Here, we observed that three MTC species can survive in
soil for 12 months. This observation was verified by the
fact that the negative control plates, which were incubated
in parallel with inoculated plates, remained sterile
throughout the 12-month duration of the experiment,
indicating that the growth of MTC mycobacteria reported
herein did not merely result from contamination of the soil
prior to or after experimental inoculation. Moreover, all of
the colonies were conclusively identified using MALDITOF-
MS as being the same Mycobacterium species as that
used for the inoculation (El Khe´chine et al., 2011). In
particular, non-tuberculosis mycobacteria that are known
as common soil inhabitants (Salah et al., 2009) were not
identified in either control or inoculated plates.