Last data update: Apr 22, 2024. (Total: 46599 publications since 2009)
Records 1-16 (of 16 Records) |
Query Trace: Chow Nancy [original query] |
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Clade distribution of Candida auris in South Africa using whole genome sequencing of clinical and environmental isolates.
Naicker SD , Maphanga TG , Chow NA , Allam M , Kwenda S , Ismail A , Govender NPfor Germs- SA . Emerg Microbes Infect 2021 10 (1) 1300-1308 In South Africa, Candida auris was the third most common cause of candidemia in 2016-2017. We performed single nucleotide polymorphism (SNP) genome-wide analysis of 115 C. auris isolates collected between 2009 and 2018 from national laboratory-based surveillance, an environmental survey at four hospitals and a colonization study during a neonatal unit outbreak. The first known South African C. auris strain from 2009 clustered in clade IV. Overall, 98 strains clustered within clade III (85%), 14 within clade I (12%) and three within clade IV (3%). All environmental and colonizing strains clustered in clade III. We also identified known clade-specific resistance mutations in the ERG11 and FKS1 genes. Identification of clade I strains between 2016 and 2018 suggests introductions from South Asia followed by local transmission. SNP analysis characterized most C. auris strains into clade III, the clade first reported from South Africa, but the presence of clades I and IV strains also suggest early introductions from other regions. |
Candida auris Whole-Genome Sequence Benchmark Dataset for Phylogenomic Pipelines
Welsh RM , Misas E , Forsberg K , Lyman M , Chow NA . J Fungi (Basel) 2021 7 (3) Candida auris is a multidrug-resistant pathogen that represents a serious public health threat due to its rapid global emergence, increasing incidence of healthcare-associated outbreaks, and high rates of antifungal resistance. Whole-genome sequencing and genomic surveillance have the potential to bolster C. auris surveillance networks moving forward. Laboratories conducting genomic surveillance need to be able to compare analyses from various national and international surveillance partners to ensure that results are mutually trusted and understood. Therefore, we established an empirical outbreak benchmark dataset consisting of 23 C. auris genomes to help validate comparisons of genomic analyses and facilitate communication among surveillance networks. Our outbreak benchmark dataset represents a polyclonal phylogeny with three subclades. The genomes in this dataset are from well-vetted studies that are supported by multiple lines of evidence, which demonstrate that the whole-genome sequencing data, phylogenetic tree, and epidemiological data are all in agreement. This C. auris benchmark set allows for standardized comparisons of phylogenomic pipelines, ultimately promoting effective C. auris collaborations. |
Mitochondrial Genome Sequences of the Emerging Fungal Pathogen Candida auris .
Misas E , Chow NA , Gómez OM , Muñoz JF , McEwen JG , Litvintseva AP , Clay OK . Front Microbiol 2020 11 560332 Candida auris is an emerging fungal pathogen capable of causing invasive infections in humans. Since its first appearance around 1996, it has been isolated in countries spanning five continents. C. auris is a yeast that has the potential to cause outbreaks in hospitals, can survive in adverse conditions, including dry surfaces and high temperatures, and has been frequently misidentified by traditional methods. Furthermore, strains have been identified that are resistant to two and even all three of the main classes of antifungals currently in use. Several nuclear genome assemblies of C. auris have been published representing different clades and continents, yet until recently, the mitochondrial genomes (mtDNA chromosomes) of this species and the closely related species of C. haemulonii, C. duobushaemulonii, and C. pseudohaemulonii had not been analyzed in depth. We used reads from PacBio and Illumina sequencing to obtain a de novo reference assembly of the mitochondrial genome of the C. auris clade I isolate B8441 from Pakistan. This assembly has a total size of 28.2 kb and contains 13 core protein-coding genes, 25 tRNAs and the 12S and 16S ribosomal subunits. We then performed a comparative analysis by aligning Illumina reads of 129 other isolates from South Asia, Japan, South Africa, and South America with the B8441 reference. The clades of the phylogenetic tree we obtained from the aligned mtDNA sequences were consistent with those derived from the nuclear genome. The mitochondrial genome revealed a generally low genetic variation within clades, although the South Asian clade displayed two sub-branches including strains from both Pakistan and India. In particular, the 86 isolates from Colombia and Venezuela had mtDNA sequences that were all identical at the base level, i.e., a single conserved haplotype or mitochondrial background that exhibited characteristic differences from the Pakistan reference isolate B8441, such as a unique 25-nt insert that may affect function. |
Preliminary Estimates of the Prevalence of Selected Underlying Health Conditions Among Patients with Coronavirus Disease 2019 - United States, February 12-March 28, 2020.
