1.
Antimicrob Agents Chemother
; 64(5)2020 04 21.
Article
in English
| MEDLINE
| ID: mdl-32041719
ABSTRACT
Addition of sodium bicarbonate (NaHCO3) to standard antimicrobial susceptibility testing medium reveals certain methicillin-resistant Staphylococcus aureus (MRSA) strains to be highly susceptible to ß-lactams. We investigated the prevalence of this phenotype (NaHCO3 responsiveness) to two ß-lactams among 58 clinical MRSA bloodstream isolates. Of note, â¼75% and â¼36% of isolates displayed the NaHCO3 responsiveness phenotype to cefazolin (CFZ) and oxacillin (OXA), respectively. Neither intrinsic ß-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.