Mycobacterium fortuitum

Mycobacterium fortuitum

Description
Gram-positive, nonmotile and acid-fast rods (1-3µm x 0.2-0.4µm). Sometimes long rods with occasional beaded or swollen cells having non-acid-fast ovoid bodies at one end.

Colony characteristics
 * Smooth hemispheric colonies, usually off-white or cream colored colonies. May be butyrous, waxy, multilobate and even rosette clustered (dilute inocula).
 * On Malachite green containing media, such as Löwenstein-Jensen media, colonies can absorb the green dye.

Physiology
 * Rapid growth on Löwenstein-Jensen media within 2-4 days.
 * No growth at 45°C, but grows on MacConkey agar

Differential characteristics
 * Differentiation from M. fortuitum subsp. acetamidolyticum by its ability to utilise L-glutamate and its inability to utilise acetamide as simultaneous nitrogen and carbon source. Both subspecies share an identical 5'-16S rDNA sequence. However, the ITS sequences are different.

Pathogenesis

 * Different types of sporadic infections: pulmonary disease, local abscesses.
 * Postoperative sternal wound infections, endocarditis, meningitis, and osteomyelitis.
 * Has produced postoperative infections after breast augmentation surgury.
 * Biosafety level 2

Type Strain

 * Found world wide in soil, dust, rivers, lakes and tap water.
 * First isolated from a 25-year old patient (syringe abscess) in Rio de Janeiro.
 * Also isolated from lymph glands of cattle and systemic or nodular infection of frogs.

Strain ATCC 6841 = CCUG 20994 = CIP 104534 = DSM 46621 = IFO (now NBRC) 13159 = JCM 6387 = NCTC 10394.

Subsequently, this species has been divided into subspecies M. fortuitum subsp. acetamidolyticum