Rapid and Accurate Molecular Identification of the Emerging Multidrug-Resistant Pathogen Candida auris.
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ABSTRACT:
SUBMITTER: Kordalewska M
PROVIDER: S-EPMC5527423 | biostudies-other | 2017 Aug
REPOSITORIES: biostudies-other
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Project description:Candida auris is a recently described pathogenic fungus that is causing invasive outbreaks on all continents. The fungus is of high concern given the numbers of multidrug-resistant strains that have been isolated in distinct sites across the globe. The fact that its diagnosis is still problematic suggests that the spreading of the pathogen remains underestimated. Notably, the molecular mechanisms of virulence and antifungal resistance employed by this new species are largely unknown. In the present work, we compared two clinical isolates of C. auris with distinct drug susceptibility profiles and a Candida albicans reference strain using a multi-omics approach. Our results show that, despite the distinct drug resistance profile, both C. auris isolates appear to be very similar, albeit with a few notable differences. However, compared to C. albicans both C. auris isolates have major differences regarding their carbon utilization and downstream lipid and protein content, suggesting a multifactorial mechanism of drug resistance. The molecular profile displayed by C. auris helps to explain the antifungal resistance and virulence phenotypes of this new emerging pathogen.IMPORTANCECandida auris was first described in Japan in 2009 and has now been the cause of significant outbreaks across the globe. The high number of isolates that are resistant to one or more antifungals, as well as the high mortality rates from patients with bloodstream infections, has attracted the attention of the medical mycology, infectious disease, and public health communities to this pathogenic fungus. In the current work, we performed a broad multi-omics approach on two clinical isolates isolated in New York, the most affected area in the United States and found that the omic profile of C. auris differs significantly from C. albicans In addition to our insights into C. auris carbon utilization and lipid and protein content, we believe that the availability of these data will enhance our ability to combat this rapidly emerging pathogenic yeast.
| S-EPMC6561322 | biostudies-literature
Project description:From 2009, Candida auris has emerged as a multidrug-resistant ascomycete yeast pathogen with the capacity for easy transmission between patients and hospitals, as well as persistence on environmental surfaces. Its association with high mortalities, breakthrough and persistent candidaemia, inconsistencies in susceptibility testing results, misidentification by available commercial identification systems and treatment failure, complicates its management and detection. Within the last nine years, C. auris has been increasingly reported from far-Eastern Asia, the Middle East, Africa, Europe, South and North America with substantial fatalities and misidentification. Herein, I provide a systematic and thorough review of this emerging pathogen. Meta-analysis showed that at least 742 C. auris isolates have been reported in 16 countries, with most of these being from India (≥243), USA (≥232) and UK (≥103) (p-value = .0355) within 2013-2017. Most isolates were from males (64.76%) (p-value = .0329) and blood (67.48%) (p-value < .0001), with substantial crude mortality (29.75%) (p-value = .0488). Affected patients presented with other comorbidities: diabetes (≥52), sepsis (≥48), lung diseases (≥39), kidney diseases (≥32) etc. (p-value < .0001). Resistance to fluconazole (44.29%), amphotericin B (15.46%), voriconazole (12.67%), caspofungin (3.48%) etc. were common (p-value = .0059). Commonly used diagnostic tools included PCR (30.38%), Bruker MALDI-TOF MS (14.00%), Vitek 2 YST ID (11.93%), AFLP (11.55%) and WGS (10.04%) (p-value = .002). Multidrug resistance, high attributable mortality and persistence are associated with C. auris infections. Two novel drugs, SCY-078 and VT-1598, are currently in the pipeline. Contact precautions, strict infection control, periodic surveillance and cleaning with chlorine-based detergents, efficient, faster and cheaper detection tools are necessary for prevention, containment and early diagnosis of C. auris infections.