CDC COVID-19 Response Team , Chow Nancy , Fleming-Dutra Katherine , Gierke Ryan , Hall Aron , Hughes Michelle , Pilishvili Tamara , Ritchey Matthew , Roguski Katherine , Skoff Tami , Ussery Emily . MMWR Morb Mortal Wkly Rep 2020 69 (13) 382-386 On March 11, 2020, the World Health Organization declared Coronavirus Disease 2019 (COVID-19) a pandemic (1). As of March 28, 2020, a total of 571,678 confirmed COVID-19 cases and 26,494 deaths have been reported worldwide (2). Reports from China and Italy suggest that risk factors for severe disease include older age and the presence of at least one of several underlying health conditions (3,4). U.S. older adults, including those aged ≥65 years and particularly those aged ≥85 years, also appear to be at higher risk for severe COVID-19-associated outcomes; however, data describing underlying health conditions among U.S. COVID-19 patients have not yet been reported (5). As of March 28, 2020, U.S. states and territories have reported 122,653 U.S. COVID-19 cases to CDC, including 7,162 (5.8%) for whom data on underlying health conditions and other known risk factors for severe outcomes from respiratory infections were reported. Among these 7,162 cases, 2,692 (37.6%) patients had one or more underlying health condition or risk factor, and 4,470 (62.4%) had none of these conditions reported. The percentage of COVID-19 patients with at least one underlying health condition or risk factor was higher among those requiring intensive care unit (ICU) admission (358 of 457, 78%) and those requiring hospitalization without ICU admission (732 of 1,037, 71%) than that among those who were not hospitalized (1,388 of 5,143, 27%). The most commonly reported conditions were diabetes mellitus, chronic lung disease, and cardiovascular disease. These preliminary findings suggest that in the United States, persons with underlying health conditions or other recognized risk factors for severe outcomes from respiratory infections appear to be at a higher risk for severe disease from COVID-19 than are persons without these conditions. |
Severe Outcomes Among Patients with Coronavirus Disease 2019 (COVID-19) - United States, February 12-March 16, 2020.
CDC COVID-19 Response Team , Bialek Stephanie , Boundy Ellen , Bowen Virginia , Chow Nancy , Cohn Amanda , Dowling Nicole , Ellington Sascha , Gierke Ryan , Hall Aron , MacNeil Jessica , Patel Priti , Peacock Georgina , Pilishvili Tamara , Razzaghi Hilda , Reed Nia , Ritchey Matthew , Sauber-Schatz Erin . MMWR Morb Mortal Wkly Rep 2020 69 (12) 343-346 Globally, approximately 170,000 confirmed cases of coronavirus disease 2019 (COVID-19) caused by the 2019 novel coronavirus (SARS-CoV-2) have been reported, including an estimated 7,000 deaths in approximately 150 countries (1). On March 11, 2020, the World Health Organization declared the COVID-19 outbreak a pandemic (2). Data from China have indicated that older adults, particularly those with serious underlying health conditions, are at higher risk for severe COVID-19-associated illness and death than are younger persons (3). Although the majority of reported COVID-19 cases in China were mild (81%), approximately 80% of deaths occurred among adults aged ≥60 years; only one (0.1%) death occurred in a person aged ≤19 years (3). In this report, COVID-19 cases in the United States that occurred during February 12-March 16, 2020 and severity of disease (hospitalization, admission to intensive care unit [ICU], and death) were analyzed by age group. As of March 16, a total of 4,226 COVID-19 cases in the United States had been reported to CDC, with multiple cases reported among older adults living in long-term care facilities (4). Overall, 31% of cases, 45% of hospitalizations, 53% of ICU admissions, and 80% of deaths associated with COVID-19 were among adults aged ≥65 years with the highest percentage of severe outcomes among persons aged ≥85 years. In contrast, no ICU admissions or deaths were reported among persons aged ≤19 years. Similar to reports from other countries, this finding suggests that the risk for serious disease and death from COVID-19 is higher in older age groups. |
Geographic Differences in COVID-19 Cases, Deaths, and Incidence - United States, February 12-April 7, 2020.
