scholarly journals Novel Virulence Gene and Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR) Multilocus Sequence Typing Scheme for Subtyping of the Major Serovars ofSalmonella entericasubsp.enterica

2011 ◽  
Vol 77 (6) ◽  
pp. 1946-1956 ◽  
Author(s):  
Fenyun Liu ◽  
Rodolphe Barrangou ◽  
Peter Gerner-Smidt ◽  
Efrain M. Ribot ◽  
Stephen J. Knabel ◽  
...  
Keyword(s):  
Multilocus Sequence Typing ◽  
Virulence Genes ◽  
Virulence Gene ◽  
The United States ◽  
Pulsed Field Gel Electrophoresis ◽  
The Novel ◽  
Important Food ◽  
Mlst Scheme ◽  
Food Borne ◽  
Short Palindromic Repeat

ABSTRACTSalmonella entericasubsp.entericais the leading cause of bacterial food-borne disease in the United States. Molecular subtyping methods are powerful tools for tracking the farm-to-fork spread of food-borne pathogens during outbreaks. In order to develop a novel multilocus sequence typing (MLST) scheme for subtyping the major serovars ofS. entericasubsp.enterica, the virulence genessseLandfimHand clustered regularly interspaced short palindromic repeat (CRISPR) loci were sequenced from 171 clinical isolates from nineSalmonellaserovars,Salmonellaserovars Typhimurium, Enteritidis, Newport, Heidelberg, Javiana, I 4,[5],12:i:−, Montevideo, Muenchen, and Saintpaul. The MLST scheme using only virulence genes was congruent with serotyping and identified epidemic clones but could not differentiate outbreaks. The addition of CRISPR sequences dramatically improved discriminatory power by differentiating individual outbreak strains/clones. Of particular note, the present MLST scheme provided better discrimination ofSalmonellaserovar Enteritidis strains than pulsed-field gel electrophoresis (PFGE). This method showed high epidemiologic concordance for all serovars screened except forSalmonellaserovar Muenchen. In conclusion, the novel MLST scheme described in the present study accurately differentiated outbreak strains/clones of the major serovars ofSalmonella, and therefore, it shows promise for subtyping this important food-borne pathogen during investigations of outbreaks.

scholarly journals Covid-19 and food security: Jeopardy management and posterity deliberations

2021 ◽  
Vol 10 (2) ◽  
pp. 01-05
Author(s):  
Augustine Owusu-Addo ◽  
Atianashie Miracle A ◽  
Chukwuma Chinaza Adaobi ◽  
Larissa Agbemelo-Tsomafo
Keyword(s):  
Food Processing ◽  
Respiratory Illness ◽  
The United States ◽  
The Novel ◽  
Food Handling ◽  
Global Pandemic ◽  
Food Borne ◽  
Novel Coronavirus ◽  
Food Borne Infections ◽  
Safety Guidelines

COVID-19, also known as the ‘novel coronavirus disease 2019’, is a respiratory illness and the causative pathogen is officially named as ‘SARS-CoV-2’. Infections with SARS-CoV-2 have now been amplified to a global pandemic – as of April 3, 2020, nearly 1,018,000 cases have been confirmed in more than 195 countries, including more than 300,000 cases within the United States. Public safety guidelines are followed worldwide to stop the spread of COVID-19 and stay healthy. Despite COVID-19 is a respiratory illness with mode of invasion through the respiratory tract, not the gastrointestinal tract, an average food consumer is anxious and concerned about the food safety. Could an individual catch the deadly contagious COVID-19 from groceries brought home from the supermarket – or from the next restaurant takeout order? This brief review elucidates the epidemiology and pathobiological mechanism(s) of SARS-CoV-2 and its implications in food-borne infections, transmission via food surfaces, food processing and food handling.

scholarly journals Retrospective Study of Listeria Monocytogenes Isolated in the Territory of Inner Eurasia from 1947 to 1999

Pathogens ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 184 ◽  
Author(s):  
Psareva ◽  
Egorova ◽  
Liskova ◽  
Razheva ◽  
Gladkova ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Listeria Monocytogenes ◽  
20Th Century ◽  
Multilocus Sequence Typing ◽  
Clonal Complex ◽  
Small Ruminants ◽  
Virulence Gene ◽  
Penicillin G ◽  
Allelic Variants ◽  
Mlst Scheme

