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1.
Bioinformatics ; 38(7): 1816-1822, 2022 03 28.
Article in English | MEDLINE | ID: mdl-35104333

ABSTRACT

MOTIVATION: Long-read phasing has been used for reconstructing diploid genomes, improving variant calling and resolving microbial strains in metagenomics. However, the phasing blocks of existing methods are broken by large Structural Variations (SVs), and the efficiency is unsatisfactory for population-scale phasing. RESULTS: This article presents a novel algorithm, LongPhase, which can simultaneously phase single nucleotide polymorphisms (SNPs) and SVs of a human genome in 10-20 min, 10× faster than the state-of-the-art WhatsHap, HapCUT2 and Margin. In particular, co-phasing SNPs and SVs produces much larger haplotype blocks (N50 = 25 Mbp) than those of existing methods (N50 = 10-15 Mbp). We show that LongPhase combined with Nanopore ultra-long reads is a cost-effective and highly contiguous solution, which can produce between one and 26 blocks per chromosome arm without the need for additional trios, chromosome-conformation and strand-seq data. AVAILABILITYAND IMPLEMENTATION: LongPhase is freely available at https://github.com/twolinin/LongPhase/. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Subject(s)
Algorithms , High-Throughput Nucleotide Sequencing , Humans , Sequence Analysis, DNA , Genome, Human , Haplotypes , Chromosomes/genetics
2.
Can J Infect Dis Med Microbiol ; 2020: 9205197, 2020.
Article in English | MEDLINE | ID: mdl-32318128

ABSTRACT

Shewanella algae is an emerging marine zoonotic pathogen and accounts for considerable mortality and morbidity in compromised hosts. However, there is scarce literature related to the understanding of the genetic background of virulence determinants in S. algae. In this study, we aim to determine the occurrence of common virulence genes in S. algae using whole-genome sequence and comparative genomic analysis. Comparative genomics reveals putative-virulence genes related to bile resistance, chemotaxis, hemolysis, and motility. We detected the existence of hlyA, hlyD, and hlyIII involved in hemolysis. We also found chemotaxis gene cluster cheYZA operon and cheW gene. The results provide insights into the genetic basis underlying pathogenicity in S. algae.

3.
Biol Blood Marrow Transplant ; 25(3): 594-598, 2019 03.
Article in English | MEDLINE | ID: mdl-30448456

ABSTRACT

In recent years, vancomycin-resistant Enterococcus (VRE) colonization is being increasingly encountered in transplant recipients, and VRE has become one of the leading causes of bacteremia early after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Data are sparse on the effect of empiric VRE therapy for febrile, neutropenic allo-HSCT recipients colonized with VRE. All allo-HSCT recipients aged ≥18years who developed VRE bacteremia (VREB) between 2005 and 2014 were identified and categorized as to whether they received empiric or directed VRE therapy. There were 434 (33%) VRE-colonized and 872 (67%) non-VRE-colonized patients during the study period, and 172 of the 434 (40%) VRE-colonized patients received empiric therapy. There was no significant difference in incidence of VREB among colonized patients who did or did not receive empiric therapy (28 of 172 [16%] vs 55 of 262 [21%]; P = .22). There were 95 patients with VREB, of which the majority (83 of 95; 87%) was known to be VRE-colonized. Of the 95 VREB episodes, 29 (31%) were treated with empiric VRE therapy, whereas 66 (69%) were treated with directed therapy. No significant differences in clinical outcomes, including median duration of bacteremia (2 days vs 2 days; P = .39), recurrent VREB (3 of 29 [10%] vs 5 of 66 [8%]; P = .65), 30-day all-cause mortality (1 of 29 [3%] vs 4 of 66 [6%]; P = .62), or VRE-attributable mortality (1 of 29 [3%] vs 1 of 66 [2%]; P = .55), were observed between the empiric therapy and directed therapy groups. Kaplan-Meier curve analysis showed no significant difference in survival at 30days in allo-HSCT recipients with VREB who received empiric therapy and those who received directed therapy (97% vs 94%; P = .62). Based on our data, we recommend against empiric use of VRE-active agents for fever and neutropenia in VRE-colonized patients undergoing allo-HSCT.


Subject(s)
Bacteremia/drug therapy , Hematopoietic Stem Cell Transplantation/adverse effects , Vancomycin-Resistant Enterococci/drug effects , Anti-Bacterial Agents/therapeutic use , Bacteremia/mortality , Fever/drug therapy , Fever/etiology , Humans , Neutropenia/drug therapy , Neutropenia/etiology , Retrospective Studies , Survival Analysis , Transplantation, Homologous/adverse effects , Treatment Outcome , Vancomycin Resistance
4.
Biol Blood Marrow Transplant ; 25(4): 791-799, 2019 04.
Article in English | MEDLINE | ID: mdl-30476551

