SciCombinator

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Journal: Medical mycology : official publication of the International Society for Human and Animal Mycology

29

Candida glabrata is an infrequent cause of candidemia in Brazilian public hospitals. We investigated putative differences in the epidemiology of candidemia in institutions with different sources of funding. Prospective laboratory-based surveillance of candidemia was conducted in seven private and two public Brazilian tertiary care hospitals. Among 4,363 episodes of bloodstream infection, 300 were caused by Candida spp. (6.9%). Incidence rates were significantly higher in public hospitals, i.e., 2.42 vs. 0.91 episodes per 1,000 admissions (P< 0.01). Patients in private hospitals were older, more likely to be in an intensive care unit and to have been exposed to fluconazole before candidemia. Candida parapsilosis was more frequently recovered as the etiologic agent in public (33% vs. 16%, P< 0.001) hospitals, whereas C. glabrata was more frequently isolated in private hospitals (13% vs. 3%, P < 0.001). Fluconazole resistance among C. glabrata isolates was more frequent in private hospitals (76.5% vs. 20%, P = 0.02). The 30-day mortality was slightly higher among patients in public hospitals (53% vs. 43%, P = 0.10). Candida glabrata is an emerging pathogen in private institutions and in this setting, fluconazole should not be considered as a safe option for primary therapy of candidemia.

Concepts: Candida parapsilosis, Medicine, Candida glabrata, Yeast, Candida, Tertiary referral hospital, Candidiasis

28

In the framework of a survey on dermatophytoses, 14,619 clinical specimens taken from outpatients with symptoms suggestive of tinea and referred to a Medical Mycology laboratory in Tehran, Iran, were analyzed by direct microscopy and culture. In total, 777 dermatophyte strains recovered in culture were randomly identified by a formerly established RFLP analysis method based on the rDNA ITS regions. For confirmation of species identification, 160 isolates representing the likely entire species spectrum were subjected to ITS-sequencing. Infection was confirmed in 5,175 collected samples (35.4%) by direct microscopy and/or culture. Tinea pedis was the most prevalent type of infection (43.4%), followed by tinea unguium (21.3%), tinea cruris (20.7%), tinea corporis (9.4%), tinea manuum (4.2%), tinea capitis (0.8%) and tinea faciei (0.2%). Trichophyton interdigitale was the most common isolate (40.5%) followed by T. rubrum (34.75%), Epidermophyton floccosum (15.6%), Microsporum canis (3.9%), T. tonsurans (3.5 %) and M. gypseum (0.5%). Other species included M. ferrugineum, T. erinacei, T. violaceum, T. schoenleinii, and a very rare species T. eriotrephon (each one 0.25%). The two strains of T. eriotrephon isolated from tinea manuum and tinea faciei are the second and third reported cases worldwide. Application of DNA-based methods is an important aid in monitoring trends in dermatophytosis in the community.

Concepts: Dermatophyte, Biology, Trichophyton rubrum, Terbinafine, Onychomycosis, Dermatophytosis, Fungal diseases, Mycosis-related cutaneous conditions

28

The duration of the incubation of invasive aspergillosis (IA) remains unknown. The objective of this investigation was to estimate the time interval between aplasia onset and that of IA symptoms in acute myeloid leukemia (AML) patients. A single-centre prospective survey (2004-2009) included all patients with AML and probable/proven IA. Parametric survival models were fitted to the distribution of the time intervals between aplasia onset and IA. Overall, 53 patients had IA after aplasia, with the median observed time interval between the two being 15 days. Based on log-normal distribution, the median estimated IA incubation period was 14.6 days (95% CI; 12.8-16.5 days).

Concepts: Approximation, Estimation, Time, Normal distribution, Leukemia, Acute myeloid leukemia

28

Candidemia is an important cause of morbidity and mortality. As statins interfere with yeast membrane synthesis, we assessed whether use of statins during candidemia may cause differences in clinical outcomes. A retrospective review of 124 candidemia episodes during 2003-2008 in which all-cause and attributable mortality, length of stay and level of care were compared for patients who received and those who did not receive statins. A total of 124 candidemia events were observed involving 14 patients on statins and 110 without statins. Overall mortality in candidemia cases was 46%, but only 2% was attributed to candidemia. No differences were observed in clinical outcomes for the two groups of patients. During the last 2-year period of our study, there were higher rates of candidemia caused by non-C. albicans Candida spp., particularly those due to C. glabrata and C. parapsilosis. In conclusion, statin use during candidemia did not alter mortality, length of stay, or intensive care requirement of our patients, despite higher rates of non-C. albicans Candida species isolated during the last 2 years of our study.

