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Journal of Clinical Microbiology Feb 1978Cryptococcus neoformans and other Cryptococcus species can produce pigment(s) from many aminophenol and diaminobenzene compounds. Pigment production from these compounds... (Comparative Study)
Comparative Study
Cryptococcus neoformans and other Cryptococcus species can produce pigment(s) from many aminophenol and diaminobenzene compounds. Pigment production from these compounds is similar to the conversion of diphenols to melanin by C. neoformans. Several pigmentation patterns (resulting in the identification or grouping of Cryptococcus species) have been observed by using diaminobenzene and aminophenol compounds as substrates. The most common pigmentation pattern observed was pigment production by both C. neoformans and C. terreus. In contrast to the diphenols, only two aminophenols (4-hydroxymetanilamide and 3-aminotyrosine) were found to be highly specific as substrates. They allowed only C. neoformans to produce pigment. When 4-aminosalicylic acid was the substrate, a unique pattern was observed because only C. terreus, C. diffluens, and C. albidus produced pigment. Finally, a pattern was observed in which C. neoformans produced large amounts of pigment from aminophenol and diaminobenzene compounds, whereas the other Cryptococcus species produced smaller amounts. A simplified scheme with three substrates resulted in the identification of C. terreus and C. neoformans as well as two groups of other Cryptococcus species, group I (C. albidus and C. diffluens) and group II (C. laurentii and C. luteolus).
Topics: Aminobenzoates; Aminosalicylic Acids; Aniline Compounds; Cryptococcus; Cryptococcus neoformans; Pigments, Biological; Species Specificity
PubMed: 344335
DOI: 10.1128/jcm.7.2.146-152.1978 -
The Canadian Journal of Infectious... 2020Cryptococcosis, a life-threatening mycosis caused mainly by , appears to be distinctly rare in hematopoietic stem cell transplant (HSCT) recipients. When it occurs, this... (Review)
Review
Cryptococcosis, a life-threatening mycosis caused mainly by , appears to be distinctly rare in hematopoietic stem cell transplant (HSCT) recipients. When it occurs, this fungal infection is a major limitation for a successful transplant. This review comprehensively analyses 24 cases, reported in the literature, of patients with haematological malignancies including leukemias, multiple myeloma, and lymphomas, as indication for HSCT, who presented with cryptococcosis after transplantation. Of the 24 cases, 11 each occurred in patients receiving allogeneic and autologous stem cell transplants, from bone marrow, peripheral blood, and umbilical cord blood. HSCT recipients were slightly more often male, and the age of the patients ranged from 12 to 74 years. Antifungal prophylaxis was reported in most cases. Clinical manifestations of cryptococcal disease included more frequently central nervous system involvement followed by fungaemia, disseminated infection, pulmonary cryptococcosis, cerebellitis, and diarrhea. Diagnosis differed depending on the clinical presentation but habitually included cryptococcal antigen assay, India ink, and culture. Notably, not only but also , , , and were identified as the causal species, the last two including strains resistant to fluconazole. Amphotericin B, alone or in combination, was the most common antifungal drug used for the treatment of cryptococcosis in HSCT recipients. Due to the small number of cases, it was not possible to establish if mortality rate, which was the same as survival rate, depends on the effect of the immunosuppressive regimen, the site of cryptococcal infection, and/or the antifungal therapy used to control the mycosis. Although uncommon, the recognition of cryptococcal disease in stem cell transplant is essential for a timely and adequate treatment, improved prognosis, reduced morbidity and mortality, and successful transplantation.
PubMed: 33144899
DOI: 10.1155/2020/3713241 -
PeerJ 2022Antimicrobial compounds, including antibiotics, have been a cornerstone of modern medicine being able to both treat infections and prevent infections in at-risk people,...
Antimicrobial compounds, including antibiotics, have been a cornerstone of modern medicine being able to both treat infections and prevent infections in at-risk people, including those who are immune-compromised and those undergoing routine surgical procedures. Their intense use, including in people, animals, and plants, has led to an increase in the incidence of resistant bacteria and fungi, resulting in a desperate need for novel antimicrobial compounds with new mechanisms of action. Many antimicrobial compounds in current use originate from microbial sources, such as penicillin from the fungus (renamed by some as ). Through a collaboration with Aotearoa New Zealand Crown Research Institute Manaaki Whenua-Landcare Research we have access to a collection of thousands of fungal cultures known as the International Collection of Microorganisms from Plants (ICMP). The ICMP contains both known and novel species which have not been extensively tested for their antimicrobial activity. Initial screening of ICMP isolates for activity against and directed our interest towards ICMP 477, an isolate of the soil-inhabiting fungus, . In our investigation of the secondary metabolites of , through extraction, fractionation, and purification, we isolated nine known natural products. We evaluated the biological activity of selected compounds against various bacteria and fungi and discovered that terrein () has potent activity against the important human pathogen .
