Prognosis of patients with methicillin-resistant Staphylococcus aureus bloodstream infection treated with teicoplanin: a retrospective cohort study investigating effect of teicoplanin minimum inhibitory concentrations.

BACKGROUND: The present study was designed to investigate whether teicoplanin minimum inhibitory concentrations (MICs) of methicillin-resistant Staphylococcus aureus (MRSA) isolates play a role in the prognosis of patient with teicoplanin-treated MRSA bloodstream infection (BSI). METHODS: Between 1 January 2006 and 31 December 2009, adult patients with teicoplanin-treated MRSA BSI in two Taiwan medical centers were retrospectively enrolled. Their blood MRSA isolates were submitted for determination of MICs to various antibiotics and multi-locus sequence types. All-cause mortalities on Days 14 and 30, as well as clinical response at the end of teicoplanin therapy were treated as endpoints. RESULTS: Two hundred seventy adult patients were enrolled and 210 blood MRSA isolates were available. Independent risk factors for un-favorable outcome at the end of teicoplanin therapy included septic shock (p < 0.0001) and an elevated C-reactive protein level (p = 0.0064). The independent risk factors for all-cause Day 14 mortality (13.0%) included the presence of auto-immune diseases (p = 0.0235), septic shock (p = 0.0253) and thrombocytopenia (p = 0.0018). The independent risk factors for all-cause Day 30 mortality (26.3%) included age (p = 0.0102), septic shock (p < 0.0001) and thrombocytopenia (p = 0.0059). CONCLUSIONS: The current study didn't find a significant role for teicoplanin MICs in the prognosis of adult patients with teicoplanin-treated MRSA BSI.

In vitro activity of linezolid, tigecycline, and daptomycin on methicillin-resistant Staphylococcus aureus blood isolates from adult patients, 2006-2008: stratified analysis by vancomycin MIC.

BACKGROUND: The recent molecular epidemiological studies concerning epidemiological studies concerning methicillin-resistant Staphylococcus aureus (MRSA) blood isolates from adult patients and susceptibilities of MRSA isolates with high vancomycin minimum inhibitory concentrations (MICs) (≥2 mg/L) to linezolid, tigecycline, and daptomycin in Taiwan remain limited. The objectives of the study were (1) to better understand the change of molecular epidemiology of MRSA blood isolates and (2) to evaluate the in vitro activity of new anti-Gram-positive agents, including linezolid, tigecycline, and daptomycin. METHODS: A total of 470 nonduplicate MRSA blood isolates from adult patients (older than 18 years) were collected from January 2006 to December 2008. The MICs of these isolates to various antibiotics were determined. Multilocus sequence typing was also performed in all isolates. RESULTS: Three sequence types (STs) constitute most (92.1%) of these 470 MRSA isolates: ST239 (53.2%), ST59 (23.2%), and ST5 (15.7%). Throughout the 3-year study, the ST239 strain remained predominant but with a significant trend of declining annually (p=0.03). In contrast, the proportion of isolates of ST59 increased, although the increment was insignificant (p=0.14). The proportion of MRSA isolates with a vancomycin MIC of 2 mg/L was 17.2%. All of these isolates with a vancomycin MIC of 2 mg/L were susceptible to linezolid and tigecycline, whereas most of them (98.8%) were susceptible to daptomycin. CONCLUSIONS: ST239 remained predominant during the 3-year period but with a significant trend of declining. Moreover, linezolid, tigecycline, and daptomycin remained highly active against MRSA blood isolates, even with a vancomycin MIC of 2 mg/L.

Risk factors for mortality of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection: with investigation of the potential role of community-associated MRSA strains.

OBJECTIVES: The difference in the outcomes of nosocomial bloodstream infection (BSI) caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) strains and healthcare-associated MRSA (HA-MRSA) strains remains unclear. METHODS: From January 1, 2006 to December 31, 2008, all adult patients hospitalized at National Taiwan University Hospital with nosocomial MRSA BSI were analyzed. Available MRSA isolates were submitted for subsequent microbiologic studies to determine whether they belonged to CA-MRSA strains. RESULTS: In total, 308 patients were enrolled and 253 MRSA isolates were available. Forty-seven isolates belonged to CA-MRSA strains. The all-cause mortality rates on Day 14 and Day 30 were 19.8% and 30.5%, respectively, and were not different between those caused by CA-MRSA and HA-MRSA strains. The independent risk factors for Day 14 mortality were septic shock, thrombocytopenia, and an inadequate serum trough level of vancomycin (p = <0.0001, 0.0003, and 0.0381, respectively). Those for Day 30 mortality were septic shock, anemia, thrombocytopenia, presence of underlying malignancies, and MRSA isolates with a vancomycin minimum inhibitory concentration of 2 mg/L (p = <0.0001, 0.0425, 0.0007, 0.0098, and 0.0012, respectively). CONCLUSIONS: The mortality rates of nosocomial MRSA BSI were not different between that caused by CA-MRSA and HA-MRSA strains.