Whole-Genome Sequencing for Detecting Antimicrobial Resistance in Nontyphoidal Salmonella

ABSTRACTLaboratory-basedin vitroantimicrobial susceptibility testing is the foundation for guiding anti-infective therapy and monitoring antimicrobial resistance trends. We used whole-genome sequencing (WGS) technology to identify known antimicrobial resistance determinants among strains of nontyphoidalSalmonellaand correlated these with susceptibility phenotypes to evaluate the utility of WGS for antimicrobial resistance surveillance. Six hundred fortySalmonellaof 43 different serotypes were selected from among retail meat and human clinical isolates that were tested for susceptibility to 14 antimicrobials using broth microdilution. The MIC for each drug was used to categorize isolates as susceptible or resistant based on Clinical and Laboratory Standards Institute clinical breakpoints or National Antimicrobial Resistance Monitoring System (NARMS) consensus interpretive criteria. Each isolate was subjected to whole-genome shotgun sequencing, and resistance genes were identified from assembled sequences. A total of 65 unique resistance genes, plus mutations in two structural resistance loci, were identified. There were more unique resistance genes (n =59) in the 104 human isolates than in the 536 retail meat isolates (n =36). Overall, resistance genotypes and phenotypes correlated in 99.0% of cases. Correlations approached 100% for most classes of antibiotics but were lower for aminoglycosides and beta-lactams. We report the first finding of extended-spectrum β-lactamases (ESBLs) (blaCTX-M1andblaSHV2a) in retail meat isolates ofSalmonellain the United States. Whole-genome sequencing is an effective tool for predicting antibiotic resistance in nontyphoidalSalmonella, although the use of more appropriate surveillance breakpoints and increased knowledge of new resistance alleles will further improve correlations.

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Whole-Genome Sequencing Analysis Accurately Predicts Antimicrobial Resistance Phenotypes in Campylobacter spp.

Applied and Environmental Microbiology ◽

10.1128/aem.02873-15 ◽

2015 ◽

Vol 82 (2) ◽

pp. 459-466 ◽

Cited By ~ 132

Author(s):

S. Zhao ◽

G. H. Tyson ◽

Y. Chen ◽

C. Li ◽

S. Mukherjee ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Resistance Genes ◽

Antimicrobial Agents ◽

The United States ◽

23S Rrna ◽

Whole Genome ◽

Sequencing Analysis ◽

Content Type

ABSTRACTThe objectives of this study were to identify antimicrobial resistance genotypes forCampylobacterand to evaluate the correlation between resistance phenotypes and genotypes usingin vitroantimicrobial susceptibility testing and whole-genome sequencing (WGS). A total of 114Campylobacterspecies isolates (82C. coliand 32C. jejuni) obtained from 2000 to 2013 from humans, retail meats, and cecal samples from food production animals in the United States as part of the National Antimicrobial Resistance Monitoring System were selected for study. Resistance phenotypes were determined using broth microdilution of nine antimicrobials. Genomic DNA was sequenced using the Illumina MiSeq platform, and resistance genotypes were identified using assembled WGS sequences through blastx analysis. Eighteen resistance genes, includingtet(O),blaOXA-61,catA,lnu(C),aph(2″)-Ib,aph(2″)-Ic,aph(2′)-If,aph(2″)-Ig,aph(2″)-Ih,aac(6′)-Ie-aph(2″)-Ia,aac(6′)-Ie-aph(2″)-If,aac(6′)-Im,aadE,sat4,ant(6′),aad9,aph(3′)-Ic, andaph(3′)-IIIa, and mutations in two housekeeping genes (gyrAand 23S rRNA) were identified. There was a high degree of correlation between phenotypic resistance to a given drug and the presence of one or more corresponding resistance genes. Phenotypic and genotypic correlation was 100% for tetracycline, ciprofloxacin/nalidixic acid, and erythromycin, and correlations ranged from 95.4% to 98.7% for gentamicin, azithromycin, clindamycin, and telithromycin. All isolates were susceptible to florfenicol, and no genes associated with florfenicol resistance were detected. There was a strong correlation (99.2%) between resistance genotypes and phenotypes, suggesting that WGS is a reliable indicator of resistance to the nine antimicrobial agents assayed in this study. WGS has the potential to be a powerful tool for antimicrobial resistance surveillance programs.