ABSTRACT

We quantified cytomegalovirus (CMV) antiviral use and hospital length of stay (LOS) associated with CMV infection in a contemporary cohort of conventional (CONV) and CD34-selected (T cell-depleted) hematopoietic cell transplantation (HCT) recipients managed by preemptive therapy (PET) in a single US center. Adults who received first allogeneic HCT at Memorial Sloan Kettering Cancer Center from June 2010 through December 2014 were analyzed. Days on PET, number of readmissions, and readmission LOS by day 180 post-HCT were summarized. Estimated unit value (EUV) was defined as the expected number of PET days for a cohort of 100 HCT with characteristics as the analyzed cohort. Standardized incidence ratio was calculated as the ratio of observed outcomes of patients with CMV viremia over the outcomes of patients without CMV viremia. Of 318 patients, 88 received CONV and 230 CD34-selected HCT. Rates of CMV viremia were 26.3% for CONV and 41.9% for CD34-selected (P = .003). Among patients with viremia 68.2% CONV and 97.9% CD34-selected received PET. EUV for PET was 852 days and 2821 days for CONV and CD34-selected, respectively. The standardized incidence ratios for number of readmission and readmission LOS were 1.7 (95% confidence interval [CI], 1.4 to 2.1) and 1.2 (95% CI, 1.1 to 1.3), respectively, for CONV HCT and 1.7 (95% CI, 1.3 to 2.1) and 1.6 (95% CI, 1.5 to 1.7), respectively, for CD34-selected HCT. Overall survival was similar between patients with and without CMV viremia by HCT type. CMV end-organ disease was associated with lower overall survival only in CD34-selected HCT (P = .0007). CMV infection managed by PET requires substantial antiviral use and is associated with longer readmission LOS more, particularly among CD34-selected HCT.


Subject(s)
Cytomegalovirus Infections/etiology , Hematopoietic Stem Cell Transplantation/adverse effects , Transplantation Conditioning/adverse effects , Transplantation, Homologous/adverse effects , Female , Humans , Male , Middle Aged , Treatment Outcome
5.
Can J Infect Dis Med Microbiol ; 2019: 3840563, 2019.
Article in English | MEDLINE | ID: mdl-31281553

ABSTRACT

Shewanella algae is an emerging pathogen widely distributed in aquatic environment. Bacteremia is a major manifestation of S. algae infections, and there are increasing reports of antibiotic-resistant strains. However, little is known about the genomic characteristics of human bacteremic S. algae. Here, we report the results of the whole-genome sequencing of colistin-resistant S. algae TYL, a blood isolate. Chromosome-encoded pmrC associated with colistin resistance and bla OXA-55 gene intrinsic to S. algae was identified. Continuous surveillance for the emergence of S. algae is needed.

6.
Plant J ; 90(5): 994-1006, 2017 Jun.
Article in English | MEDLINE | ID: mdl-28258650

ABSTRACT

The chloroplast NAD(P)H dehydrogenase-like (NDH) complex consists of about 30 subunits from both the nuclear and chloroplast genomes and is ubiquitous across most land plants. In some orchids, such as Phalaenopsis equestris, Dendrobium officinale and Dendrobium catenatum, most of the 11 chloroplast genome-encoded ndh genes (cp-ndh) have been lost. Here we investigated whether functional cp-ndh genes have been completely lost in these orchids or whether they have been transferred and retained in the nuclear genome. Further, we assessed whether both cp-ndh genes and nucleus-encoded NDH-related genes can be lost, resulting in the absence of the NDH complex. Comparative analyses of the genome of Apostasia odorata, an orchid species with a complete complement of cp-ndh genes which represents the sister lineage to all other orchids, and three published orchid genome sequences for P. equestris, D. officinale and D. catenatum, which are all missing cp-ndh genes, indicated that copies of cp-ndh genes are not present in any of these four nuclear genomes. This observation suggests that the NDH complex is not necessary for some plants. Comparative genomic/transcriptomic analyses of currently available plastid genome sequences and nuclear transcriptome data showed that 47 out of 660 photoautotrophic plants and all the heterotrophic plants are missing plastid-encoded cp-ndh genes and exhibit no evidence for maintenance of a functional NDH complex. Our data indicate that the NDH complex can be lost in photoautotrophic plant species. Further, the loss of the NDH complex may increase the probability of transition from a photoautotrophic to a heterotrophic life history.


Subject(s)
Genome, Chloroplast/genetics , Genome, Plant/genetics , Orchidaceae/genetics , Plant Proteins/genetics
7.
Clin Infect Dis ; 66(2): 244-253, 2018 01 06.
Article in English | MEDLINE | ID: mdl-29020313

