Multi-drug resistant (MDR) and more specifically, extended-spectrum beta-lactamase-producing Enterobacterales (ESBL Ent) have emerged as a serious public health threat. The incidence of ESBL Ent infections has increased dramatically during the past decade, now reaching nearly 200,000 infections and over 9,000 deaths per year in the US.Although ESBL Ent were once largely healthcare-associated pathogens, in the past two decades most ESBL Ent infections have been caused by clinically and genetically distinct strains that have emerged in community settings.Invasive infections caused by these community-acquired (CA) ESBL Ent strains are increasingly being reported in young children and individuals without significant healthcare exposures.Importantly, these strains are resistant to antibiotics that are uncommonly used in children, and thus overuse is unlikely to be driving this resistance.
The factors promoting MDR Ent (e.g. ESBL and FQR Ent) acquisition and infection in the community are largely unknown. However, in households with an adult member known to have acquired ESBL Ent from healthcare exposures, transmission incidence has been described to be as high as 67%. Furthermore, in a multicenter investigation of multidrug-resistant (MDR; primarily ESBL) Ent in Chicago children, we found that MDR Ent acquisition reflected geographic clustering and lacked association with the factors driving primary ESBL and FQR Ent acquisition in adults (e.g., antibiotic and healthcare exposures). We also found that compared to antibiotic-sensitive Ent infections in children, CTX-M-9 type ESBL Ent infections were nearly 5 times more likely to be community-acquired. To devise strategies to prevent CA MDR Ent infections, we must first understand key reservoirs for acquisition, including sources of transmission outside of healthcare settings (e.g., community), the role of the built environment in pathogen transmission, and epidemiologic factors associated with CA MDR Ent acquisition, transmission, and infection.
The influence of population-level variables (such as demographic or economic indices) on CA-MDR Ent distribution across communities is unknown. The influence of dwelling in areas with high CA-MDR Ent burden on individual risk for CA-MDR Ent colonization or infection is also unknown. Identifying areas with high disease burden can help target large-scale interventions. Identifying whether residence in specific census tract is a significant risk factor for CA-MDR Ent disease can help guide empiric antimicrobial treatment guidelines.