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Comparative Whole-Genome Phylogeny of Animal, Environmental, and Human Strains Confirms the Genogroup Organization and Diversity of the Stenotrophomonas maltophilia Complex

Applied and Environmental Microbiology ◽

10.1128/aem.02919-19 ◽

2020 ◽

Vol 86 (10) ◽

Author(s):

Mélanie Mercier-Darty ◽

Guilhem Royer ◽

Brigitte Lamy ◽

Chadly Charron ◽

Olivier Lemenand ◽

...

Keyword(s):

Genetic Diversity ◽

Antimicrobial Resistance ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Resistance Genes ◽

Stenotrophomonas Maltophilia ◽

Whole Genome ◽

Content Type ◽

Genetic Organization ◽

Animal Strains

ABSTRACT The Stenotrophomonas maltophilia complex (Smc) comprises opportunistic environmental Gram-negative bacilli responsible for a variety of infections in both humans and animals. Beyond its large genetic diversity, its genetic organization in genogroups was recently confirmed through the whole-genome sequencing of human and environmental strains. As they are poorly represented in these analyses, we sequenced the whole genomes of 93 animal strains to determine their genetic background and characteristics. Combining these data with 81 newly sequenced human strains and the genomes available from RefSeq, we performed a genomic analysis that included 375 nonduplicated genomes with various origins (animal, 104; human, 226; environment, 30; unknown, 15). Phylogenetic analysis and clustering based on genome-wide average nucleotide identity confirmed and specified the genetic organization of Smc in at least 20 genogroups. Two new genogroups were identified, and two previously described groups were further divided into two subgroups each. Comparing the strains isolated from different host types and their genogroup affiliation, we observed a clear disequilibrium in certain groups. Surprisingly, some antimicrobial resistance genes, integrons, and/or clusters of attC sites lacking integron-integrase (CALIN) sequences targeting antimicrobial compounds extensively used in animals were mainly identified in animal strains. We also identified genes commonly found in animal strains coding for efflux systems. The result of a large whole-genome analysis performed by us supports the hypothesis of the putative contribution of animals as a reservoir of Stenotrophomonas maltophilia complex strains and/or resistance genes for strains in humans. IMPORTANCE Given its naturally large antimicrobial resistance profile, the Stenotrophomonas maltophilia complex (Smc) is a set of emerging pathogens of immunosuppressed and cystic fibrosis patients. As it is group of environmental microorganisms, this adaptation to humans is an opportunity to understand the genetic and metabolic selective mechanisms involved in this process. The previously reported genomic organization was incomplete, as data from animal strains were underrepresented. We added the missing piece of the puzzle with whole-genome sequencing of 93 strains of animal origin. Beyond describing the phylogenetic organization, we confirmed the genetic diversity of the Smc, which could not be estimated through routine phenotype- or matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF)-based laboratory tests. Animals strains seem to play a key role in the diversity of Smc and could act as a reservoir for mobile resistance genes. Some genogroups seem to be associated with particular hosts; the genetic support of this association and the role of the determinants/corresponding genes need to be explored.

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Conjugal Transfer, Whole-Genome Sequencing, and Plasmid Analysis of Four mcr-1-Bearing Isolates from U.S. Patients

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02417-18 ◽

2019 ◽

Vol 63 (4) ◽

Cited By ~ 1

Author(s):

Wenming Zhu ◽

Adrian Lawsin ◽

Rebecca L. Lindsey ◽

Dhwani Batra ◽

Kristen Knipe ◽

...

Keyword(s):

Escherichia Coli ◽

Antimicrobial Resistance ◽

Genome Sequencing ◽

Resistance Genes ◽

Whole Genome ◽

Colistin Resistance ◽

Content Type ◽

Plasmid Analysis ◽

Antimicrobial Resistance Genes

ABSTRACT Four Enterobacteriaceae clinical isolates bearing mcr-1 gene-harboring plasmids were characterized. All isolates demonstrated the ability to transfer colistin resistance to Escherichia coli; plasmids were stable in conjugants after multiple passages on nonselective media. mcr-1 was located on an IncX4 (n = 3) or IncN (n = 1) plasmid. The IncN plasmid harbored 13 additional antimicrobial resistance genes. Results indicate that the mcr-1-bearing plasmids in this study were highly transferable in vitro and stable in the recipients.

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Genomic Analysis of a Pan-Resistant Isolate ofKlebsiella pneumoniae, United States 2016

mBio ◽

10.1128/mbio.00440-18 ◽

2018 ◽

Vol 9 (2) ◽

Cited By ~ 16

Author(s):

Tom J. B. de Man ◽

Joseph D. Lutgring ◽

David R. Lonsway ◽

Karen F. Anderson ◽

Julia A. Kiehlbauch ◽

...

