scholarly journals Evolutionary and Genomic Insights intoClostridioides difficileSequence Type 11: a Diverse Zoonotic and Antimicrobial-Resistant Lineage of Global One Health Importance

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Daniel R. Knight ◽  
Brian Kullin ◽  
Grace O. Androga ◽  
Frederic Barbut ◽  
Catherine Eckert ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Antimicrobial Resistance ◽  
Long Range ◽  
One Health ◽  
Core Genome ◽  
Sequence Type ◽  
Content Type ◽  
Pan Genome ◽  
Clostridioides Difficile ◽  
Animal Populations

ABSTRACTClostridioides difficile(Clostridium difficile) sequence type 11 (ST11) is well established in production animal populations worldwide and contributes considerably to the global burden ofC. difficileinfection (CDI) in humans. Increasing evidence of shared ancestry and genetic overlap of PCR ribotype 078 (RT078), the most common ST11 sublineage, between human and animal populations suggests that CDI may be a zoonosis. We performed whole-genome sequencing (WGS) on a collection of 207 ST11 and closely related ST258 isolates of human and veterinary/environmental origin, comprising 16 RTs collected from Australia, Asia, Europe, and North America. Core genome single nucleotide variant (SNV) analysis identified multiple intraspecies and interspecies clonal groups (isolates separated by ≤2 core genome SNVs) in all the major RT sublineages: 078, 126, 127, 033, and 288. Clonal groups comprised isolates spread across different states, countries, and continents, indicative of reciprocal long-range dissemination and possible zoonotic/anthroponotic transmission. Antimicrobial resistance genotypes and phenotypes varied across host species, geographic regions, and RTs and included macrolide/lincosamide resistance (Tn6194[ermB]), tetracycline resistance (Tn6190[tetM] and Tn6164[tet44]), and fluoroquinolone resistance (gyrA/Bmutations), as well as numerous aminoglycoside resistance cassettes. The population was defined by a large “open” pan-genome (10,378 genes), a remarkably small core genome of 2,058 genes (only 19.8% of the gene pool), and an accessory genome containing a large and diverse collection of important prophages of theSiphoviridaeandMyoviridae. This study provides novel insights into strain relatedness and genetic variability ofC. difficileST11, a lineage of global One Health importance.IMPORTANCEHistorically,Clostridioides difficile(Clostridium difficile) has been associated with life-threatening diarrhea in hospitalized patients. Increasing rates ofC. difficileinfection (CDI) in the community suggest exposure toC. difficilereservoirs outside the hospital, including animals, the environment, or food.C. difficilesequence type 11 (ST11) is known to infect/colonize livestock worldwide and comprises multiple ribotypes, many of which cause disease in humans, suggesting CDI may be a zoonosis. Using high-resolution genomics, we investigated the evolution and zoonotic potential of ST11 and a new closely related ST258 lineage sourced from diverse origins. We found multiple intra- and interspecies clonal transmission events in all ribotype sublineages. Clones were spread across multiple continents, often without any health care association, indicative of zoonotic/anthroponotic long-range dissemination in the community. ST11 possesses a massive pan-genome and numerous clinically important antimicrobial resistance elements and prophages, which likely contribute to the success of this globally disseminated lineage of One Health importance.

scholarly journals One Health Genomic Surveillance ofEscherichia coliDemonstrates Distinct Lineages and Mobile Genetic Elements in Isolates from Humans versus Livestock

mBio ◽  
2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Catherine Ludden ◽  
Kathy E. Raven ◽  
Dorota Jamrozy ◽  
Theodore Gouliouris ◽  
Beth Blane ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Resistance Genes ◽  
One Health ◽  
Core Genome ◽  
Bloodstream Infections ◽  
Mobile Genetic Elements ◽  
Human Infection ◽  
Content Type ◽  
E Coli ◽  
Antimicrobial Resistance Genes