CDC COVID-19 Response Team , Bialek Stephanie , Bowen Virginia , Chow Nancy , Curns Aaron , Gierke Ryan , Hall Aron , Hughes Michelle , Pilishvili Tamara , Ritchey Matthew , Roguski Katherine , Silk Benjamin , Skoff Tami , Sundararaman Preethi , Ussery Emily , Vasser Michael , Whitham Hilary , Wen John . MMWR Morb Mortal Wkly Rep 2020 69 (15) 465-471 Community transmission of coronavirus disease 2019 (COVID-19) was first detected in the United States in February 2020. By mid-March, all 50 states, the District of Columbia (DC), New York City (NYC), and four U.S. territories had reported cases of COVID-19. This report describes the geographic distribution of laboratory-confirmed COVID-19 cases and related deaths reported by each U.S. state, each territory and freely associated state,* DC, and NYC during February 12-April 7, 2020, and estimates cumulative incidence for each jurisdiction. In addition, it projects the jurisdiction-level trajectory of this pandemic by estimating case doubling times on April 7 and changes in cumulative incidence during the most recent 7-day period (March 31-April 7). As of April 7, 2020, a total of 395,926 cases of COVID-19, including 12,757 related deaths, were reported in the United States. Cumulative COVID-19 incidence varied substantially by jurisdiction, ranging from 20.6 cases per 100,000 in Minnesota to 915.3 in NYC. On April 7, national case doubling time was approximately 6.5 days, although this ranged from 5.5 to 8.0 days in the 10 jurisdictions reporting the most cases. Absolute change in cumulative incidence during March 31-April 7 also varied widely, ranging from an increase of 8.3 cases per 100,000 in Minnesota to 418.0 in NYC. Geographic differences in numbers of COVID-19 cases and deaths, cumulative incidence, and changes in incidence likely reflect a combination of jurisdiction-specific epidemiologic and population-level factors, including 1) the timing of COVID-19 introductions; 2) population density; 3) age distribution and prevalence of underlying medical conditions among COVID-19 patients (1-3); 4) the timing and extent of community mitigation measures; 5) diagnostic testing capacity; and 6) public health reporting practices. Monitoring jurisdiction-level numbers of COVID-19 cases, deaths, and changes in incidence is critical for understanding community risk and making decisions about community mitigation, including social distancing, and strategic health care resource allocation. |
Tracing the Evolutionary History and Global Expansion of Candida auris Using Population Genomic Analyses.
