azole, remains off-label, but recent surveys show that it is safe and well tolerated in children. We report a case of disseminated African histoplasmosis in a 12-year-old boy from Guinea-Bissau. Therapy with amphotericin B and itraconazole led to a progressive clinical deterioration. A dramatic and lasting improvement was observed using posaconazole. He completed 12 months of therapy. No relapse was noted during or 3 months after treatment. We report that posaconazole may be a safe and efficacious drug in the salvage management of disseminated AH, either in patients with disease refractory to conventional anti-fungal therapy, or in patients whose serious adverse effects of first-line drugs preclude its use.

Ciprofloxacin shows synergism with classical antifungals against Histoplasma capsulatum var. capsulatum and Coccidioides posadasii

This study evaluated the in vitro interaction between ciprofloxacin (CIP) and classical antifungals against Histoplasma capsulatum var. capsulatum in mycelial (n = 16) and yeast-like forms (n = 9) and Coccidioides posadasii in mycelial form (n = 16). This research was conducted through broth microdilution and macrodilution, according to Clinical Laboratory Standards Institute. Inocula were prepared to obtain from 0.5 × 10(3) to 2.5 × 10(4) cfu ml(-1) for H. capsulatum and from 10(3) to 5 × 10(3) cfu ml(-1) for C. posadasii. Initially, minimum inhibitory concentration (MIC) for each drug alone was determined. Then, these MICs were used as the highest concentration for each drug during combination assays. The procedures were performed in duplicate. For all combination assays, MICs were defined as the lowest concentration capable of inhibiting 80% of visible fungal growth, when compared to the drug-free control. Drug interaction was evaluated by paired sample t-Student test. The obtained data showed a significant MIC reduction for most tested combinations of CIP with antifungals, except for that of CIP and voriconazole against yeast-like H. capsulatum. This study brings potential alternatives for the treatment of histoplasmosis and coccidioidomycosis, raising the possibility of using CIP as an adjuvant antifungal therapy, providing perspectives to delineate in vivo studies.

A case of Histoplasma capsulatum endophthalmitis diagnosed in Italy

Histoplasma capsulatum var. capsulatum is a dimorphic fungus endemic in the eastern United States and most countries of Latin America. Sporadic cases of histoplasmosis have been reported in Europe, mainly in immigrants or people returning from highly endemic areas. We report a case of 64-year-old Italian man with endophthalmitis, an unusual presentation of H. capsulatum infection. The patient shows redness, blurred vision, localized pain in the right eye. H. capsulatum was cultured from a vitreous biopsy and yeast forms were seen at histology.

Evaluation of the genetic diversity of Histoplasma capsulatum var. capsulatum isolates from north-eastern Brazil

Since the beginning of the HIV epidemic, there has been a significant increase in the number of histoplasmosis cases in Ceará, a state in north-east Brazil. The lack of epidemiological data on the genotypes circulating in the north-east region shows the importance of more detailed studies on the molecular epidemiology of Histoplasma capsulatum var. capsulatum in this region. Different molecular techniques have been used to better characterize the genetic profile of H. capsulatum var. capsulatum strains. The aim of this study was to analyse the genetic diversity of H. capsulatum var. capsulatum isolates in Fortaleza, the capital of Ceará, through the sequencing of the internal transcribed spacer (ITS)1-5.8S-ITS2 region, and establish the molecular profile of these isolates, along with strains from south-east Brazil, by RAPD analysis, featuring the different clusters in those regions. The isolates were grouped into two clusters. Cluster 1 included strains from the south-east and north-east regions with separation of isolates into three distinct subgroups (subgroups 1a, 1b and 1c). Cluster 2 included only samples from north-east Brazil. Sequencing of the ITS1-5.8S-ITS2 region allowed the detection of two major clades, which showed geographical correlation between them and their subgroups. Therefore, it can be concluded that the H. capsulatum var. capsulatum isolates from Ceará have a high degree of genetic polymorphism. The molecular data also confirm that populations of this fungus are composed of different genotypes in Brazil and worldwide.