Topics: Animals; Humans; Cryptococcus neoformans; Anti-Infective Agents; Aspergillus; Anti-Bacterial Agents; Bacteria
PubMed: 36275475
DOI: 10.7717/peerj.14239 -
The European Respiratory Journal Jul 2018Understanding the composition and clinical importance of the fungal mycobiome was recently identified as a key topic in a "research priorities" consensus statement for...
Understanding the composition and clinical importance of the fungal mycobiome was recently identified as a key topic in a "research priorities" consensus statement for bronchiectasis.Patients were recruited as part of the CAMEB study: an international multicentre cross-sectional Cohort of Asian and Matched European Bronchiectasis patients. The mycobiome was determined in 238 patients by targeted amplicon shotgun sequencing of the 18S-28S rRNA internally transcribed spacer regions ITS1 and ITS2. Specific quantitative PCR for detection of and conidial quantification for a range of airway species was performed. Sputum galactomannan, specific IgE, IgG and TARC (thymus and activation regulated chemokine) levels were measured systemically and associated to clinical outcomes.The bronchiectasis mycobiome is distinct and characterised by specific fungal genera, including , and (in Singapore/Kuala Lumpur) and (in Dundee) dominated profiles, the latter associating with exacerbations. High frequencies of associated disease including sensitisation and allergic bronchopulmonary aspergillosis were detected. Each revealed distinct mycobiome profiles, and associated with more severe disease, poorer pulmonary function and increased exacerbations.The pulmonary mycobiome is of clinical relevance in bronchiectasis. Screening for -associated disease should be considered even in apparently stable patients.
Topics: Adult; Aged; Antibodies, Fungal; Aspergillus; Bronchiectasis; Cohort Studies; Cross-Sectional Studies; Disease Progression; Female; Fungi; Humans; Immunoglobulin Isotypes; Malaysia; Male; Middle Aged; Mycobiome; Pulmonary Aspergillosis; Singapore; Sputum; United Kingdom
PubMed: 29880655
DOI: 10.1183/13993003.00766-2018 -
BMC Infectious Diseases Oct 2022Pulmonary tuberculosis (PTB) is a significant risk factor for fungal infection. The cavitary lesions post PTB serves as a good reservoir for fungal colonization and...
BACKGROUND
Pulmonary tuberculosis (PTB) is a significant risk factor for fungal infection. The cavitary lesions post PTB serves as a good reservoir for fungal colonization and subsequent infection. Furthermore, the severe immunosuppression associated with HIV and TB co-infection is another predisposition. The inadequate capacity to investigate and manage fungal infection in PTB patients increases their morbidity and mortality. The study aimed to provide serological evidence of chronic pulmonary aspergillosis (CPA) among PTB patients in Kenya. Towards this, we analysed 234 serum samples from patients presenting with persistent clinical features of PTB infections despite TB treatment in four referral hospitals.
METHODS
This was a cross sectional laboratory based study and patients were recruited following an informed consent. Serological detection of Aspergillus fumigatus IgG was done using enzyme-linked immunosorbent assay (Bordier Affinity Products SA). Sputum samples were subjected to microscopy and standard fungal culture. The isolated fungi were subjected to macro and micro morphological identifications and confirmed by sequence analysis of calmadulin, betatubilin and ITS genes.
RESULTS
Serological evidence of CPA or fungal sensitization was 46(19.7%) and equivocal or borderline was 14(6.0%). Mycological investigations of sputum resulted in 88(38%) positive for fungal culture. Aspergillus spp. accounted for 25(28%) of which A. fumigatus was 13(14.8%), A. niger 8(9.1%), A. terreus, A. flavus, A. candidus and A. clavatus 1 (1.1%) each. This was followed by Penicillium spp. 10 (11.4%), Scedosporium spp. 5 (5.7%) and Rhizopus spp. 3 (3.4%). Among the yeasts; Candida albicans accounted for 18(20.5%) followed by C. glabrata 5(5.7%). Cryptococcus spp. was isolated from 3(3.4%) of the samples while 13(14.8%) were other yeasts.
CONCLUSION
Chronic pulmonary aspergillosis is a significant co-morbidity in PTB patients in Kenya that could be misdiagnosed as relapse or treatment failures in the absence of reliable diagnostic and clinical management algorithm. It could be the cause of persistent clinical symptoms despite TB treatment often misdiagnosed as TB smear/GeneXpert MTB/RIF® negative or relapse. We recommend that all patients with persistent clinical symptoms despite TB treatment should be subjected to fungal investigations before retreatment.
