Evaluation of disk diffusion method compared to broth microdilution for antifungal susceptibility testing of 3 echinocandins against Aspergillus spp.

2012 ◽  
Vol 73 (1) ◽  
pp. 53-56 ◽  
Author(s):  
Antonia Isabel Martos ◽  
Estrella Martín-Mazuelos ◽  
Ana Romero ◽  
Carmen Serrano ◽  
Trinidad González ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Disk Diffusion Method

scholarly journals Antifungal susceptibility of clinically significant candida species by disk diffusion method

2021 ◽  
Vol 7 (2) ◽  
pp. 77-80
Author(s):  
Ajitha Reddy Edula
Keyword(s):  
Antifungal Agents ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Antifungal Susceptibility Testing ◽  
Susceptibility Test ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Candida Spp ◽  
Disk Diffusion Method ◽  
Antifungal Susceptibility Test

Antifungal susceptibility of candida. To perform antifungal susceptibility testing on candida isolates by disk diffusion method & study its susceptibility pattern. The present study was conducted in the department of Microbiology in a tertiary care hospital in Hyderabad from January 2013 to June 2014, with prior approval of the Institutional Ethics Committee. The present study was designed to perform antifungal susceptibility test on Candida isolates by Disk Diffusion Method and study its susceptibility pattern. 102 Candida isolates were subjected to Antifungal susceptibility testing by Disk diffusion method using Mueller-Hinton Agar + 2% Glucose and 0.5 μg/mL Methylene Blue Dye (GMB) Mediumas per CLSI guidelines. : Antifungal susceptibility test shows that C. albicans is more susceptible to all the antifungal agents tested. Resistance to azole group of drugs was more pronounced in non-albicans candida spp. Voriconazole seemed to be superior to Fluconazole with a better susceptibility in the Fluconazole resistant strains also.Findings of the antifungal susceptibility test suggest that Candida spp., differ in their susceptibility to antifungal agents. Antifungal susceptibility testing of Candida isolates will be helpful in guiding physicians to select the appropriate antifungal drug so that therapeutic failures can be avoided thus decreasing patient morbidity and mortality.

scholarly journals Comparing Etest and Broth Microdilution for Antifungal Susceptibility Testing of the Most-Relevant Pathogenic Molds

2015 ◽  
Vol 53 (10) ◽  
pp. 3176-3181 ◽  
Author(s):  
Frédéric Lamoth ◽  
Barbara D. Alexander
Keyword(s):  
Amphotericin B ◽  
Antifungal Therapy ◽  
Susceptibility Testing ◽  
Antifungal Susceptibility ◽  
Multidrug Resistant ◽  
Antifungal Susceptibility Testing ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Content Type ◽  
Broth Microdilution Method

Invasive mold infections are life-threatening diseases for which appropriate antifungal therapy is crucial. Their epidemiology is evolving, with the emergence of triazole-resistantAspergillusspp. and multidrug-resistant non-Aspergillusmolds. Despite the lack of interpretive criteria, antifungal susceptibility testing of molds may be useful in guiding antifungal therapy. The standard broth microdilution method (BMD) is demanding and requires expertise. We assessed the performance of a commercialized gradient diffusion method (Etest method) as an alternative to BMD. The MICs or minimal effective concentrations (MECs) of amphotericin B, voriconazole, posaconazole, caspofungin, and micafungin were assessed for 290 clinical isolates of the most representative pathogenic molds (154Aspergillusand 136 non-Aspergillusisolates) with the BMD and Etest methods. Essential agreements (EAs) within ±2 dilutions of ≥90% between the two methods were considered acceptable. EAs for amphotericin B and voriconazole were >90% for most potentially susceptible species. For posaconazole, the correlation was acceptable forMucoromycotinabut Etest MIC values were consistently lower forAspergillusspp. (EAs of <90%). Excellent EAs were found for echinocandins with highly susceptible (MECs of <0.015 μg/ml) or intrinsically resistant (MECs of >16 μg/ml) strains. However, MEC determinations lacked consistency between methods for strains exhibiting mid-range MECs for echinocandins. We concluded that the Etest method is an appropriate alternative to BMD for antifungal susceptibility testing of molds under specific circumstances, including testing with amphotericin B or triazoles for non-Aspergillusmolds (MucoromycotinaandFusariumspp.). Additional study of molecularly characterized triazole-resistantAspergillusisolates is required to confirm the ability of the Etest method to detect voriconazole and posaconazole resistance amongAspergillusspp.

