domingo, 1 de marzo de 2015

Epidemiology and Molecular Characterization of Cryptosporidium spp.... - PubMed - NCBI

2015 Feb 20;9(2):e0003529. doi: 10.1371/journal.pntd.0003529. eCollection 2015.

Epidemiology and Molecular Characterization of Cryptosporidium spp. in Humans, Wild Primates, and Domesticated Animals in the Greater Gombe Ecosystem, Tanzania.

Parsons MB1, Travis D2, Lonsdorf EV3, Lipende I4, Roellig DM5, Kamenya S4, Zhang H6, Xiao L7, Gillespie TR8.

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Abstract

Cryptosporidium is an important zoonotic parasite globally. Few studies have examined the ecology and epidemiology of this pathogen in rural tropical systems characterized by high rates of overlap among humans, domesticated animals, and wildlife. We investigated risk factors for Cryptosporidium infection and assessed cross-species transmission potential among people, non-human primates, and domestic animals in the Gombe Ecosystem, Kigoma District, Tanzania. A cross-sectional survey was designed to determine the occurrence and risk factors for Cryptosporidium infection in humans, domestic animals and wildlife living in and around Gombe National Park. Diagnostic PCR revealed Cryptosporidium infection rates of 4.3% in humans, 16.0% in non-human primates, and 9.6% in livestock. Local streams sampled were negative. DNA sequencing uncovered a complex epidemiology for Cryptosporidium in this system, with humans, baboons and a subset of chimpanzees infected with C. hominis subtype IfA12G2; another subset of chimpanzees infected with C. suis; and all positive goats and sheep infected with C. xiaoi. For humans, residence location was associated with increased risk of infection in Mwamgongo village compared to one camp (Kasekela), and there was an increased odds for infection when living in a household with another positive person. Fecal consistency and other gastrointestinal signs did not predict Cryptosporidium infection. Despite a high degree of habitat overlap between village people and livestock, our results suggest that there are distinct Cryptosporidium transmission dynamics for humans and livestock in this system. The dominance of C. hominis subtype IfA12G2 among humans and non-human primates suggest cross-species transmission. Interestingly, a subset of chimpanzees was infected with C. suis. We hypothesize that there is cross-species transmission from bush pigs (Potaochoerus larvatus) to chimpanzees in Gombe forest, since domesticated pigs are regionally absent. Our findings demonstrate a complex nature of Cryptosporidium in sympatric primates, including humans, and stress the need for further studies.

PMID:: 25700265; [PubMed - in process]
PMCID:: PMC4336292

Free PMC Article

Whole genome detection of rotavirus mixed infections in human, porc... - PubMed - NCBI

2015 Feb 17. pii: S1567-1348(15)00054-4. doi: 10.1016/j.meegid.2015.02.011. [Epub ahead of print]

Whole genome detection of rotavirus mixed infections in human, porcine and bovine samples co-infected with various rotavirus strains collected from sub-Saharan Africa.

Nyaga MM1, Jere KC2, Esona MD3, Seheri ML4, Stucker KM5, Halpin RA6, Akopov A7, Stockwell TB8, Peenze I9, Diop A10, Ndiaye K11, Boula A12, Maphalala G13, Berejena C14, Mwenda JM15, Steele AD16, Wentworth DE17, Mphahlele MJ18.

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Abstract

Group A rotaviruses (RVA) are among the main global causes of severe diarrhea in children under the age of 5years. Strain diversity, mixed infections and untypeable RVA strains are frequently reported in Africa. We analysed rotavirus-positive human stool samples (n=13) obtained from hospitalised children under the age of 5years who presented with acute gastroenteritis at sentinel hospital sites in six African countries, as well as bovine and porcine stool samples (n=1 each), to gain insights into rotavirus diversity and evolution. Polyacrylamide gel electrophoresis (PAGE) analysis and genotyping with G-(VP7) and P-specific (VP4) typing primers suggested that 13 of the 15 samples contained more than 11 segments and/or mixed G/P genotypes. Full-length amplicons for each segment were generated using RVA-specific primers and sequenced using the Ion Torrent and/or Illumina MiSeq next-generation sequencing platforms. Sequencing detected at least one segment in each sample for which duplicate sequences, often having distinct genotypes, existed. This supported and extended the PAGE and RT-PCR genotyping findings that suggested these samples were collected from individuals that had mixed rotavirus infections. The study reports the first porcine (MRC-DPRU1567) and bovine (MRC-DPRU3010) mixed infections. We also report a unique genome segment 9 (VP7), whose G9 genotype belongs to lineage VI and clusters with porcine reference strains. Previously, African G9 strains have all been in lineage III. Furthermore, additional RVA segments isolated from humans have a clear evolutionary relationship with porcine, bovine and ovine rotavirus sequences, indicating relatively recent interspecies transmission and reassortment. Thus, multiple RVA strains from sub-Saharan Africa are infecting mammalian hosts with unpredictable variations in their gene segment combinations. Whole-genome sequence analyses of mixed RVA strains underscore the considerable diversity of rotavirus sequences and genome segment combinations that result from a complex evolutionary history involving multiple host species.

