In Vitro Amphotericin B Susceptibility of Korean Bloodstream Yeast Isolates Assessed by the CLSI Broth Microdilution Method, Etest, and Minimum Fungicidal Concentration Test

Ji Young Park; Jong Hee Shin; Young Uh; Eui Chong Kim; Seung Jung Kee; Soo Hyun Kim; Myung Geun Shin; Soon Pal Suh; Dong Wook Ryang

doi:10.3343/kjlm.2008.28.5.346

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Park, Shin, Uh, Kim, Kee, Kim, Shin, Suh, and Ryang: In Vitro Amphotericin B Susceptibility of Korean Bloodstream Yeast Isolates Assessed by the CLSI Broth Microdilution Method, Etest, and Minimum Fungicidal Concentration Test

Original Article

Korean J Leg Med 2008;28(5):346-352.

Published online: 14 February 2008

DOI: https://doi.org/10.3343/kjlm.2008.28.5.346

In Vitro Amphotericin B Susceptibility of Korean Bloodstream Yeast Isolates Assessed by the CLSI Broth Microdilution Method, Etest, and Minimum Fungicidal Concentration Test

Ji Young Park, M.D.¹, Jong Hee Shin, M.D.¹, Young Uh, M.D.², Eui Chong Kim, M.D.³, Seung Jung Kee, M.D.¹, Soo Hyun Kim, M.D.¹, Myung Geun Shin, M.D.¹, Soon Pal Suh, M.D.¹, Dong Wook Ryang, M.D.¹

¹Department of Laboratory Medicine, Chonnam National University Medical School, Gwangju, Korea

²Department of Laboratory Medicine, Yonsei University Wonju College of Medicine, Wonju, Korea

³Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea

Received 30 July 20086 September 2008 Accepted 8 September 2008

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background

Although amphotericin B (AMB) has a wide spectrum of activity that encompasses the majority of yeast isolates, there have been recent reports suggesting that some yeast isolates exhibit decreased susceptibility to AMB. However, in vitro AMB susceptibility of yeast species isolates from blood cultures in Korea has not been fully surveyed.

Methods

A total of 92 bloodstream yeast isolates from four Korean hospitals, representing 10 Candida species (69 isolates) and 4 non-Candida yeast species (23 isolates) were evaluated. AMB minimum inhibitory concentrations (MICs) were determined by two methods: the CLSI method and Etest. AMB minimum fungicidal concentrations (MFCs) were also determined.

Results

For all 92 yeast isolates, the CLSI method generated a restricted range of MICs (0.125 to 4 μg/mL) with 3.3% exhibiting MICs ≥2 μg/mL, and the corresponding MFC values ranged from 0.25 to 8 μg/mL with 26.1% showing MFCs ≥2 μg/mL. Etest produced the widest distribution of MICs, ranging from 0.03 to 32 μg/mL. High AMB MICs (≥0.38 μg/mL) by Etest was observed in 34.8% of the isolates: Candida krusei (100%), Candida rugosa (100%), Trichosporon asashii (100%), Candida glabrata (82%), and Yarrowia lipolytica (75%). Etest disclosed that all isolates of Candida guilliermondii, Candida lusitaniae, Candida pelliculosa and Kodamaea ohmeri were highly susceptible to AMB (MIC ≤0.19 μg/mL).

Conclusions

Our study showed that Etest may be more useful to discriminate yeast isolates with reduced susceptibility to AMB, and some isolates of less common yeast species from Korea may have decreased AMB susceptibilities.

Keywords: Candida, Amphotericn B, Etest, Yeast, Minimum fungicidal concentration

REFERENCES

1.Ghannoum MA., Rice LB. Antifungal agents: mode of action, mechanisms of resistance, and correlation of these mechanisms with bacterial resistance. Clin Microbiol Rev. 1999. 12:501–17.

2.Clinical and Laboratory Standards Institute. Reference method for broth dilution antifungal susceptibility testing of yeasts. Approved standard M27-A2. Wayne, PA: Clinical and Laboratory Standards Institute;2002.

3.Antoniadou A., Torres HA., Lewis RE., Thornby J., Bodey GP., Tarrand JP, et al. Candidemia in a tertiary care cancer center: in vitro susceptibility and its association with outcome of initial antifungal therapy. Medicine (Baltimore). 2003. 82:309–21.

