Mycobacterium vaccae Adaptation to Disinfectants and Hand Sanitisers, and Evaluation of Cross-Tolerance with Antimicrobials

Abstract

Mycobacterium vaccae is being considered as an adjuvant to antituberculosis therapy, tested for the treatment of autoimmune diseases, and as an anti-depressive agent. This bacterium is ubiquitous in the environment and the widespread use of disinfectants and sanitisers may lead to its adaptation to these compounds. In the present study, M. vaccae cells adapted to these compounds mainly by making adjustments in their lipid composition and net surface charge. The modifications in the lipid composition led to changes in membrane permeability which resulted in increased tolerance towards levofloxacin, thioridazine, and omeprazole.

The effect of disinfectants and antiseptics on co- and cross-selection of resistance to antibiotics in aquatic environments and wastewater treatment plants

“…This is supported by a recent study of Morante et al ( 2021 ) which found no relation in Klebsiella pneumoniae isolates resistant to isopropanol and antibiotic resistances. This is contrary to de Carvalho et al ( 2020 ) who showed that Mycobacterium vaccae were more resistant to antibiotics after disinfectant exposure. The strains were exposed for 64 h to ethanol-based hand rubs, causing a change in the fatty acid composition of the cell membrane.…”

“…The resistance of the adapted strains was compared to non-adapted to the antibiotics levofloxacin, teicoplanin and the efflux pump inhibitors thioridazine and omeprazole. All the strains showed a higher resistance than their non-adapted counterparts indicating a cross-resistance through a change in permeability (de Carvalho et al, 2020 ). In a study looking at 16 Mycobacterium chelonae isolates it was found that 50% of the strains were tolerant against 2% glutaraldehyde.…”

Rapidly Growing Mycobacterium Species: The Long and Winding Road from Tuberculosis Vaccines to Potent Stress-Resilience Agents

“…M. vaccae NCTC 11659 is a rapidly growing, aerobic, Gram-positive, acid-alcohol-fast, rod-shaped soil saprophyte, which forms rough yellow pigmented colonies in culture [ 34 ]. Mycobacterium strains can be ubiquitously found in water and soil as well as in manufactured water distribution systems [ 77 , 78 ] and are the dominant taxa in municipal showerheads [ 79 ]. Although mycobacteria are not normally found in the human gut microbiome, they are abundant in the human oral cavity (buccal mucosa and dental plaque) and upper respiratory tract (nostrils and oropharynx) [ 80 ].…”

“…The effects of M. vaccae NCTC 11659 in all of the above-referenced studies are discussed in a more detailed manner in the following sections of this review article. Both M. vaccae NCTC 11659 [ 88 ] and M. vaccae ATCC 15483 T [ 77 ] have peculiar immune modulating properties that are hypothesized to depend on the extraordinary complexity of the cell envelope, a feature characteristic for the whole Mycobacterium genus [ 96 , 97 , 98 , 99 ]. The envelope of mycobacteria adopts a unique dual membrane structure with a waxy outer membrane rich in mycolic acids and free lipids [ 100 , 101 ], a polysaccharide cell wall, and an inner cytoplasmic membrane (reviewed in [ 96 , 97 , 98 ]).…”

Nontuberculous Mycobacterial Resistance to Antibiotics and Disinfectants: Challenges Still Ahead

“…Additionally, formaldehyde is known as a highly effective agent against NTM species; nonetheless, it is a potential carcinogen and is usually used for equipment. Alcohols are commonly used for equipment and surfaces; however, the resistance of some NTM to these compounds has been reported [ 97 ]. In addition, quaternary ammonia, iodophors, phenolics, and autoclave tools can be effective against NTM species.…”