Clinical, morphological, and molecular characterization of Penicillium canis sp. nov., isolated from a dog with osteomyelitis

Penicillium and Talaromyces spp. emerging pathogens in dogs since 1990s

Penicillium and Talaromyces spp. are environmental saprophytic molds rarely encountered as infectious agents in humans and animals. This article summarizes the clinical features, treatment, and outcomes of proven infections caused by Penicillium or Talaromyces in four dogs in France. Two dogs had disseminated infections, while the other two had a localized form. All dogs had positive histopathological results showing the presence of hyaline septate hyphae and a positive fungal culture with typical Penicillium conidiophores. Talaromyces georgiensis (n = 1), Penicillium labradorum (n = 2), and Penicillium from section Ramosa series Raistrickiorum (n = 1), were identified based on Internal Transcribed Spacer (ITS) Sanger sequencing. The dogs were initially treated with ketoconazole or itraconazole. Second-line treatment was initiated in three dogs, but after several relapses, the prognosis remained poor. Since the 1990s, 18 cases of Penicillium or Talaromyces infections in dogs have been described worldwide. This series of four reports brings new cases to those already reported in the literature, which are probably underestimated in the world.

Penicillium rhizophilum, a novel species in the section Exilicaulis isolated from the rhizosphere of sugarcane in Southwest Iran

During a survey of species diversity of Penicillium and Talaromyces in sugarcane (Saccharum officinarum) rhizosphere in the Khuzestan province of Iran [1], 195 strains were examined, from which 187 belonged to Penicillium (11 species) and eight to Talaromyces (one species). In the present study, three strains of Penicillium belonging to section Exilicaulis series Restricta, identified as P. restrictum by Ansari et al. [1], were subjected to a phylogenetic study. The multilocus phylogeny of partial β-tubulin, calmodulin and RNA polymerase II second largest subunit genes enabled the recognition of one new phylogenetic species that is here formally described as Penicillium rhizophilum sp. nov. This species is phylogenetically distinct in series Restricta, but it does not show significant morphological differences from other species previously classified in the series. Therefore, we here placed bias on the phylogenetic species concept. The holotype of Penicillium rhizophilum sp. nov. is IRAN 18169F and the ex-type culture is LA30T (=IRAN 4042CT=CBS 149737T).

Bioactive and unusual steroids from Penicillium fungi

Penicillium fungi are represented by various species and can be found worldwide and thrive in a range of environments, such as in the soil, air, and indoors, and in marine environments, as well as food products. Chemical investigation of species of this genus has led to the discovery of compounds from several structural classes with varied bioactivities. As an example, this genus has been a source of bioactive and structurally unusual steroids. The scope of this short review is to cover specialized metabolites of the steroid class and the cytotoxic, antimicrobial, anti-inflammatory as well as phytotoxic activities of these compounds. Other steroids that possess unusual structures, with significant bioactivity yet to determined, will also be discussed to further demonstrate the structural diversity of this compound class from Penicillium fungi, and hopefully inspire the further exploration of such compounds to uncover their activity.

Microbiological aspects of osteomyelitis in veterinary medicine: drawing parallels to the infection in human medicine

Osteomyelitis is a challenging infectious disease affecting humans and animals. It is difficult to diagnose because, in many cases, symptoms are non-specific and, for example in implant-related cases, can appear long time after surgery. In addition to this, it is also difficult to treat due to the need to find the appropriate antibiotic regime and delivery system to reach the site of infection and to avoid development of bacterial resistance. The central purpose of this review is to compare the microbiological aspects of osteomyelitis in human and veterinary medicine, with the aim of improving the microbiological diagnosis and treatment of this infection in animals. Furthermore, the study of osteomyelitis in animals may help to improve the development of animal models for testing new treatments in humans. Host factors and underlying conditions have been studied mainly in humans, although aspects as immunodeficiency have been described in some veterinary cases. Even when Staphylococcus aureus is still considered the most prevalent causing microorganism, this prevalence should be reviewed using molecular diagnostic techniques, and this could affect treatment options. New approaches to treatment include local delivery of antibiotics using different biomaterials, antimicrobial photodynamic therapy, and new antimicrobial compounds. We would like to remark the need of large, high-quality clinical trials and of the development of guides for the diagnosis and treatment of osteomyelitis in different animal species.