KEYWORDS:

Africa; Mixed infections; Reassortants; Rotavirus; Whole genome

PMID:: 25701122; [PubMed - as supplied by publisher]

Prevalence and genetic characteristics of Cryptosporidium, Enterocy... - PubMed - NCBI

2015 Jan 28. pii: S0304-4017(15)00032-1. doi: 10.1016/j.vetpar.2015.01.014. [Epub ahead of print]

Prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi and Giardia duodenalis in cats and dogs in Heilongjiang province, China.

Li W1, Li Y2, Song M2, Lu Y2, Yang J2, Tao W2, Jiang Y2, Wan Q2, Zhang S2, Xiao L3.

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Abstract

This study investigated 319 fecal specimens of cats (n=52) and dogs (n=267) from Heilongjiang province, China for the prevalence and genetic characteristics of Cryptosporidium, Enterocytozoon bieneusi, and Giardia duodenalis. PCR and DNA sequence analysis of the small subunit rRNA gene identified C. felis and C. parvum in one cat each (3.8%) and C. canis and C. ubiquitum in 6 dogs (2.2%). Polymorphisms in the ribosomal internal transcribed spacer and phylogenetic analysis characterized zoonotic E. bieneusi genotypes D, EbpC, NED1, and NED2 and host-adapted ones NED3, NED4, and PtEb IX in 18 dogs (6.7%) and human-pathogenic genotypes D and IV in 3 cats (5.8%). Genotyping based on the hypermutation of G. duodenalis triosephosphate isomerase gene (TPI) facilitated identification of assemblage F in a cat (1.9%) and assemblages C and E in 12 dogs (4.5%). Subtypes of G. duodenalis isolates were determined by measuring the diversity of both TPI nucleotide and amino acid sequences. C. canis, C. felis, C. parvum, E. bieneusi genotypes D, EbpC, and IV, and G. duodenalis assemblage C identified herein have been documented in human infections in China. C. canis, C. parvum, C. ubiquitum, and E. bieneusi genotypes D, EbpC, and IV carried by cats or dogs also existed in wastewater in China. The finding suggested pet animals could be reservoirs for human cryptosporidiosis, microsporidiosis, and giardiasis and potential sources of water contamination in China.

KEYWORDS:

Cryptosporidium; Enterocytozoon bieneusi; Genotyping; Giardia duodenalis; Subtyping

PMID:: 25665462; [PubMed - as supplied by publisher]

Phenotypic and phylogenetic analysis of Vibrio parahaemolyticus iso... - PubMed - NCBI

2015 Jan 19;200C:13-17. doi: 10.1016/j.ijfoodmicro.2014.12.009. [Epub ahead of print]

Phenotypic and phylogenetic analysis of Vibrio parahaemolyticus isolates recovered from diarrhea cases in Guangdong Province, China.

Li B1, Luo J2, Tan H1, Ke B1, He D1, Ke C1, Klena JD3, Zhang Y4.

