1
|
A computer vision chemometric-assisted approach to access pH and glucose influence on susceptibility of Candida pathogenic strains. Arch Microbiol 2022; 204:530. [PMID: 35900475 DOI: 10.1007/s00203-022-03145-9] [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: 02/15/2022] [Revised: 07/12/2022] [Accepted: 07/18/2022] [Indexed: 11/02/2022]
Abstract
Microorganisms adapt to environmental conditions as a survival strategy for different interactions with the environment. The adaptive capacity of fungi allows them to cause disease at various sites of infection in humans. In this study, we propose digital images as responses of a complete factorial 23. Furthermore, we compared two experimental approaches: the experimental design (3D) and the checkerboard assay (2D) to know the influence of pH, glucose, and fluconazole concentration on different strains of the genus Candida. The digital images obtained from the factorial 23 were used as input in the PCA-ANOVA to analyze the results of this experimental design. pH modification in the culture medium modifies the susceptibility in some species less adapted to this type of modification. For the first time, to the best of our knowledge, digital images were used as input to PCA-ANOVA to obtain information on Candida spp.. Therefore, a higher concentration of antifungals is needed to inhibit the same strain at a lower pH. In short, we present an alternative with less use of reagents and time. In addition, the use of digital images allows obtaining information about fungal susceptibility with three or more factors.
Collapse
|
2
|
de Sousa ESO, Pinheiro SB, Cortez ACA, Cruz KS, de Souza ÉS, Melhem MDSC, Frickmann H, de Souza JVB. Modifications of antifungal sensibility testing as suggested by CLSI document M27-A4: proposal for using different culture medium and buffer. Diagn Microbiol Infect Dis 2021; 101:115488. [PMID: 34461499 DOI: 10.1016/j.diagmicrobio.2021.115488] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 11/24/2022]
Abstract
A common strategy in antifungal susceptibility testing is the utilization of the standardized protocol based on the microbroth dilution assay approach as described by the Clinical Laboratory Standards Institute (CLSI) (M27-A4). One major problem for laboratories in resource-limited countries with this protocol arises from the use of expensive culture media like RPMI-1640 and 3-N-morpholinopropanesulfonic acid (MOPS) buffer. One approach of circumventing this problem in cases of economic need is the evaluation of alternative culture media and buffers. The overall goal of this work was to investigate the influence of modifications in the protocol M27-A4 on diagnostic reliability. We performed univariate analyses evaluating (1) 2 different culture media (YNB and modified SAB); (2) three different buffers (sodium bicarbonate, Tris-HCL, and phosphate), as well as the influence of inoculum concentration (102, 103, 104, 105 cells/mL), the influence of incubation time, and the influence of the assessment mode (visual, biological dye, and spectrophotometer). Our results suggested that (1) RPMI-1640 may be substituted by modified SAB and (2) MOPS buffer may be substituted by Tris-HCl buffer for defined analyses. By comparing the CLSI protocol and the alternative protocol proposed in the present study (modified SAB and Tris-HCl buffer) for the assessment of fluconazole susceptibility of eighteen yeasts (clinical isolates), similar results with both methodologies were recorded. We feel that this study should stimulate a discussion on the feasibility and evolution of the M27-A4 protocol in order to include pragmatic alternatives for resource-limited settings.
Collapse
Affiliation(s)
| | - Silviane Bezerra Pinheiro
- Programa de Pós-graduação em Ciências Farmacêuticas - Universidade Federal do Amazonas - UFAM, Amazonas, Brasil
| | - Ana Cláudia Alves Cortez
- Departamento de Microbiologia Médica, Instituto Nacional de Pesquisa da Amazônia - INPA. Av. André Araújo, Amazonas, Brasil
| | - Kátia Santana Cruz
- Fundação de Medicina Tropical Doutor Heitor Vieira Dourado - AM, Manaus, Amazonas, Brasil
| | | | - Marcia de Souza Carvalho Melhem
- The School of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Brazil; Departamento de Micologia, Instituto Adolfo Lutz. Av. Dr Arnaldo, São Paulo, Brasil
| | - Hagen Frickmann
- Department of Microbiology and Hospital Hygiene, Bundeswehr Hospital Hamburg, Hamburg, Germany; Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - João Vicente Braga de Souza
- Departamento de Microbiologia Médica, Instituto Nacional de Pesquisa da Amazônia - INPA. Av. André Araújo, Amazonas, Brasil.
| |
Collapse
|
3
|
de Sousa ESO, Cortez ACA, de Souza Carvalho Melhem M, Frickmann H, de Souza JVB. Factors influencing susceptibility testing of antifungal drugs: a critical review of document M27-A4 from the Clinical and Laboratory Standards Institute (CLSI). Braz J Microbiol 2020; 51:1791-1800. [PMID: 32757139 DOI: 10.1007/s42770-020-00354-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 07/29/2020] [Indexed: 12/24/2022] Open
Abstract
Due to the increasing numbers of fungal infections and the emergence of drug-resistant fungi, optimization and standardization of diagnostic methods for the measurement of antifungal susceptibility are ongoing. The M27-A4 document by the US Clinical and Laboratory Standards Institute (CLSI) is presently used for the interpretation of minimum inhibitory concentrations of major opportunistic yeast species as measured by broth microdilution testing in many countries. Although microdilution is considered a benchmark for reproducible and accurate results, increased testing capacity, and limited human bias, the method is often inaccessible to routine clinical laboratories and researchers, especially in low-income countries. Furthermore, several studies suggest that there are still a considerable number of factors that make the estimation of in vitro activity of antifungal agents challenging. This review article summarizes the limitations of the M27-A4 standard which, despite the advances and improvements obtained by the standardization of antimicrobial resistance testing methods by CLSI, still persist.
Collapse
Affiliation(s)
| | - Ana Claúdia Alves Cortez
- Department of Medical Microbiology, National Institute for Amazonian Research - INPA, André Araújo Avenue, Manaus, Amazonas, Brazil
| | - Marcia de Souza Carvalho Melhem
- Department of Mycology, Adolfo Lutz Institute, Av. Dr. Arnaldo, Sao Paulo, Brazil
- School of Medicine, Federal University of Mato Grosso do Sul, Campo Grande, Mato Grosso do Sul, Brazil
| | - Hagen Frickmann
- Department of Tropical Medicine at the Bernhard Nocht Institute, German Armed Forces Hospital of Hamburg, Hamburg, Germany, Institute for Medical Microbiology, Virology and Hygiene, University Medicine Rostock, Rostock, Germany
| | - João Vicente Braga de Souza
- Department of Medical Microbiology, National Institute for Amazonian Research - INPA, André Araújo Avenue, Manaus, Amazonas, Brazil.
| |
Collapse
|
4
|
Mitochondrial Cochaperone Mge1 Is Involved in Regulating Susceptibility to Fluconazole in Saccharomyces cerevisiae and Candida Species. mBio 2017; 8:mBio.00201-17. [PMID: 28720726 PMCID: PMC5516249 DOI: 10.1128/mbio.00201-17] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
MGE1 encodes a yeast chaperone involved in Fe-S cluster metabolism and protein import into the mitochondria. In this study, we identified MGE1 as a multicopy suppressor of susceptibility to the antifungal fluconazole in the model yeast Saccharomyces cerevisiae. We demonstrate that this phenomenon is not exclusively dependent on the integrity of the mitochondrial DNA or on the presence of the drug efflux pump Pdr5. Instead, we show that the increased dosage of Mge1 plays a protective role by retaining increased amounts of ergosterol upon fluconazole treatment. Iron metabolism and, more particularly, Fe-S cluster formation are involved in regulating this process, since the responsible Hsp70 chaperone, Ssq1, is required. Additionally, we show the necessity but, by itself, insufficiency of activating the iron regulon in establishing the Mge1-related effect on drug susceptibility. Finally, we confirm a similar role for Mge1 in fluconazole susceptibility in the pathogenic fungi Candida glabrata and Candida albicans. Although they are mostly neglected compared to bacterial infections, fungal infections pose a serious threat to the human population. While some of them remain relatively harmless, infections that reach the bloodstream often become lethal. Only a few therapies are available, and resistance of the pathogen to these drugs is a frequently encountered problem. It is thus essential that more research is performed on how these pathogens cope with the treatment and cause recurrent infections. Baker’s yeast is often used as a model to study pathogenic fungi. We show here, by using this model, that iron metabolism and the formation of the important iron-sulfur clusters are involved in regulating susceptibility to fluconazole, the most commonly used antifungal drug. We show that the same process likely also occurs in two of the most regularly isolated pathogenic fungi, Candida glabrata and Candida albicans.
Collapse
|
5
|
Zomorodian K, Bandegani A, Mirhendi H, Pakshir K, Alinejhad N, Poostforoush Fard A. In Vitro Susceptibility and Trailing Growth Effect of Clinical Isolates of Candida Species to Azole Drugs. Jundishapur J Microbiol 2016; 9:e28666. [PMID: 27127587 PMCID: PMC4841996 DOI: 10.5812/jjm.28666] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2015] [Revised: 10/10/2015] [Accepted: 11/30/2015] [Indexed: 01/12/2023] Open
Abstract
Background: Emergence of resistance to respective antifungal drugs is a primary concern for the treatment of candidiasis. Hence, determining antifungal susceptibility of the isolated yeasts is of special importance for effective therapy. For this purpose, the clinical laboratory standard institute (CLSI) has introduced a broth microdilution method to determine minimum inhibitory concentration (MIC). However, the so-called “Trailing effect” phenomenon might sometimes pose ambiguity in the interpretation of the results. Objectives: The present study aimed to determine the in vitro susceptibility of clinical isolates of Candida against azoles and the frequency of the Trailing effect. Materials and Methods: A total of 193 Candida isolates were prospectively collected and identified through the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Using a broth microdilution test, according to the guidelines of CLSI M27-A3, antifungal susceptibilities of the isolated yeasts against Fluconazole (FLU), Itraconazole (ITR), Ketoconazole (KET) and Voriconazole (VOR) were assessed. Moreover, trailing growth was determined when a susceptible MIC was incubated for 24 hours, and turned into a resistant one after 48 hours of incubation. Results: Among the tested antifungal drugs in this study, the highest rate of resistance was observed against ITR (28.5%) followed by VOR (26.4%), FLU (20.8%) and KET (1.5%). The trailing effect was induced in 27 isolates (14.0%) by VOR, in 26 isolates (13.5%) by ITR, in 24 isolates (12.4%) by FLU, and in 19 isolates (9.8%) by KET. Conclusions: The monitoring of antifungal susceptibilities of Candida species isolated from clinical sources is highly recommended for the efficient management of patients. Moreover, the trailing effect should be taken into consideration once the interpretation of the results is intended.
