FIG 1.

Combined activity of omadacycline and another antibiotic against 11 M. abscessus isolates. A fractional inhibitory concentration index (FICI) of ≤0.5 was interpreted as synergy, >0.5 to 4 as indifference, and >4 as antagonism, per the most stringent recommendation (51). The red line at a FICI of 0.5 demarcates synergy (at or below the line) from indifference (above the line). Omadacycline was synergistic with the antibiotic indicated for strains at or below the red line. Each ‘x’ mark denotes a single M. abscessus strain.