scholarly journals Emergence and Within-Host Genetic Evolution of Methicillin-ResistantStaphylococcus aureusResistant to Linezolid in a Cystic Fibrosis Patient

2018 ◽  
Vol 62 (12) ◽  
Author(s):  
Caroline Rouard ◽  
Fabien Garnier ◽  
Jeremy Leraut ◽  
Margaux Lepainteur ◽  
Lalaina Rahajamananav ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Generation Time ◽  
Strong Increase ◽  
Whole Genome ◽  
Content Type ◽  
Mrsa Infection ◽  
Host Genetic ◽  
Mrsa Strains

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) infection has increased in recent years among cystic fibrosis (CF) patients. Linezolid (LZD) is one of the antistaphylococcal antibiotics widely used in this context. Although LZD resistance is rare, it has been described as often associated with long-term treatments. Thirteen MRSA strains isolated over 5 years from one CF patient were studied for LZD resistance emergence and subjected to whole-genome sequencing (WGS). Resistance emerged after three 15-day LZD therapeutic regimens over 4 months. It was associated with the mutation of G to T at position 2576 (G2576T) in all 5rrlcopies, along with a very high MIC (>256 mg/liter) and a strong increase in the generation time. Resistant strains isolated during the ensuing LZD therapeutic regimens and until 13 months after LZD stopped harbored only 3 or 4 mutatedrrlcopies, associated with lower MICs (8 to 32 mg/liter) and low to moderate generation time increases. Despite these differences, whole-genome sequencing allowed us to determine that all isolates, including the susceptible one isolated before LZD treatment, belonged to the same lineage. In conclusion, LZD resistance can emerge rapidly in CF patients and persist without linezolid selective pressure in colonizing MRSA strains belonging to the same lineage.

scholarly journals High-Level Antibiotic Tolerance of a Clinically Isolated Enterococcus faecalis Strain

2020 ◽  
Vol 87 (1) ◽  
Author(s):  
Huan Gu ◽  
Sweta Roy ◽  
Xiaohui Zheng ◽  
Tian Gao ◽  
Huilin Ma ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Whole Genome Sequencing ◽  
Cystic Fibrosis Patient ◽  
Enterococcus Faecalis ◽  
Antibiotic Treatment ◽  
Genome Sequencing ◽  
Efflux Pump ◽  
Whole Genome ◽  
Content Type ◽  
High Level

ABSTRACT Bacteria can survive antibiotic treatment both by acquiring antibiotic resistance genes and through mechanisms of tolerance that are based on phenotypic changes and the formation of metabolically inactive cells. Here, we report an Enterococcus faecalis strain (E. faecalis UM001B) that was isolated from a cystic fibrosis patient and had no increase in resistance but extremely high-level tolerance to ampicillin, vancomycin, and tetracycline. Specifically, the percentages of cells that survived 3.5-h antibiotic treatment (at 100 μg · ml−1) were 25.4% ± 4.3% and 51.9% ± 4.0% for ampicillin and tetracycline, respectively; vancomycin did not exhibit any significant killing. Consistent with the changes in antibiotic susceptibility, UM001B was found to have reduced penetration of ampicillin and vancomycin and accumulation of tetracycline compared to the reference strain ATCC 29212. Based on whole-genome sequencing, four amino acid substitutions were identified in one of the tetracycline efflux pump repressors (TetRs), compared to ATCC 29212. Results of molecular simulations and experimental assays revealed that these mutations could lead to higher levels of tetracycline efflux activity. Consistently, replicating these mutations in Escherichia coli MG1655 increased its tolerance to tetracycline. Overall, these findings provide new insights into the development of multidrug tolerance in E. faecalis, which can facilitate future studies to better control enterococcal infections. IMPORTANCE Enterococcus faecalis represents a major group of pathogens causing nosocomial infections that are resistant to multiple classes of antibiotics. An important challenge associated with E. faecalis infection is the emergence of multidrug-tolerant strains, which have normal MICs but do not respond to antibiotic treatment. Here, we report a strain of E. faecalis that was isolated from a cystic fibrosis patient and demonstrated high-level tolerance to ampicillin, vancomycin, and tetracycline. Whole-genome sequencing revealed critical substitutions in one of the tetracycline efflux pump repressors that are consistent with the increased tolerance of E. faecalis UM001B to tetracycline. These findings provide new information about bacterial antibiotic tolerance and may help develop more effective therapeutics.

