Comparative in vitro activities of seven antifungal drugs against clinical isolates of Candida parapsilosis complex.

OBJECTIVE: Candida parapsilosis species complex, an important set of non-albicans Candida species, is known to cause candidaemia particularly in neonates and infants. However, the incidence has increased in recent years, owing to higher numbers of at individuals at risk for these infections. Our objective was to evaluate the in vitro susceptibility of clinical isolates of C. parapsilosis complex isolates from Iran to seven antifungal drugs. MATERIAL AND METHODS: One hundred-one clinical isolates of C. parapsilosis species complex cultured from humans were included. Species identification had been previously confirmed by combined phenotypic characteristics, matrix-assisted laser desorption ionization-time of flight mass spectrometry-based assay and reconfirmed by DNA sequence analysis of the ITS rDNA region and D1/D2 gene. Minimum inhibitory concentrations (MICs) for amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, micafungin and anidulafungin were determined against well-characterized isolates by broth microdilution susceptibility testing according to the CLSI M27-A3 guideline. RESULTS: Species identifications were performed on 101 isolates, of which 88 (87.2%) C. parapsilosis sensu stricto and 13 (12.8%) C. orthopsilosis. Amphotericin B and posaconazole were the most active drugs with 100% of isolates being wild-type (WT). Voriconazole and micafungin, 99% of isolates were WT. The low activity was recorded for fluconazole and itraconazole with 93.1% and 89.1% of isolates being WT, respectively. At the species level, all Candida parapsilosis sensu stricto isolates were WT to amphotericin B and posaconazole and all Candida orthopsilosis isolates were WT to amphotericin B, voriconazole, posaconazole, anidulafungin and micafungin. In contrast, the highest rate of non-WT was observed in C. orthopsilosis to itraconazole (4 of 13, 30.8%). CONCLUSIONS: Although almost all of the tested drugs demonstrated potent activity against C. parapsilosis species complex, it seems that more especially C. orthopsilosis isolates had decreased susceptibility to itraconazole. Further studies are needed to determine how these findings may switch into in vivo efficacy.

Methods for identification of Candida auris, the yeast of global public health concern: A review.

Candida auris has recently emerged as a fungus able to cause severe infections, especially bloodstream infections with high mortality rates. This multi-drug-resistant yeast has the capacity of persistence on environmental surfaces, and has been reported to cause hospital-acquired infections. The development of faster and inexpensive tools for identification is critical to controlling, preventing and establishing early diagnosis of this emerging pathogen. Identification of C. auris by use of conventional laboratory methods is challenging, and it is commonly misidentified as other Candida species. Less expensive, reliable DNA-based tests have been used for identifying C. auris in environmental and clinical samples. Matrix-assisted laser desorption ionization-time of flight mass spectrometry is also a useful tool for identification of cultured isolates. This review provides a succinct overview of the available methods for identification of C. auris with particular emphasis on their relative advantages and drawbacks.

Evaluation of PCR-reverse line blot hybridization assay for simultaneous identification of medically important saprophytic fungi.

BACKGROUND: In immunocompromised patients suffering from invasive fungal infections, rapid identification of fungal species is important since the appropriate treatment is usually related to the responsible species. We describe here, an assay based on combination of PCR and reverse line blot hybridization (PCR/RLB) for differentiation causative agent of fungal infections. MATERIALS AND METHODS: We performed PCR/RLB assay on 10 reference strains, which include Aspergillus species (A. fumigatus, A. flavus, A. niger, A. terreus, and A. clavatus), Mucor circnelloides, Rhizopus oryzae, Alternaria alternata, Cladosporium herbarum, and Fusarium solani. Besides, twenty-two clinical specimens from patients with proven fungal infections were analyzed for the identification of species. The obtained results were then compared with the results of culture and sequence analysis. RESULTS: The fungal species-specific oligonucleotide probes were able to distinguish between all species represented in this study with the exception of cross-reactivity between A. niger and A. fumigatus species. Two specimens, which were represented as mixed fungi in culture, were identified properly by this method. Results of the RLB assay were concordant with the culture and ITS sequencing results. CONCLUSION: Our result demonstrate that the RLB assay potentially is suitable for rapid and simultaneous identification of variety fungal pathogens directly from culture as well as from clinical specimens.

Coexistence of aspergilloma and pulmonary hydatid cyst in an immunocompetent individual.

