Mycobacterium abscessus

Mycobacterium abscessus is a rapidly growing mycobacterium that is a common water contaminant. It was until recently (1992) thought to be a subspecies of Mycobacterium chelonae. M. abcessus can cause chronic lung disease, post-traumatic wound infections, and disseminated cutaneous diseases, mostly in patients with suppressed immune systems.

Description
Microscopy
 * Gram-positive, nonmotile and acid-fast rods (1.0-2.5µm x 0.5µm).

Colony characteristics
 * Colonies on Löwenstein-Jensen media may occur as smooth as well as rough, white or greyish and nonphotochromogenic.

Physiology
 * Growth at 28°C and 37°C after 7 days but not at 43°C.
 * On MacConkey agar at 28°C and even 37°C.
 * Tolerance to 5% NaCl and 500mg/l hydroxylamine (Ogawa egg medium) and 0.2% picrate (Sauton agar medium).
 * Positive degradation of p-aminosalicylate.
 * Production of arylsulfatase but not of nitrate reductase and Tween 80 hydrolase.
 * Negative iron uptake test. No utilisation of fructose, glucose, oxalate and citrate as sole carbon sources.

Differential characteristics
 * M. abscessus and M. chelonae can be distinguished from M. fortuitum or M. peregrinum by their failure to reduce nitrate and to take up iron.
 * Tolerance to 5% NaCl in Löwenstein-Jensen media tolerance to 0.2% picrate in Sauton agar and non-utilisation of citrate as a sole carbon source are characteristics that distinguish M. abscessus from M. chelonae.
 * M. abscessus and M. chelonae sequevar I share an identical sequence in the 54-510 region of 16S rRNA, However, both species can be differentiated by their hsp65 or ITS sequences

Pathogenesis

 * Chronic lung disease, post-traumatic wound infections, post-tympanostomy tube otitis media, disseminated cutaneous diseases in patients of immune suppression.

Type Strain
ATCC 19977 = CCUG 20993 = CIP 104536 = DSM 44196 = JCM 13569 = NCTC 13031