ABSTRACT

Background: Rates of invasive pneumococcal disease (IPD) declined since routine childhood immunization with the 7-valent pneumococcal conjugate vaccine (PCV7) in 2000. We studied the impact of PCV7 on the incidence of IPD in cancer patients. Methods: This was a retrospective analysis of adult and pediatric patients treated at Memorial Sloan Kettering Cancer Center from 1992 to 2012. Recovery of Streptococcus pneumoniae from a sterile site defined IPD. IPD incidence was calculated as cases per 1,000 unique patient-visits per year (UPV). IPD incidence was calculated for the periods: "before PCV7" (1992-2000), "after PCV7" (2001-2010) and "after PCV13" (2011-2012). Results: Of 343 IPD cases, 165, 155, and 23 cases occurred "before PCV7," "after PCV7" and "after PCV13" respectively. The IPD incidence declined from 0.43 "before PCV7" to 0.17 "after PCV7" (95% confidence interval [CI]: 0.33-0.46, P < .001) and 0.11 "after PCV13" (95% CI: 0.42-0.96, P = .004). Adults with hematologic malignancies and children had the highest incidence. In patients 1-4 years old, the incidence declined from 11.2 "before PCV7" to 2.38 "after PCV7" (79% decrease, 95% CI: 0.1-0.4, P < .001). In patients with hematologic malignancies, the incidence declined from 2.55 "before PCV7" to 0.92 "after PCV7" (64% decrease, 95% CI: 0.27-0.47, P < .001). Conclusions: The incidence of IPD among cancer patients sharply declined after introduction of PCV7; especially in high risk groups. The decline in adults suggests an indirect effect from PCV7 childhood vaccination.


Subject(s)
Heptavalent Pneumococcal Conjugate Vaccine/administration & dosage , Neoplasms/complications , Pneumococcal Infections/epidemiology , Pneumococcal Infections/prevention & control , Streptococcus pneumoniae/isolation & purification , Adolescent , Adult , Aged , Aged, 80 and over , Child , Child, Preschool , Female , Humans , Incidence , Infant , Infant, Newborn , Longitudinal Studies , Male , Middle Aged , Retrospective Studies , Young Adult
8.
Transpl Infect Dis ; 20(3): e12881, 2018 Jun.
Article in English | MEDLINE | ID: mdl-29570237

ABSTRACT

BACKGROUND: Cytomegalovirus (CMV) viremia after CD34+ -selected hematopoietic stem cell transplant (HCT) often requires prolonged antiviral therapy. We report rates and outcomes of resistant CMV in a contemporary cohort of CD34+ -selected HCT recipients managed preemptively. METHODS: We retrospectively reviewed 220 consecutive, CMV-seropositive recipients (R+), who received CD34+ -selected HCT at Memorial Sloan Kettering Cancer Center between June 2010 and December 2014. Patients were monitored by quantitative CMV PCR and were treated preemptively. CMV resistance was tested by a genotypic assay. RESULTS: One hundred and sixty-one (73%) patients developed CMV viremia and 47 (29% of viremic and 21% of total patients) had CMV resistance testing by one-year from HCT. CMV resistance was confirmed in 19 (12% of viremic and 9% of total) patients and was identified >3 months from HCT in 90% of patients. Twelve patients had mutations in UL97 only; the remaining 7 patients had mutations in UL54 only or UL54 and UL97. By 1 year from HCT, 11 of 19 (58%) patients with mutations had CMV end-organ disease. CMV-related mortality in patients with resistance was 42%. CONCLUSIONS: Nine percent of CMV R+, CD34+ -selected HCT recipients had resistant CMV by 1 year from HCT. Of 19 patients with resistant CMV, 58% had CMV end-organ disease and 42% died of CMV. Effective strategies for CMV prevention and restoration of CMV immunity are needed for CD34+ -selected HCT.


Subject(s)
Antigens, CD34/immunology , Cytomegalovirus Infections/immunology , Cytomegalovirus/immunology , Hematopoietic Stem Cell Transplantation/adverse effects , Adult , Aged , Cohort Studies , Cytomegalovirus/genetics , Cytomegalovirus Infections/prevention & control , Cytomegalovirus Infections/virology , DNA-Directed DNA Polymerase/genetics , Female , Genotype , Hematopoietic Stem Cell Transplantation/methods , Humans , Male , Middle Aged , Mutation , Retrospective Studies , Transplant Recipients , Viral Proteins/genetics , Viremia/prevention & control , Young Adult
9.
Transpl Infect Dis ; 20(6): e12977, 2018 Dec.
Article in English | MEDLINE | ID: mdl-30120866

ABSTRACT

Allogeneic hematopoietic cell transplant (HCT) recipients are at risk for herpes simplex virus (HSV) and varicella-zoster virus (VZV) infections. Routine prophylaxis with acyclovir is recommended during periods of immunosuppression. Brincidofovir (BCV, CMX001), a lipid conjugate of cidofovir, has shown in vitro activity against HSV/VZV, but has not been formally studied for HSV/VZV prophylaxis. We report our clinical experience of BCV for HSV/VZV prophylaxis in HCT recipients. This was a retrospective review of 30 hematopoietic cell transplant (HCT) recipients between 8/2010 and 8/2015 who received BCV doses not exceeding 200 mg/week for adults/adolescents and 4 mg/kg/week for pediatric (<12 years) patients, for ≥14 days BCV without concomitant acyclovir under clinical trials or single patient use. HSV/VZV cases during BCV treatment were confirmed by viral culture or PCR and clinical symptoms. Of 30 patients who met the inclusion criteria, 27 (90%) patients were adults and 22 (73%) patients received T-cell depleted HCT. The most common indications for BCV were cytomegalovirus in 12 patients (40%) and adenovirus in 11 patients (37%). One patient was treated for acyclovir-resistant HSV and one for disseminated VZV. There were two breakthrough cases of HSV infection during 2170 patient-days. There were no cases of breakthrough VZV infection. The overall rate of breakthrough HSV infection was 1.0 per 1000 patient-days, without any breakthrough VZV infections. Our study provides the only available-albeit limited-evidence on the potential efficacy of BCV for HSV/VZV prophylaxis in HCT patients. Additional studies are needed to further assess the efficacy and safety of BCV in the setting.


