Antifungal susceptibility testing identifies the abdominal cavity as a source of Candida glabrata resistant isolates

2021 ◽  
Author(s):  
Judith Díaz-García ◽  
Aina Mesquida ◽  
Ana Gómez ◽  
Marina Machado ◽  
Pablo Martín-Rabadán ◽  
...  
Keyword(s):  
Candida Glabrata ◽  
Susceptibility Testing ◽  
Abdominal Cavity ◽  
Antifungal Susceptibility ◽  
Treatment Resistance ◽  
Resistance Rate ◽  
Blood Cultures ◽  
Wild Type ◽  
Echinocandin Resistance ◽  
Resistance Rates

To identify unrecognized niches of resistant Candida isolates and compartmentalization we retrospectively studied the antifungal susceptibility of 1,103 Candida spp. isolates from blood cultures, non-blood sterile samples, and non-sterile samples. Antifungal susceptibility was assessed by EUCAST E.Def 7.3.2; sequencing and genotyping of the FKS1-2 and ERG11 genes were carried out for non-wild type isolates. Resistance compartmentalization (presence of resistant and susceptible isogenic isolates in different anatomical sites of a given patient) was studied. Clinical charts of patients carrying non-wild type isolates were reviewed. Most isolates (63%) were Candida albicans , regardless the clinical source; Candida glabrata (27%) was the second most frequently found species in abdominal cavity samples. Fluconazole and echinocandin resistance rates were 1.5% and 1.3%, respectively, and highest in C. glabrata . We found 22 genotypes among non-wild type isolates, none of them widespread across the hospital. Fluconazole/echinocandin resistance rates of isolates from abdominal cavity (3.2%/3.2%) were significantly higher than those from blood cultures (0.7%/1.3%) ( P <0.05). Overall, fifteen patients with different forms of candidiasis were infected by resistant isolates, 80% of whom had received antifungals before or at the time of isolate collection; resistance compartmentalization was found in six patients, mainly due to C. glabrata . The highest antifungal resistance rate was detected in isolates from the abdominal cavity, mostly C. glabrata . Resistance was not caused by the spread of resistant clones, but because of antifungal treatment. Resistance compartmentalization illustrates how resistance might be overlooked if susceptibility testing is restricted to bloodstream isolates.

scholarly journals Fungemia Surveillance in Denmark Demonstrates Emergence of Non-albicans Candida Species and Higher Antifungal Usage and Resistance Rates than in Other Nations

2018 ◽  
Vol 56 (4) ◽  
pp. e01907-17 ◽  
Author(s):  
Mariana Castanheira
Keyword(s):  
Candida Albicans ◽  
Candida Species ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Fungal Species ◽  
Azole Resistance ◽  
Content Type ◽  
Fungal Organisms ◽  
Echinocandin Resistance ◽  
Resistance Rates

ABSTRACT Recent changes in the occurrence of fungal species and the difficulties in performing reference antifungal susceptibility testing highlight the importance of surveillance of fungal organisms and antifungal resistance rates. K. M. T. Astvad et al. report results from recent (2012 to 2015) fungemia surveillance in Denmark and compare the results to previous data (2004 to 2011), showing a decrease in Candida albicans infections accompanied by an increase in C. glabrata and C. dubliniensis infections (J Clin Microbiol 56:e01564-17, 2018, https://doi.org/10.1128/JCM.01564-17). Azole resistance among C. tropicalis and C. parapsilosis isolates and echinocandin resistance in C. krusei isolates were higher in Denmark than in other regions. Interestingly, the usage of antifungals is higher in Denmark than in other Nordic countries.

scholarly journals Anidulafungin Susceptibility Testing of Candida glabrata Isolates from Blood Cultures by the MALDI Biotyper Antibiotic (Antifungal) Susceptibility Test Rapid Assay

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Mansoureh Vatanshenassan ◽  
Amir Arastehfar ◽  
Teun Boekhout ◽  
Judith Berman ◽  
Cornelia Lass-Flörl ◽  
...  
Keyword(s):  
Rapid Detection ◽  
Candida Glabrata ◽  
Susceptibility Testing ◽  
Hot Spot ◽  
Antifungal Susceptibility ◽  
Blood Cultures ◽  
Susceptibility Test ◽  
Content Type ◽  
Maldi Biotyper ◽  
Antifungal Susceptibility Test