Collapse
Affiliation(s)
- Kamiar Zomorodian
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Azadeh Bandegani
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Hossein Mirhendi
- Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Keyvan Pakshir
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Department of Medical Mycology and Parasitology, School of Medicine, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Navvab Alinejhad
- Student Research Committee, Shiraz University of Medical Sciences, Shiraz, IR Iran
| | - Ali Poostforoush Fard
- Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran
- Corresponding author: Ali Poostforoush Fard, Basic Sciences in Infectious Diseases Research Center, Shiraz University of Medical Sciences, Shiraz, IR Iran. Tel: +98-7112305291, Fax: +98-7112305291, E-mail:
| |
Collapse
|
6
|
Thatai P, Tiwary AK, Sapra B. Progressive development in experimental models of transungual drug delivery of anti-fungal agents. Int J Cosmet Sci 2015; 38:1-12. [PMID: 25919363 DOI: 10.1111/ics.12230] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 04/15/2015] [Indexed: 12/31/2022]
Abstract
Pre-clinical development comprises of different procedures that relate drug discovery in the laboratory for commencement of human clinical trials. Pre-clinical studies can be designed to recognize a lead candidate from a list to develop the procedure for scale-up, to choose the unsurpassed formulation, to determine the frequency, and duration of exposure; and eventually make the foundation of the anticipated clinical trial design. The foremost aim in the pharmaceutical research and industry is the claim of drug product quality throughout a drug's life cycle. The particulars of the pre-clinical development process for different candidates may vary; however, all have some common features. Typically in vitro, in vivo or ex vivo studies are elements of pre-clinical studies. Human pharmacokinetic in vivo studies are often supposed to serve as the 'gold standard' to assess product performance. On the other hand, when this general assumption is revisited, it appears that in vitro studies are occasionally better than in vivo studies in assessing dosage forms. The present review is compendious of different such models or approaches that can be used for designing and evaluation of formulations for nail delivery with special reference to anti-fungal agents.
Collapse
Affiliation(s)
- P Thatai
- Pharmaceutics Division, Department of Pharmaceutical Sciences & Drug Research, Punjabi University, Patiala, India
| | - A K Tiwary
- Pharmaceutics Division, Department of Pharmaceutical Sciences & Drug Research, Punjabi University, Patiala, India
| | - B Sapra
- Pharmaceutics Division, Department of Pharmaceutical Sciences & Drug Research, Punjabi University, Patiala, India
| |
Collapse
|
7
|
Leon CG, Lee J, Bartlett K, Gershkovich P, Wasan EK, Zhao J, Clement JG, Wasan KM. In vitro cytotoxicity of two novel oral formulations of Amphotericin B (iCo-009 and iCo-010) against Candida albicans, human monocytic and kidney cell lines. Lipids Health Dis 2011; 10:144. [PMID: 21854638 PMCID: PMC3173361 DOI: 10.1186/1476-511x-10-144] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 08/20/2011] [Indexed: 11/13/2022] Open
Abstract
Background Invasive fungal infections such as candidiasis constitute an increasingly important medical problem. Drugs currently used for the treatment of candidiasis include polyenes (such as Amphotericin B) and azoles. Amphotericin B (AmpB) presents several limitations such as its nephrotoxicity and limited solubility. We have developed two novel lipid-based AmpB formulations which in vivo show less nephrotoxicity and enhanced solubility compared to Fungizone™ a commercial AmpB formulation. The purpose of this study was to determine the cytotoxicity of Fungizone™, Ambisome™ and two novel AmpB formulations (iCo-009 and iCo-010) against Candida albicans, human kidney (293T) cells and monocytic (THP1) cells. Methods Cell cytotoxicity to the AmpB formulations was evaluated by MTS and LDH assays. In vitro anti-Candida albicans activity was assessed after a 48 h drug incubation. Results None of the AmpB formulations tested showed cytotoxicity against 293T cells. In the case of THP1 cells only Fungizone™ and Ambisome™ showed cytotoxicity at 500 μg/L (n = 4-10, p < 0.05). The calculated EC50 to Candida albicans for the different formulations was as follows: 26.8 ± 2.9 for iCo-010, 74.6 ± 8.9 for iCo-009, 109 ± 31 for Ambisome™ and 87.1 ± 22 for Fungizone™ (μg of AmpB/L, n = 6-12, p < 0.05). Conclusions The AmpB formulations analyzed were not cytotoxic to 293T cells. Cytotoxicity in THP1 cells was observed for Fungizone™ and Ambisome™, but not with the novel AmpB formulations. iCo-010 had higher efficacy compared to other three AmpB formulations in the Candida albicans model. The absence of cytotoxicity as well as its higher efficacy for the Candida model compared to Fungizone™ and Ambisome™ suggest that iCo-010 has potential in treating candidiasis.
Collapse
Affiliation(s)
- Carlos G Leon
- Division of Pharmaceutics and Biopharmaceutics, The University of British Columbia, Vancouver British Columbia, V6T 1Z3, Canada
| | | | | | | | | | | | | | | |
Collapse
|
8
|
T-2307 shows efficacy in a murine model of Candida glabrata infection despite in vitro trailing growth phenomena. Antimicrob Agents Chemother 2010; 54:3630-4. [PMID: 20547803 DOI: 10.1128/aac.00355-10] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
T-2307, a novel arylamidine, has been shown to exhibit broad-spectrum in vitro and in vivo antifungal activities against clinically significant pathogens. In our preliminary studies, Candida glabrata exhibited significant trailing growth (partial inhibition of growth over an extended range of antifungal concentrations) in the presence of T-2307 when it was tested using the Clinical and Laboratory Standards Institute (CLSI) guidelines with 0.2% glucose and 48 h of incubation, making reading of the MIC difficult. In the present study, we attempted to attenuate trailing growth to avoid misreading of the MIC. On the basis of the hypothesis that T-2307 may inhibit the mitochondrial functions of cells, the carbon source or the glucose concentration in the medium was changed. The trailing growth of C. glabrata ATCC 90030 in the presence of T-2307 was attenuated as the concentration of glucose in the medium decreased to 0.1% or lower, and trailing growth was completely inhibited when glycerol was used. A susceptibility test using Alamar blue was performed to facilitate reading of the MIC without changing the composition of the medium and provided a clear MIC endpoint at 24 h. To investigate if T-2307 shows efficacy against trailing isolates in vivo, we evaluated the efficacy of T-2307 in a murine model of disseminated candidiasis caused by C. glabrata. T-2307 at 0.05 mg/kg of body weight/day significantly decreased the viable count in the kidneys compared to that for the control group (P < 0.05). It would be better to test the susceptibility of C. glabrata to T-2307 using modified media or Alamar blue to avoid misreading of the MIC due to the significant trailing growth.
Collapse
|
9
|
EUCAST definitive document EDef 7.1: method for the determination of broth dilution MICs of antifungal agents for fermentative yeasts. Clin Microbiol Infect 2008; 14:398-405. [PMID: 18190574 DOI: 10.1111/j.1469-0691.2007.01935.x] [Citation(s) in RCA: 376] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
10
|
Rodriguez-Tudela JL, Donnelly JP, Pfaller MA, Chryssantou E, Warn P, Denning DW, Espinel-Ingroff A, Barchiesi F, Cuenca-Estrella M. Statistical analyses of correlation between fluconazole MICs for Candida spp. assessed by standard methods set forth by the European Committee on Antimicrobial Susceptibility Testing (E.Dis. 7.1) and CLSI (M27-A2). J Clin Microbiol 2007; 45:109-11. [PMID: 17093015 PMCID: PMC1828996 DOI: 10.1128/jcm.01969-06] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2006] [Revised: 10/17/2006] [Accepted: 10/25/2006] [Indexed: 11/20/2022] Open
Abstract
The European Committee on Antimicrobial Susceptibility Testing (EUCAST) Subcommittee on Antifungal Susceptibility Testing recently published a standard for determining the susceptibility of fermentative yeasts to antifungals. From the beginning, the EUCAST and its North American counterpart, the CLSI, decided to work together in order to establish common standards. As part of this exercise, the susceptibility of a set of 475 yeast isolates was tested by both standards. The intraclass correlation coefficient and the equations defining the linear regression between both methods were estimated. Both methods produced very similar results, with an intraclass correlation coefficient of 0.954 (0.945 to 0.962), although linear regression analysis shows that the EUCAST standard resulted in slightly lower MICs. There were only eight isolates showing at least four twofold dilution MIC differences between both standards. After 24 h of incubation, the MICs obtained by the CLSI method were equivalent to those obtained by the EUCAST standard. In summary, both methods produce very similar MICs, indicating that methodology does not pose any obstacle to obtaining uniform standards for antifungal susceptibility testing of yeasts.
Collapse
Affiliation(s)
- Juan Luis Rodriguez-Tudela
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda Pozuelo km 2, 28220 Majadahonda, Madrid, Spain.
| | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Rodríguez-Tudela J, Barchiesi F, Bille J, Chryssanthou E, Cuenca-Estrella M, Denning D, Donnelly J, Dupont B, Fegeler W, Moore C, Richardson M, Verweij P. Method for the determination of minimum inhibitory concentration (MIC) by broth dilution of fermentative yeasts. Clin Microbiol Infect 2003. [DOI: 10.1046/j.1469-0691.2003.00789.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
12
|
Seibold M, Tintelnot K. Susceptibility testing of fungi--current status and open questions. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 2003; Spec No:191-241. [PMID: 12675477 DOI: 10.1007/978-3-0348-7974-3_5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
The increase of fungal infections and the improvement of therapeutical options demand reliable antifungal susceptibility testing. In vitro susceptibility testing of fungi--in contrast to bacteria--is not yet established as a routine method. The NCCIS (National Committee for Clinical Laboratory Standards) guidelines for susceptibility testing of yeasts (and proposed for hyphomycetes) are most important for standardization. Meanwhile, essential parts of this test procedure are accepted, but it should still be improved. The concept of using only one test medium for all drugs and test organisms is not realized so far. There are also some test situations that prevent the NCCLS standard from being applied. Based on our experience, this article describes the NCCLS methods and their modifications. It places emphasis on lipophilic drugs showing controversies despite standardization. Furthermore, the prediction of MICs on the clinical outcome is discussed. Since there are some pitfalls in testing antifungals, this should be done in experienced laboratories only. The MIC has to be regarded as only one, but an important, factor in the management of fungal diseases. Host-, drug-, and pathogen-specific data should be considered simultaneously.
