Study of Antibiotic Resistance of <i>Bacillus</i> Bacteria Isolated from the International Space Station and a Hospital Laboratory

Abstract

Background. To date, there is little data on the clinical characteristics of Bacillus bacteria found in clean rooms and aseptic facilities.The aim of the study was to identify and determine the resistance of Bacillus strains isolated from the International Space Station and medical laboratory to clinically significant antibiotics.Methods. Isolates were identified using 16S rRNA gene analysis, MALDI-TOF, and whole-genome sequencing. Antibiotic sensitivity was assessed using the disk diffusion method.Results. Seven Bacillus strains out of 13 showed resistance to imipenem, and each of B. cereus LR2HG21, HSA01, HSA03, and HSA12 showed resistance to imipenem, ciprofloxacin, levofloxacin, and norfloxacin. Whole-genome sequencing of B. cereus LR2HG21, HSA01, HSA03, HSA12 and B. safensis SE192, resistant to imipenem and meropenem, showed that resistance to them is provided by the TEM-116 gene. In addition to TEM-116, the resistance of B. cereus LR2HG21 to imipenem and meropenem, and B. cereus HSA01 and HSA03 to imipenem, is provided by the BcI and/or BcII genes. Resistance to erythromycin in B. subtilis SE15 and B. subtilis SE171 is encoded by the mphK gene.Conclusion. Resistance to a particular antibiotic in different Bacillus strains can be achieved by one or more mechanisms simultaneously.