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Cells Nov 2023Candidiasis is a highly pervasive infection posing major health risks, especially for immunocompromised populations. Pathogenic species have evolved intrinsic and... (Review)
Review
Candidiasis is a highly pervasive infection posing major health risks, especially for immunocompromised populations. Pathogenic species have evolved intrinsic and acquired resistance to a variety of antifungal medications. The primary goal of this literature review is to summarize the molecular mechanisms associated with antifungal resistance in species. Resistance can be conferred via gain-of-function mutations in target pathway genes or their transcriptional regulators. Therefore, an overview of the known gene mutations is presented for the following antifungals: azoles (fluconazole, voriconazole, posaconazole and itraconazole), echinocandins (caspofungin, anidulafungin and micafungin), polyenes (amphotericin B and nystatin) and 5-fluorocytosine (5-FC). The following mutation hot spots were identified: (1) ergosterol biosynthesis pathway mutations (ERG11 and UPC2), resulting in azole resistance; (2) overexpression of the efflux pumps, promoting azole resistance (transcription factor genes: and ; transporter genes: CDR1, CDR2, MDR1, PDR16 and SNQ2); (3) cell wall biosynthesis mutations (FKS1, FKS2 and PDR1), conferring resistance to echinocandins; (4) mutations of nucleic acid synthesis/repair genes (FCY1, FCY2 and FUR1), resulting in 5-FC resistance; and (5) biofilm production, promoting general antifungal resistance. This review also provides a summary of standardized inhibitory breakpoints obtained from international guidelines for prominent species. Notably, , and demonstrate fluconazole resistance.
Topics: Antifungal Agents; Candida; Fluconazole; Echinocandins; Azoles
PubMed: 37998390
DOI: 10.3390/cells12222655 -
The Journal of Infection Nov 2023The objectives of this study were to assess Candida spp. distribution and antifungal resistance of candidaemia across Europe. Isolates were collected as part of the...
The objectives of this study were to assess Candida spp. distribution and antifungal resistance of candidaemia across Europe. Isolates were collected as part of the third ECMM Candida European multicentre observational study, conducted from 01 to 07-07-2018 to 31-03-2022. Each centre (maximum number/country determined by population size) included ∼10 consecutive cases. Isolates were referred to central laboratories and identified by morphology and MALDI-TOF, supplemented by ITS-sequencing when needed. EUCAST MICs were determined for five antifungals. fks sequencing was performed for echinocandin resistant isolates. The 399 isolates from 41 centres in 17 countries included C. albicans (47.1%), C. glabrata (22.3%), C. parapsilosis (15.0%), C. tropicalis (6.3%), C. dubliniensis and C. krusei (2.3% each) and other species (4.8%). Austria had the highest C. albicans proportion (77%), Czech Republic, France and UK the highest C. glabrata proportions (25-33%) while Italy and Turkey had the highest C. parapsilosis proportions (24-26%). All isolates were amphotericin B susceptible. Fluconazole resistance was found in 4% C. tropicalis, 12% C. glabrata (from six countries across Europe), 17% C. parapsilosis (from Greece, Italy, and Turkey) and 20% other Candida spp. Four isolates were anidulafungin and micafungin resistant/non-wild-type and five resistant to micafungin only. Three/3 and 2/5 of these were sequenced and harboured fks-alterations including a novel L657W in C. parapsilosis. The epidemiology varied among centres and countries. Acquired echinocandin resistance was rare but included differential susceptibility to anidulafungin and micafungin, and resistant C. parapsilosis. Fluconazole and voriconazole cross-resistance was common in C. glabrata and C. parapsilosis but with different geographical prevalence.
PubMed: 37549695
DOI: 10.1016/j.jinf.2023.08.001 -
Microbial Genomics Jul 2023Invasive candida infections are significant infections that may occur in vulnerable patients with high rates of mortality or morbidity. Drug-resistance rates also appear...