ABSTRACT Echinocandins are the recommended first-line antifungals for treatment of invasive candidiasis. The increasing number of Candida glabrata strains resistant against echinocandins is an emerging health care concern. The rapid detection of resistant C. glabrata isolates is an urgent requirement for clinical laboratories. In this study, we developed the MALDI Biotyper antibiotic (antifungal) susceptibility test rapid assay (MBT ASTRA) for the rapid detection of anidulafungin-resistant C. glabrata isolates directly from positive blood cultures. Of 100 C. glabrata strains, MBT ASTRA classified 69 as susceptible and 29 as resistant. Microdilution assays performed according to the Clinical and Laboratory Standards Institute (CLSI) guidelines, used as a standard reference, identified 65 susceptible, 9 intermediate, and 26 resistant isolates. Sequencing of hot spot 1 and hot spot 2 regions of the FKS1 and FKS2 genes classified 86 susceptible and 14 resistant isolates. The MBT ASTRA had sensitivity and specificity of 80% and 95%, respectively, compared to the microdilution method. Positive and negative agreement of MBT ASTRA was calculated at 100% and 80%, respectively, compared with the molecular sequencing approach. Together, these results revealed a high accuracy of MBT ASTRA compared to microdilution according to the CLSI and PCR analysis, resulting in a categorical agreement of 90% and 83%, respectively. The validity of MBT ASTRA was 98%. Importantly, MBT ASTRA provided antifungal susceptibility testing (AFST) within 6 h that was both accurate and reliable compared to the other two approaches, which require at least 24 h or are costly. Therefore, this method has the potential to facilitate clinical AFST rapidly at low sample costs for clinical labs already equipped with matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS).

scholarly journals In Vitro Antifungal Susceptibility Testing of Candida Isolates with the EUCAST Methodology, a New Method for ECOFF Determination

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
J. Meletiadis ◽  
I. Curfs-Breuker ◽  
J. F. Meis ◽  
J. W. Mouton
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Drugs ◽  
Second Derivative ◽  
Wild Type ◽  
Content Type ◽  
Microdilution Method ◽  
In Vitro Antifungal Susceptibility ◽  
Resistance Rates

ABSTRACT The in vitro susceptibilities of 1,099 molecularly identified clinical Candida isolates against 8 antifungal drugs were determined using the EUCAST microdilution method. A new simple, objective, and mathematically solid method for determining epidemiological cutoff values (ECOFFs) was developed by derivatizing the MIC distribution and determining the derivatized ECOFF (dECOFF) as the highest MIC with the maximum second derivative. The dECOFFs were similar (95% agreement within 1 dilution) to the EUCAST ECOFFs. Overall, low non-wild-type/resistance rates were found. The highest rates were found for azoles with C. parapsilosis (2.7 to 9.8%), C. albicans (7%), and C. glabrata (1.7 to 2.3%) and for echinocandins with C. krusei (3.3%), C. albicans (1%), and C. tropicalis (1.7%).

scholarly journals Molecular Analysis of Resistance and Detection of Non-Wild-Type Strains Using Etest Epidemiological Cutoff Values for Amphotericin B and Echinocandins for Bloodstream Candida Infections from a Tertiary Hospital in Qatar

2018 ◽  
Vol 62 (9) ◽  
Author(s):  
Saad J. Taj-Aldeen ◽  
Husam Salah ◽  
Winder B. Perez ◽  
Muna Almaslamani ◽  
Mary Motyl ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Hot Spot ◽  
Antifungal Susceptibility ◽  
Tertiary Hospital ◽  
Wild Type ◽  
Content Type ◽  
Cutoff Values ◽  
Echinocandin Resistance ◽  
Candida Infections ◽  
Type Strains

ABSTRACT A total of 301 Candida bloodstream isolates collected from 289 patients over 5 years at a tertiary hospital in Qatar were evaluated. Out of all Candida infections, 53% were diagnosed in patients admitted to the intensive care units. Steady increases in non-albicans Candida species were reported from 2009 to 2014 (30.2% for Candida albicans versus 69.8% for the other Candida species). Etest antifungal susceptibility testing was performed on all recovered clinical isolates to determine echinocandin (micafungin and anidulafungin) and amphotericin B susceptibilities and assess non-wild-type (non-WT) strains (strains for which MICs were above the epidemiological cutoff values). DNA sequence analysis was performed on all isolates to assess the presence of FKS mutations, which confer echinocandin resistance in Candida species. A total of 3.9% of isolates (12/301) among strains of C. albicans and C. orthopsilosis contained FKS hot spot mutations, including heterozygous mutations in FKS1. For C. tropicalis, the Etest appeared to overestimate strains non-WT for micafungin, anidulafungin, and amphotericin B, as 14%, 11%, and 35% of strains, respectively, had values above the epidemiological cutoff value. However, no FKS mutations were identified in this species. For all other species, micafungin best reported the echinocandin non-WT strains relative to the FKS genotype, as anidulafungin tended to overestimate non-wild-type strains. Besides C. tropicalis, few strains were classified as non-WT for amphotericin B.