4.Nguyen MH., Clancy CJ., Yu VL., Yu YC., Morris AJ., Snydman DR, et al. Do in vitro susceptibility data predict the microbiologic response to amphotericin B? Results of a prospective study of patients with Candida fungemia. J Infect Dis. 1998. 177:425–30.

5.Wanger A., Mills K., Nelson PW., Rex JH. Comparison of Etest and National Committee for Clinical Laboratory Standards broth macrodilution method for antifungal susceptibility testing: enhanced ability to detect amphotericin B-resistant Candida isolates. Antimicrob Agents Chemother. 1995. 39:2520–2.

6.Arendrup M., Lundgren B., Jensen IM., Hansen BS., Frimodt-Moller N. Comparison of Etest and a tablet diffusion test with the NCCLS broth microdilution method for fluconazole and amphotericin B susceptibility testing of Candida isolates. J Antimicob Chemother. 2001. 47:521–6.

7.Clancy CJ., Nguyen MH. Correlation between in vitro susceptibility determined by E test and response to therapy with amphotericin B: results from a multicenter prospective study of candidemia. Antimicrob Agents Chemother. 1999. 43:1289–90.

8.Peyron F., Favel A., Michel-Nguyen A., Gilly M., Regli P., Bolmstrom A. Improved detection of amphotericin B-resistant isolates of Candida lusitaniae by Etest. J Clin Microbiol. 2001. 39:339–42.

9.Pappas PG., Rex JH., Sobel JD., Filler SG., Dismukes WE., Walsh TJ, et al. Guidelines for treatment of candidiasis. Clin Infect Dis. 2004. 38:161–89.

10.Park BJ., Arthington-Skaggs BA., Hajjeh RA., Iqbal N., Ciblak MA., Lee-Yang W, et al. Evaluation of amphotericin B interpretive breakpoints for Candida bloodstream isolates by correlation with therapeutic outcome. Antimicrob Agents Chemother. 2006. 50:1287–92.

11.Pfaller MA., Diekema DJ. Rare and emerging opportunistic fungal pathogens: concern for resistance beyond Candida albicans and Aspergillus fumigatus. J Clin Microbiol. 2004. 42:4419–31.

12.Kim M., Lim WH., Shin JH., Suh SP., Yang DW. E-test for antifungal susceptibility testing of Candida species. Korean J Clin Pathol. 1999. 19:78–85. (김민, 임우현, 신종희, 서순팔, 양동욱. E-test를이용한 Candida species의항진균제감수성검사. 대한임상병리학회지 1999;19: 78-85.).

13.Pfaller MA., Messer SA., Bolmstrom A. Evaluation of Etest for determining in vitro susceptibility of yeast isolates to amphotericin B. Diagn Microbiol Infect Dis. 1998. 32:223–7.

14.Johnson EM., Ojwang JO., Szekely A., Wallace TL., Warnock DW. Comparison of in vitro antifungal activities of free and liposome-encapsulated nystatin with those of four amphotericin B formulations. Antimicrob Agents Chemother. 1998. 42:1412–6.

15.Canton E., Peman J., Viudes A., Quindos G., Gobernado M., Espinel-Ingroff A. Minimum fungicidal concentrations of amphotericin B for bloodstream Candida species. Diagn Microbiol Infect Dis. 2003. 45:203–6.

16.Arikan S., Hascelik G. Comparison of NCCLS microdilution method and Etest in antifungal susceptibility testing of clinical Trichosporon asashii isolates. Diagn Microbiol Infect Dis. 2002. 43:107–11.

17.Koc AN., Gokahmetoglu S., Oguzkaya M. Comparison of E-test with the broth microdilution method in susceptibility testing of yeast isolates against four antifungals. Mycoses. 2000. 43:293–7.

18.Lee JS., Shin JH., Kim MN., Jung SI., Park KH., Cho D, et al. Kodamaea ohmeri isolates from patients in a university hospital: identification, antifungal susceptibility, and pulsed-field gel electrophoresis analysis. J Clin Microbiol. 2007. 45:1005–10.