scholarly journals Carriage of a Single Strain of NontoxigenicCorynebacterium diphtheriaebv. Belfanti (Corynebacterium belfantii) in Four Patients with Cystic Fibrosis

2019 ◽  
Vol 57 (5) ◽  
Author(s):  
Diane Pivot ◽  
Annlyse Fanton ◽  
Edgar Badell-Ocando ◽  
Marion Benouachkou ◽  
Karine Astruc ◽  
...  
Keyword(s):  
Cystic Fibrosis ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Antimicrobial Agents ◽  
Care Center ◽  
Whole Genome ◽  
Single Strain ◽  
Content Type ◽  
Microbiological Methods ◽  
Cross Transmission

ABSTRACTCystic fibrosis (CF) patients are commonly colonized by bacterial pathogens, which can induce persistent lung inflammation and may contribute to clinical deterioration. Colonization of CF patients and cross-transmission byCorynebacterium diphtheriaehave not been reported so far. The aim of this article was to investigate the possibility of a cross-transmission ofC. diphtheriaebiovar Belfanti between four patients of a CF center.C. diphtheriaebiovar Belfanti (now formally calledC. belfantii) isolates were collected from four patients in a single CF care center over a period of 6 years and analyzed by microbiological methods and whole-genome sequencing. Epidemiological links among patients were investigated. Ten isolates were collected from 4 patients. Whole-genome sequencing of one isolate from each patient showed that a single strain was shared among them. In addition, one patient was found to have the same strain in two consecutive samplings performed 9 months apart. The strain was nontoxigenic and was susceptible to most antimicrobial agents. Ciprofloxacin resistance was observed in one patient. The idea of transmission of the strain among patients was supported by the occurrence of same-day visits to the CF center. This study demonstrated colonization of CF patients byC. diphtheriaebiovar Belfanti (C. belfantii), and the data suggest persistence and transmission of a unique strain during at least 6 years in a single CF patient care center.

scholarly journals Clostridioides difficile Whole-Genome Sequencing Reveals Limited Within-Host Genetic Diversity in a Pediatric Cohort

2019 ◽  
Vol 57 (9) ◽  
Author(s):  
Aakash Balaji ◽  
Egon A. Ozer ◽  
Larry K. Kociolek
Keyword(s):  
Genetic Diversity ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Core Genome ◽  
Genetic Relatedness ◽  
The Other ◽  
Whole Genome ◽  
Content Type ◽  
Clostridioides Difficile ◽  
Host Genetic

ABSTRACT Whole-genome sequencing (WGS) is a highly sensitive method for identifying genetic relatedness and transmission of Clostridioides difficile strains. Previous studies suggest that as few as 3 core genome single-nucleotide variants (SNVs) discriminate between genetically distinct isolates. Because a single C. difficile colony is selected from culture for WGS, significant within-host genetic diversity could preclude identification of transmission events. To evaluate the likelihood of missed transmission events using WGS of single colonies from culture, we examined within-host genetic diversity among C. difficile isolates collected from children. We performed WGS using an Illumina MiSeq instrument on 8 C. difficile colonies randomly selected from each culture performed on stool collected from 10 children (8 children diagnosed with C. difficile infection and 2 children with asymptomatic carriage); 77/80 (96%) isolate sequences were successfully assembled. Among 8/10 (80%) children, all isolates were the same sequence type (ST). The other 2 children each had mixed infection with two STs, although one ST predominated. Among 9/10 (90%) children, isotypic isolates differed by ≤2 SNVs; an isotypic isolate in the remaining child differed by 3 to SNVs relative to the other isolates from that child. Overall, among the 77 isolates collected from 10 stool cultures, 74/77 (96%) were clonal (i.e., same ST and ≤2 core genome SNVs) to other isolates in stool culture. In summary, we identified rare C. difficile within-host genetic diversity in children, suggesting that WGS of a single colony from stool is likely to appropriately characterize isolate clonality and putative transmission events in the majority of cases.

scholarly journals Population Dynamics of Staphylococcus aureus in Cystic Fibrosis Patients To Determine Transmission Events by Use of Whole-Genome Sequencing