Distribution and antifungal susceptibility of candida species isolated from blood culture

2021 ◽  
pp. 1-12
Author(s):  
Selim Gorgun ◽  
Melek Bilgin ◽  
Suleyman Sirri Kilic ◽  
Admin
Keyword(s):  
Candida Species ◽  
Antifungal Susceptibility ◽  
Tube Formation ◽  
Resistance Rate ◽  
Blood Cultures ◽  
Dilution Method ◽  
Ethical Approval ◽  
Immunosuppressed Patients ◽  
Training And Research ◽  
Vitek 2

Abstract Objective: The aim of this study is to determine the distribution of samples exhibiting Candida growth among the blood cultures, and the antifungal susceptibility. Methods: The retrospective study was conducted in Samsun Training and Research Hospital, Samsun, Turkey from January to December, 2018 and comprised immunosuppressed patients with sepsis. Ethical approval was obtained and consent was taken from all patients. Yeast growths were typed by means of colony morphology, germ tube formation and the VITEK 2 system. Their susceptibilities tests were determined using the same automatized system. Resistance strains were also tested using the dilution method. Results: Of the 50 patients, 19(38%) were females and 31(62%) were males. The overall mean age was 60.84 ± 22.05 years. 31 (62%) of the samples were received from intensive care units, 14 (28%) from the palliative care unit, and five from other inpatients.  In our study, most common among our isolates was C. albicans, and C. parapsiosis was most common among non-albicans species. Resistance to antifungals was observed in 28% of Candida isolates. Of the total isolates, %10 were found to be naturally resistant to fluconazole, 8% to voriconazole, 4% to flucytosine, and amphotericin B. The high resistance rate for fluconazole in Candida species is noteworthy. The findings obtained through both the dilution method and the automatized system were consistent. Continuou....

scholarly journals High prevalence of clindamycin resistance in Staphylococcus aureus blood culture isolates in São Paulo, Brazil

2017 ◽  
Vol 9 (04) ◽  
pp. 314-316 ◽  
Author(s):  
Felipe S. Lupinacci ◽  
Daniel Bussius ◽  
Felipe Acquesta ◽  
Gustavo Fam ◽  
Raphael Rossi ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Blood Culture ◽  
Susceptibility Testing ◽  
Sao Paulo ◽  
Resistance Rate ◽  
Blood Cultures ◽  
São Paulo ◽  
Inducible Clindamycin Resistance ◽  
Total Prevalence ◽  
High Prevalence

Abstract BACKGROUND: Clindamycin has become an important antimicrobial option for the treatment of Staphylococcus aureus. However, little is known about the current patterns of clindamycin-susceptibility in S. aureus invasive isolates, both in our country and in other developing countries in the world. AIMS: The aim of this study was to determine the prevalence of constitutive and inducible clindamycin resistance in methicillin-susceptible S. aureus (MSSA) and methicillin-resistant S. aureus (MRSA) blood culture isolates in São Paulo, Brazil. MATERIALS AND METHODS: From July 2011 to June 2012, all S. aureus isolates from blood cultures collected at our hospital were included in the study. Antimicrobial susceptibility testing was performed according to recommendations of the Clinical and Laboratory Standards Institute. RESULTS: Total prevalence of clindamycin resistance was 68%, including 7.2% with inducible resistance. In MRSA resistance rate was 90.8% whereas in MSSA the rate was 32.7%. CONCLUSIONS: Our high prevalence of clindamycin resistance highlights the importance of performing D-test in a routine base, as well of maintaining continued surveillance for the prevalence of clindamycin resistance.

