ORIGINAL RESEARCH article
Front. Microbiol.
Sec. Extreme Microbiology
This article is part of the Research TopicPsychrotolerant Microbes: Ecological Adaptations and Biotechnological PotentialView all 7 articles
First genome sequence and functional profiling of a Psychrobacter SC65A.3 preserved in 5,000-year-old cave ice: frominsights into ancient resistome, to antimicrobial potential and enzymatic activities
Provisionally accepted
- 1Institute of Biology Bucharest of the Romanian Academy, Bucharest, Romania
- 2Faculty of Biology and the Research Institute of the University of Bucharest, ICUB, University of Bucharest, Bucharest, Romania
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This study reports the first whole-genome sequencing and functional characterization of Psychrobacter sp. SC65A.3 isolated from 5,000-year-old ice in Scarisoara Ice Cave, exhibiting both multidrug-resistance phenotype correlated with clinically important resistance genes and antimicrobial activity. The strain is a polyextremophile, with growth temperatures up to 15℃ (psychrophile) and tolerating 1.9 M NaCl and 0.9 M MgCl₂ (moderate halophile). Phylogenetic analysis based on gyrB and complete genome sequences classified it within the species P. cryohalolentis. Functional assays revealed broad hydrolytic activity and resistance to 10 antibiotics across 8 classes including third generation cephalosporins, fluoroquinolones, aminoglycosides, rifampicin. The genome harbors over 100 genes associated to antimicrobial resistance, some of them of clinical and epidemiological importance (e.g., ampC gyrA, gyrB, parC, parE, dfrA, mcr1, rpoB, tetA, tetC, mcr-1, multiple resistance determinants to heavy metals and multidrug efflux determinants). SC65A.3 exhibited antimicrobial activity against 14 pathogenic strains from the ESKAPE group including methicillin resistant Staphylococcus aureus, Enterococcus faecium, Enterobacter sp., Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii that could be correlated with the presence of genes encoding for antimicrobial compounds such as glycopeptides and bacitracin. Additionally, 45 genes associated with cold- and heat-shock responses were identified, including unique htpX, htpG, and pka genes among cold-adapted Psychrobacter species. Based on its functional and genomic profile, the Psychrobacter strain SC65A.3 can be regarded as an ancient, ice-adapted polyextremophile with significant potential for novel ecological, biotechnological and medical applications. To the best of our knowledge, this study provides the first genome analysis of a Psychrobacter species isolated from an ice cave, as well as the first characterization of ancient resistomes within this largely unexplored environment.
Keywords: Psychrobacter, whole genome sequence, ancient ice resistome, Functional profile, Scarisoara Ice Cave
Received: 25 Sep 2025; Accepted: 18 Dec 2025.
Copyright: © 2025 Paun, Itcus, Chifiriuc and Purcarea. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Cristina Purcarea
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