ABSTRACT
Objectives: In recent years, the incidence of invasive fungal infections has increased, resulting in considerable morbidity and mortality, particularly among immunocompromised individuals. Potential challenges in treating these infections with the few existing antifungal agents highlight the urgency of developing new ones. Here, we evaluated six alkyl polyamine compounds (APCs), not previously reported as antifungal drugs to our knowledge, that could deprive fungi of essential transition metals. Methods: The APC with confirmed antifungal activity against Candida spp. was analysed by using transcriptomics, followed by metal-addition experiments, mass spectrometric analyses and intracellular zinc quantification with a fluorescent probe. Results: A cyclic APC with three pyridylmethyl groups, APC6, had high antifungal activity against a wide range of Candida species, including MDR Candida auris. We conclusively demonstrated that APC6 was able to capture zinc within fungal cells. APC6 not only exhibited activity against C. auris as a single agent but also enhanced the efficacy of an azole antifungal agent, voriconazole, in vitro and in vivo. APC6 disrupted the biofilms formed by Candida species. Conclusions: This zinc-chelating compound has potential as an antifungal agent, and the control of zinc levels in Candida species could be a powerful approach to treating drug-resistant candidiasis.
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This case report presents an unusual occurrence of pulmonary aspergillosis caused by Aspergillus sydowii in a 26-year-old male patient. The patient is from Nepal and had no significant medical history and was previously in good health. Chest computed tomography (CT) scans revealed localized bronchiectasis primarily in the left inferior lingular segment and the left lower lobe. Subsequently, bronchial lavage fluid was collected, and a comprehensive culture examination was conducted to confirm the cause of the infection. While Aspergillus fumigatus typically predominates as the cause of pulmonary aspergillosis, our bronchial lavage fluid culture revealed the presence of a filamentous fungus, identified as Aspergillus sydowii through molecular analysis. Thus, we conclusively identified this particular strain of fungus as the etiological factor behind the patient's condition. Notably, pulmonary aspergillosis due to Aspergillus sydowii is exceedingly rare, and we present this case alongside relevant prior data for comprehensive clinical insight. This case underscores the clinical significance of Aspergillus sydowii as a fungal pathogen, emphasizing the importance of early recognition and managing fungal infections.
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The increasing incidence of candidemia and the emergence of drug-resistant Candida species are major concerns worldwide. Therefore, long-term surveillance studies are required. Here, we provide one of the largest longitudinal overviews of the trends in the prevalence of Candida species using national data of 57 001 candidemia isolates obtained from > 2000 hospitals for the 2010-2019 period in the Japan Nosocomial Infections Surveillance database. The proportion of Candida species, except Candida krusei and Candida guilliermondii, was almost the same during the study period. The proportion of C. guilliermondii surpassed that of C. krusei in 2014. The incidence of candidemia due to C. albicans (P < 0.0001), C. parapsilosis (P = 0.0002), and C. tropicalis (P < 0.0001) have decreased significantly over this period. Azole susceptibility of C. tropicalis was low, with 17.8% of isolates resistant to fluconazole and 13.5% resistant to voriconazole. The micafungin susceptibility of C. glabrata was low, with 8.0% of isolates showing resistance. The resistance rate of C. krusei toward amphotericin B fluctuated considerably (between 3.2% and 35.7%) over this period. The incidence rate of candidemia caused by C. parapsilosis and C. guilliermondii in hospitals responsible for bone marrow transplantation was significantly higher than that in other hospitals. Overall, our study suggests that in Japan, the species distribution of Candida was almost the same in this period and similar to that reported in North America and Europe. A relatively high resistance to azoles and micafungin was observed in C. glabrata, C. tropicalis, and C. krusei isolates, which require continued surveillance.
This study verifies that the proportion of Candida species in Japan was almost the same from 20102019. A relatively higher resistance to azoles and micafungin was observed for C. glabrata, C. tropicalis, and C. krusei isolates.
