scholarly journals Assessing Resistance to the Echinocandin Antifungal Drug Caspofungin in Candida albicans by Profiling Mutations in FKS1

2006 ◽  
Vol 50 (6) ◽  
pp. 2058-2063 ◽  
Author(s):  
Sergey V. Balashov ◽  
Steven Park ◽  
David S. Perlin
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Molecular Beacon ◽  
Rapid Identification ◽  
Heterozygous Mutation ◽  
Allele Specific ◽  
Double Amino Acid ◽  
Echinocandin Resistance ◽  
Spontaneous Mutants ◽  
The Relationship

ABSTRACT Resistance of clinical isolates of Candida albicans to the echinocandin drug caspofungin is slowly emerging and is linked to mutations in short conserved regions in the FKS1 gene. The most prominent changes occurred at the serine 645 position in Fks1p with substitutions of proline, tyrosine, and phenylalanine. An allele-specific real-time PCR molecular-beacon assay was developed for rapid identification of drug resistance by targeting FKS1 mutations. Mutations altering serine 645 were reliably identified in both heterozygous and homozygous states. The molecular-beacon assay was used to evaluate two large collections of spontaneous mutants from separate strains of C. albicans with resistance (MICs, >16 μg/ml) to caspofungin with the goal of understanding the relationship between FKS1 mutations and echinocandin resistance. Of 85 resistant isolates recovered, all were identified with mutations in FKS1; 93% showed changes at Ser645, with 62% displaying a characteristic S645P substitution expressed as either a homozygous or a heterozygous mutation in FKS1. Two other prominent amino acid substitutions, S645Y and S645F, were found at frequencies of 22% and 8%, respectively. Three new mutations were also identified: T1922C, G1932T, and C1934G, encoding F641S, L644F, and S645C substitutions, respectively. One strain had the double amino acid substitution L644F and S645C. Allele-specific probes were combined in a multiplex assay for reliable screening of known FKS1 mutations. These data support the importance of FKS1p substitutions in echinocandin resistance and demonstrate the feasibility of applying molecular screening for routine resistance assessment.

scholarly journals Rapid Detection ofFKS-Associated Echinocandin Resistance in Candida glabrata

2016 ◽  
Vol 60 (11) ◽  
pp. 6573-6577 ◽  
Author(s):  
Yanan Zhao ◽  
Yoji Nagasaki ◽  
Milena Kordalewska ◽  
Ellen G. Press ◽  
Ryan K. Shields ◽  
...  
Keyword(s):  
Candida Glabrata ◽  
Molecular Beacon ◽  
Rapid Identification ◽  
Molecular Diagnostic ◽  
Wild Type ◽  
Asymmetric Pcr ◽  
Content Type ◽  
Allele Specific ◽  
Echinocandin Resistance

ABSTRACTA novel and highly accurate diagnostic assay platform was established for rapid identification ofFKSmutations associated with echinocandin resistance inCandida glabrata. The assay platform uses allele-specific molecular beacon and DNA melt analysis following asymmetric PCR. A dual assay forFKS1andFKS2was developed to identify within 3 h the most common and clinically relevant resistance-associated mutations, including 8FKS1HS1 (wild type [WT], S629P, F625S, D632Y, D632E [T1896G], D632E [T1896A], I634V, and F625F) and 7FKS2HS1 (WT, F659del, F659S, F659V, F659L, S663P, and S663F) genotypes. A blinded panel of 188C. glabrataclinical isolates was tested by both assays. The molecular diagnostic results from the dual assay were 100% concordant with data obtained from DNA sequencing. This platform has the potential to overcome the deficiencies of existingin vitrosusceptibility-based assays to identify echinocandin-resistantC. glabrataand holds promise as a surrogate diagnostic method to better direct echinocandin therapy.

scholarly journals Correlation between Azole Susceptibilities, Genotypes, and ERG11 Mutations in Candida albicans Isolates Associated with Vulvovaginal Candidiasis in China

