S A Messer

JMI Laboratories, North Liberty, Iowa, United States

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Publications (170)628.91 Total impact

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    ABSTRACT: The in vitro activity of isavuconazole and nine antifungal comparator agents was assessed using reference broth microdilution methods against 1,421 common and uncommon species of Candida from a 2012 global survey. Isolates were identified using CHROMagar, biochemical methods and sequencing of ITS and/or 28S regions. Candida spp. were classified as either susceptible or resistant and as wild type (WT) or non-WT using CLSI clinical breakpoints or epidemiological cutoff values, respectively, for the antifungal agents. Isolates included 1,421 organisms from 21 different species of Candida. Among Candida spp., resistance to all 10 tested antifungal agents was low (0.0-7.9 %). The vast majority of each species of Candida, with the exception of Candida glabrata, Candida krusei, and Candida guilliermondii (modal MICs of 0.5 µg/ml), were inhibited by ≤0.12 µg/ml of isavuconazole (99.0 %; range 94.3 % [Candida tropicalis] to 100.0 % [Candida lusitaniae and Candida dubliniensis]). C. glabrata, C. krusei, and C. guilliermondii were largely inhibited by ≤1 µg/ml of isavuconazole (89.7, 96.9 and 92.8 %, respectively). Decreased susceptibility to isavuconazole was most prominent with C. glabrata where the modal MIC for isavuconazole was 0.5 µg/ml for those strains that were SDD to fluconazole or WT to voriconazole, and was 4 µg/ml for those that were either resistant or non-WT to fluconazole or voriconazole, respectively. In conclusion, these data document the activity of isavuconazole and generally the low resistance levels to the available antifungal agents in a large, contemporary (2012), global collection of molecularly characterized species of Candida.
    Mycopathologia. 06/2014;
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    ABSTRACT: The antifungal broth microdilution (BMD) method of the European Committee on Antimicrobial Susceptibility Testing (EUCAST) was compared with Clinical and Laboratory Standards Institute (CLSI) BMD method M27-A3 for amphotericin B, flucytosine, anidulafungin, caspofungin, micafungin, fluconazole, isavuconazole, itraconazole, posaconazole, and voriconazole susceptibility testing of 357 isolates of Candida. The isolates were selected from global surveillance collections to represent both wildtype (WT) and non-WT MIC results for the azoles (12% of fluconazole and voriconazole results were non-WT) and the echinocandins (6% of anidulafungin and micafungin results were non-WT). The study collection included 114 isolates of C. albicans, 73 of C. glabrata, 76 of C. parapsilosis, 60 of C. tropicalis, and 34 of C. krusei. The overall essential agreement (EA) between EUCAST and CLSI results ranged from 78.9% (posaconazole) to 99.6% (flucytosine). The categorical agreement (CA) between methods and species of Candida was assessed using previously determined CLSI epidemiological cutoff values (ECVs). The overall CA between methods was 95.0% with 2.5% very major (VM) and major (M) discrepancies. The CA was >93% for all antifungal agents with the exception of caspofungin (84.6%), where 10% of the results were categorized as non-WT by the EUCAST method and WT by the CLSI method. Problem areas with low EA or CA include testing of amphotericin B, anidulafungin, and isavuconazole against C. glabrata, itraconazole and posaconazole against most species, and caspofungin against C. parapsilosis, C. tropicalis, and C. krusei. We confirm high level EA and CA (>90%) between the two methods for testing fluconazole, voriconazole, and micafungin against all five species. The results indicate that the EUCAST and CLSI methods produce comparable results for testing the systemically active antifungal agents against the five most common species of Candida; however, there are several areas where additional steps toward harmonization are warranted.
    Diagnostic microbiology and infectious disease 01/2014; · 2.45 Impact Factor
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    ABSTRACT: In this study, 1717 fungal clinical isolates causing invasive fungal infections were evaluated against nine antifungal agents using Clinical and Laboratory Standards Institute (CLSI) reference broth microdilution methods. The isolates comprised 1487 Candida spp., 109 Aspergillus spp., 86 non-Candida yeasts (including 52 isolates of Cryptococcus neoformans) and 35 rare moulds obtained during 2012 from 72 hospitals worldwide. Echinocandin resistance among Candida spp. was low, and resistance rates to anidulafungin, caspofungin and micafungin varied from 0.0% to 2.8% among different species. Echinocandin-resistant Candida glabrata were shown to have fks mutations (fks2 HS1 F659Y, F659del, S663F and S663P), and fluconazole resistance was also observed in those strains. One Candida krusei and one Candida dubliniensis had L701 M or S645P fks1 mutations, respectively. Candida tropicalis and C. glabrata had higher fluconazole resistance rates of 6.1% and 6.9%, respectively, compared with other Candida spp. Fluconazole-resistant C. tropicalis were collected in five countries (USA, China, Germany, Belgium and Thailand). Voriconazole was active against all Candida spp., inhibiting 91.2–99.7% of isolates using species-specific breakpoints. All agents except for the echinocandins and posaconazole were active against Cr. neoformans. Triazoles were active against other yeasts [MIC90 (minimum inhibitory concentration encompassing 90% of isolates tested), 2 μg/mL]. The echinocandins and the mould-active triazoles were active against Aspergillus [MIC/MEC90 (minimum effective concentration encompassing 90% of isolates tested) range, 0.015–2 μg/mL], but the activity of these agents was limited against uncommon mould species (MIC/MEC90 range, 4 μg/mL to >16 μg/mL).