Subject(s)
Candida , Candidemia , Amphotericin B , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Azoles , Candida albicans , Candida glabrata , Candida parapsilosis , Candida tropicalis , Candidemia/microbiology , Candidemia/veterinary , Drug Resistance, Fungal , Fluconazole , Humans , Japan/epidemiology , Micafungin , Microbial Sensitivity Tests/veterinary , VoriconazoleABSTRACT
The uptake of cholesterol from the host is closely linked to the proliferation of pathogenic fungi and protozoa during infection. For some pathogenic fungi, cholesterol uptake is an important strategy for decreasing susceptibility to antifungals that inhibit ergosterol biosynthesis. In this study, we show that Candida glabrata ERG25, which encodes an enzyme that demethylates 4,4-dimethylzymosterol, is required for cholesterol uptake from host serum. Based on the screening of C. glabrata conditional knockdown mutants for each gene involved in ergosterol biosynthesis, ERG25 knockdown was found to decrease lethality of infected mice. ERG25 knockdown impairs the plasma membrane localization of the sterol importer Aus1p, suggesting that the accumulated 4,4-dimethylzymosterol destabilizes the lipid domain with which Aus1p functionally associates. ERG25 knockdown further influences the structure of the membrane compartment of Can1p (MCC)/eisosomes (ergosterol-rich lipid domains), but not the localization of the membrane proteins Pma1p and Hxt1p, which localize to sterol-poor domains. In the sterol-rich lipid domain, Aus1p-contining domain was mostly independent of MCC/eisosomes, and the nature of these domains was also different: Ausp1-contining domain was a dynamic network-like domain, whereas the MCC/eisosomes was a static dot-like domain. However, deletion of MCC/eisosomes was observed to influence the localization of Aus1p after Aus1p was transported from the endoplasmic reticulum (ER) through the Golgi apparatus to the plasma membrane. These findings suggest that ERG25 plays a key role in stabilizing sterol-rich lipid domains, constituting a promising candidate target for antifungal therapy.
ABSTRACT
Background: Candida glabrata is an emerging fungal pathogen in immune-compromised hosts. Previously undetected C. glabrata isolates were successfully recovered from clinical specimens by adding sterols to the growth medium. The clinical isolates are unable to synthesize ergosterol but can take up exogenous sterols under aerobic conditions. Objectives: This study characterizes the sterol-auxotrophic C. glabrata strains, examines the mutation(s) in sterol synthesis genes, characterizes the drug susceptibility and evaluates the virulence in a mouse infection model. Methods: Drug susceptibility of the C. glabrata strains was evaluated in a sterol-supplemented medium. The coding sequences of the sterol synthesis genes were analysed in six sterol-auxotrophic strains of C. glabrata. The fungal burden of mice infected with C. glabrata strain was determined. Results: The sterol-auxotrophic strains showed high-level resistance to both azoles and amphotericin B when sterols were supplied in the test medium. Additionally, the strains harbour missense mutations in either ERG1 or ERG7. Significant differences in fungal burden were not observed between the sterol-auxotrophic strain and the sterol-competent strain with the mice infection models. Conclusions: The sterol-auxotrophic C. glabrata strain investigated in this study seemed to maintain intact virulence, probably due to the supply of exogenous sterols from host organ(s). This suggests that exogenous sterol uptake develops antifungal resistance during infection.
