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Identifier

000403552

Title

Καλλιεργούμενα βακτηριακά στελέχη από το υποθαλάσσιο ηφαίστειο Κολούμπο: ανθεκτικότητα σε αντιβιοτικά, βαρέα μέταλλα και υψηλή οξύτητα

Alternative Title

Cultivated bacterial strains from the submarine volcano Kolumbo: resistance to antibiotics, heavy metals and high acidity

Author

Γαβριηλίδου, Ασημένια Θ.

Thesis advisor

Κεντούρη, Μαρουδιώ

Reviewer

Κωτούλας, Γεώργιος
Καθάριος, Παντελής

Abstract

The extreme environments of Greece are dynamic and highly diverse showing great ecological interest. However, they still remain unexplored and inadequately studied. The extreme environmental conditions prevent the living of higher organisms. Nevertheless, microorganisms are capable of adjusting in hostile conditions and they are expected to develop unique characteristics conferring resistance. Moreover, this adaptation is suspected to induce the multiresistance of microorganisms against different types of chemical/physical stress. This hypothesis is examined in this study. We investigated the resistance of cultivated bacteria isolated from the water column above the hydrothermal vent field of the submarine volcano Kolumbo of Santorini. This region is unique because of the discharge of CO₂-rich hydrothermal fluids, the high acidity within the crater and the rich metal deposits. 54 bacterial strains belonging to three different genera were examined for their resistance to 4 heavy metals, 6 antibiotics, a pH range (from 3.6 to 9.7) and olive oil mill waste with high content of toxic polyphenolic compounds. The applied method is based on monitoring the bacterial growth by measuring the optical density of bacterial subcultures containing serial dilutions of the studied antimicrobial agent in 384-well microplates. We compared the antimicrobial resistance of the bacteria isolated from different depths of the water column, according to the minimum concentration that inhibits 50% of the bacterial growth (MIC50). The bacterial strains from the deeper layer of the water column showed higher resistance to arsenic, antibiotics and lower pH values compared with the bacteria from shallower waters. Furthermore, a higher percentage of the strains from the deeper waters managed to grow in 50%, 25% and 12.5% v/v of olive oil mill waste in relation to the shallower strains. To our knowledge, this is the first report of correlation between antibiotic and high acidity resistance. The results support the fact that Kolumbo’s unique environment has a great impact on its microbial inhabitants. Therefore, Kolumbo serves as an excellent “underwater natural laboratory” for the investigation of important ecological questions and different phenomena, such as the ocean acidification.

Language

Greek

Subject

Antimicrobial resistance

Extreme environments

Ακραία περιβάλλοντα

Ανθεκτικότητα μικροοργανισμών

Issue date

2016-11-18

Collection

School/Department--School of Sciences and Engineering--Department of Biology--Post-graduate theses

Type of Work--Post-graduate theses