<i>MSH2</i>
            Gene Point Mutations Are Not Antifungal Resistance Markers in
            <i>Candida glabrata</i>

Bordallo-Cardona, María Ángeles; Agnelli, Caroline; Gómez-Núñez, Ana; Sánchez‐Carrillo, Carlos; Bouza, Emilio; Muñóz, Patricia; Escribano, Pilar; Guinea, Jesús

doi:10.1128/aac.01876-18

Cited by 24 publications

(24 citation statements)

References 29 publications

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“…We studied 10 pairs of molecularly identified C. glabrata isolates (26) involving parental echinocandin-susceptible isolates causing candidemia and isogenic echinocandin-resistant ones either generated in vitro (n ϭ 8) (27,28) or recovered from the heart valves of patients with concomitant endocarditis (n ϭ 2). Microsatellite markers showed that the parental and isogenic isolates had the same genotype (29). The characteristics of the isolates are shown in Table 3.…”

Section: Methodsmentioning

confidence: 99%

Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants

Bordallo-Cardona

Sánchez‐Carrillo

Bouza

et al. 2019

Antimicrob Agents Chemother

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Infections caused by the coexistence ofCandida glabrataechinocandin-resistant and echinocandin-susceptible cells may be possible, and the detection ofFKSmutants when the proportions ofFKSmutants are underrepresented poses a problem. We assessed the role of EUCAST and methods directly performed on positive blood cultures—Etest (ETDIR) and anidulafungin-containing agar plate assays—for detecting resistance inC. glabrataisolates containing different amounts of echinocandin-susceptible and -resistantCandida glabrataisolates. We studied 10 pairs ofC. glabrataisolates involving parental echinocandin-susceptible isolates and isogenic echinocandin-resistantFKSmutant isolates. Three inocula per pair (1 × 103to 5 × 103, 1 × 102to 5 × 102, and 10 to 50 CFU/ml) spanning suspensions with different amounts of susceptible/resistant isolates (9/1, 5/5, and 1/9 proportions for each the three inocula) were prepared. The suspensions were spiked in Bactec bottles and incubated until they were positive, and the three methods were compared. The EUCAST method showed echinocandin resistance when the bottles were spiked with susceptible/resistant isolates at 5/5 and 1/9 proportions; the results for the suspensions with a 9/1 proportion of susceptible/resistant isolates were susceptible for three pairs. We observed with the ETDIRresistance to both echinocandins in all pairs (resistance to micafungin and anidulafungin; MICs, ≥0.064 mg/liter and ≥0.125 mg/liter, respectively) and a double ring of growth inhibition in two pairs. The anidulafungin-containing plates showed fungal growth in the 90 spiked blood cultures at 48 h. Testing of echinocandin susceptibility with the ETDIRdirectly on the positive blood culture bottles is a reliable and rapid method to detect echinocandin resistance inC. glabrata. On the other hand, resistance can be missed with the EUCAST method when resistant isolates are underrepresented.

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Section: Methodsmentioning

confidence: 99%

Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants

Bordallo-Cardona

Sánchez‐Carrillo

Bouza

et al. 2019

Antimicrob Agents Chemother

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“…The acquisition of such mutations in genes associated with resistance may occur in the presence of specific mutations/absence of DNA repair mechanisms, such as mismatch repair (MSH2), resulting in increased antifungal tolerance and virulence [32,33]. Of note, the link between MSH2, in vitro tolerance, and clinical tolerance is uncertain [34,35].…”

Section: Antifungal Tolerance Molecular Mechanisms and Its Implicatiomentioning

confidence: 99%

“…Recently, it was proposed that the presence of mutation(s) in a gene of DNA repair pathway, MSH2, increases the propensity of clinical C. glabrata isolates to acquire in vitro resistance to antifungal drug(s) [60]. This notion has been evaluated in French [136], Chinese [124], Spanish [35], and Indian [137] clinical isolates of C. glabrata, and it appears that the presence of a mutation in MSH2 is associated with the genotype but not with the acquisition of antifungal resistance. Although, these clinical studies reported little or no resistance, which makes biological associations seems suspicious.…”

Section: Candida Glabratamentioning

confidence: 99%

“…glabrata isolates to acquire in vitro resistance to antifungal drug(s) [ 60 ]. This notion has been evaluated in French [ 136 ], Chinese [ 124 ], Spanish [ 35 ], and Indian [ 137 ] clinical isolates of C . glabrata , and it appears that the presence of a mutation in MSH2 is associated with the genotype but not with the acquisition of antifungal resistance.…”