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BACKGROUND: Although oxygen concentrations inside of the human body vary depending on organs or tissues, few reports describe the relationships between biofilm formation of Candida species and oxygen concentrations. In this study, we investigated the biofilm-forming capabilities of Candida species under various oxygen conditions. METHODS: We evaluated the adhesion and biofilm formation of Candida albicans and C. tropicalis under aerobic, microaerobic (oxygen concentration 5%), or anaerobic conditions. We also examined how oxygen concentration affects adhesion/maturation by changing adhesion/maturation phase conditions. We used crystal violet assay to estimate the approximate biofilm size, performed microscopic observation of biofilm morphology, and evaluated adhesion-associated gene expression. RESULTS: The adhered amount was relatively small except for a clinical strain of C. tropicalis. Our biofilm-formation analysis showed that C. albicans formed a higher-size biofilm under aerobic conditions, while C. tropicalis favored microaerobic conditions to form mature biofilms. Our microscopic observations were consistent with these biofilm-formation analysis results. In particular, C. tropicalis exhibited more hyphal formation under microaerobic conditions. By changing the adhesion/maturation phase conditions, we represented that C. albicans had favorable biofilm-formation capability under aerobic conditions, while C. tropicalis showed enhanced biofilm formation under microaerobic adhesion conditions. In good agreement with these results, the C. tropicalis adhesion-associated gene expression tended to be higher under microaerobic or anaerobic conditions. CONCLUSIONS: C. albicans favored aerobic conditions to form biofilms, whereas C. tropicalis showed higher biofilm-formation ability and promoted hyphal growth under microaerobic conditions. These results indicate that favorable oxygen conditions significantly differ for each Candida species.
Subject(s)
Candida albicans , Candida , Biofilms , Candida/genetics , Candida albicans/genetics , Candida tropicalis/genetics , Humans , OxygenABSTRACT
This study was designed to evaluate the prevalence of antifungal resistance, genetic mechanisms associated with in vitro induction of azole and echinocandin resistance and genotyping of Candida krusei, which is intrinsically resistant to fluconazole and is recovered from clinical and nonclinical sources from different countries. Our results indicated that all the isolates were susceptible or had the wild phenotype (WT) to azoles, amphotericin B, and only 1.27% showed non-WT for flucytosine. Although 70.88% of the isolates were resistant to caspofungin, none of them were categorized as echinocandin-resistant as all were susceptible to micafungin and no FKS1 hot spot 1 (HS1) or HS2 mutations were detected. In vitro induction of azole and echinocandin resistance confirmed the rapid development of resistance at low concentrations of fluconazole (4 µg/ml), voriconazole (0.06 µg/ml), and micafungin (0.03 µg/ml), with no difference between clinical and nonclinical isolates in the resistance development. Overexpression of ABC1 gene and FKS1 HS1 mutations were the major mechanisms responsible for azole and echinocandin resistance, respectively. Genotyping of our 79 isolates coupled with 217 other isolates from different sources and geography confirmed that the isolates belong to two main subpopulations, with isolates from human clinical material and Asia being more predominant in cluster 1, and environmental and animals isolates and those from Europe in cluster 2. Our results are of critical concern, since realizing that the C. krusei resistance mechanisms and their genotyping are crucial for guiding specific therapy and for exploring the potential infection source.
Subject(s)
Azoles , Echinocandins , Animals , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Azoles/pharmacology , Drug Resistance, Fungal/genetics , Echinocandins/pharmacology , Genotype , Microbial Sensitivity Tests , Pichia , PrevalenceABSTRACT
BACKGROUND: Vulvovaginal candidiasis is a common superficial candidiasis; however, a host's immunological mechanism against vaginal Candida infection remains unknown. OBJECTIVES: In this study, we aimed to elucidate the effect of iNKT cell activation on vulvovaginal candidiasis. METHODS: Using a vulvovaginal candidiasis model with estrogenized mice, we evaluated the fungal burden and number of leukocyte infiltrations in the vaginal lavage of wild-type C57BL/6J mice after Candida albicans inoculation. One day before C. albicans inoculation, α-galactosylceramide (the α-GalCer group) or sterile phosphate-buffered saline (the sham group) was intraperitoneally injected into the mice. We also evaluated the level of antimicrobial peptide S100A8 in the vaginal lavage and analyzed the correlation between S100A8 concentration and the number of vaginal leukocyte infiltrations. Moreover, the number of uterine and vaginal immune cells were evaluated using flow cytometry. RESULTS: The number of vaginal leukocyte infiltrations was significantly higher in the α-GalCer group than in the sham group 3 days after C. albicans inoculation. In addition, the fungal burden was significantly lower in the α-GalCer group than the sham group at 7 days after inoculation. In the analysis of S100A8 concentration of vaginal lavage, there were no significant differences between these two groups, although S100A8 concentration and the number of vaginal leukocyte infiltrations were positively correlated in the α-GalCer group. Moreover, the number of vaginal iNKT cells, NK cells and CD8+ T-cells was significantly higher in the α-GalCer group 3 days after inoculation. CONCLUSIONS: α-GalCer-stimulated iNKT cells likely play a protective role against vulvovaginal candidiasis.
