Introducing the Escalation Antibiogram: A Simple Tool to Inform Changes in Empiric Antimicrobials in the...

Area of Science:

• Infectious Diseases
• Clinical Microbiology
• Antimicrobial Stewardship

Background:

• Hospital antibiograms are crucial for initial antibiotic selection but lack guidance for nonresponding patients.
• Escalation of antibiotic therapy requires specific data to ensure effective treatment adjustments.

Purpose of the Study:

• To introduce and evaluate the concept of an "escalation antibiogram" for guiding treatment changes in gram-negative bacteremia.
• To assess the utility of escalation antibiograms in identifying optimal antibiotic choices for nonresponding patients.

Main Methods:

• Generated escalation antibiograms for 12 common agents using gram-negative bacteremia data from 6 hospitals (2017-2020).
• Calculated the likelihood of susceptibility to alternative agents among organisms resistant to a primary agent.
• Subgroup analyses examined trends across years, hospitals, onset types, and pathogen categories.

Main Results:

• Ampicillin had 31.8% coverage, while carbapenems like meropenem (98.2%) and amikacin (97.5%) showed high coverage.
• Escalation antibiograms highlighted significant differences in susceptibility; e.g., ceftriaxone-resistant isolates showed lower susceptibility to piperacillin-tazobactam (21.2%) than other agents.
• Trimethoprim-sulfamethoxazole was a key agent for escalation from meropenem and amikacin resistance.

Conclusions:

• Escalation antibiograms provide valuable data for optimizing empiric antibiotic treatment changes in nonresponding patients.
• These tools can prevent common, potentially ineffective treatment escalations, such as from ceftriaxone to piperacillin-tazobactam.