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Abstract

Vibrio parahaemolyticus has emerged as a common foodborne pathogen of global concern. In this study, 108 V. parahaemolyticus isolates that recovered from diarrhea cases (n=96) and seafood products (n=12) in Guangdong Province from 2007 to 2011 were characterized by serotyping, tdh and trh toxin gene detection and multilocus sequence typing (MLST). The dominant serotypes from the cases were O3:K6, O4:K8 and O1: KUT (untyped). However, most isolates recovered from seafood products belonged to other serotypes. None of the isolates carried the trh gene, while the major isolates from the cases were tdh positive. MLST analysis revealed 31 sequence types (STs); 17 STs were unique in this study. eBURST analysis revealed four clonal complexes (CC), The majority of the isolates (n=58, all from cases and tdh+) were grouped into the CC3, which included O3:K6, O4:K68 and O1:KUT isolates. The CC3 was the most prevalent clonal complex, and all of the CC3 isolates were recovered from clinical cases of geographically diverse origin. As to the CC345, which was completely constituted by O4:K8, was another important clonal complex affecting Guangdong Province. Ongoing surveillance of V. parahaemolyticus in diarrhea patients and seafood products remains a public health priority for Guangdong Province, China.

KEYWORDS:

Multilocus sequence typing; Phylogenetic analysis; Vibrio parahaemolyticus

PMID:: 25662708; [PubMed - as supplied by publisher]

Examination of genetic variants involved in generation and biodispo... - PubMed - NCBI

2014 Dec 12;10(1):60. doi: 10.1186/s13223-014-0060-y. eCollection 2014.

Examination of genetic variants involved in generation and biodisposition of kinins in patients with angioedema.

Levy J1, Rivard GE2, Wagner E3, Beezhold D4, Berlin N5, Fan L2, Zhang Z2, Sussman GL5.

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Abstract

BACKGROUND:

Angioedema (AE) is idiopathic in the majority of cases. We studied patients with AE for genetic variants of proteins involved with bradykinin generation and biodisposition.

METHODS:

One hundred sixty one patients with AE were recruited at a university hospital clinic. Patients were categorized according to the proposed pathogenesis of AE: low C1 inhibitor (C1-INH) and C4 levels, autoimmune disease, cancer, angiotensin-converting enzyme (ACE) inhibitor-induced, nonsteroidal antiinflammatory drug (NSAID)-induced, or idiopathic. In addition, each patient had a blood sample analyzed for a complement profile and enzymes (C1-INH and C4). Fifty-two of the patients were tested for genetic variants in factor XII, plasminogen-activator inhibitor-1 (PAI-1), ACE, and aminopeptidase P (APP).

RESULTS:

The cause of angioedema was identified in 59/161 (37%) of the cases: 3 (2%) patients had a low plasma C1-INH and C4; 20 (12%) were ACE inhibitor-induced; 12 (7%) were associated with autoimmune disorders; 7 (4%) were associated with malignancy; and 17 (11%) were associated with NSAIDs. In the remaining 102 (63%) patients the cause of angioedema was idiopathic. Of 52 patients with genetic analysis, 13 (25%) had a genetic variant in APP, 10 (19%) in ACE, 13 (25%) in PAI-1, and 0 in Factor XII.

CONCLUSIONS:

In addition to related diseases and medications causing AE, certain genetic variants encoding proteins involved in bradykinin generation and/or catabolism pathways may be involved in the pathogenesis of AE.

KEYWORDS:

Aminopeptidase P; Angioedema; Angiotensin-converting enzyme; Factor XII; Plasminogen-activator inhibitor-1

PMID:: 25670937; [PubMed]
PMCID:: PMC4323216

Free PMC Article

Isolation and Functional Characterization of the Novel Clostridium ... - PubMed - NCBI

2015 Feb 6;10(2):e0116381. doi: 10.1371/journal.pone.0116381. eCollection 2015.

Isolation and Functional Characterization of the Novel Clostridium botulinum Neurotoxin A8 Subtype.

Kull S1, Schulz KM1, Strotmeier JW2, Kirchner S1, Schreiber T1, Bollenbach A2, Dabrowski PW3, Nitsche A3, Kalb SR4, Dorner MB1, Barr JR4, Rummel A2,Dorner BG1.