2010 ◽  
Vol 54 (8) ◽  
pp. 3126-3131 ◽  
Author(s):  
Shu-Hua Ge ◽  
Zhe Wan ◽  
Juan Li ◽  
Jianping Xu ◽  
Ruo-Yu Li ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Amino Acid ◽  
Oral Cavity ◽  
Target Gene ◽  
Chinese Women ◽  
Missense Mutations ◽  
Statistical Support ◽  
Strain Sc5314 ◽  
The Relationship ◽  
Susceptibility Patterns

ABSTRACT The relationship between susceptibilities to fluconazole and itraconazole and microsatellite CAI genotypes were examined from a total of 154 Candida albicans isolates (97 isolates causing vulvovaginitis in Chinese women and 6 vaginal isolates and 51 oral cavity isolates from asymptomatic carriers). The two dominant genotypes, CAI 30-45 (45 isolates) and CAI 32-46 (33 isolates), associated with vulvovaginitis showed significantly different azole susceptibility patterns with strong statistical support. CAI 32-46 isolates were usually less susceptible to both fluconazole and itraconazole than CAI 30-45 isolates and than the oral isolates with other diversified CAI genotypes. Remarkably different mutation patterns in the azole target gene ERG11 were correspondingly observed among C. albicans isolates representing different genotypes and sources. Isolates with the same or similar CAI genotypes usually possessed identical or phylogenetically closely related ERG11 sequences. Loss of heterozygosity in ERG11 was observed in all the CAI 32-46 isolates but not in the CAI 30-45 isolates and most of the oral isolates sequenced. Compared with the ERG11 sequence of strain SC5314 (X13296), two homozygous missense mutations (G487T and T916C) leading to two amino acid changes (A114S and Y257H) in Erg11p were found in CAI 32-46 isolates. The correlation between azole susceptibility and C. albicans genotype may be of potential therapeutic significance.

scholarly journals Large-scale genome mining allows identification of neutral polymorphisms and novel resistance mutations in genes involved in Candida albicans resistance to azoles and echinocandins

2020 ◽  
Vol 75 (4) ◽  
pp. 835-848 ◽  
Author(s):  
Emilie Sitterlé ◽  
Alix T Coste ◽  
Thomas Obadia ◽  
Corinne Maufrais ◽  
Murielle Chauvel ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Large Scale ◽  
Genome Mining ◽  
Point Mutations ◽  
Rapid Identification ◽  
Antifungal Drugs ◽  
Resistance Mutations ◽  
Phenotypic Resistance ◽  
Echinocandin Resistance ◽  
Resistant Strains

Abstract Background The genome of Candida albicans displays significant polymorphism. Point mutations in genes involved in resistance to antifungals may either confer phenotypic resistance or be devoid of phenotypic consequences. Objectives To catalogue polymorphisms in azole and echinocandin resistance genes occurring in susceptible strains in order to rapidly pinpoint relevant mutations in resistant strains. Methods Genome sequences from 151 unrelated C. albicans strains susceptible to fluconazole and caspofungin were used to create a catalogue of non-synonymous polymorphisms in genes involved in resistance to azoles (ERG11, TAC1, MRR1 and UPC2) or echinocandins (FKS1). The potential of this catalogue to reveal putative resistance mutations was tested in 10 azole-resistant isolates, including 1 intermediate to caspofungin. Selected mutations were analysed by mutagenesis experiments or mutational prediction effect. Results In the susceptible strains, we identified 126 amino acid substitutions constituting the catalogue of phenotypically neutral polymorphisms. By excluding these neutral substitutions, we identified 22 additional substitutions in the 10 resistant strains. Among these substitutions, 10 had already been associated with resistance. The remaining 12 were in Tac1p (n = 6), Upc2p (n = 2) and Erg11p (n = 4). Four out of the six homozygous substitutions in Tac1p (H263Y, A790V, H839Y and P971S) conferred increases in azole MICs, while no effects were observed for those in Upc2p. Additionally, two homozygous substitutions (Y64H and P236S) had a predicted conformation effect on Erg11p. Conclusions By establishing a catalogue of neutral polymorphisms occurring in genes involved in resistance to antifungal drugs, we provide a useful resource for rapid identification of mutations possibly responsible for phenotypic resistance in C. albicans.

