Development of a Weighted-Incidence Syndromic Combination Antibiogram (WISCA) to guide empiric antibiotic treatment for ventilator-associated pneumonia in a Mexican tertiary care university hospital.

Summary

In 197 VAP episodes, a Bayesian hierarchical WISCA tailored to local ecology produced regimen- and ventilation-duration–specific coverage estimates. Inappropriate directed therapy, ARDS diagnosis, and higher SOFA score were independently linked to increased in-hospital mortality.

Key Findings

• Analyzed 197 VAP episodes (129 patients); predominant pathogens were Acinetobacter baumannii (n=71), Enterobacterales (n=53), and Pseudomonas aeruginosa (n=36).
• Bayesian hierarchical WISCA provided regimen- and IMV-duration–specific coverage estimates and handled uncertainty better than fixed models.
• Inappropriate directed therapy, ARDS diagnosis, and higher SOFA score were associated with increased in-hospital mortality (p<0.01).

Clinical Implications

Hospitals can adapt Bayesian WISCA to local antibiograms to improve empiric coverage and reduce inappropriate therapy; prospective implementation studies could evaluate outcome benefits.

Limitations

• Single-center retrospective design limits generalizability
• Coverage estimates are surrogate; clinical impact requires prospective validation

Future Directions

Prospective, multicenter WISCA-guided stewardship trials assessing time-to-appropriate therapy, resistance emergence, and patient-centered outcomes.