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Dalyan Cilo B, Ener B. Comparison of Clinical Laboratory Standards Institute (CLSI) Microdilution Method and VITEK 2 Automated Antifungal Susceptibility System for the Determination of Antifungal Susceptibility of Candida Species. Cureus 2021; 13:e20220. [PMID: 35004039 PMCID: PMC8733416 DOI: 10.7759/cureus.20220] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/03/2021] [Indexed: 12/20/2022] Open
Abstract
Introduction Changes in the epidemiology of Candida infections, increasing resistance, and advances in treatment have increased the need to perform antifungal susceptibility testing in clinical laboratories. Standardized reference, the microbroth dilution method, and various commercial antifungal susceptibility test systems are used to determine antifungal susceptibility. This study aims to determine and compare the antifungal susceptibility of various Candida species isolated from blood cultures in our laboratory with the CLSI M27 microdilution reference method and VITEK 2 automated system (bioMérieux, Marcy-l'Étoile, France). Methods The antifungal susceptibility of a total of 140 Candida strains to fluconazole, voriconazole, and amphotericin B, and a total of 92 strains to anidulafungin was tested with the CLSI M27 method and the VITEK 2 automated system. For fluconazole, voriconazole, and amphotericin B, essential and categorical agreement percentages were calculated between the two methods. Because there is no anidulafungin in the VITEK 2 system, anidulafungin results obtained with CLSI were compared with micafungin only in terms of categorical agreement. In the category comparison, CLSI clinical breakpoints were used; the epidemiological cut-off values were used when they were not available. Very major error, major error, and minor error rates were calculated. Results In general, the minimum inhibitory concentration (MIC) values obtained with VITEK 2 for azole group drugs were found to be one-fold higher than the CLSI MICs read at the 24th hour. While the essential agreement between the two methods was >90% for amphotericin B and voriconazole, it remained at 85% for fluconazole. Overall, the best categorical agreement was obtained with amphotericin B (99.3%), and the least categorical agreement was obtained with voriconazole (85.7%). A very major error was seen with amphotericin B (0.7%) and fluconazole (0.7%) in one C. parapsilosis strain each. No resistance was detected with VITEK 2 in one C. glabrata strain found to be resistant to fluconazole by the reference method. Major and minor error rates were higher for azole drugs than amphotericin B and anidulafungin/micafungin. Conclusion The VITEK 2 system is a fast and highly applicable system, and with these features, it is advantageous for routine laboratories. In this study, although the error rate was not very high, one fluconazole-resistant C. parapsilosis and C. glabrata strain could not be detected with VITEK 2. The increase in data on the antifungal performance of the VITEK 2 system, which is available in many routine laboratories due to its ability to be used for bacteria identification and sensitivity, will contribute to the usability of the system for this purpose. In this study, data that will support the literature information in terms of the antifungal performance of the VITEK 2 system are presented.
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Affiliation(s)
- Burcu Dalyan Cilo
- Clinical Microbiology, University of Health Sciences, Bursa Yuksek Ihtisas Training & Research Hospital, Bursa, TUR
| | - Beyza Ener
- Microbiology, Microbiology, Uludag University Medical Faculty, Bursa, TUR
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Wiederhold NP. Antifungal Susceptibility Testing: A Primer for Clinicians. Open Forum Infect Dis 2021; 8:ofab444. [PMID: 34778489 PMCID: PMC8579947 DOI: 10.1093/ofid/ofab444] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 08/26/2021] [Indexed: 12/13/2022] Open
Abstract
Clinicians treating patients with fungal infections may turn to susceptibility testing to obtain information regarding the activity of different antifungals against a specific fungus that has been cultured. These results may then be used to make decisions regarding a patient's therapy. However, for many fungal species that are capable of causing invasive infections, clinical breakpoints have not been established. Thus, interpretations of susceptible or resistant cannot be provided by clinical laboratories, and this is especially true for many molds capable of causing severe mycoses. The purpose of this review is to provide an overview of susceptibility testing for clinicians, including the methods used to perform these assays, their limitations, how clinical breakpoints are established, and how the results may be put into context in the absence of interpretive criteria. Examples of when susceptibility testing is not warranted are also provided.
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Affiliation(s)
- Nathan P Wiederhold
- Fungus Testing Laboratory, Department of Pathology and Laboratory Medicine, University of Texas Health Science Center at San Antonio, San Antonio, Texas, USA
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Species Distribution and Antifungal Susceptibility Pattern of Candida Recovered from Intensive Care Unit Patients, Vietnam National Hospital of Burn (2017-2019). Mycopathologia 2021; 186:543-551. [PMID: 34118027 DOI: 10.1007/s11046-021-00569-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 05/30/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Candida species is the most common cause of invasive fungal infection. With the wide variation in species distribution and antifungal susceptibility of causative agents, local epidemiological profiles are needed to provide effective guidelines for the treatment of invasive candidiasis. OBJECTIVE To find out the species distribution and antifungal susceptibilities of Candida strains isolated from patients in an intensive care unit (ICU) of Vietnam. METHODS All patients in ICU of Vietnam National Hospital of Burn with Candida isolation reported from January 2017 to December 2019 were retrospectively studied. Species identification and antifungal susceptibility testing were performed using VITEK 2 Compact. The identification was reconfirmed by sequencing of the internal transcribed spacer regions when needed. RESULTS A total of 186 yeasts belonging to ten species were collected. The most common agent was C. tropicalis (45.7%), followed by C. albicans (42.4%), and C. parapsilosis (7.53%). The isolated yeasts showed less susceptibility to fluconazole (resistant rate R 10.7%) than to micafungin, caspofungin, flucytosine and amphotericin B (R 0%, 0.6%, 2.3% and 3.4%, respectively, p < 0.05). C. albicans isolates were more susceptible to fluconazole (R 5.2%) than C. tropicalis (R 15.7%). Resistance to voriconazole was seen only among C. albicans (3.9%) and C. tropicalis isolates (9.9%). CONCLUSION Non-albicans species (especially C. tropicalis) is the predominant species, and there is a significant proportion of isolates with reduced susceptibility to azole but not to echinocandin.
