Clinical and microbiological factors associated with early patient mortality from methicillin-resistant Staphylococcus aureus bacteremia

• Main Authors: Tark Kim, Yong Pil Chong, Ki-Ho Park, Kyung Mi Bang, Su-Jin Park, Sung-Han Kim, Jin-Yong Jeong, Sang-Oh Lee, Sang-Ho Choi, Jun Hee Woo, Yang Soo Kim
• Format: Article
• Language: English
• Published: The Korean Association of Internal Medicine 2019-01-01
• Series: The Korean Journal of Internal Medicine
• Subjects: methicillin-resistant staphylococcus aureus; bacteremia; risk factors; mortality
• Online Access: http://www.kjim.org/upload/pdf/kjim-2016-351.pdf

Background/Aims Methicillin-resistant Staphylococcus aureus bacteremia (MRSAB) is a major bloodstream infection with a high mortality rate. Identification of factors associated with early mortality in MRSAB patients would be useful for predicting prognosis and developing new therapeutic options. Methods A prospective cohort of MRSAB patients was examined between August 2008 and June 2011. Early and late mortality was defined as death within 2 and 28 days of blood culture, respectively. The clinical and microbiological characteristics in the early and late mortality and survival groups were compared. Risk factors associated with severe sepsis or septic shock were also investigated. Results A total of 385 adult MRSAB patients whose S. aureus isolates were available were enrolled; of these patients, 25 patients (6.5%) and 50 (13%) died early and late, respectively. Compared with both the late-mortality group and the survival group, severe sepsis or septic shock was a statistically significant independent risk factor associated with early mortality. Rapidly or ultimately fatal McCabe and Jackson classification (adjusted odds ratio [aOR], 1.94; 95% confidence interval [CI], 1.25 to 3.02) and pneumonia (aOR, 2.04; 95% CI, 1.03 to 4.02) were independently associated with severe sepsis or septic shock. A vancomycin minimum inhibitory concentration (MIC) ≥ 1.5 μg/mL was associated with a reduced incidence of severe sepsis or septic shock (aOR, 0.53; 95% CI, 0.34 to 0.84). Conclusions Severity of illness seems to be the most important risk factor associated with early mortality in MRSAB. Although vancomycin MIC was not independently associated with early mortality, reduced vancomycin susceptibility appears to be linked to reduced disease severity.