Common reservoirs for Penicillium marneffei infection in humans and rodents, China

Cutaneous Penicillium marneffei infection in a patient with idiopathic CD4(+) lymphocytopenia

We describe a case of cutaneous Penicillium marneffei infection in a non-HIV-infected male patient with idiopathic CD4(+) T lymphocytopenia (ICL). The cutaneous lesions were cured after the treatment of itraconazole combined with interleukin-2.

Treatment of Disseminated Talaromyces marneffei with Tracheal Infection: Two Case Reports

Talaromyces marneffei infection involving the trachea presents as diffuse irregular nodules that grow on the tracheal lumen and/or rarely present as concurrent severe eosinophilia. Herein, we report two patients without HIV infection whose main tracheal and/or principal bronchi were involved by T. marneffei infection, which manifested as diffuse proliferative nodules. In case 1, the infection primarily affected the main trachea, resulting in structural cartilage damage, tracheal stenosis, and tracheal absence. In case 2, there were diffuse proliferative nodules in the trachea and bronchi with marked eosinophilia. The final diagnosis was made based on a positive culture from bronchiolar lavage fluid, skin, and tracheal polyps. Case 1 was administered antifungal treatment combined with surgery, but relapse occurred during a 3-month follow-up period. Case 2 was treated by intravenous liposomal amphotericin B combined with atomized inhaled liposomal amphotericin B, and he later showed improvement; there was no relapse during the 12-month period of antifungal treatment. Importantly, atomized inhaled amphotericin B antifungal treatment for T. marneffei infection has never been previously reported.

Role of Rhizomys pruinosus as a natural animal host of Penicillium marneffei in Guangdong, China

Penicillium marneffei, a dimorphic fungus that can cause penicilliosis marneffei, is endemic in Southeast Asia. The only known hosts of P. marneffei are humans and bamboo rats. The aim of our study was to explore the distribution of P. marneffei in bamboo rats, their associated environment and non-rat-associated environments. Totally, 270 samples were collected in Guangdong province of China in 2012; the prevalence of P. marneffei was much higher in samples collected from surrounding areas of burrows (8.2%) than in the samples obtained from non-rat-associated sites (2%) or artificial farms of bamboo rats (0%). There was no difference in P. marneffei isolated rate from different areas of Guangdong province. The infection is prevalent in all rats, and this fungus could be frequently seen in the rats' lungs. This study confirms that bamboo rat is the ecological niche of P. marneffei and hypothesizes that bamboo rats become infected by inhaling aerosolized conidia originating from environmental sources, rather than by the fecal-oral route or transplacental crossing. According to the result of no detection of P. marneffei in the artificial farm, the activity of bamboo rats might be more relevant to the distribution and dissemination of P. marneffei in natural environment.

Effect of Jun N-terminal kinase 1 and 2 on the replication of Penicillium marneffei in human macrophages

Penicillium marneffei (P. marneffei) is a human pathogen which persists in macrophages and threatens the immunocompromised patients. To clarify the mechanisms involved, we evaluated the effect of c-Jun N-terminal kinase 1 and 2 (JNK1/2) on cytokine expression, phagosomal maturation and multiplication of P. marneffei in P. marneffei-stimulated human macrophages. P. marneffei induced the rapid phosphorylation of JNK1/2. Using the specific inhibitor of JNK1/2 (SP600125), we found that the inhibition of JNK1/2 suppressed P. marneffei-induced tumor necrosis factor-α and IL-10 production. In addition, the presence of SP600125 increased phagosomal acidification and maturation and decreased intracellular replication. These data suggest that JNK1/2 may play an important role in promoting the replication of P. marneffei. Our findings further indicate that the pathogen through the JNK1/2 pathway may attenuate the immune response and macrophage antifungal function.

