Arctic Psychrotolerant Pseudomonas sp. B14-6 Exhibits Temperature-Dependent Susceptibility to Aminoglycosides

Bacteria can evade antibiotics by acquiring resistance genes, as well as switching to a non-growing dormant state without accompanying genetic modification. Bacteria in this quiescent state are called persisters, and this non-inheritable ability to withstand multiple antibiotics is referred to as an...

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Bibliographic Details
Published in:Antibiotics
Main Authors: Minjeong Kang, Tae-Rim Choi, Soyeon Ahn, Hee Young Heo, Hyerim Kim, Hye Soo Lee, Yoo Kyung Lee, Hwang-Soo Joo, Philip S. Yune, Wooseong Kim, Yung-Hun Yang
Format: Article in Journal/Newspaper
Language:English
Published: MDPI AG 2022
Subjects:
psychrotolerant bacteria
antibiotic tolerance
persisters
antibiotic resistance
aminoglycosides
Therapeutics. Pharmacology
RM1-950
Arctic
Svalbard
glacier
Online Access:https://doi.org/10.3390/antibiotics11081019
https://doaj.org/article/a051488eb9814908af8073ec8236be74
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Summary:Bacteria can evade antibiotics by acquiring resistance genes, as well as switching to a non-growing dormant state without accompanying genetic modification. Bacteria in this quiescent state are called persisters, and this non-inheritable ability to withstand multiple antibiotics is referred to as antibiotic tolerance. Although all bacteria are considered to be able to form antibiotic-tolerant persisters, the antibiotic tolerance of extremophilic bacteria is poorly understood. Previously, we identified the psychrotolerant bacterium Pseudomonas sp. B14-6 from the glacier foreland of Midtre Lovénbreen in High Arctic Svalbard. Herein, we investigated the resistance and tolerance of Pseudomonas sp. B14-6 against aminoglycosides at various temperatures. This bacterium was resistant to streptomycin and susceptible to apramycin, gentamicin, kanamycin, and tobramycin. The two putative aminoglycoside phosphotransferase genes aph 1 and aph 2 were the most likely contributors to streptomycin resistance. Notably, unlike the mesophilic Pseudomonas aeruginosa PA14, this cold-adapted bacterium demonstrated reduced susceptibility to all tested aminoglycosides in a temperature-dependent manner. Pseudomonas sp. B14-6 at a lower temperature formed the persister cells that shows tolerance to the 100-fold minimum inhibitory concentration (MIC) of gentamicin, as well as the partially tolerant cells that withstand 25-fold MIC gentamicin. The temperature-dependent gentamicin tolerance appears to result from reduced metabolic activity. Lastly, the partially tolerant Pseudomonas sp. B14-6 cells could slowly proliferate under the bactericidal concentrations of aminoglycosides. Our results demonstrate that Pseudomonas sp. B14-6 has a characteristic ability to form cells with a range of tolerance, which appears to be inversely proportional to its growth rate.

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