Invasive candida infections are significant infections that may occur in vulnerable patients with high rates of mortality or morbidity. Drug-resistance rates also appear to be on the rise which further complicate treatment options and outcomes. The aims of this study were to describe the prevalence, molecular epidemiology, and genetic features of bloodstream isolates in a hospital setting. The resistance mechanisms towards the two most commonly administered antifungals, fluconazole and anidulafungin, were determined. Blood culture isolates between 1 January 2018 and 30 June 2021 positive for spp. were included. Susceptibility testing was performed using Etest. Whole-genome-sequencing was performed using Illumina NovaSeq with bioinformatics analysis performed. A total of 203 isolates were sequenced: 56 . 53 . , 44 . 36 . complex (consisting of and ), six . five . , and three . . A single cluster of azole-resistant and four clusters of isolates were observed, suggesting possible transmission occurring over several years. We found 11.3%, and 52.7 % of and , respectively, clustered with other isolates, suggesting exogenous sources may play a significant role of transmission, particularly for . The clusters spanned over several years suggesting the possibility of environmental reservoirs contributing to the spread. Limited clonality was seen for . Several sequence types appeared to be dominant for however the SNP differences varied widely, indicating absence of sustained transmission.
Topics: Humans; Tertiary Care Centers; Drug Resistance, Fungal; Antifungal Agents; Candidemia; Candida; Genomics
PubMed: 37440287
DOI: 10.1099/mgen.0.001047 -
Microbial Biotechnology Jan 2024Invasive fungal infections have increased remarkably, which have become unprecedented concern to human health. However, the effectiveness of current antifungal drugs is... (Review)
Review
Invasive fungal infections have increased remarkably, which have become unprecedented concern to human health. However, the effectiveness of current antifungal drugs is limited due to drug resistance and toxic side-effects. It is urgently required to establish the effective biosynthetic strategy for developing novel and safe antifungal molecules economically. Echinocandins become a promising option as a mainstay family of antifungals, due to specifically targeting the fungal specific cell wall. To date, three kinds of echinocandins for caspofungin, anidulafungin, and micafungin, which derived from pneumocandin B , echinocandin B, and FR901379, are commercially available in clinic and have shown potential in managing invasive fungal infections in a cost-effective manner. However, current echinocandins-derived precursors all are produced by environmental fungal isolates with long fermentation cycle and low yields, which challenge the production efficacy of these precursors in industry. Therefore, understanding their biosynthetic machinery is of great importance for improving antifungal titres and creating new echinocandins-derived products. With the development of genome-wide sequencing and establishment of gene-editing technology, there are a growing number of reports on echinocandins-derived products and their biosynthetic gene clusters. This review briefly summarizes the discovery and development history of echinocandins, compares their structural characteristics and biosynthetic processes, and sums up existed strategies for improving their production. Moreover, the genomic analysis of related biosynthetic gene clusters of echinocandins is discussed, highlighting the similarities and differences among the clusters. Last, the biosynthetic processes of echinocandins are compared, focusing on the activation and attachment of side-chains and the formation of the hexapeptide core. This review aims to provide insights into the development and production of new echinocandin drugs by modifying the structure of echinocandin-derived precursors and/or optimizing the fermentation processes; and achieve a new microbial chassis for efficient production of echinocandins in heterologous hosts.
Topics: Humans; Antifungal Agents; Echinocandins; Fermentation; Invasive Fungal Infections; Microbial Sensitivity Tests; Lipopeptides
PubMed: 37885073
DOI: 10.1111/1751-7915.14359 -
Antimicrobial Agents and Chemotherapy Nov 2023We previously conducted a multicenter surveillance study on epidemiology and antifungal resistance in Madrid (CANDIMAD study; 2019-2021), detecting an increase in...
We previously conducted a multicenter surveillance study on epidemiology and antifungal resistance in Madrid (CANDIMAD study; 2019-2021), detecting an increase in fluconazole-resistant . We here present data on isolates collected in 2022. Furthermore, we report the epidemiology and antifungal resistance trends during the entire period, including an analysis per ward of admission. spp. incident isolates from blood cultures and intra-abdominal samples from patients cared for at 16 hospitals in Madrid, Spain, were tested with the EUCAST E.Def 7.3.2 method against amphotericin B, azoles, micafungin, anidulafungin, and ibrexafungerp and were molecularly characterized. In 2022, we collected 766 sp. isolates (686 patients; blood cultures, 48.8%). was the most common species found, and was undetected. No resistance to amphotericin B was found. Overall, resistance to echinocandins was low (0.7%), whereas fluconazole resistance was 12.0%, being higher in blood cultures (16.0%) mainly due to fluconazole-resistant clones harboring the Y132F-R398I ERG11p substitutions. Ibrexafungerp showed activity against the isolates tested. Whereas was the dominant species in most hospital wards, we observed increasing proportions in blood. During the entire period, echinocandin resistance rates remained steadily low, while fluconazole resistance increased in blood from 6.8% (2019) to 16% (2022), mainly due to fluconazole-resistant (2.6% in 2019 to 36.6% in 2022). Up to 7 out of 16 hospitals were affected by fluconazole-resistant . In conclusion, rampant clonal spreading of fluconazole-resistant genotypes is taking place in Madrid.