A novel chemical marker of tremorgenic mycotoxicosis detected by gas-chromatography/mass-spectrometry

Tremorgenic mycotoxicosis can arise from dietary exposure to secondary metabolite products of various fungal species, particularly those from the Penicillium genus. Although general toxin screens often rely on gas chromatography-mass spectrometry (GC/MS) and well-developed mass spectral library databases, two principal representative Penicillium mycotoxins, roquefortine and penitrem A, are unamenable to GC/MS owing to high molecular weights, low volatilities and/or high thermal instabilities. Reliance on GC/MS screens alone could therefore inadvertently result in failure to collect evidence of exposure to such tremorgenic mycotoxins. In this report we describe a newly discovered tremorgenic marker compound (TMC), the presence of which correlates highly with conclusive exposure to Penicillium toxins in explanation of clinical manifestations of tremorgenic mycotoxicosis. According to detailed mass spectral deconvolution, the compound is 210.0892 molecular weight, and amenable to GC/MS whether chemically underivatized or derivatized by methylation or trimethylsilylation. 1D and 2D NMR (nuclear magnetic resonance) studies on the isolated compound determined the TMC to be the Penicillium product terrestric acid, C11H14O4, which matches the molecular formula determined by high resolution mass spectrometry and thus provides an excellent target for assessment of mycotoxicosis by GC/MS.

Isolation and molecular characterization of causal agent of blue mold on Allium cepa L. and its control by Pennisetum flaccidum Griseb

Blue mold pathogen, isolated from infected Allium cepa L., was identified as a Penicillium species through morphological and molecular characterisation. Internal Transcribed spacer (ITS) region of ribosomal DNA (rDNA) was utilised for DNA sequencing. Basic Local Alignment Search Tool (BLAST) analysis has found the maximum similarity index of the fungus to be 82.39% with the Uncultured Penicillium clone (Accession: MF535522). So, the isolated Penicillium specie is the first reported specie of the genus that infects onion. A phylogenetic tree was constructed to establish a relationship of the isolated fungus with the most relevant species reported on GenBank. Extracts of Pennisetum flaccidum Griseb. were evaluated against the isolated fungus as a potential biocontrol agent. Among the five tested methanol concentrations (0.5%, 1%, 1.5%, 2% and 2.5%) of each plant part (root, inflorescence and foliage), 0.5% root extract showed maximum growth retardation, i.e. 89%. For bioassay-guided fractionation, the root extract was partitioned in n-hexane, chloroform, n-butanol and ethyl acetate. Ethyl acetate (1%) was proved to be the most potent one. Phytochemical screening has confirmed the occurrence of terpenoids, tannins, saponins and alkaloids. The applied molecular approach has deduced that the Penicillium specie collected from Pakistan might be novel. This study can be concluded that P. flaccidum contains potent phytochemicals which might be used as antifungal agent against Penicillium species.

Disseminated Rasamsonia argillacea species complex infections in 8 dogs

Background

Clinical features, treatment, and outcome of opportunistic infections with Rasamsonia spp., a nonpigmented filamentous mold, are not well documented in dogs.

Objectives

Describe clinical, radiographic, pathologic features, and outcome of dogs with disseminated Rasamsonia species complex infections.

Animals

Eight client‐owned dogs.

Methods

Retrospective case series. Medical records were reviewed to describe signalment, history, clinicopathologic and imaging findings, microbiologic and immunologic results, cyto‐ and histopathologic diagnoses, treatment, and outcome.

Results

Presenting complaints were nonspecific with anorexia (n = 5) and back pain (n = 4) most common. Five dogs were German Shepherd dogs. Six dogs had multifocal discospondylitis and 2 had pleural effusion. Six dogs had Rasamsonia piperina and 2 had Rasamsonia argillacea infections with isolates identified using DNA sequencing. Rasamsonia spp. were isolated by urine culture in 5 of 7 dogs. Five of 6 dogs had positive serum Aspergillus galactomannan antigen enzyme immunoassay (EIA) results. Median survival time was 82 days, and 317 days for dogs that survived to discharge. Four died during initial hospitalization (median survival, 6 days). All isolates had low minimum effective concentrations (MECs) to echinocandins with variable minimum inhibitory concentrations (MICs) for azole antifungal drugs.

