Molecular and Proteomic Characterization of Invasive Staphylococcus aureus (ISA) Isolated from Pediatric Bloodstream Infections

Persistent Link:
http://hdl.handle.net/10150/243900
Title:
Molecular and Proteomic Characterization of Invasive Staphylococcus aureus (ISA) Isolated from Pediatric Bloodstream Infections
Author:
Carman, Aubri Sue
Issue Date:
May-2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Staphyloccocus aureus is a Gram-positive cocci and a bacterial pathogen that is ubiquitous and genetically nimble. When untreated, invasive S. aureus infections (ISAs) have a mortality rate that exceeds 20% (1). S. aureus is equipped with a host of virulence determinants that mediate virulence mediated by cell-wall associated proteins and secreted toxins that are, for the most part, genetically regulated. Experiments to characterize the genetic determinants of pathogenicity in pediatric ISAs were undertaken because ISAs in this population remain largely uncharacterized in the current literature. A retrospective chart review identified ISA disease in pediatric patients (0-18 years) at Golisano Children’s Hospital in Syracuse, New York, and at the University of Arizona Medical Center, Diamond Children’s Hospital, Tucson, AZ. Genetic profiling of the bacteria from these pediatric cohorts used methods such as the polymerase chain reaction coupled to electrospray ionization mass spectrometry (PCR-ESI/MS), traditional PCR, and historic phenotypic methods. Isolates were characterized with respect to their genotype (USA strain type and clonal complex) and their common virulence determinants such as Accessory Gene Regulator (agr) type, leukocidins (lukD/E, pvl), hemolysins (hla, hlb, hld), superantigens (sea, tst), and staphylokinase (sak). Genetic profiles were compiled and compared to clinical disease attributes. In New York isolates, the only genes specifically found to be associated with virulence in pediatric ISAs were sea and luk-PV. The Tucson S. aureus isolates did not exhibit the same genetic virulence patterns, illustrating the premise that multiple strains cause invasive infection and that virulence gene expression differs between bacterial populations from geographic locations. Further study of the Arizona isolates focused on the identification of phenol soluble modulins (PSMs), a newly identified determinant of S. aureus virulence. Identification methods for PSMs use liquid chromatography coupled to multiple reaction monitoring mass spectrometry (MRM). Finally, the Bruker SepsiTyper extraction kid and BioTyper software system (MALDI-TOF mass spectrometry) was examined as a novel detection method for rapid, accurate identification of pathogens, including S. aureus, directly from blood culture samples.
Type:
text; Electronic Thesis
Degree Name:
B.S.
Degree Level:
bachelors
Degree Program:
Honors College; Biochemistry and Molecular and Cellular Biology
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleMolecular and Proteomic Characterization of Invasive Staphylococcus aureus (ISA) Isolated from Pediatric Bloodstream Infectionsen_US
dc.creatorCarman, Aubri Sueen_US
dc.contributor.authorCarman, Aubri Sueen_US
dc.date.issued2012-05-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractStaphyloccocus aureus is a Gram-positive cocci and a bacterial pathogen that is ubiquitous and genetically nimble. When untreated, invasive S. aureus infections (ISAs) have a mortality rate that exceeds 20% (1). S. aureus is equipped with a host of virulence determinants that mediate virulence mediated by cell-wall associated proteins and secreted toxins that are, for the most part, genetically regulated. Experiments to characterize the genetic determinants of pathogenicity in pediatric ISAs were undertaken because ISAs in this population remain largely uncharacterized in the current literature. A retrospective chart review identified ISA disease in pediatric patients (0-18 years) at Golisano Children’s Hospital in Syracuse, New York, and at the University of Arizona Medical Center, Diamond Children’s Hospital, Tucson, AZ. Genetic profiling of the bacteria from these pediatric cohorts used methods such as the polymerase chain reaction coupled to electrospray ionization mass spectrometry (PCR-ESI/MS), traditional PCR, and historic phenotypic methods. Isolates were characterized with respect to their genotype (USA strain type and clonal complex) and their common virulence determinants such as Accessory Gene Regulator (agr) type, leukocidins (lukD/E, pvl), hemolysins (hla, hlb, hld), superantigens (sea, tst), and staphylokinase (sak). Genetic profiles were compiled and compared to clinical disease attributes. In New York isolates, the only genes specifically found to be associated with virulence in pediatric ISAs were sea and luk-PV. The Tucson S. aureus isolates did not exhibit the same genetic virulence patterns, illustrating the premise that multiple strains cause invasive infection and that virulence gene expression differs between bacterial populations from geographic locations. Further study of the Arizona isolates focused on the identification of phenol soluble modulins (PSMs), a newly identified determinant of S. aureus virulence. Identification methods for PSMs use liquid chromatography coupled to multiple reaction monitoring mass spectrometry (MRM). Finally, the Bruker SepsiTyper extraction kid and BioTyper software system (MALDI-TOF mass spectrometry) was examined as a novel detection method for rapid, accurate identification of pathogens, including S. aureus, directly from blood culture samples.en_US
dc.typetexten_US
dc.typeElectronic Thesisen_US
thesis.degree.nameB.S.en_US
thesis.degree.levelbachelorsen_US
thesis.degree.disciplineHonors Collegeen_US
thesis.degree.disciplineBiochemistry and Molecular and Cellular Biologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
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