Subject(s)
Antibiotic Prophylaxis/methods , Cytosine/analogs & derivatives , Hematopoietic Stem Cell Transplantation/adverse effects , Herpes Simplex/prevention & control , Organophosphonates/therapeutic use , Varicella Zoster Virus Infection/prevention & control , Adult , Aged , Child , Child, Preschool , Cytosine/pharmacology , Cytosine/therapeutic use , Female , Herpes Simplex/epidemiology , Herpes Simplex/virology , Herpesvirus 3, Human/drug effects , Herpesvirus 3, Human/isolation & purification , Humans , Infant , Male , Middle Aged , Organophosphonates/pharmacology , Retrospective Studies , Simplexvirus/drug effects , Simplexvirus/isolation & purification , Treatment Outcome , Varicella Zoster Virus Infection/epidemiology , Varicella Zoster Virus Infection/virology , Young Adult
10.
Transpl Infect Dis ; 20(4): e12897, 2018 Aug.
Article in English | MEDLINE | ID: mdl-29668073

ABSTRACT

Recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT) are at high risk for invasive mold infections (IMI). The goal of the study is to describe the incidence and outcome of IMI in patients after allo-HSCT in a large cohort of patients receiving anti-mold prophylaxis. We conducted a retrospective review of 988 consecutive adults who underwent allo-HSCT in our center from 2008 through 2014. Standard prophylaxis consisted of micafungin 150 mg IV daily from admission to day +7 ± 3 followed by voriconazole until day +75 to +100. Cases meeting criteria for proven or probable IMI according to EORTC-MSG criteria were included. Median age at HSCT was 54 years. The most common diagnoses were acute myeloid leukemia (n = 351, 36%) and lymphoid malignancies (n = 248, 25%). Matched related or unrelated donors (URD) were used in 686 (69%) patients, mismatched URD in 142 (14%) and cord blood units in 154 (16%). Twenty-one patients were diagnosed with IMI after allo-HSCT, 19 probable and 2 proven, and one patient was diagnosed postmortem. Microbiological diagnosis was established in 9 cases, 5 of them being Aspergillus. One-year cumulative incidence (CI) of IMI was 1.6% (95% CI 0.9-2.5) while 12-week overall survival after IMI was 39% (95% CI 24-65) Analyzed by disease, there was a trend for a higher 1-year CI of IMI in patients with ALL (5% [95% CI 1.6-11.4]) when compared with AML (1.4%), MDS (1.5%) and lymphoma (1.2%), P = .06. The 1-year CI of IMI after transplantation is low in patients receiving anti-mold prophylaxis with micafungin bridged to voriconazole, although these infections are associated with a higher risk of mortality.


Subject(s)
Antibiotic Prophylaxis/methods , Antifungal Agents/therapeutic use , Fungi/isolation & purification , Hematopoietic Stem Cell Transplantation/adverse effects , Invasive Fungal Infections/epidemiology , Adult , Aged , Echinocandins/therapeutic use , Female , Hematologic Neoplasms/mortality , Hematologic Neoplasms/surgery , Humans , Incidence , Invasive Fungal Infections/microbiology , Invasive Fungal Infections/prevention & control , Lipopeptides/therapeutic use , Male , Micafungin , Middle Aged , Retrospective Studies , Transplantation, Homologous/adverse effects , Treatment Outcome , Voriconazole/therapeutic use , Young Adult
11.
Mem Inst Oswaldo Cruz ; 113(10): e180192, 2018 Aug 27.
Article in English | MEDLINE | ID: mdl-30204830

ABSTRACT

Raoultella planticola is an emerging zoonotic pathogen that is associated with rare but life-threatening cases of bacteremia, biliary tract infections, and urinary tract infections. Moreover, increasing antimicrobial resistance in the organism poses a potential threat to public health. In spite of its importance as a human pathogen, the genome of R. planticola remains largely unexplored and little is known about its virulence factors. Although lipopolysaccharides has been detected in R. planticola and implicated in the virulence in earlier studies, the genetic background is unknown. Here, we report the complete genome and comparative analysis of the multidrug-resistant clinical isolate R. planticola GODA. The complete genome sequence of R. planticola GODA was sequenced using single-molecule real-time DNA sequencing. Comparative genomic analysis reveals distinct capsular polysaccharide synthesis gene clusters in R. planticola GODA. In addition, we found bla TEM-57 and multiple transporters related to multidrug resistance. The availability of genomic data in open databases of this emerging zoonotic pathogen, in tandem with our comparative study, provides better understanding of R. planticola and the basis for future work.


