Mycobacterium immunogenum (complex Mycobacteium chelonae - Mycobacterium abscessus): implications for metallurgical and related industries, and in hospital infections. Detection by culture, PCR qualitative or quantitative real - time identification confirmation by sequencing


Information (11/15/04)

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

The interest of this species is mainly due to its involvement in pulmonary processes that can result 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 professional to aerosols generated exposure from fluids used in metal working (MWF: metalworking fluids), can cause skin infections, and respiratory diseases such as bronchitis, asthma, lipoid pneumonia or hypersensitivity pneumonitis (HP: hypersensitivity pneumonitis), 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, and although most affected the process refers to withdraw from exposure to fluids contain this mycobacterium, in other cases progress to chronic interstitial lung disease, with radiological and histological evidence of pulmonary fibrosis.

In these industries recyclable liquid used (MWF: metalworking fluids) of different composition. In general, these liquids, especially those used in metal cutting, are aqueous emulsions with varying content of an oily product, which usually contain, besides 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), in them can easily grow bacteria, and because to 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, also found in cases of hospital seudobrotes, mainly by the use of boncoscopios, using breathing equipment, and acquired infections dialysis units.

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

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