Genome typing and epidemiology of human listeriosis in New Zealand 1999-2018

Author(s):  
Lucia Rivas ◽  
Shevaun Paine ◽  
Pierre-Yves Dupont ◽  
Audrey Tiong ◽  
Beverley Horn ◽  
...  

This study describes the epidemiology of listeriosis in New Zealand (NZ) between 1999 and 2018, as well as the retrospective whole genome sequencing (WGS) of 453 Listeria monocytogenes isolates corresponding to 95% of the human cases within this period. The average notified rate of listeriosis was 0.5 cases per 100,000 population and non-pregnancy associated cases were more prevalent than pregnancy-associated cases (average 19 and 5 cases per annum, respectively). Analysis of WGS data was assessed using multi-locus sequencing typing (MLST), including core-genome and whole-genome MLST (cgMLST and wgMLST) and single-nucleotide polymorphism (SNP) analysis. Thirty-nine sequence types (STs) were identified, with the most common being, ST1 (21.9%), ST4 (13.2%), ST2 (11.3%), ST120 (6.1%) and ST155 (6.4%). A total of 291 different cgMLST types were identified, with the majority (n = 243) of types observed as a single isolate, consistent with the observation that listeriosis is predominately sporadic. Amongst the 49 cgMLST types containing two or more isolates, 18 cgMLST types contained 2-4 isolates (50 isolates in total, including three outbreak-associated isolates) that shared low genetic diversity (0-2 whole-genome alleles), some of which were dispersed in time or geographical regions. SNP-analysis also produced comparable results to wgMLST. The low genetic diversity within these clusters suggests a potential common source but incomplete epidemiological data impaired retrospective epidemiological investigations. Prospective use of WGS analysis, together with thorough exposure information from cases will potentially identify future outbreaks more rapidly and possibly those that have been undetected for some time over different geographically regions.

2007 ◽  
Vol 81 (23) ◽  
pp. 12758-12765 ◽  
Author(s):  
Vladimir N. Loparev ◽  
Elena N. Rubtcova ◽  
Vanda Bostik ◽  
Dhwani Govil ◽  
Christopher J. Birch ◽  
...  

ABSTRACT Whole genome phylogenetic analysis in this study resolved a total of five major genotypes among the 22 varicella-zoster virus (VZV) strains or isolates for which complete genomic sequences are available. Consistent with earlier publications we have designated these genotypes European 1 (E1), European 2 (E2), Japanese (J), mosaic 1 (M1), and mosaic 2 (M2). Single nucleotide polymorphism (SNP) analysis performed in a whole-genome alignment revealed that VZV isolates of all five genotypes can be accurately genotyped using SNPs from two amplicons: open reading frame 22 (ORF22) and either ORF21 or ORF50. This modified approach identifies all of the genotypes observed using any of the published genotyping protocols. Of 165 clinical varicella and zoster isolates from Australia and New Zealand typed using this approach, 67 of 127 eastern Australian isolates were E1, 30 were E2, 16 were J, 10 were M1, and 4 were M2; 25 of 38 New Zealand isolates were E1, 8 were E2, and 5 were M1. VZV strain diversity in eastern Australia is thus broader than has been described for any other region, including Europe, Africa, and North America. J strains were far more prevalent than previously observed in countries other than Japan. Two-amplicon typing was in complete accord with genotypes derived using SNP in multiple ORFs (ORFs 1, 21, 22, 38, 50, 54, and 62). Two additional minor genotypes, M3 and M4, could also be resolved using two-amplicon typing.


Author(s):  
A Baktash ◽  
J Corver ◽  
C Harmanus ◽  
W. K. Smits ◽  
W Fawley ◽  
...  

Clostridioides difficile is the most common cause of antibiotic-associated gastrointestinal infections. Capillary-electrophoresis (CE)-PCR ribotyping is currently the gold standard for C. difficile typing but lacks discriminatory power to study transmission and outbreaks in detail. New molecular methods have the capacity to differentiate better and provide standardized and interlaboratory exchangeable data. Using a well-characterized collection of diverse strains (N=630; 100 unique ribotypes (RTs)), we compared the discriminatory power of core genome multilocus sequence typing (cgMLST) (SeqSphere & EnteroBase), whole genome MLST (wgMLST) (EnteroBase) and single nucleotide polymorphism (SNP) analysis. A unique cgMLST profile (>6 allele differences) was observed in 82/100 RTs, indicating that cgMLST could distinguish most, but not all, RTs. Application of cgMLST in two outbreak settings with RT078 and RT181 (known with a low intra-RT allele difference) showed no distinction between outbreak- and non-outbreak strains, in contrast to wgMLST and SNP analysis. We conclude that cgMLST has the potential to be an alternative to CE-PCR ribotyping. The method is reproducible, easy to standardize and offers higher discrimination. However, adjusted cut-off thresholds and epidemiological data are necessary to recognize outbreaks of some specific RTs. We propose to use an allelic threshold 3 alleles to identify outbreaks.


2019 ◽  
Vol 147 ◽  
Author(s):  
H. Strydom ◽  
J. Wang ◽  
S. Paine ◽  
K. Dyet ◽  
K. Cullen ◽  
...  

