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Mycobacterium tusciae , sp. nov. Enrico Tortoli. 19° ESM, Lisbon, July 22-25, 1998. Case report. 7-year old boy suffering from nephrotic syndrome from the age of 3 steroid treatment in the last 4 years cervical lymphadenitis surgical removal no relapse so far. Cultural features.
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Mycobacterium tusciae, sp. nov. Enrico Tortoli 19° ESM, Lisbon, July 22-25, 1998
Case report • 7-year old boy suffering from nephrotic syndrome from the age of 3 • steroid treatment in the last 4 years • cervical lymphadenitis • surgical removal • no relapse so far
Cultural features • growth: slow (4 weeks) • growth temperature: 25°-32°C • pigmentation: scotochromogenic • colonies: rough
Biochemical features • positive reactions: • nitrate reduction • thermostable catalase • urease • Tween 80 hydrolysis • 14-day arylsulfatase • acid phosphatase
Antimicrobial susceptibility Drug MIC Ciprofloxacin 1 Clarithromycin 2 Ethambutol 8 Rifabutin 0.5 Rifampin 0.5 Sparfloxacin 0.5 Streptomycin 2
Lipidic analysis • TLC: • -mycolates • keto-mycolates • wax esters • pattern shared by: M. scrofulaceum, M. interjectum, M. xenopi • Gas-chromatography: • 16:0 30% • 18:1 cis 9 21% • 18:0 alcohol 11% • 18:0 10-methyl 10% • pattern shared by M. scrofulaceum
lmwIS hmwIS M. intracellulare FI-25796 HPLC
16S rDNA sequence • unique sequence both in hypervariable region A and B • short helix 18 • phylogenetic position among rapid growers, close to M. flavescens and M. smegmatis
M. tusciae sp. nov. • Features of the type strain • acid fast rod • G + C content = 66.4 mol% • distinguishable from other scotochromogenic mycobacteria by means of biochemical tests • unique HPLC profile • not identifiable by TLC and GC alone • susceptible to all antimycobacterial drugs • unique sequence within 16S rDNA
Conclusions • M. scrofulaceum is classically considered a major responsible of cervical lymphadenitis • M. tusciae adds to the scotochromogenic mycobacteria recently described as cause of pediatric lymphadenitis • part of pathologies attributed to M. scrofulaceum are probably due to misidentified novel mycobacteria