2017 ◽  
Vol 55 (7) ◽  
pp. 2143-2152 ◽  
Author(s):  
Andrea Ankrum ◽  
Barry G. Hall
Keyword(s):  
Cystic Fibrosis ◽  
Staphylococcus Aureus ◽  
Population Dynamics ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Phylogenetic Trees ◽  
Hospital Environment ◽  
Snp Analysis ◽  
Whole Genome ◽  
Content Type

ABSTRACT Strict infection control practices have been implemented for health care visits by cystic fibrosis (CF) patients in an attempt to prevent transmission of important pathogens. This study used whole-genome sequencing (WGS) to determine strain relatedness and assess population dynamics of Staphylococcus aureus isolates from a cohort of CF patients as assessed by strain relatedness. A total of 311 S. aureus isolates were collected from respiratory cultures of 115 CF patients during a 22-month study period. Whole-genome sequencing was performed, and using single nucleotide polymorphism (SNP) analysis, phylogenetic trees were assembled to determine relatedness between isolates. Methicillin-resistant Staphylococcus aureus (MRSA) phenotypes were predicted using PPFS2 and compared to the observed phenotype. The accumulation of SNPs in multiple isolates obtained over time from the same patient was examined to determine if a genomic molecular clock could be calculated. Pairs of isolates with ≤71 SNP differences were considered to be the “same” strain. All of the “same” strain isolates were either from the same patient or siblings pairs. There were 47 examples of patients being superinfected with an unrelated strain. The predicted MRSA phenotype was accurate in all but three isolates. Mutation rates were unable to be determined because the branching order in the phylogenetic tree was inconsistent with the order of isolation. The observation that transmissions were identified between sibling patients shows that WGS is an effective tool for determining transmission between patients. The observation that transmission only occurred between siblings suggests that Staphylococcus aureus acquisition in our CF population occurred outside the hospital environment and indicates that current infection prevention efforts appear effective.

scholarly journals Whole-Genome Sequence of Chryseobacterium oranimense, a Colistin-Resistant Bacterium Isolated from a Cystic Fibrosis Patient in France

2015 ◽  
Vol 59 (3) ◽  
pp. 1696-1706 ◽  
Author(s):  
Poonam Sharma ◽  
Sushim Kumar Gupta ◽  
Seydina M. Diene ◽  
Jean-Marc Rolain
Keyword(s):  
Cystic Fibrosis ◽  
Antibiotic Resistance ◽  
Whole Genome Sequencing ◽  
Cystic Fibrosis Patient ◽  
Genome Sequencing ◽  
Genome Sequence ◽  
Resistant Bacterium ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Content Type

ABSTRACTFor the first time, we report the whole-genome sequence analysis ofChryseobacterium oranimenseG311, a multidrug-resistant bacterium, from a cystic fibrosis patient in France, including resistance to colistin. Whole-genome sequencing ofC. oranimenseG311 was performed using Ion Torrent PGM, and RAST, the EMBL-EBI server, and the Antibiotic Resistance Gene-ANNOTation (ARG-ANNOT) database were used for annotation of all genes, including antibiotic resistance (AR) genes. General features of theC. oranimenseG311 draft genome were compared to the other available genomes ofChryseobacterium gleumandChryseobacteriumsp. strain CF314.C. oranimenseG311 was found to be resistant to all β-lactams, including imipenem, and to colistin. The genome size ofC. oranimenseG311 is 4,457,049 bp in length, with 37.70% GC content. We found 27 AR genes in the genome, including β-lactamase genes which showed little similarity to the known β-lactamase genes and could likely be novel. We found the type I polyketide synthase operon followed by a zeaxanthin glycosyltransferase gene in the genome, which could impart the yellow pigmentation of the isolate. We located the O-antigen biosynthesis cluster, and we also discovered a novel capsular polysaccharide biosynthesis cluster. We also found known mutations in the orthologs of thepmrA(E8D),pmrB(L208F and P360Q), andlpxA(G68D) genes. We speculate that the presence of the capsular cluster and mutations in these genes could explain the resistance of this bacterium to colistin. We demonstrate that whole-genome sequencing was successfully applied to decipher the resistome of a multidrug resistance bacterium associated with cystic fibrosis patients.

scholarly journals Expanding U.S. Laboratory Capacity for Neisseria gonorrhoeae Antimicrobial Susceptibility Testing and Whole-Genome Sequencing through the CDC's Antibiotic Resistance Laboratory Network

