Publications by authors named "Shelby Simar"

The siderophore-cephalosporin cefiderocol (FDC) presents a promising treatment option for carbapenem-resistant (CR) (PA). FDC circumvents traditional porin and efflux-mediated resistance by utilizing TonB-dependent receptors (TBDRs) to access the periplasmic space. Emerging FDC resistance has been associated with loss of function mutations within TBDR genes or the regulatory genes controlling TBDR expression.

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  • * A study of 70 patients revealed that over half had hematological malignancies, with most infections originating from abdominal sources, and a notable 23% mortality rate within 30 days.
  • * Genetic analysis showed diverse NFF strains, low levels of resistance to ampicillin and daptomycin, and higher resistance genes in patients with hematologic cancers compared to those with solid tumors.
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The siderophore-cephalosporin cefiderocol(FDC) presents a promising treatment option for carbapenem-resistant (CR) (PA). FDC circumvents traditional porin and efflux mediated resistance by utilizing TonB-dependent receptors (TBDRs) to access the periplasmic space. Emerging FDC resistance has been associated with loss of function mutations within TBDR genes or the regulatory genes controlling TBDR expression.

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Daptomycin (DAP) is often used as a first-line therapy to treat vancomycin-resistant infections, but emergence of DAP non-susceptibility threatens the effectiveness of this antibiotic. Moreover, current methods to determine DAP minimum inhibitory concentrations (MICs) have poor reproducibility and accuracy. In enterococci, DAP resistance is mediated by the LiaFSR cell membrane stress response system, and deletion of encoding the response regulator results in hypersusceptibility to DAP and antimicrobial peptides.

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Bacterial infection is the most common complication following staged post-mastectomy breast reconstruction initiated with a tissue expander (TE). To limit bacterial infection, antibiotic irrigation of the surgical site is commonly performed despite little high-quality data to support this practice. We performed a prospective randomized control trial to compare the impact of saline irrigation alone to a triple antibiotic irrigation regimen (1 g cefazolin, 80 mg gentamicin, and 50,000 units of bacitracin in 500 mL of saline) for breast implant surgery.

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  • * The study focuses on the LiaFSR system in enterococci, revealing that LiaX acts as a sentinel molecule that recognizes DAP and regulates the cell membrane response, although its function in certain strains is less understood.
  • * An optimized LiaX ELISA was developed to evaluate 86 clinical bloodstream infection isolates, finding that elevated LiaX levels correlate with DAP resistance, even in some strains that test susceptible by standard methods, suggesting a need to
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  • In the U.S., resistance to vancomycin in enterococci is uncommon, but this study identified three cases of ST6 vancomycin-resistant Enterococcus faecalis causing infections (bacteremia) in different patients and locations.* -
  • The specific isolates were obtained between 2018 and 2020 from Miami, FL, and Houston, TX, indicating a possible trend in resistance emergence in these areas.* -
  • The isolates contained a gene cluster within a transposon that suggests multiple introductions into the ST6 E. faecalis strain over time.*
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Background: Vancomycin-resistant enterococci (VRE) are major therapeutic challenges. Prospective contemporary data characterizing the clinical and molecular epidemiology of VRE bloodstream infections (BSIs) are lacking.

Methods: The Vancomycin-Resistant Enterococcal BSI Outcomes Study (VENOUS I) is a prospective observational cohort of adult patients with enterococcal BSI in 11 US hospitals.

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Purpose Of Review: The advancement of molecular techniques such as whole-genome sequencing (WGS) has revolutionized the field of bacterial strain typing, with important implications for epidemiological surveillance and outbreak investigations. This review summarizes state-of-the-art techniques in strain typing and examines barriers faced by clinical and public health laboratories in implementing these new methodologies.

Recent Findings: WGS-based methodologies are on track to become the new 'gold standards' in bacterial strain typing, replacing traditional methods like pulsed-field gel electrophoresis and multilocus sequence typing.

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Though rare, breast implant-associated anaplastic large cell lymphoma (BIA-ALCL), a CD30+ T-cell lymphoma associated with textured breast implants, has adversely impacted our perception of the safety of breast implants. Its etiology unknown, one hypothesis suggests an initiating inflammatory stimulus, possibly infectious, triggers BIA-ALCL. We analyzed microbiota of breast, skin, implant and capsule in BIA-ALCL patients (n = 7), and controls via culturing methods, 16S rRNA microbiome sequencing, and immunohistochemistry.

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Background: A reliable method of polymyxin B and E (colistin) susceptibility testing remains elusive. These drugs diffuse poorly into agar, creating potentially inaccurate Etest and disk diffusion results, and testing by these methods is not recommended. Broth microdilution is the reference testing method, although it can be sometimes difficult to interpret.

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Polymyxin resistance is an increasing problem worldwide. Currently, determining susceptibility to polymyxins is problematic and lengthy. Polymyxins diffuse poorly into agar, potentially giving inaccurate disk diffusion and Etest results.

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Vibrio vulnificus, an inhabitant of marine and estuarine environments around the world, is the leading cause of reported seafood-related deaths in the United States. Disease is caused by opaque colony-forming strains that produce capsular polysaccharide, loss of which results in an unencapsulated translucent phenotype with diminished virulence potential. Rugose is a third phenotypic variant of V.

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