Collapse
Affiliation(s)
- Michael Seibold
- Robert Koch-Institut, Mykologie, Nordufer 20, 13353 Berlin, Germany
| | | |
Collapse
|
13
|
Borg-von Zepelin M, Niederhaus T, Gross U, Seibold M, Monod M, Tintelnot K. Adherence of different Candida dubliniensis isolates in the presence of fluconazole. AIDS 2002; 16:1237-44. [PMID: 12045488 DOI: 10.1097/00002030-200206140-00005] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The recently described yeast species Candida dubliniensis is closely related to C. albicans and has been recovered predominantly from the oral cavities of HIV-infected individuals and AIDS patients who are often receiving fluconazole as prophylactic or therapeutic treatment for oropharyngeal candidiasis. Like C. albicans, C. dubliniensis secretes aspartic proteinases which in C. albicans have been shown to be involved in adherence. OBJECTIVE To explain the increasing prevalence of C. dubliniensis in AIDS patients and to investigate the virulence factors of this yeast. METHODS An in vitro assay was developed to compare the adherence to epithelial cells of C. dubliniensis from HIV-patients with that of C. albicans. RESULTS All C. albicans isolates adhered better than the 22 C. dubliniensis isolates. In the presence of fluconazole, the C. dubliniensis isolates tested showed increased adherence as compared with controls without fluconazole. In contrast, all C. albicans isolates decreased in adherence to epithelial cells in the presence of fluconazole independently of their in vitro susceptibility to this drug. Proteinase antigens are present on the surface of C. dubliniensis cells adherent to epithelial target cells. In the presence of fluconazole this proteinase antigen was more strongly expressed. CONCLUSION Increased adherence of C. dubliniensis strains in the presence of fluconazole could explain its high recovery rate from HIV-positive patients in recent years. The induction of proteinase secretion in the presence of fluconazole found for most of the C. dubliniensis isolates could be one of the factors involved in adherence.
Collapse
|
14
|
Silva MDRR, Costa MR, Miranda ATB, Fernandes ODFL, Costa CR, Paula CRD. Evaluation of Etest and macrodilution broth method for antifungal susceptibility testing of Candida sp strains isolated from oral cavities of AIDS patients. Rev Inst Med Trop Sao Paulo 2002; 44:121-5. [PMID: 12163903 DOI: 10.1590/s0036-46652002000300002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
A comparison of the Etest and the reference broth macrodilution susceptibility test for fluconazole, ketoconazole, itraconazole and amphotericin B was performed with 59 of Candida species isolated from the oral cavities of AIDS patients. The Etest method was performed according to the manufacturer's instructions, and the reference method was performed according to National Committee for Clinical Laboratory Standards document M27-A guidelines. Our data showed that there was a good correlation between the MICs obtained by the Etest and broth dilution methods. When only the MIC results at +/- 2 dilutions for both methods were considered, the agreement rates were 90.4% for itraconazole, ketoconazole and amphotericin B and 84.6% for fluconazole of the C. albicans tested. In contrast, to the reference method, the Etest method classified as susceptible three fluconazole-resistant isolates and one itraconazole-resistant isolate, representing four very major errors. These results indicate that Etest could be considered useful for antifungal sensitivity evaluation of yeasts in clinical laboratories.
Collapse
Affiliation(s)
- Maria do Rosário R Silva
- Instituto de Patologia Tropical e Saúde Pública, Universidade Federal de Goiás, Goiânia, GO, Brasil.
| | | | | | | | | | | |
Collapse
|
15
|
Cuenca-Estrella M, Rodríguez-Tudela JL. Present status of the detection of antifungal resistance: the perspective from both sides of the ocean. Clin Microbiol Infect 2002; 7 Suppl 2:46-53. [PMID: 11525218 DOI: 10.1111/j.1469-0691.2001.tb00009.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The NCCLS reference methodology for antifungal susceptibility testing is a new milestone of the evolution of medical mycology. The use of this methodology however, is not problem-free. At present, major limitations are a trailing phenomenon with azoles, unreliable detection of resistance to amphotericin B, poor growth of some organisms and unpractical procedures for the clinical laboratory. Herein a overview of NCCLS guidelines for yeasts and filamentous fungi is presented. Likewise, a review of studies conducted trying to overcome the limitations of reference procedures is also included. Several alternative approaches are reviewed as alternative media, inoculum size and incubation time. Modifications of reading procedure and endpoint determination are also evaluated. Agar diffusion methods and other methods for susceptibility testing are cited. Finally, we discuss the data on correlation of the in vitro results with the in vivo activity.
Collapse
Affiliation(s)
- M Cuenca-Estrella
- Servicio de Micrología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain.
| | | |
Collapse
|
16
|
Rex JH, Pfaller MA, Walsh TJ, Chaturvedi V, Espinel-Ingroff A, Ghannoum MA, Gosey LL, Odds FC, Rinaldi MG, Sheehan DJ, Warnock DW. Antifungal susceptibility testing: practical aspects and current challenges. Clin Microbiol Rev 2001; 14:643-58, table of contents. [PMID: 11585779 PMCID: PMC88997 DOI: 10.1128/cmr.14.4.643-658.2001] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Development of standardized antifungal susceptibility testing methods has been the focus of intensive research for the last 15 years. Reference methods for yeasts (NCCLS M27-A) and molds (M38-P) are now available. The development of these methods provides researchers not only with standardized methods for testing but also with an understanding of the variables that affect interlaboratory reproducibility. With this knowledge, we have now moved into the phase of (i) demonstrating the clinical value (or lack thereof) of standardized methods, (ii) developing modifications to these reference methods that address specific problems, and (iii) developing reliable commercial test kits. Clinically relevant testing is now available for selected fungi and drugs: Candida spp. against fluconazole, itraconazole, flucytosine, and (perhaps) amphotericin B; Cryptococcus neoformans against (perhaps) fluconazole and amphotericin B; and Aspergillus spp. against (perhaps) itraconazole. Expanding the range of useful testing procedures is the current focus of research in this area.
Collapse
Affiliation(s)
- J H Rex
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas 77030, USA.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Cuenca-Estrella M, Díaz-Guerra TM, Mellado E, Rodríguez-Tudela JL. Detection of resistance to amphotericin B in Candida isolates by using Iso-Sensitest broth. Antimicrob Agents Chemother 2001; 45:2070-4. [PMID: 11408225 PMCID: PMC90602 DOI: 10.1128/aac.45.7.2070-2074.2001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major limitation of the National Committee for Clinical Laboratory Standards M27-A methodology is reliable detection of amphotericin B (AMB) resistance. The results obtained by using Iso-Sensitest, a synthetic medium, to detect AMB resistance were analyzed and compared with those obtained with RPMI and antibiotic medium 3 (AM3). The ability to detect AMB resistance with RPMI is not enhanced by using a higher inoculum, glucose supplementation at a final concentration of 20 g/liter, spectrophotometric reading, or 24 h of incubation time. Testing using AM3 and an inoculum of 10(3) CFU/ml detects resistance. Identification of resistant isolates is not improved by glucose supplementation, changes in reading method, or changes in incubation time. However, the use of AM3 as assay medium and an inoculum of 10(5) CFU/ml did not allow detection of AMB resistance. Testing using Iso-Sensitest medium appears to be similar to AM3 in detecting resistance. The most pronounced discrimination is achieved by testing in Iso-Sensitest supplemented with glucose and spectrophotometric reading after 24 h of incubation. The reproducibility of MIC testing was greatest for Iso-Sensitest-based procedures. Use of Iso-Sensitest produces both highly reproducible MICs and reliable identification of AMB-resistant Candida isolates.
Collapse
Affiliation(s)
- M Cuenca-Estrella
- Centro Nacional de Microbiologia, Instituto de Salud Carlos III, Madrid, Spain.
| | | | | | | |
Collapse
|
18
|
Lee SC, Fung CP, Lee N, See LC, Huang JS, Tsai CJ, Chen KS, Shieh WB. Fluconazole disk diffusion test with methylene blue- and glucose-enriched Mueller-Hinton agar for determining susceptibility of Candida species. J Clin Microbiol 2001; 39:1615-7. [PMID: 11283099 PMCID: PMC87982 DOI: 10.1128/jcm.39.4.1615-1617.2001] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A 25-microg fluconazole disk diffusion test using a Mueller-Hinton agar plate containing 2% glucose and 5 microg of methylene blue/ml (GM-MH) was compared to the macrodilution reference method for 210 Candida species. The GM-MH agar plate was read at 24 h. The predictive values of disks with susceptible, intermediate, and resistant results on the GM-MH agar plate at 24 h were 97.1, 56.3, and 76.5%, respectively.
Collapse
Affiliation(s)
- S C Lee
- Division of Infectious Diseases, Chang Gung Memorial Hospital, Keelung, Taipei, Taiwan, Republic of China.
