Table 5.

MICs of seven antimicrobial agents for the M. fortuitum group reported by four laboratories

DrugMIC (μg/ml) for isolatea:
1351135213531359
Mode (range)% AgreementMode (range)% AgreementMode (range)% AgreementMode (range)% Agreement
Amikacin2 (1–4)1001 (1–2)1001 (1–2)1001 (1)100
Cefoxitin32 (16–64)10064 (16–128)97.216 (2–32)97.216 (2–32)91.7
Ciprofloxacin0.125 (0.125–0.25)1000.125 (0.125–0.5)97.20.125 (0.125–0.25)1001 (0.5–2)100
Clarithromycin64 (0.25–128)27.84 (1–128)61.10.25 (0.03–2)72.20.25 (0.03–0.5)88.9
Doxycycline64 (4–64)97.264 (16–64)97.20.25 (0.25–1)97.20.25 (0.25–1)97.2
Imipenem4 (1–16)66.74 (1–32)58.38 (1–32)75.08 (1–8)66.7
Sulfamethoxazole2 (1–16)77.81 (1–128)41.71 (1–64)86.1b (1–128)55.5
  • a % Agreement, percentage of MICs in each three-dilution range (mode ± log2). High off-scale MICs were converted to the next-highest concentration; low off-scale MICs were left unchanged.

  • b No modal MIC (agreement is the three-dilution range encompassing largest number of MICs).