    International Journal of Antimicrobial Agents. 01/2014;
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    ABSTRACT: Due to unacceptably high inter-laboratory variation among caspofungin MIC values, we evaluated the use of micafungin as a surrogate marker to predict the susceptibility of Candida to caspofungin using reference methods and species-specific interpretive criteria. MIC results for 3,764 strains of Candida (eight species), including 73 strains with fks mutations were used. Caspofungin MIC values and species-specific interpretive criteria were compared with those of micafungin to determine the % categorical agreement (%CA) and very major (VME), major (ME) and minor error rates as well as the ability to detect fks mutant strains of C. albicans (11 mutants), C. tropicalis (4), C. krusei (3) and C. glabrata (55). Overall %CA was 98.8% (0.2% VME and ME, 0.8% minor errors) using micafungin as the surrogate marker. Among the 60 isolates of C. albicans (9 isolates), C. tropicalis (5), C. krusei (2), and C. glabrata (44) that were non-susceptible (either intermediate or resistant) to both caspofungin and micafungin, 54 (90.0%) contained a mutation in fks1 or fks2. An additional 10 mutants of C. glabrata, two of C. albicans and one each of C. tropicalis and C. krusei were classified as susceptible to both antifungal agents. Using the epidemiological cutoff value (ECVs) of 0.12 μg/ml for caspofungin and 0.03 μg/ml for micafungin to differentiate wildtype (WT) from non-WT strains of C. glabrata, 80% of the C. glabrata mutants were non-WT for both agents (96% concordance). Micafungin may serve as an acceptable surrogate marker to predict susceptibility and resistance of Candida to caspofungin.
    Journal of clinical microbiology 10/2013; · 4.16 Impact Factor
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    ABSTRACT: Among 119 echinocandin non-wildtype (WT) Candida glabrata from two global surveys, mutations in fks hotspots (HS) were detected in 28 strains (7 countries; 8 USA states): 24 (85.7%) were non-WT for micafungin, 22 (78.6%) for anidulafungin, and 25 (89.3%) for caspofungin. Most common FKS substitutions among non-WT strains were at positions F659 (n=7) and S663 (n=7). Three isolates displaying WT MIC results had substitutions of F625Y, L630I, and D632Y or non-HS mutations. Mutations that have been reported to decrease the echinocandin binding to the1,3 β-D-glucan synthase were categorized as resistant by applying the new CLSI breakpoint criteria for all three echinocandins.
    Antimicrobial Agents and Chemotherapy 10/2013; · 4.57 Impact Factor
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    ABSTRACT: BACKGROUND: Isavuconazole is a new broad-spectrum triazole with a favorable pharmacokinetic and safety profile.METHODS: We report the MIC distributions for isavuconazole and 111 isolates of Candida (C. albicans [42 isolates], C. glabrata (25), C. parapsilosis (22), C. tropicalis (14), and C. krusei (8)) as determined by both CLSI and EUCAST broth microdilution (BMD) methods; also the comparative activity of isavuconazole, itraconazole, fluconazole, posaconazole, voriconazole and the three echinocandins was assessed against a recent (2011) global collection of 1,358 isolates of Candida spp., 101 of Aspergillus spp., 54 of non-Candida yeasts, and 21 of non-Aspergillus moulds as determined by CLSI BMD methods.RESULTS: The overall essential agreement (EA; ± two log2 dilutions) between the CLSI and EUCAST methods was 99.1% (EA ± 1 log 2 dilution, 90.1% [range 80.0-100.0%]). The activity of isavuconazole against the larger collection of Candida spp. and Aspergillus spp. was comparable to that of posaconazole and voriconazole: MIC90 values for these 3 triazoles against Candida spp. was 0.5, 1 and 0.25 μg/ml, respectively and against Aspergillus spp. was 2, 1 and 1 μg/ml, respectively. Isavuconazole showed good activity against Cryptococcus neoformans (MIC90, 0.12 μg/ml) and other non-Candida yeasts (MIC90, 1 μg/ml), but was less potent against non-Aspergillus moulds (MIC90, >8 μg/ml). MIC values for isavuconazole and three mucormycetes isolates were 4, 1 and 2 μg/ml, respectively, whereas all three were inhibited by 1 μg/ml of posaconazole.CONCLUSIONS: Isavuconazole demonstrates broad-spectrum activity against this global collection of opportunistic fungi and both CLSI and EUCAST methods may be used to test this agent against Candida with highly comparable results.
