Incidence and characteristics of vancomycin nonsusceptible strains of methicillin-resistant Staphylococcus aureus at Hershey Medical Center.
All 982 methicillin-resistant Staphylococcus aureus strains collected from August 2006 to December 2007 were tested for vancomycin susceptibility by using 3-microg/ml vancomycin brain heart infusion screening plates, a vancomycin Etest, and a vancomycin/teicoplanin macro Etest. Three vancomycin-intermediate Staphylococcus aureus (VISA) (0.3%) and two heterogeneous VISA (0.2%) isolates were identified. The screening method yielded 895 cases of < or =1 colony and 87 positive results (with growth of >1 colony after 48 h); further Etests showed 82/87 isolates with growth on screening plates to be false positive. Repeat testing showed a false-positivity rate of only 15 of the original 87 isolates by plate screening.
Department of Pathology H160, Hershey Medical Center, P.O. Box 850, Hershey, PA 17033. pappelbaum@psu.edu.
Klaudia
K
Kosowska-Shick
Lois M
LM
Ednie
Pamela
P
McGhee
Kathy
K
Smith
Cynthia D
CD
Todd
Amanda
A
Wehler
Peter C
PC
Appelbaum
D000046:Academic Medical Centers; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D005189:False Positive Reactions; D006801:Humans; D015994:Incidence; D055624:Methicillin-Resistant Staphylococcus aureus / Q000145:classification / Q000187:drug effects* / Q000302:isolation & purification; D008826:Microbial Sensitivity Tests / Q000379:methods; D010414:Pennsylvania / Q000453:epidemiology; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology; D014640:Vancomycin / Q000494:pharmacology; D020713:Vancomycin Resistance
D000900:Anti-Bacterial Agents; D014640:Vancomycin