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Cuenca-Estrella M, Díaz-Guerra TM, Mellado E, Rodríguez-Tudela JL. Influence of glucose supplementation and inoculum size on growth kinetics and antifungal susceptibility testing of Candida spp. J Clin Microbiol 2001; 39:525-32. [PMID: 11158101 PMCID: PMC87770 DOI: 10.1128/jcm.39.2.525-532.2001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The influences of inoculum size and glucose supplementation on the growth kinetics of 60 Candida spp. clinical isolates (Candida albicans, Candida tropicalis, Candida parapsilosis, Candida glabrata, Candida krusei, and Candida lusitaniae [10 isolates each]) are assessed. The combined influence of growth and reading method (visual or spectrophotometric) on the determination of the MICs of amphotericin B, flucytosine, fluconazole, itraconazole, ketoconazole, and voriconazole is also analyzed, and the MICs are compared with those determined by the National Committee for Clinical Laboratory Standards standard microdilution method (NCCLS document M27-A). Glucose supplementation and inoculum size had a significant influence on the growth cycles of these yeasts, and a statistically significant denser growth (optical density at 540 nm) was seen for both incubation periods, 24 and 48 h (P < 0.01). A longer exponential phase and shorter lag phase were also observed. The A540 values at 24 h of incubation with medium containing glucose and an inoculum of 10(5) CFU/ml were >0.4 U for all species, with the exception of that for C. parapsilosis (A540 = 0.26 +/- 0.025). The MICs at 24 h determined by testing with 2% glucose and an inoculum of 10(5) CFU/ml showed the strongest agreement (96.83%) with MICs determined by the reference method. MICs were not falsely elevated, and good correlation indexes were obtained. The reproducibility of results with this medium-inoculum combination was high (intraclass correlation coefficient, 0.955). The best agreement and reproducibility of results for spectrophotometric readings were achieved with endpoints of 50% growth inhibition for flucytosine and azoles and 95% for amphotericin B. Supplementation of test media with glucose and an inoculum size of 10(5) CFU/ml yielded a reproducible technique that shows elevated agreement with the reference procedures and a shorter incubation period for obtaining reliable MIC determinations. The spectrophotometric method offers an advantage over the visual method by providing a more objective and automated MIC determination.
Collapse
Affiliation(s)
- M Cuenca-Estrella
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, 28220 Majadahonda, Madrid, Spain.
| | | | | | | |
Collapse
|
20
|
Rodríguez-Tudela JL, Martín-Díez F, Cuenca-Estrella M, Rodero L, Carpintero Y, Gorgojo B. Influence of shaking on antifungal susceptibility testing of Cryptococcus neoformans: a comparison of the NCCLS standard M27A medium, buffered yeast nitrogen base, and RPMI-2% glucose. Antimicrob Agents Chemother 2000; 44:400-4. [PMID: 10639369 PMCID: PMC89690 DOI: 10.1128/aac.44.2.400-404.2000] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cryptococcus neoformans is a nonfermentative yeast that requires oxygen for growth. The shaking of culture media achieves good oxygenation, promoting the growth of cryptococci. In this study, three test media (RPMI 1640, RPMI 1640-2% glucose, and buffered yeast nitrogen base ¿BYNB) recommended in the National Committee for Clinical Laboratory Standards M27A standard were examined. Growth abilities and minimum inhibitory concentrations (MICs) in microplates incubated at 35 degrees C for 48 h were determined. The results indicated that shaking and an inoculum size of 10(5) CFU/ml yielded optimal growth of this yeast. Compared to RPMI 1640, supplementation of RPMI 1640 with 2% glucose did not significantly improve growth of C. neoformans and resulted in an 8.7-h delay of exponential growth. Cryptococcal growth in RPMI 1640 at 24 h was notably better than that in RPMI-2% glucose, although by 48 h the growths were comparable. The MIC range of amphotericin B observed for the C. neoformans strains grown in RPMI 1640 with or without glucose was too narrow to allow the separation of susceptible and resistant strains based on clinical outcome. The widest ranges of MICs of flucytosine and fluconazole were obtained with BYNB. This work demonstrates the need for a new antifungal susceptibility test for C. neoformans.
Collapse
Affiliation(s)
- J L Rodríguez-Tudela
- Servicio de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Ctra. Majadahonda-Pozuelo km.2, 28220 Majadahonda, Spain
| | | | | | | | | | | |
Collapse
|
21
|
Lozano-Chiu M, Arikan S, Paetznick VL, Anaissie EJ, Rex JH. Optimizing voriconazole susceptibility testing of Candida: effects of incubation time, endpoint rule, species of Candida, and level of fluconazole susceptibility. J Clin Microbiol 1999; 37:2755-9. [PMID: 10449447 PMCID: PMC85370 DOI: 10.1128/jcm.37.9.2755-2759.1999] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Voriconazole is a new triazole antifungal agent that has potent activity against many isolates of Candida, including Candida krusei and Candida glabrata. In this work, we studied the impact of glucose supplementation, incubation time, agitation of the plates prior to reading, endpoint determination rule, visual versus spectrophotometric reading, Candida species, and fluconazole MIC on the MIC of voriconazole for Candida isolates tested by using the microdilution format assay of the National Committee for Clinical Laboratory Standards (NCCLS) M27-A antifungal susceptibility testing methodology. For both voriconazole and fluconazole, a spectrophotometric endpoint of 50% reduction in turbidity relative to the growth control correlated most closely with the NCCLS-defined visual endpoint of "prominent decrease in turbidity." Correlation was generally better after 24 h of incubation than after 48 h. Supplementation of the medium to contain 20 g of glucose/liter did not alter the MIC significantly but did enhance growth and simplify visual readings. All Candida species appeared potentially susceptible to voriconazole, including isolates of C. krusei. For some isolates for which fluconazole MICs were markedly elevated voriconazole MICs were also elevated, but the clinical significance of these observations remains to be determined.
Collapse
Affiliation(s)
- M Lozano-Chiu
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas 77030, USA
| | | | | | | | | |
Collapse
|
22
|
Ramos G, Cuenca-Estrella M, Monzón A, Rodríguez-Tudela JL. In-vitro comparative activity of UR-9825, itraconazole and fluconazole against clinical isolates of Candida spp. J Antimicrob Chemother 1999; 44:283-6. [PMID: 10473237 DOI: 10.1093/jac/44.2.283] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
UR-9825 is a new broad-spectrum triazole antifungal agent with a good pharmacokinetic profile and excellent bioavailability. It shows high in-vitro activity and efficacy in models of systemic candidosis in rats and rabbits, comparing favourably with fluconazole. The purpose of this study was to evaluate the in-vitro activity of UR-9825 and to compare it with that of fluconazole and itraconazole against 283 clinical isolates of Candida spp. UR-9825 was more potent against Candida spp. than both fluconazole and itraconazole, even against some Candida albicans and Candida krusei isolates with decreased susceptibility to fluconazole (MIC 16 mg/L).
Collapse
Affiliation(s)
- G Ramos
- Unidad de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, Madrid, Spain
| | | | | | | |
Collapse
|
23
|
Cantón E, Pemán J, Carrillo-Muñoz A, Orero A, Ubeda P, Viudes A, Gobernado M. Fluconazole susceptibilities of bloodstream Candida sp. isolates as determined by National Committee for Clinical Laboratory Standards method M27-A and two other methods. J Clin Microbiol 1999; 37:2197-200. [PMID: 10364585 PMCID: PMC85117 DOI: 10.1128/jcm.37.7.2197-2200.1999] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/1998] [Accepted: 03/17/1999] [Indexed: 11/20/2022] Open
Abstract
The in vitro activity of fluconazole against 143 Candida spp. obtained from the bloodstreams of 143 hospitalized patients from 1995 to 1997 was studied. Susceptibility tests were carried out by two macrodilution methods, the M27-A and a modified M27-A method (0. 165 M, pH 7/morpholinepropanesulfonic acid-buffered RPMI 1640 medium supplemented with 20 g of D-dextrose per liter), and by the agar diffusion method (with 15-microg fluconazole [Neo-Sensitab] tablets). With 2 microg of fluconazole per ml, 96.92% of 65 C. albicans isolates, 86.2% of 58 C. parapsilosis isolates 7 of 8 C. tropicalis isolates, and 1 of 6 C. glabrata isolates were inhibited. Only one strain of C. albicans and one strain of C. tropicalis were resistant. The agreement between the two macrodilution methods was greater than 90% within +/-2 log2 dilutions for all strains except C. glabrata (83.3%) and C. tropicalis (87.5%). Generally, MICs were 1 log2 dilution lower in glucose-supplemented RPMI 1640 medium. No correlation between zone sizes and MICs was found. All strains susceptible by the diffusion test were susceptible by the dilution method, but the converse was not necessarily true. Interestingly, inhibition zones were smaller for C. albicans, for which the geometric mean MIC was 0.29 microg/ml and the mean inhibition zone diameter was 25.7 mm, while for C. parapsilosis the geometric mean MIC was 0.96 microg/ml and the mean inhibition zone diameter was 31. 52 mm. In conclusion, the two macrodilution methods give similar results. The modified M27-A method with 2% dextrose has the advantage of shortening the incubation time and simplifying the endpoint determination.
Collapse
Affiliation(s)
- E Cantón
- Unidad de Bacteriología Experimental-Centro de Investigación, Hospital Universitario La Fe, 46009 Valencia, Spain.
| | | | | | | | | | | | | |
Collapse
|
24
|
Torres-Rodríguez JM, Mendez R, López-Jodra O, Morera Y, Espasa M, Jimenez T, Lagunas C. In vitro susceptibilities of clinical yeast isolates to the new antifungal eberconazole compared with their susceptibilities to clotrimazole and ketoconazole. Antimicrob Agents Chemother 1999; 43:1258-9. [PMID: 10223946 PMCID: PMC89253 DOI: 10.1128/aac.43.5.1258] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The antifungal activity of eberconazole, a new imidazole derivative, against 124 clinical isolates of Candida comprising eight different species and to 34 isolates of Cryptococcus neoformans was compared to those of clotrimazole and ketoconazole. MICs of eberconazole, determined by the National Committee for Clinical Laboratory Standards standardized microbroth method, were equal to or lower than those of other azoles, especially for Candida krusei and Candida glabrata, which are usually resistant to triazoles.
Collapse
Affiliation(s)
- J M Torres-Rodríguez
- Experimental and Clinical Mycology Research Group (GREMEC), IMIM, Autonomous University of Barcelona, Barcelona, Spain.
| | | | | | | | | | | | | |
Collapse
|
25
|
Cuenca-Estrella M, Ruiz-Díez B, Martínez-Suárez JV, Monzón A, Rodríguez-Tudela JL. Comparative in-vitro activity of voriconazole (UK-109,496) and six other antifungal agents against clinical isolates of Scedosporium prolificans and Scedosporium apiospermum. J Antimicrob Chemother 1999; 43:149-51. [PMID: 10381115 DOI: 10.1093/jac/43.1.149] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We report the in-vitro susceptibility of 27 clinical isolates of Scedosporium apiospermum and 43 of Scedosporium prolificans. S. apiospermum was resistant to fluconazole and flucytosine, with variable susceptibility to amphotericin B, itraconazole, ketoconazole and susceptible to miconazole. Voriconazole was much more active than fluconazole and flucytosine, more active than amphotericin B, itraconazole and ketoconazole and was as active as miconazole against S. apiospermum isolates. Voriconazole and the other six antifungal agents showed low activity against S. prolificans isolates.
