Potentiation of high hydrostatic pressure inactivation of Mycobacterium by combination with physical and chemical conditions

Abstract

Mycobacterium abscessus is an important hospital-acquired pathogen involved in infections associated with medical, surgical, and biopharmaceutical materials. In this work, we investigated the pressure-induced inactivation of two strains [2544 and American Type Culture Collection (ATCC) 19977] of M. abscessus in combination with different temperatures and pH conditions. For strain 2544, exposure to 250MPa for 90min did not significantly inactivate the bacteria at 20°C, whereas at -15°C, there was complete inactivation. Exposure to 250MPa at ≥60°C caused rapid inactivation, with no viable bacteria after 45min. With 45min of exposure, there were no viable bacteria at any temperature when a higher pressure (350MPa) was used. Extremes of pH (4 or 9) also markedly enhanced the pressure-induced inactivation of bacteria at 250MPa, with complete inactivation after 45min. In comparison, exposure of this strain to the disinfecting agent glutaraldehyde (0.5%) resulted in total inactivation within 5min. Strain 19977 was more sensitive to high pressure but less sensitive to glutaraldehyde than strain 2544. These results indicate that high hydrostatic pressure in combination with other physical parameters may be useful in reducing the mycobacterial contamination of medical materials and pharmaceuticals that are sensitive to autoclaving.