Method-dependent epidemiological cutoff values (ECVs) for detection of triazole resistance in Candida and Aspergillus species for the SYO colorimetric broth and Etest agar diffusion methods

Although the Sensitrite Yeast-One (SYO) and Etest methods are widely utilized, interpretive criteria are not available for triazole susceptibility testing of Candida or Aspergillus species. We collected fluconazole, itraconazole, posaconazole and voriconazole SYO and Etest MICs from 39 laboratories representing all continents for (method-agent-dependent): 11,171 Candida albicans, 215 C. dubliniensis, 4,418 C. glabrata species complex (SC), 157 C. (Meyerozyma) guilliermondii, 676 C. krusei (Pichia kudriavzevii), 298 C (Clavispora) lusitaniae, 911 and 3,691 C. parapsilosissensu stricto (SS) and C. parapsilosisSC, respectively, 36 C. metapsilosis, 110 C. orthopsilosis, 1,854 C. tropicalis, 244 Saccharomyces cerevisiae, 1,409 Aspergillus fumigatus, 389 A. flavus, 130 A. nidulans, 233 A. niger, and 302 A. terreus complexes. SYO/Etest MICs for 282 confirmed non-WT isolates were included: ERG11 (C. albicans), ERG11 and MRR1 (C. parapsilosis), cyp51A (A. fumigatus), and CDR2, CDR1 overexpression (C. albicans and C. glabrata, respectively). Interlaboratory modal agreement was superior by SYO for yeast spp., and by the Etest for Aspergillus spp. Distributions fulfilling CLSI criteria for ECV definition were pooled and we proposed SYO ECVs for S. cerevisiae, 9 yeast and 3 Aspergillus species, and Etest ECVs for 5 yeast and 4 Aspergillus species. The posaconazole SYO ECV of 0.06 \ub5g/ml for C. albicans and the Etest itraconazole ECV of 2 \ub5g/ml for A. fumigatus were the best predictors of non-WT isolates. These findings support the need for method-dependent ECVs, as overall, the SYO appears to perform better for susceptibility testing of yeast spp. and the Etest for Aspergillus spp. Further evaluations should be conducted with more Candida mutants

Disseminated fatal Talaromyces (Penicillium) marneffei infection in a returning HIV-infected traveller

We report a case of disseminated fatal Talaromyces (Penicillium) marneffei infection in an HIV-infected, antiretroviral treatment-experienced South African woman who had travelled to mainland China. The 37-year-old woman was admitted to a private hospital in fulminant septic shock and died within 12 h of admission. Intracellular yeast-like bodies were observed on the peripheral blood smear. A serum cryptococcal antigen test was negative. Blood cultures flagged positive after 2 days; on direct microscopy, yeast-like bodies were observed and a thermally dimorphic fungus, confirmed as T. marneffei, was cultured after 5 days. The clinical features of HIV-associated disseminated penicilliosis overlap with those of tuberculosis and endemic deep fungal infections. In the southern African context, where systemic opportunistic fungal infections such as cryptococcosis are more common among HIV-infected patients with a CD4+ count of <100 cells/µL, this infection is not likely to be considered in the differential diagnosis unless a travel history is obtained

Simultaneous Emergence of Multidrug-Resistant Candida auris on 3 Continents Confirmed by Whole-Genome Sequencing and Epidemiological Analyses

