IJUP08 - Universidade do Porto

Survey of the effects of the antibiotic minocycline on freshwater
cyanobacteria
J.Pereira 1 , M. S. Baptista 1,2 , T. Stoichev 2 , B. Heggie 3 , V.M. Vasconcelos 2,4 and
M.T.S.D. Vasconcelos 1,2
1 Department of Chemistry, Faculty of Sciences, University of Porto, Portugal.
2 CIMAR/CIIMAR, Centre of Marine and Environmental Research, University of Porto, Portugal.
3 HOVIONE FarmaCiencia, Portugal.
4 Department of Zoology and Anthropology, Faculty of Sciences, University of Porto, Portugal.
The monitoring of drug residues in the aquatic environment has gained much interest in
recent years, as many pharmaceutical compounds can frequently be found in sewage
treatment plant effluents and freshwater reservoirs at concentrations up to 5 μg L -1 .
Antibiotics are generally believed to be excreted unchanged by the body [1]. They are
specifically designed to penetrate biological membranes and reach universal molecular
systems, thereby increasing the probability of unexpected consequences for a number of
species. Recently, it has been suggested that there is a need to develop ecotoxicity
screening procedures that take into consideration the modes of action of therapeutic drugs
on non-target species [2]. Minocycline hydrochloride, also known as minocycline, is a
member of the tetracycline antibiotics class and has a very broad spectrum of action.
The aim of this study is to determine the effects of minocycline on the growth of the
cyanobacterium Microcystis aeruginosa Kütz., which commonly occurs in Portuguese
freshwater systems. The strain was obtained from Torrão reservoir (Tâmega river) where it
produces toxic blooms every year. To test the influence of the antibiotic, three
concentrations (1, 10, 1000 μg L -1 ) were added to M. aeruginosa growing in f2 medium.
The biological response will be assessed by the growth yield and vitality. The data will be
used to estimate the lowest concentration capable of causing biological effects. The
amount of prescribed minocycline, per year, in the European Union, will be used to
determine if this concentration is likely to occur in Portuguese rivers. Preliminary results
will be presented at the meeting.
This work will contribute with new information on the effects of antibiotics on
phytoplankton. The results obtained may be complemented with surveys of pharmaceutical
compounds in Portuguese freshwater systems, enabling Portugal to face the challenges of
an expected up-coming legislation.
References:
[1] Hircsh, R., Ternes, T., Haberer, K., Kratz, K.L. (1999), Occurrence of antibiotics in the aquatic
environment, The Science of the Total Environment, 225, 109–118.
[2] Daughton, C.G., Ternes, T.A. (1999), Pharmaceuticals and personal care products in the
environment: agents of subtle change?, Environmental Health Perspectives, 107, 907–942.
Acknowledgements: This work was partially funded by Fundação para a Ciência e a Tecnologia, Portugal,
(fellowships awarded to T. Stoichev (SFRH/BPD/32700/2006) and M. Baptista (SFRH/BD/16292/2004) and
the CONC-REEQ/304/2001 re-equipment project) and Reitoria da Universidade do Porto, Portugal, through
the “Investigação na Pré-Graduação” program.
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