| S-EPMC6079168 | biostudies-literature
Project description:BackgroundCandida auris is a multidrug resistant, emerging agent of fungemia in humans. Its actual global distribution remains obscure as the current commercial methods of clinical diagnosis misidentify it as C. haemulonii. Here we report the first draft genome of C. auris to explore the genomic basis of virulence and unique differences that could be employed for differential diagnosis.ResultsMore than 99.5 % of the C. auris genomic reads did not align to the current whole (or draft) genome sequences of Candida albicans, Candida lusitaniae, Candida glabrata and Saccharomyces cerevisiae; thereby indicating its divergence from the active Candida clade. The genome spans around 12.49 Mb with 8527 predicted genes. Functional annotation revealed that among the sequenced Candida species, it is closest to the hemiascomycete species Clavispora lusitaniae. Comparison with the well-studied species Candida albicans showed that it shares significant virulence attributes with other pathogenic Candida species such as oligopeptide transporters, mannosyl transfersases, secreted proteases and genes involved in biofilm formation. We also identified a plethora of transporters belonging to the ABC and major facilitator superfamily along with known MDR transcription factors which explained its high tolerance to antifungal drugs.ConclusionsOur study emphasizes an urgent need for accurate fungal screening methods such as PCR and electrophoretic karyotyping to ensure proper management of fungemia. Our work highlights the potential genetic mechanisms involved in virulence and pathogenicity of an important emerging human pathogen namely C. auris. Owing to its diversity at the genomic scale; we expect the genome sequence to be a useful resource to map species specific differences that will help develop accurate diagnostic markers and better drug targets.
| S-EPMC4562351 | biostudies-literature
Project description:The limited number of antifungals and the emergence of multidrug-resistant Candida auris pose a significant challenge to human medicine. Here, we utilized combinatorial drug therapy as an approach to augment the activity of current azole antifungals against C. auris. We evaluated the fluconazole chemosensitization activity of 1547 FDA-approved drugs and clinical molecules against an azole-resistant strain of C. auris. This led to the discovery that lopinavir, an antiviral drug, is a potent agent capable of sensitizing C. auris to the effect of azole antifungals. At a therapeutically achievable concentration (4-8 µg/ml), lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole, against C. auris (ΣFICI ranged from 0.05-0.50). The lopinavir/itraconazole combination enhanced the survival rate of C. auris-infected Caenorhabditis elegans by 90% and reduced the fungal burden in infected nematodes by 88.5% (p < 0.05). Moreover, lopinavir enhanced the antifungal activity of itraconazole against other medically important Candida species including C. albicans, C. tropicalis, C. glabrata, C. tropicalis, and C. parapsilosis. Comparative transcriptomic profiling revealed that lopinavir interferes with glucose permeation and ATP synthesis. This compromises the function of the efflux pumps presents in C. auris enhancing sensitivity to azole antifungals, as demonstrated by Nile red efflux assays. This study presents lopinavir as a novel, potent and broad-spectrum azole chemosensitizing agent that warrants further investigation against recalcitrant Candida infections.
2020-10-06 | GSE148341 | GEO
Project description:Outbreaks of multidrug-resistant Candida auris infections, associated with a mortality rate of 30% to 60%, are of serious global concern. Candida auris demonstrates high transmission rates in hospital settings; however, its rapid and accurate identification using currently available clinical identification techniques is challenging. In this study, we developed a rapid and effective method for detecting C. auris based on recombinase-aided amplification combined with lateral flow strips (RAA-LFS). We also screened the appropriate reaction conditions. Furthermore, we investigated the specificity and sensitivity of the detection system and its ability to distinguish other fungal strains. Candida auris was accurately identified and differentiated from related species at 37°C within 15 min. The minimum detection limit was 1 CFU (or 10 fg/reaction) and was not affected by high concentrations of related species or host DNA. The simple and cost-efficient detection method established in this study exhibited high specificity and sensitivity and successfully detected C. auris in simulated clinical samples. Compared with other traditional detection methods, this method greatly reduces the time and cost of testing and is thus suitable for hospitals or clinics in remote underfunded areas for screening C. auris infection and colonization. IMPORTANCE Candida auris is a highly lethal, multidrug-resistant, invasive fungus. However, conventional methods of C. auris identification are time-consuming and laborious and have low sensitivity and high error rates. In this study, a new molecular diagnostic method based on recombinase-aided amplification combined with lateral flow strips (RAA-LFS) was developed, and accurate results could be obtained by catalyzing the reaction at body temperature for 15 min. This method can be used for rapid clinical detection of C. auris, consequently saving valuable treatment time for patients.