Background. Candida auris, a multidrug-resistant yeast that causes invasive infections, was first described in 2009 in Japan and has since been reported from several countries. Methods. To understand the global emergence and epidemiology of C. auris, we obtained isolates from 54 patients with C. auris infection from Pakistan, India, South Africa, and Venezuela during 2012-2015 and the type specimen from Japan. Patient information was available for 41 of the isolates. We conducted antifungal susceptibility testing and whole-genome sequencing (WGS). Results. Available clinical information revealed that 41% of patients had diabetes mellitus, 51% had undergone recent surgery, 73% had a central venous catheter, and 41% were receiving systemic antifungal therapy when C. auris was isolated. The median time from admission to infection was 19 days (interquartile range, 9-36 days), 61% of patients had bloodstream infection, and 59% died. Using stringent break points, 93% of isolates were resistant to fluconazole, 35% to amphotericin B, and 7% to echinocandins41% were resistant to 2 antifungal classes and 4% were resistant to 3 classes. WGS demonstrated that isolates were grouped into unique clades by geographic region. Clades were separated by thousands of single-nucleotide polymorphisms, but within each clade isolates were clonal. Different mutations in ERG11 were associated with azole resistance in each geographic clade. Conclusions. C. auris is an emerging healthcare-associated pathogen associated with high mortality. Treatment options are limited, due to antifungal resistance. WGS analysis suggests nearly simultaneous, and recent, independent emergence of different clonal populations on 3 continents. Risk factors and transmission mechanisms need to be elucidated to guide control measures.National Institute of Allergy and Infectious DiseasesUnited States Agency for International Development (USAID)Advanced Molecular Detection initiative at the CDCCtr Dis Control & Prevent, Mycot Dis Branch, Atlanta, GA USABroad Inst MIT & Harvard, Cambridge, MA USAJMI Labs, North Liberty, IA USAAga Khan Univ, Dept Pathol & Lab Med, Karachi, PakistanCtr Dis Control & Prevent, Field Epidemiol & Lab Training Program, Islamabad, PakistanUniv Delhi, Vallabhbhai Patel Chest Inst, Dept Med Mycol, Delhi, IndiaCtr Opportunist Trop & Hosp Infect, Natl Inst Communicable Dis, Johannesburg, South AfricaFed Univ Sao Paulo UNIFESP, Div Infect Dis, Sao Paulo, BrazilUniv Zulia, Sch Med, Dept Infect Dis, Maracaibo, VenezuelaCanisius Wilhelmina Hosp, Dept Med Microbiol & Infect Dis, Nijmegen, NetherlandsRadboudumc, Dept Med Microbiol, Nijmegen, NetherlandsFed Univ Sao Paulo UNIFESP, Div Infect Dis, Sao Paulo, BrazilNational Institute of Allergy and Infectious Diseases: U19AI110818USAID: 4-338/PAK-US/HEC/2010/932Web of Scienc

Etest ECVs/ECOFFs for detection of resistance in prevalent and three non-prevalent Candida spp. to triazoles and amphotericin B and Aspergillus spp. to caspofungin: Further assessment of modal variability

International audienceSusceptibility testing is an important tool in the clinical setting; its utility is based on the availability of categorical endpoints, breakpoints (BPs) or epidemiological cutoff values (ECVs/ECOFFs). CLSI and EUCAST have developed antifungal susceptibility testing, BPs and ECVs for some fungal species. Although the Concentration Gradient Strip BioMerieux Etest is useful for routine testing in the clinical laboratory, ECVs are not available for all agent/species; the lack of clinical data precludes development of BPs. We re-evaluated and consolidated Etest data points from three previous studies, and included new data. We defined ECOFFinder Etest ECVs for three sets of species/agent combinations: fluconazole, posaconazole and voriconazole and 8 Candida spp.; amphotericin B and 3 non-prevalent Candida spp.; and caspofungin and 5 Aspergillus spp. The total of Etest MICs from 23 laboratories (Europe, the Americas, South Africa) included (antifungal agent/dependent): 17,242 Candida albicans, 244 C. dubliniensis, 5,129 C. glabrata species complex (SC), 275 C. guilliermondii (Meyerozyma guilliermondii), 1,133 C. krusei (Pichia kudriavzevii), 933 C. kefyr (Kluyveromyces marxianus), 519 C. lusitaniae (Clavispora lusitaniae), 2,947 C. parapsilosis SC, 2,214 C. tropicalis, 3,212 Aspergillus fumigatus, 232 A. flavus, 181 A. niger, and 267 A. terreus SC isolates. Triazole MICs for 66 confirmed non-wild-type (non-WT) Candida isolates were available (ERG11 point mutations). Distributions fulfilling CLSI ECV criteria were pooled and ECOFFinder Etest ECVs were established for triazoles (9 Candida spp.); amphotericin B (3 less-prevalent Candida spp.) and caspofungin (4 Aspergillus spp.). Etest fluconazole ECVs could be good detectors of Candida non-WT isolates (59/61 Non-WT: 4 of 6 species)

