Frequency of reduced vancomycin susceptibility and heterogeneous subpopulation in persistent or recurrent...

Vancomycin susceptibility was checked in isolates from initial and final blood samples obtained from 22 patients with persistent or recurrent methicillin-resistant Staphylococcus aureus bacteremia. The minimum inhibitory concentration of vancomycin was determined using Etest and found to have increased in 2 pairs of isolates, and results of screening in 4 mu g vancomycin and a modified population analysis profile suggested heteroresistance in 3 isolates (13.6%). Heteroresistance is not a common cause of persistent or recurrent bacteremia.