Mechanisms of Resistance to Clinically Significant Antibiotics of Bacterial Strains of the Genus Bacillus Isolated from Samples from the International Space Station

Autor: R. R. Yenikeyev, N. Y. Tatarinova, L. M. Zakharchuk
Rok vydání: 2020
Předmět:
Zdroj: Moscow University Biological Sciences Bulletin. 75:224-230
ISSN: 1934-791X
0096-3925
DOI: 10.3103/s0096392520040045
Popis: The Russian Segment of the International Space Station, as a closed habitat, is a favorable environment for the development of microorganisms. There are bacteria and fungi of various systematic groups, some of which can lead to infections. Thus, certain species of spore-forming bacteria of the genus Bacillus are dangerous. Seven strains of bacteria of this genus isolated from samples obtained at the station showed resistance to β-lactam antibiotics, such as penicillin, ampicillin, meropenem, a number of cephalosporin derivatives I (cefazolin), II (cefuroxime), III (ceftriaxone, cefoperazone, ceftazidime), IV (cefepime) generations, and the aminocyclitol antibiotic spectinomycin. It has been found that all these strains are resistant to penicillin and ampicillin with a minimum inhibitory concentration (MIC) from 16 to 2048 μg/mL as well as to cephalosporin antibiotics and meropenem with a MIC value from 2 to 2048 μg/mL. Bacterial resistance to spectinomycin used in patients with an allergy to β-lactams (penicillins and cephalosporins) is in the MIC range from 32 to 2048 μg/mL. The absence of active efflux pumps in B. licheniformis 7-12 with high MIC values for penicillin and ampicillin suggested that this strain has a β-lactamase defense mechanism against these antibiotics. Three more strains resistant to penicillin and ampicillin—B. subtilis 14-12, Bacillus sp. R2HG21, Bacillus sp. HEP3B2—have another defense mechanism: the active transport of antibiotic from the cell, which is mediated by the presence of efflux pumps functioning due to the electrochemical potential of the cell membrane. In six strains of the studied bacilli, it has been shown that the resistance to cephalosporin derivatives of the third to fourth generations—ceftriaxone, ceftazidime, cefepime and the aminocyclitol antibiotic spectinomycin—is also apparently provided by the systems of active outflow of xenobiotics belonging to the group of secondary transporters.
Databáze: OpenAIRE
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