Identification and broth-microdilution antifungal susceptibility testing of yeast directly from automated blood cultures

2020 ◽  
Vol 15 (15) ◽  
pp. 1453-1464
Author(s):  
Sourav Das ◽  
Yamini Tawde ◽  
Shreya Singh ◽  
Arunaloke Chakrabarti ◽  
Pallab Ray ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
High Sensitivity ◽  
Turnaround Time ◽  
Blood Cultures ◽  
Species Level ◽  
Robust Method ◽  
Broth Microdilution ◽  
Level Identification ◽  
Tof Ms

Aim: To standardize MALDI-TOF-MS based identification and antifungal susceptibility (AFST) for yeasts directly from automated blood cultures to reduce turnaround time. Materials & methods: Direct-ID after lysis-centrifugation (0.5% SDS) standardized in 40 and validated in 250 yeast positive samples. Direct-AFST was standardized with fluconazole (28 samples) and evaluated (70 samples) for seven antifungals. Results: Direct-ID had a high sensitivity (97.2%) and specificity (94.3%). Correct species-level identification showed 100% in C. tropicalis, C. krusei, C. parapsilosis. Direct-AFST had a 100% categorical agreement with culture-AFST for posaconazole, anidulafungin and >90% categorical agreement for amphotericin B, voriconazole and fluconazole. Conclusion: Direct-ID and subsequent direct-AFST is a rapid and robust method to reduce the turnaround time for the diagnosis of invasive candidiasis.

scholarly journals Mutations in the fks1 Gene in Candida albicans, C. tropicalis, and C. krusei Correlate with Elevated Caspofungin MICs Uncovered in AM3 Medium Using the Method of the European Committee on Antibiotic Susceptibility Testing

2008 ◽  
Vol 52 (9) ◽  
pp. 3092-3098 ◽  
Author(s):  
Marie Desnos-Ollivier ◽  
Stéphane Bretagne ◽  
Dorothée Raoux ◽  
Damien Hoinard ◽  
Françoise Dromer ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Antibiotic Susceptibility ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Clinical Isolates ◽  
Antibiotic Susceptibility Testing ◽  
Wild Type ◽  
European Committee ◽  
Rpmi Medium

ABSTRACT Mutations in two specific regions of the Fks1 subunit of 1,3-β-d-glucan synthase are known to confer decreased caspofungin susceptibility on Candida spp. Clinical isolates of Candida spp. (404 Candida albicans, 62 C. tropicalis, and 21 C. krusei isolates) sent to the French National Reference Center were prospectively screened for susceptibility to caspofungin in vitro by the broth microdilution reference method of the Antifungal Susceptibility Testing Subcommittee of the European Committee on Antibiotic Susceptibility Testing (AFST-EUCAST). Twenty-eight isolates (25 C. albicans, 2 C. tropicalis, and 1 C. krusei isolate) for which the caspofungin MIC was above the MIC that inhibited 90% of the isolates of the corresponding species (MIC90) were subjected to molecular analysis in order to identify mutations in the fks1 gene. Substitutions in the deduced protein sequence of Fks1 were found for 8 isolates, and 20 isolates had the wild-type sequence. Among the six C. albicans isolates harboring mutations, six patterns were observed involving amino acid changes at positions 641, 645, 649, and 1358. For C. tropicalis, one isolate showed an L644W mutation, and for one C. krusei isolate, two mutations, L658W and L701M, were found. Two media, RPMI medium and AM3, were tested for their abilities to distinguish between isolates with wild-type Fks1 and those with mutant Fks1. In RPMI medium, caspofungin MICs ranged from 0.25 to 2 μg/ml for wild-type isolates and from 1 to 8 μg/ml for mutant isolates. A sharper difference was observed in AM3: all wild-type isolates were inhibited by 0.25 μg/ml of caspofungin, while caspofungin MICs for all mutant isolates were ≥0.5 μg/ml. These data demonstrate that clinical isolates of C. albicans, C. tropicalis, and C. krusei with decreased susceptibility to caspofungin in vitro have diverse mutations in the fks1 gene and that AM3 is potentially a better medium than RPMI for distinguishing between mutant and wild-type isolates using the AFST-EUCAST method.

scholarly journals The Gastrointestinal Tract Is a Major Source of Echinocandin Drug Resistance in a Murine Model of Candida glabrata Colonization and Systemic Dissemination

2017 ◽  
Vol 61 (12) ◽  
Author(s):  
Kelley R. Healey ◽  
Yoji Nagasaki ◽  
Matthew Zimmerman ◽  
Milena Kordalewska ◽  
Steven Park ◽  
...  
Keyword(s):  
Candida Glabrata ◽  
Human Microbiome ◽  
Systemic Infection ◽  
Resistance Mutations ◽  
Content Type ◽  
Systemic Dissemination ◽  
Colonization Model ◽  
Echinocandin Resistance ◽  
Synthase Inhibitor ◽  
Resistance Rates