| S-EPMC10269898 | biostudies-literature
Project description:OBJECTIVES:Corynebacterium striatum is an emerging multidrug-resistant (MDR) pathogen of immunocompromised and chronically ill patients. The objective of these studies was to provide a detailed genomic analysis of disease-causing C. striatum and determine the genomic drivers of resistance and resistance-gene transmission. METHODS:A multi-institutional and prospective pathogen genomics programme flagged seven MDR C. striatum infections occurring close in time, and specifically in immunocompromised patients with underlying respiratory diseases. Whole genome sequencing was used to identify clonal relationships among strains, genetic causes of antimicrobial resistance, and their mobilization capacity. Matrix-assisted linear desorption/ionization-time-of-flight analyses of sequenced isolates provided curated content to improve rapid clinical identification in subsequent cases. RESULTS:Epidemiological and genomic analyses identified a related cluster of three out of seven C. striatum among lung transplant patients who had common procedures and exposures at an outlying institution. Genomic analyses further elucidated drivers of the MDR phenotypes, including resistance genes mobilized by IS3504 and ISCg9a-like insertion sequences. Seven mobilizable resistance genes were localized to a common chromosomal region bounded by unpaired insertion sequences, suggesting that a single recombination event could spread resistance to aminoglycosides, macrolides, lincosamides and tetracyclines to naive strains. CONCLUSION:In-depth genomic studies of MDR C. striatum reveal its capacity for clonal spread within and across healthcare institutions and identify novel vectors that can mobilize multiple forms of drug resistance, further complicating efforts to treat infections in immunocompromised populations.
| S-EPMC6037610 | biostudies-literature
Project description:Combination therapies can be a promising tool to augment the antifungal activity of azole drugs against resistant Candida species. Here, we report the interaction between aprepitant, an antiemetic agent, and azole drugs against different Candida species including the emerging multidrug-resistant C. auris. Particularly, aprepitant enhanced the antifungal activity of itraconazole against C. auris by reducing its minimum inhibitory concentration (MIC) by 2-8 folds. Using Caenorhabditis elegans as an in vivo infection model, the aprepitant/itraconazole combination significantly prolonged the survival of the infected nematodes by ~90% and reduced the fungal burden by ~92% relative to the untreated control. Interestingly, the aprepitant/itraconazole combination exerted a potent fungicidal activity against both planktonic and adherent C. auris biofilms. Further, aprepitant/itraconazole displayed broad-spectrum synergistic interactions against other medically important Candida species including C. albicans, C. krusie, C. tropicalis, and C. parapsilosis (ƩFICI ranged from 0.08 to 031). Comparative transcriptomic profiling indicated aprepitant/itraconazole interferes significantly with metal ions homeostasis and compromises the ROS (reactive oxygen species) detoxification ability of C. auris. This study presents aprepitant as a novel, potent and broad-spectrum azole chemosensitizing agent that warrants further investigation.
2020-10-19 | GSE148749 | GEO
Project description:Stenotrophomonas maltophilia is emerging as an important cause of disease in nosocomial and community-acquired settings, including bloodstream, wound and catheter-associated infections. Cystic fibrosis (CF) airways also provide optimal growth conditions for various opportunistic pathogens with high antibiotic tolerance, including S. maltophilia. Currently, there is no rapid, cost-effective and accurate molecular method for detecting this potentially life-threatening pathogen, particularly in polymicrobial specimens, suggesting that its true prevalence is underestimated. Here, we used large-scale comparative genomics to identify a specific genetic target for S. maltophilia, with subsequent development and validation of a real-time PCR assay for its detection. Analysis of 167 Stenotrophomonas spp. genomes identified a conserved 4 kb region in S. maltophilia, which was targeted for Black Hole Quencher assay design. Our assay yielded the positive detection of 89 of 89 (100%) clinical S. maltophilia strains, and no amplification of 23 non-S. maltophilia clinical isolates. S. maltophilia was detected in 10 of 16 CF sputa, demonstrating the assay's utility for direct detection in respiratory specimens. The assay demonstrated good sensitivity, with limits of detection and quantitation on pure culture of ~10 and ~100 genome equivalents, respectively. Our assay provides a highly specific, sensitive and cost-effective method for the accurate identification of S. maltophilia, and will improve the diagnosis and treatment of this under-recognized pathogen by enabling its accurate and rapid detection from polymicrobial clinical and environmental samples.
