Scope and Predictive Genetic/Phenotypic Signatures of Bicarbonate (NaHCO3) Responsiveness and β-Lactam Sensitization in Methicillin-Resistant Staphylococcus aureus.

Journal Article (Journal Article)

Addition of sodium bicarbonate (NaHCO3) to standard antimicrobial susceptibility testing medium reveals certain methicillin-resistant Staphylococcus aureus (MRSA) strains to be highly susceptible to β-lactams. We investigated the prevalence of this phenotype (NaHCO3 responsiveness) to two β-lactams among 58 clinical MRSA bloodstream isolates. Of note, ∼75% and ∼36% of isolates displayed the NaHCO3 responsiveness phenotype to cefazolin (CFZ) and oxacillin (OXA), respectively. Neither intrinsic β-lactam MICs in standard Mueller-Hinton broth (MHB) nor population analysis profiles were predictive of this phenotype. Several genotypic markers (clonal complex 8 [CC8]; agr I and spa t008) were associated with NaHCO3 responsiveness for OXA.

Full Text

Duke Authors

Cited Authors

  • Ersoy, SC; Otmishi, M; Milan, VT; Li, L; Pak, Y; Mediavilla, J; Chen, L; Kreiswirth, B; Chambers, HF; Proctor, RA; Xiong, YQ; Fowler, VG; Bayer, AS

Published Date

  • April 21, 2020

Published In

Volume / Issue

  • 64 / 5

PubMed ID

  • 32041719

Pubmed Central ID

  • PMC7179597

Electronic International Standard Serial Number (EISSN)

  • 1098-6596

Digital Object Identifier (DOI)

  • 10.1128/AAC.02445-19


  • eng

Conference Location

  • United States