AbstractIncidence of human yersiniosis in New Zealand has increased between 2013 and 2017. For surveillance and outbreak investigations it is essential that an appropriate level of discrimination between pathogenicYersinia enterocoliticaisolates is provided, in order to support epidemiological linking of connected cases. Subtyping of 227Y. enterocoliticaisolates was performed using a range of different typing methods, including biotyping, serotyping and seven loci multiple-locus variable-number tandem-repeat analysis (MLVA). In addition, core genome single-nucleotide polymorphism (core SNP) analysis and multi-locus sequence typing were performed on a subset of 69 isolates. Sixty-seven different MLVA types were identified. One MLVA profile was associated with an outbreak in the Bay of Plenty region, supported by epidemiological data. Core SNP analysis showed that all the outbreak-related isolates clustered together. The subtyping and epidemiological evidence suggests that the outbreak of yersiniosis in the Bay of Plenty region between October and December 2016 could be attributed to a point source. However, subtyping results further suggest that the same clone was isolated from several regions between August 2016 and March 2017. Core SNP analysis and MLVA typing failed to differentiate betweenY. enterocoliticabiotype 2 and biotype 3. For this reason, we propose that these biotypes should be reported as a single type namely:Y. enterocoliticabiotype 2/3 and that the serotype should be prioritised as an indicator of prevalence.


2014 ◽  
Vol 80 (7) ◽  
pp. 2125-2132 ◽  
Author(s):  
Narjol Gonzalez-Escalona ◽  
Ruth Timme ◽  
Brian H. Raphael ◽  
Donald Zink ◽  
Shashi K. Sharma

ABSTRACTClostridium botulinumis a genetically diverse Gram-positive bacterium producing extremely potent neurotoxins (botulinum neurotoxins A through G [BoNT/A-G]). The complete genome sequences of three strains harboring only the BoNT/A1 nucleotide sequence are publicly available. Although these strains contain a toxin cluster (HA+OrfX−) associated with hemagglutinin genes, little is known about the genomes of subtype A1 strains (termed HA−OrfX+) that lack hemagglutinin genes in the toxin gene cluster. We sequenced the genomes of three BoNT/A1-producingC. botulinumstrains: two strains with the HA+OrfX−cluster (69A and 32A) and one strain with the HA−OrfX+cluster (CDC297). Whole-genome phylogenic single-nucleotide-polymorphism (SNP) analysis of these strains along with other publicly availableC. botulinumgroup I strains revealed five distinct lineages. Strains 69A and 32A clustered with theC. botulinumtype A1 Hall group, and strain CDC297 clustered with theC. botulinumtype Ba4 strain 657. This study reports the use of whole-genome SNP sequence analysis for discrimination ofC. botulinumgroup I strains and demonstrates the utility of this analysis in quickly differentiatingC. botulinumstrains harboring identical toxin gene subtypes. This analysis further supports previous work showing that strains CDC297 and 657 likely evolved from a common ancestor and independently acquired separate BoNT/A1 toxin gene clusters at distinct genomic locations.


2005 ◽  
Vol 134 (2) ◽  
pp. 377-383 ◽  
Author(s):  
K. H. DYET ◽  
D. R. MARTIN

An epidemic of meningococcal disease caused by serogroup B meningococci expressing the P1.7-2,4 PorA protein began in New Zealand in 1991. The PorA type has remained stable. Different porB have been found in association with the P1.7-2,4 PorA, although type 4 has been most common. The clonal origins of B:P1.7-2,4 meningococci isolated from cases during 1990 to the end of 2003 were analysed. In 1990, the year immediately preceding the recognized increase in disease rates, all three subclones (ST-41, ST-42, and ST-154) of the ST-41/44 clonal complex occurred among the five isolates of B:P1.7-2,4. The two sequence types, ST-42 and ST-154, continued to cause most disease throughout New Zealand. Isolates belonging to subclone ST-41 were mostly identified early in the epidemic and in the South Island. 16S rRNA typing indicated that isolates belonging to the subclones ST-41 and ST-154 share a common ancestor, with those typing as ST-42 more distantly related with some genetically ambiguous. It is possible that ST-41 and ST-154 may have evolved one from the other but evolution to ST-42 is more difficult to explain. It is possible that one or more of the ST types could have been introduced into New Zealand prior to the first detection of clinical cases in 1990. Genetic diversity may have occurred during carriage in the community.


Foods ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2454
Author(s):  
Rebecca N. Bland ◽  
Jared D. Johnson ◽  
Joy G. Waite-Cusic ◽  
Alexandra J. Weisberg ◽  
Elizabeth R. Riutta ◽  
...  