Subject(s)
Enterobacteriaceae/genetics , Genes, Bacterial/genetics , Genome, Bacterial/genetics , Polysaccharides, Bacterial/biosynthesis , Bacterial Capsules/genetics , Enterobacteriaceae/classification , Polysaccharides, Bacterial/genetics
12.
BMC Bioinformatics ; 18(1): 524, 2017 Nov 28.
Article in English | MEDLINE | ID: mdl-29179672

ABSTRACT

BACKGROUND: High-throughput sequencing offers higher throughput and lower cost for sequencing a genome. However, sequencing errors, including mismatches and indels, may be produced during sequencing. Because, errors may reduce the accuracy of subsequent de novo assembly, error correction is necessary prior to assembly. However, existing correction methods still face trade-offs among correction power, accuracy, and speed. RESULTS: We develop a novel overlap-based error correction algorithm using FM-index (called FMOE). FMOE first identifies overlapping reads by aligning a query read simultaneously against multiple reads compressed by FM-index. Subsequently, sequencing errors are corrected by k-mer voting from overlapping reads only. The experimental results indicate that FMOE has highest correction power with comparable accuracy and speed. Our algorithm performs better in long-read than short-read datasets when compared with others. The assembly results indicated different algorithms has its own strength and weakness, whereas FMOE is good for long or good-quality reads. CONCLUSIONS: FMOE is freely available at https://github.com/ythuang0522/FMOC .


Subject(s)
Algorithms , High-Throughput Nucleotide Sequencing/methods , Animals , Bacteria/genetics , Base Sequence , Caenorhabditis elegans/genetics , Genome , Sequence Alignment , Time Factors
13.
Biol Blood Marrow Transplant ; 23(10): 1759-1766, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28668490

ABSTRACT

Recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) are at risk of infection by double-stranded (ds) DNA viruses. We report rates of dsDNA viremia, end-organ disease (EOD), infection-related mortality, and overall survival (OS) in a contemporary cohort of adult TCD HCT recipients routinely monitored for cytomegalovirus (CMV), adenovirus (ADV), human herpesvirus 6 (HHV6), and Epstein-Barr virus (EBV). Healthcare utilization in the first 6 months post-HCT was compared between patients with dsDNA viremia versus no viremia. This was an observational study of adult patients with acute leukemia and myelodysplastic syndrome who received CD34+ selected, peripheral blood HCT at Memorial Sloan Kettering Cancer Center from March 2012 through December 2014. Patients were prospectively monitored by quantitative PCR assays for CMV, ADV, HHV6, and EBV in whole blood or plasma. The cumulative incidence of viremia(s) at day +180, EOD at 1 year, and OS at 1 year were estimated by the Kaplan-Meier method and compared by the log-rank test among patient with and without viremia/EOD. Standardized incidence ratios were used to compare overall length of hospital stay (LOS), number of readmissions after HCT, and length of readmissions through day +180. Of 156 patients, 96 (62%) were CMV recipient seropositive. Forty-two patients received grafts from matched related (27%), 86 from matched unrelated (55%), and 28 from mismatched (18%) donors. Overall, 132 patients (85%) had ≥1 viremia and 52 (33%) ≥2 viremias by day +180. The cumulative incidences for CMV, HHV6, ADV, and EBV viremia were 44%, 61%, 7%, and 16%, respectively, with median times of onset 28 days (interquartile range [IQR], 25 to 33), 33 days (IQR, 25 to 47), 60 days (IQR, 19 to 84), and 79 days (IQR, 54 to 106) post-HCT, respectively. Twenty-eight patients (18%) developed EOD by dsDNA viruses at 1 year post-HCT. Treatment for CMV accounted for 91% total antiviral treatment-days. Compared with patients with no viremia, patients with CMV viremia, HHV6 viremia, or ≥2 viremias experienced longer LOS (P <.001) and a higher number of readmissions (P <.001) by day +180. OS rate at 1 year was 79% and was similar between patients with or without dsDNA viremias. EOD was associated with lower 1-year OS rates (63.4%) versus without EOD (81.1%) (P = .02). Of 33 patients who died, 10 died due to infection, and 7 of these infection-related deaths were due to dsDNA viruses. Viremia by dsDNA viruses occurred in 85% of TCD HCT recipients by day +100 and 33% of patients experienced ≥2 viremias by day +180. CMV accounted for most antiviral use. CMV, HHV6, or ≥2 viremias were associated with more readmissions and longer LOS. One year OS rate was 78%. EOD by dsDNA viruses was associated with decreased 1-year OS. Infections by dsDNA viruses pose a substantial burden after TCD HCT.