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Al-Musawi TS, Alkhalifa WA, Alasaker NA, Rahman JU, Alnimr AM. A seven-year surveillance of Candida bloodstream infection at a university hospital in KSA. J Taibah Univ Med Sci 2020; 16:184-190. [PMID: 33897322 PMCID: PMC8046963 DOI: 10.1016/j.jtumed.2020.12.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Revised: 12/08/2020] [Accepted: 12/11/2020] [Indexed: 02/02/2023] Open
Abstract
Objectives Candidemia incidence has increased in the past few years, with high mortality. Previous studies have reported a variable distribution of Candida spp. among different regions. This study aimed to identify the species found in Candida bloodstream infections, routine antifungal susceptibility testing, and mortality outcomes in an academic medical centre. Methods Between January 2012 and December 2018, the positive blood cultures for candidemia infection were retrieved and statistically analysed for species prevalence, susceptibility pattern, and crude mortality at 14, 30, 60 and 90 days. Results Of 156 candidemia cases, a majority (69.2%) was caused by non-albicans Candida spp. After Candida albicans (30.8%), Candida tropicalis and Candida parapsilosis were the second and third most frequeunt isolates spp, each counting for 23.7%. Acquired resistance was detected in 14.8% of candidemia strains. No other antifungal resistance was detected. The overall crude mortality rates of all species were 29.3%, 47.9%, 56.4%, and 58.0% at 14, 30, 60, and 90 days, respectively. A higher mortality rate was noted in cases of Candida krusei infection (crude mortality 71.4–100%, p = 0.002). Conclusion In this study, a considerable shift to non-albicans Candida causing most bloodstream infections was observed. As such infections pose a serious threat to hospitalised patients, microbiology laboratories are urged to adopt rapid diagnostic and minimal inhibitory concentration-based testing for the detection of susceptible dose-dependent phenotypes. Prospective studies are essential to consider the prognosis of bloodstream infections by various Candida species in a multivariate model.
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Key Words
- APACHE, Acute Physiology, Age, Chronic Health Evaluation
- Antifungal susceptibility testing
- CLSI, Clinical Laboratory Standards Institute
- Candidemia
- Epidemiological shift
- FDA, Food and Drug Administration
- HR, Hazard Ratio
- MIC, Minimal inhibitory concentration
- Mortality
- NAC, non-albicans Candida spp
- Non albicans
- SDD, Susceptible dose dependent
- Spp., Species
- n, Number
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Affiliation(s)
- Tariq S Al-Musawi
- Department of Internal Medicine, King Fahad Hospital of the University, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, KSA
| | - Wala A Alkhalifa
- Department of Medical Microbiology, King Fahad Hospital of the University, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, KSA
| | - Norah A Alasaker
- Department of Internal Medicine, King Fahad Hospital of the University, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, KSA
| | - Jawad U Rahman
- Department of Microbiology, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, KSA
| | - Amani M Alnimr
- Department of Medical Microbiology, King Fahad Hospital of the University, College of Medicine, Imam Abdulrahman Bin Faisal University, Dammam, KSA
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Abstract
Fungal diseases, including those caused by (multi)drug-resistant fungi, still represent a global public health concern. Information on the susceptibility of these microorganisms to antifungal agents must be quickly produced to help clinicians initiate appropriate antifungal therapies. Unfortunately, antifungal susceptibility tests are not as developed or widely implemented as antibacterial tests, being similar in design, accuracy and reproducibility, but also laborious and slow. In this article, we review the methods of in vitro susceptibility testing, both reference (CLSI and EUCAST), commercial and new methods based on proteomics (MALDI-TOF MS) and in the detection of resistance genes by nucleic acid amplification techniques. In addi-tion, we discuss the newly established clinical breakpoints, as well as the epidemiological cut-off points, which constitute a new category that can help in the early identification of isolates that have acquired resistance mechanisms. We also discuss the advantages and limitations of each of the methods studied. Therefore, we can conclude that, although there has been much progress in studies of in vitro susceptibility testing to antifungals, there are still limitations in its application in the daily routine of microbiology labo-ratories, although it seems that the future is promising with the new technologies based on proteomics and nucleic acid amplification. Supplement information: This article is part of a supplement entitled «SEIMC External Quality Control Programme. Year 2016», which is sponsored by Roche, Vircell Microbiologists, Abbott Molecular and Francisco Soria Melguizo, S.A. © 2019 Elsevier España, S.L.U. and Sociedad Española de Enfermedades Infecciosasy Microbiología Clínica. All rights reserved.