Subject(s)
Candidiasis, Vulvovaginal , Animals , Candida albicans , Female , Galactosylceramides , MiceABSTRACT
Histoplasmosis is a fungal infection caused by Histoplasma capsulatum, and Japan is considered a non-endemic area for histoplasmosis. Most patients diagnosed with histoplasmosis in the past usually have exposure to caves and bat guano with travel history to endemic areas. Therefore, travel history and risk activities should be comprehensively assessed when suspecting histoplasmosis because this important information may be overlooked. Although few, possibilities of indigenous cases have also been suggested. Moreover, it is assumed that the number of travelers and endemic mycoses has decreased with the recent coronavirus disease 2019 epidemic. However, clinicians should carefully consider the differential diagnosis of histoplasmosis for travelers traveling to endemic areas. In this case report, we describe an immunocompetent Japanese woman who developed histoplasmosis due to a history of travel to an endemic country. Our case report suggests that clinicians should not exclude histoplasmosis from the differential diagnosis even in the absence of risk features such as activities or immunodeficiencies during travel.
Subject(s)
COVID-19 , Histoplasmosis , Adult , Female , Histoplasma , Histoplasmosis/diagnosis , Histoplasmosis/drug therapy , Humans , Japan , SARS-CoV-2 , South America , TravelABSTRACT
BACKGROUND: Candida auris infections have recently emerged worldwide, and this species is highly capable of colonization and is associated with high levels of mortality. However, strain-dependent differences in colonization capabilities and virulence have not yet been reported. OBJECTIVES: In the present study, we aimed to clarify the differences between clinically isolated invasive and non-invasive strains of C. auris. METHODS: We evaluated colonization, dissemination, and survival rates in wild C57BL/6J mice inoculated with invasive or non-invasive strains of C. auris under cortisone acetate immunosuppression, comparing with those of Candida albicans and Candida glabrata infections. We also evaluated the potency of biofilm formation. RESULTS: Stool fungal burdens were significantly higher in mice inoculated with the invasive strains than in those infected with the non-invasive strain. Along with intestinal colonization, liver and kidney fungal burdens were also significantly higher in mice inoculated with the invasive strains. In addition, histopathological findings revealed greater dissemination and colonization of the invasive strains. Regarding biofilm-forming capability, the invasive strain of C. auris exhibited a significantly higher capacity of producing biofilms. Moreover, inoculation with the invasive strains resulted in significantly greater loss of body weight than that noted following infection with the non-invasive strain. CONCLUSIONS: Invasive strains showed higher colonization capability and rates of dissemination from gastrointestinal tracts under cortisone acetate immunosuppression than non-invasive strains, although the mortality rates caused by C. auris were lower than those caused by C. albicans.