Topics: Humans; Cross-Sectional Studies; Kenya; Tuberculosis, Pulmonary; Sputum; Tuberculosis; Pulmonary Aspergillosis; Mycoses; Chronic Disease; Immunoglobulin G; Recurrence; Mycobacterium tuberculosis
PubMed: 36284285
DOI: 10.1186/s12879-022-07782-9 -
RSC Advances Jul 2021Microbial infections are considered one of the most dangerous infections in humans due to their resistance to most antimicrobial agents. In this study, nanocomposites...
Microbial infections are considered one of the most dangerous infections in humans due to their resistance to most antimicrobial agents. In this study, nanocomposites based on reduced graphene oxide (RGO) and metal oxides (NiO, AgO, and ZnO) were fabricated. The graphite precursor and RGO were characterized by XRD, Raman spectroscopy, SEM, and HRTEM, while SEM, XRD, and EDX mapping analysis validated the synthesized nanocomposites. In addition, ZOI and MIC were employed to test the antimicrobial potential, while their antibiofilm activity and the effect of UV illumination were also investigated. Finally, reaction mechanism determination was performed using SEM analysis. The results revealed that all the synthesized nanocomposites (RGO-NiO, RGO-AgO, and RGO-ZnO) had outstanding antimicrobial activity against Gram-negative bacteria ( and ), Gram-positive bacteria ( and ), unicellular fungi ( and ) and multicellular fungi (, , and ). Moreover, the synthesized RGO-NiO nanocomposite exhibited antibiofilm activity (following 10.0 µg mL RGO-NiO), with an inhibition percentage of 94.60% for , 91.74% for , and 98.03% for . The maximum percentage inhibition under UV illumination toward , and at the end of the experiment using RGO-NiO were 83.21%, 88.54%, and 91.15%, respectively, while the values of RGO-AgO were 64.85%, 68.0%, and 80.15%, respectively, and those of RGO-ZnO were 72.95%, 82.15%, and 79.25%, respectively. The SEM analysis of in the absence of the RGO-NiO nanocomposite showed the development of unicellular fungal cells by regular budding. In contrast, after RGO-NiO treatment, noticeable morphological differences were identified in , including the lysis of the outer surface with deformations of the fungal cells. In conclusion, the prepared nanocomposites are promising antimicrobial and antibiofilm agents and can be used to treat the pathogenic microbes at low concentrations and represent a new strategy for managing infectious diseases caused by pathogenic microorganisms.
PubMed: 35479482
DOI: 10.1039/d1ra04542c -
Medicine Feb 2020The incidence of invasive fungal infections (IFIs) has recently increased, and early and accurate diagnosis of IFIs is important for the rational selection of antifungal...
The incidence of invasive fungal infections (IFIs) has recently increased, and early and accurate diagnosis of IFIs is important for the rational selection of antifungal drugs with high efficacy. We developed a method for rapid and accurate clinical diagnosis of IFIs and provide a reference for personalized drug treatment.We designed and screened fungal internal transcribed spacer regions with universal primers and designed 8 TaqMan detection probes to establish a multi-channel real-time fluorescent polymerase chain reaction (PCR) melting curve analysis (MCA) method. The sensitivity, specificity, and reproducibility of this method were investigated using standard fungal strains and clinical isolates. Candidemia was detected using the MCA method.The limit of detection and assay cut-off (melting temperature [Tm]) for Candida albicans were 0.05 pg/μL and 66.50 °C; Candida glabrata were 0.1 pg/μL and 66.25 °C; Candida tropicalis were 0.1 pg/μL and 60.15 °C; Candida krusei were 0.1 pg/μL and 72.15 °C; Candida parapsilosis were 0.2 pg/μL and 63.10 °C; Candida guilliermondii were 0.1 pg/μL and 61.84 °C; Cryptococcus neoformans were 0.1 pg/μL and 65.50 °C; Aspergillus flavus were 0.05 pg/μL and 71.50 °C; Aspergillus terreus, Aspergillus fumigatus, and Aspergillus niger were 0.05 pg/μL and 76.80 °C. Analytical specificity was evaluated using 13 clinical pathogens including Streptococcus pneumoniae, Staphylococcus aureus, and Haemophilus influenzae, etc. No false-positive results were obtained for any of these samples. The MCA method can detect and identify different candidemia simulations. The limit detection concentration of C albicans was 44 cfu/mL, C glabrata was 73 cfu/mL, C tropicalis was 29 cfu/mL, C parapsilosis was 21 cfu/mL, C krusei was 71 cfu/mL, and C guilliermondii was 53 cfu/mL.The multi-channel real-time fluorescence PCR melting curve analysis displayed high sensitivity and specificity in detecting various clinically invasive fungi. Furthermore, it simultaneously detected the genera Candida, Cryptococcus, and Aspergillus and identified Candida at the species level. Our method can facilitate early and accurate clinical diagnosis and personalized medication regimens.
