title: Comparative whole genome sequencing of community-associated methicillin-resistant Staphylococcus aureus sequence type 8 from primary care clinics in a Texas community.
abstract: OBJECTIVE
  Our understanding of the molecular dynamics driving the community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) epidemic at the whole genome level is limited. We sought to assess the use of whole genome sequencing (WGS) to evaluate the genomic diversity and genotypic prediction of antimicrobial resistance of CA-MRSA isolates from patients in South Texas.
  
  
  METHODS
  Comparative whole genome sequencing.
  Thirteen clinical CA-MRSA isolates recovered from patients presenting with skin and soft tissue infections to nine primary care clinics in the South Texas Ambulatory Research Network between 2010 and 2013.
  
  
  RESULTS
  Comparative WGS was performed on the 13 MRSA sequence type 8 clinical isolates. We compared the resistome of genes encoding for antibiotic resistance with a phenotypically derived antibiogram using standard antimicrobial susceptibility testing. The strains differed by an average of 72 single nucleotide polymorphisms (SNPs) per isolate in the core genome compared with FPR3757 (USA300, reference strain). There were a total of 623 unique SNPs in the core genome (range 47-88 SNPs per isolate). We identified 19 nonsynonymous SNPs in genes encoding proven or putative S. aureus virulence determinants in the core genome. There was complete concordance between genotypic evidence for antimicrobial resistance and the phenotypically derived antibiogram.
  
  
  CONCLUSIONS
  Overall, although these CA-MRSA isolates were similar on the level of clonal type, clinical syndrome, and geographic area, the strains were diverse at the genome level. Furthermore, our findings provide important proof-of-concept information for using WGS as a potential front-end screening tool for antimicrobial resistance predictions.
authors: College of Pharmacy, The University of Texas at Austin, Austin, Texas; School of Medicine, The University of Texas Health Science Center, San Antonio, Texas.
authors: Grace C
authors: GC
authors: Lee
authors: S Wesley
authors: SW
authors: Long
authors: James M
authors: JM
authors: Musser
authors: Stephen B
authors: SB
authors: Beres
authors: Randall J
authors: RJ
authors: Olsen
authors: Steven D
authors: SD
authors: Dallas
authors: Yury O
authors: YO
authors: Nunez
authors: Christopher R
authors: CR
authors: Frei
mesh_terms: D000328:Adult; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D002648:Child; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D005260:Female; D016680:Genome, Bacterial; D005838:Genotype; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010865:Pilot Projects; D020641:Polymorphism, Single Nucleotide; D011320:Primary Health Care; D013207:Staphylococcal Skin Infections / Q000188:drug therapy / Q000382:microbiology*; D013781:Texas; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents
keywords: Staphylococcus aureus; antimicrobial resistance; phylogeny; whole genome sequencing