TY - JOUR
T1 - Antibiotic choice may not explain poorer outcomes in patients with Staphylococcus aureus bacteremia and high vancomycin minimum inhibitory concentrations
AU - Holmes, Natasha
AU - Turnidge, John
AU - Munckhof, Wendy
AU - Robinson, James
AU - Korman, Tony
AU - O'Sullivan, Matthew
AU - Anderson, Tara
AU - Roberts, Sally
AU - Gao, Wei
AU - Christiansen, Keryn
AU - Coombs, Geoffrey
AU - Johnson, Paul DR
AU - Howden, Benjamin
PY - 2011
Y1 - 2011
N2 - There are concerns about reduced efficacy of vancomycin in patients with Staphylococcus aureus bacteremia (SAB), especially when the minimum inhibitory concentration (MIC) nears the upper limit of the susceptible range. METHODS: We examined the relationship between antibiotic treatment, 30-day mortality, and microbiologic parameters in a large Australasian cohort of patients with SAB. RESULTS: We assessed 532 patients with SAB from 8 hospitals. All patients with methicillin-resistant S. aureus (MRSA) bacteremia were treated with vancomycin, and patients with methicillin-susceptible S. aureus (MSSA) bacteremia received either flucloxacillin or vancomycin. Increasing vancomycin MIC was associated with increased mortality in vancomycin-treated patients. However, even in patients with MSSA bacteremia treated with flucloxacillin, mortality was also higher if the vancomycin Etest MIC of their isolate was >1.5 mug/mL, compared with those with lower MIC isolates (26.8 vs 12.2 ; P <.001). After adjustment in a multivariate model, age, hospital-onset SAB and vancomycin MIC were independently associated with mortality, but methicillin resistance and antibiotic choice were not. CONCLUSIONS: We have confirmed an association between higher vancomycin MIC and increased mortality in patients with SAB, but surprisingly this relationship was not related to the antibiotic treatment received, suggesting that the use of vancomycin per se is not responsible for the poorer outcome.
AB - There are concerns about reduced efficacy of vancomycin in patients with Staphylococcus aureus bacteremia (SAB), especially when the minimum inhibitory concentration (MIC) nears the upper limit of the susceptible range. METHODS: We examined the relationship between antibiotic treatment, 30-day mortality, and microbiologic parameters in a large Australasian cohort of patients with SAB. RESULTS: We assessed 532 patients with SAB from 8 hospitals. All patients with methicillin-resistant S. aureus (MRSA) bacteremia were treated with vancomycin, and patients with methicillin-susceptible S. aureus (MSSA) bacteremia received either flucloxacillin or vancomycin. Increasing vancomycin MIC was associated with increased mortality in vancomycin-treated patients. However, even in patients with MSSA bacteremia treated with flucloxacillin, mortality was also higher if the vancomycin Etest MIC of their isolate was >1.5 mug/mL, compared with those with lower MIC isolates (26.8 vs 12.2 ; P <.001). After adjustment in a multivariate model, age, hospital-onset SAB and vancomycin MIC were independently associated with mortality, but methicillin resistance and antibiotic choice were not. CONCLUSIONS: We have confirmed an association between higher vancomycin MIC and increased mortality in patients with SAB, but surprisingly this relationship was not related to the antibiotic treatment received, suggesting that the use of vancomycin per se is not responsible for the poorer outcome.
UR - http://jid.oxfordjournals.org/content/204/3/340.full.pdf+html
U2 - 10.1093/infdis/jir270
DO - 10.1093/infdis/jir270
M3 - Article
VL - 204
SP - 340
EP - 347
JO - The Journal of Infectious Diseases
JF - The Journal of Infectious Diseases
SN - 0022-1899
IS - 3
ER -