    Journal of clinical microbiology 06/2013; · 4.16 Impact Factor
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    ABSTRACT: The SENTRY Antimicrobial Surveillance Program monitors global susceptibility and resistance rates of newer and established antifungal agents. We report the echinocandin and triazole antifungal susceptibility patterns for 3,418 contemporary clinical isolates of yeasts and moulds. The isolates were obtained from 98 laboratories in 34 countries during 2010-2011. Yeasts not presumptively identified by CHROMAgar, trehalose test or growth at 42°C and all moulds were sequence identified using ITS and 28S (yeasts) or ITS,TEF, and 28S (moulds) genes. Susceptibility testing was performed against 7 antifungals (anidulafungin, caspofungin, micafungin, fluconazole, itraconazole, posaconazole, voriconazole) using CLSI methods. Resistance rates to all agents were determined using the new CLSI clinical breakpoints and epidemiological cutoff values criteria, as appropriate. Sequencing of fks hot spots was performed for echinocandin non-wildtype (WT) strains. Isolates included 3,107 Candida (21 species), 146 Aspergillus (9 species), 84 C. neoformans, 40 other moulds (23 species), and 41 other yeasts (9 species). Among Candida, resistance to the echinocandins was low (0.0-1.7%). C. albicans and C. glabrata that were resistant to anidulafungin, caspofungin, or micafungin were shown to have fks mutations. Resistance to fluconazole was low among isolates of C. albicans (0.4%), C. tropicalis (1.3%) and C. parapsilosis (2.1%); 8.8% of C. glabrata were resistant to fluconazole. Among echinocandin-resistant C. glabrata isolates from 2011, 38% were fluconazole-resistant. Voriconazole was active against all Candida spp. except C. glabrata (10.5% non-WT) whereas posaconazole showed decreased activity against C. albicans (4.4%) and C. krusei (15.2% non-WT). All agents except for the echinocandins were active vs. C. neoformans and the triazoles were active vs. other yeasts (MIC90, 2 μg/ml). The echinocandins and triazoles were active versus Aspergillus (MIC/MEC90 range, 0.015-2 μg/ml), but the echinocandins were not active vs. other moulds (MEC90 range, 4->16 μg/ml). Overall, echinocandin and triazole resistance rates were low; however, fluconazole and echinocandin co-resistance among C. glabrata strains warrants continued close surveillance.
    Journal of clinical microbiology 05/2013; · 4.16 Impact Factor
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    ABSTRACT: Background. Fluconazole (FLC) resistance is common in C. glabrata and echinocandins are often used as first line therapy. Resistance to echinocandin therapy has been associated with FKS1 and FKS2 gene alterations. Methods. We reviewed records of all patients with C. glabrata bloodstream infection at Duke Hospital over the past decade (2001-10) and correlated treatment outcome with MIC results and the presence of FKS gene mutations. For each isolate, MICs to FLC and echinocandins (anidulafungin [ANF], caspofungin [CSF], and micafungin [MCF]) and FKS1 and FKS2 gene sequences were determined. Results. Two hundred ninety-three episodes (313 isolates) of C. glabrata bloodstream infection were analyzed. Resistance to echinocandins increased from 4.9% to 12.3% and to FLC from 18% to 30% between 2001 and 2010, respectfully. Among the 78 FLC resistant isolates, 14.1% were resistant to one or more echinocandins. Twenty-five (7.9%) isolates harbored a FKS mutation. The predictor of a FKS mutant strain was prior echinocandin therapy (stepwise multivariable analysis, OR 19.647, 95% CI 7.19-58.1). Eighty percent (8/10) of patients infected with FKS mutants demonstrating intermediate or resistant MICs to an echinocandin and treated with an echinocandin failed to respond or responded initially but recurred. Conclusions. Echinocandin resistance is increasing, including among FLC resistant isolates. The new CLSI clinical breakpoints differentiate wild-type from C. glabrata strains bearing clinically significant FKS1/FKS2 mutations. These observations underscore the importance of knowing the local epidemiology and resistance patterns for Candida within institutions and susceptibility testing of echinocandins for C. glabrata to guide therapeutic decision making.