Keyword(s):

Public Health ◽

United States ◽

Antimicrobial Resistance ◽

Klebsiella Pneumoniae ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

The United States ◽

Whole Genome ◽

Beta Lactams ◽

Content Type

ABSTRACTAntimicrobial resistance is a threat to public health globally and leads to an estimated 23,000 deaths annually in the United States alone. Here, we report the genomic characterization of an unusualKlebsiella pneumoniae, nonsusceptible to all 26 antibiotics tested, that was isolated from a U.S. patient. The isolate harbored four known beta-lactamase genes, including plasmid-mediatedblaNDM-1andblaCMY-6, as well as chromosomalblaCTX-M-15andblaSHV-28, which accounted for resistance to all beta-lactams tested. In addition, sequence analysis identified mechanisms that could explain all other reported nonsusceptibility results, including nonsusceptibility to colistin, tigecycline, and chloramphenicol. Two plasmids, IncA/C2 and IncFIB, were closely related to mobile elements described previously and isolated from Gram-negative bacteria from China, Nepal, India, the United States, and Kenya, suggesting possible origins of the isolate and plasmids. This is one of the firstK. pneumoniaeisolates in the United States to have been reported to the Centers for Disease Control and Prevention (CDC) as nonsusceptible to all drugs tested, including all beta-lactams, colistin, and tigecycline.IMPORTANCEAntimicrobial resistance is a major public health threat worldwide. Bacteria that are nonsusceptible or resistant to all antimicrobials available are of major concern to patients and the public because of lack of treatment options and potential for spread. AKlebsiella pneumoniaestrain that was nonsusceptible to all tested antibiotics was isolated from a U.S. patient. Mechanisms that could explain all observed phenotypic antimicrobial resistance phenotypes, including resistance to colistin and beta-lactams, were identified through whole-genome sequencing. The large variety of resistance determinants identified demonstrates the usefulness of whole-genome sequencing for detecting these genes in an outbreak response. Sequencing of isolates with rare and unusual phenotypes can provide information on how these extremely resistant isolates develop, including whether resistance is acquired on mobile elements or accumulated through chromosomal mutations. Moreover, this provides further insight into not only detecting these highly resistant organisms but also preventing their spread.

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Analysis of Virulence and Antimicrobial Resistance Gene Carriage in Staphylococcus aureus Infections in Equids Using Whole-Genome Sequencing

mSphere ◽

10.1128/msphere.00196-20 ◽

2021 ◽

Author(s):

Sara V. Little ◽

Andrew E. Hillhouse ◽

Sara D. Lawhon ◽

Laura K. Bryan

Keyword(s):

United States ◽

Staphylococcus Aureus ◽

Antimicrobial Resistance ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

The United States ◽

Whole Genome ◽

Large Collection ◽

Content Type ◽

Antimicrobial Resistance Gene

This is one of the first studies to perform whole-genome sequencing (WGS) of a large collection of Staphylococcus aureus isolates, both methicillin resistant and susceptible, collected from horses. A large proportion of the isolates carry leucocidin PQ (LukPQ), making this one of the first reports of such carriage in the United States.

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Serotype Diversity and Antimicrobial Resistance amongSalmonella entericaIsolates from Patients at an Equine Referral Hospital

Applied and Environmental Microbiology ◽

10.1128/aem.02829-17 ◽

2018 ◽

Vol 84 (13) ◽

pp. e02829-17 ◽

Cited By ~ 3

Author(s):

