<abstract xmlns="http://www.w3.org/1999/xhtml">

<sec id="j_1905-7415.1001.468_s_001">
<h3>Background</h3>
<p>Broth microdilution (BMD) is a standard assay for susceptibility of Candida to antifungals, but complexity limits its routine application. E-test (ET) and disk diffusion (DD) assays are attractive alternatives because of their simplicity and reproducibility.</p>
</sec>
<sec id="j_1905-7415.1001.468_s_002">
<h3>Objectives</h3>
<p>To determine the correlation between BMD, and ET and DD assay results for Candida isolates.</p>
</sec>
<sec id="j_1905-7415.1001.468_s_003">
<h3>Methods</h3>
<p>We tested 63 Candida isolates for their susceptibility to fluconazole and voriconazole using BMD, ET, and DD, and recorded minimum inhibitory concentrations (MIC) and inhibitory zone diameters (ZD). Spearman correlations were determined and the Clinical and Laboratory Standards Institute recommendations were used to assess major and minor errors in test results.</p>
</sec>
<sec id="j_1905-7415.1001.468_s_004">
<h3>Results</h3>
<p>The isolates included 32 (51%) C. albicans, 14 (22%) C. tropicalis, 12 (19%) C. parapsilosis, 4 (6%) C. glabrata, and 1 (2%) C. guilliermondii. The BMD-MIC and ET-MIC had good correlation for fluconazole (r = 0.94; P &lt; 0.001) and voriconazole (r = 0.95; P &lt; 0.001). The BMD-MIC for both antifungals were significantly correlated with the ZD of the DD assays (r = −0.47; P &lt; 0.001; r = −0.75; P &lt; 0.001, respectively). Agreement between the BMD and the ET and DD results exceeded 90%. No major errors were identified in any comparisons.</p>
</sec>
<sec id="j_1905-7415.1001.468_s_005">
<h3>Conclusions</h3>
<p><italic>C. albicans</italic> were predominant among the isolates and were susceptible to fluconazole and voriconazole. The BMD results were well correlated with ET and DD assay results, and therefore ET and DD assays can be recommended as initial screening tools in resource-limited hospitals because of their relatively low cost.</p>
</sec>
</abstract>

Background
Broth microdilution (BMD) is a standard assay for susceptibility of Candida to antifungals, but complexity limits its routine application. E-test (ET) and disk diffusion (DD) assays are attractive alternatives because of their simplicity and reproducibility.


Objectives
To determine the correlation between BMD, and ET and DD assay results for Candida isolates.


Methods
We tested 63 Candida isolates for their susceptibility to fluconazole and voriconazole using BMD, ET, and DD, and recorded minimum inhibitory concentrations (MIC) and inhibitory zone diameters (ZD). Spearman correlations were determined and the Clinical and Laboratory Standards Institute recommendations were used to assess major and minor errors in test results.


Results
The isolates included 32 (51%) C. albicans, 14 (22%) C. tropicalis, 12 (19%) C. parapsilosis, 4 (6%) C. glabrata, and 1 (2%) C. guilliermondii. The BMD-MIC and ET-MIC had good correlation for fluconazole (r = 0.94; P < 0.001) and voriconazole (r = 0.95; P < 0.001). The BMD-MIC for both antifungals were significantly correlated with the ZD of the DD assays (r = −0.47; P < 0.001; r = −0.75; P < 0.001, respectively). Agreement between the BMD and the ET and DD results exceeded 90%. No major errors were identified in any comparisons.


Conclusions
C. albicans were predominant among the isolates and were susceptible to fluconazole and voriconazole. The BMD results were well correlated with ET and DD assay results, and therefore ET and DD assays can be recommended as initial screening tools in resource-limited hospitals because of their relatively low cost.

Correlation between broth microdilution, E-test and disk diffusion methods for testing antifungal susceptibility of <italic>Candida</italic> species isolated from Thai blood samples

Asian Biomedicine

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Correlation between broth microdilution, E-test and disk diffusion methods for testing antifungal susceptibility of  species isolated from Thai blood samples

Background
Broth microdilution (BMD) is a standard assay for susceptibility of Candida to antifungals, but complexity limits its routine application. E-test...

