TABLE 1.
Antimicrobial activity of fusidic acid tested against contemporary staphylococcal clinical isolates from the United States, 2014
| Organisma | No. of isolates | No. of isolates (cumulative %) inhibited at MIC (μg/ml) of: |
MIC50 | MIC90 | ||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| ≤0.015 | 0.03 | 0.06 | 0.12 | 0.25 | 0.5 | 1 | 2 | 4 | 8 | ≥16 | ||||
| S. aureus | 1,804 | 1 (0.1) | 42 (2.4) | 773 (45.2) | 946 (97.7) | 31 (99.4) | 4 (99.6) | 3 (99.8) | 0 (99.8) | 2 (99.9) | 1 (>99.9) | 1 (100.0) | 0.12 | 0.12 |
| MSSA | 956 | 1 (0.1) | 23 (2.5) | 397 (44.0) | 515 (97.9) | 14 (99.4) | 2 (99.6) | 0 (99.6) | 0 (99.6) | 2 (99.8) | 1 (99.9) | 1 (100.0) | 0.12 | 0.12 |
| MRSA | 848 | 19 (2.2) | 376 (46.6) | 431 (97.4) | 17 (99.4) | 2 (99.6) | 3 (100.0) | 0.12 | 0.12 | |||||
| CoNSb | 198 | 11 (5.6) | 101 (56.6) | 65 (89.4) | 2 (90.4) | 0 (90.4) | 0 (90.4) | 5 (92.9) | 6 (96.0) | 8 (100.0) | 0.06 | 0.25 | ||
| MSCoNS | 58 | 2 (3.4) | 33 (60.3) | 22 (98.3) | 1 (100.0) | 0.06 | 0.12 | |||||||
| MRCoNS | 140 | 9 (6.4) | 68 (55.0) | 43 (85.7) | 1 (86.4) | 0 (86.4) | 0 (86.4) | 5 (90.0) | 6 (94.3) | 8 (100.0) | 0.06 | 2 | ||
MSSA, methicillin (oxacillin)-susceptible S. aureus; MRSA, methicillin (oxacillin)-resistant S. aureus; CoNS, coagulase-negative staphylococci; MSCoNS, methicillin (oxacillin)-susceptible CoNS; MRCoNS, methicillin (oxacillin)-resistant CoNS.
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).