Method-dependent epidemiological cutoff values for detection of triazole resistance in Candida and Aspergillus species for the Sensititre Yeastone colorimetric broth and etest agar diffusion methods

Although the Sensititre Yeast-One (SYO) and Etest methods are widely utilized, interpretive criteria are not available for triazole susceptibility testing of Candida or Aspergillus species. We collected fluconazole, itraconazole, posaconazole, and voriconazole SYO and Etest MICs from 39 laboratories representing all continents for (method/agent-dependent) 11,171 Candida albicans, 215 C. dubliniensis, 4,418 C. glabrata species complex, 157 C. guilliermondii (Meyerozyma guilliermondii), 676 C. krusei (Pichia kudriavzevii), 298 C. lusitaniae (Clavispora lusitaniae), 911 C. parapsilosis sensu stricto, 3,691 C. parapsilosis species complex, 36 C. metapsilosis, 110 C. orthopsilosis, 1,854 C. tropicalis, 244 Saccharomyces cerevisiae, 1,409 Aspergillus fumigatus, 389 A. flavus, 130 A. nidulans, 233 A. Niger, and 302 A. terreus complex isolates. SYO/Etest MICs for 282 confirmed non-wild-type (non-WT) isolates were included: ERG11 (C. albicans), ERG11 and MRR1 (C. parapsilosis), cyp51A (A. fumigatus), and CDR2 and CDR1 overexpression (C. albicans and C. glabrata, respectively). Interlaboratory modal agreement was superior by SYO for yeast species and by the Etest for Aspergillus spp. Distributions fulfilling CLSI criteria for epidemiological cutoff value (ECV) definition were pooled, and we proposed SYO ECVs for S. cerevisiae and 9 yeast and 3 Aspergillus species and Etest ECVs for 5 yeast and 4 Aspergillus species. The posaconazole SYO ECV of 0.06 g/ml for C. albicans and the Etest itraconazole ECV of 2 g/ml for A. fumigatus were the best predictors of non-WT isolates. These findings support the need for method-dependent ECVs, as, overall, the SYO appears to perform better for susceptibility testing of yeast species and the Etest appears to perform better for susceptibility testing of Aspergillus spp. Further evaluations should be conducted with more Candida mutants. Copyright © 2018 American Society for Microbiology. All Rights Reserved

Candida antifungal drug resistance in sub-Saharan African populations: A systematic review

BACKGROUND: Candida infections are responsible for increased morbidity and mortality rates in at-risk patients, especially in developing countries where there is limited access to antifungal drugs and a high burden of HIV co-infection. OBJECTIVES: This study aimed to identify antifungal drug resistance patterns within the subcontinent of Africa. METHODS: A literature search was conducted on published studies that employed antifungal susceptibility testing on clinical Candida isolates from sub-Saharan African countries using Pubmed and Google Scholar. RESULTS: A total of 21 studies from 8 countries constituted this review. Only studies conducted in sub-Saharan Africa and employing antifungal drug susceptibility testing were included. Regional differences in Candida species prevalence and resistance patterns were identified. DISCUSSION: The outcomes of this review highlight the need for a revision of antifungal therapy guidelines in regions most affected by Candida drug resistance. Better controls in antimicrobial drug distribution and the implementation of regional antimicrobial susceptibility surveillance programmes are required in order to reduce the high Candida drug resistance levels seen to be emerging in sub-Saharan Africa.This study was supported by the Research Office of the University of the Western Cape (project registration no. ScRIRC2012/10/72)