Resisting the Toxic Tide: Multi-Metal Resistance of Bacteria Originating from Contaminated Šibenik Bay Sediments

Ramljak, Ana; Žižek, Marta; Huđ, Anastazija; Palijan, Goran; Lučić, Mavro; Petrić, Ines (2025) Resisting the Toxic Tide: Multi-Metal Resistance of Bacteria Originating from Contaminated Šibenik Bay Sediments. Microorganisms, 13 (10). ISSN 2076-2607

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Abstract

In this study, 74 bacterial isolates were obtained from sediments of Šibenik Bay, which has historically been impacted by heavy metal pollution. Isolates were tested for tolerance to cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), tin (Sn), and zinc (Zn), both individually and in mixtures, and for their biofilm-forming ability. Toxicity followed the trend Hg > Sn > Zn/Cd/Cr > Co/Ni > Pb, with Cu showing resistance across different concentrations. Resistance traits were observed against all tested metals, with some isolates displaying multi-metal resistance to as many as seven metals, reflecting long-term selective pressure in the Bay. The Bacillus species dominated the community (48 isolates across five clusters), confirming this genus as the principal group in metal-polluted sediments. Several less-explored genera, including Ruegeria/Cribrihabitans, Bhargavaea, Pseudoalteromonas, and Lysinibacillus/Sporosarcina, also exhibited notable resistance traits, underscoring their potential as novel candidates for bioremediation. Eleven isolates from Bacillus/Mesobacillus/Cytobacillus, Bacillus/Peribacillus/Rossellomorea, Bacillus/Pseudoalkalibacillus/Alkalibacillus, Lysinibacillus/Sporosarcina, and Ruegeria/Cribrihabitans clusters showed resistance and robust growth under metal mixtures. Among all isolates, 11, 32, 81, and 82 (Bacillus/Mesobacillus/Cytobacillus and Bacillus/Peribacillus/Rossellomorea) combined broad multi-metal tolerance with strong biofilm formation, positioning them as candidates for site-specific, nature-based bioremediation of heavy-metal-impacted coastal ecosystems such as Šibenik Bay.

Item Type:	Article
Uncontrolled Keywords:	bacterial isolates; metal resistance; metal mixtures; contaminated sediments; marine ecosystems
Subjects:	NATURAL SCIENCES > Interdisciplinary Natural Sciences NATURAL SCIENCES > Interdisciplinary Natural Sciences > Marine Science NATURAL SCIENCES > Interdisciplinary Natural Sciences > Environmental Science
Divisions:	Division for Marine and Enviromental Research
Projects:	Project title Project leader Project code Project type Struktura i funkcija mikrobnih zajednica kao karika koja nedostaje pri procjeni stanja okoliša u obalnim zonama pod antropogenim opterećenjem-MicroLink Ines Sviličić Petrić IP-2020-02-6510 HRZZ
Depositing User:	Ana Ramljak
Date Deposited:	12 Nov 2025 09:19
URI:	http://fulir.irb.hr/id/eprint/10195
DOI:	10.3390/microorganisms13102326

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