Conclusions and Clinical Importance

Rasamsonia spp. infections in dogs are associated with multisystemic disease involving the vertebral column, central nervous system, kidneys, spleen, lymph nodes, lungs, and heart. The infection shares clinical features with other systemic mold infections and can be misidentified when using phenotypical microbiologic methods. Molecular techniques are required to identify the organism and guide appropriate antifungal treatment.

Novel Penicillium species causing disseminated disease in a Labrador Retriever dog

This report describes the phenotypic characteristics of a novel Penicillium species, Penicillium labradorum, isolated from a 3-year-old male, castrated, Labrador retriever with disseminated fungal disease. The dog's presenting clinical signs included lethargy, lymphadenopathy, tachypnea, moderate pitting edema, and nonweight bearing lameness associated with the right hind limb. Fine-needle aspirate biopsies from the sublumbar and prescapular lymph nodes were initially examined. The cytologic findings were consistent with pyogranulomatous inflammation with abundant extracellular and phagocytized fungal fragments and hyphae. Based on the morphology of the organisms and lack of endogenous pigment, hyalohyphomycosis was considered most likely, with Fusarium, Penicillium, and Paecilomyces species being considerations. Fungal isolates were obtained via culture of samples from the lymph nodes, and molecular identification testing originally identified an undescribed Penicillium species belonging to the Penicillium section Exilicaulis. BLAST searches and phylogenetic analyses performed approximately 1 year and 9 months after the isolation date revealed an isolate within the Penicillium parvum clade in the Penicillium section Exilicaulis but phylogenetically distant from the other species in the section, thus representing a new species, Penicillium labradorum. Antifungal susceptibility testing was also performed on the isolate and low minimum inhibitory concentrations were observed with terbinafine, voriconazole, and posaconazole, while in vitro resistance was observed with fluconazole. The dog had been previously treated with fluconazole, itraconazole, amphotericin B lipid complex, voriconazole, and terbinafine. Approximately 587 days after the initial diagnosis, the dog was euthanized due to worsening of clinical signs and concerns for quality of life.

Granulomatous polyarthritis caused by Talaromyces georgiensis in a dog

A 6-y-old, 3.5-kg, spayed female Toy Poodle was presented with left forelimb lameness of 2-d duration. Two months before the initial presentation, radiography showed osteolysis of the medial epicondyle of the left humerus, and the left forelimb was amputated. Grossly, the articular villi of the elbow joint were markedly thickened, and the articular cartilage surfaces of the distal humerus and proximal radius had partial erosion. Histologically, granulomatous arthritis and osteomyelitis characterized by the presence of abundant macrophages containing numerous fungi were observed. ITS and β-tubulin sequences amplified from the isolate from the specimen were 100% and 99% identical to type strain UTHSC D16-145^T of Talaromyces georgiensis, respectively. Canine osteoarthritis caused by T. georgiensis has not been reported previously, to our knowledge.

Taxonomy and evolution of Aspergillus, Penicillium and Talaromyces in the omics era - Past, present and future

Aspergillus, Penicillium and Talaromyces are diverse, phenotypically polythetic genera encompassing species important to the environment, economy, biotechnology and medicine, causing significant social impacts. Taxonomic studies on these fungi are essential since they could provide invaluable information on their evolutionary relationships and define criteria for species recognition. With the advancement of various biological, biochemical and computational technologies, different approaches have been adopted for the taxonomy of Aspergillus, Penicillium and Talaromyces; for example, from traditional morphotyping, phenotyping to chemotyping (e.g. lipotyping, proteotypingand metabolotyping) and then mitogenotyping and/or phylotyping. Since different taxonomic approaches focus on different sets of characters of the organisms, various classification and identification schemes would result. In view of this, the consolidated species concept, which takes into account different types of characters, is recently accepted for taxonomic purposes and, together with the lately implemented 'One Fungus - One Name' policy, is expected to bring a more stable taxonomy for Aspergillus, Penicillium and Talaromyces, which could facilitate their evolutionary studies. The most significant taxonomic change for the three genera was the transfer of Penicillium subgenus Biverticillium to Talaromyces (e.g. the medically important thermally dimorphic 'P. marneffei' endemic in Southeast Asia is now named T. marneffei), leaving both Penicillium and Talaromyces as monophyletic genera. Several distantly related Aspergillus-like fungi were also segregated from Aspergillus, making this genus, containing members of both sexual and asexual morphs, monophyletic as well. In the current omics era, application of various state-of-the-art omics technologies is likely to provide comprehensive information on the evolution of Aspergillus, Penicillium and Talaromyces and a stable taxonomy will hopefully be achieved.