ABSTRACTLivestock have been proposed as a reservoir for drug-resistantEscherichia colithat infect humans. We isolated and sequenced 431E. coliisolates (including 155 extended-spectrum β-lactamase [ESBL]-producing isolates) from cross-sectional surveys of livestock farms and retail meat in the East of England. These were compared with the genomes of 1,517E. colibacteria associated with bloodstream infection in the United Kingdom. Phylogenetic core genome comparisons demonstrated that livestock and patient isolates were genetically distinct, suggesting thatE. colicausing serious human infection had not directly originated from livestock. In contrast, we observed highly related isolates from the same animal species on different farms. Screening all 1,948 isolates for accessory genes encoding antibiotic resistance revealed 41 different genes present in variable proportions in human and livestock isolates. Overall, we identified a low prevalence of shared antimicrobial resistance genes between livestock and humans based on analysis of mobile genetic elements and long-read sequencing. We conclude that within the confines of our sampling framework, there was limited evidence that antimicrobial-resistant pathogens associated with serious human infection had originated from livestock in our region.IMPORTANCEThe increasing prevalence ofE. colibloodstream infections is a serious public health problem. We used genomic epidemiology in a One Health study conducted in the East of England to examine putative sources ofE. coliassociated with serious human disease.E. colifrom 1,517 patients with bloodstream infections were compared with 431 isolates from livestock farms and meat. Livestock-associated and bloodstream isolates were genetically distinct populations based on core genome and accessory genome analyses. Identical antimicrobial resistance genes were found in livestock and human isolates, but there was limited overlap in the mobile elements carrying these genes. Within the limitations of sampling, our findings do not support the idea thatE. colicausing invasive disease or their resistance genes are commonly acquired from livestock in our region.

scholarly journals Population Structure and Antimicrobial Resistance of Canine UropathogenicEscherichia coli

2018 ◽  
Vol 56 (9) ◽  
Author(s):  
Tessa E. LeCuyer ◽  
Barbara A. Byrne ◽  
Joshua B. Daniels ◽  
Dubraska V. Diaz-Campos ◽  
G. Kenitra Hammac ◽  
...  
Keyword(s):  
Population Structure ◽  
Antimicrobial Resistance ◽  
Companion Animals ◽  
Sequence Type ◽  
Content Type ◽  
E Coli ◽  
Extraintestinal Disease ◽  
Human Infections ◽  
Sequence Types

ABSTRACTEscherichia coliis the most common cause of human and canine urinary tract infection (UTI). Clonal groups, often with high levels of antimicrobial resistance, are a major component of theE. colipopulation that causes human UTI. While little is known about the population structure ofE. colithat causes UTI in dogs, there is evidence that dogs and humans can share fecal strains ofE. coliand that human-associated strains can cause disease in dogs. In order to better characterize theE. colistrains that cause canine UTI, we analyzed 295E. coliisolates obtained from canine urine samples from five veterinary diagnostic laboratories and analyzed their multilocus sequence types, phenotypic and genotypic antimicrobial resistance profiles, and virulence-associated gene repertoires. Sequence type 372 (ST372), an infrequent human pathogen, was the predominant sequence type in dogs at all locations. Extended-spectrum β-lactamase-producing isolates withblaCTX-Mgenes were uncommon in canine isolates but when present were often associated with sequence types that have been described in human infections. This provides support for occasional cross-host-species sharing of strains that cause extraintestinal disease and highlights the importance of understanding the role of companion animals in the overall transmission patterns of extraintestinal pathogenicE. coli.

scholarly journals Comparison of Molecular Subtyping and Antimicrobial Resistance Detection Methods Used in a Large Multistate Outbreak of Extensively Drug-Resistant Campylobacter jejuni Infections Linked to Pet Store Puppies

2020 ◽  
Vol 58 (10) ◽  
Author(s):  
Lavin A. Joseph ◽  
Louise K. Francois Watkins ◽  
Jessica Chen ◽  
Kaitlin A. Tagg ◽  
Christy Bennett ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Campylobacter Jejuni ◽  
Multilocus Sequence Typing ◽  
The United States ◽  
Sequence Type ◽  
Outbreak Detection ◽  
Detection Methods ◽  
Drug Resistant ◽  
Molecular Subtyping ◽  
Content Type