scholarly journals Comparison of Agar Diffusion Methodologies for Antimicrobial Susceptibility Testing of Pseudomonas aeruginosa Isolates from Cystic Fibrosis Patients

2000 ◽  
Vol 38 (5) ◽  
pp. 1818-1822 ◽  
Author(s):  
Jane L. Burns ◽  
Lisa Saiman ◽  
Susan Whittier ◽  
Davise Larone ◽  
Jay Krzewinski ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Pseudomonas Aeruginosa ◽  
Susceptibility Testing ◽  
Correlation Coefficients ◽  
Disk Diffusion ◽  
Diffusion Method ◽  
Broth Microdilution ◽  
Disk Diffusion Method ◽  
Agar Diffusion ◽  
Broth Microdilution Method

Pseudomonas aeruginosa is the most common pathogen infecting the lungs of patients with cystic fibrosis (CF). Improved antimicrobial chemotherapy has significantly increased the life expectancy of these patients. However, accurate susceptibility testing of P. aeruginosa isolates from CF sputum may be difficult because the organisms are often mucoid and slow growing. This study of 597 CF isolates of P. aeruginosa examined the correlation of disk diffusion and Etest (AB BIODISK, Solna, Sweden) results with a reference broth microdilution method. The rates of interpretive errors for 12 commonly used antipseudomonal antimicrobials were determined. The disk diffusion method correlated well (zone diameter versus MIC) for all of the agents tested. However, for mucoid isolates, correlation coefficients (r values) for piperacillin, piperacillin-tazobactam, and meropenem were <0.80. The Etest correlation with reference broth microdilution results (MIC versus MIC) was acceptable for all of the agents tested, for both mucoid and nonmucoid isolates. Category interpretation errors were similar for the disk diffusion and Etest methods with 0.4 and 0.1%, respectively, very major errors (false susceptibility) and 1.1 and 2.2% major errors (false resistance). Overall, both agar diffusion methods appear to be broadly acceptable for routine clinical use in susceptibility testing of CF isolates of P. aeruginosa.

scholarly journals Correlation between E-Test, Disk Diffusion, and Microdilution Methods for Antifungal Susceptibility Testing of Fluconazole and Voriconazole

2003 ◽  
Vol 47 (5) ◽  
pp. 1647-1651 ◽  
Author(s):  
Madonna J. Matar ◽  
Luis Ostrosky-Zeichner ◽  
Victor L. Paetznick ◽  
Jose R. Rodriguez ◽  
Enuo Chen ◽  
...  
Keyword(s):  
Susceptibility Testing ◽  
Clinical Laboratory ◽  
Antifungal Susceptibility ◽  
Reference Method ◽  
Antifungal Susceptibility Testing ◽  
Disk Diffusion ◽  
National Committee ◽  
Broth Microdilution ◽  
Microdilution Method ◽  
Test Disk

ABSTRACT The activities of fluconazole and voriconazole against isolates of Candida spp. (n = 400) were tested by the E-test, disk diffusion, and the National Committee for Clinical Laboratory Standards (NCCLS) M27-A2 broth microdilution-based reference methods. More than 96% of isolates found to be susceptible to fluconazole by the reference method were identified as susceptible by the agar-based methods. Lesser degrees of correlation with the reference method were seen for isolates identified as resistant by the agar-based methods. Interpretive categories are not available for voriconazole, but results qualitatively similar to those for fluconazole were seen. The agar-based E-test and disk diffusion methods are reliable alternatives to the NCCLS M27-A2 reference microdilution method for isolates that test susceptible to fluconazole.

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