Table 1.

Advantages and disadvantages of traditional, combination, syndromic, and weighted incidence syndromic combination antibiograms (WISCA).

	Advantages	Disadvantages
Traditional antibiograms Example: Susceptibility of Pseudomonas aeruginosa to piperacillin/tazobactam (TZP)	• Readily available • Easily understood by clinicians • Completed at least annually • Ability to assist in empiric antibiotic therapy recommendations • Easily incorporated into disease- state treatment guidelines	• Require a minimum of 30 pathogens/year • Revision of antibiotic breakpoints may not be included • Lack of inclusion of infection source and/or hospital location • Binary measure of susceptibility (susceptible versus non-susceptible/resistant) • Lack of incorporation of patient variables (age, gender, and comorbidities) • Limited correlation with clinical and microbiological outcomes
Combination antibiograms Example: Additional susceptibility of Pseudomonas aeruginosa to TZP + tobramycin versus TZP alone	• Ability to evaluate coverage of multiple antibiotics • Ease of completion • Useful in determining combined empiric antibiotic regimens for multidrug-resistant pathogens	• Less easily understood by prescribers • Typically requires manual completion • Lack of CLSI guidance for completion • Require a minimum of 30 pathogens/year • Antibiotic susceptibilities derived from percentages not in vitro synergy • Lack of incorporation of patient variables (age, gender, and comorbidities) • Limited correlation with clinical and microbiological outcomes
Syndromic antibiograms Example: Susceptibility of Pseudomonas aeruginosa to TZP among respiratory specimens (obtained among ICU patients only)	• Increased likelihood of providing effective empiric antibiotic therapy for a specific infectious syndrome • May be further stratified based on hospital location • Provide increased granularity for resistance awareness • May be incorporated into disease-state treatment guidelines	• Typically requires manual completion • Less easily understood by prescribers • Lack of incorporation of patient variables (age, gender, and comorbidities) • Lack of correlation with clinical and microbiological outcomes
Weighted incidence syndromic antibiogram (WISCA) Example: Susceptibility of Pseudomonas aeruginosa to TZP among respiratory specimens (obtained among ICU patients only) for male patients age ⩾65 years with heart failure	• Ability to incorporate into electronic healthcare record • Provide real-time decision support for empiric antibiotic therapy recommendations • Integration of patient variables (age, gender, and comorbidities) • Provide empiric antibiotic therapy recommendations for a specific infectious syndrome	• Requires manual completion • Requires collaboration with information technology • Less easily understood by prescribers • Lack of patient variable standardization • Lack of correlation with clinical and microbiological outcomes

CLSI, Clinical and Laboratory Standards Institute; ICU, intensive care unit.