Concepts: Mortality rate, Retrospective, Candida parapsilosis, Candida krusei, Candida glabrata, Statin, Candidiasis, Candida albicans

28

Trichophyton rubrum is a worldwide agent responsible for chronic cases of dermatophytosis which have high rates of resistance to antifungal drugs. Attention has been drawn to the antimicrobial activity of aromatic compounds because of their promising biological properties. Therefore, we investigated the antifungal activity of eugenol against 14 strains of T. rubrum which involved determining its minimum inhibitory concentration (MIC) and effects on mycelial growth (dry weight), conidial germination and morphogenesis. The effects of eugenol on the cell wall (sorbitol protect effect) and the cell membrane (release of intracellular material, complex with ergosterol, ergosterol synthesis) were investigated. Eugenol inhibited the growth of 50% of T. rubrum strains employed in this study at an MIC = 256 μg/ml, as well as mycelial growth and conidia germination. It also caused abnormalities in the morphology of the dermatophyte in that we found wide, short, twisted hyphae and decreased conidiogenesis. The results of these studies on the mechanisms of action suggested that eugenol exerts antifungal effects on the cell wall and cell membrane of T. rubrum. Eugenol act on cell membrane by a mechanism that seems to involve the inhibition of ergosterol biosynthesis. The lower ergosterol content interferes with the integrity and functionality of the cell membrane. Finally, our studies support the potential use of the eugenol as an antifungal agent against T. rubrum.

Concepts: Trichophyton rubrum, Onychomycosis, Miconazole, Ketoconazole, Ergosterol, Antifungal drug, Cell membrane, Athlete's foot

27

Antifungal resistance has been associated with biofilm formation in many microorganisms, but not yet in Malassezia pachydermatis. This saprophytic yeast can cause otitis and dermatitis in dogs and has emerged as an important human pathogen, responsible for systemic infections in neonates in intensive care units. This study aims to evaluate the in vitro antifungal susceptibility of M. pachydermatis strains, in both their planktonic and sessile forms, to fluconazole, miconazole, ketoconazole, itraconazole, posaconazole, terbinafine and voriconazole using the XTT assay and Clinical and Laboratory Standards Institute (CLSI) microdilution method. The minimum inhibitory concentration (MIC) values recorded for each drug were significantly higher for sessile cells relative to planktonic cells to the extent that ≥ 90% of M. pachydermatis strains in their sessile form were classified as resistant to all antifungal agents tested. Data suggest that M. pachydermatis biofilm formation is associated with antifungal resistance, paving the way towards investigating drug resistance mechanisms in Malassezia spp.

Concepts: Fluconazole, Archaea, Ringworm, Antibiotic resistance, Candidiasis, Antifungal drug, Antifungals, Bacteria

27

Cryptococcus neoformans and C. gattii are the etiologic agents of cryptococcosis, a life-threatening disease in both immunocompromised and immunocompetent hosts. Antifungal resistance has been evaluated using different methods, breakpoints, and sizes of test populations and it is an emerging as a significant issue worldwide. A total of 176 (95 clinical and 81 environmental) C. neoformans and eight clinical C. gattii isolates were evaluated to determine the minimal inhibitory concentration (MIC) according to the Clinical and Laboratory Standards Institute method. A total of 10.5% of the C. neoformans clinical isolates were resistant to amphotericin B (AMB), and 6.2% of the environmental isolates were resistant to fluconazole (FLZ). Environmental and clinical isolates presented epidemiologic cut-off values (ECVs) of 64 and 16 to FLZ and 1 and 2 to AMB, respectively. All of the C. gattii isolates showed high susceptibility to most drugs evaluated. Clinical isolates had lower susceptibility than environmental isolates to AMB and itraconazole whereas environmental isolates had lower susceptibility than the clinical isolates to FLZ, voriconazole, and ketoconazole. However, no difference was found in the susceptibility of the two species. The MICs and ECVs to antifungals can help to select the best therapeutic option for tracking epidemiological resistance among clinical and environmental isolates of Cryptococcus spp. around the world.