Evaluation of berries of Phytolacca dodecandra for growth inhibition of Histoplasma capsulatum var. farciminosum and treatment of cases of epizootic lymphangitis in Ethiopia

ObjectiveTo evaluate the berries of Phytolacca dodecandra (P. dodecandra) for its effect on Histoplasma capsulatum var. farciminosum (HCF) and for the treatment of cases of epizootic lymphangitis (EL). MethodsSamples were collected from un-ruptured nodules of cases of EL at Debre Zeit and Akaki (central Ethiopia). Mycological culture and isolation of HCF were performed at the Aklilu Lemma Institute of Pathobiology. Phytochemical screening was done for n-butanol extract of P. dodecandra to detect alkaloids, saponins, phenolic compounds and flavonoids. The minimum inhibitory concentrations (MICs) and minimum fungicidal concentrations (MFCs) of aqueous and n-butanol extracts of P. dodecandra against HCF were determined by agar dilution assay. For the in vivo trial, 5% simple ointment was prepared from n-butanol extract and applied topically to 24 (twelve early and twelve moderate) cases of EL. ResultsPhytochemical screening showed that n-butanol extract of P. dodecandra was positive for alkaloids, saponins and phenolic compounds but negative for flavonoids. The MICs of n-butanol and aqueous extracts of P. dodecandra were (0.039%–0.078%) and (0.625%–1.250%), respectively. The MFCs of n-butanol and aqueous extracts of P. dodecandra were (0.078%–0.156%) and (1.250%–2.500%), respectively. The MIC and MFC of ketoconazole (positive control) was (1.200×10−5%–2.500×10−5%) and (5.000×10−5%–1.000×10−4%), respectively while growth was observed on free medium (negative control). From the total of 24 treated cases of EL, 14 (58.3%) responded to treatment; however, 10 (41.7%) did not respond to treatment. There was no significant difference in the degree of response to treatment between early and moderate cases (χ2=0.686; P=0.408). ConclusionsIt can be concluded that n-butanol extract of P. dodecandra demonstrates antifungal effects while the aqueous extract shows no antifungal activity.

BROTE DE HISTOPLASMOSIS DE PRIMOINFECCIÓN EN CINCO HERMANAS

Histoplasmosis capsulati is a fungal infection caused by the dimorphic fungus Histoplasma capsulatum var. capsulatum. It is an endemic mycoses which has a wide distribution in North, Central and South America. Primary infection is acquired through the inhalation of the conidial forms of the fungus present in the environment, especially in caves with bat droppings and soil inhabited by chickens. Clinical features of primary infection are unespecific and may vary from asymptomatic to disseminated forms depending on the proportion of conidae inhalated. Here we present an outbreak of Histoplasma capsulatum primary infection affecting five Argentinian sisters, during a car trip to the north of Argentina, which included the provinces of Santiago del Estero and Tucuman. Four of them presented with mild to moderate acute respiratory disease; the other one developed severe and uncommon manifestations such as erythema nodosum and phlyctenular keratoconjunctivitis. All patients achieved a good clinical outcome and none of them required antifungal therapy.

An Unusual Cutaneous Tumor: African Histoplasmosis following Mudbaths: Case Report and Review

African histoplasmosis, caused by Histoplasma capsulatum var. duboisii, is endemic in Africa. The disease usually involves the skin, subcutaneous tissue, and bones. A case of African histoplasmosis presenting as a cutaneous tumor and non-healing wound in a 66-year-old immunocompetent male residing in Africa, the first ever reported following mudbaths and acupuncture, is hereby reported. Diagnosis was confirmed by means of polymerase chain reaction performed on tissue material. The patient was started on long-term itraconazole therapy and he responded well. African histoplasmosis should be included in the differential diagnosis of non-healing wounds or tumor-like lesions, especially in the context of mudbaths in an endemic area.

