Cryptococcus neoformans is a haploid environmental organism and the major cause of fungal meningoencephalitis in AIDS patients. Fluconazole (FLC), a triazole, is widely used for the maintenance therapy of cryptococcosis. Heteroresistance to FLC, an adaptive mode of azole resistance, was associated with FLC therapy failure cases but the mechanism underlying the resistance was unknown. We used co...

The recent identification of glycopeptide intermediate-resistant Staphylococcus aureus (GISA) clinical isolates has provided an opportunity to assess the stability of the glycopeptide resistance phenotype by nonselective serial passage and to evaluate reversion-associated cell surface changes. Three GISA isolates from the United States (MIC of vancomycin = 8 microg/ml) and two from Japan (MICs ...

OBJECTIVES To evaluate microbiological properties of methicillin-resistant Staphylococcus aureus (MRSA) during prolonged vancomycin therapy. METHODS We evaluated vancomycin susceptibility and heteroresistance, accessory gene regulator (agr) function, autolysis, biofilm production and in vitro vancomycin killing in serial MRSA bloodstream isolates obtained over a 30 month period from a patient...

We have previously reported the establishment of a Staphylococcus aureus laboratory strain, 10 3d1, having reduced susceptibility to daptomycin and heterogeneous vancomycin-intermediate S. aureus (VISA) phenotype. The strain was generated in vitro by serial daptomycin selection (Camargo, I. L., H. M. Neoh, L. Cui, and K. Hiramatsu, Antimicrob. Agents Chemother. 52:4289-4299, 2008). Here we expl...

A comprehensive understanding of the mechanisms by which Staphylococcus aureus achieves intermediate levels of resistance to vancomycin could foster the development of improved diagnostic tests and therapeutic agents, with potentially improved clinical outcomes. Vidaillac et al, in this issue of the Journal [1], used well-characterized successive S. aureus clinical isolates that had acquired se...

Background: Haemophilus influenzae β-lactam resistance is mediated by production of β-lactamase and mutations in penicillin-binding protein 3 (PBP3, encoded ftsI). Only one the 646 patient-unique H. isolated our laboratory between 2012–July 2022 was meropenem (amoxicillin, co-amoxiclav ceftriaxone) resistant. Methods: Identification susceptibility this meropenem-resistant (MRHI) confirmed disk ...