Study ties prevalence of drug-resistant organisms to socioeconomic conditions

A study in Texas found higher rates of antimicrobial-resistant (AMR) organisms in areas with higher levels of economic deprivation, researchers reported today in Clinical Infectious Diseases.

Using electronic health records from two large healthcare systems in the Dallas-Fort Worth metropolitan area, a team led by researchers from the University of Texas Southwestern Medical Center collected select patient bacterial culture results from 2015 to 2020. They chose five AMR organisms to represent potential community- and healthcare-associated acquisition, used residential addresses to geocode cultures and link them to socioeconomic index values, and identified geographic clusters of high and low AMR organism prevalence.

Among the 43,677 unique cultures collected, 43.5% were identified as methicillin-resistant Staphylococcus aureus (MRSA), 31% as extended-spectrum beta-lactamase (ESBL)–producing organisms, 11.3% as carbapenem-resistant Enterobacterales, 8.2% as vancomycin-resistant Enterococcus, and 5.9% as AmpC beta-lactamase producers. Significant clusters of all five organisms were found in areas with high levels of economic deprivation, as measured by the area deprivation index (ADI), and there was significant spatial autocorrelation between ADI and AMR prevalence.

The strongest correlation was observed for MRSA and AmpC, with 14% and 13%, respectively, of the variability in prevalence rates attributed to their relationship with the ADI values of the neighboring locations.

Tailored interventions may be needed

The study authors say several factors could explain why AMR organisms are more prevalent in areas with greater socioeconomic disparities. For example, people in areas with higher ADI may have poorer sanitation due to utility disruptions or poor plumbing and therefore be more likely to be exposed to bacteria, or may live in overcrowded settings that can contribute to the spread of infection. The practice of sharing “leftover” antibiotics with friends and family could also select for resistant organisms.

While further research is needed to delineate the relationship, they say the findings highlight the importance of addressing these disparities.

“This finding that ADI is associated with higher prevalence of AMR supports the need for tailored, local interventions for small neighborhoods including social programs that increase access to health insurance, along with public health campaigns discussing proper hygiene techniques to prevent the spread of disease within a household,” they wrote.