Subject(s)
Antigens, CD34 , Coinfection/etiology , DNA Viruses/pathogenicity , Hematopoietic Stem Cell Transplantation/adverse effects , Lymphocyte Depletion/methods , Adult , Aged , Female , Humans , Length of Stay , Leukemia, Myeloid, Acute/complications , Leukemia, Myeloid, Acute/therapy , Male , Middle Aged , Myelodysplastic Syndromes/complications , Myelodysplastic Syndromes/therapy , Survival Analysis , Viremia/diagnosis , Viremia/etiology , Viremia/genetics , Young Adult
14.
Bioinformatics ; 32(9): 1301-7, 2016 05 01.
Article in English | MEDLINE | ID: mdl-26755626

ABSTRACT

MOTIVATION: String and de Bruijn graphs are two graph models used by most genome assemblers. At present, none of the existing assemblers clearly outperforms the others across all datasets. We found that although a string graph can make use of entire reads for resolving repeats, de Bruijn graphs can naturally assemble through regions that are error-prone due to sequencing bias. RESULTS: We developed a novel assembler called StriDe that has advantages of both string and de Bruijn graphs. First, the reads are decomposed adaptively only in error-prone regions. Second, each paired-end read is extended into a long read directly using an FM-index. The decomposed and extended reads are used to build an assembly graph. In addition, several essential components of an assembler were designed or improved. The resulting assembler was fully parallelized, tested and compared with state-of-the-art assemblers using benchmark datasets. The results indicate that contiguity of StriDe is comparable with top assemblers on both short-read and long-read datasets, and the assembly accuracy is high in comparison with the others. AVAILABILITY AND IMPLEMENTATION: https://github.com/ythuang0522/StriDe CONTACT: : ythuang@cs.ccu.edu.tw SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Subject(s)
Algorithms , Genome , Animals , Humans , Sequence Analysis, DNA
15.
Clin Infect Dis ; 63(4): 565-8, 2016 08 15.
Article in English | MEDLINE | ID: mdl-27199460

ABSTRACT

After a cluster of fatal toxoplasmosis among stem cell transplant recipients at 2 hospitals, surveillance with polymerase chain reaction (PCR) (blood) was instituted. Rate of reactivation among seropositive recipients was 2.2 and 16%. Parasitemia was successfully managed with preemptive treatment. For seropositive recipients unable to take prophylaxis, toxoplasma PCR surveillance should be routinely performed.


Subject(s)
Pre-Exposure Prophylaxis , Stem Cell Transplantation/adverse effects , Toxoplasma/isolation & purification , Toxoplasmosis/epidemiology , Aged , Aged, 80 and over , Early Diagnosis , Epidemiological Monitoring , Female , Humans , Male , Middle Aged , New York City/epidemiology , Parasitemia , Polymerase Chain Reaction , Toxoplasma/genetics , Toxoplasmosis/diagnosis , Toxoplasmosis/mortality , Toxoplasmosis/parasitology , Transplant Recipients
16.
Biol Blood Marrow Transplant ; 22(1): 174-8, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26318614

ABSTRACT

Adenovirus (ADV) infections after hematopoietic cell transplantation (HCT) range in severity from self-limited to fatal. We have previously reported high mortality rates in CD34(+) selected T cell-depleted (TCD) HCT recipients using symptomatic testing and culture methods for ADV detection. We report rates and outcomes of ADV viremia in 215 adult recipients of TCD HCT using the CliniMACS CD34(+) selection system. This was a prospective observational study of adults transplanted from March 21, 2012 through November 30, 2014 at Memorial Sloan-Kettering Cancer Center. TCD was performed using CliniMACS CD34(+) cell selection. Patients were monitored for ADV by whole blood PCR assay from +14 to +100 days post-transplant. ADV viremia was defined as ≥1 PCR above the lower limit of quantitation. ADV disease was defined per European Group for Blood and Marrow Transplantation guidelines. Treatment for ADV was at the clinician's discretion. Competing risk regression analyses were used to identify predictors for ADV viremia and overall survival. The median age was 55 years (range, 22 to 72); 215 patients underwent TCD. All patients received myeloablative conditioning. Eighteen patients (8% of cohort) had ADV viremia at a median onset of 57 days (interquartile range [IQR], 23 to 79) and with a median viral load at first detection of 2.6 log10 copies/mL (IQR, 2.5 to 4.0). The median maximal viral load was 4.5 log10 copies/mL (IQR, 3.5 to 5.9). No significant risk factor was identified for ADV viremia by univariate analysis. Six patients (3% of total cohort, 33% of viremic patients) developed ADV disease (3 colitis, 2 nephritis/cystitis, 1 pneumonitis). ADV viremia preceded onset of ADV disease a median of 11 days from the first positive quantitative PCR (range, +3 to +37) except in 1 patient with nephritis. Overall, 12 of 18 viremic patients (67%) received antiviral treatment (5 cidofovir only, 7 brincidofovir ± cidofovir). All patients with ADV disease were treated, and 6 patients were preemptively treated for ADV. Among the 18 viremic patients, 8 (44%) died during the study period, and, of those, 4 (22%) died of ADV. Early ADV viremia was infrequent (8%) among adult HCT recipients of CD34(+) selected allografts. Among viremic patients, rate of ADV disease was 33% and ADV attributable mortality was 22%. Further studies are needed to assess the impact of preemptive treatment with brincidofovir on improving outcomes of ADV infections in this patient population.