ABSTRACT Campylobacter jejuni is a leading cause of enteric bacterial illness in the United States. Traditional molecular subtyping methods, such as pulsed-field gel electrophoresis (PFGE) and 7-gene multilocus sequence typing (MLST), provided limited resolution to adequately identify C. jejuni outbreaks and separate out sporadic isolates during outbreak investigations. Whole-genome sequencing (WGS) has emerged as a powerful tool for C. jejuni outbreak detection. In this investigation, 45 human and 11 puppy isolates obtained during a 2016–2018 outbreak linked to pet store puppies were sequenced. Core genome multilocus sequence typing (cgMLST) and high-quality single nucleotide polymorphism (hqSNP) analysis of the sequence data separated the isolates into the same two clades containing minor within-clade differences; however, cgMLST analysis does not require selection of an appropriate reference genome, making the method preferable to hqSNP analysis for Campylobacter surveillance and cluster detection. The isolates were classified as sequence type 2109 (ST2109)—a rarely seen MLST sequence type. PFGE was performed on 38 human and 10 puppy isolates; PFGE patterns did not reliably predict clustering by cgMLST analysis. Genetic detection of antimicrobial resistance determinants predicted that all outbreak-associated isolates would be resistant to six drug classes. Traditional antimicrobial susceptibility testing (AST) confirmed a high correlation between genotypic and phenotypic antimicrobial resistance determinations. WGS analysis linked C. jejuni isolates in humans and pet store puppies even when canine exposure information was unknown, aiding the epidemiological investigation during the outbreak. WGS data were also used to quickly identify the highly drug-resistant profile of these outbreak-associated C. jejuni isolates.

scholarly journals Clostridium difficileLipoprotein GerS Is Required for Cortex Modification and Thus Spore Germination

mSphere ◽  
2018 ◽  
Vol 3 (3) ◽  
Author(s):  
Oscar R. Diaz ◽  
Cameron V. Sayer ◽  
David L. Popham ◽  
Aimee Shen
Keyword(s):  
Clostridium Difficile ◽  
Spore Germination ◽  
Protective Layer ◽  
Thick Layer ◽  
Lytic Enzyme ◽  
Gram Positive ◽  
Content Type ◽  
Clostridioides Difficile ◽  
Antibiotic Associated Diarrhea ◽  
Biochemical Analyses

ABSTRACTClostridium difficile, also known asClostridioides difficile, is a Gram-positive, spore-forming bacterium that is a leading cause of antibiotic-associated diarrhea.C. difficileinfections begin when its metabolically dormant spores germinate to form toxin-producing vegetative cells. Successful spore germination depends on the degradation of the cortex, a thick layer of modified peptidoglycan that maintains dormancy. Cortex degradation is mediated by the SleC cortex lytic enzyme, which is thought to recognize the cortex-specific modification muramic-δ-lactam.C. difficilecortex degradation also depends on thePeptostreptococcaceae-specific lipoprotein GerS for unknown reasons. In this study, we tested whether GerS regulates production of muramic-δ-lactam and thus controls the ability of SleC to recognize its cortex substrate. By comparing the muropeptide profiles of ΔgerSspores to those of spores lacking either CwlD or PdaA, both of which mediate cortex modification inBacillus subtilis, we determined thatC. difficileGerS, CwlD, and PdaA are all required to generate muramic-δ-lactam. Both GerS and CwlD were needed to cleave the peptide side chains from N-acetylmuramic acid, suggesting that these two factors act in concert. Consistent with this hypothesis, biochemical analyses revealed that GerS and CwlD directly interact and that CwlD modulates GerS incorporation into mature spores. Since ΔgerS, ΔcwlD, and ΔpdaAspores exhibited equivalent germination defects, our results indicate thatC. difficilespore germination depends on cortex-specific modifications, reveal GerS as a novel regulator of these processes, and highlight additional differences in the regulation of spore germination inC. difficilerelative toB. subtilisand other spore-forming organisms.IMPORTANCEThe Gram-positive, spore-forming bacteriumClostridium difficileis a leading cause of antibiotic-associated diarrhea. BecauseC. difficileis an obligate anaerobe, its aerotolerant spores are essential for transmitting disease, and their germination into toxin-producing cells is necessary for causing disease. Spore germination requires the removal of the cortex, a thick layer of modified peptidoglycan that maintains spore dormancy. Cortex degradation is mediated by the SleC hydrolase, which is thought to recognize cortex-specific modifications. Cortex degradation also requires the GerS lipoprotein for unknown reasons. In our study, we tested whether GerS is required to generate cortex-specific modifications by comparing the cortex composition of ΔgerSspores to the cortex composition of spores lacking two putative cortex-modifying enzymes, CwlD and PdaA. These analyses revealed that GerS, CwlD, and PdaA are all required to generate cortex-specific modifications. Since loss of these modifications in ΔgerS, ΔcwlD, and ΔpdaAmutants resulted in spore germination and heat resistance defects, the SleC cortex lytic enzyme depends on cortex-specific modifications to efficiently degrade this protective layer. Our results further indicate that GerS and CwlD are mutually required for removing peptide chains from spore peptidoglycan and revealed a novel interaction between these proteins. Thus, our findings provide new mechanistic insight intoC. difficilespore germination.

