Prasanna Honnavar

Malassezia arunalokei sp. nov., a Novel Yeast Species Isolated from Seborrheic Dermatitis Patients and Healthy Individuals from India.

ABSTRACT The majority of species within the genus Malassezia are lipophilic yeasts that colonize the skin of warm-blooded animals. Two species, Malassezia globosa and Malassezia restricta, are implicated in the causation of seborrheic dermatitis/dandruff (SD/D). During our survey of SD/D cases, we isolated several species of Malassezia and noticed vast variations within a few lipid-dependent species. Variations observed in the phenotypic characteristics (colony morphology, absence of catalase activity, growth at 37°C, and precipitation surrounding wells containing Tween 20 or Cremophor EL) suggested the possible presence of a novel species. Sequence divergence observed in the internal transcribed spacer (ITS) region, the D1/D2 domain, and the intergenic spacer 1 (IGS1) region of rDNA and the TEF1 gene, PCR-restriction fragment length polymorphism (RFLP) analysis of the ITS2 region, and fluorescent amplified fragment length polymorphism analysis support the existence of a novel species. Based on phenotypic and molecular characterization of these strains, we propose a new species, namely, M. arunalokei sp. nov., and we designate NCCPF 127130 (= MTCC 12054 = CBS 13387) as the type strain.

Association of Malassezia species with psoriatic lesions

The aetiology of psoriasis remains elusive. Among multiple factors hypothesised, association of Malassezia spp. is supported by response to topical antifungals. The objective of this study was to evaluate the association of Malassezia spp. with psoriatic lesion. The subjects included 50 consecutive patients with psoriasis, and 50 age‐ and sex‐matched healthy controls. Samples were collected using scotch tape over one square inch area from the lesional and non‐lesional sites. The isolated Malassezia spp. were identified by phenotypic methods and confirmed by ITS2 PCR‐RFLP and sequencing of D1/D2 region of 26S rDNA. Psoriatic lesions were seen commonly on scalp (28%, 14), chest (22%, 11) and arms (16%, 8). Majority of cases presented with chronic plaque form (76%, 38; P < 0.05). From psoriatic lesions, most frequently isolated Malassezia species was M. furfur (70.6%, 24), followed by M. japonica (11.8%, 4) and M. globosa (8.8%, 3). From healthy individuals M. furfur, M. sympodialis, mixture of M. furfur and M. globosa was isolated in 73.3%, 10% and 16.7% (22, 3 and 5) of cases respectively. The average number of colonies isolated from scalp lesions of the patients was significantly higher (P = 0.03) than healthy areas. Although no strong association of Malassezia species was formed with psoriatic lesion in general, the fungi may play a role in exacerbation of scalp psoriasis.

Disseminated Emmonsia pasteuriana infection in India: a case report and a review

We report here the first case of disseminated Emmonsia pasteuriana infection in a patient with AIDS in India. The patient presented with weight loss, dyspnoea, left‐sided chest pain and multiple non‐tender skin lesions over face and body for 3 months. Disseminated emmonsiosis was diagnosed on microscopic examination and fungal culture of skin biopsy and needle aspirate of lung consolidation. It was confirmed by sequencing internal transcribed spacer region of rDNA, beta tubulin, actin, and intein PRP8. The patient responded to amphotericin B and itraconazole therapy.

Emergence of Magnusiomyces capitatus infections in Western Nepal.

Magnusiomyces capitatus is an emerging opportunistic yeast in the Mediterranean region. We report from Nepal one case of M. capitatus infection and six other cases of colonization/probable infection due to M. capitatus at a tertiary care center. Majority of the patients were immunocompromised, at extreme age, associated with comorbidities, and had history of close contact with livestock and poultry. The isolates were identified by phenotypic and genotypic (ITS and D1/D2 region of 26S rDNA sequence) methods. Molecular typing of the isolates was carried out by amplified fragment length polymorphism. Minimum inhibitory concentration (MIC) of the isolates for amphotericin B, caspofungin, fluconazole, itraconazole, voriconazole, posaconazole, anidulafungin, and micafungin were 2, 0.1-4, 2, 0.12-0.5, 0.12-0.5, 0.25, 1-4, and 1-4 μg/ml, respectively. Presence of M. capitatus infection was not known in Nepal, and the study should alert the clinicians and infectious disease specialists.

Nasal vestibulitis due to Nocardiopsis dassonvillei in a diabetic patient.

Human infection due to Nocardiopsis, an actinomycete, is rare and the majority of those infections are due to Nocardiopsis dassonvillei. This agent has been implicated in cutaneous, pulmonary, eye and disseminated infections. It has never been isolated from the nose or any nasal infection. We report here a rare case of nasal vestibular abscess due to N. dassonvillei in an adult diabetic patient. The bacterium was identified on the basis of morphological and biochemical characteristics, and confirmed by sequencing the 16S rRNA and hsp65 genes. The patient was successfully treated with clarithromycin and levofloxacin. Though N. dassonvillei infections may be rare, the study highlights that it may cause a wide spectrum of disease manifestations, and laboratories should take care to isolate and identify the easily treatable pathogen.

Molecular characterisation and antifungal susceptibility of clinical Trichosporon isolates in India.