Collapse
Affiliation(s)
- M Cuenca-Estrella
- Unidad de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda (Madrid), Spain
| | | | | | | | | |
Collapse
|
26
|
Nguyen MH, Yu CY. Influence of incubation time, inoculum size, and glucose concentrations on spectrophotometric endpoint determinations for amphotericin B, fluconazole, and itraconazole. J Clin Microbiol 1999; 37:141-5. [PMID: 9854079 PMCID: PMC84190 DOI: 10.1128/jcm.37.1.141-145.1999] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We addressed the influence of the incubation time (24 h versus 48 h), starting inoculum size (standard inoculum size, approximately 10(3) CFU/ml, versus large inoculum size, approximately 10(4) CFU/ml), and supplementation with 2% glucose of RPMI 1640 medium on the spectrophotometric determination of the MICs of amphotericin B, fluconazole, and itraconazole. We compared the MICs determined spectrophotometrically with those determined by the standard broth macrodilution method (National Committee for Clinical Laboratory Standards approved guideline M27-A). The agreement between the results of the spectrophotometric and standard methods for amphotericin B testing was 100%; this agreement was independent of the inoculum size and incubation time. On the other hand, the agreement for the results for fluconazole testing and itraconazole testing was dependent on the inoculum size and incubation time. With large inoculum size, excellent agreement can be achieved at 24 h. With standard inoculum size, acceptable agreement can be achieved only at 48 h. In contrast to previous observations, the addition of 2% glucose did not have any significant impact on the growth density at 24 h, nor did it improve the agreement with the standard method. Furthermore, supplemental glucose might falsely elevate the MIC at 48 h.
Collapse
Affiliation(s)
- M H Nguyen
- Department of Medicine, University of Florida College of Medicine, and Gainesville VA Medical Center, Gainesville, Florida 32610, USA.
| | | |
Collapse
|
27
|
Herreros E, Martinez CM, Almela MJ, Marriott MS, De Las Heras FG, Gargallo-Viola D. Sordarins: in vitro activities of new antifungal derivatives against pathogenic yeasts, Pneumocystis carinii, and filamentous fungi. Antimicrob Agents Chemother 1998; 42:2863-9. [PMID: 9797217 PMCID: PMC105957 DOI: 10.1128/aac.42.11.2863] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
GM 193663, GM 211676, GM 222712, and GM 237354 are new semisynthetic derivatives of the sordarin class. The in vitro antifungal activities of GM 193663, GM 211676, GM 222712, and GM 237354 against 111 clinical yeast isolates of Candida albicans, Candida kefyr, Candida glabrata, Candida parapsilosis, Candida krusei, and Cryptococcus neoformans were compared. The in vitro activities of some of these compounds against Pneumocystis carinii, 20 isolates each of Aspergillus fumigatus and Aspergillus flavus, and 30 isolates of emerging less-common mold pathogens and dermatophytes were also compared. The MICs of GM 193663, GM 211676, GM 222712, and GM 237354 at which 90% of the isolates were inhibited (MIC90s) were 0.03, 0.03, 0.004, and 0.015 microg/ml, respectively, for C. albicans, including strains with decreased susceptibility to fluconazole; 0.5, 0.5, 0.06, and 0.12 microg/ml, respectively, for C. tropicalis; and 0.004, 0.015, 0.008, and 0.03 microg/ml, respectively, for C. kefyr. GM 222712 and GM 237354 were the most active compounds against C. glabrata, C. parapsilosis, and Cryptococcus neoformans. Against C. glabrata and C. parapsilosis, the MIC90s of GM 222712 and GM 237354 were 0.5 and 4 microg/ml and 1 and 16 microg/ml, respectively. The MIC90s of GM 222712 and GM 237354 against Cryptococcus neoformans were 0.5 and 0.25 microg/ml, respectively. GM 193663, GM 211676, GM 222712, and GM 237354 were extremely active against P. carinii. The efficacies of sordarin derivatives against this organism were determined by measuring the inhibition of the uptake and incorporation of radiolabelled methionine into newly synthesized proteins. All compounds tested showed 50% inhibitory concentrations of <0.008 microg/ml. Against A. flavus and A. fumigatus, the MIC90s of GM 222712 and GM 237354 were 1 and 32 microg/ml and 32 and >64 microg/ml, respectively. In addition, GM 237354 was tested against the most important emerging fungal pathogens which affect immunocompromised patients. Cladosporium carrioni, Pseudallescheria boydii, and the yeast-like fungi Blastoschizomyces capitatus and Geotrichum clavatum were the most susceptible of the fungi to GM 237354, with MICs ranging from </=0.25 to 2 microg/ml. The MICs of GM 237354 against Trichosporon beigelii and the zygomycetes Absidia corymbifera, Cunninghamella bertholletiae, and Rhizopus arrhizus ranged from </=0.25 to 8 microg/ml. Against dermatophytes, GM 237354 MICs were >/=2 microg/ml. In summary, we concluded that some sordarin derivatives, such as GM 222712 and GM 237354, showed excellent in vitro activities against a wide range of pathogenic fungi, including Candida spp., Cryptococcus neoformans, P. carinii, and some filamentous fungi and emerging invasive fungal pathogens.
Collapse
Affiliation(s)
- E Herreros
- Glaxo Wellcome S.A., 28760 Tres Cantos, Madrid, Spain
| | | | | | | | | | | |
Collapse
|
28
|
Lozano-Chiu M, Paetznick VL, Ghannoum MA, Rex JH. Detection of resistance to amphotericin B among Cryptococcus neoformans clinical isolates: performances of three different media assessed by using E-test and National Committee for Clinical Laboratory Standards M27-A methodologies. J Clin Microbiol 1998; 36:2817-22. [PMID: 9738026 PMCID: PMC105070 DOI: 10.1128/jcm.36.10.2817-2822.1998] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Although reliable detection of resistance in vitro is critical to the overall performance of any susceptibility testing method, the recently released National Committee for Clinical Laboratory Standards M27-A methodology for susceptibility testing of yeasts discriminates poorly between resistant and susceptible isolates of Candida spp. We have previously shown that both substitution of antibiotic medium 3 for RPMI 1640 medium in the microdilution variant of the M27-A method and use of the E-test agar diffusion methodology permit detection of amphotericin B-resistant Candida isolates. To determine the relevance of these observations to Cryptococcus neoformans, we have evaluated the performances of both the M27-A and the E-test methodologies with this yeast using three different media (RPMI 1640 medium, antibiotic medium 3, and yeast nitrogen base). As with Candida, we found that only antibiotic medium 3 permitted consistent detection of resistant isolates when testing was performed in broth by the M27-A method. When testing was performed by the E-test agar diffusion method, both RPMI 1640 medium and antibiotic medium 3 agar permitted ready detection of the resistant isolates. Reading of the results after 48 h of incubation was required for testing in broth by the M27-A method, while the MIC could be determined after either 48 or 72 h when the agar diffusion method was used.
Collapse
Affiliation(s)
- M Lozano-Chiu
- Division of Infectious Diseases, Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston, Texas, USA.
| | | | | | | |
Collapse
|
29
|
Rex JH, Nelson PW, Paetznick VL, Lozano-Chiu M, Espinel-Ingroff A, Anaissie EJ. Optimizing the correlation between results of testing in vitro and therapeutic outcome in vivo for fluconazole by testing critical isolates in a murine model of invasive candidiasis. Antimicrob Agents Chemother 1998; 42:129-34. [PMID: 9449272 PMCID: PMC105467 DOI: 10.1128/aac.42.1.129] [Citation(s) in RCA: 128] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The trailing growth phenomenon seen when determining the susceptibilities of Candida isolates to the azole antifungal agents makes consistent endpoint determination difficult, and the M27-A method of the National Committee for Clinical Laboratory Standards addresses this problem by requiring an 80% reduction in growth after 48 h of incubation. For some isolates, however, minor variations of this endpoint criterion can produce up to 128-fold variations in the resulting MIC. To investigate the significance of this effect, isolates of Candida that exhibited various forms of trailing growth when tested against fluconazole were identified. The isolates were examined in a murine model of invasive candidiasis and were ranked by their relative response to fluconazole by using both improvement in survival and reduction in fungal burden in the kidney. The resulting rank order of in vivo response did not match the MICs obtained by using the M27-A criterion, and these MICs significantly overestimated the resistance of three of the six isolates tested. However, if the MIC was determined after 24 h of incubation and the endpoint required a less restrictive 50% reduction in growth, MICs which better matched the in vivo response pattern could be obtained. Minor variations in the M27-A endpoint criterion are thus required to optimize the in vitro-in vivo correlation for isolates that demonstrate significant trailing growth when tested against fluconazole.
Collapse
Affiliation(s)
- J H Rex
- Department of Internal Medicine, Center for the Study of Emerging and Reemerging Pathogens, University of Texas Medical School, Houston 77030, USA.
| | | | | | | | | | | |
Collapse
|
30
|
Ruiz-Diez B, Martinez V, Alvarez M, Rodriguez-Tudela JL, Martinez-Suarez JV. Molecular tracking of Candida albicans in a neonatal intensive care unit: long-term colonizations versus catheter-related infections. J Clin Microbiol 1997; 35:3032-6. [PMID: 9399489 PMCID: PMC230117 DOI: 10.1128/jcm.35.12.3032-3036.1997] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Nosocomial neonatal candidiasis is a major problem in infants requiring intensive therapy. The subjects of this retrospective study were nine preterm infants admitted to the neonatal intensive care unit of the Hospital Central de Asturias between March 1993 and August 1994. The infants were infected with or colonized by Candida albicans. Five patients developed C. albicans bloodstream infections. A total of 36 isolates (including isolates from catheters and parenteral nutrition) were examined for molecular relatedness by PCR fingerprinting and restriction fragment length polymorphism (RFLP) analysis. The core sequence of phage M13 was used as a single primer in the PCR-based fingerprinting procedure, and RFLP analysis was performed with C. albicans-specific DNA probe 27A. Both techniques were evaluated with a panel of eight C. albicans reference strains, and each technique showed eight different patterns. With the 36 isolates from neonates, each technique enabled us to identify by PCR and RFLP analysis seven and six different patterns, respectively. The combination of these two methods (composite DNA type) identified eight different profiles. A strain with one of these profiles was present in three patients and in their respective catheters. Patients infected with or colonized by this isolate profile were clustered in time. Among the other patients, each patient was infected over time and at multiple anatomic sites with a C. albicans strain with a distinct DNA type. We conclude that C. albicans was most commonly producing long-term colonizations, although horizontal transmission probably due to catheters also occurred.