Chow NA , Munoz JF , Gade L , Berkow EL , Li X , Welsh RM , Forsberg K , Lockhart SR , Adam R , Alanio A , Alastruey-Izquierdo A , Althawadi S , Arauz AB , Ben-Ami R , Bharat A , Calvo B , Desnos-Ollivier M , Escandon P , Gardam D , Gunturu R , Heath CH , Kurzai O , Martin R , Litvintseva AP , Cuomo CA . mBio 2020 11 (2) Candida auris has emerged globally as a multidrug-resistant yeast that can spread via nosocomial transmission. An initial phylogenetic study of isolates from Japan, India, Pakistan, South Africa, and Venezuela revealed four populations (clades I, II, III, and IV) corresponding to these geographic regions. Since this description, C. auris has been reported in more than 30 additional countries. To trace this global emergence, we compared the genomes of 304 C. auris isolates from 19 countries on six continents. We found that four predominant clades persist across wide geographic locations. We observed phylogeographic mixing in most clades; clade IV, with isolates mainly from South America, demonstrated the strongest phylogeographic substructure. C. auris isolates from two clades with opposite mating types were detected contemporaneously in a single health care facility in Kenya. We estimated a Bayesian molecular clock phylogeny and dated the origin of each clade within the last 360 years; outbreak-causing clusters from clades I, III, and IV originated 36 to 38 years ago. We observed high rates of antifungal resistance in clade I, including four isolates resistant to all three major classes of antifungals. Mutations that contribute to resistance varied between the clades, with Y132F in ERG11 as the most widespread mutation associated with azole resistance and S639P in FKS1 for echinocandin resistance. Copy number variants in ERG11 predominantly appeared in clade III and were associated with fluconazole resistance. These results provide a global context for the phylogeography, population structure, and mechanisms associated with antifungal resistance in C. auris IMPORTANCE In less than a decade, C. auris has emerged in health care settings worldwide; this species is capable of colonizing skin and causing outbreaks of invasive candidiasis. In contrast to other Candida species, C. auris is unique in its ability to spread via nosocomial transmission and its high rates of drug resistance. As part of the public health response, whole-genome sequencing has played a major role in characterizing transmission dynamics and detecting new C. auris introductions. Through a global collaboration, we assessed genome evolution of isolates of C. auris from 19 countries. Here, we described estimated timing of the expansion of each C. auris clade and of fluconazole resistance, characterized discrete phylogeographic population structure of each clade, and compared genome data to sensitivity measurements to describe how antifungal resistance mechanisms vary across the population. These efforts are critical for a sustained, robust public health response that effectively utilizes molecular epidemiology. |
Use of whole-genome sequencing to detect an outbreak of Malassezia pachydermatis infection and colonization in a neonatal intensive care unit-California, 2015-2016.
Chow NA , Chinn R , Pong A , Schultz K , Kim J , Gade L , Jackson BR , Beer KD , Litvintseva AP . Infect Control Hosp Epidemiol 2020 41 (7) 1-3 Whole-genome sequencing confirmed the presence of a Malassezia pachydermatis outbreak among neonates in a neonatal intensive care unit. This technology supports the importance of adhering to infection prevention measures. |
Potential Fifth Clade of Candida auris, Iran, 2018.
Chow NA , de Groot T , Badali H , Abastabar M , Chiller TM , Meis JF . Emerg Infect Dis 2019 25 (9) 1780-1781 Four major clades of Candida auris have been described, and all infections have clustered in these 4 clades. We identified an isolate representative of a potential fifth clade, separated from the other clades by >200,000 single-nucleotide polymorphisms, in a patient in Iran who had never traveled outside the country. |
On the Origins of a Species: What Might Explain the Rise of Candida auris ?
Jackson BR , Chow N , Forsberg K , Litvintseva AP , Lockhart SR , Welsh R , Vallabhaneni S , Chiller T . J Fungi (Basel) 2019 5 (3) Candida auris is an emerging multidrug-resistant yeast first described in 2009 that has since caused healthcare-associated outbreaks of severe human infections around the world. In some hospitals, it has become a leading cause of invasive candidiasis. C. auris is markedly different from most other pathogenic Candida species in its genetics, antifungal resistance, and ability to spread between patients. The reasons why this fungus began spreading widely in the last decade remain a mystery. We examine available data on C. auris and related species, including genomic epidemiology, phenotypic characteristics, and sites of detection, to put forth hypotheses on its possible origins. C. auris has not been detected in the natural environment; related species have been detected in in plants, insects, and aquatic environments, as well as from human body sites. It can tolerate hypersaline environments and higher temperatures than most Candida species. We explore hypotheses about the pre-emergence niche of C. auris, whether in the environmental or human microbiome, and speculate on factors that might have led to its spread, including the possible roles of healthcare, antifungal use, and environmental changes, including human activities that might have expanded its presence in the environment or caused increased human contact. |
Genomic insights into multidrug-resistance, mating and virulence in Candida auris and related emerging species.
