RT journal article
T1 Effects of Ciprofloxacin on Bacterial Abundance and Enrichments in Samples from the Sea-Surface Microlayer and Underlying Waters taken in the Southern North Sea
A1 Adenaya, Adenike
A1 Zumbika, Florence
A1 Rios-Quintero, Ruben
A1 Lara Martín, Pablo Antonio
A1 Wurl, O.
A1 Ribas Ribas, Mariana
A1 Hamprecht, Axel
A1 Brinkhoff, T.
A2 Química Física
K1 sea surface microlayer
K1 coastal waters
K1 antibiotic-resistant bacteria
K1 antibiotics
K1 marine bacteria
K1 southern North Sea
K1 underlying waters
AB The sea surface microlayer (SML), a biofilm-like environment, is a unique and challenginghabitat for microbes, due to its position at the interface between the ocean and theatmosphere. In coastal areas, microbial communities in the SML are often exposed toanthropogenic pollutants, including heavy metals, microplastics, and pharmaceuticals.While studies have been conducted on the effects of some of these pollutants, furtherresearch is needed to understand the impact of antibiotics on the development ofbacterial resistance in the SML. Ciprofloxacin showed high effectiveness against SMLbacteria in a previous study. Thus, we investigated the effects of different concentrationsof this antibiotic on the dynamics of bacterial communities in samples of the SML andthe corresponding underlying water (ULW) over time. Ciprofloxacin concentrations of50 and 100 ng/mL affected bacterial cell numbers and exerted selective pressure onbacterial communities. A non-metric multidimensional scaling (dissimilarity matrix)revealed significant differences in the bacterial community compositions at different timepoints, regardless of the ciprofloxacin concentration, and indicated that the combinationof time and ciprofloxacin concentrations impacts bacterial communities in the SMLand ULW (r2 = 67%, p = 0.001). Marine bacteria of the Rhodobacterales, including thegenera Planktomarina, Lentibacter, and unknown Rhodobacteraceae, persist in thepresence of 100 ng/mL ciprofloxacin over time. The abundance of Campylobacterales,particularly Arcobacteraceae, increased over time and with increasing ciprofloxacinconcentrations, raising concerns about the development and spread of potentialantibiotic-resistant pathogens in the SML and ULW. Ninety-seven bacterial strains(42 marine, 55 non-marine) belonging to 14 genera were also enriched and isolatedin the presence of 100 ng/mL ciprofloxacin. Further antibiotic susceptibility tests onenriched marine bacteria revealed widespread resistance to ciprofloxacin and otherantibiotics found in environmental samples. Our study, therefore, suggests that moreefforts are needed to safeguard the integrity of coastal environments and to mitigatethe spread of antibiotic-resistant bacteria in the ecosystem.
PB Frontiers
SN 1664-302X
YR 2025
FD 2025-08-27
LK http://hdl.handle.net/10498/37893
UL http://hdl.handle.net/10498/37893
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 10-nov-2026