Listeriosis is one of the most significant humans and animals foodborne infectious diseases. Here, we characterized 48 Listeria monocytogenes strains isolated in the territory of inner Eurasia during the second half of the 20th century. A total of 23 strains (52.3%) were susceptible to the nine antibiotics tested, 30.43%, 15.22%, and 8.7% were resistant penicillin G, ampicillin, and enrofloxacin, respectively. We applied the multilocus sequence typing (MLST) scheme to determine the phylogenetic positions of the strains. All but one strain belonged to the II phylogenetic lineage, and the majority of the strains belonged to one of the previously described clonal complexes (СCs). More than 60% of the strains belonged to the clonal complex CC7 that prevailed among all sources, including cattle (58%), small ruminants (64%), rodents (71%), and humans (50%). Further, CC7, CC101, and CC124 were found among human isolates. The MLST scheme was supplemented with virulence gene analysis. In total, eight inlA, six inlB, and six inlC allelic variants were found, and all but one strain carried one of the two inlE alleles. Most strains (62.5%) belonged to the same multivirulence locus sequence typing (MvLST) type, which includes CC7, inlA allele 4, inlB allele 14, inlC allele 6, and inlE allele 8.

scholarly journals Comparison of Virulence Gene Identification, Ribosomal Spacer PCR, and Pulsed-Field Gel Electrophoresis for Typing of Staphylococcus aureus Strains Isolated from Cases of Subclinical Bovine Mastitis in the United States

2016 ◽  
Vol 54 (7) ◽  
pp. 1871-1876 ◽  
Author(s):  
Pamela R. F. Adkins ◽  
John R. Middleton ◽  
Lawrence K. Fox
Keyword(s):  
United States ◽  
Staphylococcus Aureus ◽  
Gel Electrophoresis ◽  
Virulence Gene ◽  
The United States ◽  
Pulsed Field Gel Electrophoresis ◽  
Gene Identification ◽  
Content Type ◽  
Pulsed Field

Staphylococcus aureusis one of the most important pathogens causing contagious mastitis in dairy cattle worldwide. The objectives of this study were to determine if recently describedS. aureusgenotype B was present among previously characterized isolates from cases of bovine intramammary infection in the United States and to compare pulsed-field gel electrophoresis (PFGE) to the combination of ribosomal spacer PCR (RS-PCR) and virulence gene identification for typing ofS. aureusstrains. The hypothesis was that isolates that were previously characterized as contagious would be identified as genotype B and that the results of the two strain-typing methods would be comparable. Isolates were selected from a collection ofS. aureusisolates from eight dairy farms. Mammary quarter milk somatic cell count (SCC) andN-acetyl-β-d-gluconaminidase (NAGase) activity data were known and used to evaluate strain pathogenicity. RS-PCR was performed with conventional gel electrophoresis, and PCR was used for toxin gene identification. RS-PCR patterns were associated with a specific virulence gene pattern, as previously reported. Five RS-PCR banding patterns were identified. None of the isolates were characterized as genotype B. No association between RS-PCR types and milk SCC was found; however, NAGase activity was significantly higher in milk from mammary glands infected with RS-PCR banding type 1 (RSP type 1) than in milk from those infected with RSP type 2. The discriminatory power values were 1.0 and 0.46 for PFGE and RS-PCR, respectively. These data suggest that genotype B may have a limited geographic distribution and that PFGE is more discriminatory than RS-PCR performed with conventional gel electrophoresis for typing ofS. aureusisolates of bovine origin.

scholarly journals Determination of Molecular Phylogenetics of Vibrio parahaemolyticus Strains by Multilocus Sequence Typing

2008 ◽  
Vol 190 (8) ◽  
pp. 2831-2840 ◽  
Author(s):  
Narjol González-Escalona ◽  
Jaime Martinez-Urtaza ◽  
Jaime Romero ◽  
Romilio T. Espejo ◽  
Lee-Ann Jaykus ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Multilocus Sequence Typing ◽  
Vibrio Parahaemolyticus ◽  
Molecular Phylogenetics ◽  
Clonal Complex ◽  
Housekeeping Genes ◽  
The United States ◽  
Health Concern ◽  
Mlst Scheme