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Knabl L, Lass-Flörl C. Antifungal susceptibility testing in Candida species: current methods and promising new tools for shortening the turnaround time. Expert Rev Anti Infect Ther 2020; 18:779-787. [PMID: 32324090 DOI: 10.1080/14787210.2020.1760841] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Invasive fungal diseases (IFDs) have received attention as an emerging public health threat, are difficult to diagnose and to treat, and are associated with substantial morbidity and mortality. The standard of care in IFD management requires an early and targeted antifungal treatment, hence covers - amongst others - species identification and antifungal susceptibility testing (AFST). AREAS COVERED This review gives an overview of methods currently applied in AFST and highlights promising new tools for shortening the turnaround time focusing on Candida species. EXPERT OPINION The performance of the broth microdilution reference methods for AFST is not suitable for daily laboratory practice as they are too labor-intensive and time-consuming. Other conventional approaches such as disk diffusion assays, epsilometer tests, colorimetric or automated approaches are easier in handling, and in part, show good correlations with the reference methods. Promising results for shortening the turnaround time in providing MIC data or resistance detection include matrix-assisted laser desorption/ionization-time of flight mass spectrometer (MALDI-TOF MS) assisted AFST, molecular-based techniques and modified conventional approaches applying direct inoculation methods. These underlying AFST concepts are promising but in part completely different, have their own advantages and disadvantages, and need further clinical validation.
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Affiliation(s)
- Ludwig Knabl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck , Innsbruck, Austria
| | - Cornelia Lass-Flörl
- Institute of Hygiene and Medical Microbiology, Medical University of Innsbruck , Innsbruck, Austria
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Abstract
Although not as ubiquitous as antibacterial susceptibility testing, antifungal susceptibility testing (AFST) is a tool of increasing importance in clinical microbiology laboratories. The goal of AFST is to reliably produce MIC values that may be used to guide patient therapy, inform epidemiological studies, and track rates of antifungal drug resistance. There are three methods that have been standardized by standards development organizations: broth dilution, disk diffusion, and azole agar screening for Aspergillus Other commonly used methods include gradient diffusion and the use of rapid automated instruments. Novel methodologies for susceptibility testing are in development. It is important for laboratories to consider not only the method of testing but also the interpretation (or lack thereof) of in vitro data.
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Borman AM, Muller J, Walsh-Quantick J, Szekely A, Patterson Z, Palmer MD, Fraser M, Johnson EM. MIC distributions for amphotericin B, fluconazole, itraconazole, voriconazole, flucytosine and anidulafungin and 35 uncommon pathogenic yeast species from the UK determined using the CLSI broth microdilution method. J Antimicrob Chemother 2020; 75:1194-1205. [DOI: 10.1093/jac/dkz568] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 10/17/2019] [Accepted: 12/19/2019] [Indexed: 12/14/2022] Open
Abstract
AbstractBackgroundEpidemiological cut-off values and clinical interpretive breakpoints have been developed for a number of antifungal agents with the most common Candida species that account for the majority of infections due to pathogenic yeasts species. However, less-common species, for which susceptibility data are limited, are increasingly reported in high-risk patients and breakthrough infections.MethodsThe UK National Mycology Reference Laboratory performs routine antifungal susceptibility testing of clinical yeast isolates submitted from across the UK. Between 2002 and 2016, >32 000 isolates representing 94 different yeast species were referred to the laboratory. Here we present antifungal susceptibility profiles generated over this period for amphotericin B, fluconazole, voriconazole, itraconazole, anidulafungin and flucytosine against 35 species of uncommon yeast using CLSI methodologies. MIC data were interpreted against epidemiological cut-off values and clinical breakpoints developed with Candida albicans, in order to identify species with unusually skewed MIC distributions that potentially indicate resistance.ResultsPotential resistance to at least one antifungal agent (>10% of isolates with MICs greater than the epidemiological cut-off or clinical breakpoint) was evidenced for 29/35 species examined here. Four species exhibited elevated MICs with all of the triazole antifungal drugs against which they were tested, and 21 species exhibited antifungal resistance to agents from at least two different classes of antifungal agent.ConclusionsThis study highlights a number of yeast species with unusual MIC distributions and provides data to aid clinicians in deciding which antifungal regimens may be appropriate when confronted with infections with rarer yeasts.
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Affiliation(s)
- Andrew M Borman
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Julian Muller
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Jo Walsh-Quantick
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Adrien Szekely
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Zoe Patterson
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Michael D Palmer
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Mark Fraser
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
| | - Elizabeth M Johnson
- PHE UK National Mycology Reference Laboratory, Science Quarter, Southmead Hospital, Bristol, UK
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Fluconazole Resistance in Isolates of Uncommon Pathogenic Yeast Species from the United Kingdom. Antimicrob Agents Chemother 2019; 63:AAC.00211-19. [PMID: 31182537 DOI: 10.1128/aac.00211-19] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 06/07/2019] [Indexed: 01/12/2023] Open
Abstract
The triazole drug fluconazole remains one of the most commonly prescribed antifungal drugs, both for prophylaxis in high-risk patients and also as a second-line treatment option for invasive Candida infections. Established susceptibility profiles and clinical interpretive breakpoints are available for fluconazole with Candida albicans, Candida glabrata, Candida tropicalis, and Candida parapsilosis, which account for the majority of infections due to pathogenic yeast species. However, less common species for which only limited susceptibility data are available are increasingly reported in high-risk patients and from breakthrough infections. The UK National Mycology Reference Laboratory performs routine antifungal susceptibility testing of clinical isolates of pathogenic yeast submitted from across the United Kingdom. Between 2002 and 2016, ∼32,000 isolates were referred, encompassing 94 different yeast species. Here, we present fluconazole antifungal susceptibility data generated using a CLSI methodology over this 15-year period for 82 species (2,004 isolates) of less common yeast and yeast-like fungi, and amphotericin B, fluconazole, itraconazole, voriconazole, posaconazole, and anidulafungin, with members of the Nakaseomyces clade (C. glabrata, Candida nivariensis, and Candida bracarensis). At least 22 different teleomorph genera, comprising 45 species, exhibited high MICs when tested with fluconazole (>20% of isolates with MICs higher than the clinical breakpoint [≥8 mg/liter] proposed for C. albicans). Since several of these species have been reported anecdotally from breakthrough infections and therapeutic failures in patients receiving fluconazole, the current study underscores the importance of rapid and accurate yeast identification and may aid clinicians dealing with infections with rarer yeasts to decide whether fluconazole would be appropriate.