2020 ◽  
Vol 58 (4) ◽  
Author(s):  
Ellen N. Kersh ◽  
Cau D. Pham ◽  
John R. Papp ◽  
Robert Myers ◽  
Richard Steece ◽  
...  
Keyword(s):  
Public Health ◽  
Antibiotic Resistance ◽  
Neisseria Gonorrhoeae ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Antimicrobial Susceptibility ◽  
Susceptibility Testing ◽  
Whole Genome ◽  
Content Type ◽  
Laboratory Capacity

ABSTRACT U.S. gonorrhea rates are rising, and antibiotic-resistant Neisseria gonorrhoeae (AR-Ng) is an urgent public health threat. Since implementation of nucleic acid amplification tests for N. gonorrhoeae identification, the capacity for culturing N. gonorrhoeae in the United States has declined, along with the ability to perform culture-based antimicrobial susceptibility testing (AST). Yet AST is critical for detecting and monitoring AR-Ng. In 2016, the CDC established the Antibiotic Resistance Laboratory Network (AR Lab Network) to shore up the national capacity for detecting several resistance threats including N. gonorrhoeae. AR-Ng testing, a subactivity of the CDC’s AR Lab Network, is performed in a tiered network of approximately 35 local laboratories, four regional laboratories (state public health laboratories in Maryland, Tennessee, Texas, and Washington), and the CDC’s national reference laboratory. Local laboratories receive specimens from approximately 60 clinics associated with the Gonococcal Isolate Surveillance Project (GISP), enhanced GISP (eGISP), and the program Strengthening the U.S. Response to Resistant Gonorrhea (SURRG). They isolate and ship up to 20,000 isolates to regional laboratories for culture-based agar dilution AST with seven antibiotics and for whole-genome sequencing of up to 5,000 isolates. The CDC further examines concerning isolates and monitors genetic AR markers. During 2017 and 2018, the network tested 8,214 and 8,628 N. gonorrhoeae isolates, respectively, and the CDC received 531 and 646 concerning isolates and 605 and 3,159 sequences, respectively. In summary, the AR Lab Network supported the laboratory capacity for N. gonorrhoeae AST and associated genetic marker detection, expanding preexisting notification and analysis systems for resistance detection. Continued, robust AST and genomic capacity can help inform national public health monitoring and intervention.

scholarly journals Tracing Melioidosis Back to the Source: Using Whole-Genome Sequencing To Investigate an Outbreak Originating from a Contaminated Domestic Water Supply

2015 ◽  
Vol 53 (4) ◽  
pp. 1144-1148 ◽  
Author(s):  
Evan McRobb ◽  
Derek S. Sarovich ◽  
Erin P. Price ◽  
Mirjam Kaestli ◽  
Mark Mayo ◽  
...  
Keyword(s):  
Water Supply ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Clinical Isolates ◽  
Whole Genome ◽  
Northern Australia ◽  
Source Attribution ◽  
Environmental Strain ◽  
Content Type ◽  
Groundwater Supply

Melioidosis, a disease of public health importance in Southeast Asia and northern Australia, is caused by the Gram-negative soil bacillusBurkholderia pseudomallei. Melioidosis is typically acquired through environmental exposure, and case clusters are rare, even in regions where the disease is endemic.B. pseudomalleiis classed as a tier 1 select agent by the Centers for Disease Control and Prevention; from a biodefense perspective, source attribution is vital in an outbreak scenario to rule out a deliberate release. Two cases of melioidosis within a 3-month period at a residence in rural northern Australia prompted an investigation to determine the source of exposure.B. pseudomalleiisolates from the property's groundwater supply matched the multilocus sequence type of the clinical isolates. Whole-genome sequencing confirmed the water supply as the probable source of infection in both cases, with the clinical isolates differing from the likely infecting environmental strain by just one single nucleotide polymorphism (SNP) each. For the first time, we report a phylogenetic analysis of genomewide insertion/deletion (indel) data, an approach conventionally viewed as problematic due to high mutation rates and homoplasy. Our whole-genome indel analysis was concordant with the SNP phylogeny, and these two combined data sets provided greater resolution and a better fit with our epidemiological chronology of events. Collectively, this investigation represents a highly accurate account of source attribution in a melioidosis outbreak and gives further insight into a frequently overlooked reservoir ofB. pseudomallei. Our methods and findings have important implications for outbreak source tracing of this bacterium and other highly recombinogenic pathogens.

