PMC9673151_01
The right finger had an unhealed incision without obvious
exudation.
1678-9946-rimtsp-64-S1678-9946202264076-gf01.jpg
PMC9673151_01_1678-9946-rimtsp-64-S1678-9946202264076-gf01.jpg
f1
Upon physical examination, the right finger had an unhealed incision without obvious exudation (Figure 1).
A) A histopathology examination revealed fibrous connective tissue
hyperplasia, massive inflammatory cell infiltration, and granuloma
formation; B) Ziehl-Neelsen staining revealed positive bacillus in the pus
specimens.
1678-9946-rimtsp-64-S1678-9946202264076-gf02.jpg
PMC9673151_01_1678-9946-rimtsp-64-S1678-9946202264076-gf02.jpg
f2
A histopathology examination revealed fibrous connective tissue hyperplasia, massive inflammatory cell infiltration, and granuloma formation (Figure 2A). Ziehl-Neelsen staining revealed positive bacillus in the pus specimens (Figure 2B).
A) Bacterial colonies were exposed to sunlight for 18 h; B) White
bacterial colonies grow on Columbia blood agar; C) Bacterial colonies
changed from white to yellow after 18h of sunlight exposure.
1678-9946-rimtsp-64-S1678-9946202264076-gf03.jpg
PMC9673151_01_1678-9946-rimtsp-64-S1678-9946202264076-gf03.jpg
f3
Therefore, we used photochromogenicity to distinguish between the two (Figure 3A). In our case, the colonies turned yellow after 18h of incubation in the sun, which helped identify the species as M. marinum (Figure 3B and Figure 3C).