    Clinical Infectious Diseases 03/2013; · 9.37 Impact Factor
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    ABSTRACT: MK-3118, a glucan synthase inhibitor derived from enfumafungin, and comparator agents were tested against 71 Aspergillus spp., including itraconazole-resistant strains (MIC, ≥4 μg/ml), using CLSI and EUCAST reference broth microdilution methods. CLSI MEC/MIC(90) values (μg/ml) for MK-3118, amphotericin B, and caspofungin, respectively, were: Aspergillus flavus species complex (SC), 0.12, 2, 0.03; A. fumigatus SC, 0.25, 2, 0.06; A. terreus SC, 0.12, 2, 0.06 and A. niger SC, 0.06, 1, 0.03. Essential agreement between CLSI and EUCAST (±2 log(2) dilution steps) was 94.3%. MK-3118 was determined to be a potent agent regardless of the in vitro method applied, with excellent activity against contemporary wild type and itraconazole-resistant strains of Aspergillus spp.
    Antimicrobial Agents and Chemotherapy 12/2012; · 4.57 Impact Factor
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    ABSTRACT: OBJECTIVES: To evaluate the activity of the orally bioavailable enfumafungin derivative MK-3118 and comparator antifungal agents tested against a collection of 113 clinical isolates of Candida spp. using CLSI and EUCAST broth microdilution (BMD) methods. METHODS: Candida spp. isolates (n = 113) were tested by CLSI and EUCAST methods. The collection contained 29 Candida albicans, 29 Candida glabrata, 21 Candida tropicalis, 15 Candida parapsilosis and 19 Candida krusei, including azole- and echinocandin-resistant isolates. CLSI and EUCAST MIC endpoints of 50% and 100% inhibition were determined using visual reading at 24 and 48 h of incubation and spectrophotometric reading at 24 h of incubation, respectively. RESULTS: MK-3118 CLSI MIC results ranged from 0.06 to 16 mg/L depending on species, duration of incubation and endpoint criteria (EC) used. Comparison of CLSI and EUCAST following 24 h of incubation and either 50% or 100% inhibition revealed an essential agreement (EA; ±2 doubling dilutions) of 99.1% using the 50% inhibition EC and 93.2% using the 100% inhibition EC. MK-3118 (24 h of incubation and 50% EC) was active against all the species tested and displayed similar potency to caspofungin (using CLSI BMD) against C. albicans (MIC(90), 1 and 2 mg/L, respectively), C. tropicalis (1 and 1 mg/L, respectively), C. parapsilosis (0.5 and 0.5 mg/L, respectively) and C. krusei (2 and 1 mg/L, respectively), but was 8-fold more potent than caspofungin against C. glabrata strains (MIC(90), 2 and 16 mg/L, respectively). MK-3118 was active against fluconazole-resistant strains as well as caspofungin-resistant strains with documented fks mutations. CONCLUSIONS: MK-3118 was documented to have potent in vitro activity against Candida spp. when tested by both CLSI and EUCAST BMD methods, with the highest overall EA (99.1%) obtained when MK-3118 MIC results were read after 24 h of incubation using a partial inhibition EC (50%).
    Journal of Antimicrobial Chemotherapy 11/2012; · 5.34 Impact Factor
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    ABSTRACT: A commercially prepared dried colorimetric microdilution panel (Sensititre Yeast One, TREK Diagnostic Systems, Cleveland, OH, USA) was compared in 3 different laboratories with the Clinical and Laboratory Standards Institute (CLSI) reference microdilution method by testing 2 quality control strains, 25 reproducibility strains, and 404 isolates of Candida spp. against anidulafungin, caspofungin, and micafungin. Reference CLSI BMD MIC end points and YeastOne colorimetric end points were read after 24 h of incubation. Excellent (100%) essential agreement (within 2 dilutions) between the reference and colorimetric MICs was observed. Categorical agreement (CA) between the 2 methods was assessed using the new species-specific clinical breakpoints (CBPs): susceptible (S), ≤0.25 μg/mL; intermediate (I), 0.5 μg/mL; and resistant (R), ≥1 μg/mL, for C. albicans, C. tropicalis, and C. krusei, and ≤2 μg/mL (S), 4 μg/mL (I), and ≥8 μg/mL (R) for C. parapsilosis and all 3 echinocandins. The new CBPs for anidulafungin and caspofungin and C. glabrata are ≤0.12 μg/mL (S), 0.25 μg/mL (I), and ≥0.5 μg/mL (R), whereas those for micafungin are ≤0.06 μg/mL (S), 0.12 μg/mL (I), and ≥0.25 μg/mL (R). Due to the lack of CBPs for any of the echinocandins and C. lusitaniae, the epidemiological cutoff values (ECVs) were used for this species to categorize the isolates as wild-type (WT; MIC ≤ECV) and non-WT (MIC >ECV), respectively, for anidulafungin (≤2 μg/mL/>2 μg/mL), caspofungin (≤1 μg/mL/>1 μg/mL), and micafungin (≤0.5 μg/mL/>0.5 μg/mL). CA ranged from 93.6% (caspofungin) to 99.6% (micafungin) with less than 1% very major or major errors. The YeastOne colorimetric method remains comparable to the CLSI BMD reference method for testing the susceptibility of Candida spp. to the echinocandins when using the new (lower) CBPs and ECVs. Further study using defined fks mutant strains of Candida is warranted.