Disseminated cutaneous histoplasmosis in an immunocompetent adult

Histoplasmosis, a systemic mycosis caused by the dimorphic fungus Histoplasma capsulatum var capsulatum and Histoplasma capsulatum var duboisii is endemic to many parts of the world. The clinical manifestations range from acute or chronic pulmonary infection to a progressive disseminated disease. After initial exposure to the fungus, the infection is self-limited and restricted to the lungs in 99% of healthy individuals. The remaining 1%, however, progress to either disseminated or chronic disease involving the lungs, liver, spleen, lymph nodes, bone marrow or rarely, the skin and mucous membranes. Mucocutaneous histoplasmosis is frequently reported in patients with acquired immune deficiency syndrome (AIDS), but it is rare in immunocompetent hosts. A 60-year-old male presented with asymptomatic swelling of the hard palate and crusted papules and nodules over the extremities, face and trunk. Clinically, the diagnoses of cutaneous cryptococcosis versus histoplasmosis was considered in this patient. A chest X-ray revealed hilar lymphadenopathy. Enzyme-linked immunosorbent assay (ELISA) for human immunodeficiency virus (HIV) was nonreactive. Skin biopsy revealed multiple tiny intracellular round yeast forms with a halo in the mid-dermis. Culture of the skin biopsy in Sabouraud's dextrose agar showed colonies of Histoplasma capsulatum. Despite an investigation including no evidence of underlying immunosuppression was found, he was started on IV amphotericin-B (0.5 mg/kg/day). However, the patient succumbed to his disease 2 days after presentation. We report a rare case of disseminated cutaneous histoplasmosis in an immunocompetent individual.

Immune Reconstitution Inflammatory Syndrome: Cutaneous and Bone Histoplasmosis Mimicking Leprosy after Treatment

We present a case of disseminated histoplasmosis in a 12-year-old HIV infected boy. This is a rare presentation of Histoplasma capsulatum var. capsulatum which presented as Immune Reconstitution Inflammatory Syndrome with osteoarticular involvement. He was treated with fluconazole for five years and healed with shortening of all the digits.

Imported Acquired Immunodeficiency Syndrome–Related Histoplasmosis in Metropolitan France: A Comparison of Pre–Highly Active Anti-Retroviral Therapy and Highly Active Anti-Retroviral Therapy Eras

Histoplasma capsulatum var. capsulatum infection is rare outside disease-endemic areas. Clinical presentation and outcome of acquired immunodeficiency syndrome-related histoplasmosis are unknown in non-endemic areas with wide access to highly active anti-retroviral therapy (HAART). Retrospective analysis of cases recorded at the French National Reference Center for Mycoses and Antifungals during two decades: pre-HAART (1985-1994) and HAART (1997-2006). Clinical features and outcome of all adults with proven acquired immunodeficiency syndrome-related histoplasmosis were compared between the two periods. One hundred four patients were included (40 during the pre-HAART era and 64 during the HAART era). Diagnosis was established a mean of 62 days after onset of symptoms. One-year overall mortality rates decreased from 53% (pre-HAART era) to 22% (HAART era). Diagnosis during the pre-HAART era and an older age were the only independent factors associated with death. Histoplasmosis is a rare invasive fungal infection outside disease-endemic areas. Its prognosis improved significantly during the HAART era.

An unusual clinical and histologic presentation of disseminated cutaneous histoplasmosis

To the Editor: Histoplasmosis, an infection with the dimorphic saprophytic fungus Histoplasma capsulatum var capsulatum, occurs by either inhalation or direct cutaneous inoculation. It is the most common endemic mycosis in immunosuppressed patients, and disseminated infection in this population may lead to septic shock with multiorgan failure.1 Cutaneous involvement occurs in 5% to 20% of cases of disseminated histoplasmosis, and most commonly presents as papules that favor the face and chest.2-4 Other manifestations include ulcerating plaques, vesicles and pustules, pyoderma gangrenosum–like ulcers, and exanthematous eruptions.

Pulmonary histoplasmosis presenting as chronic productive cough, fever, and massive unilateral consolidation in a 15-year-old immune-competent boy: a case report

IntroductionSevere histoplasmosis is known to be among the AIDS-defining opportunistic infections affecting patients with very low CD4 cell counts in histoplasmosis-endemic areas. Histoplasma capsulatum var. duboisii is common in West and Central Africa, where it occurs in both HIV/AIDS and non-HIV patients. Few cases of life-threatening histoplasmosis in immune-competent individuals have been reported worldwide.Case reportWe describe a case of pulmonary histoplasmosis diagnosed on the basis of autopsy and histological investigations. A 15-year old East African immune-competent boy with a history of smear-positive tuberculosis and a two-year history of rock cutting presented to our hospital with chronic productive cough, fever, and massive unilateral consolidation. At the time of presentation to our hospital, this patient was empirically treated for recurrent tuberculosis without success, and he died on the seventh day after admission. The autopsy revealed a huge granulomatous lesion with caseation, but no acid-fast bacilli were detected on several Ziehl-Neelsen stains. However, periodic acid-Schiff staining was positive, and the histological examination revealed features suggestive of Histoplasma yeast cells.ConclusionSevere pulmonary histoplasmosis should be considered in evaluating immune-competent patients with risk factors for the disease who present with pulmonary symptoms mimicking tuberculosis.

