Relationship Between Multidrug-Resistant Enterobacterales and Obesity in Older Adults

Purpose: The objective of our study was to determine if obesity is associated with the presence of multidrug-resistant (MDR) bacteria among Enterobacterales. Patients and Methods: This two-center cohort study included adult hospitalized patients with at least one specimen sampled from any site for bacterial culture yielding an Enterobacterales bacterial species from November 2016 to May 2017. Study groups were stratified by obesity status based on body mass index <30 kg/m2 (non-obese) and >30 kg/m2 (obese). The primary outcome was the presence of gram-negative MDR bacteria defined as presumptive extendedspectrum beta-lactamase (ESBL)-producing Enterobacterales (ceftriaxone resistance) or carbapenem-resistant Enterobacterales (CRE). A multivariable logistic regression model was fit to estimate the adjusted odds ratio while controlling for potential confounders. Results: A total of 366 patients, 238 non-obese and 128 obese, were included. The most common gram-negative bacterial species identified was Escherichia coli (64.2%). There was a higher proportion of gram-negative MDR bacteria in obese versus non-obese patients (18.8 versus 11.3%, P=0.057). Obesity was independently associated with gram-negative MDR bacteria after controlling for confounders (adjusted odds ratio, 1.92; 95% CI 1.03-3.60). The association did not significantly vary by diabetes status (interaction term P=0.792). Conclusion: Among older adult hospitalized patients, obesity was independently associated with the presence of a gram-negative MDR bacteria (presumptive ESBL or CRE) in a culture.