    Diagnostic microbiology and infectious disease 06/2012; 73(4):365-8. · 2.45 Impact Factor
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    ABSTRACT: The increasing diversity of opportunistic fungi causing serious invasive fungal infections (IFI) has been documented. Accurate identification (ID) is important in guiding therapy, determining prognosis for IFIs and in epidemiological surveys. We assessed the utility of PCR-based methods for the ID of yeasts and moulds that either were uncommon, failed conventional ID, or represented unusual biochemical or phenotypic profiles of common species. Among 1,790 viable fungal clinical isolates received during the SENTRY Program in 2010, 322 strains from 40 study sites had ID confirmed by molecular methods. Isolates were previously identified in participant institutions. Yeasts that were not confirmed by morphology on CHROMagar, growth at 45 °C (Candida albicans/dubliniensis), or assimilation of trehalose (C. glabrata) as well as non-Candida yeasts and all moulds were amplified and sequenced using primers amplifying one or more of the following genes: ITS, 28S, β-tubulin (Aspergillus spp.), TEF (Fusarium spp.), IGS (Trichosporon spp.). The isolates selected for molecular ID included 149 isolates of Candida species, 77 of Aspergillus species, 73 non-Candida yeasts, and 23 other moulds (a total of 41 different species). Overall, the ID determined by the submitting site was confirmed for 189 isolates (58.7 %): Aspergillus spp. (64.1 % correct); Candida spp. (60.1 % correct); non-Candida yeasts (58.9 % correct); non-Aspergillus moulds (30.4 % correct). Species with high levels of concordance between conventional and molecular ID included A. fumigatus (95.0 %), C. lusitaniae (100 %), C. dubliniensis (92.3 %), C. kefyr (100 %), and C. neoformans (90.2 %). Only 50.0 % of isolates of C. albicans and 59.1 % of C. glabrata selected due to unusual phenotypic or biochemical features were found to be correctly identified by the submitting site. Molecular methods for the identification of fungal pathogens are an important adjunct to the conventional identification of many less common clinically relevant yeasts and moulds including species of Candida with unusual or erroneous phenotypic or biochemical profiles. Molecular confirmation of fungal identification is essential in epidemiological surveys such as SENTRY.
    Mycopathologia 05/2012; 174(4):259-71. · 1.65 Impact Factor
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    ABSTRACT: The echinocandin class of antifungal agents is considered to be the first-line treatment of bloodstream infections (BSI) due to Candida glabrata. Recent reports of BSI due to strains of C. glabrata resistant to both fluconazole and the echinocandins are of concern and prompted us to review the experience of two large surveillance programs, the SENTRY Antimicrobial Surveillance Program for the years 2006 through 2010 and the Centers for Disease Control and Prevention population-based surveillance conducted in 2008 to 2010. The in vitro susceptibilities of 1,669 BSI isolates of C. glabrata to fluconazole, voriconazole, anidulafungin, caspofungin, and micafungin were determined by CLSI broth microdilution methods. Fluconazole MICs of ≥64 μg/ml were considered resistant. Strains for which anidulafungin and caspofungin MICs were ≥0.5 μg/ml and for which micafungin MICs were ≥0.25 μg/ml were considered resistant. A total of 162 isolates (9.7%) were resistant to fluconazole, of which 98.8% were nonsusceptible to voriconazole (MIC > 0.5 μg/ml) and 9.3%, 9.3%, and 8.0% were resistant to anidulafungin, caspofungin, and micafungin, respectively. There were 18 fluconazole-resistant isolates that were resistant to one or more of the echinocandins (11.1% of all fluconazole-resistant isolates), all of which contained an acquired mutation in fks1 or fks2. By comparison, there were no echinocandin-resistant strains detected among 110 fluconazole-resistant isolates of C. glabrata tested in 2001 to 2004. These data document the broad emergence of coresistance over time to both azoles and echinocandins in clinical isolates of C. glabrata.
