Heterogeneous resistance to vancomycin and teicoplanin among Staphylococcus spp. isolated from bacteremia

Abstract

This study evaluated the BHIA screening method with 4 or 6 μg/mL of vancomycin to detect glycopeptides heteroresistant staphylococci strains isolated from bacteremia. A total of 213 staphylococci strains were isolated from 106 patients between October/2001 and November/2002 ina tertiary hospital in Rio de Janeiro city. Fifty-seven (53.8%) patients presented Staphylococcus aureus, while coagulase-negative staphylococci (CNS) were isolated from 49 (46.2%). Resistance rates for oxacillin of 26.3% and 81.6% were found for the staphylococci isolates, respectively. Thirteen CNS isolated from nine (8.5%) patients grew on agar screening with 4 μg/mL of vancomycin and showed, heterogeneous profiles of resistance for vancomycin and teicoplanin by the population analysis profile method. Only 30.8% of them grew at the concentration 6 μ/mL. Bacterial infection and use of antimicrobial therapy were common among these patients. Alert about the emergence of oxacillin-resistant staphylococci presenting heteroresistance to glycopeptides; is important in order to achieve judicious use of antimicrobials. Vanopmycin agar screening test could help to confirm the presence of these isolates in hospitals. © 2007 by The Brazilian Journal of Infectious Diseases and Contexto Publishing. All rights reserved.