Pneumonia due to Talaromyces marneffei in a Dog from Southern Brazil with Concomitant Canine Distemper Virus Infection

The pathological and molecular findings associated with Talaromyces marneffei-induced pneumonia with concomitant infection by canine distemper virus (CDV) are described in a dog. The principal pathological alteration occurred in the lungs. Histopathology confirmed multifocal granulomatous pneumonia associated with numerous intralesional and intracellular septate fission cells consistent with T. marneffei. A molecular assay designed to amplify a partial fragment of the 18S rRNA gene of T. marneffei provided positive results from two fungal cultures derived from the lung. Sequencing and phylogenetic analyses confirmed the results of polymerase chain reaction (PCR). Furthermore, antigens of the CDV N protein were identified within the bronchial epithelium by immunohistochemistry and a PCR assay amplified the CDV N gene from hepatic and pulmonary fragments. Collectively, the pathological and molecular techniques confirmed a diagnosis of T. marneffei-induced pneumonia with concomitant infection by CDV. These findings represent the first description of pulmonary penicilliosis in the dog and extend the geographical niche of this emerging infectious pathogen. In this case, infection by CDV may have induced immunosuppression, which facilitated the development of pulmonary penicilliosis.

Identification and Antifungal Susceptibility of Penicillium-Like Fungi from Clinical Samples in the United States

Penicillium species are some of the most common fungi observed worldwide and have an important economic impact as well as being occasional agents of human and animal mycoses. A total of 118 isolates thought to belong to the genus Penicillium based on morphological features were obtained from the Fungus Testing Laboratory at the University of Texas Health Science Center in San Antonio (United States). The isolates were studied phenotypically using standard growth conditions. Molecular identification was made using two genetic markers, the internal transcribed spacer (ITS) and a fragment of the β-tubulin gene. In order to assess phylogenetic relationships, maximum likelihood and Bayesian inference assessments were used. Antifungal susceptibility testing was performed according to CLSI document M38-A2 for nine antifungal drugs. The isolates were identified within three genera, i.e., Penicillium, Talaromyces, and Rasamsonia The most frequent species in our study were Penicillium rubens, P. citrinum, and Talaromyces amestolkiae The potent in vitro activity of amphotericin B (AMB) and terbinafine (TRB) and of the echinocandins against Penicillium and Talaromyces species might offer a good therapeutic alternative for the treatment of infections caused by these fungi.

A phylogenetic revision of Penicillium sect. Exilicaulis, including nine new species from fynbos in South Africa

A survey of the fynbos biome in South Africa resulted in the isolation of 61 Penicillium species from Protea repens infructescences, air, and soil samples. Fourteen of these belong to Penicillium sect. Exilicaulis and therefore we considered it an opportunity to re-evaluate the taxonomy of the section. Phylogenetic comparisons of the ITS, β-tubulin, calmodulin and RPB2 gene regions of the 76 section Exilicaulis species, revealed 52 distinct species, including nine new species from fynbos. Morphological comparisons confirmed the novelty for most of these, however, new species closely related to P. rubefaciens did not show significant or consistent morphological differences and we thus placed a bias on phylogenetic data applying the Genealogical Concordance Phylogenetic Species Recognition (GCPSR) concept. In this paper we describe the nine new species and update the accepted species list and resolve synonyms in the section. Importantly, we reveal that P. citreosulfuratum is the correct name for the clade previously considered to represent P. toxicarium fide Serra et al. (2008). The nine new species are: Penicillium atrolazulinum, P. consobrinum, P. cravenianum, P. hemitrachum, P. pagulum, P. repensicola, P. momoii, P. subturcoseum, and P. xanthomelinii spp. nov.