ORIGINAL ARTICLE Incidence and antimicrobial resistance of enteropathogens isolated from an integrated aquaculture system R.V. Ribeiro 1 , E.M.F. Reis 2 , C.M.F. Reis 2 , A.C. Freitas-Almeida 3 and D.P. Rodrigues 2 1 Universidade Federal do Rio de Janeiro (UFRJ) – PhD Universidade Estadual do Rio de Janeiro (UERJ), Rio de Janeiro, RJ, Brazil 2 Fundac ¸a ˜ o Instituto Oswaldo Cruz (FIOCRUZ), Rio de Janeiro, RJ, Brazil 3 Universidade Estadual do Rio de Janeiro (UERJ), Rio de Janeiro, RJ, Brazil Introduction The use of wastewater in agriculture and aquaculture has emerged together with the construction of pluvial galleries and sewers in urban areas. Its use has increased in recent decades, especially in arid and semi-arid areas, thus increasing the cost-effectiveness of food production (WHO 1989). The application of appropriate methods for the development, management and use of water resources contributes to the availability of water for sustainable food production (Jime ´nez 2005). The global harvest of wild fish has stagnated at around 90 million tons a year and is not expected to rise (FAO 2007). At the same time, there has been a steady increase in the demand for fish, which has lead to tremendous growth in the global aquaculture ‘industry’. Because of its impact on the environment, it is of utmost importance that the environmental damage often associated with tra- ditional fish farming be avoided during this expansion (Wik et al. 2009). Effluent closed-system recycling has been implemented in pisciculture in the past few years, and it has become an important mechanism for environmental protection, in addition to providing some other observed advantages, such as the cyclic maintenance of nutrients and a shorter fish development period. However, strict food surveillance must be carried out to prevent foodborne illnesses (Wik et al. 2009). This is particularly relevant in areas where the water supply and ⁄ or effects of nutritional loads on surrounding aquatic systems limit the current scale of aquaculture production (Jime ´nez 2005). However a study on health status in communities prac- ticing waste-fed aquaculture indicated that contact with waste-fed ponds and consumption of fish raised in these Keywords Aeromonas, antimicrobial resistance, integrated aquaculture system, Salmonella. Correspondence Roseli Vı´gio Ribeiro, Rua Manuel Pereira da Costa, 28 casa 4. Taua ´ – Ilha do Governador, CEP: 21.920-115, Rio de Janeiro, RJ, Brazil. E-mails: rvigioribeiro@click21.com.br; rvigioribeiro@gmail.com 2010 ⁄ 0540: received 1 April 2010, revised 29 August 2010 and accepted 30 August 2010 doi:10.1111/j.1472-765X.2010.02946.x Abstract Aims: To evaluate an integrated aquaculture system, microbiological analyses of water used in this system were carried out and the incidence and antimicro- bial resistance of enteropathogens were determined in the related ecosystem. Methods and Results: Microbiological analysis was undertaken for Salmonella sp., Shigella sp., Vibrio sp. and Aeromonas sp. The disc-diffusion method was performed according to the Clinical and Laboratory Standards Institute. Water samples tested had 32Æ9% of faecal coliform rates (£1600 per 100 ml) in accor- dance with WHO for pisciculture in wastewater. Salmonella spp. were detected in 14Æ5% of the samples. From a total of 33 strains, 15Æ1% were resistant to one or two antimicrobial drugs tested and multidrug resistance was not observed. Aeromonas spp. were identified in 91Æ6% of the samples. From a total of 416 strains, resistance to one antimicrobial class was observed in 66Æ3% and multidrug resistance in 37Æ7%. Conclusions: This system reflects the community profile, drawing attention to the circulation of pathogens, because the genes coding for resistance to classical antibiotics and broad spectrum are a public health problem. Significance and Impact of the Study: The reuse of water resources requires continuous monitoring as the system is subject to treatment failure, which can result in the spread of bacterial pathogens. Letters in Applied Microbiology ISSN 0266-8254 ª 2010 The Authors Letters in Applied Microbiology 51, 611–618 ª 2010 The Society for Applied Microbiology 611