Topics: Humans; Fluconazole; Candida; Antifungal Agents; Amphotericin B; Candida parapsilosis; Traction; Echinocandins; Candida albicans; Drug Resistance, Fungal; Microbial Sensitivity Tests
PubMed: 38092562
DOI: 10.1128/aac.00986-23 -
Antimicrobial Agents and Chemotherapy Nov 2023Echinocandins like anidulafungin are first-line therapies for candidemia and invasive candidiasis, but their dosing may be suboptimal in obese patients. Our objective...
Echinocandins like anidulafungin are first-line therapies for candidemia and invasive candidiasis, but their dosing may be suboptimal in obese patients. Our objective was to quantify anidulafungin exposure in a cohort of adults across a wide body size range to test if body size affects anidulafungin pharmacokinetics (PK). We enrolled 20 adults between the ages of 18 and 80 years, with an equal distribution of patients above and below a body mass index of 30 kg/m. A single 100-mg dose of anidulafungin was administered, followed by intensive sampling over 72 h. Population PK analysis was used to identify and compare covariates of anidulafungin PK parameters. Monte Carlo simulations were performed to compute the probability of target attainment (PTA) based on alternative dosing regimens. Participants (45% males) had a median (range) age of 45 (21-78) years and a median (range) weight of 82.7 (42.4-208.3) kg. The observed median (range) of AUC was 106.4 (51.9, 138.4) mg∙h/L. Lean body weight (LBW) and adjusted body weight (AdjBW) were more influential than weight as covariates of anidulafungin PK parameters. The conventional 100 mg daily maintenance is predicted to have a PTA below 90% in adults with an LBW > 55 kg or an AdjBW > 75 kg. A daily maintenance dose of 150-200 mg is predicted in these heavier adults. Anidulafungin AUC declines with increasing body size. A higher maintenance dose will increase the PTA compared to the current approach in obese patients.
Topics: Adult; Male; Humans; Adolescent; Young Adult; Middle Aged; Aged; Aged, 80 and over; Female; Anidulafungin; Antifungal Agents; Obesity; Body Weight; Candidiasis, Invasive; Body Size; Monte Carlo Method
PubMed: 37850741
DOI: 10.1128/aac.00820-23 -
Emerging Microbes & Infections Dec 2023is becoming a predominant non- cause of invasive candidiasis (IC). Echinocandins are the preferred choice for IC treatment and prophylaxis. Resistance to echinocandins...
is becoming a predominant non- cause of invasive candidiasis (IC). Echinocandins are the preferred choice for IC treatment and prophylaxis. Resistance to echinocandins in has emerged in several countries, but little is known about the susceptibility profile in China or about mechanisms of resistance. Here, we investigated the echinocandin susceptibilities of 2523 isolates collected from China and further explored the resistance mechanism among echinocandin-resistant isolates. Anidulafungin exhibited the highest MICs (MIC, 1 and 2 µg/mL; GM, 0.948 µg/mL), while caspofungin showed better activity (0.5 and 1 µg/mL; 0.498 µg/mL). Significantly higher echinocandin MICs were observed among blood-derived isolates compared to others, especially for caspofungin (GM, 1.348 µg/mL vs 0.478 µg/mL). Isolates from ICU and surgical wards also showed higher MICs. Twenty isolates showed intermediate phenotypes for at least one echinocandin. One was resistant to all three echinocandins, fluconazole and voriconazole, which caused breakthrough IC during long-term exposure to micafungin. WGS revealed this isolate carried a mutation S656P in hotspot1 region of Fks1. Bioinformatics analyses suggested that this mutation might lead to an altered protein conformation. CRISPR Cas9-mediated introduction of this mutation into a susceptible reference strain increased MICs of all echinocandins 64-fold, with similar results found in the subspecies, and . This is the first report of a multi-azole resistant and pan-echinocandin resistant isolate, and the identification of a conferring pan-echinocandin resistance. Our study underscores the necessity of rigorous management of antifungal use and of monitoring for antifungal susceptibility.