Collapse
Affiliation(s)
- B Ruiz-Diez
- Unidad de Micología, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | | | | | | | | |
Collapse
|
31
|
Law D, Moore CB, Denning DW. Activity of SCH 56592 compared with those of fluconazole and itraconazole against Candida spp. Antimicrob Agents Chemother 1997; 41:2310-1. [PMID: 9333073 PMCID: PMC164118 DOI: 10.1128/aac.41.10.2310] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The in vitro activity of Schering 56592, a new azole drug, was compared with those of fluconazole and itraconazole against 103 isolates of Candida comprising 10 different species. Schering 56592 was more active than itraconazole and fluconazole, and it was active against many fluconazole-resistant isolates.
Collapse
Affiliation(s)
- D Law
- Department of Microbiology, Hope Hospital, Salford, United Kingdom
| | | | | |
Collapse
|
32
|
|
33
|
Abstract
Resistance of Candida to azoles is an increasing problem. Susceptibility testing of Candida against fluconazole and ketoconazole is now feasible and desirable. Good correlation of resistance in vitro with clinical failure of fluconazole therapy has now been shown in mucosal candidiasis. The relationship, if any, between resistance and clinical failure in the context of invasive candidiasis is not clear at present and additional correlative work needs to be done. Monitoring of resistance trends in Candida is clearly important now.
Collapse
Affiliation(s)
- D W Denning
- Department of Infectious Diseases and Tropical Medicine, North Manchester General Hospital, UK
| | | | | |
Collapse
|
34
|
Rodríguez-Tudela JL, Martinez-Suarez JV. Fluconazole and amphotericin B antifungal susceptibility testing by National Committee for Clinical Laboratory Standards broth macrodilution method compared with E-test and semiautomated broth microdilution test. J Clin Microbiol 1997; 35:336-7. [PMID: 8968944 PMCID: PMC229575 DOI: 10.1128/jcm.35.1.336-337.1997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
|
35
|
Espinel-Ingroff A, Bartlett M, Bowden R, Chin NX, Cooper C, Fothergill A, McGinnis MR, Menezes P, Messer SA, Nelson PW, Odds FC, Pasarell L, Peter J, Pfaller MA, Rex JH, Rinaldi MG, Shankland GS, Walsh TJ, Weitzman I. Multicenter evaluation of proposed standardized procedure for antifungal susceptibility testing of filamentous fungi. J Clin Microbiol 1997; 35:139-43. [PMID: 8968895 PMCID: PMC229526 DOI: 10.1128/jcm.35.1.139-143.1997] [Citation(s) in RCA: 164] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
A multicenter study was conducted to expand the generation and analysis of data that supports the proposal of a reference method for the antifungal susceptibility testing of filamentous fungi. Broth microdilution MICs of amphotericin B and itraconazole were determined in 11 centers against 30 coded duplicate pairs of Aspergillus spp., Fusarium spp., Pseudallescheria boydii, and Rhizopus arrhizus. The effect of inoculum density (approximately 10(3) and 10(4) CFU/ml), incubation time (24, 48, and 72 h), and procedure of MIC determination (conventional and colorimetric [Alamar Blue] evaluation of growth inhibition) on intra- and interlaboratory agreement was analyzed. Based on intra- (97 to 100%) and interlaboratory (94 to 95%) agreement for both drugs, the overall optimal testing conditions identified were determination of colorimetric MICs after 48 to 72 h of incubation with an inoculum density of approximately 10(4) CFU/ml. These testing conditions are proposed as guidelines for a reference broth microdilution method.
Collapse
Affiliation(s)
- A Espinel-Ingroff
- Medical College of Virginia/Virginia Commonwealth University, Richmond 23298-0049, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
36
|
Anaissie EJ, Paetznick VL, Ensign LG, Espinel-Ingroff A, Galgiani JN, Hitchcock CA, LaRocco M, Patterson T, Pfaller MA, Rex JH, Rinaldi MG. Microdilution antifungal susceptibility testing of Candida albicans and Cryptococcus neoformans with and without agitation: an eight-center collaborative study. Antimicrob Agents Chemother 1996; 40:2387-91. [PMID: 8891149 PMCID: PMC163539 DOI: 10.1128/aac.40.10.2387] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The growth patterns observed in the trailing wells when fluconazole is being tested may give rise to readings that suggest resistance or increased MICs for known susceptible strains. We conducted a multicenter study to evaluate the intralaboratory and interlaboratory reproducibilities of a method that uses agitation to disperse these types of growth. Ten strains of Candida albicans and five strains of Cryptococcus neoformans were tested against fluconazole, flucytosine, and amphotericin B by using a microdilution adaptation of the proposed reference method of the National Committee for Clinical Laboratory Standards for yeasts (M27-T). The endpoint criterion used before agitation was consistent with the M27-T recommendation, while a criterion of 50% or more reduction of growth compared with the control was used after agitation. The results of this study showed that use of agitation and the modified endpoint criterion both improved intralaboratory and inter-laboratory agreement and increased the frequency of interpretable MICs. The MICs obtained by this method were comparable to those obtained by the broth macrodilution M27-T method. Like M27-T, this method was not able to definitely distinguish amphotericin B-susceptible from -resistant strains, although the MICs for the resistant strains were consistently higher than those for the susceptible ones. The findings imply that agitation should be seriously considered when antifungal agents, particularly fluconazole, are tested in a microdilution format.
Collapse
Affiliation(s)
- E J Anaissie
- Infectious Disease Section, University of Texas M. D. Anderson Cancer Center, Houston 77030, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Barry AL, Brown SD. Fluconazole disk diffusion procedure for determining susceptibility of Candida species. J Clin Microbiol 1996; 34:2154-7. [PMID: 8862576 PMCID: PMC229208 DOI: 10.1128/jcm.34.9.2154-2157.1996] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A simple disk diffusion test was defined for quick determination of the susceptibility of Candida species to fluconazole. The standard macrotube dilution reference method, the fluconazole E test, and a 25-microgram fluconazole disk test were all performed with each of 250 Candida species selected to provide a broad range of fluconazole MICs. All three methods were in excellent agreement. On RPMI 1640-glucose agar, isolates with inhibition zone diameters of > or = 19 mm were all susceptible (MIC, < or = 8.0 micrograms/ml) by the E test and 94% were susceptible by the macrotube method. Strains with smaller zones were either resistant, intermediate (dose-dependent susceptibility), or susceptible by the reference methods. The disk test did not adequately separate fully resistant strains from those with dose-dependent susceptibility: additional quantitative tests are needed for the few strains that are not unequivocally susceptible by the disk method.
Collapse
Affiliation(s)
- A L Barry
- Clinical Microbiology Institute, Tualatin, Oregon 97062, USA
| | | |
Collapse
|
38
|
Rodríguez-Tudela JL, Berenguer J, Martínez-Suárez JV, Sanchez R. Comparison of a spectrophotometric microdilution method with RPMI-2% glucose with the National Committee for Clinical Laboratory Standards reference macrodilution method M27-P for in vitro susceptibility testing of amphotericin B, flucytosine, and fluconazole against Candida albicans. Antimicrob Agents Chemother 1996; 40:1998-2003. [PMID: 8878570 PMCID: PMC163462 DOI: 10.1128/aac.40.9.1998] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The National Committee for Clinical Laboratory Standards has proposed a reference broth macrodilution method for in vitro antifungal susceptibility testing of yeasts (the M27-P method). This method is cumbersome and time-consuming and includes MIC endpoint determination by visual and subjective inspection of growth inhibition after 48 h of incubation. An alternative microdilution procedure was compared with the M27-P method for determination of the amphotericin B, flucytosine, and fluconazole susceptibilities of 8 American Type Culture Collection strains (6 of them were quality control or reference strains) and 50 clinical isolates of candida albicans. This microdilution method uses as culture medium RPMI 1640 supplemented with 18 g of glucose per liter (RPMI-2% glucose). Preparation of drugs, basal medium, and inocula was done by following the recommendations of the National Committee for Clinical Laboratory Standards. The MIC endpoint was calculated objectively from the turbidimetric data read at 24 h. Increased growth of C. albicans in RPMI-2% glucose and its spectrophotometric reading allowed for the rapid (24 h) and objective calculation of MIC endpoints compared with previous microdilution methods with standard RPMI 1640. Nevertheless, good agreement was shown between the M27-P method and this microdilution test. The MICs obtained for the quality control or reference strains by the microdilution method were in the ranges published for those strains. For clinical isolates, the percentages of agreement were 100% for amphotericin B and fluconazole and 98.1% for flucytosine. These data suggest that this microdilution method may serve as a less subjective and more rapid alternative to the M27-P method for antifungal susceptibility testing of yeasts.
Collapse
|
39
|
Dronda F, Alonso-Sanz M, Laguna F, Chaves F, Martínez-Suárez JV, Rodríguez-Tudela JL, González-López A, Valencia E. Mixed oropharyngeal candidiasis due to Candida albicans and non-albicans Candida strains in HIV-infected patients. Eur J Clin Microbiol Infect Dis 1996; 15:446-52. [PMID: 8839637 DOI: 10.1007/bf01691310] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In order to determine the clinical significance of mixed oropharyngeal candidiasis (Candida albicans plus a non-albicans strain of Candida) in patients infected with HIV-1, a retrospective chart review was done in 12 HIV-1-infected patients with a clinical episode of oropharyngeal candidiasis, in whom a mixed culture of Candida albicans (found to be fluconazole-sensitive) plus a non-albicans species of Candida was obtained from their oral cavities. This group was compared with 26 HIV-positive patients (control group) with oropharyngeal candidiasis due to Candida albicans (found to be fluconazole-sensitive). Antifungal susceptibility testing was performed by a broth microdilution test with RPMI-2% glucose. A fungal strain was considered fluconazole-sensitive if its MIC was < 0.5 micrograms/ml. Both the study and control groups had similar clinical and demographic characteristics. All the patients were severely immunocompromised, with a mean CD4+ lymphocyte count of 63/mm3 (95% CI 41-84) and 80/mm3 (95% CI 25-135) in the study and control groups, respectively. In the study group, seven patients had Candida albicans and Candida krusei in their oral cavity, four had Candida albicans and Candida glabrata, and one had Candida albicans and Candida tropicalis. Antifungal therapy consisted of ketoconazole (5 patients in the study group, 14 in the control group) or fluconazole (7 patients in the study group, 12 in the control group); no statistically significant difference in clinical outcome was observed. Fungal strain persistence after therapy was frequently observed in both groups. It is concluded that non-albicans strains of Candida, less sensitive to azole drugs than their Candida albicans counterparts, are not clinically relevant in episodes of mixed oropharyngeal candidiasis in HIV-1-infected patients.
