Direct Hospitalization Costs Associated with Resistant and Susceptible Salmonella and Shigella Infections in the United States, 2012–2019

Antimicrobial-resistant enteric infections may be difficult to treat, associated with severe outcomes, and costly. To determine if resistant enteric infections are more costly, we described direct hospitalization costs for hospital admissions for typhoid fever, salmonellosis, and shigellosis infections by resistance status. We included all inpatient admissions with culture-confirmed infections from approximately 300 hospitals in the Premier Healthcare database during 2012–2019. We classified typhoid fever, salmonellosis, and shigellosis infections as clinically resistant if laboratory testing found resistance to ≥1 antibiotic class recommended for treatment. We examined patient demographic characteristics and underlying chronic conditions. We used the Wilcoxon rank sum test to assess the difference in median hospitalization cost for each patient admission by resistance status. We estimated adjusted cost and length of stay (LOS) using multivariable linear regression, adjusting for host and health care provider characteristics. Among 67 inpatient admissions for typhoid fever, 3421 for salmonellosis, and 619 for shigellosis, 33% of typhoid fever, 13% of salmonellosis, and 82% of shigellosis infections were clinically resistant. The unadjusted median costs for resistant salmonellosis were higher than susceptible infection-related costs ($7,753 vs. $6,909, p = 0.002). The unadjusted costs for resistant versus susceptible typhoid fever ($13,709 vs. $9,254, p = 0.111) and shigellosis were similar ($5,365 vs. $5,777, p = 0.167). For all three pathogens, the adjusted mean hospitalization costs were not statistically different for resistant and susceptible infections. Adjusted mean LOS was significantly longer for resistant typhoid fever compared with susceptible infections (6.50 days vs. 4.35 days, p = 0.001). Although adjusted cost differences for resistant infections were not significant, we observed differences by host factors including age and comorbidities, suggesting patient demographic characteristics for resistant infections are impactful on cost. These findings support the premise that public health interventions to limit the spread of resistant infections, particularly among individuals at higher risk for severe illness, could reduce hospitalization costs.