scholarly journals Escherichia coliSequence Type 410 Is Causing New International High-Risk Clones

mSphere ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. e00337-18 ◽  
Author(s):  
Louise Roer ◽  
Søren Overballe-Petersen ◽  
Frank Hansen ◽  
Kristian Schønning ◽  
Mikala Wang ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
High Risk ◽  
Antimicrobial Resistance ◽  
Sequence Type ◽  
Recurrent Infections ◽  
Content Type ◽  
E Coli ◽  
The Past ◽  
Carbapenemase Gene ◽  
Globally Distributed

ABSTRACTEscherichia colisequence type 410 (ST410) has been reported worldwide as an extraintestinal pathogen associated with resistance to fluoroquinolones, third-generation cephalosporins, and carbapenems. In the present study, we investigated national epidemiology of ST410E. coliisolates from Danish patients. Furthermore,E. coliST410 was investigated in a global context to provide further insight into the acquisition of the carbapenemase genesblaOXA-181andblaNDM-5of this successful lineage. From 127 whole-genome-sequenced isolates, we reconstructed an evolutionary framework ofE. coliST410 which portrays the antimicrobial-resistant clades B2/H24R, B3/H24Rx, and B4/H24RxC. The B2/H24R and B3/H24Rx clades emerged around 1987, concurrently with the C1/H30R and C2/H30Rx clades inE. coliST131. B3/H24Rx appears to have evolved by the acquisition of the extended-spectrum β-lactamase (ESBL)-encoding geneblaCTX-M-15and an IncFII plasmid, encoding IncFIA and IncFIB. Around 2003, the carbapenem-resistant clade B4/H24RxC emerged when ST410 acquired an IncX3 plasmid carrying ablaOXA-181carbapenemase gene. Around 2014, the clade B4/H24RxC acquired a second carbapenemase gene,blaNDM-5, on a conserved IncFII plasmid. From an epidemiological investigation of 49E. coliST410 isolates from Danish patients, we identified five possible regional outbreaks, of which one outbreak involved nine patients withblaOXA-181- andblaNDM-5-carrying B4/H24RxC isolates. The accumulated multidrug resistance inE. coliST410 over the past two decades, together with its proven potential of transmission between patients, poses a high risk in clinical settings, and thus,E. coliST410 should be considered a lineage with emerging “high-risk” clones, which should be monitored closely in the future.IMPORTANCEExtraintestinal pathogenicEscherichia coli(ExPEC) is the main cause of urinary tract infections and septicemia. Significant attention has been given to the ExPEC sequence type ST131, which has been categorized as a “high-risk” clone. High-risk clones are globally distributed clones associated with various antimicrobial resistance determinants, ease of transmission, persistence in hosts, and effective transmission between hosts. The high-risk clones have enhanced pathogenicity and cause severe and/or recurrent infections. We show that clones of theE. coliST410 lineage persist and/or cause recurrent infections in humans, including bloodstream infections. We found evidence of ST410 being a highly resistant globally distributed lineage, capable of patient-to-patient transmission causing hospital outbreaks. Our analysis suggests that the ST410 lineage should be classified with the potential to cause new high-risk clones. Thus, with the clonal expansion over the past decades and increased antimicrobial resistance to last-resort treatment options, ST410 needs to be monitored prospectively.

scholarly journals Carbapenem-Resistant Klebsiella pneumoniae Strains Exhibit Diversity in Aminoglycoside-Modifying Enzymes, Which Exert Differing Effects on Plazomicin and Other Agents

2014 ◽  
Vol 58 (8) ◽  
pp. 4443-4451 ◽  
Author(s):  
Reem Almaghrabi ◽  
Cornelius J. Clancy ◽  
Yohei Doi ◽  
Binghua Hao ◽  
Liang Chen ◽  
...  
Keyword(s):  
Antimicrobial Resistance ◽  
Klebsiella Pneumoniae ◽  
Bactericidal Activity ◽  
Sequence Type ◽  
Content Type ◽  
Molecular Assays ◽  
Carbapenem Resistant ◽  
Research Priority ◽  
Gentamicin Resistance

