Antibiotic susceptibility profile of Mycobacterium avium subspecies hominissuis is altered in low-iron conditions

Antibiotic susceptibility testing of the Mycobacterium avium complex is often characterized by a lack of correlation between in vitro results and clinical response. The reason for this discrepancy might lie in the difference between in vitro susceptibility testing conditions and the actual environment experienced by mycobacteria in the host. The availability of iron is one such difference, which is limited in host macrophages upon infection, but abundant in susceptibility testing media. Accordingly, the aim of our study was to determine whether iron limitation affects the antibiotic susceptibility profile of M. avium subspecies hominissuis.