Mycobacterium immunogenum (complex Mycobacteium chelonae - Mycobacterium abscessus): implications for metallurgical and related industries, and hospital infections. Detection by culture; Real-time qualitative or quantitaive PCR;  Confirmatory identification (sequencing). 

Information (2011-04-15)

Mycobacterium immunogenum belongs to the Mycobacterium chelonae complex - Mycobacterium abscessus. and they are the mycobacteria most related to processes in which liquids are involved (fluid). These mycobacteria belong to the group of unpigmented, rapid growth mycobacteria (RGM: Rapid Growing Mycobacteria), because they result pigmented colonies in cultures, and require less than 7 days for development in culture. Mycobacterium immunogenum was differentiated from the other two species of the complex by phylogenetic analyses of genes other than the 16S rRNA gene, since it is almost impossible to differentiate them by their phenotypic characteristics, including those evidenced by biochemical tests to determine its metabolic characteristics.

The interest of this species is mainly due to its involvement in pulmonary processes that may cause in operators metallurgical industries, such as automobile manufacturing, and other industries dedicated to cutting, drilling, polishing..., etc., of metals, in which liquids are used for cooling the machine and / or fabricated parts, as well as to lubricate, remove traces of metals and inhibit corrosion of the metal. During use of these liquids, and its professional exposure to the generated aerosols from fluids used in metal working (MWF: metalworking fluids), skin infections, and respiratory diseases such as bronchitis, asthma, lipoid pneumonia or hypersensitivity pneumonitis (HP: hypersensitivity pneumonitis) may occur, which together make up the so - called "lung machine operator (MOL: Operator's lung machine)". The most common process is hypersensitivity pneumonitis (HP: Hypersensitivity Pneumonitis), which is characterized by a granulomatous disease, similar to sarcoidosis. Although most of those affected the process remits upon withdrawal from exposure to fluids containing this mycobacterium, in other cases it progres to chronic interstitial lung disease, with radiological and histological evidence of pulmonary fibrosis.

In these industries recyclable liquid of different composition are used (MWF: metalworking fluids). In general, these liquids, especially those used in metal cutting, are aqueous emulsions with varying content of an oily product, which usually contain, in addition to the lubricant, emulsifiers, defoamers, corrosion inhibitors, biocides, dyes, etc. By containing carbonaceous compounds, especially among oily substances used as lubricants (oil solution of pure petroleum fluids semisynthetic emulsion oil in water, or synthetic fluids emulsion synthetic oil in water), bacteria can easily grow in them, and because mycobacteria are more resistant to biocides (including chlorine, 2% alkaline glutaraldehyde, formaldehyde 8%, ...), colonization by bacteria are not prevented, but can survive and proliferate in these fluids.

This species, Mycobacterium immunogenum, besides causing problems in the metallurgical industries, has also been found in cases of hospital pseudo-outbreaks, mainly due to the use of bronchoscopes, use of assisted breathing equipment, and infections acquired in dialysis units.

This group of mycobacteria (Mycobacterium chelonae Mycobacterium abscessus) has been the most found in water purification systems (83-90% of the species found in these systems), in bio-layers (biofilms) in distilled water supplies, etc.

Tests performed in IVAMI:

  • Isolation conditions required qualitative or quantitative culture of Mycobacterium immunogenum.
  • Qualitative detection genomic PCR amplification by real time TaqMan probe type, in liquid samples used in metallurgical industries, or other liquids that may allow growth of this mycobacterium.
  • Quantitative detection by genomic PCR amplification in real - time taqman probe type, in liquid samples used in metallurgical industries, or other liquids that may allow growth of this mycobacterium.
  • Identification by sequencing, if desired confirmation of the differentiation of related species (Mycobacterium chelonae - Mycobacterium abscessus), by analyzing the appropriate genomic region.

Sample/s recommended/s:

  • Fluids used in manufacturing processes with metals (minimum 100 mL in sealed sterile container, preferably polypropylene to prevent breakage during transportation to the laboratory).
  • Hospital aqueous solutions that can be used with medical devices (bronchoscopes, dialysis processes, breathing equipment, ...) (minimum 100 mL sterile sealed container, preferably polypropylene to avoid breakage during transport to the laboratory)
  • Respiratory exudates in cases of lung infections with hospital bronchoscopes or using breathing equipment (aspirates sealed sterile container, preferably polypropylene to prevent breakage during transportation to the laboratory).
  • Exudates skin infectious lesions (sterile swab Dacron / rayon shank aluminium or plastic impregnated with the lesion, or aspirate the lesion dispensing a preferably sterile tube sealing, polypropylene to prevent breakage during transportation to the laboratory).

Fluid sample volume

  • 100 ml  

Preservation and shipment of sample:

  • Refrigerated (preferred) for less than 2 days.  

Test costs in cutting fluids / industrial washing

  • Quantitative culture (Mycobacteium chelonae complex - Mycobacterium abscessus, M. chelonae without differentiating between M. abscessus and M. immunogenum): Consult to
  • Genomic quantitative detection by real-time PCR (polymerase chain reaction) specific for Mycobacterium immunogenum without detection of other species in the complex: Consult to
  • Genomic quantitative detection by real-time PCR (polymerase chain reaction), specific for Mycobacterium immunogenum: Consult to