ABSTRACTWe measuredin vitroactivity of plazomicin, a next-generation aminoglycoside, and other aminoglycosides against 50 carbapenem-resistantKlebsiella pneumoniaestrains from two centers and correlated the results with the presence of various aminoglycoside-modifying enzymes (AMEs). Ninety-four percent of strains were sequence type 258 (ST258) clones, which exhibited 5ompK36genotypes; 80% and 10% of strains producedKlebsiella pneumoniaecarbapenemase 2 (KPC-2) and KPC-3, respectively. Ninety-eight percent of strains possessed AMEs, including AAC(6′)-Ib (98%), APH(3′)-Ia (56%), AAC(3)-IV (38%), and ANT(2″)-Ia (2%). Gentamicin, tobramycin, and amikacin nonsusceptibility rates were 40, 98, and 16%, respectively. Plazomicin MICs ranged from 0.25 to 1 μg/ml. Tobramycin and plazomicin MICs correlated with gentamicin MICs (r= 0.75 and 0.57, respectively). Plazomicin exerted bactericidal activity against 17% (1× MIC) and 94% (4× MIC) of strains. All strains with AAC(6′)-Ib were tobramycin-resistant; 16% were nonsusceptible to amikacin. AAC(6′)-Ib combined with another AME was associated with higher gentamicin, tobramycin, and plazomicin MICs than AAC(6′)-Ib alone (P= 0.01, 0.0008, and 0.046, respectively). The presence of AAC(3)-IV in a strain was also associated with higher gentamicin, tobramycin, and plazomicin MICs (P= 0.0006,P< 0.0001, andP= 0.01, respectively). The combination of AAC(6′)-Ib and another AME, the presence of AAC(3)-IV, and the presence of APH(3′)-Ia were each associated with gentamicin resistance (P= 0.0002, 0.003, and 0.01, respectively). In conclusion, carbapenem-resistantK. pneumoniaestrains (including ST258 clones) exhibit highly diverse antimicrobial resistance genotypes and phenotypes. Plazomicin may offer a treatment option against strains resistant to other aminoglycosides. The development of molecular assays that predict antimicrobial responses among carbapenem-resistantK. pneumoniaestrains should be a research priority.

scholarly journals A global to local genomics analysis of Clostridioides difficile ST1/RT027 identifies cryptic transmission events in a northern Arizona healthcare network

2019 ◽  
Vol 5 (7) ◽  
Author(s):  
Charles H. D. Williamson ◽  
Nathan E. Stone ◽  
Amalee E. Nunnally ◽  
Heidie M. Hornstra ◽  
David M. Wagner ◽  
...  
Keyword(s):  
Type Species ◽  
Sequence Type ◽  
Infection Prevention And Control ◽  
Polymorphism Analysis ◽  
Whole Genome ◽  
Content Type ◽  
Northern Arizona ◽  
Healthcare Network ◽  
Link Type ◽  
Clostridioides Difficile

Clostridioides difficile is a ubiquitous, diarrhoeagenic pathogen often associated with healthcare-acquired infections that can cause a range of symptoms from mild, self-limiting disease to toxic megacolon and death. Since the early 2000s, a large proportion of C. difficile cases have been attributed to the ribotype 027 (RT027) lineage, which is associated with sequence type 1 (ST1) in the C. difficile multilocus sequence typing scheme. The spread of ST1 has been attributed, in part, to resistance to fluoroquinolones used to treat unrelated infections, which creates conditions ideal for C. difficile colonization and proliferation. In this study, we analysed 27 isolates from a healthcare network in northern Arizona, USA, and 1352 publicly available ST1 genomes to place locally sampled isolates into a global context. Whole genome, single nucleotide polymorphism analysis demonstrated that at least six separate introductions of ST1 were observed in healthcare facilities in northern Arizona over an 18-month sampling period. A reconstruction of transmission networks identified potential nosocomial transmission of isolates, which were only identified via whole genome sequence analysis. Antibiotic resistance heterogeneity was observed among ST1 genomes, including variability in resistance profiles among locally sampled ST1 isolates. To investigate why ST1 genomes are so common globally and in northern Arizona, we compared all high-quality C. difficile genomes and identified that ST1 genomes have gained and lost a number of genomic regions compared to all other C. difficile genomes; analyses of other toxigenic C. difficile sequence types demonstrate that this loss may be anomalous and could be related to niche specialization. These results suggest that a combination of antimicrobial resistance and gain and loss of specific genes may explain the prominent association of this sequence type with C. difficile infection cases worldwide. The degree of genetic variability in ST1 suggests that classifying all ST1 genomes into a quinolone-resistant hypervirulent clone category may not be appropriate. Whole genome sequencing of clinical C. difficile isolates provides a high-resolution surveillance strategy for monitoring persistence and transmission of C. difficile and for assessing the performance of infection prevention and control strategies.

