title: Is prediffusion test an alternative to improve accuracy in screening hVISA strains and to detect susceptibility to glycopeptides/lipopeptides?
abstract: The characterization of heteroresistant vancomycin-intermediate Staphylococcus aureus strains (hVISA) is even more challenging, as no routine standardized laboratory methods are available. A total of 124 S. aureus isolates recovered from inpatients attended in hospitals of Santa Catarina State, Southern Brazil, were evaluated. The MIC of vancomycin, teicoplanin, and daptomycin was determined by Etest and prediffusion tests using NeoSensitabs® tablets. All isolates were susceptible to vancomycin (MICs: 0.5-3 μg/mL) by Etest. However, according to prediffusion test, 17 isolates presented reduced susceptibility to vancomycin, and of these, 12 were confirmed as hVISA using populational analysis. Considering daptomycin, prediffusion results were in agreement with susceptibility data (MICs), as all isolates were susceptible. Considering that characterizing hVISA is challenging and that MIC determination is not adequate to characterize this phenotype, prediffusion test was a viable alternative to screening hVISA and reduced susceptibility to vancomycin. It was simple and low cost, with accuracy comparable to other well-established methods.
authors.affiliation: Federal University of Health Sciences of Porto Alegre, RS, Brazil; University Regional of Blumenau, SC, Brazil. Electronic address: alessandrocosilveira@gmail.com.
authors.forename: Alessandro Conrado de Oliveira
authors.initials: AC
authors.lastname: Silveira
authors.affiliation: Federal University of Health Sciences of Porto Alegre, RS, Brazil.
authors.forename: Gustavo Enck
authors.initials: GE
authors.lastname: Sambrano
authors.affiliation: Federal University of Health Sciences of Porto Alegre, RS, Brazil.
authors.forename: Thiago Galvão da Silva
authors.initials: TG
authors.lastname: Paim
authors.affiliation: Federal University of Health Sciences of Porto Alegre, RS, Brazil.
authors.forename: Juliana
authors.initials: J
authors.lastname: Caierão
authors.affiliation: University Regional of Blumenau, SC, Brazil.
authors.forename: Caio Mauricio Mendes de
authors.initials: CM
authors.lastname: Cordova
authors.affiliation: Federal University of Health Sciences of Porto Alegre, RS, Brazil.
authors.forename: Pedro Alves
authors.initials: PA
authors.lastname: d'Azevedo
mesh_terms: D052978:Disk Diffusion Antimicrobial Tests; D006020:Glycopeptides / Q000494:pharmacology*; D006801:Humans; D055666:Lipopeptides / Q000494:pharmacology*; D008826:Microbial Sensitivity Tests / Q000379:methods; D015203:Reproducibility of Results; D013203:Staphylococcal Infections / Q000175:diagnosis / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000187:drug effects* / Q000302:isolation & purification; D020713:Vancomycin Resistance
chemical_list: D006020:Glycopeptides; D055666:Lipopeptides
keywords: Heteroresistant vancomycin intermediate; MRSA; Staphylococcus aureus; Vancomycin resistance