scholarly journals Overdiagnosis and overtreatment of nipple and breast candidiasis: A review of the relationship between diagnoses of mammary candidiasis and Candida albicans in breastfeeding women

2021 ◽  
Vol 17 ◽  
pp. 174550652110314
Author(s):  
Pamela Douglas
Keyword(s):  
Candida Albicans ◽  
Human Milk ◽  
Signs And Symptoms ◽  
Breast Pain ◽  
Breastfeeding Support ◽  
Candida Spp ◽  
Healthy Human ◽  
Nipple Areolar Complex ◽  
Areolar Complex ◽  
The Relationship

Background: Breastfeeding mothers commonly experience nipple pain accompanied by radiating, stabbing or constant breast pain between feeds, sometimes associated with pink shiny nipple epithelium and white flakes of skin. Current guidelines diagnose these signs and symptoms as mammary candidiasis and stipulate antifungal medications. Aim: This study reviews existing research into the relationship between Candida albicans and nipple and breast pain in breastfeeding women who have been diagnosed with mammary candidiasis; whether fluconazole is an effective treatment; and the presence of C. albicans in the human milk microbiome. Method: The author conducted three searches to investigate (a) breastfeeding-related pain and C. albicans; (b) the efficacy of fluconazole in breastfeeding-related pain; and (c) composition of the human milk mycobiome. These findings are critiqued and integrated in a narrative review. Results: There is little evidence to support the hypothesis that Candida spp, including C. albicans, in maternal milk or on the nipple-areolar complex causes the signs and symptoms popularly diagnosed as mammary candidiasis. There is no evidence that antifungal treatments are any more effective than the passage of time in women with these symptoms. Candida spp including C. albicans are commonly identified in healthy human milk and nipple-areolar complex mycobiomes. Discussion: Clinical breastfeeding support remains a research frontier. The human milk microbiome, which includes a mycobiome, interacts with the microbiomes of the infant mouth and nipple-areolar complex, including their mycobiomes, to form protective ecosystems. Topical or oral antifungals may disrupt immunoprotective microbial homeostasis. Unnecessary use contributes to the serious global problem of antifungal resistance. Conclusion: Antifungal treatment is rarely indicated and prolonged courses cannot be justified in breastfeeding women experiencing breast and nipple pain. Multiple strategies for stabilizing microbiome feedback loops when nipple and breast pain emerge are required, in order to avoid overtreatment of breastfeeding mothers and their infants with antifungal medications.

scholarly journals Two User-Friendly Molecular Markers Developed for the Identification of Hybrid Lethality Genes in Brassica oleracea

Agronomy ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 982
Author(s):  
Zhiliang Xiao ◽  
Congcong Kong ◽  
Fengqing Han ◽  
Limei Yang ◽  
Mu Zhuang ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Brassica Oleracea ◽  
Rapid Identification ◽  
Inbred Lines ◽  
Hybrid Lethality ◽  
Specific Pcr ◽  
Allele Specific ◽  
User Friendly ◽  
Allele Specific Pcr ◽  
Kasp Marker

Cabbage (Brassica oleracea) is an important vegetable crop that is cultivated worldwide. Previously, we reported the identification of two dominant complementary hybrid lethality (HL) genes in cabbage that could result in the death of hybrids. To avoid such losses in the breeding process, we attempted to develop molecular markers to identify HL lines. Among 54 previous mapping markers closely linked to BoHL1 or BoHL2, only six markers for BoHL2 were available in eight cabbage lines (two BoHL1 lines; three BoHL2 lines; three lines without BoHL); however, they were neither universal nor user-friendly in more inbred lines. To develop more accurate markers, these cabbage lines were resequenced at an ~20× depth to obtain more nucleotide variations in the mapping regions. Then, an InDel in BoHL1 and a single-nucleotide polymorphism (SNP) in BoHL2 were identified, and the corresponding InDel marker MBoHL1 and the competitive allele-specific PCR (KASP) marker KBoHL2 were developed and showed 100% accuracy in eight inbred lines. Moreover, we identified 138 cabbage lines using the two markers, among which one inbred line carried BoHL1 and 11 inbred lines carried BoHL2. All of the lethal line genotypes obtained with the two markers matched the phenotype. Two markers were highly reliable for the rapid identification of HL genes in cabbage.