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Autmizguine J, Tan S, Cohen-Wolkowiez M, Cotten CM, Wiederhold N, Goldberg RN, Adams-Chapman I, Stoll BJ, Smith PB, Benjamin DK. Antifungal Susceptibility and Clinical Outcome in Neonatal Candidiasis. Pediatr Infect Dis J 2018; 37:923-929. [PMID: 29369937 PMCID: PMC6057841 DOI: 10.1097/inf.0000000000001913] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Invasive candidiasis is an important cause of sepsis in extremely low birth weight infants (ELBW, < 1000 g), is often fatal, and frequently results in neurodevelopmental impairment (NDI) among survivors. We sought to assess the antifungal minimum inhibitory concentration (MIC) distribution for Candida in ELBW infants and evaluate the association between antifungal resistance and death or NDI. METHODS This was a secondary analysis of a National Institute of Child Health and Human Development Neonatal Research Network study. MIC values were determined for fluconazole, amphotericin B and micafungin. NDI was assessed at 18-22 months adjusted age using the Bayley Scales of Infant Development. An infant was defined as having a resistant Candida isolate if ≥ 1 positive cultures from normally sterile sites (blood, cerebrospinal fluid, or urine) were resistant to ≥ 1 antifungal agent. In addition to resistance status, we categorized fungal isolates according to MIC values (low and high). The association between death/NDI and MIC level was determined using logistic regression, controlling for gestational age and Bayley Scales of Infant Development (II or III). RESULTS Among 137 ELBW infants with IC, MICs were determined for 308 isolates from 110 (80%) infants. Three Candida isolates from 3 infants were resistant to fluconazole. None were resistant to amphotericin B or micafungin. No significant difference in death, NDI, or death/NDI between groups with low and high MICs was observed. CONCLUSIONS Antifungal resistance was rare among infecting Candida isolates, and MIC level was not associated with increased risk of death or NDI in this cohort of ELBW infants.
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MESH Headings
- Amphotericin B/pharmacology
- Antifungal Agents/pharmacology
- Antifungal Agents/therapeutic use
- Candida/drug effects
- Candida/isolation & purification
- Candidiasis, Invasive/complications
- Candidiasis, Invasive/drug therapy
- Candidiasis, Invasive/mortality
- Cohort Studies
- Drug Resistance, Fungal
- Female
- Fluconazole/pharmacology
- Gestational Age
- Humans
- Infant
- Infant, Extremely Low Birth Weight
- Infant, Newborn
- Infant, Newborn, Diseases/drug therapy
- Infant, Newborn, Diseases/microbiology
- Intensive Care Units, Neonatal/statistics & numerical data
- Male
- Micafungin/pharmacology
- Microbial Sensitivity Tests
- Neurodevelopmental Disorders/etiology
- Prospective Studies
- Sepsis/complications
- Sepsis/microbiology
- Sepsis/mortality
- Treatment Outcome
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Affiliation(s)
- Julie Autmizguine
- From the Department of Pharmacology and Physiology, Université de Montréal, Montréal, Canada
- Department of Pediatrics, Université de Montréal, Montréal, Canada
- Department of Pediatrics, Duke University, Durham, NC
| | - Sylvia Tan
- Statistics and Epidemiology Unit, RTI International, Research Triangle Park, NC
| | | | | | - Nathan Wiederhold
- University of Texas Health Science Center at San Antonio, San Antonio, TX
| | | | | | - Barbara J Stoll
- Department of Pediatrics, Emory University, Atlanta, GA
- Department of Pediatrics, McGovern Medical School at The University of Texas Health Science Center at Houston, Houston, TX
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Kidd SE, Halliday CL, Morris AJ, Chen SCA. Antifungal susceptibility testing in Australasian clinical laboratories: we must improve our performance. Pathology 2018; 50:257-260. [DOI: 10.1016/j.pathol.2018.01.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2018] [Revised: 01/25/2018] [Accepted: 01/30/2018] [Indexed: 10/17/2022]
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Copper-based metal coordination complexes with Voriconazole ligand: Syntheses, structures and antimicrobial properties. J SOLID STATE CHEM 2018. [DOI: 10.1016/j.jssc.2017.12.029] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Al-Obaid K, Asadzadeh M, Ahmad S, Khan Z. Population structure and molecular genetic characterization of clinical Candida tropicalis isolates from a tertiary-care hospital in Kuwait reveal infections with unique strains. PLoS One 2017; 12:e0182292. [PMID: 28854190 PMCID: PMC5576731 DOI: 10.1371/journal.pone.0182292] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 07/15/2017] [Indexed: 11/19/2022] Open
Abstract
Candida tropicalis is a frequently isolated yeast species causing bloodstream, urinary tract and other infections particularly in patients admitted to intensive care units (ICUs) and those requiring prolonged urinary catheterization (UC) or receiving broad-spectrum antibiotics (BSA). This study investigated clinical characteristics and genetic relatedness among C. tropicalis strains isolated from patients at Al-Amiri Hospital in Kuwait. C. tropicalis strains (n = 63) isolated from blood, genito-urinary, respiratory (RT) and digestive (GIT) tracts and wound sites from 54 patients were used. All isolates were phenotypically identified and tested against six antifungal drugs by using Vitek 2 system. Molecular identification was performed by PCR amplification of rDNA. Fingerprinting was achieved by 6-loci-based multilocus sequence typing (MLST) and data were analyzed by BioNumerics software for phylogenetic relationships. Patients mean age was >65 years and >20% patients were hospitalized in ICUs. Most patients had underlying conditions that included UC, BSA, diabetes and RT/GIT abnormalities. Most candiduria cases had UC, ureteric stent or suprapubic catheters. All isolates were identified as C. tropicalis by Vitek 2 and by species-specific PCR. Sixty-two isolates were susceptible to all tested antifungal drugs. MLST identified 59 diploid sequence types (DSTs) including 54 newly-identified DSTs. C. tropicalis isolates from multiple sites of same patient usually belonged to different DSTs. Interestingly, 56 of 57 isolates from 48 patients belonged to unique genotypes. Only six isolates from six patients belonged to three DSTs (clusters), however, C. tropicalis strains in each cluster were isolated >3 months apart. Our data show diverse origins of C. tropicalis infections in Kuwait as most isolates were unique strains. There was no obvious correlation between cluster isolates with time of isolation and/or hospital ward of their origin. This study presents the first MLST analysis of C. tropicalis isolates from Middle East and may be useful for studying genetic relationships among global C. tropicalis strains.