Subject(s)
Candida/physiology , Candidiasis, Invasive/pathology , Candidiasis/pathology , Gastrointestinal Tract/microbiology , Animals , Biofilms/growth & development , Candida/pathogenicity , Candida albicans/pathogenicity , Candida albicans/physiology , Candida glabrata/pathogenicity , Candida glabrata/physiology , Candidiasis/microbiology , Candidiasis, Invasive/microbiology , Gastrointestinal Tract/pathology , Male , Mice , Mice, Inbred C57BL , VirulenceABSTRACT
Trichosporon species are some of the most common pathogenic yeasts in Asia, and many are resistant to echinocandin antifungal drugs. Effective treatment of fungal infections requires the selection of appropriate antifungals and the accurate identification of the causal organism. However, in histopathological specimens Trichosporon spp. are often misidentified as Candida species due to morphological similarities. In situ hybridization (ISH) is a useful technique for identifying fungal species in formalin-fixed and paraffin-embedded (FFPE) tissue sections. Although many novel probes for ISH are available, the practical use of ISH for identification of fungi remains limited, in part due to the lack of adequate verifications. We conducted a two-center retrospective observational study in which the ISH technique was used to differentiate Trichosporon spp. and C. albicans in FFPE tissue from autopsy specimens. The study included 88 cases with blood stream yeast infection without Cryptococci extracted from 459 autopsy files of cases with proven invasive fungal infection (IFI). Positive signals for the Trichosporon spp. protein nucleic acid (PNA) probe and C. albicans PNA probe were seen for 7 and 35 cases, respectively, whereas the remaining 46 were negative for both. For the Trichosporon spp.- positive specimens, 5/7 were reported as candidiasis in autopsy records. Our results suggested that accurate histological identification of fungal infections remains challenging, but ISH may be a suitable approach to support histological findings. In addition, this retrospective study suggested that trichosporonosis may have high prevalence among cases of bloodstream yeast infections in Japan.
Subject(s)
In Situ Hybridization , Mycoses/microbiology , Oligonucleotide Probes/genetics , Peptide Nucleic Acids , Trichosporonosis/epidemiology , Trichosporonosis/pathology , Adolescent , Adult , Aged , Aged, 80 and over , Autopsy , Child , Child, Preschool , Female , Formaldehyde , Humans , Infant , Infant, Newborn , Japan/epidemiology , Male , Middle Aged , Mycoses/blood , Paraffin Embedding , Prevalence , Retrospective Studies , Young AdultABSTRACT
BACKGROUND AND OBJECTIVES: Identification of yeasts provides helpful information for appropriate administration of anti-fungal treatments; however, few reports from the Vietnam have been published. This study has been performed to find the prevalence of Candida blood stream isolates from patients in two hospitals in Vietnam. MATERIALS AND METHODS: Candida spp. were isolated from blood cultures in two hospitals, Vietnam between May 2013 and May 2015. Participating hospitals were 103 Military Hospital, Ha Noi city (550 beds) and Cho Ray Hospital, Ho Chi Minh city (1800 beds). All the bloodstream isolates were identified to species level by the germ tube test and polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). In addition, unknown isolates were subjected to PCR sequencing. RESULTS: A total of 93 Candida isolates were isolated from blood cultures during the study period. The results of this study showed that C. tropicalis (n = 47, 50.54%) was the most common agent, followed by Candida albicans/dubliniensis (n = 18, 19.35%), C. parapsilosis (n = 16, 17.20%), C. glabrata (n = 6, 6.45%), C. mesorugosa (n = 5, 5.38%) and C. krusei (n = 1, 1.08%), respectively. CONCLUSION: The frequency of the non-albicans Candida species in blood is increasing, especially C. tropicalis. Additional investigations should be made to clarify the epidemiological profile of invasive Candida bloodstream in Vietnam.
ABSTRACT
Histoplasmosis is occasionally encountered in non-endemic countries owing to more frequent international travel and migration, as well as an increase in the number of vulnerable hosts (e.g., patients with cellular immunodeficiencies). However, the diagnosis of endemic mycoses may be challenging because of its rarity and the limited availability of diagnostic tests. We report a case of disseminated histoplasmosis in a human immunodeficiency virus (HIV)-infected Japanese man who had often travelled to histoplasmosis-endemic countries. We also reviewed the reported cases of HIV-associated histoplasmosis in Japan. To the best of our knowledge, this is the ninth case report of co-infection with Histoplasma and HIV in Japan and the second involving a Japanese patient. This case emphasizes the importance of noting the details of not only the present residence of patients, but also their previous residence and travels. If histoplasmosis is suspected, physicians should inform laboratory personnel that fungal cultures should be incubated for 6 weeks, and compliance with biosafety guidelines for handling the specimens should be practiced. Since death occurs in nearly 50% of HIV-associated histoplasmosis cases in Japan, early recognition, timely diagnosis, and appropriate treatment are mandatory.