Subject(s)
Adenoviridae Infections , Adenoviridae , Antigens, CD34 , Hematologic Neoplasms , Hematopoietic Stem Cell Transplantation , Viremia , Adenoviridae Infections/etiology , Adenoviridae Infections/mortality , Adult , Aged , Cohort Studies , Databases, Factual , Disease-Free Survival , Female , Hematologic Neoplasms/mortality , Hematologic Neoplasms/therapy , Humans , Incidence , Male , Middle Aged , Survival Rate
17.
Biol Blood Marrow Transplant ; 22(8): 1480-1486, 2016 08.
Article in English | MEDLINE | ID: mdl-27178374

ABSTRACT

The effectiveness of preemptive treatment (PET) for cytomegalovirus (CMV) in recipients of ex vivo T cell-depleted (TCD) hematopoietic cell transplantation (HCT) by CD34(+) selection is not well defined. We analyzed 213 adults who received TCD-HCT at our institution from June 2010 through May 2014. Patients were monitored by a CMV quantitative PCR assay if recipient (R) or donor (D) were CMV seropositive. CMV viremia occurred early (median, 27 days after HCT) in 91 of 213 (42.7%) patients for a 180-day cumulative incidence of 84.5%, 61.8%, and 0 for R+/D+, R+/D-, and R-/D+ patients, respectively. CMV disease occurred in 5% of patients. In Cox regression analysis, R+/D+ status was associated with increased risk for CMV viremia compared with R+/D- (hazard ratio [HR], 1.79, 95% confidence interval [CI], 1.16 to 2.76, P = .01), whereas matched unrelated donor allograft was associated with decreased risk (HR, .62; 95% CI, .39 to .97, P = .04). Of 91 patients with CMV viremia, 52 (57%) had persistent viremia (>28 days duration). Time lag from detection of CMV viremia to PET was associated with incremental risk for persistent viremia (HR, 1.09; 95% CI, 1.01 to 1.18; P = .03). Overall, 166 of 213 (77.9%) patients were alive 1 year after HCT, with no difference between patients with and without CMV viremia or among the different CMV serostatus pairs (P = not significant). CMV viremia occurred in 70% of R + TCD-HCT. Delay in PET initiation was associated with persistent viremia. With PET, CMV R/D serostatus did not adversely impact survival in TCD-HCT on 1-year survival in the present cohort.


Subject(s)
Cytomegalovirus Infections/prevention & control , Hematopoietic Stem Cell Transplantation/adverse effects , Lymphocyte Depletion/methods , Premedication/methods , Adult , Aged , Antigens, CD34/analysis , Cohort Studies , Cytomegalovirus Infections/etiology , Cytomegalovirus Infections/mortality , Female , Hematopoietic Stem Cell Transplantation/methods , Hematopoietic Stem Cell Transplantation/mortality , Humans , Incidence , Male , Middle Aged , Retrospective Studies , Survival Analysis , T-Lymphocytes , Tissue Donors , Viremia , Young Adult
18.
Plant Biotechnol J ; 14(1): 284-98, 2016 Jan.
Article in English | MEDLINE | ID: mdl-25917508

ABSTRACT

Orchids exhibit a range of unique flower shapes and are a valuable ornamental crop. MADS-box transcription factors are key regulatory components in flower initiation and development. Changing the flower shape and flowering time can increase the value of the orchid in the ornamental horticulture industry. In this study, 28 MADS-box genes were identified from the transcriptome database of the model orchid Erycina pusilla. The full-length genomic sequences of these MADS-box genes were obtained from BAC clones. Of these, 27 were MIKC-type EpMADS (two truncated forms) and one was a type I EpMADS. Eleven EpMADS genes contained introns longer than 10 kb. Phylogenetic analysis classified the 24 MIKC(c) genes into nine subfamilies. Three specific protein motifs, AG, FUL and SVP, were identified and used to classify three subfamilies. The expression profile of each EpMADS gene correlated with its putative function. The phylogenetic analysis was highly correlated with the protein domain identification and gene expression results. Spatial expression of EpMADS6, EpMADS12 and EpMADS15 was strongly detected in the inflorescence meristem, floral bud and seed via in situ hybridization. The subcellular localization of the 28 EpMADS proteins was also investigated. Although EpMADS27 lacks a complete MADS-box domain, EpMADS27-YFP was localized in the nucleus. This characterization of the orchid MADS-box family genes provides useful information for both orchid breeding and studies of flowering and evolution.