I. M. Leon ◽

S. D. Lawhon ◽

K. N. Norman ◽

D. S. Threadgill ◽

N. Ohta ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Salmonella Enterica ◽

Referral Hospital ◽

Whole Genome ◽

Content Type ◽

Genes Encoding ◽

Life Threatening ◽

Common Serotypes

ABSTRACTAlthoughSalmonella entericacan produce life-threatening colitis in horses, certain serotypes are more commonly associated with clinical disease. Our aim was to evaluate the proportional morbidity attributed to different serotypes, as well as the phenotypic and genotypic antimicrobial resistance (AMR) ofSalmonellaisolates from patients at an equine referral hospital in the southern United States. A total of 255Salmonellaisolates was obtained from clinical samples of patients admitted to the hospital between 2007 and 2015. Phenotypic resistance to 14 antibiotics surveilled by the U.S. National Antimicrobial Resistance Monitoring System was determined using a commercially available panel. Whole-genome sequencing was used to identify serotypes and genotypic AMR. The most common serotypes wereSalmonella entericaserotype Newport (18%),Salmonella entericaserotype Anatum (15.2%), andSalmonella entericaserotype Braenderup (11.8%). Most (n= 219) of the isolates were pansusceptible, while 25 were multidrug resistant (≥3 antimicrobial classes). Genes encoding beta-lactam resistance, such asblaCMY-2,blaSHV-12,blaCTX-M-27, andblaTEM-1B, were detected. TheqnrB2 andaac(6′)-Ib-crgenes were present in isolates with reduced susceptibility to ciprofloxacin. Genes encoding resistance to gentamicin (aph(3′)-Ia,aac(6′)-IIc), streptomycin (strA andstrB), sulfonamides (sul1), trimethoprim (dfrA), phenicols (catA), tetracyclines [tet(A) andtet(E)], and macrolides [ere(A)] were also identified. The main predicted incompatibility plasmid type was I1 (10%). Core genome-based analyses revealed phylogenetic associations between isolates of common serotypes. The presence of AMRSalmonellain equine patients increases the risk of unsuccessful treatment and causes concern for potential zoonotic transmission to attending veterinary personnel, animal caretakers, and horse owners. Understanding the epidemiology ofSalmonellain horses admitted to referral hospitals is important for the prevention, control, and treatment of salmonellosis.IMPORTANCEIn horses, salmonellosis is a leading cause of life-threatening colitis. At veterinary teaching hospitals, nosocomial outbreaks can increase the risk of zoonotic transmission, lead to restrictions on admissions, impact hospital reputation, and interrupt educational activities. The antimicrobials most often used in horses are included in the 5th revision of the World Health Organization's list of critically important antimicrobials for human medicine. Recent studies have demonstrated a trend of increasing bacterial resistance to drugs commonly used to treatSalmonellainfections. In this study, we identify temporal trends in the distribution ofSalmonellaserotypes and their mechanisms of antimicrobial resistance; furthermore, we are able to determine the likely origin of several temporal clusters of infection by using whole-genome sequencing. These data can be used to focus strategies to better contain the dissemination and enhance the mitigation ofSalmonellainfections and to provide evidence-based policies and guidelines to steward antimicrobial use in veterinary medicine.

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Increased Resistance to Multiple Antimicrobials and Altered Resistance Gene Expression in CMY-2-Positive Salmonella enterica following a Simulated Patient Treatment with Ceftriaxone

Applied and Environmental Microbiology ◽

10.1128/aem.02077-12 ◽

2012 ◽

Vol 78 (22) ◽

pp. 8062-8066 ◽

Cited By ~ 7

Author(s):

Russell D. Hamilton ◽

Holly J. Hulsebus ◽

Samina Akbar ◽

Jeffrey T. Gray

Keyword(s):

Gene Expression ◽

Antimicrobial Resistance ◽

Resistance Gene ◽

Resistance Genes ◽

Salmonella Enterica ◽

The United States ◽

Simulated Patient ◽

Patient Treatment ◽

Content Type

ABSTRACTSalmonellosis is one of the most common causes of food-borne disease in the United States. Increasing antimicrobial resistance and corresponding increases in virulence present serious challenges. Currently, empirical therapy for invasiveSalmonella entericainfection includes either ceftriaxone or ciprofloxacin (E. L. Hohmann, Clin. Infect. Dis. 32:263–269, 2001). TheblaCMY-2gene confers resistance to ceftriaxone, the antimicrobial of choice for pediatric patients with invasiveSalmonella entericainfections, making these infections especially dangerous (J. M. Whichard et al., Emerg. Infect. Dis. 11:1464–1466, 2005). We hypothesized thatblaCMY-2-positiveSalmonella entericawould exhibit increased MICs to multiple antimicrobial agents and increased resistance gene expression following exposure to ceftriaxone using a protocol that simulated a patient treatmentin vitro. SevenSalmonella entericastrains survived a simulated patient treatmentin vitroand, following treatment, exhibited a significantly increased ceftriaxone MIC. Not only would these isolates be less responsive to further ceftriaxone treatment, but because theblaCMY-2genes are commonly located on large, multidrug-resistant plasmids, increased expression of theblaCMY-2gene may be associated with increased expression of other drug resistance genes located on the plasmid (N. D. Hanson and C. C. Sanders, Curr. Pharm. Des. 5:881–894, 1999). The results of this study demonstrate that a simulated patient treatment with ceftriaxone can alter the expression of antimicrobial resistance genes, includingblaCMY-2andfloRinS. entericaserovar Typhimurium andS. entericaserovar Newport. Additionally, we have shown increased MICs following a simulated patient treatment with ceftriaxone for tetracycline, amikacin, ceftriaxone, and cefepime, all of which have resistance genes commonly located on CMY-2 plasmids. The increases in resistance observed are significant and may have a negative impact on both public health and antimicrobial resistance ofSalmonella enterica.