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Affiliation(s)
- Khaled Al-Obaid
- Microbiology, Department of Medical Laboratories, Al-Amiri Hospital, Sharq, Kuwait
| | - Mohammad Asadzadeh
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - Suhail Ahmad
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
- * E-mail:
| | - Ziauddin Khan
- Department of Microbiology, Faculty of Medicine, Kuwait University, Safat, Kuwait
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Liu WL, Lai CC, Li MC, Wu CJ, Ko WC, Hung YL, Tang HJ, Hsueh PR. Clinical manifestations of candidemia caused by uncommon Candida species and antifungal susceptibility of the isolates in a regional hospital in Taiwan, 2007-2014. JOURNAL OF MICROBIOLOGY, IMMUNOLOGY, AND INFECTION = WEI MIAN YU GAN RAN ZA ZHI 2017; 52:612-619. [PMID: 28886952 DOI: 10.1016/j.jmii.2017.08.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 08/09/2017] [Accepted: 08/09/2017] [Indexed: 12/20/2022]
Abstract
OBJECTIVE This retrospective study investigated clinical manifestations of candidemia caused by uncommon Candida species and antifungal susceptibility of the isolates in a regional hospital in Taiwan. METHODS The uncommon Candida species was initially defined as Candida species other than C. albicans, C. tropicalis, C. glabrata complex, C. parapsilosis complex and C. krusei. All uncommon Candida isolates were identified and confirmed by molecular methods. In vitro susceptibility testing of the uncommon Candida species to nine antifungal agents was conducted using the broth microdilution method with the Sensititre YeastOne (SYO) system (Trek Diagnostic Systems, Ltd., East Grimstead, UK). RESULTS Twenty-one patients, comprising 11 males and 10 females with a median age of 69 years, were recruited. Cancer (n = 11) was the most common underlying disease, 19 (90.5%) cases had prior antibiotic exposure, and only two patients had prior antifungal use. The overall in-hospital mortality rate was 38.1% (n = 8). C. guilliermondii (n = 11) was the most common pathogen, followed by C. curvata (n = 3). C. guilliermondii isolates exhibited relatively high rates of azole minimum inhibitory concentrations (MICs) above epidemiological cut-off values (ECVs), whereas C. pelliculosa and C. lusitaniae isolates all remained susceptible to azoles. All three C. curvata isolates had high caspofungin (>8 mg/L) and fluconazole MICs (8 mg/L) and could be defined as multidrug-resistant. CONCLUSIONS Uncommon Candida species frequently exhibit high rates of non-susceptibility to antifungals. Identification of all Candida isolates at the species level from blood samples is of value for treatment.
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Affiliation(s)
- Wei-Lun Liu
- Department of Emergency and Critical Care Medicine, Fu Jen Catholic University Hospital, New Taipei, Taiwan; College of Medicine, Fu Jen Catholic University, New Taipei, Taiwan
| | - Chih-Cheng Lai
- Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan
| | - Ming-Chi Li
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Chi-Jung Wu
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; National Institute of Infectious Diseases and Vaccinology, National Health Research Institutes, Tainan, Taiwan
| | - Wen-Chien Ko
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan; Center for Infection Control, National Cheng Kung University Hospital, Tainan, Taiwan
| | - Yi-Li Hung
- Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, Tainan, Taiwan; Department of Pediatrics, Cathay General Hospital, Taipei, Taiwan
| | - Hung-Jen Tang
- Department of Internal Medicine, Chi Mei Medical Center, Tainan, Taiwan; Department of Health and Nutrition, Chia Nan University of Pharmacy and Science, Tainan, Taiwan
| | - Po-Ren Hsueh
- Department of Laboratory Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan; Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan.
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González-Lara MF, Torres-González P, Rangel-Cordero A, Sifuentes-Osornio J, Ponce-de-León A, Martínez-Gamboa A. Identification and susceptibility testing of Candida spp. directly from yeast-positive blood cultures with Vitek 2. Diagn Microbiol Infect Dis 2017; 89:202-204. [PMID: 28818396 DOI: 10.1016/j.diagmicrobio.2017.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Revised: 07/07/2017] [Accepted: 07/08/2017] [Indexed: 10/19/2022]
Abstract
Culture-based identification and antifungal susceptibility take 48-72hours after positivity. We analyzed the performance of Vitek2 directly from 40 yeast-positive blood-cultures; agreement of 100% was observed for the tested antifungals; identification showed the same species in 31/40. The method reduces time (13 to 18h) for preliminary results.
