International journal of antimicrobial agents
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Int. J. Antimicrob. Agents · Dec 2009
Differences in phenotypic and genotypic characteristics among imipenem-non-susceptible Acinetobacter isolates belonging to different genomic species in Taiwan.
In this study, we investigated the distribution of genes encoding various carbapenemases as well as their association with carbapenem resistance in clinical isolates of Acinetobacter genomic species from Taiwan. A total of 129 imipenem-non-susceptible and 79 imipenem-susceptible isolates were examined, of which 185 (88.9%) were Acinetobacter baumannii. Among the 185 A. baumannii isolates, imipenem non-susceptibility was more common in isolates with ISAba1-bla(OXA-51-like) (72/75; 96%), bla(OXA-58-like) (33/33; 100%) or bla(OXA-24-like) (7/7; 100%) than in isolates with only bla(OXA-51-like) (4/72; 5.6%). ⋯ Among the 23 isolates of non-baumannii Acinetobacter spp., bla(OXA-58-like) and MBL genes were widely disseminated in the imipenem-resistant isolates, and isolates with bla(OXA-58-like) and MBL genes had higher imipenem minimum inhibitory concentrations than those with bla(OXA-58-like) alone. Although the rate of non-susceptibility to colistin was 26.7% among the imipenem-non-susceptible isolates of non-baumanniiAcinetobacter, 93.3% and 100% were susceptible to ciprofloxacin and tigecycline, respectively. In conclusion, different isolates of imipenem-non-susceptible A. baumannii and non-baumanniiAcinetobacter contained different carbapenemases and had different antimicrobial susceptibilities.
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Int. J. Antimicrob. Agents · Dec 2009
Nephrotoxicity of continuous versus intermittent infusion of vancomycin in outpatient parenteral antimicrobial therapy.
Intravenous (i.v.) vancomycin is increasingly used as outpatient parenteral antimicrobial therapy (OPAT). Despite the potential advantages of administration by continuous infusion (CI) compared with intermittent infusion (II), the relative nephrotoxicity of these two modes of delivery has not been well established. We compared the rate of nephrotoxicity of vancomycin given by CI and II. ⋯ Both in unadjusted and adjusted analyses, vancomycin CI was associated with a slower onset of nephrotoxicity but not a lower prevalence of nephrotoxicity. Both groups received a similar cumulative vancomycin dose. In adult OPAT patients with normal renal function, vancomycin CI was associated with a slower onset of nephrotoxicity.
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Int. J. Antimicrob. Agents · Dec 2009
Impact of early appropriate antimicrobial therapy on survival in Acinetobacter baumannii bloodstream infections.
The impact of appropriate empirical antimicrobial therapy for Acinetobacter baumannii bacteraemia on patient outcomes has not been clearly established. We assessed predictors of 30-day mortality and the effect of inappropriate empirical antimicrobial treatment on mortality among patients with A. baumannii bacteraemia between July 2005 and June 2008. Initial empirical antimicrobial therapy was considered to be appropriate if the initial antibiotics that were administered within 48 h after the acquisition of a blood culture sample included at least one antibiotic that was active in vitro and when the dosage and route of administration were in accordance with current medical standards. ⋯ Thus, a 25.5% reduction in the overall crude mortality rate was associated with adequate early empirical antimicrobial therapy. Multivariate analysis using a Cox regression model showed that significant independent risk factors for mortality were delayed appropriate treatment [hazard ratio (HR)=2.4, 95% confidence interval (CI) 1.3-4.2; P=0.004], development of septic shock (HR=2.6, 95% CI 1.4-4.8; P=0.004), age>65 years (HR=2.1, 95% CI 1.2-3.7; P=0.007) and mechanical ventilation (HR=3.3, 95% CI 1.5-7.4; P=0.003). It is concluded that a delay in receiving appropriate antimicrobial therapy had an adverse influence on clinical outcome in patients with A. baumannii bacteraemia.