ABSTRACT Candida species are a part of the human microbiome and can cause systemic infection upon immune suppression. Candida glabrata infections are increasing and have greater rates of antifungal resistance than other species. Here, we present a C. glabrata gastrointestinal (GI) colonization model to explore whether colonized yeast exposed to caspofungin, an echinocandin antifungal, develop characteristic resistance mutations and, upon immunosuppression, breakthrough causing systemic infection. Daily therapeutic dosing (5 mg/kg of body weight) of caspofungin resulted in no reduction in fecal burdens, organ breakthrough rates similar to control groups, and resistance rates (0 to 10%) similar to those reported clinically. Treatment with 20 mg/kg caspofungin initially reduced burdens, but a rebound following 5 to 9 days of treatment was accompanied by high levels of resistance (FKS1/FKS2 mutants). Although breakthrough rates decreased in this group, the same FKS mutants were recovered from organs. In an attempt to negate drug tolerance that is critical for resistance development, we cotreated mice with daily caspofungin and the chitin synthase inhibitor nikkomycin Z. The largest reduction (3 log) in GI burdens was obtained within 3 to 5 days of 20 mg/kg caspofungin plus nikkomycin treatment. Yet, echinocandin resistance, characterized by a novel Fks1-L630R substitution, was identified following 5 to 7 days of treatment. Therapeutic caspofungin plus nikkomycin treatment left GI burdens unchanged but significantly reduced organ breakthrough rates (20%; P < 0.05). Single-dose pharmacokinetics demonstrated low levels of drug penetration into the GI lumen posttreatment with caspofungin. Overall, we show that C. glabrata echinocandin resistance can arise within the GI tract and that resistant mutants can readily disseminate upon immunosuppression.

scholarly journals Genetic Analysis of Candida glabrata from Candiduric Patients Using Microsatellite Length Polymorphism, Antifungal Susceptibility, and Enzymatic Profiles

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Maral Gharaghani ◽  
Ali Rezaei-Matehkolaei ◽  
Amir Kamal Hardani ◽  
Ali Zarei Mahmoudabadi
Keyword(s):  
Enzymatic Activity ◽  
Microsatellite Markers ◽  
Length Polymorphism ◽  
Spanning Tree ◽  
Candida Glabrata ◽  
Minimum Spanning Tree ◽  
Antifungal Susceptibility ◽  
Wild Type ◽  
High Genetic Diversity ◽  
Microsatellite Length Polymorphism

Background: Candida glabrata is the second agent of candiduria with increased resistance to antifungals. Microsatellite length polymorphism (MLP) is one of the genotyping techniques used in the epidemiological investigation to improve clinical management. Objectives: We aimed to detect different genotypes of C. glabrata isolates using six microsatellite markers and the MLP technique. Moreover, our genotypes' association with other countries' genotypes was illustrated using a minimum spanning tree. We investigated in vitro antifungal susceptibility and enzymatic activity profiles of the isolates. Methods: Six microsatellite markers were amplified using multiplex-PCR for 22 C. glabrata strains isolated from urine in pediatric patients admitted to the Abuzar Children's Hospital in Ahvaz, Iran. The PCR products were presented for fragment analysis, and the size of the alleles was determined. Antifungal susceptibility tests and extracellular enzyme activities were also performed. Results: Nineteen multilocus genotypes were detected so that 22.7% of the strains had identical genotypes. The isolates were wild-type for amphotericin B (0.0625 - 2 µg/mL), itraconazole (0.125 - 2 µg/mL), and voriconazole (0.0078 - 0.00625 µg/mL). All the isolates were sensitive to fluconazole at the minimum inhibitory concentration (MIC) range (0.0312 - 16 μg/mL), and three of them were resistant to caspofungin (MIC ≥ 0.5 μg/mL). Moreover, 72.7 and 68.2% of the isolates had no phospholipase and esterase activities. The highest potency of enzymatic activity was obtained in hemolysin and proteinase enzymes. A high genetic diversity (19 genotypes of the 22 isolates) existed among the urinary C. glabrata isolates. Based on the minimum spanning tree, two clusters of our genotypes were related to C. glabrata genotypes in a previous study in Iran, and the third cluster was entirely connected with Chinese genotypes. Conclusions: Most of the isolates were the non-wild type for posaconazole but were rarely resistant to other antifungals. Hemolysin and proteinase secreted as the main virulence factors among the urinary C. glabrata isolates.

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