Munoz JF , Gade L , Chow NA , Loparev VN , Juieng P , Berkow EL , Farrer RA , Litvintseva AP , Cuomo CA . Nat Commun 2018 9 (1) 5346 Candida auris is an emergent multidrug-resistant fungal pathogen causing increasing reports of outbreaks. While distantly related to C. albicans and C. glabrata, C. auris is closely related to rarely observed and often multidrug-resistant species from the C. haemulonii clade. Here, we analyze near complete genome assemblies for the four C. auris clades and three related species, and map intra- and inter-species rearrangements across the seven chromosomes. Using RNA-Seq-guided gene predictions, we find that most mating and meiosis genes are conserved and that clades contain either the MTLa or MTLalpha mating loci. Comparing the genomes of these emerging species to those of other Candida species identifies genes linked to drug resistance and virulence, including expanded families of transporters and lipases, as well as mutations and copy number variants in ERG11. Gene expression analysis identifies transporters and metabolic regulators specific to C. auris and those conserved with related species which may contribute to differences in drug response in this emerging fungal clade. |
Multiple introductions and subsequent transmission of multidrug-resistant Candida auris in the USA: a molecular epidemiological survey.
Chow NA , Gade L , Tsay SV , Forsberg K , Greenko JA , Southwick KL , Barrett PM , Kerins JL , Lockhart SR , Chiller TM , Litvintseva AP . Lancet Infect Dis 2018 18 (12) 1377-1384 BACKGROUND: Transmission of multidrug-resistant Candida auris infection has been reported in the USA. To better understand its emergence and transmission dynamics and to guide clinical and public health responses, we did a molecular epidemiological investigation of C auris cases in the USA. METHODS: In this molecular epidemiological survey, we used whole-genome sequencing to assess the genetic similarity between isolates collected from patients in ten US states (California, Connecticut, Florida, Illinois, Indiana, Maryland, Massachusetts, New Jersey, New York, and Oklahoma) and those identified in several other countries (Colombia, India, Japan, Pakistan, South Africa, South Korea, and Venezuela). We worked with state health departments, who provided us with isolates for sequencing. These isolates of C auris were collected during the normal course of clinical care (clinical cases) or as part of contact investigations or point prevalence surveys (screening cases). We integrated data from standardised case report forms and contact investigations, including travel history and epidemiological links (ie, patients that had shared a room or ward with a patient with C auris). Genetic diversity of C auris within a patient, a facility, and a state were evaluated by pairwise differences in single-nucleotide polymorphisms (SNPs). FINDINGS: From May 11, 2013, to Aug 31, 2017, isolates that corresponded to 133 cases (73 clinical cases and 60 screening cases) were collected. Of 73 clinical cases, 66 (90%) cases involved isolates related to south Asian isolates, five (7%) cases were related to South American isolates, one (1%) case to African isolates, and one (1%) case to east Asian isolates. Most (60 [82%]) clinical cases were identified in New York and New Jersey; these isolates, although related to south Asian isolates, were genetically distinct. Genomic data corroborated five (7%) clinical cases in which patients probably acquired C auris through health-care exposures abroad. Among clinical and screening cases, the genetic diversity of C auris isolates within a person was similar to that within a facility during an outbreak (median SNP difference three SNPs, range 0-12). INTERPRETATION: Isolates of C auris in the USA were genetically related to those from four global regions, suggesting that C auris was introduced into the USA several times. The five travel-related cases are examples of how introductions can occur. Genetic diversity among isolates from the same patients, health-care facilities, and states indicates that there is local and ongoing transmission. FUNDING: US Centers for Disease Control and Prevention. |
Molecular epidemiology of Candida auris in Colombia reveals a highly-related, country-wide colonization with regional patterns in Amphotericin B resistance.
