MOLECULAR MECHANISMS OF BACILLUS PUMILUS 25 SUPER RESISTANCE TO ANTIBIOTICS AND OXIDATIVE STRESS

Abstract

Spore-forming bacteria are residents on the International space station (ISS) and can act as potential biodistructors of structural materials with a consequent disturbance of equipment operation. These bacteria demonstrate high resistance to many stress factors. Molecular mechanisms of this resistance are poorly understood. Sanitary/hygienic monitoring resulted in detection and isolation of strain Bacillus pumilus 25. The investigation was aimed to test B. pumilus 25 resistance to oxidative agents, antibiotics, and to analyze expression of genes associated with the cell response to DNA damage and hydrogen sulfide production. The strain was identified by sequencing 16S RNA and MALDI-TOF analysis. Resistance to stresses and antibiotics was tested with the use of standard microbiological methods. Level of mRNA genes was determined with the real-time polymerase chain reaction. Our results evidence for heightened B. pumilus 25 resistance to the oxidative stress and majority of the antibiotics used in the investigation. This resistance seems to be associated with high expression of the ku-ligD operon genes, and elevated production of hydrogen sulfide.