TABLE 2.
Antimicrobial activity of fusidic acid and 10 comparator antimicrobial agents tested against staphylococci from the United States, 2014
| Antimicrobial agent | MIC (μg/ml) |
S/I/R (%)a |
|||
|---|---|---|---|---|---|
| MIC50 | MIC90 | Range | CLSI | EUCAST | |
| S. aureus (n = 1,804) | |||||
| Fusidic acid | 0.12 | 0.12 | ≤0.015 to >16 | –/–/– | 99.8/–/0.2 |
| Erythromycin | 16 | >16 | ≤0.12 to >16 | 40.2/5.9/53.9 | 40.4/1.5/58.1 |
| Clindamycin | ≤0.25 | >2 | ≤0.25 to >2 | 83.5/0.2/16.3 | 83.3/0.2/16.5 |
| Vancomycin | 1 | 1 | 0.25 to 2 | 100.0/0.0/0.0 | 100.0/–/0.0 |
| Linezolid | 1 | 1 | 0.25 to >8 | 99.9/–/0.1 | 99.9/–/0.1 |
| Oxacillin | 1 | >2 | ≤0.25 to >2 | 53.0/–/47.0 | 53.0/–/47.0 |
| Tetracycline | ≤0.5 | ≤0.5 | ≤0.5 to >8 | 94.9/0.3/4.8 | 92.3/1.5/6.2 |
| Gentamicin | ≤1 | ≤1 | ≤1 to >8 | 97.7/0.2/2.1 | 97.6/–/2.4 |
| Levofloxacin | 0.25 | >4 | ≤0.12 to >4 | 63.4/0.6/36.0 | 63.4/0.6/36.0 |
| TMP-SMXb | ≤0.5 | ≤0.5 | ≤0.5 to >4 | 97.9/–/2.1 | 97.9/0.1/1.9 |
| Daptomycin | 0.25 | 0.5 | ≤0.06 to 2 | 99.9/–/– | 99.9/–/0.1 |
| MSSA (n = 956) | |||||
| Fusidic acid | 0.12 | 0.12 | ≤0.015 to >16 | –/–/– | 99.6/–/0.4 |
| Erythromycin | 0.25 | >16 | ≤0.12 to >16 | 64.4/7.5/28.1 | 64.7/2.3/33.0 |
| Clindamycin | ≤0.25 | ≤0.25 | ≤0.25 to >2 | 94.9/0.1/5.0 | 94.7/0.2/5.1 |
| Vancomycin | 1 | 1 | 0.5 to 2 | 100.0/0.0/0.0 | 100.0/–/0.0 |
| Linezolid | 1 | 1 | 0.25 to 2 | 100.0/–/0.0 | 100.0/–/0.0 |
| Tetracycline | ≤0.5 | ≤0.5 | ≤0.5 to >8 | 96.1/0.2/3.7 | 94.4/0.3/5.2 |
| Gentamicin | ≤1 | ≤1 | ≤1 to >8 | 99.2/0.0/0.8 | 99.0/–/1.0 |
| Levofloxacin | 0.25 | 2 | ≤0.12 to >4 | 90.0/0.4/9.6 | 90.0/0.4/9.6 |
| TMP-SMX | ≤0.5 | ≤0.5 | ≤0.5 to >4 | 99.2/–/0.8 | 99.2/0.0/0.8 |
| Daptomycin | 0.25 | 0.5 | ≤0.06 to 1 | 100.0/–/– | 100.0/–/0.0 |
| MRSA (n = 848) | |||||
| Fusidic acid | 0.12 | 0.12 | 0.03 to 1 | –/–/– | 100.0/–/0.0 |
| Erythromycin | >16 | >16 | ≤0.12 to >16 | 12.9/4.1/83.0 | 13.1/0.5/86.4 |
| Clindamycin | ≤0.25 | >2 | ≤0.25 to >2 | 70.6/0.4/29.0 | 70.5/0.1/29.4 |
| Vancomycin | 1 | 1 | 0.25 to 2 | 100.0/0.0/0.0 | 100.0/–/0.0 |
| Linezolid | 1 | 1 | 0.25 to >8 | 99.9/–/0.1 | 99.9/–/0.1 |
| Tetracycline | ≤0.5 | 1 | ≤0.5 to >8 | 93.6/0.5/5.9 | 90.0/2.8/7.2 |
| Gentamicin | ≤1 | ≤1 | ≤1 to >8 | 96.1/0.4/3.5 | 96.0/–/4.0 |
| Levofloxacin | 4 | >4 | ≤0.12 to >4 | 33.5/0.7/65.8 | 33.5/0.7/65.8 |
| TMP-SMX | ≤0.5 | ≤0.5 | ≤0.5 to >4 | 96.6/–/3.4 | 96.6/0.3/3.1 |
| Daptomycin | 0.25 | 0.5 | ≤0.06 to 2 | 99.8/–/– | 99.8/–/0.2 |
| CoNSc (n = 198) | |||||
| Fusidic acid | 0.06 | 0.25 | 0.03 to 8 | –/–/– | 90.4/–/9.6 |
| Erythromycin | 16 | >16 | ≤0.12 to >16 | 41.4/2.0/56.6 | 42.4/1.0/56.6 |