Subject(s)
HIV Infections/complications , Histoplasma/isolation & purification , Histoplasmosis/diagnosis , Histoplasmosis/pathology , Adult , Humans , Japan , Lung/diagnostic imaging , Lung/pathology , Male , Microbiological Techniques , Middle Aged , Radiography, Thoracic , Skin/pathology , Tomography, X-Ray ComputedABSTRACT
Cryptococcus gattii is a fungal pathogen, endemic in tropical and subtropical regions, the west coast of Canada, and the United States, that causes a potentially fatal infection in otherwise healthy individuals. Because the cryptococcal polysaccharide capsule is a leading virulence factor due to its resistance against innate immunity, the inhibition of capsule formation may be a promising new therapeutic strategy for C. gattii Macrolides have numerous nonantibiotic effects, including immunomodulation of mammalian cells and suppression of bacterial (but not fungal) pathogenicity. Thus, we hypothesized that a macrolide would inhibit cryptococcal capsule formation and improve the host immune response. Coincubation with clarithromycin (CAM) and azithromycin significantly reduced the capsule thickness and the amount of capsular polysaccharide of both C. gattii and C. neoformans CAM-treated C. gattii cells were significantly more susceptible to H2O2 oxidative stress and opsonophagocytic killing by murine neutrophils. In addition, more C. gattii cells were phagocytosed by murine macrophages, resulting in increased production of tumor necrosis factor alpha (TNF-α) by CAM exposure. After CAM exposure, dephosphorylation of Hog1, one of the mitogen-activated protein kinase (MAPK) signaling pathways of Cryptococcus, was observed in Western blot analysis. In addition, CAM exposure significantly reduced the mRNA expression of LAC1 and LAC2 (such mRNA expression is associated with cell wall integrity and melanin production). These results suggest that CAM may aid in inhibiting capsular formation via the MAPK signaling pathway and by suppressing virulent genes; thus, it may be a useful adjunctive agent for treatment of refractory C. gattii infection.
Subject(s)
Macrolides/pharmacology , Animals , Cryptococcus gattii/drug effects , Immunity, Innate/drug effects , Mice , Oxidative Stress/drug effects , RNA, Messenger/metabolism , Tumor Necrosis Factor-alpha/metabolism , VirulenceABSTRACT
We describe a Venezuelan visitor to Japan who was diagnosed with hemophagocytic lymphohistiocytosis (HLH). The patient was also diagnosed with human immunodeficiency virus (HIV) and Epstein-Barr virus infection by the Western blot and polymerase chain reaction (PCR) tests, respectively. The cause of HLH was considered to be these two infections at first; however, the patient did not recover with antiretroviral/anti-herpes virus therapy. Thereafter, diagnosis of disseminated histoplasmosis was confirmed with an antigen detection test, culture, and PCR test of blood, urine, and bone marrow, and the patient improved gradually after the initiation of liposomal amphotericin B. This case highlights the importance of ruling out endemic mycosis as a cause of HLH even if other probable causes exist in patients from endemic areas.
