MicrobiType services: CgMT-C, CgFKS-hs1
$70/60/55/50 for 1/2/3/4 or more samples
The yeast Candida glabrata has emerged since the early 1990’s (the “fluconazole era”) as a major cause of mucosal and systemic disease, particularly in the immunocompromised, in ICU patients, or in individuals treated with broad spectrum antibiotics that eliminate the normal bacterial flora. There is evidence for nosocomial transmission (e.g., ref. 1), although relatively few studies have addressed this due to the lack of genotyping tools for C. glabrata that combine high resolution, reproducibility, and affordability. For example, an MLST system targeting 6 housekeeping genes has been developed for C. glabrata and employed in several studies (2), but its resolution is modest and its cost is high. Other genotyping systems that have been described rely on expensive equipment (e.g., microsatellite analysis by capillary electrophoresis) or have reproducibility/portability issues (e.g., pulsed-field gel electrophoresis).
Compared to other Candida species, C. glabrata has intrinsically low susceptibility to the most widely used antifungals, the azoles, and furthermore readily develops azole resistance. Fortunately, most C. glabrata isolates are highly susceptible to the echinocandins (caspofungin, micafungin, and anidulafungin). Consequently, echinocandins are now recommended as first line agents for serious infections with this opportunistic yeast. Acquired resistance to echinocandins is a rare event; nevertheless, the dramatically increased use of echinocandins in recent years has inevitably led to worrisome levels of resistance (e.g., 12% of C. glabrata isolates at one major medical center), including azole-echinocandin multidrug resistance (3). Echinocandin resistance most commonly results from various mutations in the so-called hot spot 1 regions of FKS1 or FKS2, which can be readily identified and tracked by DNA sequencing (4).
To address the need for affordable C. glabrata genotyping as an aid to epidemiological studies and infection control, MicrobiType offers CgMT-C. This PLST service targets polymorphic intergenic sequences on chromosome C, provides higher resolution than previously reported loci CgMT-J and CgMT-M (5), and has provided clear evidence for two instances of nosocomial transmission (6). Results are reported as a dendrogram showing the relationship of the submitted strain to a panel of diverse strains, and to other strains concurrently or previously submitted from your facility.
Additionally, MicrobiType offers CgFKS-hs1 for analysis of hot spot 1-based echinocandin resistance. Since resistance remains relatively rare, this service can further inform infection control efforts in the event that two or more C. glabrata isolates from a single facility exhibit echinocandin resistance. Results are reported in terms of the gene (FKS1 or FKS2) and the specific mutational change (nucleotide and amino acid).
(1) H. Miganti et al., 2011. Med. Mycol. 49:530
(2) T. J. Lott et al., 2010. Eukaryot. Cell 9:619
(3) B. D. Alexander et al., 2013. Clin. Infect. Dis. 56:1724
(4) S. K. Katiyar et al., 2012. Antimicrob. Agents Chemother. 56:6304. doi: 10.1128/AAC.00813-12.
(5) S. Katiyar et al., 2016. J. Clin. Microbiol. 54:1042. doi: 10.1128/JCM.03106-15.
(6) S. Katiyar and T. Edlind, 2021. J. Clin. Microbiol. doi: 10.1128/JCM.02933-20
(MicrobiType services are for research/investigational use only)