    Journal of clinical microbiology 01/2012; 50(4):1199-203. · 4.16 Impact Factor
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    ABSTRACT: When clinical susceptibility breakpoints (CBPs) are absent, establishing wild-type (WT) MIC distributions and epidemiologic cutoff values (ECVs) provides a sensitive means for detecting emerging resistance to antimicrobials. We determined species-specific ECVs for fluconazole (FLC), posaconazole (PSC), and voriconazole (VRC) using a large global collection of Cryptococcus neoformans (CNEO) isolates obtained from the ARTEMIS and SENTRY Antimicrobial Surveillance Programs. From 2006 to 2009, 285 invasive clinical isolates of CNEO were collected from 61 centers worldwide (178 isolates from ARTEMIS and 107 from SENTRY) and susceptibility testing was performed against FLC, PSC, and VRC using Clinical and Laboratory Standards Institute M27-A3 broth microdilution method (72 h of incubation). The ARTEMIS isolates were tested at the University of Iowa and the SENTRY Program isolates were tested at JMI Laboratories, and the results were combined for analysis. An additional collection of 986 isolates tested against FLC between 1996 and 2008 were used to assess temporal trends in the frequency of non-WT isolates. The modal MICs (mg/L) for FLC, PSC, and VRC were 4, 0.12, and 0.06, respectively. The ECVs expressed as milligrams per liter (% of isolates that had MIC ≤ECV) for FLC, PSC, and VRC were 8 (96.9), 0.25 (96.5), and 0.12 (95.1), respectively. Temporal trends in the emergence of non-WT strains (% of isolate MICs >ECV) for the time periods 1996-2000, 2001-2004, and 2005-2008 for FLC were 4.2, 3.8, and 0.5, respectively. In the absence of CBPs for FLC, PSC, and VRC, these WT MIC distributions and ECVs will be useful in surveillance for detection of emergence of azole reduced susceptibility among CNEO. Application of the FLC ECV to a large collection of CNEO tested over time (1996-2008) revealed a decrease in the frequency of non-WT strains. These findings are consistent with those of more limited surveys in developed countries, suggesting that CNEO susceptibility to FLC has improved since the introduction of antiretroviral therapy. Continued surveillance using these ECVs for the azoles and CNEO appears warranted.
    Diagnostic microbiology and infectious disease 09/2011; 71(3):252-9. · 2.45 Impact Factor
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    ABSTRACT: When clinical susceptibility breakpoints (CBPs) are absent, establishing wild-type (WT) MIC distributions and epidemiological cutoff values (ECVs) provides a sensitive means for detecting emerging resistance. We determined species-specific ECVs for anidulafungin (ANF), caspofungin (CSF), micafungin (MCF), fluconazole (FLC), posaconazole (PSC), and voriconazole (VRC) for six rarer Candida species (819 strains) using isolates obtained from the ARTEMIS Program and the SENTRY Antimicrobial Surveillance Program, all tested by a reference broth microdilution method. The calculated ECVs, expressed in μg/ml (and the percentages of isolates that had MICs less than or equal to the ECVs), for ANF, CSF, MCF, FLC, PSC, and VRC, respectively, were 0.12 (95.2), 0.12 (97.8), 0.12 (100.0), 0.5 (95.7), 0.12 (98.6), and 0.03 (100.0) for Candida dubliniensis; 4 (100.0), 2 (96.0), 2 (99.1), 8 (95.0), 0.5 (97.5), and 0.25 (98.0) for C. guilliermondii; 0.25 (98.9), 0.03 (98.0), 0.12 (97.5), 1 (99.1), 0.25 (99.1), and 0.015 (100.0) for C. kefyr; 2 (100.0), 1 (99.6), 0.5 (96.6), 2 (96.1), 0.25 (98.6), and 0.03 (96.6) for C. lusitaniae; and 2 (100.0), 0.5 (100.0), 1 (100.0), 2 (98.0), 0.25 (97.1), and 0.06 (98.0) for C. orthopsilosis, but for C. pelliculosa, ECVs could be determined only for CSF (0.12 [94.4]), FLC (4 [98.2]), PSC (2 [98.2]), and VRC (0.25 [98.2]). In the absence of species-specific CBP values, these WT MIC distributions and ECVs will be useful for monitoring the emergence of reduced susceptibility to the triazole and echinocandin antifungals.
    Journal of clinical microbiology 09/2011; 49(11):3800-4. · 4.16 Impact Factor
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    ABSTRACT: To compare European Committee on Antimicrobial Susceptibility Testing (EUCAST) and CLSI broth microdilution (BMD) methods for testing the novel antifungal E1210 against a recent collection of 102 clinical isolates of Candida spp. Candida isolates (102) were tested by CLSI and EUCAST methods; 21 Candida albicans, 20 Candida glabrata, 25 Candida parapsilosis, 24 Candida tropicalis and 12 Candida krusei, including echinocandin- and azole-resistant isolates. CLSI and EUCAST MIC endpoints of 50% and 100% inhibition were determined using visual reading at 24 and 48 h of incubation and spectrophotometric reading at 24 h of incubation, respectively. E1210 CLSI MIC results ranged from ≤0.008 to only 1 mg/L (excluding C. krusei) depending on species, duration of incubation and endpoint criteria (EC). E1210 was not active against C. krusei (MIC(50) >16 mg/L). Overall essential agreement (EA; ±2 doubling dilutions) between the 24 and 48 h CLSI readings was 100% and 97.6% using the 50% and 100% inhibition EC, respectively. Slightly more trailing growth at 48 h was observed with the 100% inhibition EC. Comparison of the 50% and 100% endpoints at 24 h of incubation showed an overall EA of 100%. Comparison of CLSI and EUCAST read at 24 h of incubation and either 50% or 100% inhibition revealed an EA of 97.8% using the 50% inhibition EC and 88.9% using the 100% inhibition EC. E1210 was found to have potent in vitro activity against Candida spp. when tested by both CLSI and EUCAST BMD methods, with the highest overall EA (97.8%) obtained when E1210 MIC results were read after 24 h of incubation using a partial inhibition EC.