In vitro interactions of calcineurin inhibitors with conventional antifungal agents against the yeast form of Penicillium marneffei

Penicillium marneffei can cause a life-threatening disseminated mycosis in immunocompromised hosts. However, therapeutic strategies for the treatment of this infectious disease are limited. Reports of other fungi suggest that calcineurin inhibitors interact with antifungal agents to improve the treatment outcomes. Here, we evaluated the in vitro interaction of the calcineurin inhibitors cyclosporine A and tacrolimus (FK506) combined with conventional antifungal agents against the pathogenic yeast form of P. marneffei. We demonstrate that the combination of cyclosporine A with amphotericin B, itraconazole, or fluconazole was synergistic for 85, 65, and 30 % of P. marneffei strains, respectively. In contrast, no synergism was observed in all the combinations containing tacrolimus. Furthermore, antagonism was not observed for any combination. In conclusion, the therapeutic potential of a combinatory approach using the calcineurin inhibitor cyclosporine A with conventional antifungal drugs may lead to improved treatment regimens for P. marneffei infections. We propose that mechanism of action studies with cyclosporine A and antifungal agents is needed.

Detection of DOPA-melanin in the dimorphic fungal pathogen Penicillium marneffei and its effect on macrophage phagocytosis in vitro

The fungal pathogen Penicillium marneffei produces melanin-like pigment in vitro. The synthetic pathway of melanin and its possible influence in the protective yeast cells surviving within macrophage cells are not known. In this work, P. marneffei produced brown black pigment in the presence of L-DOPA and black particles were extracted from yeast cells treated with proteolytic enzymes, denaturant and concentrated hot acid. Kojic acid inhibited the brown-black pigment production of P. marneffei yeast grown on brain heart infusion agar. Transmitting electron microscopy showed spherical granular electron-dense particles with an average diameter of 100 nm in a beaded arrangement in the innermost cell wall. Electron-paramagnetic resonance revealed that the black particles contain a stable free radical compound. The UV-visible and Fourier transform infrared spectra of particles extracted from P. marneffei and synthetic DOPA-melanin showed a high degree of similarity. Melanized yeast cells decreased phagocytosis by macrophage cells and increased resistance to intracellular digestion in vitro. These results indicate that P. marneffei can synthesize DOPA-melanin or melanin-like compounds in vitro and suggest that the DOPA-melanin pathway is associated with cell wall structure and enhances the resistance to phagocytosis by macrophages.

Mitochondrial genome of bamboo rat Rhizomys pruinosus

Abstract Bamboo rats are a group of subterranean rodents some of which feed on the roots and shoots of bamboo and other plants. In this study, we sequence the mitochondrial genome of a hoary bamboo rat Rhizomys pruinosus from the south of China. The genome is 16,575 bp in length, and had a gene content of 13 protein coding, 22 tRNAs and 2 rRNAs. The overall base composition is 30.94% T, 24.83% C, 32.21% A and 12.02% G, with an A+T bias of 63.15%. The cytochrome genes were the most conservative genes compared with plateau zokor (Eospalax baileyi) and blind mole rats (Spalax carmeli) in the family Spalacidae. These mitochondrial data are potentially important for the study of molecular evolution, conservation genetics, agricultural technology and epidemiology.

Immunodetection of fungal and oomycete pathogens: established and emerging threats to human health, animal welfare and global food security

Filamentous fungi (moulds), yeast-like fungi, and oomycetes cause life-threatening infections of humans and animals and are a major constraint to global food security, constituting a significant economic burden to both agriculture and medicine. As well as causing localized or systemic infections, certain species are potent producers of allergens and toxins that exacerbate respiratory diseases or cause cancer and organ damage. We review the pathogenic and toxigenic organisms that are etiologic agents of both animal and plant diseases or that have recently emerged as serious pathogens of immunocompromised individuals. The use of hybridoma and phage display technologies and their success in generating monoclonal antibodies for the detection and control of fungal and oomycete pathogens are explored. Monoclonal antibodies hold enormous potential for the development of rapid and specific tests for the diagnosis of human mycoses, however, unlike plant pathology, their use in medical mycology remains to be fully exploited.

