776. Relationship between Teicoplanin MICs and Treatment Failure in Teicoplanin-Treated Patients with Methicillin-Resistant Staphylococcus aureus Bacteremia
Session: Poster Abstract Session: Antimicrobials: Treatment of HAI and Resistant Infections
Friday, October 4, 2013
Room: The Moscone Center: Poster Hall C
Background: This study was conducted to determine the predictive value of teicoplanin minimal inhibitory concentrations (MICs) for treatment failure among patients with methicillin-resistant Staphylococcus aureus (MRSA) bacteremia.

Methods: Patients with bacteremia caused by MRSA between 2007 and 2012, who are ³a18 years of age, were reviewed in Aichi Medical University Hospital, Gifu University Hospital and Izumi Ladies’ Clinic. We enrolled patients with a receipt of teicoplanin therapy throughout the course. The clinical data for analysis included demographics, comorbidities, laboratory data, disease severity, and treatment outcomes. The dosage of teicoplanin administered was based on each hospital manual: a loading dose of 12 mg/kg (average 600 mg per dose) for 3 doses 12 hours apart and then every 24 hours, adjusted by the patient's renal function. Trough concentrations of teicoplanin at day 4 after initial administration were 15 to 25 mg/L in all patients. The relationship between teicoplanin MICs measured by micro-broth dilution method and treatment outcomes of MRSA bacteremia was analyzed to identify the breakpoint of teicoplanin MICs influencing treatment outcomes. Clinical resolution of bacteremia in 14 days was defined as improvement of fever status (<37.0 °C ) and improved WBC count by medical records. Eradication refers to no isolation of MRSA from the follow-up blood cultures at 7 days after cessation of teicoplanin therapy. Chi-square test or Fisher's exact test was used to test the categorical variables.

Results: Among 118 patients enrolled, 98 (83.1%) had a lower teicoplanin MIC level (1 or 2 mg/L) and 20 (16.9%) had a higher MIC level (4 or 8 mg/L) for MRSA. Teicoplanin MIC creep was also found in Japan. The lower MIC group had a higher clinical resolution rate in 14 days [19 (95.0%) vs. 55 (56.1%), p<0.01] and a lower microbiological failure rate at the end of teicoplanin treatment [1 (5.0%) vs. 35 (35.7%), p<0.05]. Results of a multivariate analysis showed that higher teicoplanin MICs (4 or 8 mg/L) was one of the independent risk factors for treatment failure.

Conclusion: Teicoplanin MIC creep was found in Japan. A higher teicoplanin MIC level may predict the treatment failure among patients with teicoplanin-treated MRSA bacteremia.

Hiroshige Mikamo, MD, PhD, Yuka Yamagishi, MD, Yukihiro Hamada, PharmD and Jun Hirai, MD, Aichi Medical University, Aichi, Japan

Disclosures:

H. Mikamo, None

Y. Yamagishi, None

Y. Hamada, None

J. Hirai, None

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