Section: Epidemiology and Mechanisms Of Antifungal Resistance In Nmentioning

confidence: 99%

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The Quiet and Underappreciated Rise of Drug-Resistant Invasive Fungal Pathogens

Arastehfar

Lass‐Flörl

Garcia-Rubio

et al. 2020

JoF

114

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Human fungal pathogens are attributable to a significant economic burden and mortality worldwide. Antifungal treatments, although limited in number, play a pivotal role in decreasing mortality and morbidities posed by invasive fungal infections (IFIs). However, the recent emergence of multidrug-resistant Candida auris and Candida glabrata and acquiring invasive infections due to azole-resistant C. parapsilosis, C. tropicalis, and Aspergillus spp. in azole-naïve patients pose a serious health threat considering the limited number of systemic antifungals available to treat IFIs. Although advancing for major fungal pathogens, the understanding of fungal attributes contributing to antifungal resistance is just emerging for several clinically important MDR fungal pathogens. Further complicating the matter are the distinct differences in antifungal resistance mechanisms among various fungal species in which one or more mechanisms may contribute to the resistance phenotype. In this review, we attempt to summarize the burden of antifungal resistance for selected non-albicansCandida and clinically important Aspergillus species together with their phylogenetic placement on the tree of life. Moreover, we highlight the different molecular mechanisms between antifungal tolerance and resistance, and comprehensively discuss the molecular mechanisms of antifungal resistance in a species level.

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“…Indeed, in Cryptococcus , naturally occurring mutations in MSH2 have been shown to contribute to microevolution and population diversity (59, 60). Yet, recent clinical studies have not found an association between specific MSH2 alleles and drug resistance (27–29, 61, 62), raising the question of whether clinical isolates carrying these alleles are true mutators. To answer this question, it is necessary to measure and directly compare mutation rates between clinical isolates of C.…”

Section: Introductionmentioning

confidence: 99%

A Novel, Drug Resistance-Independent, Fluorescence-Based Approach To Measure Mutation Rates in Microbial Pathogens

Shor

Schuyler

Perlin

2019

mBio

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All evolutionary processes are underpinned by a cellular capacity to mutate DNA. To identify factors affecting mutagenesis, it is necessary to compare mutation rates between different strains and conditions. Drug resistance-based mutation reporters are used extensively to measure mutation rates, but they are suitable only when the compared strains have identical drug tolerance levels—a condition that is not satisfied under many “real-world” circumstances, e.g., when comparing mutation rates among a series of environmental or clinical isolates. Candida glabrata is a fungal pathogen that shows a high degree of genetic diversity and fast emergence of antifungal drug resistance. To enable meaningful comparisons of mutation rates among C. glabrata clinical isolates, we developed a novel fluorescence-activated cell sorting-based approach to measure the mutation rate of a chromosomally integrated GFP gene. We found that in Saccharomyces cerevisiae this approach recapitulated the reported mutation rate of a wild-type strain and the mutator phenotype of a shu1Δ mutant. In C. glabrata, the GFP reporter captured the mutation rate increases caused either by a genotoxic agent or by deletion of DNA mismatch repair gene MSH2, as well as the specific mutational signature associated with msh2Δ. Finally, the reporter was used to measure the mutation rates of C. glabrata clinical isolates carrying different alleles of MSH2. Together, these results show that fluorescence-based mutation reporters can be used to measure mutation rates in microbes under conditions of unequal drug susceptibility to reveal new insights about drivers of mutagenesis. IMPORTANCE Measurements of mutation rates—i.e., how often proliferating cells acquire mutations in their DNA—are essential for understanding cellular processes that maintain genome stability. Many traditional mutation rate measurement assays are based on detecting mutations that cause resistance to a particular drug. Such assays typically work well for laboratory strains but have significant limitations when comparing clinical or environmental isolates that have various intrinsic levels of drug tolerance, which confounds the interpretation of results. Here we report the development and validation of a novel method of measuring mutation rates, which detects mutations that cause loss of fluorescence rather than acquisition of drug resistance. Using this method, we measured the mutation rates of clinical isolates of fungal pathogen Candida glabrata. This assay can be adapted to other organisms and used to compare mutation rates in contexts where unequal drug sensitivity is anticipated.

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MSH2 Gene Point Mutations Are Not Antifungal Resistance Markers in Candida glabrata

Cited by 24 publications

References 29 publications

Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants

Detection of Echinocandin-Resistant Candida glabrata in Blood Cultures Spiked with Different Percentages of FKS2 Mutants

The Quiet and Underappreciated Rise of Drug-Resistant Invasive Fungal Pathogens

A Novel, Drug Resistance-Independent, Fluorescence-Based Approach To Measure Mutation Rates in Microbial Pathogens

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