Histoplasmosis: a new endemic fungal infection in China? Review and analysis of cases

Histoplasmosis occurs in specific endemic areas, including the mid-western United States, Africa and most of Latin America. Sporadic cases have also been reported in China. The aim of this study was to summarise the epidemiological and clinical data of histoplasmosis in China. We searched the PubMed, CBMdisk and CNKI databases to identify publications related to histoplasmosis in China. Case reports/series on patients with histoplasmosis were included. A comprehensive literature review identified additional cases. The relevant material was evaluated and reviewed. Overall, 300 cases of histoplasmosis were reported in China from 1990 to 2011, and 75% were from regions through which the Yangtze River flows. Most of the patients were autochthonous infections. Of these, 43 patients had pulmonary histoplasmosis and 257 patients had disseminated histoplasmosis. Common underlying diseases included HIV infection, diabetes mellitus and liver diseases. Fever was the most frequently reported clinical feature in disseminated histoplasmosis, followed by splenomegaly and hepatomegaly. Cases of histoplasmosis had a prominent geographical distribution in China. Histoplasmosis should be considered in the diagnosis of patients with relevant symptoms and a history of travel to or residence in these areas.

Clonality despite sex: the evolution of host-associated sexual neighborhoods in the pathogenic fungus Penicillium marneffei

Molecular genetic approaches typically detect recombination in microbes regardless of assumed asexuality. However, genetic data have shown the AIDS-associated pathogen Penicillium marneffei to have extensive spatial genetic structure at local and regional scales, and although there has been some genetic evidence that a sexual cycle is possible, this haploid fungus is thought to be genetically, as well as morphologically, asexual in nature because of its highly clonal population structure. Here we use comparative genomics, experimental mixed-genotype infections, and population genetic data to elucidate the role of recombination in natural populations of P. marneffei. Genome wide comparisons reveal that all the genes required for meiosis are present in P. marneffei, mating type genes are arranged in a similar manner to that found in other heterothallic fungi, and there is evidence of a putatively meiosis-specific mutational process. Experiments suggest that recombination between isolates of compatible mating types may occur during mammal infection. Population genetic data from 34 isolates from bamboo rats in India, Thailand and Vietnam, and 273 isolates from humans in China, India, Thailand, and Vietnam show that recombination is most likely to occur across spatially and genetically limited distances in natural populations resulting in highly clonal population structure yet sexually reproducing populations. Predicted distributions of three different spatial genetic clusters within P. marneffei overlap with three different bamboo rat host distributions suggesting that recombination within hosts may act to maintain population barriers within P. marneffei.

Penicillium marneffei infection: an emerging disease in mainland China

Penicillium marneffei is an emerging pathogenic fungus that can cause a life-threatening systemic mycosis in immunocompromised hosts, especially in patients with AIDS. This infection is endemic in Southeast Asia. With the prevalence of AIDS in this area, the number of patients with systemic penicilliosis marneffei is found to be increasing rapidly in mainland China in recent years. We recently reviewed 668 cases of penicilliosis marneffei in mainland China from January 1984 to December 2009 in cnki, cqvip, CBMdisc and PubMed. We analyzed epidemiological and clinical features, laboratory findings, reaction to therapy and prognosis of the disease. We found that 99.4% of the cases were reported in the southern part of China; among these cases, 42.8% were from Guangxi (286 cases) and 40.6% were from Guangdong province (271 cases). Five hundred and eighty-six cases (87.7%) of penicilliosis marneffei were reported with infection by the human immunodeficiency virus, 25 cases (3.8%) with other immunocompromised diseases, and 57 cases (8.5%) without any documented underlying diseases. Fever, weight loss, anemia, lymphadenopathy, hepatosplenomegaly, respiratory signs and skin lesions were the common clinical manifestations of P. marneffei infections. The 569 cases received antifungal therapy with a mortality of 24.3% (138 cases), 99 cases who had not received antifungal therapy had a mortality of 50.6%. P. marneffei was an emerging pathogenic fungus and become a medical and public health importance in mainland China. The immunocompromised patients should pay more attention to P. marneffei infection in the endemic areas.