scholarly journals ANTIMICROBIAL RESISTANCE PROGRAMS IN THE EUROPEAN UNION

2018 ◽  
Vol 6 ◽  
pp. 978-985
Author(s):  
Ana Maria Zorlescu ◽  
Stelian Baraitareanu ◽  
Doina Danes
Keyword(s):  
European Union ◽  
Antimicrobial Resistance ◽  
One Health ◽  
Action Plan ◽  
Animal Health ◽  
Good Practice ◽  
The European Union ◽  
Member States ◽  
Animal Populations ◽  
The One

INTRODUCTION: Antimicrobial resistance is one of the topical issues that is part of the “One Health” concept with implications for animal health, human health, and even environmental “health”. At the European Commission (EC) level, legislation has been issued for the monitoring of antimicrobial resistance and these rules are applicable by each Member State (MS). For the proper implementation of the above legislation, audits are carried out in Member States that have developed programs on antimicrobial resistance that go beyond the EC's requests.OBJECTIVES: The aim of the study was the analysis of existing data reports, legislation and recommendations on antimicrobial resistance through which surveillance and monitoring is carried out in the European Union (EU).  METHODS: The audit reports issued between 2015 and 2017 by the Food Veterinary Office (FVO), as well as the articles and studies issued by the EC through the antimicrobial resistance institutes were analysed.RESULTS: The FVO conducted audits to “evaluate the monitoring and reporting of antimicrobial resistance in zoonotic and commensal bacteria in certain food-producing animal populations and food” in 12 MS, and audits to “gather information on the prudent use of antimicrobials in animals” in 8 MS. These are countries that have very well implemented the EC's requests and included the “One Health” perspective in antimicrobial resistance programs. Some Member States have risk management strategies for reducing antimicrobial resistance for more than 20 years. They have carried out research projects on antimicrobial resistance. There is an action plan on antimicrobial resistance at the EC level, but their implementation and understanding up to the level of all actors involved in this issue varies from MS to MS. Antimicrobial resistance in the animal population is a topical issue, notoriety among the actors involved, as well as an interdisciplinary problem with indirect results. The same principle of antimicrobial resistance in animals is applicable to humans and the environment as such, this problem can be embedded in the concept of “One Health”. The overall objective of the MS is to generate knowledge and tools to “combat” antimicrobial resistance in animals, humans and even the environment.CONCLUSION: As a conclusion, in order to improve and optimize antimicrobial resistance programs, a “good practice guide” can be achieved by MS with extensive experience in this area, to be used by MS with a more precarious application and over time to harmonize antimicrobial resistance programs within the EU.

scholarly journals Rapid Increase of CTX-M-Producing Shigella sonnei Isolates in Switzerland Due to Spread of Common Plasmids and International Clones

2020 ◽  
Vol 64 (10) ◽  
Author(s):  
Edgar I. Campos-Madueno ◽  
Odette J. Bernasconi ◽  
Aline I. Moser ◽  
Peter M. Keller ◽  
Francesco Luzzaro ◽  
...  
Keyword(s):  
Core Genome ◽  
The United States ◽  
Sequence Type ◽  
Shigella Sonnei ◽  
Single Nucleotide Variants ◽  
Single Nucleotide ◽  
Content Type ◽  
Phylogenetic Comparison ◽  
The United Kingdom ◽  
Extended Spectrum