Endemic systemic mycoses: coccidioidomycosis, histoplasmosis, paracoccidioidomycosis and blastomycosis

Endemic deep or systemic mycoses are common in specific geographical areas of the world. Coccidioidomycosis is present in semi-desert areas, histoplasmosis and paracoccidioidomycosis in tropical regions and blastomycosis belongs to temperate climates. The two former are widely distributed in the American continent and some tropical regions of the world; the third is limited to Central and South America, and the last to North America and Central and East Africa. These mycoses all have a similar pathogenesis, as the inoculum enters the host through the respiratory tract. Cutaneous manifestations are secondary to lymphatic and hematogenous dissemination. These deep mycoses are exceptional in Europe. Most cases are observed in returning travelers from endemic areas, aid workers, archaeologists, speleologist and immigrants. However, there have been some autochthonous cases of histoplasmosis due to Histoplasma capsulatum var. capsulatum reported in European countries such as Italy and Germany. In this article, we provide up-to-date epidemiological, clinical, diagnostic and therapeutic data on the four most important imported systemic mycoses in Europe.

Synergistic Effect of Antituberculosis Drugs and Azoles In Vitro against Histoplasma capsulatum var. capsulatum

This study evaluated in vitro interactions of antituberculosis drugs and triazoles against Histoplasma capsulatum. Nine drug combinations, each including an antituberculosis drug (isoniazid, pyrazinamide, or ethambutol) plus a triazole (itraconazole, fluconazole, or voriconazole), were tested against both growth forms of H. capsulatum. Stronger synergistic interactions were seen in isoniazid or pyrazinamide plus triazoles for the mold form and ethambutol plus voriconazole for the yeast-like form. Further studies should evaluate these combinations in vivo.

Infectious Diseases Associated with Caves

In recent times, caving has become increasingly popular, with almost 2 million people visiting national park caves each year in the United States. Although the 2 million tourist visits are extremely low risk, smaller numbers of sport cavers are at risk for some high risk conditions, and expedition cavers are at risk for some obscure infections. Infectious diseases like histoplasmosis, rabies, leptospirosis, and tick-borne relapsing fever may be transmitted by the underground fauna. To reduce the risk of illness or injury while caving, knowledge of potential risks before engaging in this activity is important. Caving preparation needs to be carefully planned and executed, including vaccinations, prophylactic medications, and advice regarding safe conduct and behaviors.

Selection and optimization of PCR-based methods for the detection of Histoplasma capsulatum var. capsulatum

BackgroundCurrent methods for the laboratory diagnosis of histoplasmosis are problematic in terms of their sensitivity, specificity and runtime. ObjectivesThus, in this study, we sought to select and optimize methods for the detection of Histoplasma capsulatum var. capsulatum by polymerase chain reaction (PCR). MethodsThree DNA extraction methods and three PCR methods were evaluated. We optimised the concentration of the components of this PCR reaction and determined its sensitivity and specificity using blood samples to which H. capsulatum had been added. ResultsThe DNA extraction method that yielded the highest-quality DNA used silica membranes (DNeasy Blood & Tissue Kit, Qiagen, Hilden, Germany), and the amplification method with the best detection capacity used a target gene encoding a 100-kDa protein. Our optimisation of the PCR conditions indicated that the reaction works over a significant range of component concentrations; in addition, it was able to detect H. capsulatum better than traditional culture techniques, with a detection limit of only 10 pg of DNA. ConclusionsIn our experimental conditions, the PCR method selected in this work (instead of nested-PCR) is a tool sensitive enough for the diagnosis of histoplasmosis.