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Affiliation(s)
- María Fernanda González-Lara
- Laboratory of Clinical Microbiology, Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No.15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, 14080, Mexico City, Mexico
| | - Pedro Torres-González
- Laboratory of Clinical Microbiology, Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No.15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, 14080, Mexico City, Mexico
| | - Andrea Rangel-Cordero
- Laboratory of Clinical Microbiology, Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No.15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, 14080, Mexico City, Mexico
| | - José Sifuentes-Osornio
- Department of Medicine, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No.15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, 14080, Mexico City, Mexico
| | - Alfredo Ponce-de-León
- Laboratory of Clinical Microbiology, Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No.15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, 14080, Mexico City, Mexico
| | - Areli Martínez-Gamboa
- Laboratory of Clinical Microbiology, Department of Infectious Diseases, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Avenida Vasco de Quiroga No.15, Colonia Belisario Domínguez Sección XVI, Delegación Tlalpan, 14080, Mexico City, Mexico.
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17
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Antifungal Susceptibility Testing of Candida and Cryptococcus Species and Mechanisms of Resistance: Implications for Clinical Laboratories. CURRENT FUNGAL INFECTION REPORTS 2017. [DOI: 10.1007/s12281-017-0282-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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18
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Alfouzan W, Al-Enezi T, AlRoomi E, Sandhya V, Chandy R, Khan ZU. Comparison of the VITEK 2 antifungal susceptibility system with Etest using clinical isolates of Candida species. Rev Iberoam Micol 2017. [PMID: 28622982 DOI: 10.1016/j.riam.2016.12.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Candida species are part of the normal human microbiota. However, in recent years, nosocomial bloodstream Candida infections have emerged as a significant problem ranking the fourth common cause of fungemia in intensive care units. Although microdilution methods are the ones recommended for susceptibility testing, they are difficult to undertake in the clinical practice. Thus, an automated commercially available test is ideal. AIMS To compare minimum inhibitory concentrations (MICs) obtained with the recently introduced Vitek 2 yeast susceptibility system card (AST-YS01) with Etest. METHODS 263 clinical Candida isolates representing six species were included in the study. Categorical agreements (CA) were assessed as described elsewhere. RESULTS Irrespective of the Candida species tested, the overall CA between Vitek 2 and Etest ranged between 66.7% and 100%. In general, Etest yielded lower MICs than Vitek 2. For Candida albicans, the CA between Vitek 2 and Etest was >95% for amphotericin B, voriconazole and flucytosine, but only 89% for fluconazole. With respect to Candida glabrata, the CA was between 97% and 100%. The major errors were with Candida krusei and flucytosine and Candida kefyr and amphotericin B. Candida tropicalis susceptibility for fluconazole by Vitek 2 reported more SDD and resistant strains than Etest. Candida parapsilosis showed 100% CA against all the four antifungals tested. No very major errors were detected between the two methods. CONCLUSIONS Vitek 2 provided comparable results to Etest with quick turnaround for the testing of Candida species susceptibilities.
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Affiliation(s)
- Wadha Alfouzan
- Microbiology Unit, Department of Laboratories, Farwania Hospital, Kuwait; Department of Microbiology, Faculty of Medicine, Health Sciences Center, Kuwait University, Kuwait.
| | - Tahani Al-Enezi
- Microbiology Unit, Department of Laboratories, Farwania Hospital, Kuwait
| | - Ebteehal AlRoomi
- Microbiology Unit, Department of Laboratories, Mubarak Alkabeer Hospital, Kuwait
| | - Vayalil Sandhya
- Microbiology Unit, Department of Laboratories, Mubarak Alkabeer Hospital, Kuwait
| | - Rachel Chandy
- Department of Microbiology, Faculty of Medicine, Health Sciences Center, Kuwait University, Kuwait
| | - Zia Uddin Khan
- Department of Microbiology, Faculty of Medicine, Health Sciences Center, Kuwait University, Kuwait
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Motoa G, Muñoz JS, Oñate J, Pallares CJ, Hernández C, Villegas MV. Epidemiology of Candida isolates from Intensive Care Units in Colombia from 2010 to 2013. Rev Iberoam Micol 2016; 34:17-22. [PMID: 27810262 DOI: 10.1016/j.riam.2016.02.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Revised: 11/25/2015] [Accepted: 02/12/2016] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND The frequency of Candida isolates as a cause of hospital infections has risen in recent years, leading to high rates of morbidity and mortality. The knowledge of the epidemiology of those hospital acquired fungal infections is essential to implement an adequate antifungal therapy. AIMS To describe the epidemiology of Candida infections in Intensive Care Units (ICUs) from a surveillance network in Colombia. METHODS Information was collected from the microbiology laboratories of 20 tertiary healthcare institutions from 10 Colombian cities using the Whonet® software version 5.6. A general descriptive analysis of Candida species and susceptibility profiles focusing on fluconazole and voriconazole was completed between 2010 and 2013, including a sub-analysis of healthcare associated infections (HAIs) during the last year. RESULTS Candida isolates made up 94.5% of the 2680 fungal isolates considered, with similar proportions for Candida albicans and non-C. albicans Candida species (48.3% and 51.7%, respectively). Among the latter, Candida tropicalis (38.6%) and Candida parapsilosis (28.5%) were the most frequent species. Of note, among the blood isolates C. albicans was not the main species. Most of the species isolated were susceptible to fluconazole and voriconazole. From the HAIs reported, 25.5% were caused by Candida; central line-associated bloodstream infection was the most common HAI (58.8%). There were no statistically significant differences regarding length of hospital stay and device days among HAIs. CONCLUSIONS In ICUs of Colombia, non-C. albicans Candida species are as frequent as C. albicans, except in blood samples where non-C. albicans Candida isolates predominate. Further studies are needed to evaluate Candida associated risk factors and to determine its clinical impact.