Subject(s)
Epstein-Barr Virus Infections/diagnosis , HIV Infections/diagnosis , Histoplasmosis/diagnosis , Lymphohistiocytosis, Hemophagocytic/diagnosis , Amphotericin B/therapeutic use , Antiviral Agents/therapeutic use , Epstein-Barr Virus Infections/complications , Epstein-Barr Virus Infections/drug therapy , Epstein-Barr Virus Infections/virology , Female , HIV/drug effects , HIV/pathogenicity , HIV/physiology , HIV Infections/complications , HIV Infections/drug therapy , HIV Infections/virology , Herpesvirus 4, Human/drug effects , Herpesvirus 4, Human/pathogenicity , Herpesvirus 4, Human/physiology , Histoplasma/drug effects , Histoplasma/pathogenicity , Histoplasma/physiology , Histoplasmosis/complications , Histoplasmosis/drug therapy , Histoplasmosis/virology , Humans , Japan , Lymphohistiocytosis, Hemophagocytic/complications , Lymphohistiocytosis, Hemophagocytic/drug therapy , Lymphohistiocytosis, Hemophagocytic/virology , Middle Aged , Travel , VenezuelaABSTRACT
The 23-membered-ring macrolide tacrolimus, a commonly used immunosuppressant, also known as FK506, is a broad-spectrum inhibitor and an efflux pump substrate of pleiotropic drug resistance (PDR) ATP-binding cassette (ABC) transporters. Little, however, is known about the molecular mechanism by which FK506 inhibits PDR transporter drug efflux. Thus, to obtain further insights we searched for FK506-resistant mutants of Saccharomyces cerevisiae cells overexpressing either the endogenous multidrug efflux pump Pdr5 or its Candida albicans orthologue, Cdr1. A simple but powerful screen gave 69 FK506-resistant mutants with, between them, 72 mutations in either Pdr5 or Cdr1. Twenty mutations were in just three Pdr5/Cdr1 equivalent amino acid positions, T550/T540 and T552/S542 of extracellular loop 1 (EL1) and A723/A713 of EL3. Sixty of the 72 mutations were either in the ELs or the extracellular halves of individual transmembrane spans (TMSs), while 11 mutations were found near the center of individual TMSs, mostly in predicted TMS-TMS contact points, and only two mutations were in the cytosolic nucleotide-binding domains of Pdr5. We propose that FK506 inhibits Pdr5 and Cdr1 drug efflux by slowing transporter opening and/or substrate release, and that FK506 resistance of Pdr5/Cdr1 drug efflux is achieved by modifying critical intramolecular contact points that, when mutated, enable the cotransport of FK506 with other pump substrates. This may also explain why the 35 Cdr1 mutations that caused FK506 insensitivity of fluconazole efflux differed from the 13 Cdr1 mutations that caused FK506 insensitivity of cycloheximide efflux.
Subject(s)
ATP-Binding Cassette Transporters/genetics , Antifungal Agents/pharmacology , Candida albicans/genetics , Fungal Proteins/genetics , Membrane Transport Proteins/genetics , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae/genetics , Tacrolimus/pharmacology , Biological Transport/drug effects , Biological Transport/genetics , Candida albicans/drug effects , Depsipeptides/pharmacology , Drug Resistance, Fungal/genetics , Saccharomyces cerevisiae/drug effectsABSTRACT
A pan-azole-resistant Aspergillus fumigatus strain with the cyp51A mutations Gly138Ser and Asn248Lys was isolated from a patient receiving long-term voriconazole treatment. PCR fragments containing cyp51A with the mutations were introduced along with the Cas9 protein and single guide RNA into the azole-resistant/susceptible strains. Recombinant strains showed increased susceptibility via the replacement of Ser138 by glycine. Genetic recombination, which has been hampered thus far in clinical isolates, can now be achieved using CRISPR/Cas9 genome editing.
