Correlating Climate Conditions With Pseudomonas aeruginosa Prevalence in Diabetic Foot Infections Within the United States.

Background: The 2023 "International Working Group on the Diabetic Foot/Infectious Disease Society of America Guidelines on the Diagnosis and Treatment of Diabetes-Related Foot Infections" (DFIs) provides recommendations for Pseudomonas coverage based on the climate region.

Methods: This was a retrospective national study of veterans between 1/1/2010 and 3/23/2024 with diabetes mellitus and a culture below the malleolus wound. Prevalence of Pseudomonas was categorized based on climate zones according to the International Energy Conservation Code. Multivariable logistic regression was used to determine odds ratios and 97.5% CIs.

Results: The prevalence of Pseudomonas significantly varied between US climates. Pseudomonas was most prevalent within the Hot Humid climate, where it was isolated in 11.6% of DFI cultures. Pseudomonas was least prevalent within the Very Cold climate, where it was isolated in 6.2% of cultures. In the multivariable logistic regression model, hot and humid climates were associated with an odds of P. aeruginosa of 1.92 (97.5% CI, 1.69-2.20), a hot, dry climate was associated with an odds of 1.65 (97.5% CI, 1.44-1.90), and a humid climate was associated with an odds of 1.65 (97.5% CI, 1.45-1.89). A lower Charlson Comorbidity Index, inpatient admission, recent antipseudomonal antibiotic use, and swabs were less likely to have Pseudomonas. Recent admission increased the odds of P. aeruginosa (odds ratio [OR], 1.34; 97.5% CI, 1.27-1.41). History of P. aeruginosa was associated with an increase in P. aeruginosa (OR, 8.90; 97.5% CI, 8.29-9.56).

Conclusions: The prevalence of DFI organisms varies within different US climates. Utilization of local climate information may allow for more accurate and targeted empiric antibiotic selection when treating DFIs.