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Affiliation(s)
- Gabriel Motoa
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - Juan Sebastián Muñoz
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
| | - José Oñate
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia; Department of Internal Medicine, School of Medicine, Universidad del Valle, Cali, Colombia; Centro Medico Imbanaco, Cali, Colombia
| | | | - Cristhian Hernández
- Centro Internacional de Entrenamiento e Investigaciones Médicas (CIDEIM), Cali, Colombia
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Zhao YM, Tang GM, Wang YT, Cui YZ. Synthesis, spectroscopic studies, antimicrobial activity, and crystal structure of a Zn(II) complex based on Voriconazole. J COORD CHEM 2016. [DOI: 10.1080/00958972.2016.1247953] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Yan-Ming Zhao
- Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan, PR China
| | - Gui-Mei Tang
- Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan, PR China
| | - Yong-Tao Wang
- Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan, PR China
| | - Yue-Zhi Cui
- Department of Chemical Engineering, Shandong Provincial Key Laboratory of Fine Chemicals, Qilu University of Technology, Jinan, PR China
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Albataineh MT, Sutton DA, Fothergill AW, Wiederhold NP. Update from the Laboratory: Clinical Identification and Susceptibility Testing of Fungi and Trends in Antifungal Resistance. Infect Dis Clin North Am 2015; 30:13-35. [PMID: 26739605 DOI: 10.1016/j.idc.2015.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Despite the availability of new diagnostic assays and broad-spectrum antifungal agents, invasive fungal infections remain a significant challenge to clinicians and are associated with marked morbidity and mortality. In addition, the number of etiologic agents of invasive mycoses has increased accompanied by an expansion in the immunocompromised patient populations, and the use of molecular tools for fungal identification and characterization has resulted in the discovery of several cryptic species. This article reviews various methods used to identify fungi and perform antifungal susceptibility testing in the clinical laboratory. Recent developments in antifungal resistance are also discussed.
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Affiliation(s)
- Mohammad T Albataineh
- Fungus Testing Laboratory, Department of Pathology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Deanna A Sutton
- Fungus Testing Laboratory, Department of Pathology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Annette W Fothergill
- Fungus Testing Laboratory, Department of Pathology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
| | - Nathan P Wiederhold
- Fungus Testing Laboratory, Department of Pathology, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA.
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23
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Trabasso P, Matsuzawa T, Fagnani R, Muraosa Y, Tominaga K, Resende MR, Kamei K, Mikami Y, Schreiber AZ, Moretti ML. Isolation and drug susceptibility of Candida parapsilosis sensu lato and other species of C. parapsilosis complex from patients with blood stream infections and proposal of a novel LAMP identification method for the species. Mycopathologia 2014; 179:53-62. [PMID: 25481844 DOI: 10.1007/s11046-014-9830-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 10/31/2014] [Indexed: 11/28/2022]
Abstract
Candida parapsilosis complex (CPC) is the third Candida species isolated in blood cultures of patients from our Hospital, following C. albicans and C. tropicalis. From 2006 to 2010, the median annual distribution of CPC was 8 cases/year. Records of 36 patients were reviewed. CPC were 31 (86.1%) C. parapsilosis; 4 (11.1%) C. orthopsilosis; and 1 (2.8%) C. metapsilosis. Clinical characteristics were central venous catheter, 34 (94.4%); parental nutrition, 25 (70%); surgery, 27 (57.9%); prior bacteremia, 20 (51.3%); malignancy, 18 (50%). General mortality was 47.2%. Death was higher in immunosuppressed patients (17 vs. 11; p = 0.003). Three out four (75%) patients with C. orthopsilosis and 14 out 31 (45.2%) with C. parapsilosis died (p = 0.558). Thirty-nine individual isolates were tested for susceptibility to seven antifungal drugs, with MICs values showing susceptibility to all of them. Two isolates, one C. orthopsilosis and one C. parapsilosis, had fluconazole MIC = 4 μg/mL. Differentiation among CPC has implication in caring for patients with invasive candidiasis since there are differences in virulence, pathogenicity and drug susceptibility. A method targeting the topoisomerase II gene based on loop-mediated isothermal amplification (LAMP) was developed. LAMP emerges as a promising tool for the identification of fungal species due to the high sensitivity and specificity. LAMP can be performed at the point-of-care, being no necessary the use of expensive equipment. In our study, the method was successful comparing to the DNA sequencing and proved to be a reliable and fast assay to distinguish the three species of CPC.
