scholarly journals Characterization of Streptococcus pneumoniae strains causing invasive infections using whole-genome sequencing

2020 ◽  
Vol 97 (2) ◽  
pp. 113-118 ◽  
Author(s):  
Konstantin O. Mironov ◽  
Vitaly I. Korchagin ◽  
Yuliya V. Mikhailova ◽  
Yurii G. Yanushevich ◽  
Andrey A. Shelenkov ◽  
...  

Purpose: antigenic and genetic characterization of Streptococcus pneumoniae strains isolated from patients with invasive forms of pneumococcal infection using whole-genome sequencing.Materials and Methods. The study was performed on 46 S. pneumoniae strains isolated during the PEHASus multicenter studies in 2015-2018. Sequencing was performed using Illumina protocols and equipment. The SPAdes, SeroBA, PneumoCaT software were used for data processing, as well as BIGSdb software (PubMLST.org).Results and Discussion. Whole-genome sequences of strains were obtained; the information was entered into the PubMLST database (id: 51080-51125). Ten (21%) strains were found to have serotype 3. Five (11%) strains belonged to serotype 19F and five to serogroup 6; two of them belonged to serotype 6A; one strain had 6B and 1 had 6BE serotype; 1 strain showed discordant result (6A or 6BE). Serotype 15B was identified in 3 (6.5%) strains. Serotypes 7F, 8, 9V, 14, 22F, 23F and 28A were identified in two strains each; serotypes 1, 4, 9N, 10C, 12F, 18C, 35F, 37 and 38 were found once. The proportion of strains with serotypes included in PCV13 and PPV23 vaccines was 65% and 80%, respectively. 36 sequence types were found in strains; out of them, 6 sequence types were found for the first time. A dominant sequence type or clone complexes could not be identified using multilocus sequence typing except for serotype 3 strains. The inability to identify clonal complexes is in congruence with the previously obtained data on the absence of S. pneumoniae clones associated with pneumococcal meningitis in Russia.Conclusion. The information about serotypes of S. pneumoniae causing invasive infections together with epidemiologic data about strain sources and vaccination allows us to evaluate the effectiveness of pneumococcal vaccines and provide information for improving the PCR-based routine serotyping.

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
S. Garcia-Garcia ◽  
A. Perez-Arguello ◽  
D. Henares ◽  
N. Timoneda ◽  
C. Muñoz-Almagro

Abstract Background Whole genome sequencing has emerged as a useful tool for identification and molecular characterization of pathogens. MinION (Oxford Nanopore) is a real-time third generation sequencer whose portability, affordability and speed in data production make of it an attractive device for whole genome sequencing. The objective of this study is to evaluate MinION sequencer for pathogen identification and molecular characterization of Streptococcus pneumoniae isolated at a children’s Hospital. Whole genome sequencing of 32 Streptococcus pneumoniae invasive isolates, previously characterized by standard methods (Quellung reaction, Multiplex PCR and Sanger-MLST), were performed. DNA was extracted using ZymoBIOMICS DNA Microprep kit. Quantification and purity of DNA was assessed by Qubit and Nanodrop, respectively. Library preparation was performed using the Rapid Barcoding Kit. Real-time workflow EPI2ME platform “What’s it in my pot” was used for species identification. Fast5 sequences were converted into FASTQ by Albacore software. Reads were assembled using CANU software. PathogenWatch, genomic epidemiology and pubmlst online tools were used for capsular typing and/or whole genome-MLST profile. Results Rapid identification of Streptococcus pneumoniae was achieved by “What’s in my pot”. Capsular typing was correctly assigned with PathogenWatch in all 32 isolates at serogroup level and 24 at serotype level. Whole genome-MLST results obtained by genomic epidemiology and pubmlst were consistent with double locus variant clonal complex obtained by Sanger-MLST in 31 isolates. Conclusion MinION sequencer provides a rapid, cost-effective and promising pathway for performing WGS by a pocked-sized device for epidemiological purposes but improving its sequencing accuracy will make it more appealing to be used in clinical microbiology laboratories.


2020 ◽  
Vol 21 (24) ◽  
pp. 9419
Author(s):  
Kinga Wieczorek ◽  
Arkadiusz Bomba ◽  
Jacek Osek