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Frequency of Antimicrobial Resistance Genes in Salmonella From Brazil by in silico Whole-Genome Sequencing Analysis: An Overview of the Last Four Decades

Frontiers in Microbiology ◽

10.3389/fmicb.2020.01864 ◽

2020 ◽

Vol 11 ◽

Author(s):

Grazielle Lima Rodrigues ◽

Pedro Panzenhagen ◽

Rafaela Gomes Ferrari ◽

Anamaria dos Santos ◽

Vania Margaret Flosi Paschoalin ◽

...

Keyword(s):

Antimicrobial Resistance ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Resistance Genes ◽

In Silico ◽

Whole Genome ◽

Sequencing Analysis ◽

Antimicrobial Resistance Genes

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Characterization of SXT/R391 Integrative and Conjugative Elements in Proteus mirabilis Isolates from Food-Producing Animals in China

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02852-15 ◽

2016 ◽

Vol 60 (3) ◽

pp. 1935-1938 ◽

Cited By ~ 25

Author(s):

Chang-Wei Lei ◽

An-Yun Zhang ◽

Hong-Ning Wang ◽

Bi-Hui Liu ◽

Li-Qin Yang ◽

...

Keyword(s):

Escherichia Coli ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Resistance Genes ◽

Proteus Mirabilis ◽

Whole Genome ◽

Content Type ◽

Integrative And Conjugative Elements ◽

Animal Farms

SXT/R391 integrative and conjugative elements (ICEs) were detected in 8 out of 125Proteus mirabilisisolates from food-producing animals in China. Whole-genome sequencing revealed that seven ICEs were identical to ICEPmiJpn1, carrying the cephalosporinase geneblaCMY-2. Another one, designated ICEPmiChn1, carried five resistance genes. All eight ICEs could be transferred toEscherichia colivia conjugation. The results highlight the idea that animal farms are important reservoir of the SXT/R391 ICE-containingP. mirabilis.

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Detecting Staphylococcus aureus Virulence and Resistance Genes: a Comparison of Whole-Genome Sequencing and DNA Microarray Technology

Journal of Clinical Microbiology ◽

10.1128/jcm.03022-15 ◽

2016 ◽

Vol 54 (4) ◽

pp. 1008-1016 ◽

Cited By ~ 25

Author(s):

Lena Strauß ◽

Ulla Ruffing ◽

Salim Abdulla ◽

Abraham Alabi ◽

Ruslan Akulenko ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Dna Microarray ◽

Resistance Genes ◽

In Silico ◽

Target Genes ◽

Whole Genome ◽

Microarray Hybridization ◽

Content Type

Staphylococcus aureusis a major bacterial pathogen causing a variety of diseases ranging from wound infections to severe bacteremia or intoxications. Besides host factors, the course and severity of disease is also widely dependent on the genotype of the bacterium. Whole-genome sequencing (WGS), followed by bioinformatic sequence analysis, is currently the most extensive genotyping method available. To identify clinically relevant staphylococcal virulence and resistance genes in WGS data, we developed anin silicotyping scheme for the software SeqSphere+(Ridom GmbH, Münster, Germany). The implemented target genes (n= 182) correspond to those queried by the IdentibacS. aureusGenotyping DNA microarray (Alere Technologies, Jena, Germany). Thein silicoscheme was evaluated by comparing the typing results of microarray and of WGS for 154 humanS. aureusisolates. A total of 96.8% (n= 27,119) of all typing results were equally identified with microarray and WGS (40.6% present and 56.2% absent). Discrepancies (3.2% in total) were caused by WGS errors (1.7%), microarray hybridization failures (1.3%), wrong prediction of ambiguous microarray results (0.1%), or unknown causes (0.1%). Superior to the microarray, WGS enabled the distinction of allelic variants, which may be essential for the prediction of bacterial virulence and resistance phenotypes. Multilocus sequence typing clonal complexes and staphylococcal cassette chromosomemecelement types inferred from microarray hybridization patterns were equally determined by WGS. In conclusion, WGS may substitute array-based methods due to its universal methodology, open and expandable nature, and rapid parallel analysis capacity for different characteristics in once-generated sequences.

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