Epidemiologic Risk Factors of Antimicrobial Resistance in Patients with Septic Shock Admitted to North American Critical Care Units: A Retrospective Study

  • Author / Creator
    Hewer, Tayne
  • INTRODUCTION: Antibiotic resistance is a serious global threat resulting in a significant clinical and economic burden. The cost of caring for patients with resistant infections is high ($6,000-$30,000 USD 2008). The examination of resistance between different epidemiological groups is required to identify patient populations admitted to an intensive care unit (ICU) who may be more susceptible to life-threatening infections caused by resistant pathogens; it should also allow for preventative and treatment strategies aimed at reducing resistance and related complications, while improving outcomes, reducing ICU length of stay and corresponding health care costs.
    PURPOSE: The specific aim of this retrospective study was to examine the frequency of resistant organisms among different epidemiological sub-groups of patients admitted to the ICU within the Cooperative Anti-microbial Therapy of Septic Shock (CATSS) Database with a diagnosis of septic shock and to determine independent predictors of the presence of antibiotic resistant organisms at the time of septic shock within this same population. The secondary specific aim was to describe the effect of the presence of antibiotic resistance on ICU and hospital mortality.
    METHODS: We conducted a retrospective review of critically ill patients with septic shock within the CATSS Database between 1996 and 2012 (n=10,800). The presence of resistant organisms was assessed in relation to age, APACHE II, type and number of comorbidities, ICU admission source, and acquisition of infection (community vs nosocomial). Multivariable logistic regression analysis was utilized to determine the independent predictors of presenting with antibiotic resistant organisms at the time of septic shock diagnosis. Individual multivariable logistic regression analysis models were used to determine independent predictors of ICU and hospital mortality after adjustment for the presence of resistant organisms.
    RESULTS: Increasing age (OR 1.004 95% CI 1.001,1.007), liver failure (OR 1.27, 95% CI 1.028,1.463), ventilator dependence (OR 2.088, 95% CI 1.159,3.761), insulin dependent diabetes mellitus (OR 1.215, 95% CI 1.036,1.424), elective surgery (OR 1.332, 95% CI 1.166,1.521), emergent surgery (OR 1.244, 95% CI 1.045,1.482), neuromuscular disease (OR 1.540, 95% CI 1.153,2.057) and nosocomial acquired infection (OR 1.699 95% CI 1.517,1.904) were independent predictors of an increased odds of the presence of any antibiotic resistant organism at the time of septic shock diagnosis. The presence of leukemia (OR 0.797 95% CI 0.636, 0.998) and history of hypertension (OR 0.863, 95% CI 0.777, 0.958) were independent predictors of a reduced odds of the presence of any resistant organism. The presence of a resistant organism was significantly associated with an increased hospital but not ICU mortality in the univaraible model (OR 1.214 95% CI 1.118, 1.318) but did not show a significant association when adjusted for relevant covariates.

    CONCLUSION: In this retrospective study of septic patients admitted to North American intensive care units, age, liver failure, ventilator dependence, insulin dependent diabetes mellitus, neuromuscular disease and nosocomial acquired infection were patient specific predictors of the presence of antibiotic resistance organisms at the time of diagnosis of septic shock. Both elective and emergent surgery (vs medical diagnoses) was also associated with an increased odds for the presence of an antibiotic resistant organism. However, leukemia and history of hypertension were associated with a lower odds of the presence of antibiotic resistance. The presence of a resistant organism was associated with increased hospital but not ICU mortality in crude associations. We did not show significant association between resistance and mortality after adjustment for relevant confounders. Further research should focus efforts on these sub-populations for prevention of hospital acquired antibiotic resistance.

  • Subjects / Keywords
  • Graduation date
    Fall 2018
  • Type of Item
  • Degree
    Master of Science
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