In Asian countries, Trichosporon infection is a well‐known disease in Japan. In India, the infection is increasingly recognised. The study was conducted to characterise the clinical Trichosporon isolates from India by phenotypic and molecular techniques. A total of 31 Trichosporon clinical isolates, recovered from patients of 14 hospitals across India were sequenced (ITS and IGS1 regions of rDNA). In vitro drug susceptibility testing of the isolates was performed against amphotericin‐B, fluconazole, itraconazole, voriconazole and posaconazole. IGS1, rather than ITS sequences, correctly identified the isolates: Trichosporon asahii, 20; Trichosporon ovoides, 3; Trichosporon inkin, 2; Trichosporon asteroides, 1; Trichosporon mucoides, 1; Trichosporon loubieri, 1; Trichosporon debeurmannianum, 1; and Trichosporon dermatis, 1. Trichosporon asahii genotype III was the most common type, followed by genotype I and VII. Both these targets did not help to identify one Trichosporon to the species level. Trichosporon debeurmannianum, T. dermatis and T. asteroides were isolated for the first time from a human disease in India. The minimum inhibitory concentrations for voriconazole and posaconazole were within effective range. The study highlights the presence of wide range of Trichosporon species causing infection in India. Voriconazole or posaconazole may be the better drugs to treat such patients.

Molecular identification of clinical Nocardia isolates from India.

The epidemiology of nocardiosis is evolving with increasing number of Nocardia spp. causing human infection. In recent years, molecular techniques have been used to identify Nocardia spp. There are limited data available on the spectrum of Nocardia spp. isolated from clinical samples in India. Here, a molecular study was carried on 30 clinical isolates maintained in our National Culture Collection to evaluate the techniques used for identifying the agents. The isolates were identified by sequencing two promising genes: the 16S rRNA gene and hsp65. Both hsp65 and the 16S rRNA gene could reliably identify 90 % of Nocardia isolates, i.e. N. farcinica, N. cyriacigeorgica, N. brasiliensis, N. otitidiscaviarum, N. amamiensis and N. pneumoniae. The mean percentage dissimilarity of sequence identification was higher using the hsp65 gene (4 %, range 0-7.9 %) compared with the 16S rRNA gene (2.3 %, range 0-8.9 %). Two isolates that showed ambiguous results in both the short segment of the 16S rRNA gene and hsp65 sequences could be resolved by sequencing a larger fragment (∼1000 bp) of the 16S rRNA gene. Both of these isolates were identified as N. beijingensis with similarities of 99.8 and 100 % compared with the standard strain. Genotyping of N. cyriacigeorgica strains was performed using hsp65 gene sequences and compared with previously described genotypes. Our N. cyriacigeorgica isolates belonged to genotype 1 (n = 4) and genotype 2 (n = 2). The present study highlights a wide spectrum of Nocardia spp. in India and emphasizes the need for molecular techniques for identification to the species level.

Phenotypic and molecular characterization of Malassezia japonica isolated from psoriasis vulgaris patients

Malassezia species, which are skin colonizers, are being debated as to their pathogenic role in various cutaneous diseases. Species identification of Malassezia is important as particular species have been implicated in or associated with specific diseases. Malassezia japonica, a relatively newly described species, has not been completely characterized owing to the rarity of its isolation. In the present study we describe phenotypic and molecular characterization of six M. japonica strains isolated from patients with psoriasis vulgaris. In contrast to the physiological and biochemical properties of the M. japonica type strain, CBS9348, all our isolates assimilated Tween 20 and showed positive β-glucosidase activity, and the Cremophor EL utilization test was negative. However, the sequences of the D1/D2 region of rDNA, ITS2 and IGS1 regions of all our isolates clustered with the type strain of M. japonica.

Molecular diagnosis of rhino-orbito-cerebral mucormycosis from fresh tissue samples

Purpose. We aimed to evaluate a PCR‐based technique for the diagnosis of mucormycosis and the identification of fungi from fresh tissue specimens in patients with rhino‐orbito‐cerebral‐mucormycosis (ROCM). Methodology. Fifty cases of ROCM were included in the study. Conventional identification was performed using microscopy and culture. Molecular diagnosis was performed by amplifying the ribosomal DNA using pan‐fungal ITS primers and semi‐nested Mucorales‐specific primers of the 18S region. The amplified products were sequenced to identify the agents. The utility of PCR‐RFLP of the 18S region of rDNA was evaluated to identify the Mucorales. Results. The ROCM cases were diagnosed by the demonstration of aseptate ribbon‐like hyphae in biopsy specimens collected from the patients. Isolation was possible in 24 (48%) samples. The ITS2 PCR confirmed mucormycosis in 27 cases (54%; CI 59.4‐68.2). By comparison, Mucorales‐specific PCR was able to amplify DNA and the sequence enabled the identification of Mucorales speciesin all the patients. PCR‐RFLP of the 18S region of rDNA could only identify the agent to genus level. Conclusion. The molecular technique was able to identify Mucorales species in 26 (42%) cases that were negative by culture. Mucorales‐specific semi‐nested PCR targeting the 18S region is a better technique than ITS2 PCR for diagnosis. PCR‐RFLP of the 18S region helps in identification to genus level.

Invasive pulmonary mycosis due to Chaetomium globosum with false‐positive galactomannan test: a case report and literature review

In this case, the authors report Chaetomium globosum as a cause of invasive pulmonary infection in a patient with Wegeners granulomatosis. Fungal hyphae (KOH and Calcofluor) were seen on direct microscopy of lung biopsy sample and bronchoalveolar lavage (BAL) sample. C. globosum isolated on culture clinched the diagnosis of invasive pulmonary infection by Chaetomium spp. A positive galactomannan of serum and BAL was repeatedly seen and was utilised for follow‐up and as prognostic marker in patient management. The patient was successfully treated with liposomal amphotericin B followed by voriconazole. All the Chaetomium infections reported till date since 1980 are reviewed. Chaetomium spp. with its unique ecology has a hidden clinical potential to cause invasive mould infections.