Subject(s)
Antifungal Agents/therapeutic use , Aspergillosis/drug therapy , Aspergillus fumigatus/drug effects , Aspergillus fumigatus/genetics , Cytochrome P-450 Enzyme System/genetics , Drug Resistance, Fungal/genetics , Fungal Proteins/genetics , Gene Editing/methods , Voriconazole/therapeutic use , Aged , Aspergillus fumigatus/isolation & purification , CRISPR-Cas Systems/genetics , Humans , MaleABSTRACT
Limited data are available on micafungin breakthrough fungemia (MBF), fungemia that develops on administration of micafungin, in patients with hematological disorders. We reviewed medical and microbiological records of patients with hematological disorders who developed MBF between January 2008 and June 2015. A total of 39 patients with MBF were identified, and Candida (30 strains) and non-Candida (9 strains) fungal species were recognized as causative strains. Among 35 stored strains, Candida parapsilosis (14 strains), Trichosporon asahii (7 strains), Candida glabrata (5 strains), and other fungal species (9 strains) were identified by sequencing. Neutropenia was identified as an independent predictor of non-Candida fungemia (P = 0.023). T. asahii was the most common causative strain (7/19) during neutropenia. The 14-day crude mortality rate of patients treated with early micafungin change (EMC) to other antifungal agents was lower than that of the patients not treated with EMC (14% versus 43%, P = 0.044). Most of the stored causative Candida strains were susceptible (80%) or showed wild-type susceptibility (72%) to micafungin. The MICs of voriconazole for T. asahii were low (range, 0.015 to 0.12 µg/ml), whereas the MICs of amphotericin B for T. asahii were high (range, 2 to 4 µg/ml). MBF caused by non-Candida fungus should be considered, especially in patients with neutropenia. EMC could improve early mortality. Based on epidemiology and drug susceptibility profiling, empirical voriconazole-containing therapy might be suitable for treating MBF during neutropenia to cover for T. asahii.
Subject(s)
Antifungal Agents/pharmacology , Fungemia/microbiology , Micafungin/pharmacology , Antifungal Agents/therapeutic use , Candida/drug effects , Candida/pathogenicity , Drug Resistance, Fungal/genetics , Echinocandins/pharmacology , Echinocandins/therapeutic use , Fungemia/drug therapy , Humans , Micafungin/therapeutic use , Microbial Sensitivity Tests , Trichosporon/drug effects , Trichosporon/pathogenicity , Voriconazole/pharmacology , Voriconazole/therapeutic useABSTRACT
The efficacy of recombinant interferon γ (rIFN-γ) for cryptococcal meningoencephalitis has been poorly understood. Compared to Cryptococcus gattii, rIFN-γ significantly improved the survival in experimental meningoencephalitis due to Cryptococcus neoformans. The number of phagocytic macrophages and the levels of inflammatory cytokines production for ex vivo co-incubation with C. neoformans were increased after rIFN-γ stimulation but not C. gattii. Intraspecies differences of phagocytosis by the rIFN-γ-activated macrophages might be associated to the severity of cryptococcal infection.
Subject(s)
Interferon-gamma/therapeutic use , Macrophages/drug effects , Meningoencephalitis/drug therapy , Animals , Antifungal Agents/pharmacology , Antifungal Agents/therapeutic use , Cell Line , Colony Count, Microbial , Cryptococcus gattii/drug effects , Cryptococcus gattii/pathogenicity , Cryptococcus neoformans/drug effects , Cryptococcus neoformans/pathogenicity , Disease Models, Animal , Female , Interferon-gamma/pharmacology , Macrophages/cytology , Macrophages/metabolism , Meningoencephalitis/microbiology , Meningoencephalitis/mortality , Meningoencephalitis/pathology , Mice , Mice, Inbred C57BL , Phagocytosis/drug effects , Species Specificity , Survival Rate , VirulenceABSTRACT
Mitophagy, which is the degradation of mitochondria via selective autophagic machinery, is thought to be involved in regulating the mass and function of mitochondria. Methods for detection of mitophagy have been reported for several fungal cells including some budding yeast, methylotrophic yeast, and filamentous fungi. Mitophagy in Saccharomyces cerevisiae is activated under nitrogen-poor conditions; however, the regulatory mechanism of mitophagy in most fungi has not been elucidated. Here we describe methods to monitor mitophagy in the pathogenic yeast Candida glabrata under iron-depleted conditions but not under nitrogen starvation. This observation may provide some clues to elucidate the physiological roles of mitophagy in eukaryotes.