Antifungal agent	Candida	MIC range (μg/mL)	No. (%) of isolates indicated susceptibility category by CBPs
Antifungal agent	Candida	MIC range (μg/mL)
			S	S-DD	R
Fluconazole	C. albicans (32)	0.06–2	32(100)	0	0
	C. tropic a H s (14)	0.06–64	13(93)	0	1(7)
	C. parapsilosis (12)	0.125–4	12(100)	0	0
	C. glabrata (4)	0.375–4	4(100)	0	0
	C. guilliermondii (1)	1–1	1 (100)	0	0
Voriconazole	C. albicans (32)	0.06–2	29(91)	3(9)	0
	C. tropic a I is (14)	0.03–1	11(79)	2(14)	1(7)
	C. parapsilosis (12)	0.06–1	12(100)	0	0
	C. glabrata (4)	1–4	2(50)	1(25)	1(25)
	C. guilliermondii (1)	0.5–0.5	1 (100)	0	0

Method	Category	Fluconazole by BMD			No. of strains			Total agreement (%)	Voriconazole by BMD			No. of strains			Total agreement (%)

		S	I	R	VME	ME	mE		S	I	R	VME	ME	mE
ET	S	61	0	0	0	0	1	98	54	2	0	0	0	5	92
	I	1	0	0					1	4	2
	R	0	0	1					0	0	0
DD	S	57	0	0	0	1	4	92	55	1	0	0	0	1	98
	I	4	0	0					0	5	0
	R	1	0	1					0	0	2

Correlation between broth microdilution, E-test and disk diffusion methods for testing antifungal susceptibility of Candida species isolated from Thai blood samples

Article Category: Brief communication (Original)

Publié en ligne: 31 janv. 2017

Pages: 75 - 80

DOI: https://doi.org/10.5372/1905-7415.1001.468

Mots clés
Broth microdilution, candidiasis, disk diffusion, E-test

© 2016 Veeravich Jaruvongvanich, Navaporn Worasilchai, Kitravee Kongnatthasate, Suthinee Jaruvongvanich, Wilawan Damkerngsuntorn, Dusita Atikarnbodee, Arsa Thammahong, Sansanee Lerdlitruangsin, Ariya Chindamporn, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Antifungal susceptibilities of 63 Candida isolates.

Errors with the E-test and disk diffusion methods compared with broth microdilutions for fluconazole and voriconazole

Method	Category	Fluconazole by BMD			No. of strains			Total agreement (%)	Voriconazole by BMD			No. of strains			Total agreement (%)

		S	I	R	VME	ME	mE		S	I	R	VME	ME	mE
ET	S	61	0	0	0	0	1	98	54	2	0	0	0	5	92
	I	1	0	0					1	4	2
	R	0	0	1					0	0	0
DD	S	57	0	0	0	1	4	92	55	1	0	0	0	1	98
	I	4	0	0					0	5	0
	R	1	0	1					0	0	2

Method	Category	Fluconazole by BMD			No. of strains			Total agreement (%)	Voriconazole by BMD			No. of strains			Total agreement (%)

		S	I	R	VME	ME	mE		S	I	R	VME	ME	mE
ET	S	61	0	0	0	0	1	98	54	2	0	0	0	5	92
	I	1	0	0					1	4	2
	R	0	0	1					0	0	0
DD	S	57	0	0	0	1	4	92	55	1	0	0	0	1	98
	I	4	0	0					0	5	0
	R	1	0	1					0	0	2

Correlation between broth microdilution, E-test and disk diffusion methods for testing antifungal susceptibility of Candida species isolated from Thai blood samples

Article Category: Brief communication (Original)

Publié en ligne: 31 janv. 2017

Pages: 75 - 80

DOI: https://doi.org/10.5372/1905-7415.1001.468

Mots clésBroth microdilution, candidiasis, disk diffusion, E-test

© 2016 Veeravich Jaruvongvanich, Navaporn Worasilchai, Kitravee Kongnatthasate, Suthinee Jaruvongvanich, Wilawan Damkerngsuntorn, Dusita Atikarnbodee, Arsa Thammahong, Sansanee Lerdlitruangsin, Ariya Chindamporn, published by Sciendo

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License.

Antifungal susceptibilities of 63 Candida isolates.

Errors with the E-test and disk diffusion methods compared with broth microdilutions for fluconazole and voriconazole

Mots clés
Broth microdilution, candidiasis, disk diffusion, E-test

Method	Category	Fluconazole by BMD			No. of strains			Total agreement (%)	Voriconazole by BMD			No. of strains			Total agreement (%)

		S	I	R	VME	ME	mE		S	I	R	VME	ME	mE
ET	S	61	0	0	0	0	1	98	54	2	0	0	0	5	92
	I	1	0	0					1	4	2
	R	0	0	1					0	0	0
DD	S	57	0	0	0	1	4	92	55	1	0	0	0	1	98
	I	4	0	0					0	5	0
	R	1	0	1					0	0	2