Recent listeriosis outbreaks linked to fresh produce suggest the need to better understand and mitigate L. monocytogenes contamination in packing and processing environments. Using whole genome sequencing (WGS) and phenotype screening assays for sanitizer tolerance, we characterized 48 L. monocytogenes isolates previously recovered from environmental samples in five produce handling facilities. Within the studied population there were 10 sequence types (STs) and 16 cgMLST types (CTs). Pairwise single nucleotide polymorphisms (SNPs) ranged from 0 to 3047 SNPs within a CT, revealing closely and distantly related isolates indicative of both sporadic and continuous contamination events within the facility. Within Facility 1, we identified a closely related cluster (0–2 SNPs) of isolates belonging to clonal complex 37 (CC37; CT9492), with isolates recovered during sampling events 1-year apart and in various locations inside and outside the facility. The accessory genome of these CC37 isolates varied from 94 to 210 genes. Notable genetic elements and mutations amongst the isolates included the bcrABC cassette (2/48), associated with QAC tolerance; mutations in the actA gene on the Listeria pathogenicity island (LIPI) 1 (20/48); presence of LIPI-3 (21/48) and LIPI-4 (23/48). This work highlights the potential use of WGS in tracing the pathogen within a facility and understanding properties of L. monocytogenes in produce settings.


2016 ◽  
Vol 144 (9) ◽  
pp. 1991-1998 ◽  
Author(s):  
A. C. BOWEN ◽  
T. HARRIS ◽  
D. C. HOLT ◽  
P. M. GIFFARD ◽  
J. R. CARAPETIS ◽  
...  

SUMMARYImpetigo is common in remote Indigenous children of northern Australia, with the primary driver in this context beingStreptococcus pyogenes[or group AStreptococcus(GAS)]. To reduce the high burden of impetigo, the transmission dynamics of GAS must be more clearly elucidated. We performed whole genome sequencing on 31 GAS isolates collected in a single community from children in 11 households with ⩾2 GAS-infected children. We aimed to determine whether transmission was occurring principally within households or across the community. The 31 isolates were represented by nine multilocus sequence types and isolates within each sequence type differed from one another by only 0–3 single nucleotide polymorphisms. There was evidence of extensive transmission both within households and across the community. Our findings suggest that strategies to reduce the burden of impetigo in this setting will need to extend beyond individual households, and incorporate multi-faceted, community-wide approaches.


2021 ◽  
Author(s):  
Hui Jiang ◽  
Gen Pan ◽  
Touming Liu ◽  
Li Chang ◽  
Siqi Huang ◽  
...  

Abstract Flax is an important oil and fibre crop grown in Northern Europe, Canada, India, and China. The development of molecular markers has accelerated the process of flax molecular breeding and has improved yield and quality. Presently, simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers in the whole genome have been developed for flax. However, the development of flax insertion/deletion (InDel) markers has not been reported. A total of 17,110 InDel markers were identified by comparing whole-genome re-sequencing data of two accessions (87-3 and 84-3) with the flax reference genome. The length of InDels ranged from 1–277 bp, with 1–15 bp accounting for the highest rate (95.55%). The most common InDels were in the form of single nucleotide (8840), dinucleotide (3700), and trinucleotide (1349), and chromosome 2 (1505) showed the highest number of InDels among flax chromosomes, while chromosome 10 (913) presented with the lowest number. From 17,110 InDel markers, 90 primers that were evenly distributed in the flax genome were selected. Thirty-two pairs of polymorphic primers were detected in two flax accessions, and the polymorphism rate was 40.70%. Furthermore, genetic diversity analysis, population structure and principal component analyse (PCA) divided 69 flax accessions into two categories, namely oilseed flax and fibre flax using 32 pairs of polymorphic primers. Additionally, correlation analysis showed that InDel-26 and InDel-81 were associated with oil content traits, and two candidate genes (lus10031535 and lus10025284) tightly linked to InDel-26 or InDel-81, might be involved in flax lipid biosynthesis and lipid metabolism. This study is the first to develop InDel markers based on re-sequencing in flax and clustered the markers into two well-separated groups for oil and fibre. The results demonstrated that InDel markers developed herein could be used for flax germplasm identification, genetic diversity analysis, and molecular marker-assisted breeding.


2019 ◽  
Vol 191 (2) ◽  
pp. 285-298 ◽  
Author(s):  
Pauline Rascle ◽  
Elodie Flaven ◽  
Frédéric Bioret ◽  
Sylvie Magnanon ◽  
Erwan Glemarec ◽  
...  

Abstract Eryngium viviparum (Apiaceae) is an endangered endemic plant of the Atlantic region of Europe, growing in seasonally flooded sites, and is characterized by a highly disjunct distribution. It occurs in just a few sites in the north-western part of the Iberian Peninsula and in a single locality in France. To improve the conservation status of E. viviparum in France, a conservation programme has been implemented to reintroduce the species. Before considering such an operation, genetic studies were conducted to determine the genetic status of the last French population and to identify the genetic source that should be considered for the best reintroduction strategy. Using microsatellite markers, we documented the genetic structure of the last French population and compared its genetic diversity with that of ten Iberian populations, which cover the three geographical regions where the species occurs. As expected, the French population of E. viviparum shows low genetic diversity due to a bottleneck and geographical isolation. The evolutionary potential appears low, with no private alleles in this population. Furthermore, this population is highly differentiated from the Iberian populations in terms of genetic variation and ecological niche. These results bring new questions regarding the conservation of E. viviparum in France, especially for management and reintroduction aimed at favouring genetic diversity and avoiding extinction.


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