    Journal of Antimicrobial Chemotherapy 08/2011; 66(11):2581-4. · 5.34 Impact Factor
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    ABSTRACT: E1210 is a first-in-class broad-spectrum antifungal that suppresses hyphal growth by inhibiting fungal glycophosphatidylinositol (GPI) biosynthesis. In the present study, we extend these findings by examining the activity of E1210 and comparator antifungal agents against Aspergillus spp. by using the methods of the Clinical and Laboratory Standards Institute (CLSI) and the European Committee for Antimicrobial Susceptibility Testing (EUCAST) to test wild-type (WT) as well as amphotericin B (AMB)-resistant (-R) and azole-R strains (as determined by CLSI methods). Seventy-eight clinical isolates of Aspergillus were tested including 20 isolates of Aspergillus flavus species complex (SC), 22 of A. fumigatus SC, 13 of A. niger SC, and 23 of A. terreus SC. The collection included 15 AMB-R (MIC, ≥ 2 μg/ml) isolates of A. terreus SC and 10 itraconazole-R (MIC, ≥ 4 μg/ml) isolates of A. fumigatus SC (7 isolates), A. niger SC (2 isolates), and A. terreus SC (1 isolate). Comparator antifungal agents included anidulafungin, caspofungin, amphotericin B, itraconazole, posaconzole, and voriconazole. Both CLSI and EUCAST methods were highly concordant for E1210 and all comparators. The essential agreement (EA; ± 2 log(2) dilution steps) was 100% for all comparisons with the exception of posaconazole versus A. terreus SC (EA = 91.3%). The minimum effective concentration (MEC)/MIC(90) values (μg/ml) for E1210, anidulafungin, caspofungin, itraconazole, posaconazole, and voriconazole, respectively, were as follows for each species: for A. flavus SC, 0.03, ≤ 0.008, 0.12, 1, 1, and 1; for A. fumigatus SC, 0.06, 0.015, 0.12, >8, 1, and 4; for A. niger SC, 0.015, 0.03, 0.12, 4, 1, and 2; and for A. terreus SC, 0.06, 0.015, 0.12, 1, 0.5, and 1. E1210 was very active against AMB-R strains of A. terreus SC (MEC range, 0.015 to 0.06 μg/ml) and itraconazole-R strains of A. fumigatus SC (MEC range, 0.03 to 0.12 μg/ml), A. niger SC (MEC, 0.008 μg/ml), and A. terreus SC (MEC, 0.015 μg/ml). In conclusion, E1210 was a very potent and broad-spectrum antifungal agent regardless of in vitro method applied, with excellent activity against AMB-R and itraconazole-R strains of Aspergillus spp.
    Antimicrobial Agents and Chemotherapy 08/2011; 55(11):5155-8. · 4.57 Impact Factor
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    ABSTRACT: Minimum inhibitory concentration (MIC) data from the SENTRY Antimicrobial Surveillance Program generated by reference methods were analysed to compare the antifungal resistance profiles and species distribution of Candida bloodstream infection (BSI) isolates obtained from patients in the Intensive Care Unit (ICU) and those from non-ICU locations. Results from 79 medical centres between 2008 and 2009 were tabulated. MIC values were obtained for anidulafungin, caspofungin, micafungin, fluconazole, posaconazole and voriconazole. Recently revised Clinical and Laboratory Standards Institute breakpoints for resistance were employed. A total of 1752 isolates of Candida spp. were obtained from ICU (779; 44.5%) and non-ICU (973; 55.5%) settings. The frequency of ICU-associated Candida BSI was higher in Latin America (56.5%) compared with Europe (44.4%) and North America (39.6%). The frequency of candidaemia in the ICU decreased both in Latin America and North America over the 2-year study period. Approximately 96% of isolates both in ICU and non-ICU settings were caused by only five species (Candida albicans, Candida glabrata, Candida parapsilosis, Candida tropicalis and Candida krusei). Resistance both to azoles and echinocandins was uncommon in ICU and non-ICU settings. Overall, fluconazole resistance was detected in 5.0% of ICU isolates and 4.4% of non-ICU isolates. Candida glabrata was the only species in which resistance to azoles and echinocandins was noted, and this multidrug-resistant phenotype was found in both settings. In conclusion, the findings from this global survey indicate that invasive candidiasis can no longer be considered to be just an ICU-related infection, and efforts to design preventive and diagnostic strategies must be expanded to include other at-risk populations and hospital environments. Concern regarding C. glabrata must now include resistance to echinocandins as well as azole antifungal agents.