Collapse
Affiliation(s)
- F Dronda
- Unidad de Enfermedades Infecciosas-Microbiología, Hospital General Penitenciario, Madrid, Spain
| | | | | | | | | | | | | | | |
Collapse
|
40
|
Berenguer J, Diaz-Guerra TM, Ruiz-Diez B, Bernaldo de Quiros JC, Rodriguez-Tudela JL, Martinez-Suarez JV. Genetic dissimilarity of two fluconazole-resistant Candida albicans strains causing meningitis and oral candidiasis in the same AIDS patient. J Clin Microbiol 1996; 34:1542-5. [PMID: 8735114 PMCID: PMC229058 DOI: 10.1128/jcm.34.6.1542-1545.1996] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
We describe a patient with AIDS who simultaneously developed Candida meningitis with three positive cerebrospinal fluid cultures and oral candidiasis. This patient also had a history or recurrent episodes of oral candidiasis treated with fluconazole. The patient did not respond to this therapy but was cured with amphotericin B and flucytosine. In vitro susceptibility tests revealed that each infection was caused by fluconazole-resistant Candida albicans isolates. Strain delineation by karyotyping, NotI restriction pattern analysis, hybridization with the specific probe 27A, and PCR fingerprinting with the phage M13 core sequence clearly demonstrated that meningitis and oral thrush were caused by two genetically different isolates.
Collapse
Affiliation(s)
- J Berenguer
- Servicio de Microbiología Clínica y Enfermedades Infecciosas, Hospital General Universitario Gregorio Marañón, Madrid, Spain
| | | | | | | | | | | |
Collapse
|
41
|
Espinel-Ingroff A, Pfaller M, Erwin ME, Jones RN. Interlaboratory evaluation of Etest method for testing antifungal susceptibilities of pathogenic yeasts to five antifungal agents by using Casitone agar and solidified RPMI 1640 medium with 2% glucose. J Clin Microbiol 1996; 34:848-52. [PMID: 8815095 PMCID: PMC228904 DOI: 10.1128/jcm.34.4.848-852.1996] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
An interlaboratory evaluation (two centers) of the Etest method was conducted for testing the antifungal susceptibilities of yeasts. The MICs of amphotericin B, fluconazole, flucytosine, itraconazole, and ketoconazole were determined for 83 isolates of Candida spp., Cryptococcus neoformans, and Torulopsis glabrata. Two buffered (phosphate buffer) culture media were evaluated: solidified RPMI 1640 medium with 2% glucose and Casitone agar. MIC endpoints were determined after both 24 and 48 h of incubation at 35 degrees C. Analysis of 3,420 MICs demonstrated higher interlaboratory agreement (percentage of MIC pairs within a 2-dilution range) with Casitone medium than with RPMI 1640 medium when testing amphotericin B (84 to 90% versus 1 to 4%), itraconazole (87% versus 63 to 74%), and ketoconazole (94 to 96% versus 88 to 90%). In contrast, better interlaboratory reproducibility was determined between fluconazole MIC pairs when RPMI 1640 medium rather than Casitone medium was used (96 to 98% versus 77 to 90%). Comparison of the flucytosine MICs obtained with RPMI 1640 medium revealed greater than 80% reproducibility. The study suggests the potential value of the Etest as a convenient alternative method for testing the susceptibilities of yeasts. It also indicates the need for further optimization of medium formulations and MIC endpoint criteria to improve interlaboratory agreement.
Collapse
Affiliation(s)
- A Espinel-Ingroff
- Medical College of Virginia/Virginia Commonwealth University, Richmond 23298-0049, USA
| | | | | | | |
Collapse
|
42
|
van Eldere J, Joosten L, Verhaeghe V, Surmont I. Fluconazole and amphotericin B antifungal susceptibility testing by National Committee for Clinical Laboratory Standards broth macrodilution method compared with E-test and semiautomated broth microdilution test. J Clin Microbiol 1996; 34:842-7. [PMID: 8815094 PMCID: PMC228903 DOI: 10.1128/jcm.34.4.842-847.1996] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A comparative study of fluconazole and amphotericin B susceptibility testing was performed with 68 clinical Candida species isolates and three test methods. The methods used were an agar diffusion method (E-test) and two broth dilution methods, the National Committee for Clinical Laboratory Standards (NCCLS) reference broth macrodilution method and an in-house-prepared semiautomated broth microdilution method based on the Bioscreen turbidometer. In the microdilution method, growth of the yeasts was measured continuously by the automatic turbidometer (Bioscreen), which permitted precise and objective determination of endpoints. MIC endpoints were read after 24 h for the microdilution method and the E-test. Amphotericin B susceptibility testing with the NCCLS method and the E-test yielded comparable results in 89% of the tests, meaning that the endpoints obtained were identical or differed by no more than 2 twofold dilutions. The NCCLS and broth microdilution tests scored 97% comparable results, and the E-test and the broth microdilution test yielded 90% comparable results. Fluconazole susceptibility testing produced 96% comparable results with the NCCLS test and the E-test, 100% comparable results with the NCCLS and the microdilution methods, and 98.5% comparable results with the microdilution method and the E-test. We conclude that the E-test and the Bioscreen microdilution method are valuable alternatives to the NCCLS reference method for routine susceptibility testing of Candida species with fluconazole and amphotericin B.
Collapse
Affiliation(s)
- J van Eldere
- Rega Institute, Katholieke Universiteit Leuven, Belgium
| | | | | | | |
Collapse
|
43
|
Buchta V, Otcenásek M. Factors affecting the results of a broth microdilution antifungal susceptibility testing in vitro. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1996; 283:375-90. [PMID: 8861876 DOI: 10.1016/s0934-8840(96)80073-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
In experiments involving 10 antifungal drugs and 46 strains of potentially pathogenic fungi, the factors affecting the results of in vitro susceptibility testing were studied. The composition of the test medium, inoculum size, temperature and length of incubation were the most pronounced effects influencing the results of testing in vitro. Minimal inhibitory concentrations (MIC) of the antimycotics tested were lowest in complex media (Brain Heart Infusion, Antibiotic Medium 3, Sabouraud broth) except for 5-fluorocytosine which was most effective in Yeast Nitrogen Base medium. Inoculum sizes of 10(3) to 10(4) cfu* mL(-1) had no marked effect on MIC but starting from a final concentration of 10(5) cfu*mL(-1), an abrupt increase in MIC in azole derivatives and 5-fluorocytosine was observed. There was a direct relationship between the duration of incubation and MIC of fungistatic antimycotics. The influence of the incubation temperature became generally manifest primarily in fungi with retarded growth at elevated temperature (>35 degrees C). In these fungal species, a tendency towards a decrease in MIC with increasing temperature was apparent. The other factors studied (medium pH, buffer, solvent) had no substantial influence on the antifungal activity of the drugs tested.
Collapse
Affiliation(s)
- V Buchta
- Department of Biological and Medical Sciences, Faculty of Pharmacy, Charles University, Hradec Kralove, Czech Republic
| | | |
Collapse
|
44
|
Quereda C, Polanco AM, Giner C, Sánchez-Sousa A, Pereira E, Navas E, Fortún J, Guerrero A, Baquero F. Correlation between in vitro resistance to fluconazole and clinical outcome of oropharyngeal candidiasis in HIV-infected patients. Eur J Clin Microbiol Infect Dis 1996; 15:30-7. [PMID: 8641300 DOI: 10.1007/bf01586182] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Fifty episodes of oropharyngeal candidiasis in HIV-infected patients were analyzed prospectively in order to evaluate the clinical response to fluconazole. The minimum inhibitory concentrations (MICs) of fluconazole for the Candida strains isolated from the pharynx were correlated with the clinical response. Treatment with fluconazole (100 mg/day) was successful in 86% of the cases. A good clinical outcome followed in 97% of the cases when a strain sensitive to fluconazole was isolated. This figure fell to 22% when the strain was resistant to fluconazole (p < 0.001). The rate of post-treatment colonization was high (87%), and selection of non-albicans Candida species occurred in 23% of the cases. In conclusion, fluconazole treatment for oropharyngeal candidiasis of HIV-infected patients was useful in most cases, but less sensitive non-albicans species can be selected. Most treatment failures were associated with increased MICs of fluconazole for the strains isolated before treatment; therefore, susceptibility testing is recommended as an aid in clinical decision-making for the use of the azole group of drugs.
Collapse
Affiliation(s)
- C Quereda
- Department of Microbiology, Ramón y Cajal Hospital, National Institute of Health (INSALUD), Madrid, Spain
| | | | | | | | | | | | | | | | | |
Collapse
|
45
|
Alvarez M, Lopez Ponga B, Rayon C, Garcia Gala J, Roson Porto MC, Gonzalez M, Martinez-Suarez JV, Rodriguez-Tudela JL. Nosocomial outbreak caused by Scedosporium prolificans (inflatum): four fatal cases in leukemic patients. J Clin Microbiol 1995; 33:3290-5. [PMID: 8586719 PMCID: PMC228690 DOI: 10.1128/jcm.33.12.3290-3295.1995] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Four cases of fatal disseminated Scedosporium prolificans (inflatum) infection occurring in neutropenic patients are reported. Because of hospital renovation, the patients were cared for in a temporary hematologic facility. S. prolificans (inflatum) was isolated from blood cultures of these four patients, two of whom underwent full necropsy, and revealed abundant vegetative hyphae and ovoid conida with truncate bases in many organs. In vitro susceptibility testing of fungal strains showed all isolates to be resistant to amphotericin B, flucytosine, miconazole, ketoconazole, fluconazole, and itraconazole, with MICs greater than 16 micrograms/ml. The reported infections, two in each of two rooms, occurred over a period of 1 month, with very similar clinical outcomes. Circumstancial evidence suggested a nosocomial outbreak, but the environmental samples collected from the rooms, corridors, and adjacent areas did not yield S. prolificans (inflatum). Nevertheless, circumstantial evidence suggested a nosocomial outbreak of S. prolificans (inflatum) infection.