Concepts: Cryptococcus, Minas Gerais, Antifungals, Cryptococcosis, Flucytosine, AIDS, Fluconazole, Cryptococcus neoformans

27

Microsporum canis, for which the natural hosts are cats and dogs, is the most prevalent zoophilic agent causing tinea capitis and tinea corporis in humans. We present here a diagnostic PCR test for M. canis, since its detection and species identification is relevant to the choice of treatment and to the understanding of a probable source of infection. An M. canis-specific PCR was evaluated using 130 clinical isolates of dermatophytes (including M. canis [n = 15] and 13 other species), 10 yeast or mold isolates, 12 hair and skin samples from animals with or without experimental M. canis infection, and 35 patient specimens, including seven specimens positive for M. canis and 15 dermatophyte negative samples. All pure cultures, animal specimens and clinical samples with M. canis were detected by the PCR test, whereas none of the other fungal isolates or samples without M. canis was negative. This study indicates that the PCR test for M. canis identification applied directly to patient specimens or animal hair, as well as to clinical isolates had 100% specificity and sensitivity.

Concepts: Dermatophyte, Sensitivity and specificity, Biology, Type I and type II errors, Fungal diseases

2

The natural habitat of opportunistic fungal pathogens is outside of the host; therefore, it is crucial to understand their ecology and routes of transmission. In this study, we investigated the presence of black and filamentous fungi in moist indoor environments in the city of Mersin in subtropical Turkey. In total, 177 private dwellings were screened and 893 samples obtained using cotton swabs and moistened with physiological saline from dishwashers, washing machines, refrigerators, bath-tubs, bathroom walls, and shower heads. These were then inoculated onto malt extract agar supplemented with chloramphenicol, followed by incubation at 37°C. Thirty samples (3.4%) were positive for fungi, which were then identified by sequencing the rDNA internal transcribed spacer region. Exophiala dermatitidis was the most common species (23), followed by E. phaeomuriformis (three), Magnusiomyces capitatus (two), and Candida parapsilosis (two). Genotype A of E. dermatitidis (14) was more prevalent than genotypes B (eight) and C (one) and E. phaeomuriformis was also represented by two genotypes. Our findings suggest that dishwashers are a major indoor niche for thermophilic black yeasts. The occurrence of the opportunistic filamentous fungus M. capitatus in dishwashers is consistent with a recent report.

Concepts: Rhizopus, Fungi, Mycotoxin, Evolution, Ascomycota, Biology, Fungus, Yeast

1

Allergic bronchopulmonary aspergillosis (ABPA) complicates asthma and may lead to chronic pulmonary aspergillosis (CPA) yet global burdens of each have never been estimated. Antifungal therapy has a place in the management of ABPA and is the cornerstone of treatment in CPA, reducing morbidity and probably mortality. We used the country-specific prevalence of asthma from the Global Initiative for Asthma (GINA) report applied to population estimates to calculate adult asthma cases. From five referral cohorts (China, Ireland, New Zealand, Saudi Arabia and South Africa), we estimated the prevalence of ABPA in adults with asthma at 2.5% (range 0.72-3.5%) (scoping review). From ABPA case series, pulmonary cavitation occurred in 10% (range 7-20%), allowing an estimate of CPA prevalence worldwide using a deterministic scenario-based model. Of 193 million adults with active asthma worldwide, we estimate that 4,837,000 patients (range 1,354,000-6,772,000) develop ABPA. By WHO region, the ABPA burden estimates are: Europe, 1,062,000; Americas, 1,461,000; Eastern Mediterranean, 351,000; Africa, 389,900; Western Pacific, 823,200; South East Asia, 720,400. We calculate a global case burden of CPA complicating ABPA of 411,100 (range 206,300-589,400) at a 10% rate with a 15% annual attrition. The global burden of ABPA potentially exceeds 4.8 million people and of CPA complicating ABPA ˜ 400,000, which is more common than previously appreciated. Both conditions respond to antifungal therapy justifying improved case detection. Prospective population and clinical cohort studies are warranted to more precisely ascertain the frequency of ABPA and CPA in different locations and ethnic groups and validate the model inputs.

Concepts: Japan, Demography, Saudi Arabia, Aspergillosis, Mathematics, Southeast Asia, Allergic bronchopulmonary aspergillosis, Asthma