Determination of the therapeutic activity of caspofungin compared with the amphotericin B in an animal experimental model of histoplasmosis in hamster (Mesocrisetus auratus)

Background Treatment with amphotericin B is highly effective in histoplasmosis. Caspofungin has shown good activity against Candida and Aspergillus spp . In vitro studies have demonstrated that Histoplasma capsulatum is inhibited by caspofungin. Objectives The purpose of this study was to evaluate the effectiveness of caspofungin in the treatment of histoplasmosis in an animal experimental model. Methods Three strains of Histoplasma capsulatum var. capsulatum were used. Treatment started one week post-inoculation and the animals were randomly assigned to six groups: amphotericin B 6 mg/Kg/d, caspofungin 2 mg/Kg/d, 4 mg/Kg/d, 8 mg/Kg/d and the other two groups received saline solution and dextrose solution. Blood samples for culture were obtained once a week, from day 7 to 35 post-inoculation. One week after the end of the treatment the animals were sacrificed and spleen cultures were performed. Results Blood cultures were negative in all the hamsters which received amphotericin B (100%, P < 0.001); those treated with caspofungin and the control animals presented 30 and 32% of positive cultures respectively ( P = 0.59). Spleen cultures were negative in the animals treated with amphotericin B, while the percentage of positive spleen cultures in the caspofungin groups varied from 25 to 100%, and in the control groups from 35 to 94.8% ( P = 0.07). The statistical analysis of the undiluted cultures showed the use of amphotericin B as the only independent predictor of negative culture ( P < 0.001). Conclusions The efficacy of amphotericin B is well known for the treatment of histoplasmosis, though we could not demonstrate that caspofungin is better than control.

Diagnostic contribution of positron emission tomography with [18F]fluorodeoxyglucose for invasive fungal infections

Optimal staging and evaluation of residual lesions of invasive fungal infections (IFIs) are major challenges in the immunocompromised host. Preliminary data have suggested that [18F]fluorodeoxyglucose ([18F]FDG) uptake may be observed in the course of active invasive fungal infections. The aim of this study was to assess the role of positron emission tomography with [18F]FDG ([18F]FDG-PET) in the diagnosis and staging of IFI. A prospective monocentric study evaluating [18F]FDG-PET in 30 consecutive adults and children with European Organization for Research and Treatment of Cancer/Mycoses Study Group probable or proven IFI was performed. Twenty males and ten females (median age, 45 years (range 6–75 years)) were enrolled. Twenty-six were immunocompromised, as follows: haematological malignancy (18) with allogeneic stem cell transplantation (16/18), solid tumour (three), solid organ transplantation (two), diabetes mellitus (two) and cystic fibrosis (one). IFIs were acute invasive aspergillosis (ten), chronic disseminated candidiasis (ten), zygomycosis (two), black grains eumycetoma (two), pulmonary Histoplasma capsulatum var. capsulatum histoplasmosis (two), and Phomopsis sp. osteoarthritis, Scedosporium apiospermum and Candida krusei spondylodiscitis, and acute pulmonary coccidioidomycosis in one case each. An increased uptake of [18F]FDG was observed in all areas previously identified by computed tomography and/or magnetic resonance imaging to be involved by IFI. In 4/10 chronic disseminated candidiasis cases, [18F]FDG-PET revealed small splenic abscesses that were unapparent on the corresponding computed tomography scan. [18F]FDG uptake disappeared after 6 months of antifungal therapy in three patients with chronic disseminated candidiasis for whom the [18F]FDG-PET was performed to assess the evolution of the disease. [18F]FDG-PET could potentially be useful for the initial diagnosis and staging of IFI. Whether or not [18F]FDG-PET might be useful for assessing the optimal duration of IFI therapy should now be assessed in a specific prospective study.

Seven imported histoplasmosis cases due to Histoplasma capsulatum var. capsulatum: From few weeks to more than three decades asymptomatic period

Histoplasmacapsulatum is a nonendemic fungus in Europe. Epidemiological, clinical biological features and follow-up of seven imported cases in France were reported. These cases underlined the difficulties of such diagnosis in nonendemic areas due to greatly variable asymptomatic period, and lack of specific clinical signs. Thus, anamnesis should be carefully analysed; mucocutaneous signs and immunosuppression should be systematically investigated. Biological diagnosis requires multiple sites sampling and long-term conservation of culture medium.