    International journal of antimicrobial agents 07/2011; 38(1):65-9. · 3.03 Impact Factor
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    ABSTRACT: The in vitro activity of the novel antifungal agent E1210 and four comparators (caspofungin, fluconazole, posaconazole, and voriconazole) was determined against 90 clinical isolates of Candida using Clinical and Laboratory Standards Institute methods. The collection was composed of 21 Candida albicans, 20 C. glabrata, 25 C. parapsilosis, and 24 C. tropicals, and also included 21 fluconazole-resistant and 15 caspofungin-resistant strains. E1210 was highly active against all the species tested and was more potent than all comparators. The MIC(90) results (μg/mL) for E1210, caspofungin, fluconazole, posaconazole, and voriconazole, respectively, were as follows by species: C. albicans (0.06, 4, ≥64, 0.5, 0.5), C. glabrata (0.06, 2, 32, 1, 1), C. parapsilosis (0.06, 4, 16, 0.12, 0.25), and C. tropicalis (0.06, 4, ≥64, 0.5, 2). E1210 was also the most active agent against fluconazole-resistant strains of C. albicans (MIC range, 0.015-0.12 μg/mL), C. glabrata (0.06 μg/mL), C. parapsilosis (MIC range, 0.06-0.05 μg/mL), and C. tropicalis (MIC range, 0.008-0.06 μg/mL), and was the most potent agent tested against caspofungin-resistant strains of C. albicans (MIC range, 0.008-0.12 μg/mL), C. glabrata (MIC range, 0.03-0.06 μg/mL), and C. tropicalis (MIC range, 0.015-0.06 μg/mL).
    Diagnostic microbiology and infectious disease 06/2011; 71(2):167-70. · 2.45 Impact Factor
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    ABSTRACT: We performed 24- and 48-h MIC determinations of posaconazole and voriconazole against more than 16,000 clinical isolates of Candida species. By using the 24- and 48-h epidemiological cutoff values (ECVs), the categorical agreement between the 24-h and reference 48-h broth microdilution results ranged from 97.1% (C. parapsilosis and voriconazole) to 99.8% (C. krusei and voriconazole), with 0.0 to 2.9% very major discrepancies (VMD). The essential agreement (within 2 log(2) dilutions) between the 24- and 48-h results was 99.6% for both posaconazole and voriconazole. The MIC results obtained for both posaconazole and voriconazole after only 24 h of incubation may be used to determine the susceptibilities of Candida spp. to these important antifungal agents. The applications of ECVs to this large collection of Candida isolates suggests the potential to develop 24-h species-specific clinical breakpoints for both posaconazole and voriconazole.
    Journal of clinical microbiology 02/2011; 49(4):1274-9. · 4.16 Impact Factor

Publication Stats

9k Citations
628.91 Total Impact Points

Institutions

  • 2004–2014
    • JMI Laboratories
      North Liberty, Iowa, United States
  • 2013
    • Duke University
      Durham, North Carolina, United States
  • 2011
    • Tufts University
      Georgia, United States
    • Richmond VA Medical Center
      Richmond, Virginia, United States
  • 1998–2011
    • University of Iowa
      • • Department of Pathology
      • • Department of Internal Medicine
      • • Department of Epidemiology
      • • College of Dentistry
      Iowa City, IA, United States
    • University of California, San Francisco
      • Division of Infectious Diseases
      San Francisco, California, United States
    • Case Western Reserve University School of Medicine
      • Department of Dermatology
      Cleveland, OH, United States
    • Medical University of South Carolina
      • Department of Pediatrics
      Charleston, SC, United States
    • University of Texas Medical School
      • Department of Internal Medicine
      Houston, Texas, United States
  • 2009–2010
    • University of Massachusetts Boston
      Boston, Massachusetts, United States
    • Johns Hopkins Medicine
      Baltimore, Maryland, United States
  • 2007
    • University of Texas at Tyler
      Tyler, Texas, United States
  • 2005
    • University of Malaya
      • Department of Medical Microbiology
      Kuala Lumpur, Kuala Lumpur, Malaysia
  • 2003
    • Universidade Federal de São Paulo
      • Escola Paulista de Medicina (EPM)
      São Paulo, Estado de Sao Paulo, Brazil
  • 2002
    • University of Wisconsin, Madison
      • Department of Medical Microbiology and Immunology
      Mississippi, United States
  • 2000
    • Case Western Reserve University
      Cleveland, Ohio, United States
  • 1999
    • Virginia Commonwealth University
      Richmond, Virginia, United States
  • 1996
    • Harbor-UCLA Medical Center
      Torrance, California, United States
  • 1995
    • University of Texas Health Science Center at San Antonio
      • Department of Pathology
      San Antonio, TX, United States