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Abstract

Botulism is a severe neurological disease caused by the complex family of botulinum neurotoxins (BoNT). Based on the different serotypes known today, a classification of serotype variants termed subtypes has been proposed according to sequence diversity and immunological properties. However, the relevance of BoNT subtypes is currently not well understood. Here we describe the isolation of a novel Clostridium botulinum strain from a food-borne botulism outbreak near Chemnitz, Germany. Comparison of its botulinum neurotoxin gene sequence with published sequences identified it to be a novel subtype within the BoNT/A serotype designated BoNT/A8. The neurotoxin gene is located within an ha-orfX+ cluster and showed highest homology to BoNT/A1, A2, A5, and A6. Unexpectedly, we found an arginine insertion located in the HC domain of the heavy chain, which is unique compared to all other BoNT/A subtypes known so far. Functional characterization revealed that the binding characteristics to its main neuronal protein receptor SV2C seemed unaffected, whereas binding to membrane-incorporated gangliosides was reduced in comparison to BoNT/A1. Moreover, we found significantly lower enzymatic activity of the natural, full-length neurotoxin and the recombinant light chain of BoNT/A8 compared to BoNT/A1 in different endopeptidase assays. Both reduced ganglioside binding and enzymatic activity may contribute to the considerably lower biological activity of BoNT/A8 as measured in a mouse phrenic nerve hemidiaphragm assay. Despite its reduced activity the novel BoNT/A8 subtype caused severe botulism in a 63-year-old male. To our knowledge, this is the first description and a comprehensive characterization of a novel BoNT/A subtype which combines genetic information on the neurotoxin gene cluster with an in-depth functional analysis using different technical approaches. Our results show that subtyping of BoNT is highly relevant and that understanding of the detailed toxin function might pave the way for the development of novel therapeutics and tailor-made antitoxins.

PMID:: 25658638; [PubMed - in process]
PMCID:: PMC4320087

Free PMC Article

Clinical exome sequencing for genetic identification of rare Mendel... - PubMed - NCBI

2014 Nov 12;312(18):1880-7. doi: 10.1001/jama.2014.14604.

Clinical exome sequencing for genetic identification of rare Mendelian disorders.

Lee H1, Deignan JL1, Dorrani N2, Strom SP1, Kantarci S1, Quintero-Rivera F1, Das K1, Toy T1, Harry B3, Yourshaw M4, Fox M4, Fogel BL5, Martinez-Agosto JA6, Wong DA4, Chang VY4, Shieh PB5, Palmer CG7, Dipple KM6, Grody WW8, Vilain E9, Nelson SF10.

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Abstract

IMPORTANCE:

Clinical exome sequencing (CES) is rapidly becoming a common molecular diagnostic test for individuals with rare genetic disorders.

OBJECTIVE:

To report on initial clinical indications for CES referrals and molecular diagnostic rates for different indications and for different test types.

DESIGN, SETTING, AND PARTICIPANTS:

Clinical exome sequencing was performed on 814 consecutive patients with undiagnosed, suspected genetic conditions at the University of California, Los Angeles, Clinical Genomics Center between January 2012 and August 2014. Clinical exome sequencing was conducted as trio-CES (both parents and their affected child sequenced simultaneously) to effectively detect de novo and compound heterozygous variants or as proband-CES (only the affected individual sequenced) when parental samples were not available.

MAIN OUTCOMES AND MEASURES:

Clinical indications for CES requests, molecular diagnostic rates of CES overall and for phenotypic subgroups, and differences in molecular diagnostic rates between trio-CES and proband-CES.

RESULTS:

Of the 814 cases, the overall molecular diagnosis rate was 26% (213 of 814; 95% CI, 23%-29%). The molecular diagnosis rate for trio-CES was 31% (127 of 410 cases; 95% CI, 27%-36%) and 22% (74 of 338 cases; 95% CI, 18%-27%) for proband-CES. In cases of developmental delay in children (<5 years, n = 138), the molecular diagnosis rate was 41% (45 of 109; 95% CI, 32%-51%) for trio-CES cases and 9% (2 of 23, 95% CI, 1%-28%) for proband-CES cases. The significantly higher diagnostic yield (P value = .002; odds ratio, 7.4 [95% CI, 1.6-33.1]) of trio-CES was due to the identification of de novo and compound heterozygous variants.

CONCLUSIONS AND RELEVANCE:

In this sample of patients with undiagnosed, suspected genetic conditions, trio-CES was associated with higher molecular diagnostic yield than proband-CES or traditional molecular diagnostic methods. Additional studies designed to validate these findings and to explore the effect of this approach on clinical and economic outcomes are warranted.