Topics: Antifungal Agents; Candida parapsilosis; Candidemia; Caspofungin; China; Echinocandins; Microbial Sensitivity Tests; Humans; Drug Resistance, Fungal
PubMed: 36440795
DOI: 10.1080/22221751.2022.2153086 -
BMC Microbiology Nov 2023Candida glabrata is an important cause of invasive candidiasis. Echinocandins are the first-line treatment of invasive candidiasis caused by C. glabrata. The...
BACKGROUND
Candida glabrata is an important cause of invasive candidiasis. Echinocandins are the first-line treatment of invasive candidiasis caused by C. glabrata. The epidemiological echinocandin sensitivity requires long-term surveillance and the understanding about whole genome characteristics of echinocandin non-susceptible isolates was limited.
RESULTS
The present study investigated the echinocandin susceptibility of 1650 C. glabrata clinical isolates in China from August 2014 to July 2019. The in vitro activity of micafungin was significantly better than those of caspofungin and anidulafungin (P < 0.001), assessed by MIC values. Whole genome sequencing was conducted on non-susceptible isolates and geography-matched susceptible isolates. Thirteen isolates (0.79%) were resistant to at least one echinocandin. Six isolates (0.36%) were solely intermediate to caspofungin. Common evolutionary analysis of echinocandin-resistant and echinocandin-intermediate isolates revealed genes related with reduced caspofungin sensitivity, including previously identified sphinganine hydroxylase encoding gene SUR2. Genome-wide association study identified SNPs at subtelometric regions that were associated with echinocandin non-susceptibility. In-host evolution of echinocandin resistance of serial isolates revealed an enrichment for non-synonymous mutations in adhesins genes and loss of subtelometric regions containing adhesin genes.
CONCLUSIONS
The echinocandins are highly active against C. glabrata in China with a resistant rate of 0.79%. Echinocandin non-susceptible isolates carried common evolved genes which are related with reduced caspofungin sensitivity. In-host evolution of C. glabrata accompanied intensive changing of adhesins profile.
Topics: Humans; Echinocandins; Candida glabrata; Caspofungin; Antifungal Agents; Genome-Wide Association Study; Microbial Sensitivity Tests; Candidiasis, Invasive; China; Drug Resistance, Fungal
PubMed: 37974063
DOI: 10.1186/s12866-023-03105-3 -
Infection and Drug Resistance 2023Candidemia and antifungal resistance are major healthcare challenges. The aim of this study is to describe the frequency of candidemia cases, distribution of spp., and...
PURPOSE
Candidemia and antifungal resistance are major healthcare challenges. The aim of this study is to describe the frequency of candidemia cases, distribution of spp., and the associated risk factors for mortality in an academic institution in Saudi Arabia over an 18-month period. We also evaluated the susceptibility patterns of blood isolates.
METHODS
Candidemia cases were collected from King Fahad Hospital of the University over the period between July 1st, 2020 through December 31st, 2021. They were prospectively reviewed for the preceding risk factors and antifungal (AF) susceptibility, testing results to fluconazole (FL), voriconazole (VO), itraconazole (IT), posaconazole (PO), caspofungin (CASP), anidulafungin (AND), micafungin (MYC), flucytosine (FLC) and amphotericin B (AMPB) using a broth microdilution kit (Sensititre™ YeastOne).
RESULTS
A total of 48 candidemia isolates were included that were isolated from 43 patients. The median age of cases was 62 ± 23.3 years (60.4% males and 83% ICU patients). Independent risk factors for mortality at 30 days in candidemia patients were age, COVID-19 co-infection, and use of tocilizumab. The most commonly isolated species were and (22.9% each) followed by (18.75%). AF resistance for ≥1 antifungal was detected in 39.3% of 33 cases tested, with no cross-resistance identified. Resistance rates for each AF were as follows: FL (18%), VO (6%), IT (6%), PO (9%) and AMPB (3%). No resistance was seen for echinocandins apart from one strain showing an intermediate result for CASP.
CONCLUSION
The study showed an overall high rate of non-, with the predominance of and , representing a therapeutic challenge. AF resistance rate was high which emphasizes the importance of continuing surveillance and providing accurate and reliable tools in the laboratories for rapid speciation and susceptibility testing.
PubMed: 37457797
DOI: 10.2147/IDR.S411865