ABSTRACT Vibrio parahaemolyticus is an important human pathogen whose transmission is associated with the consumption of contaminated seafood. There is a growing public health concern due to the emergence of a pandemic strain causing severe outbreaks worldwide. Many questions remain unanswered regarding the evolution and population structure of V. parahaemolyticus. In this work, we describe a multilocus sequence typing (MLST) scheme for V. parahaemolyticus based on the internal fragment sequences of seven housekeeping genes. This MLST scheme was applied to 100 V. parahaemolyticus strains isolated from geographically diverse clinical (n = 37) and environmental (n = 63) sources. The sequences obtained from this work were deposited and are available in a public database (http://pubmlst.org/vparahaemolyticus ). Sixty-two unique sequence types were identified, and most (50) were represented by a single isolate, suggesting a high level of genetic diversity. Three major clonal complexes were identified by eBURST analysis. Separate clonal complexes were observed for V. parahaemolyticus isolates originating from the Pacific and Gulf coasts of the United States, while a third clonal complex consisted of strains belonging to the pandemic clonal complex with worldwide distribution. The data reported in this study indicate that V. parahaemolyticus is genetically diverse with a semiclonal population structure and an epidemic structure similar to that of Vibrio cholerae. Genetic diversity in V. parahaemolyticus appears to be driven primarily by frequent recombination rather than mutation, with recombination ratios estimated at 2.5:1 and 8.8:1 by allele and site, respectively. Application of this MLST scheme to more V. parahaemolyticus strains and by different laboratories will facilitate production of a global picture of the epidemiology and evolution of this pathogen.

scholarly journals Virulence Genes in Heterodera glycines: Allele Frequencies and Ror Gene Groups Among Field Isolates and Inbred Lines

2005 ◽  
Vol 95 (2) ◽  
pp. 186-191 ◽  
Author(s):  
K. Dong ◽  
K. R. Barker ◽  
C. H. Opperman
Keyword(s):  
Virulence Genes ◽  
Heterodera Glycines ◽  
Dominant Gene ◽  
Virulence Gene ◽  
The United States ◽  
Allele Frequencies ◽  
Soybean Plant ◽  
Single Female ◽  
Field Isolates ◽  
Genotype Frequencies

Genetic variation in field populations of Heterodera glycines is a key issue for both resistance gene deployment and basic understanding of virulence-gene flow in populations. In this study, we examined phenotypically defined genes for virulence under selection from host resistance. We separated the most common H. glycines genotypes in the United States into two virulence groups, based on their reproductive abilities on the resistant soybean plant introduction (PI) 88788. These groups correspond to previously identified virulence genes in the nematode, as follows: the dominant gene in H. glycines to PI88788, and the recessive genes to PI90763 and Pickett/Peking. Virulence allele frequencies and virulence genotype frequencies of selected field isolates were investigated by testing the host range of single-female-derived lines, which were developed through single-female inoculation on the standard susceptible soybean ‘Lee 68’. By comparing virulence genotype frequencies between the original field isolates and their single-female-derived lines, we were able to determine allele frequencies in the field populations. The results suggest that tremendous variation in H. glycines virulence genes exists among field populations. Potential mechanisms of selection which could cause virulence genotype frequency increases are discussed as related to population genetics equilibrium theory.

scholarly journals Comparative Genomic and Morphological Analyses of Listeria Phages Isolated from Farm Environments

2014 ◽  
Vol 80 (15) ◽  
pp. 4616-4625 ◽  
Author(s):  
Thomas Denes ◽  
Kitiya Vongkamjan ◽  
Hans-Wolfgang Ackermann ◽  
Andrea I. Moreno Switt ◽  
Martin Wiedmann ◽  
...  
Keyword(s):  
New York ◽  
Dairy Farm ◽  
Morphological Diversity ◽  
Genomic Diversity ◽  
Comparative Genomic ◽  
The Novel ◽  
Important Food ◽  
Content Type ◽  
Small Genome ◽  
Food Borne

ABSTRACTThe genusListeriais ubiquitous in the environment and includes the globally important food-borne pathogenListeria monocytogenes. While the genomic diversity ofListeriahas been well studied, considerably less is known about the genomic and morphological diversity ofListeriabacteriophages. In this study, we sequenced and analyzed the genomes of 14Listeriaphages isolated mostly from New York dairy farm environments as well as one relatedEnterococcus faecalisphage to obtain information on genome characteristics and diversity. We also examined 12 of the phages by electron microscopy to characterize their morphology. TheseListeriaphages, based on gene orthology and morphology, together with previously sequencedListeriaphages could be classified into five orthoclusters, including one novel orthocluster. One orthocluster (orthocluster I) consists of large-genome (∼135-kb) myoviruses belonging to the genus “Twort-like viruses,” three orthoclusters (orthoclusters II to IV) contain small-genome (36- to 43-kb) siphoviruses with icosahedral heads, and the novel orthocluster V contains medium-sized-genome (∼66-kb) siphoviruses with elongated heads. A novel orthocluster (orthocluster VI) ofE. faecalisphages, with medium-sized genomes (∼56 kb), was identified, which grouped together and shares morphological features with the novelListeriaphage orthocluster V. This new group of phages (i.e., orthoclusters V and VI) is composed of putative lytic phages that may prove to be useful in phage-based applications for biocontrol, detection, and therapeutic purposes.

