Category: Professional Posters
Purpose: Infections with multidrug-resistant organisms (MDROs) have been associated with increased lengths of stay, costs, morbidity, and mortality. Because risk factors for development of an MDRO infection differ by facility, the CDC recommends monitoring of institution-specific trends of MDRO infections to quantify risk factors for the development of such infections. The objectives of this study were to determine the total incidence of MDRO infections in the adult inpatient population at San Joaquin General Hospital and to identify risk factors for the development of MDRO infections to direct antimicrobial stewardship efforts.
Methods: This was a retrospective, observational, chart review study of data collected from January 1, 2015 to December 31, 2018. A total of 200 MDRO isolates were randomly selected for chart review, comprised of 25 Gram-positive and 25 Gram-negative isolates from each year. Patients age 18 or older and who grew an MDRO that met laboratory-defined criteria were included in the study. Patients under the age of 18 or those who had positive cultures while not admitted as inpatients were excluded. The primary endpoint was to assess the overall prevalence of MDRO infections over the past four years. The data was normalized to reflect the incidence based on 100 patient admissions and compared between the four years. Secondary endpoints included the prevalence of risk factors (coexisting infection, prior antibiotic exposure, previous ICU admission, recent surgery, previous hospitalization, residence in a nursing home or long-term care facility, history of cancer or immunodeficiency, central lines or other hemodialysis access sites, and indwelling Foley or suprapubic catheter) and the burden of infection (all-cause mortality and length of stay). Subgroup analysis evaluated differences in risk factors and outcomes based on the culture source.
Results: A total of 1990 MDRO isolates were reviewed, 1008 of which were excluded because they were duplicate cultures or were drawn from patients in the emergency room or outpatient clinics. Overall, there were 982 MDRO isolates, including 566 Gram-positive and 416 Gram-negative organisms. The total incidence of MDRO isolates normalized per 100 patient admissions ranged from 2.63% to 2.77% across the four year period. The risk factors of highest prevalence were recent surgery (66%), prior antibiotic exposure (52.5%), and presence of a urinary catheter (51%). The risk factor of lowest prevalence was history of cancer (8.5%). There were 5 deaths in the Gram-positive group and 12 deaths in the Gram-negative group. The average length of stay was longer for Gram-negative infection (17.9 days versus 13.7 days). Recent surgery was the most common risk factor associated with isolation of a Gram-positive or Gram-negative MDRO from blood, wound, and biopsy cultures.
Conclusion: The incidence of MDRO infection was similar from 2015 to 2018. There was a trend towards higher mortality and longer average length of stay in patients with Gram-negative MDRO infections. Recent surgery, prior antibiotic exposure, and presence of a urinary catheter were consistently identified as the top risk factors associated with the development MDRO infection.