Echinococcosis is a zoonotic disease caused by Echinococcus granulosus sensu lato. The liver and lungs are the most commonly sites of infections, but involvements of other organs were also observed. Recently, the coinfection of pulmonary hydatid cyst with aspergilloma has been reported in the literature. Herein, we report a successful treatment of coinfection of cystic echinoccosis with aspergilloma due to Aspergillus flavus in a 34-year-old female. In vitro antifungal susceptibility tests revealed that the MIC values for antifungals employed in this case were posaconazole (0.031µg/ml), itraconazole (0.125µg/ml), voriconazole (0.25µg/ml), and amphotericin B (1µg/ml). The minimum effective concentration for caspofungin was 0.008µg/ml. This coexistence of active pulmonary echinococcosis and aspergillosis is being reported because of its rarity and clinical importance for its management.

First case of superficial infection due to Naganishia albida (formerly Cryptococcus albidus) in Iran: A review of the literature.

BACKGROUND AND PURPOSE: Naganishia albida (formerly Cryptococcus albidus) is a non-neoformans cryptococcal species rarely isolated as a human pathogen. CASE REPORT: Herein, we present the case of a 26-year-old Iranian man with a superficial cutaneous lesion in the axilla. The initial treatment for pityriasis versicolor by clotrimazole was unsuccessful. We performed skin sampling based on the standard protocol and conducted further investigations by the conventional laboratory tests and molecular analysis of the skin samples. All the mentioned analyses revealed N.albida as the causative agent of infection. The minimum inhibitory concentration (MIC) analysis was carried out for the isolated agent, and the patient was treated using 100 mg daily of oral itraconazole. CONCLUSION: N. albida can be the causative agent of some superficial infections. This is the first report on the successful detection and treatment of a superficial skin infection due to N. albida by oral itraconazole.

Pseudohyphae formation in Candida glabrata due to CO2 exposure.

BACKGROUND AND PURPOSE: Formation of pseudohyphae is considered a virulence factor in Candida species. Generally, Candida glabrata grows as budding yeast cells; however, reports illustrated that C. glabrata could form pseudohyphal cells in response to some stimuli. In this study, we provided insight into the ability of C. glabrata in forming pseudohyphal cells under different levels of carbon dioxide (CO2). MATERIALS AND METHODS: Candida glabrata reference strain (ATCC 90030) was used in this study. Yeast samples were cultured on Sabouraud dextrose broth (SDB) medium and incubated under 3%, 5%, and 10% CO2 levels for 24, 48 and 72 h. Control cultures were prepared without CO2 pressure for three days. The possibility of pseudohyphae and mycelium formation in C. glabrata was investigated. RESULTS: The results of this study revealed that the most branching filament-like cells were obtained at high CO2 pressure (10%) after 72 h. After three days of low CO2 pressure (3%), only yeast and budding cells were observed without any pseudohyphae formation. CONCLUSION: CO2 could act as a stimulus and induced formation of pseudohyphae in Candida glabrata yeast cells.

Epidemiology and molecular characterization of Cryptococcus neoformans isolated from pigeon excreta in Mazandaran province, northern Iran.

OBJECTIVE: The aims of this study were to verify the presence of Cryptococcus neoformans in pigeon excreta in Mazandaran province, Iran, to identify the varieties of the C. neoformans isolates using D1/D2 and IGS sequencing, and determining the presence of the two mating types: α and a. MATERIALS AND METHODS: Four hundred pigeon droppings samples were collected from 15 different cities in Mazandaran province over a period of 1 year (February 2010-March 2011). Identification of C. neoformans was determined based on growing brown colonies on Niger seed agar (NSA) and biochemical characteristics. We used MATα and MATa specific primers for determining mating type and sequence analysis of the D1/D2 and intergenic spacer regions were done. RESULTS: Out of 400 samples, 20 samples (5%) were positive for C. neoformans and all of these isolates were α mating types. Sequence analysis of polymerase chain reaction (PCR) amplicons of D1/D2 regions revealed that all of the isolates were C. neoformans var. grubii except two isolates that were C. neoformans var. neoformans. CONCLUSION: Our results reinforced that the pigeon excreta is a favorable environment rich in nitrogen and supports the growth of C. neoformans and the pigeon could play an important role in spread of this organism.