scholarly journals Multilocus Sequence Typing Reveals Two Evolutionary Lineages of Acidovorax avenae subsp. citrulli

2009 ◽  
Vol 99 (8) ◽  
pp. 913-920 ◽  
Author(s):  
Jianjun Feng ◽  
Erin L. Schuenzel ◽  
Jianqiang Li ◽  
Norman W. Schaad
Keyword(s):  
United States ◽  
Multilocus Sequence Typing ◽  
The United States ◽  
Causal Agent ◽  
Reliable Identification ◽  
Bacterial Fruit Blotch ◽  
Mlst Scheme ◽  
Evolutionary Lineages ◽  
Considerable Damage

Acidovorax avenae subsp. citrulli, causal agent of bacterial fruit blotch, has caused considerable damage to the watermelon and melon industry in China and the United States. Understanding the emergence and spread of this pathogen is important for controlling the disease. To build a fingerprinting database for reliable identification and tracking of strains of A. avenae subsp. citrulli, a multilocus sequence typing (MLST) scheme was developed using seven conserved loci. The study included 8 original strains from the 1978 description of A. avenae subsp. citrulli, 51 from China, and 34 from worldwide collections. Two major clonal complexes (CCs), CC1 and CC2, were identified within A. avenae subsp. citrulli; 48 strains typed as CC1 and 45 as CC2. All eight original 1978 strains isolated from watermelon and melon grouped in CC1. CC2 strains were predominant in the worldwide collection and all but five were isolated from watermelon. In China, a major seed producer for melon and watermelon, the predominant strains were CC1 and were found nearly equally on melon and watermelon.

scholarly journals Subtyping Salmonella enterica Serovar Enteritidis Isolates from Different Sources by Using Sequence Typing Based on Virulence Genes and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPRs)

2011 ◽  
Vol 77 (13) ◽  
pp. 4520-4526 ◽  
Author(s):  
Fenyun Liu ◽  
Subhashinie Kariyawasam ◽  
Bhushan M. Jayarao ◽  
Rodolphe Barrangou ◽  
Peter Gerner-Smidt ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Virulence Genes ◽  
Food System ◽  
The United States ◽  
Clinical Isolates ◽  
Salmonella Enterica Serovar Enteritidis ◽  
Specific Sequence ◽  
Content Type ◽  
System A ◽  
Food Borne

ABSTRACTSalmonella entericasubsp.entericaserovar Enteritidis is a major cause of food-borne salmonellosis in the United States. Two major food vehicles forS. Enteritidis are contaminated eggs and chicken meat. Improved subtyping methods are needed to accurately track specific strains ofS. Enteritidis related to human salmonellosis throughout the chicken and egg food system. A sequence typing scheme based on virulence genes (fimHandsseL) and clustered regularly interspaced short palindromic repeats (CRISPRs)—CRISPR-including multi-virulence-locus sequence typing (designated CRISPR-MVLST)—was used to characterize 35 human clinical isolates, 46 chicken isolates, 24 egg isolates, and 63 hen house environment isolates ofS. Enteritidis. A total of 27 sequence types (STs) were identified among the 167 isolates. CRISPR-MVLST identified three persistent and predominate STs circulating among U.S. human clinical isolates and chicken, egg, and hen house environmental isolates in Pennsylvania, and an ST that was found only in eggs and humans. It also identified a potential environment-specific sequence type. Moreover, cluster analysis based onfimHandsseLidentified a number of clusters, of which several were found in more than one outbreak, as well as 11 singletons. Further research is needed to determine if CRISPR-MVLST might help identify the ecological origins ofS. Enteritidis strains that contaminate chickens and eggs.

scholarly journals Characterization of genetic diversity and population structure within Staphylococcus chromogenes by multilocus sequence typing

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0243688
Author(s):  
Rebeca Huebner ◽  
Robert Mugabi ◽  
Gabriella Hetesy ◽  
Lawrence Fox ◽  
Sarne De Vliegher ◽  
...  
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Multilocus Sequence Typing ◽  
Bovine Mastitis ◽  
The United States ◽  
Genetic Lineage ◽  
Single Nucleotide Variants ◽  
Discrimination Power ◽  
Core Group ◽  
Mlst Scheme