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Affiliation(s)
- Plinio Trabasso
- Infectious Diseases Division, School of Medical Sciences, University of Campinas, Rua Tessália Vieira de Carvalho, 126 Cidade Universitária Zeferino Vaz, Campinas, Sao Paulo, 13083-887, Brazil,
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Posteraro B, Sanguinetti M. The future of fungal susceptibility testing. Future Microbiol 2014; 9:947-67. [DOI: 10.2217/fmb.14.55] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
ABSTRACT The antifungal treatment failures and the emergence of resistant fungal strains have stimulated the need for reproducible and clinically relevant antifungal susceptibility testing (AFST). While the standard reference methods are not intended for routine use, commercial methods are widely used for performing AFST. However, to accelerate AFST and to improve the detection of antifungal resistance, which is the most challenging goal of AFST, novel assays have been developed. Following brief drug exposures of fungal cells, the new antifungal susceptibility end points seem to provide a reliable means of identifying fungal isolates, which harbor mutations that have been associated with antifungal resistance. This article summarizes the recent progress in AFST that is destined to enhance its clinical utility in the near future.
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Affiliation(s)
- Brunella Posteraro
- Institute of Public Health, Section of Hygiene, Università Cattolica del Sacro Cuore, Largo Francesco Vito 1, Rome, Italy
| | - Maurizio Sanguinetti
- Institute of Microbiology, Università Cattolica del Sacro Cuore, Largo F. Vito 1, 00168 Rome, Italy
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Figueiredo-Carvalho MHG, Barbedo LS, Oliveira MME, Brito-Santos F, Almeida-Paes R, Zancopé-Oliveira RM. Comparison of Commercial Methods and the CLSI Broth Microdilution to Determine the Antifungal Susceptibility of Candida parapsilosis Complex Bloodstream Isolates from Three Health Institutions in Rio de Janeiro, Brazil. Mycopathologia 2014; 178:27-35. [DOI: 10.1007/s11046-014-9771-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 06/01/2014] [Indexed: 11/29/2022]
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Multicenter evaluation of the new Vitek 2 yeast susceptibility test using new CLSI clinical breakpoints for fluconazole. J Clin Microbiol 2014; 52:2126-30. [PMID: 24719450 DOI: 10.1128/jcm.00658-14] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A fully automated antifungal susceptibility test system recently updated to reflect the new species-specific clinical breakpoints (CBPs) of fluconazole for Candida (Vitek 2 AF03 yeast susceptibility test; bioMérieux, Inc., Durham, NC) was compared in three different laboratories with the Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution (BMD) method by testing 2 quality control strains, 10 reproducibility strains (4 Candida species and 6 Cryptococcus neoformans strains), and 746 isolates of Candida species (702 isolates, 13 species) and 44 isolates of C. neoformans against fluconazole. Excellent essential agreement (EA) (within 2 dilutions) between the reference and Vitek 2 MICs was observed for fluconazole and Candida species (94.0%). The EA was lower for fluconazole and C. neoformans at 86.4%. The mean times to a result with the Vitek 2 test were 9.1 h for Candida species and 12.1 h for C. neoformans. Categorical agreement (CA) between the two methods was assessed by using the new species-specific CBPs. For less common species without fluconazole CBPs, the epidemiological cutoff values (ECVs) were used to differentiate wild-type (WT; MIC, ≤ ECV) from non-WT (MIC, >ECV) strains. The CAs between the two methods were 92.0% for Candida species (0.3% very major errors [VME] and 2.6% major errors [ME]) and 84.1% for C. neoformans (4.5% VME and 11.4% ME). The updated Vitek 2 AF03 IUO yeast susceptibility system is comparable to the CLSI BMD reference method for testing the susceptibility of clinically important yeasts to fluconazole when using the new (lower) CBPs and ECVs.
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Pfaller MA, Castanheira M, Messer SA, Rhomberg PR, Jones RN. Comparison of EUCAST and CLSI broth microdilution methods for the susceptibility testing of 10 systemically active antifungal agents when tested against Candida spp. Diagn Microbiol Infect Dis 2014; 79:198-204. [PMID: 24736096 DOI: 10.1016/j.diagmicrobio.2014.03.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 02/27/2014] [Accepted: 03/05/2014] [Indexed: 11/25/2022]
Abstract
The antifungal broth microdilution (BMD) method of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) was compared with Clinical and Laboratory Standards Institute (CLSI) BMD method M27-A3 for amphotericin B, flucytosine, anidulafungin, caspofungin, micafungin, fluconazole, isavuconazole, itraconazole, posaconazole, and voriconazole susceptibility testing of 357 isolates of Candida. The isolates were selected from global surveillance collections to represent both wild-type (WT) and non-WT MIC results for the azoles (12% of fluconazole and voriconazole results were non-WT) and the echinocandins (6% of anidulafungin and micafungin results were non-WT). The study collection included 114 isolates of Candida albicans, 73 of C. glabrata, 76 of C. parapsilosis, 60 of C. tropicalis, and 34 of C. krusei. The overall essential agreement (EA) between EUCAST and CLSI results ranged from 78.9% (posaconazole) to 99.6% (flucytosine). The categorical agreement (CA) between methods and species of Candida was assessed using previously determined CLSI epidemiological cutoff values. The overall CA between methods was 95.0% with 2.5% very major (VM) and major (M) discrepancies. The CA was >93% for all antifungal agents with the exception of caspofungin (84.6%), where 10% of the results were categorized as non-WT by the EUCAST method and WT by the CLSI method. Problem areas with low EA or CA include testing of amphotericin B, anidulafungin, and isavuconazole against C. glabrata, itraconazole, and posaconazole against most species, and caspofungin against C. parapsilosis, C. tropicalis, and C. krusei. We confirm high level EA and CA (>90%) between the 2 methods for testing fluconazole, voriconazole, and micafungin against all 5 species. The results indicate that the EUCAST and CLSI methods produce comparable results for testing the systemically active antifungal agents against the 5 most common species of Candida; however, there are several areas where additional steps toward harmonization are warranted.
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