Topics: Aspergillus; Candida; Cryptococcus; Fluorescent Dyes; Humans; Invasive Fungal Infections; Quality Improvement; Real-Time Polymerase Chain Reaction
PubMed: 32049856
DOI: 10.1097/MD.0000000000019194 -
Antimicrobial Agents and Chemotherapy Oct 2018Monitoring antifungal susceptibility patterns for new and established antifungal agents seems prudent given the increasing prevalence of uncommon species associated with...
Monitoring antifungal susceptibility patterns for new and established antifungal agents seems prudent given the increasing prevalence of uncommon species associated with higher antifungal resistance. We evaluated the activity of isavuconazole against 4,856 invasive yeasts and molds collected worldwide. The 4,856 clinical fungal isolates, including 2,351 species isolates, 97 non- yeasts, 1,972 species isolates, and 361 non- molds, including 292 isolates collected in 2015 to 2016, were tested using CLSI methods. The MIC values for isavuconazole versus ranged from 0.06 to ≥16 μg/ml. The modal MIC for isavuconazole was 0.5 μg/ml (range, 0.25 [ and species complex] to 4 μg/ml [ and ]). Eight isolates had elevated isavuconazole MIC values at ≥8 μg/ml (non-wild type). Isavuconazole showed comparable activity to itraconazole against the The lowest modal isavuconazole MIC values were seen for spp., var. , and (all 1 μg/ml). species isolates were inhibited by ≤0.25 μg/ml of isavuconazole (range, 96.1% [] to 100.0% [, , , and ]). MIC values were ≤1 μg/ml for 95.5% of isolates and 100.0% of isolates. Isavuconazole was active against the non- yeasts, including (100.0% at ≤0.5 μg/ml). Isavuconazole exhibited excellent activity against most species of and Isavuconazole was comparable to posaconazole and voriconazole against the less common yeasts and molds. Isavuconazole was generally less active than posaconazole and more active than voriconazole against the 292 isolates. We confirm the potentially useful activity of isavuconazole against species of as determined by CLSI methods.
Topics: Antifungal Agents; Aspergillus; Drug Resistance, Fungal; Microbial Sensitivity Tests; Mucorales; Nitriles; Proteomics; Pyridines; Saccharomyces cerevisiae; Triazoles; Voriconazole
PubMed: 30061288
DOI: 10.1128/AAC.01230-18 -
Virulence Jan 2020Members of the species complex stand out by unique virulence factors that allowed evolutionary transition to pathogenesis. Among the factors contributing to...
Members of the species complex stand out by unique virulence factors that allowed evolutionary transition to pathogenesis. Among the factors contributing to cryptococcosis is a morphological transformation into giant (Titan) cells. It remains unclear whether species outside of the / species complex are capable of titanization. We utilized two recently developed protocols that allow obtaining Titan cells to test if titanization occurs in non-/ species. We find that none of the tested strains, representing 10 species of basidiomycetous yeasts and the ascomycetous yeast , undergo significant titanization under conditions that promote robust Titan cell formation in / species complex. formed occasional enlarged cells through a mechanism potentially similar to that of titanization. Our findings suggest that titanization is a rare phenomenon among basidiomycetous yeasts that occurs mostly in members of the species complex.
Topics: Cryptococcus; Cryptococcus gattii; Cryptococcus neoformans; Virulence
PubMed: 32498590
DOI: 10.1080/21505594.2020.1772657 -
Applied and Environmental Microbiology Jun 1976Of 38 pure cultures of microorganisms tested, only one, Pseudomonas stutzeri, was capable of forming dimethylnitrosamine from dimethylamine and nitrite during growth....
Of 38 pure cultures of microorganisms tested, only one, Pseudomonas stutzeri, was capable of forming dimethylnitrosamine from dimethylamine and nitrite during growth. Resting cells of P. stutzeri, Cryptococcus terreus, Escherichia coli, and Xanthomonas campestris formed dimethylnitrosamine, although no nitrosamine was found in growing cultures of the latter three organisms. No nitrosamine was produced by either growing cultures or resting-cell suspensions of Pseudomonas fragi or Proteus mirabilis. Boiled cells of P. stutzeri, but not those of C. terreus, E. coli, and X. campestris, formed dimethylnitrosamine, and this nitrosamine was also produced by extracts of E. coli cells at pH 5.0.
Topics: Bacteria; Cryptococcus; Dimethylamines; Dimethylnitrosamine; Escherichia coli; Fungi; Hydrogen-Ion Concentration; Nitrites; Nitrosamines; Proteus; Pseudomonas; Species Specificity; Xanthomonas
PubMed: 7197
DOI: 10.1128/aem.31.6.892-895.1976