Jump to main content
Jump to site search

Issue 10, 2011
Previous Article Next Article

Applicability of photodynamic antimicrobial chemotherapy as an alternative to inactivate fish pathogenic bacteria in aquaculture systems

Author affiliations

Abstract

Aquaculture activities are increasing worldwide, stimulated by the progressive reduction of natural fish stocks in the oceans. However, these activities also suffer heavy production and financial losses resulting from fish infections caused by microbial pathogens, including multidrug resistant bacteria. Therefore, strategies to control fish infections are urgently needed, in order to make aquaculture industry more sustainable. Antimicrobial photodynamic therapy (aPDT) has emerged as an alternative to treat diseases and prevent the development of antibiotic resistance by pathogenic bacteria. The aim of this work was to evaluate the applicability of aPDT to inactivate pathogenic fish bacteria. To reach this objective a cationic porphyrin Tri-Py+-Me-PF was tested against nine pathogenic bacteria isolated from a semi-intensive aquaculture system and against the cultivable bacteria of the aquaculture system. The ecological impact of aPDT in the aquatic environment was also tested on the natural bacterial community, using the overall bacterial community structure and the cultivable bacteria as indicators. Photodynamic inactivation of bacterial isolates and of cultivable bacteria was assessed counting the number of colonies. The impact of aPDT in the overall bacterial community structure of the aquaculture water was evaluated by denaturing gel gradient electrophoresis (DGGE). The results showed that, in the presence of Tri-Py+-Me-PF, the growth of bacterial isolates was inhibited, resulting in a decrease of ≈7–8 log after 60–270 min of irradiation. Cultivable bacteria were also considerably affected, showing decreases up to the detection limit (≈2 log decrease on cell survival), but the inactivation rate varied significantly with the sampling period. The DGGE fingerprint analyses revealed changes in the bacterial community structure caused by the combination of aPDT and light. The results indicate that aPDT can be regarded as a new approach to control fish infections in aquaculture systems, but it is clearly more difficult to inactivate the complex natural bacterial communities of aquaculture waters than pure cultures of bacteria isolated from aquaculture systems. Considering the use of aPDT to inactivate pathogenic microbial community of aquaculture systems the monitoring of microorganisms is needed in order to select the most effective conditions.

Graphical abstract: Applicability of photodynamic antimicrobial chemotherapy as an alternative to inactivate fish pathogenic bacteria in aquaculture systems

Back to tab navigation

Publication details

The article was received on 27 Apr 2011, accepted on 23 Jun 2011 and first published on 09 Aug 2011


Article type: Paper
DOI: 10.1039/C1PP05129F
Citation: Photochem. Photobiol. Sci., 2011,10, 1691-1700
  •   Request permissions

    Applicability of photodynamic antimicrobial chemotherapy as an alternative to inactivate fish pathogenic bacteria in aquaculture systems

    C. Arrojado, C. Pereira, J. P. C. Tomé, M. A. F. Faustino, M. G. P. M. S. Neves, A. C. Tomé, J. A. S. Cavaleiro, Â. Cunha, R. Calado, N. C. M. Gomes and A. Almeida, Photochem. Photobiol. Sci., 2011, 10, 1691
    DOI: 10.1039/C1PP05129F

Search articles by author

Spotlight

Advertisements