Candida albicans Shunt Infection: Report of Two Cases

Neurosurgery ◽  
1986 ◽  
Vol 19 (1) ◽  
pp. 111-113 ◽  
Author(s):  
David J. Gower ◽  
Kerry Crone ◽  
Eben Alexander ◽  
David L. Kelly
Keyword(s):  
Candida Albicans ◽  
Blood Cells ◽  
White Blood Cells ◽  
Shunt Infection ◽  
Cerebrospinal Fluid Shunts ◽  
Previous Therapy ◽  
Relationship Of ◽  
The Relationship ◽  
Overall Mortality

Abstract Infection of cerebrospinal fluid shunts with Candida albicans is reported in two patients. Scanning electron microscopy in one case demonstrates the relationship of the Candida hyphae to the white blood cells and to silicone plastic. A review of 10 previously reported cases of Candida shunt infection indicates that the infection usually follows a major bacterial infection or direct contamination or occurs spontaneously, Previous therapy has usually involved removal of the shunt, and the role of parenteral antifungal therapy is still unclear. Overall mortality to date is 25%.

Cationic Amino Acid Transporter-1 (CAT-1) Promotes Fibroblast-Like Synoviocytes Proliferation and Cytokine Secretion by Taking Up L-Arginine in Rheumatoid Arthritis

2021 ◽  
Author(s):  
Ying Lu ◽  
Chongbo Hao ◽  
Shanshan Yu ◽  
Zuan Ma ◽  
Xuelian Fu ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
Amino Acid ◽  
Synovial Fluid ◽  
Culture Conditions ◽  
Cytokine Secretion ◽  
Cationic Amino Acid Transporter ◽  
Cationic Amino Acid ◽  
The Relationship ◽  
Fibroblast Like Synoviocytes

Abstract Background: Abnormal proliferation of fibroblast-like synoviocytes (FLSs) in the synovial lining layer is the primary cause of synovial hyperplasia and joint destruction in rheumatoid arthritis (RA). Currently, the relationship between metabolic abnormalities and FLS proliferation is a new focus of investigation. However, little is known regarding the relationship between amino acid metabolism and RA. Methods: The concentrations of amino acids and cytokines in the synovial fluid of RA (n=9) and osteoarthritis (OA,n=9) were detected by LC-MS/MS and CBA assay, respectively. The mRNA and protein expression of CAT-1 were determined in FLSs isolated from RA and OA patients by real-time PCR and western blotting. MTT assay, cell cycle, apoptosis, invasion and cytokine secretion were determined in FLSs knocked down of CAT-1 using siRNA or treated with D-arginine under normoxic and hypoxic culture conditions. A mouse collagen-induced arthritis (CIA) model was applied to test the therapeutic potential of blocking the uptake of L-arginine in vivo.Results: L-arginine was upregulated in the synovial fluid of RA patients and was positively correlated with elevation of the cytokines IL-1β, IL-6 and IL-8. Further examination demonstrated that cationic amino acid transporter-1 (CAT-1) was the primary transporter for L-arginine and was overexpressed on RA FLSs compared to OA FLSs. Moreover, knockdown of CAT-1 using siRNA or inhibition of L-arginine uptake using D-arginine significantly suppressed L-arginine metabolism, cell proliferation, migration and cytokine secretion in RA FLSs under normoxic and hypoxic culture conditions in vitro but increased cell apoptosis in a dose-dependent manner. Meanwhile, in vivo assays revealed that an L-arginine-free diet or blocking the uptake of L-arginine using D-arginine suppressed arthritis progression in CIA mice. Conclusion: CAT-1 is upregulated and promotes FLS proliferation by taking up L-arginine, thereby promoting RA progression.

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