| S-EPMC6861864 | biostudies-literature
Project description:The limited therapeutic options and the recent emergence of multidrug-resistant Candida species present a significant challenge to human medicine and underscore the need for novel therapeutic approaches. Drug repurposing appears as a promising tool to augment the activity of current azole antifungals, especially against multidrug-resistant Candida auris In this study, we evaluated the fluconazole chemosensitization activities of 1,547 FDA-approved drugs and clinical molecules against azole-resistant C. auris This led to the discovery that lopinavir, an HIV protease inhibitor, is a potent agent capable of sensitizing C. auris to the effect of azole antifungals. At a therapeutically achievable concentration, lopinavir exhibited potent synergistic interactions with azole drugs, particularly with itraconazole against C. auris (fractional inhibitory concentration index [ΣFICI] ranged from 0.04 to 0.09). Additionally, the lopinavir/itraconazole combination enhanced the survival rate of C. auris-infected Caenorhabditis elegans by 90% and reduced the fungal burden in infected nematodes by 88.5% (P < 0.05) relative to that of the untreated control. Furthermore, lopinavir enhanced the antifungal activity of itraconazole against other medically important Candida species, including C. albicans, C. tropicalis, C. krusei, and C. parapsilosis Comparative transcriptomic profiling and mechanistic studies revealed that lopinavir was able to significantly interfere with the glucose permeation and ATP synthesis. This compromised the efflux ability of C. auris and consequently enhanced the susceptibility to azole drugs, as demonstrated by Nile red efflux assays. Altogether, these findings present lopinavir as a novel, potent, and broad-spectrum azole-chemosensitizing agent that warrants further investigation against recalcitrant Candida infections.
| S-EPMC7927799 | biostudies-literature
Project description:The Gram-negative bacterium Cupriavidus gilardii is an emerging multidrug-resistant pathogen found in many environments. However, little is known about this species or its antibiotic resistance mechanisms. We used biochemical tests, antibiotic susceptibility experiments, and whole-genome sequencing to characterize an environmental C. gilardii isolate. Like clinical isolates, this isolate was resistant to meropenem, gentamicin, and other antibiotics. Resistance to these antibiotics appeared to be related to the large number of intrinsic antibiotic resistance genes found in this isolate. As determined by comparative genomics, this resistome was also well conserved in the only two other C. gilardii strains sequenced to date. The intrinsic resistome of C. gilardii did not include the colistin resistance gene mcr-5, which was in a transposon present only in one strain. The intrinsic resistome of C. gilardii was comprised of (i) many multidrug efflux pumps, such as a homolog of the Pseudomonas aeruginosa MexAB-OprM pump that may be involved in resistance to meropenem, other β-lactams, and aminoglycosides; (ii) a novel β-lactamase (OXA-837) that decreases susceptibility to ampicillin but not to other β-lactams tested; (iii) a new aminoglycoside 3-N-acetyltransferase [AAC(3)-IVb, AacC10] that decreases susceptibility to gentamicin and tobramycin; and (iv) a novel partially conserved aminoglycoside 3"-adenylyltransferase [ANT(3")-Ib, AadA32] that decreases susceptibility to spectinomycin and streptomycin. These findings provide the first mechanistic insight into the intrinsic resistance of C. gilardii to multiple antibiotics and its ability to become resistant to an increasing number of drugs during therapy.IMPORTANCE Cupriavidus gilardii is a bacterium that is gaining increasing attention both as an infectious agent and because of its potential use in the detoxification of toxic compounds and other biotechnological applications. In recent years, however, there has been an increasing number of reported infections, some of them fatal, caused by C. gilardii These infections are hard to treat because this bacterium is naturally resistant to many antibiotics, including last-resort antibiotics, such as carbapenems. Moreover, this bacterium often becomes resistant to additional antibiotics during therapy. However, little is known about C. gilardii and its antibiotic resistance mechanisms. The significance of our research is in providing, for the first time, whole-genome information about the natural antibiotic resistance genes found in this bacterium and their conservation among different C. gilardii strains. This information may provide new insights into the appropriate use of antibiotics in combating infections caused by this emerging pathogen.
| S-EPMC6796972 | biostudies-other