Alos JI

Bland CM

Chan S

Clinical and Laboratory Standards Institute

Di Pentima MC

Frymoyer A

Giuliano C

Holmes NE

Jimenez-Truque N

Kaplan SL

Kish MA

Purcell K

Richards MJ

Sievert DM

Steinkraus G

Stevens DL

Ward PB

ABSTRACT
          
            We evaluated the evolution of vancomycin MICs for
            Staphylococcus aureus
            and their relationship with vancomycin use among hospitalized children.
            S. aureus
            isolates recovered from sterile sites were prospectively tested for vancomycin susceptibility using the Etest between 1 April 2000 and 31 March 2008. Vancomycin MICs were grouped into three categories: ≤1, 1.5, and 2 μg/ml. The association between vancomycin MICs and aggregate vancomycin use and individual patient vancomycin exposure 6 months prior to the documented infection was assessed. The geometric mean values for vancomycin MICs for
            S. aureus
            fluctuated over time without a significant trend (
            P
            = 0.146). Of the 436 patients included in the study, 363 (83%) had methicillin-susceptible
            S. aureus
            (MSSA) and 73 (17%) had methicillin-resistant
            S. aureus
            (MRSA) infections. The rate of isolates with a vancomycin MIC of 2 μg/ml increased from 4% (2 of 46) in 2000 to 2001 to 24% (11 of 46) in 2007 to 2008, despite a decrease in vancomycin use (
            r
            = −0.11;
            P
            = 0.825). The percentage of isolates with a vancomycin MIC of 2 μg/ml was higher for MRSA (15%; 11 of 73) than for MSSA strains (5.2%; 19 of 363) (χ
            2
            = 9.2;
            P
            = 0.01). Individual patient vancomycin exposure was not associated with a higher vancomycin MIC. In the unadjusted model, in which we compared patients with
            S. aureus
            infections with MICs of ≤1 μg/ml, the odds ratios of exposure rates for patients with isolates with MICs of 1.5 μg/ml and 2 μg/ml were 1.02 (
            P
            = 0.929) and 1.13 (
            P
            = 0.767), respectively. In our experience, the geometric means of vancomycin MICs from
            S. aureus
            isolates recovered from hospitalized children oscillated over time and were not associated with previous individual patient vancomycin exposure or aggregate vancomycin use.
          </jats:p

Lucia Rose

Shannon Chan

Jobayer Hossain

M. Cecilia Di Pentima

Crossref

Journal of Clinical Microbiology

Effects of Aggregate and Individual Antibiotic Exposure on Vancomycin MICs for Staphylococcus aureus Isolates Recovered from Pediatric Patients

Effects of Aggregate and Individual Antibiotic Exposure on Vancomycin MICs for Staphylococcus aureus Isolates Recovered from Pediatric Patients

Abstract

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