scholarly journals Putative Integrative Mobile Elements That Exploit the Xer Recombination Machinery Carrying blaIMI-Type Carbapenemase Genes in Enterobacter cloacae Complex Isolates in Singapore

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
Tse H. Koh ◽  
Nurdyana Binte Abdul Rahman ◽  
Jeanette W. P. Teo ◽  
My-Van La ◽  
Balamurugan Periaswamy ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Multilocus Sequence Typing ◽  
Enterobacter Cloacae ◽  
Mobile Elements ◽  
Whole Genome ◽  
Content Type ◽  
Flanking Regions ◽  
Enterobacter Cloacae Complex

ABSTRACT Whole-genome sequencing was performed on 16 isolates of the carbapenemase-producing Enterobacter cloacae complex to determine the flanking regions of bla IMI-type genes. Phylogenetic analysis of multilocus sequence typing (MLST) targets separated the isolates into 4 clusters. The bla IMI-type genes were all found on Xer-dependent integrative mobile elements (IMEX). The IMEX elements of 5 isolates were similar to those described in Canada, while the remainder were novel. Five isolates had IMEX elements lacking a resolvase and recombinase.

scholarly journals Whole-Genome Sequencing Confirms that Burkholderia pseudomallei Multilocus Sequence Types Common to Both Cambodia and Australia Are Due to Homoplasy

2014 ◽  
Vol 53 (1) ◽  
pp. 323-326 ◽  
Author(s):  
Birgit De Smet ◽  
Derek S. Sarovich ◽  
Erin P. Price ◽  
Mark Mayo ◽  
Vanessa Theobald ◽  
...  
Keyword(s):  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Genome Analysis ◽  
Burkholderia Pseudomallei ◽  
Whole Genome ◽  
Whole Genome Analysis ◽  
Content Type ◽  
Sequence Types

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.

scholarly journals Whole-Genome Sequencing Allows for Improved Identification of Persistent Listeria monocytogenes in Food-Associated Environments

2015 ◽  
Vol 81 (17) ◽  
pp. 6024-6037 ◽  
Author(s):  
Matthew J. Stasiewicz ◽  
Haley F. Oliver ◽  
Martin Wiedmann ◽  
Henk C. den Bakker
Keyword(s):  
Listeria Monocytogenes ◽  
Whole Genome Sequencing ◽  
Genome Sequencing ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Genetic Determinants ◽  
Single Nucleotide ◽  
Content Type ◽  
Food Borne ◽  
Clonal Spread

ABSTRACTWhile the food-borne pathogenListeria monocytogenescan persist in food associated environments, there are no whole-genome sequence (WGS) based methods to differentiate persistent from sporadic strains. Whole-genome sequencing of 188 isolates from a longitudinal study ofL. monocytogenesin retail delis was used to (i) apply single-nucleotide polymorphism (SNP)-based phylogenetics for subtyping ofL. monocytogenes, (ii) use SNP counts to differentiate persistent from repeatedly reintroduced strains, and (iii) identify genetic determinants ofL. monocytogenespersistence. WGS analysis revealed three prophage regions that explained differences between three pairs of phylogenetically similar populations with pulsed-field gel electrophoresis types that differed by ≤3 bands. WGS-SNP-based phylogenetics found that putatively persistentL. monocytogenesrepresent SNP patterns (i) unique to a single retail deli, supporting persistence within the deli (11 clades), (ii) unique to a single state, supporting clonal spread within a state (7 clades), or (iii) spanning multiple states (5 clades). Isolates that formed one of 11 deli-specific clades differed by a median of 10 SNPs or fewer. Isolates from 12 putative persistence events had significantly fewer SNPs (median, 2 to 22 SNPs) than between isolates of the same subtype from other delis (median up to 77 SNPs), supporting persistence of the strain. In 13 events, nearly indistinguishable isolates (0 to 1 SNP) were found across multiple delis. No individual genes were enriched among persistent isolates compared to sporadic isolates. Our data show that WGS analysis improves food-borne pathogen subtyping and identification of persistent bacterial pathogens in food associated environments.

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