Escandon P , Chow NA , Caceres DH , Gade L , Berkow EL , Armstrong P , Rivera S , Misas E , Duarte C , Moulton-Meissner H , Welsh RM , Parra C , Pescador LA , Villalobos N , Salcedo S , Berrio I , Varon C , Espinosa-Bode A , Lockhart SR , Jackson BR , Litvintseva AP , Beltran M , Chiller TM . Clin Infect Dis 2018 68 (1) 15-21 Background: Candida auris is a multidrug-resistant yeast associated with hospital outbreaks worldwide. During 2015-2016, multiple outbreaks were reported in Colombia. We aimed to understand the extent of contamination in healthcare settings and to characterize the molecular epidemiology of C. auris in Colombia. Methods: We sampled patients, patient contacts, healthcare workers, and the environment in four hospitals with recent C. auris outbreaks. Using standardized protocols, people were swabbed at different body sites. Patient and procedure rooms were sectioned into four zones and surfaces were swabbed. We performed whole-genome sequencing (WGS) and antifungal susceptibility testing (AFST) on all isolates. Results: Seven (41%) of the 17 people swabbed were found to be colonized. C. auris was isolated from 37/322 (12%) environmental samples. These were collected from a variety of items in all four zones. WGS and AFST revealed that although isolates were similar throughout the country, isolates from the northern region were genetically distinct and more resistant to amphotericin B (AmB) than the isolates from central Colombia. Four novel non-synonymous mutations were found to be significantly associated with AmB resistance. Conclusions: Our results show that extensive C. auris contamination can occur and highlight the importance of adherence to appropriate infection control practices and disinfection strategies. Observed genetic diversity supports healthcare transmission and a recent expansion of C. auris within Colombia with divergent AmB susceptibility. |
Genome Sequence of a Multidrug-Resistant Candida haemulonii Isolate from a Patient with Chronic Leg Ulcers in Israel.
Chow NA , Gade L , Batra D , Rowe LA , Juieng P , Ben-Ami R , Loparev VN , Litvintseva AP . Genome Announc 2018 6 (15) Candida haemulonii is an emerging multidrug-resistant yeast that can cause invasive candidiasis. Here, we report the first genome sequence of C. haemulonii (isolate B11899) generated using PacBio sequencing technology. The estimated genome size was 13.3 Mb, with a GC content of 45.19%. |
Genome Sequence of the Amphotericin B-Resistant Candida duobushaemulonii Strain B09383.
Chow NA , Gade L , Batra D , Rowe LA , Juieng P , Loparev VN , Litvintseva AP . Genome Announc 2018 6 (13) Candida duobushaemulonii is a drug-resistant yeast that can cause invasive candidiasis. Here, we report the first genome sequence of C. duobushaemulonii, isolate B09383, generated using PacBio sequencing technology. The estimated genome size was 12.5 Mb with a GC content of 46.84%. |
Molecular detection of airborne Coccidioides in Tucson, Arizona.
Chow NA , Griffin DW , Barker BM , Loparev VN , Litvintseva AP . Med Mycol 2016 54 (6) 584-92 Environmental surveillance of the soil-dwelling fungus Coccidioides is essential for the prevention of Valley fever, a disease primarily caused by inhalation of the arthroconidia. Methods for collecting and detecting Coccidioides in soil samples are currently in use by several laboratories; however, a method utilizing current air sampling technologies has not been formally demonstrated for the capture of airborne arthroconidia. In this study, we collected air/dust samples at two sites (Site A and Site B) in the endemic region of Tucson, Arizona, and tested a variety of air samplers and membrane matrices. We then employed a single-tube nested qPCR assay for molecular detection. At both sites, numerous soil samples (n = 10 at Site A and n = 24 at Site B) were collected and Coccidioides was detected in two samples (20%) at Site A and in eight samples (33%) at Site B. Of the 25 air/dust samples collected at both sites using five different air sampling methods, we detected Coccidioides in three samples from site B. All three samples were collected using a high-volume sampler with glass-fiber filters. In this report, we describe these methods and propose the use of these air sampling and molecular detection strategies for environmental surveillance of Coccidioides. |
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