| Clindamycin | ≤0.25 | >2 | ≤0.25 to >2 | 70.2/2.5/27.3 | 66.7/3.5/29.8 |
| Vancomycin | 1 | 2 | 0.5 to 4 | 100.0/0.0/0.0 | 100.0/–/0.0 |
| Linezolid | 0.5 | 0.5 | 0.25 to >8 | 99.0/–/1.0 | 99.0/–/1.0 |
| Oxacillin | 1 | >2 | ≤0.25 to >2 | 29.3/–/70.7 | 29.3/–/70.7 |
| Tetracycline | ≤0.5 | >8 | ≤0.5 to >8 | 84.3/2.2/13.6 | 77.8/4.5/17.7 |
| Gentamicin | ≤1 | >8 | ≤1 to >8 | 80.8/3.0/16.2 | 76.8/–/23.2 |
| Levofloxacin | 0.25 | >4 | ≤0.12 to >4 | 60.6/0.0/39.4 | 60.6/0.0/39.4 |
| TMP-SMX | ≤0.5 | >4 | ≤0.5 to >4 | 76.8/–/23.2 | 76.8/12.7/10.6 |
| Daptomycin | 0.25 | 0.5 | ≤0.06 to 1 | 100.0/–/– | 100.0/–/0.0 |
| MSCoNS (n = 58) | |||||
| Fusidic acid | 0.06 | 0.12 | 0.03 to 0.25 | –/–/– | 100.0/–/0.0 |
| Erythromycin | ≤0.12 | >16 | ≤0.12 to >16 | 70.7/1.7/27.6 | 70.7/1.7/27.6 |
| Clindamycin | ≤0.25 | 0.5 | ≤0.25 to >2 | 93.1/1.7/5.2 | 89.7/3.3/6.9 |
| Vancomycin | 1 | 2 | 0.5 to 2 | 100.0/0.0/0.0 | 100.0/–/0.0 |
| Linezolid | 0.5 | 0.5 | 0.25 to 1 | 100.0/–/0.0 | 100.0/–/0.0 |
| Tetracycline | ≤0.5 | 8 | ≤0.5 to >8 | 89.7/1.7/8.6 | 86.2/1.7/12.1 |
| Gentamicin | ≤1 | ≤1 | ≤1 to >8 | 98.3/0.0/1.7 | 96.6/–/3.4 |
| Levofloxacin | 0.25 | >4 | ≤0.12 to >4 | 75.9/0.0/24.1 | 75.9/0.0/24.1 |
| TMP-SMX | ≤0.5 | 4 | ≤0.5 to >4 | 87.9/–/12.1 | 87.9/5.1/6.9 |
| Daptomycin | 0.25 | 0.5 | ≤0.06 to 1 | 100.0/–/– | 100.0/–/0.0 |
| MRCoNS (n = 140) | |||||
| Fusidic acid | 0.06 | 2 | 0.03 to 8 | –/–/– | 86.4/–/13.6 |
| Erythromycin | >16 | >16 | ≤0.12 to >16 | 29.3/2.1/68.6 | 30.7/0.7/68.6 |
| Clindamycin | ≤0.25 | >2 | ≤0.25 to >2 | 60.7/2.9/36.4 | 57.1/3.6/39.3 |
| Vancomycin | 1 | 2 | 0.5 to 4 | 100.0/0.0/0.0 | 100.0/–/0.0 |
| Linezolid | 0.5 | 0.5 | 0.25 to >8 | 98.6/–/1.4 | 98.6/–/1.4 |
| Tetracycline | ≤0.5 | >8 | ≤0.5 to >8 | 82.1/2.2/15.7 | 74.3/5.7/20.0 |
| Gentamicin | ≤1 | >8 | ≤1 to >8 | 73.6/4.3/22.1 | 68.6/–/31.4 |
| Levofloxacin | 0.5 | >4 | ≤0.12 to >4 | 54.3/0.0/45.7 | 54.3/0.0/45.7 |
| TMP-SMX | ≤0.5 | >4 | ≤0.5 to >4 | 72.1/–/27.9 | 72.1/15.9/12.1 |
| Daptomycin | 0.25 | 0.5 | ≤0.06 to 1 | 100.0/–/– | 100.0/–/0.0 |
a
Criteria as published by CLSI and EUCAST for susceptible (S), intermediate (I), and resistant (R) categories (15, 16). –, no criteria for the category.
b
TMP-SMX, trimethoprim-sulfamethoxazole.
c
Includes S. capitis (12 strains), S. caprae (3 strains), S. cohnii (1 strain), S. epidermidis (108 strains), S. haemolyticus (14 strains), S. hominis (14 strains), S. intermedius (2 strains), S. lugdunensis (25 strains), S. pseudintermedius (1 strain), S. saprophyticus (6 strains), S. simulans (7 strains), S. warneri (4 strains), and Staphylococcus species isolates that were not identified to the species level (1 strain).