Open AccessClinical and Microbiological Characteristics of Heteroresistant and Vancomycin-Intermediate Staphylococcus aureus from Bloodstream Infections in a Brazilian Teaching Hospital
Author(s) -
Thaina Miranda da Costa,
Priscylla Guimarães Migueres Morgado,
Fernanda Sampaio Cavalcante,
Andreia Paredes Damasco,
Simone Aranha Nouér,
Kátia Regietto dos Santos
Publication year - 2016
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0160506
Subject(s) - sccmec , microbiology and biotechnology , broth microdilution , etest , staphylococcus aureus , multilocus sequence typing , methicillin resistant staphylococcus aureus , pulsed field gel electrophoresis , vancomycin , population , daptomycin , biology , medicine , minimum inhibitory concentration , antibiotics , bacteria , genotype , biochemistry , environmental health , gene , genetics
This study analyzed clinical and microbiological characteristics of heteroresistant (hVISA) and vancomycin-intermediate Staphylococcus aureus (VISA) from bloodstream infections (BSI) in a Brazilian teaching hospital, between 2011 and 2013. Minimum inhibitory concentrations (MIC) of antimicrobials were determined by broth microdilution method and SCC mec was detected by PCR. Isolates with a vancomycin MIC ≥ 2mg/L were cultured on BHI agar with 3, 4 or 6 mg/L (BHIa3, BHIa4 or BHIa6) of vancomycin and BHIa4 with casein (BHIa4ca). Macromethod Etest ® and Etest ® Glicopeptides Resistance Detection were also used. VISA and hVISA isolates were confirmed by the population analysis profile then typed by pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing. Medical data from the patients were obtained from their medical records. Among 110 consecutive isolates, 31 (28%) were MRSA and carried the SCC mec type II (15 isolates) or IV (16 isolates). Vancomycin MIC 50 and MIC 90 were 1 and 2 mg/L, respectively. MRSA isolates had increased non-susceptibility to daptomycin ( p = 0.0003). Six (5%) isolates were VISA, four of which were MRSA, three SCC mec type II/USA100/ST5 and one type IV/USA800/ST3192. One MRSA SCC mec II isolate grew on agar BHIa3, BHIa4 and BHIa4ca, and it was confirmed as hVISA. Among the six VISA isolates, five (83%) grew on BHIa3 and three (50%) on BHI4ca. Four of the six VISA isolates and the one hVISA isolate were from patients who had undergone dialysis. Thus, a possible dissemination of the SCC mec II/USA100/ST5 lineage may have occurred in the hospital comprising the VISA, hVISA and daptomycin non-susceptible S . aureus Brazilian isolates from health care associated bloodstream infections.