19.Belet N., Ciftci E., Ince E., Dalgic N., Oncel S., Guriz H, et al. Caspofungin treatment in two infants with persistent fungaemia due to Candida lipolytica. Scand J Infect Dis. 2006. 38:559–62.

20.Rodriguez-Tudela JL., Diaz-Guerra TM., Mellado E., Cano V., Tapia C., Perkins A, et al. Susceptibility patterns and molecular identification of Trichosporon species. Antimicrob Agents Chemother. 2005. 49:4026–34.

Table 1.

Amphotericin B minimum inhibitory concentration by the CLSI method and Etest, and minimuml fungicidal concentration for 92 bloodstream yeast isolates

Species (N tested)	Methods	N of isolates at MIC or MFC (μg/mL) of^∗															% agreement^†
Species (N tested)	Methods	≤0.03	0.06	0.12	0.19	0.25	0.38	0.5	0.75	1	1.5	2	4	8	16	≥32	% agreement^†
C. albicans (10)	CLSI-MIC				-	10	-		-		-
	MFC				-		-	6	-	4	-						100
	Etest				2	7		1
C. glabrata (11)	CLSI-MIC				-	10	-	1	-		-
	MFC				-		-	2	-	8	-	1					100
	Etest				1	1	4	4	1
C. tropicalis (10)	CLSI-MIC				-	6	-	4	-		-
	MFC				-		-	5	-	3	-	2					100
	Etest			3	3	3		1
C. parapsilosis (10)	CLSI-MIC				-	1	-	8	-	1	-
	MFC				-		-	1	-	7	-	1	1				90.9
	Etest	1	3	1	1	2		1				1
C. krusei (9)	CLSI-MIC				-		-	5	-	4	-
	MFC				-		-		-		-	8	1				100
	Etest						1	1	5	2
C. guilliermondii (9)	CLSI-MIC			6	-	2	-	1	-		-
	MFC				-	1	-	8	-		-						100
	Etest	2	2	4	1
C. famata (3)	CLSI-MIC			1	-	1	-	1	-		-
	MFC				-		-	1	-	2	-						100
	Etest			1	1		1
C. lusitaniae (3)	CLSI-MIC	1	-	2	-		-		-
	MFC		-	1	-	1	-	1	-								100
	Etest	2		1
C. rugosa (2)	CLSI-MIC				-		-	2	-		-
	MFC				-		-		-	1	-	1					100
	Etest								1	1
C. pelliculosa (2)	CLSI-MIC			1	-	1	-		-		-
	MFC				-	1	-	1	-		-						100
	Etest	1		1
K. ohmeri (8)	CLSI-MIC				-	8	-		-		-
	MFC				-		-	2	-	6	-						100
	Etest	2	2	3	1
C. neoformans (7)	CLSI-MIC				-	1	-	6	-		-
	MFC				-		-		-	5	-	2					100
	Etest		2	4	1
Y. lipolytica (4)	CLSI-MIC				-	1	-	1	-	2	-
	MFC				-		-	1	-		-	1	2				75
	Etest					1			1	1		1
T. asahii (4)	CLSI-MIC				-		-		-	1	-	1	2
	MFC				-		-		-		-	1	1	2			100
	Etest								1				1			2
Total (92)	CLSI-MIC			9	-	43	-	29	-	8	-	1	2
	MFC				-	3	-	28	-	37	-	17	5	2			97.8
	Etest	8	9	18	11	14	6	8	9	4		2	1			2

^∗ –, not tested;

^† , Percentage of MFCs that are within ±2 dilutions of CLSI-MICs.

Abbreviations: MIC, minimum inhibitory concentration; MFC, minimum fungicidal concentration; CLSI, Clinical and Laboratory Standards Institute.

Table 2.

Distribution of Etest MICs in relation with the CLSI MICs or MFCs for 92 yeast isolates

Test method	N of isolates displaying the dilution difference when Etest MICs are compared:							% agreement^∗
Test method	>-2	-2	-1	0	+1	+2	>+2	% agreement^∗
Etest with CLSI	7	8	9	57	9	0	2	90.2
Etest with MFCs	24	17	34	10	5	0	2	71.7

^∗ , Percentage of Etest MICs that are within ±2 dilutions of CLSI-MICs or MFCs.

Abbreviations: See Table 1.

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