title: Clinical and Microbiological Characteristics of Heteroresistant and Vancomycin-Intermediate Staphylococcus aureus from Bloodstream Infections in a Brazilian Teaching Hospital.
abstract: 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 SCCmec 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 SCCmec type II (15 isolates) or IV (16 isolates). Vancomycin MIC50 and MIC90 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 SCCmec type II/USA100/ST5 and one type IV/USA800/ST3192. One MRSA SCCmec 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 SCCmec 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.
authors: Laboratório de Infecção Hospitalar, Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Thaina Miranda
authors: TM
authors: da Costa
authors: Laboratório de Infecção Hospitalar, Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Priscylla Guimarães Migueres
authors: PG
authors: Morgado
authors: Laboratório de Infecção Hospitalar, Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Fernanda Sampaio
authors: FS
authors: Cavalcante
authors: Laboratório de Infecção Hospitalar, Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Andreia Paredes
authors: AP
authors: Damasco
authors: Hospital Universitário Clementino Fraga Filho, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Simone Aranha
authors: SA
authors: Nouér
authors: Laboratório de Infecção Hospitalar, Departamento de Microbiologia Médica, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.
authors: Kátia Regina Netto
authors: KR
authors: Dos Santos
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016470:Bacteremia / Q000382:microbiology*; D003428:Cross Infection / Q000382:microbiology; D005260:Female; D006784:Hospitals, Teaching; D006801:Humans; D008297:Male; D055624:Methicillin-Resistant Staphylococcus aureus / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests; D058885:Multilocus Sequence Typing; D006435:Renal Dialysis / Q000009:adverse effects; D013203:Staphylococcal Infections / Q000382:microbiology*; D013211:Staphylococcus aureus / Q000145:classification / Q000187:drug effects / Q000235:genetics / Q000302:isolation & purification*; D020713:Vancomycin Resistance
chemical_list: D000900:Anti-Bacterial Agents