Spatial, Ecologic, and Clinical Epidemiology of Community-Onset, Ceftriaxone-Resistant Enterobacteriaceae, Cook County, Illinois, USA

We performed a spatial and mixed ecologic study of community-onset Enterobacteriaceae isolates collected from a public healthcare system in Cook County, Illinois, USA. Individual-level data were collected from the electronic medical record and census tract–level data from the US Census Bureau. Associations between individual- and population-level characteristics and presence of ceftriaxone resistance were determined by logistic regression analysis. Spatial analysis confirmed nonrandom distribution of ceftriaxone resistance across census tracts, which was associated with higher percentages of Hispanic, foreign-born, and uninsured residents. Individual-level analysis showed that ceftriaxone resistance was associated with male sex, an age range of 35–85 years, race or ethnicity other than non-Hispanic Black, inpatient encounter, and percentage of foreign-born residents in the census tract of isolate provenance. Our findings suggest that the likelihood of community-onset ceftriaxone resistance in Enterobacteriaceae is influenced by geographic and population-level variables. The development of effective mitigation strategies might depend on better accounting for these factors.