Listeria monocytogenes, an important foodborne pathogen, may be present in different kinds of food and in food processing environments where it can persist for a long time. In this study, 28 L. monocytogenes isolates from fish and fish manufactures were characterized by whole genome sequencing (WGS). Core genome multilocus sequence typing (cgMLST) analysis was applied to compare the present isolates with publicly available genomes of L. monocytogenes strains recovered worldwide from food and from humans with listeriosis. All but one (96.4%) of the examined isolates belonged to molecular serogroup IIa, and one isolate (3.6%) was classified to serogroup IVb. The isolates of group IIa were mainly of MLST sequence types ST121 (13 strains) and ST8 (four strains) whereas the isolate of serogroup IVb was classified to ST1. Strains of serogroup IIa were further subtyped into eight different sublineages with the most numerous being SL121 (13; 48.1% strains) which belonged to six cgMLST types. The majority of strains, irrespective of the genotypic subtype, had the same antimicrobial resistance profile. The cluster analysis identified several molecular clones typical for L. monocytogenes isolated from similar sources in other countries; however, novel molecular cgMLST types not present in the Listeria database were also identified.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Weili Cai ◽  
Schyler Nunziata ◽  
John Rascoe ◽  
Michael J. Stulberg

AbstractHuanglongbing (HLB) is a worldwide deadly citrus disease caused by the phloem-limited bacteria ‘Candidatus Liberibacter asiaticus’ (CLas) vectored by Asian citrus psyllids. In order to effectively manage this disease, it is crucial to understand the relationship among the bacterial isolates from different geographical locations. Whole genome sequencing approaches will provide more precise molecular characterization of the diversity among populations. Due to the lack of in vitro culture, obtaining the whole genome sequence of CLas is still a challenge, especially for medium to low titer samples. Hundreds of millions of sequencing reads are needed to get good coverage of CLas from an HLB positive citrus sample. In order to overcome this limitation, we present here a new method, Agilent SureSelect XT HS target enrichment, which can specifically enrich CLas from a metagenomic sample while greatly reducing cost and increasing whole genome coverage of the pathogen. In this study, the CLas genome was successfully sequenced with 99.3% genome coverage and over 72X sequencing coverage from low titer tissue samples (equivalent to 28.52 Cq using Li 16 S qPCR). More importantly, this method also effectively captures regions of diversity in the CLas genome, which provides precise molecular characterization of different strains.


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.


2014 ◽  
Vol 53 (1) ◽  
pp. 323-326 ◽  
Author(s):  
Birgit De Smet ◽  
Derek S. Sarovich ◽  
Erin P. Price ◽  
Mark Mayo ◽  
Vanessa Theobald ◽  
...  

Burkholderia pseudomalleiisolates with shared multilocus sequence types (STs) have not been isolated from different continents. We identified two STs shared between Australia and Cambodia. Whole-genome analysis revealed substantial diversity within STs, correctly identified the Asian or Australian origin, and confirmed that these shared STs were due to homoplasy.


2019 ◽  
Vol 14 (15) ◽  
pp. 1281-1292 ◽  
Author(s):  
Giovanni Lorenzin ◽  
Erika Scaltriti ◽  
Franco Gargiulo ◽  
Francesca Caccuri ◽  
Giorgio Piccinelli ◽  
...  

Aim: This study aims to characterize clinical strains of Acinetobacter baumannii with an extensively drug-resistant phenotype. Methods: VITEK® 2, Etest® method and broth microdilution method for colistin were used. PCR analysis and multilocus sequence typing Pasteur scheme were performed to identify bla-OXA genes and genetic relatedness, respectively. Whole-genome sequencing analysis was used to characterize three isolates. Results: All the isolates were susceptible only to polymyxins. blaOXA-23-like gene was the only acquired carbapenemase gene in 88.2% of the isolates. Multilocus sequence typing identified various sequence types: ST2, ST19, ST195, ST577 and ST632. Two new sequence types, namely, ST1279 and ST1280, were detected by whole-genome sequencing. Conclusion: This study showed that carbapenem-resistant A. baumannii isolates causing infections in intensive care units almost exclusively produce OXA-23, underlining their frequent spread in Italy.


Genome ◽  
2020 ◽  
Vol 63 (8) ◽  
pp. 397-405
Author(s):  
Xiaowen Yang ◽  
Ning Wang ◽  
Xiaofang Cao ◽  
Pengfei Bie ◽  
Zhifeng Xing ◽  
...  

Brucella spp., facultative intracellular pathogens that can persistently colonize animal host cells and cause zoonosis, affect public health and safety. A Brucella strain was isolated from yak in Qinghai Province. To detect whether this isolate could cause an outbreak of brucellosis and to reveal its genetic characteristics, several typing and whole-genome sequencing methods were applied to identify its species and genetic characteristics. Phylogenetic analysis based on MLVA and whole-genome sequencing revealed the genetic characteristics of the isolated strain. The results showed that the isolated strain is a B. suis biovar 1 smooth strain, and this isolate was named B. suis QH05. The results of comparative genomics and MLVA showed that B. suis QH05 is not a vaccine strain. Comparison with other B. suis strains isolated from humans and animals indicated that B. suis QH05 may be linked to specific animal and human sources. In conclusion, B. suis QH05 does not belong to the Brucella epidemic species in China, and as the first isolation of B. suis from yak, this strain expands the host range of B. suis.


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