Subject(s)
Gene Expression Profiling , MADS Domain Proteins/genetics , Multigene Family , Orchidaceae/genetics , Amino Acid Motifs , Amino Acid Sequence , Arabidopsis/genetics , Databases, Genetic , Exons/genetics , Flowers/genetics , Gene Expression Regulation, Plant , Genes, Plant , Introns/genetics , MADS Domain Proteins/chemistry , MADS Domain Proteins/metabolism , Nucleotide Motifs , Organ Specificity/genetics , Phylogeny , Protein Domains , Subcellular Fractions/metabolism
19.
Clin Infect Dis ; 61 Suppl 6: S652-61, 2015 Dec 01.
Article in English | MEDLINE | ID: mdl-26567284

ABSTRACT

BACKGROUND: The use of mold-active azoles for antifungal prophylaxis after allogeneic stem cell transplantation (SCT) is hindered by adverse events and drug-drug interactions. Higher doses of echinocandins administered intermittently may be an alternative in this setting. METHODS: This was a single-center, observational 5-year study to characterize the safety and efficacy of intermittent administration of high-dose intravenous micafungin (≥5 doses of ≥300 mg micafungin 2-3 times weekly) in patients with acute leukemia and allogeneic SCT recipients. RESULTS: A total of 104 patients (84 allogeneic SCT recipients and 20 patients with leukemia) received intermittent high-dose intravenous micafungin, 83 (79.8%) as prophylaxis. Large variability in the micafungin dosing regimen was observed; 78 (75%) patients received >75% of their course as 300 mg micafungin 3 times weekly. Liver function tests decreased from baseline to end of treatment (EOT; P < .001). Patients with normal baseline liver function (n = 55 [52%]) maintained similar enzyme levels throughout the study. For patients with abnormal baseline liver function (n = 49 [47%]), liver function tests significantly improved from baseline to EOT (P ≤ .005). Duration and/or micafungin dosing algorithms were not associated with liver toxicity at EOT. There were no significant changes in renal function, and infusion-related reactions or deaths were not observed. Five of 83 (6.0%) patients in the prophylaxis group developed a breakthrough fungal infection. CONCLUSIONS: In this largest cohort of patients to date, intermittent administration of high-dose micafungin was well tolerated, without any associated liver or renal function abnormalities, and may be considered an alternative antifungal prophylactic strategy. Prospective studies are needed to further validate these findings.


Subject(s)
Antifungal Agents/administration & dosage , Echinocandins/administration & dosage , Hematopoietic Stem Cell Transplantation , Leukemia , Lipopeptides/administration & dosage , Mycoses/prevention & control , Acute Disease , Administration, Intravenous , Adult , Aged , Antifungal Agents/adverse effects , Dose-Response Relationship, Drug , Drug Administration Schedule , Echinocandins/adverse effects , Female , Humans , Infusions, Intravenous , Kidney/physiopathology , Leukemia/complications , Leukemia/microbiology , Lipopeptides/adverse effects , Liver Function Tests , Male , Micafungin , Middle Aged , Mycoses/microbiology , Retrospective Studies , Young Adult
20.
BMC Plant Biol ; 15: 100, 2015 Apr 11.
Article in English | MEDLINE | ID: mdl-25886915

ABSTRACT

BACKGROUND: Key innovations have facilitated novel niche utilization, such as the movement of the algal predecessors of land plants into terrestrial habitats where drastic fluctuations in light intensity, ultraviolet radiation and water limitation required a number of adaptations. The NDH (NADH dehydrogenase-like) complex of Viridiplantae plastids participates in adapting the photosynthetic response to environmental stress, suggesting its involvement in the transition to terrestrial habitats. Although relatively rare, the loss or pseudogenization of plastid NDH genes is widely distributed across diverse lineages of photoautotrophic seed plants and mutants/transgenics lacking NDH function demonstrate little difference from wild type under non-stressed conditions. This study analyzes large transcriptomic and genomic datasets to evaluate the persistence and loss of NDH expression across plants. RESULTS: Nuclear expression profiles showed accretion of the NDH gene complement at key transitions in land plant evolution, such as the transition to land and at the base of the angiosperm lineage. While detection of transcripts for a selection of non-NDH, photosynthesis related proteins was independent of the state of NDH, coordinate, lineage-specific loss of plastid NDH genes and expression of nuclear-encoded NDH subunits was documented in Pinaceae, gnetophytes, Orchidaceae and Geraniales confirming the independent and complete loss of NDH in these diverse seed plant taxa. CONCLUSION: The broad phylogenetic distribution of NDH loss and the subtle phenotypes of mutants suggest that the NDH complex is of limited biological significance in contemporary plants. While NDH activity appears dispensable under favorable conditions, there were likely sufficiently frequent episodes of abiotic stress affecting terrestrial habitats to allow the retention of NDH activity. These findings reveal genetic factors influencing plant/environment interactions in a changing climate through 450 million years of land plant evolution.


Subject(s)
Chloroplast Proteins/genetics , Evolution, Molecular , Genome, Plant , Transcriptome , Viridiplantae/genetics , Cell Nucleus/genetics , Chloroplast Proteins/metabolism , Molecular Sequence Data , Phylogeny , Sequence Analysis, DNA , Viridiplantae/metabolism
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