【国外标准】 Standard Practice for Enumeration of Non-Tuberculosis Mycobacteria in Aqueous Metalworking Fluids by Plate Count Method

5.1 This practice allows for the recovery and enumeration of viable and culturable, non-tuberculosis, rapidly growing Mycobacteria (M. immunogenum, M. chelonae, M. absessus, M. fortuitum, and M. smegmatis) in the presence of high Gram-negative background populations in metalworking fluid field samples. This population is predominantly comprised of Gram-negative bacteria and fungi. Mycobacterial contamination of metalworking fluids has been putatively associated with hypersensitivity pneumonitis (HP) amongst metalgrinding machinists. The detection and enumeration of these organisms will aid in better understanding of occupational health-related problems and a better assessment of antimicrobial pesticide efficacy.5.2 The measurement of viable and culturable mycobacterial densities (Guide E1326), combined with the total mycobacterial counts (including viable culturable (VC), viable nonculturable (VNC) and nonviable (NV) counts), is usually the first step in establishing any possible relationship between Mycobacteria and occupational health concerns (for example, HP).5.3 The practice can be employed in survey studies to characterize the viable-culturable mycobacterial population densities of metalworking fluid field samples.5.4 This practice is also applicable for establishing the mycobacterial resistance of metalworking fluid formulations by determining mycobacterium survival by means of plate count technique.5.5 This practice can also be used to evaluate the relative efficacy of microbicides against Mycobacteria in metalworking fluids.1.1 This practice covers the detection and enumeration of viable and culturable rapidly growing Mycobacteria (RGM), or non-tuberculosis Mycobacteria (NTM) in aqueous metalworking fluids (MWF) in the presence of high non-mycobacterial background population using standard microbiological culture methods.1.2 The detection limit is one colony forming unit (CFU)/mL metalworking fluid.1.3 This practice involves culture of organisms classified as Level 2 pathogens, and should be undertaken by a trained microbiologist in an appropriately equipped facility. The microbiologist should also be capable of distinguishing the diverse colonies of Mycobacteria from other microorganism colonies on a Petri dish and capable of confirming Mycobacteria by acid-fast staining method.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.