ABSTRACT The Swiss Centre for Antibiotic Resistance (ANRESIS) has recently noted an increase of extended-spectrum cephalosporin-resistant (ESC-R) Shigella sonnei isolates nationwide (3.8% in 2016 versus 37.5% in 2019). To understand this phenomenon, we analyzed 25 representative isolates (of which 14 were ESC-R) collected in Switzerland during 2016 to 2019. Whole-genome sequencing was achieved using both the Illumina and the Nanopore platforms. Both ESC-R and extended-spectrum cephalosporin-susceptible isolates belonged to sequence type 152 (ST152). The ESC-R isolates carried blaCTX-M-3 in IncI1-pST57 (n = 5), blaCTX-M-15 in IncFII (F2:A-:B-) (n = 5), blaCTX-M-15 in IncI1-pST16, and blaCTX-M-27, blaCTX-M-55, or blaCTX-M-134 in other IncFII plasmids (n = 1 each). Plasmids having the same bla and Inc group exhibited high degrees of genetic identity to each other but also to plasmids previously reported in other Enterobacterales. Core-genome analysis showed that there were 4 main clusters, each of which included strains that differed by <58 single nucleotide variants (SNVs) and that consisted of both blaCTX-M-positive and blaCTX-M-negative isolates. Moreover, most isolates belonging to the same cluster shared an identical core-genome sequence type (cgST). For instance, cluster 1 included 4 isolates of cgST113036, of which only 3 harbored the IncI1-pST57 blaCTX-M-3-positive plasmid. The 25 S. sonnei isolates were also subjected to phylogenetic comparison with deposited international strains. As a result, matching isolates (isolates that had the same cgST and that differed by <8 SNVs) have been reported in the United Kingdom, the United States, France, and the Netherlands. Overall, our results suggest that some common S. sonnei clusters can spread between continents and can be imported into other nations after international trips. Such clusters include, in part, isolates that do not possess blaESBL-harboring plasmids, indicating their tendency to acquire them from other Enterobacterales.

scholarly journals Hash-Based Core Genome Multilocus Sequence Typing for Clostridium difficile

2019 ◽  
Vol 58 (1) ◽  
Author(s):  
David W. Eyre ◽  
Tim E. A. Peto ◽  
Derrick W. Crook ◽  
A. Sarah Walker ◽  
Mark H. Wilcox
Keyword(s):  
Clostridium Difficile ◽  
Multilocus Sequence Typing ◽  
Core Genome ◽  
Genetic Relationships ◽  
Nucleotide Polymorphisms ◽  
Content Type ◽  
Recent Transmission ◽  
A Genome ◽  
Performance Penalty

ABSTRACT Pathogen whole-genome sequencing has huge potential as a tool to better understand infection transmission. However, rapidly identifying closely related genomes among a background of thousands of other genomes is challenging. Here, we describe a refinement to core genome multilocus sequence typing (cgMLST) in which alleles at each gene are reproducibly converted to a unique hash, or short string of letters (hash-cgMLST). This avoids the resource-intensive need for a single centralized database of sequentially numbered alleles. We test the reproducibility and discriminatory power of cgMLST/hash-cgMLST compared to those of mapping-based approaches in Clostridium difficile, using repeated sequencing of the same isolates (replicates) and data from consecutive infection isolates from six English hospitals. Hash-cgMLST provided the same results as standard cgMLST, with minimal performance penalty. Comparing 272 replicate sequence pairs using reference-based mapping, there were 0, 1, or 2 single-nucleotide polymorphisms (SNPs) between 262 (96%), 5 (2%), and 1 (<1%) of the pairs, respectively. Using hash-cgMLST, 218 (80%) of replicate pairs assembled with SPAdes had zero gene differences, and 31 (11%), 5 (2%), and 18 (7%) pairs had 1, 2, and >2 differences, respectively. False gene differences were clustered in specific genes and associated with fragmented assemblies, but were reduced using the SKESA assembler. Considering 412 pairs of infections with ≤2 SNPS, i.e., consistent with recent transmission, 376 (91%) had ≤2 gene differences and 16 (4%) had ≥4. Comparing a genome to 100,000 others took <1 min using hash-cgMLST. Hash-cgMLST is an effective surveillance tool for rapidly identifying clusters of related genomes. However, cgMLST/hash-cgMLST generate more false variants than mapping-based approaches. Follow-up mapping-based analyses are likely required to precisely define close genetic relationships.

Sign in / Sign up

Export Citation Format

Share Document