Staphylococcus chromogenes is a common skin commensal in cattle and has been identified as a frequent cause of bovine mastitis and intramammary infections. We have developed a seven locus Multilocus Sequence Typing (MLST) scheme for typing S. chromogenes. Sequence-based typing systems, such as MLST, have application in studies of genetic diversity, population structure, and epidemiology, including studies of strain variation as a factor in pathogenicity or host adaptation. The S. chromogenes scheme was tested on 120 isolates collected from three geographic locations, Vermont and Washington State in the United States and Belgium. A total of 46 sequence types (STs) were identified with most of the STs being location specific. The utility of the typing scheme is indicated by a discrimination power of 95.6% for all isolates and greater than 90% for isolates from each of the three locations. Phylogenetic analysis placed 39 of the 46 STs into single core group consistent with a common genetic lineage; the STs in this group differ by less than 0.5% at the nucleotide sequence level. Most of the diversification in this lineage group can be attributed to mutation; recombination plays a limited role. This lineage group includes two clusters of single nucleotide variants in starburst configurations indicative of recent clonal expansion; nearly 50% of the isolates sampled in this study are in these two clusters. The remaining seven STs were set apart from the core group by having alleles with highly variable sequences at one or more loci. Recombination had a higher impact than mutation in the diversification of these outlier STs. Alleles with hypervariable sequences were detected at five of the seven loci used in the MLST scheme; the average sequence distances between the hypervariable alleles and the common core alleles ranged from 12 to 34 nucleotides. The extent of these sequence differences suggests the hypervariable alleles may be remnants of an ancestral genotype.

scholarly journals ­­­Characterization of integrated prophages within diverse species of clinical nontuberculous mycobacteria

2020 ◽  
Author(s):  
Cody Glickman ◽  
Sara M. Kammlade ◽  
Nabeeh A. Hasan ◽  
L. Elaine Epperson ◽  
Rebecca M. Davidson ◽  
...  
Keyword(s):  
Growth Rate ◽  
Virulence Genes ◽  
Gene Annotation ◽  
Virulence Gene ◽  
Selective Advantage ◽  
The United States ◽  
Bacterial Virulence ◽  
Clinical Samples ◽  
Clinical Environment ◽  
Genetic Elements

Abstract Background Nontuberculous mycobacterial (NTM) infections are increasing in prevalence, with current estimates suggesting that over 100,000 people in the United States are affected each year. It is unclear how certain species of mycobacteria transition from environmental bacteria to clinical pathogens, or what genetic elements influence the differences in virulence among strains of the same species. A potential mechanism of genetic evolution and diversity within mycobacteria is the presence of integrated viruses called prophages in the host genome. Prophages may act as carriers of bacterial genes, with the potential of altering bacterial fitness through horizontal gene transfer. In this study, we quantify the frequency and composition of prophages within mycobacteria isolated from clinical samples and compare them against the composition of PhagesDB, an environmental mycobacteriophage database. Methods Prophages were predicted by agreement between two discovery tools, VirSorter and Phaster, and the frequencies of integrated prophages were compared by growth rate. Prophages were assigned to PhagesDB lettered clusters. Bacterial virulence gene frequency was calculated using a combination of the Virulence Factor Database (VFDB) and the Pathosystems Resource Integration Center virulence database (Patric-VF) within the gene annotation software Prokka. CRISPR elements were discovered using CRT. ARAGORN was used to quantify tRNAs. Results Rapidly growing mycobacteria (RGM) were more likely to contain prophage than slowly growing mycobacteria (SGM). CRISPR elements were not associated with prophage abundance in mycobacteria. The abundance of tRNAs was enriched in SGM compared to RGM. We compared the abundance of bacterial virulence genes within prophage genomes from clinical isolates to mycobacteriophages from PhagesDB. Our data suggests that prophages from clinical mycobacteria are enriched for bacterial virulence genes relative to environmental mycobacteriophage from PhagesDB. Conclusion Prophages are present in clinical NTM isolates. Prophages are more likely to be present in RGM compared to SGM genomes. The mechanism and selective advantage of this enrichment by growth rate remain unclear. In addition, the frequency of bacterial virulence genes in prophages from clinical NTM is enriched relative to the PhagesDB environmental proxy. This suggests prophages may act as a reservoir of genetic elements bacteria could use to thrive within a clinical environment.

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