Collapse
Affiliation(s)
- M Alvarez
- Servico de Microbiologia, Hospital Central de Asturias, Oviedo, Spain
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Espinel-Ingroff A, Rodríguez-Tudela JL, Martínez-Suárez JV. Comparison of two alternative microdilution procedures with the National Committee for Clinical Laboratory Standards reference macrodilution method M27-P for in vitro testing of fluconazole-resistant and -susceptible isolates of Candida albicans. J Clin Microbiol 1995; 33:3154-8. [PMID: 8586692 PMCID: PMC228663 DOI: 10.1128/jcm.33.12.3154-3158.1995] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The National Committee for Clinical Laboratory Standards has proposed a reference broth macrodilution method for in vitro antifungal susceptibility testing of yeasts (the M27-P method). This method is cumbersome and time-consuming and includes MIC endpoint determination by the visual and subjective inspection of growth inhibition after 48 h of incubation. Two alternative microdilution procedures for MIC endpoint determination, a spectrophotometric MIC endpoint test that evaluates 80% growth inhibition by the drug and a colorimetric method with an oxidation-reduction indicator (Alamar Blue), were compared with the M27-P method for fluconazole susceptibility testing of 45 susceptible and resistant isolates of Candida albicans. The spectrophotometric method was performed with RPMI 1640 medium with 2% glucose, and the other two tests were performed with plain RPMI 1640 medium. All tests were incubated at 35 degrees C. Excellent agreement was demonstrated between the M27-P method and both 24-h microdilution tests (97.7%) as well as between the two microdilution tests (95.5%). Also, there was agreement in the detection in vivo of fluconazole resistance by the three methods. These preliminary data indicate that both microdilution methods may serve as less subjective alternatives to the M27-P method for the determination of fluconazole MIC endpoints.
Collapse
Affiliation(s)
- A Espinel-Ingroff
- Medical College of Virginia, Virginia Commonwealth University, Richmond 23298-0049, USA
| | | | | |
Collapse
|
47
|
Goa KL, Barradell LB. Fluconazole. An update of its pharmacodynamic and pharmacokinetic properties and therapeutic use in major superficial and systemic mycoses in immunocompromised patients. Drugs 1995; 50:658-90. [PMID: 8536553 DOI: 10.2165/00003495-199550040-00007] [Citation(s) in RCA: 151] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fluconazole is a triazole antifungal agent which is now an established part of therapy in patients with immune deficiencies. It is effective against oropharyngeal/oesophageal candidiasis (candidosis) when used orally once daily either as treatment or secondary prophylaxis in patients with AIDS or as treatment or primary prophylaxis in neutropenia associated with cancer therapy. Fluconazole also resolves symptoms in up to 60% of patients with cryptococcal meningitis and AIDS. However, in this infection its efficacy as treatment relative to that of amphotericin B is equivocal, and its major role is as the drug of choice for maintenance therapy following amphotericin B induction. In this regard, fluconazole has been proven superior to amphotericin B and to itraconazole 200 mg/day. Comparisons with other drugs used for the treatment of mucosal candidiasis in patients with AIDS show fluconazole to be superior to nystatin, similar to itraconazole and at least as effective as clotrimazole and ketoconazole; it was more so than the latter azole in 1 study. In patients undergoing chemotherapy or bone marrow transplantation, fluconazole as primary prophylaxis has produced greater clinical benefit than a clotrimazole regimen. The incidence of adverse events appears to be somewhat higher in patients with AIDS compared with HIV-negative cohorts, but the qualitative pattern of events is similar. The most frequent events are gastrointestinal complaints, headache and skin rash: rare exfoliative skin reactions and isolated instances of clinically overt hepatic dysfunction have occurred in patients with AIDS. Issues yet to be clarified include: the use of fluconazole in children with AIDS, in whom results have been promising; its efficacy against other fungal infections encountered in immunocompromised patients; whether the drug influences mortality, as has been suggested by one placebo-controlled trial in patients undergoing bone marrow transplant; and the appropriateness of its potential for use as primary prophylaxis against cryptococcal meningitis in patients with AIDS, where it shows efficacy but there is concern over increasing risk of development of secondary resistance. Notwithstanding these undefined aspects of its clinical profile, fluconazole is now confirmed as an important antifungal drug in the management of fungal infections in patients with immune deficiencies. In patients with AIDS it is the present drug of choice as maintenance therapy against cryptococcal meningitis and is a preferred agent for secondary prophylaxis against candidal infections; it is also a favoured agent for primary prophylaxis in patients at risk because of neutropenia associated with chemotherapy or bone marrow transplantation .
Collapse
Affiliation(s)
- K L Goa
- Adis International Limited, Auckland, New Zealand
| | | |
Collapse
|
48
|
Odds FC, Vranckx L, Woestenborghs F. Antifungal susceptibility testing of yeasts: evaluation of technical variables for test automation. Antimicrob Agents Chemother 1995; 39:2051-60. [PMID: 8540715 PMCID: PMC162880 DOI: 10.1128/aac.39.9.2051] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The technical parameters for antifungal susceptibility testing with Candida species were reexamined to determine the optimal conditions for testing with semiautomated preparations of broth microdilution cultures, automated spectrophotometric readings of the cultures, and dose-response and endpoint determinations by means of a computer spreadsheet. Tests were based on proposed standard method M27P of the National Committee for Clinical Laboratory Standards for antifungal agents. RPMI 1640 broth with extra glucose to a final concentration of 2% gave higher and more reproducible drug-free control readings without affecting susceptibility endpoint readings. An inoculum of 8 x 10(4) yeasts per ml prepared from a carbon-limiting broth culture without further standardization was found to give optimal control readings after 48 h of incubation at 37 degrees C. For flucytosine, fluconazole, itraconazole, and ketoconazole, endpoints based on 50% growth inhibition (50% inhibitory concentration) gave the minimum variation with inoculum size and the fewest endpoint differences with RPMI 1640 medium obtained from two different suppliers. The 50% inhibitory concentration was also the optimal endpoint for fluconazole and ketoconazole susceptibilities in comparison with broth macrodilution MICs determined by the method of the National Committee for Clinical Laboratory Standards. Intralaboratory reproducibility was determined by retrospective analysis of replicate results for isolates retested at random over a 2-year period. This approach showed less favorable reproducibility than has been reported from purpose-designed, prospective antifungal susceptibility studies, but it may better reflect real-life test reproducibility. Susceptibility data for 616 clinical isolates of yeasts, representing 16 Candida and Saccharomyces spp., confirmed the tendency of Candida lusitaniae isolates to show relatively low susceptibilities to amphotericin B, the tendency of Candida krusei isolates to show low flucytosine and fluconazole susceptibilities, and the presence of some isolates in the species Candida albicans, Candida glabrata, and Candida tropicalis with low susceptibilities to azole derivative antifungal agents. The study demonstrates the value of automation and standardization in all stages of yeast susceptibility testing, from plate preparation to data analysis.
Collapse
Affiliation(s)
- F C Odds
- Department of Bacteriology and Mycology, Janssen Research Foundation, Beerse, Belgium
| | | | | |
Collapse
|
49
|
Martinez-Suarez JV, Rodriguez-Tudela JL. Patterns of in vitro activity of itraconazole and imidazole antifungal agents against Candida albicans with decreased susceptibility to fluconazole from Spain. Antimicrob Agents Chemother 1995; 39:1512-6. [PMID: 7492095 PMCID: PMC162772 DOI: 10.1128/aac.39.7.1512] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Two groups of recent clinical isolates of Candida albicans consisting of 101 isolates for which fluconazole MICs were < or = 0.5 microgram/ml (n = 50) and > or = 4.0 micrograms/ml (n = 51), respectively, were compared for their susceptibilities to fluconazole, clotrimazole, miconazole, ketoconazole, and itraconazole. Susceptibility tests were performed by a photometer-read broth microdilution method with an improved RPMI 1640 medium supplemented with 18 g of glucose per liter (RPMI-2% glucose; J. L. Rodríguez-Tudela and J. V. Martínez-Suárez, Antimicrob. Agents Chemother. 38:45-48, 1994). Preparation of drugs, basal medium, and inocula was done by the recommendations of the National Committee for Clinical Laboratory Standards. The MIC endpoint was calculated objectively from the turbidimetric data read at 24 h as the lowest drug concentration at which growth was just equal to or less than 20% of that in the positive control well (MIC 80%). In vitro susceptibility testing separated azole-susceptible strains from the strains with decreased susceptibilities to azoles if wide ranges of concentrations (20 doubling dilutions) were used for ketoconazole, miconazole, and clotrimazole. By comparison with isolates for which fluconazole MICs were < or = 0.5 microgram/ml, those isolates for which fluconazole MICs were > or = 4.0 micrograms/ml were in general less susceptible to other azole drugs, but different patterns of decreased susceptibility were found, including uniform increases in the MICs of all azole derivatives, higher MICs of several azoles but not others, and elevated MICs of fluconazole only. On the other hand, decreased susceptibility to any other azole drug was never found among strains for which MICs of fluconazole were lower.
Collapse
|
50
|
Rex JH, Cooper CR, Merz WG, Galgiani JN, Anaissie EJ. Detection of amphotericin B-resistant Candida isolates in a broth-based system. Antimicrob Agents Chemother 1995; 39:906-9. [PMID: 7785993 PMCID: PMC162651 DOI: 10.1128/aac.39.4.906] [Citation(s) in RCA: 136] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Because of the limited ability of the National Committee for Clinical Laboratory Standards proposed M27P methodology to detect resistance to amphotericin B by Candida isolates, we sought to identify alternative media and pH conditions that could reliably identify resistant isolates. Antibiotic Medium 3 broth (also known as Penassay broth) buffered to pH 5 or pH 7 produced superior results and readily identified a series of resistant isolates.
Collapse
Affiliation(s)
- J H Rex
- Department of Internal Medicine, University of Texas Medical School, Houston, USA
| | | | | | | | | |
Collapse
|