Table 1 Conceptual illustration of spectrum score calculation for an antimicrobial regimen
Step 1: Populate susceptibility percentage for organism domains, convert values to ordinal scale (ordinal values shown in parentheses)A,B,C,D | ||||||
|---|---|---|---|---|---|---|
Organism domain | Vancomycin susceptibility (%) | Vancomycin ordinal score | Cefepime susceptibility (%) | Cefepime ordinal score | Vancomycin + cefepime joint susceptibilityB | Vancomycin + cefepime joint ordinal score |
Staphylococcus aureus | 99.3 | 4 | 51.2 | 2 | 99.6 | 4 |
Streptococcus pneumoniae | 98.2 | 4 | 92.5 | 4 | 99.9 | 4 |
Enterococcus faecium | 18.4 | 0 | NA | 0 | 18.4 | 0 |
Enterococcus faecalis | 94.7 | 4 | NA | 0 | 94.7 | 4 |
Escherichia coli | NA | 0 | 92.4 | 4 | 92.4 | 4 |
Klebsiella spp. | NA | 0 | 84.5 | 4 | 84.5 | 4 |
Other enterobacteriaceaeC | NA | 0 | 91.3 | 4 | 91.3 | 4 |
Pseudomonas aeruginosa | NA | 0 | 78.0 | 3 | 78.0 | 3 |
Acinetobacter spp. | NA | 0 | 42.6 | 2 | 42.6 | 2 |
Stenotrophomonas spp. | NA | 0 | 36.6 | 1 | 36.6 | 1 |
Haemophilus influenzae | NA | 0 | 95.4 | 4 | 95.4 | 4 |
Bacteroides spp. | NA | 0 | NA | 0 | NA | 0 |
Legionella spp. | NA | 0 | NA | 0 | NA | 0 |
Mycoplasma spp. | NA | 0 | NA | 0 | NA | 0 |
Step 2: Weight susceptibilities for coverage against intrinsically resistant organisms, sum organism domain scores to create antibiotic regimen spectrum score E | ||||||
Organism domain | Vancomycin weighted ordinal score | Cefepime weighted ordinal score | Vancomycin + cefepime weighted ordinal score | |||
Staphylococcus aureus | 5 | 2.5 | 5 | |||
Streptococcus pneumoniae | 4 | 4 | 4 | |||
Enterococcus faecium | 0 | 0 | 0 | |||
Enterococcus faecalis | 4 | 0 | 4 | |||
Escherichia coli | 0 | 5 | 5 | |||
Klebsiella spp. | 0 | 5 | 5 | |||
Other enterobacteriaceaeC | 0 | 4 | 4 | |||
Pseudomonas aeruginosa | 0 | 5.25 | 5.25 | |||
Acinetobacter spp. | 0 | 2.5 | 2.5 | |||
Stenotrophomonas spp. | 0 | 1 | 1 | |||
Haemophilus influenzae | 0 | 4 | 4 | |||
Bacteroides spp. | 0 | 0 | 0 | |||
Legionella spp. | 0 | 0 | 0 | |||
Mycoplasma spp. | 0 | 0 | 0 | |||
Spectrum Score | 13.0 | 33.25 | 39.75 | |||