a blind smear from lj medium revealing pseudomonas aeruginosa talus osteomyelitis after seeking for osteotuberculosis in a 13-year-old teenager: a case report

The lowenstein-jensen is an egg-based microbiology medium that was designed for selective isolation of mycobacterium spp. the main inhibitory composition in this medium is a synthetic dye called malachite green. mycobacterium spp. is resistant to the dye by de-colorization and oxidation of it. some non-tuberculosis organisms may also overcome this inhibitory ingredient by similar enzymatic activity. in the final inspection of the bone tb culture of a teenage patient, the blind smear revealed the pseudomonas talus osteomyelitis. according to the present and similar experiences, the preparation of 1-2 blind smears from tb culturenegative specimens taken from sterile sites of the body may unmask mycobacteria with the atypical colony and non-tuberculosis microorganisms.