CHARACTERIZATION OF BACTEREMIC AND NON-BACTEREMIC SYNDROMES OF INVASIVE ESCHERICHIA COLI DISEASE AMONG HOSPITALIZED ADULTS AGED ≥60 YEARS: FINDINGS FROM A PROSPECTIVE, MULTINATIONAL, OBSERVATIONAL STUDY (EXPECT-2)

Intro: Published data is limited in describing clinical features and disease burden of invasive Escherichia coli disease (IED). This study characterized bacteremic and non-bacteremic IED in relation to clinical features and multidrug resistance (MDR) of causative E. coli isolates. Methods: EXPECT-2 (NCT04117113) was a multinational, hospital-based, observational study that prospectively enrolled IED patients aged ≥60 years between October 2019 and January 2021. IED was defined by a positive E. coli culture from blood (bacteremic IED), a sterile body site or urine (non-bacteremic IED) in the presence of requisite criteria of Systemic Inflammatory Response Syndrome (SIRS), Sequential Organ Failure Assessment (SOFA), or quick SOFA (qSOFA). In-hospital mortality and IED-related medical encounters were assessed through 28 days following IED diagnosis. MDR was defined as acquired non-susceptibility to ≥1 antibiotic in ≥3 antimicrobial classes. Findings: The full analysis set included 193 bacteremic (80.4%) and 47 non- bacteremic (19.6%) patients. Patient demographics were balanced between bacteremic and non-bacteremic IED. The rates of patients with ≥2 SIRS criteria were comparable between bacteremic (64.8%) and non-bacteremic IED (70.2%). The rates of patients with the ≥2-point change in total SOFA score were comparable between bacteremic (62.2%) and non-bacteremic IED (53.2%). The rates of sepsis and septic shock were 75.0% and 11.4%, respectively, for bacteremic, and 83.3% and 7.1%, respectively, for non-bacteremic IED. The most common IED-related medical encounter was the emergency room both in patients with bacteremic (31.5%, [41/130]) and non-bacteremic IED (35.9%, [14/39]). Of 11 patients who died, 6 (54.5%) had bacteremic IED. Of 294 E. coli isolates with antimicrobial susceptibility testing collected from 238 patients, MDR rates were 34.7% (87/251) for bacteremic and 37.2% (16/43) for non-bacteremic isolates. Conclusion: IED manifested as severe infection, with approximately one-third of E. coli isolates displaying MDR. Bacteremic and non-bacteremic IED were characterized by similar clinical features and MDR phenotypes.