The occurrence of pathogenic bacteria in some ships’ ballast water incoming from various marine regions to the Sea of Marmara, Turkey Gulsen Altug a, * , Sevan Gurun a , Mine Cardak b , Pelin S. Ciftci a , Samet Kalkan a a Istanbul University, Faculty of Fisheries, Department of Marine Biology, Istanbul, Turkey b Canakkale 18 Mart University, Faculty of Fisheries, Canakkale, Turkey article info Article history: Received 14 June 2012 Received in revised form 15 August 2012 Accepted 18 August 2012 Keywords: Ballast water Pathogenic bacteria Antibiotic resistant bacteria Heterotrophic aerobic bacteria The Sea of Marmara abstract The composition and frequency of antibiotic resistance of pathogenic bacteria, the abundance of heterotrophic aerobic bacteria (HPC) and possible in-situ use of chromogenic agar were investigated in the ships’ ballast water coming from different regions of the world to the Sea of Marmara, Turkey for the first time. The samples that were taken from 21 unit ships coming from various marine environments of the Southern China Sea, the Atlantic Ocean, the Mediterranean and the Black Sea to the Sea of Marmara, Turkey in 2009 and 2010 were tested. 38 bacteria species, 27 of them pathogenic bacteria belonging to 17 familia, were detected. Vibrio cholera was not detected in the samples. However, the presence of a high number of HPC, including a cocktail of pathogenic bacteria showed that the ships carry a potential risk for the Sea of Marmara. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Ships need ballast water and often take on a certain amount of water in order to maintain their stability and trim at the start of a voyage. The movement of ballast water between ecosystems was identified as the most important way for the transfer of aquatic non-indigenous species. Occurrences of pathogenic bacteria have potential negative effects on the ecosystem and also on human health. Terrestrial sourced pollution, over-use of living aquatic resources and habitat destruction have been considered as the three greatest menaces to the world’s oceans. Apart from these pollution sources, ship ballast waters are primary carriers for global transport of non-indigenous marine species, harmful aquatic organisms and pathogens. These pollution sources have been identified today to be the fourth greatest danger to the world’s oceans. The rates of non-indigenous species introduced to marine environments via ballast water were estimated to be 30% during the last 20e30 years (Carlton, 1985; Carlton and Geller, 1993; Ruiz et al., 1997; Cohen and Carlton, 1998). It has been well documented that ballast water can contain protozoa, toxic dinoflagellates, metazoa, and the other microor- ganism including pathogenic forms (Medcof, 1975; Carlton, 1985; Williams et al., 1988; Hallegraeff, 1998; Hallegraeff and Bolch, 1991; McCarthy et al., 1992; Carlton and Geller, 1993; McCarthy and Khambaty, 1994; Subba Rao et al., 1994; Gosselin et al., 1995; Galil and Hülsmann, 1997; Pierce et al., 1997; Chu et al., 1997; Gollasch et al., 1998; Hallegraeff, 1998; Lavoie et al., 1999; McCarthy and Crowder, 2000; Ruiz et al., 2000a,b; Drake et al., 2001). The movements of ballast waters from one continent to another via ships cause a global distribution mechanism for pathogenic and antibiotic-resistant forms and the epidemiology of waterborne diseases affecting plants and animals (Ruiz et al., 2000b). Antibi- otics are widely used for treatment of infections in the world. Resistance to clinically relevant antibiotics is common in aquatic bacteria, including potential human pathogens. Thomson et al. (2003) reported that the horizontal gene transfer of antibiotic resistance occurs within ballast tanks. Transportation of bacteria via ballast water from one region to another is increasing antibiotic resistance in marine environments. As a result, mankind must find new antibiotics to take the place of old ones in treatment regimes. Also, the bacteria that cause nosocomial infections are often drug-resistant (Gordis, 2004). Because of its geographical location, the Sea of Marmara is an important water route between the Mediterranean and the Black Sea. The Istanbul Strait connects the Sea of Marmara to the Black Sea and the Çanakkale Strait connects the Sea of Marmara to the Aegean Sea. The Turkish Strait System (TSS) and the Sea of Marmara are under risk due to heavy marine transportation. Annually * Corresponding author. Tel.: þ90 212455 57 00; fax: þ90 2125140379. E-mail address: galtug@istanbul.edu.tr (G. Altug). Contents lists available at SciVerse ScienceDirect Marine Environmental Research journal homepage: www.elsevier.com/locate/marenvrev 0141-1136/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.marenvres.2012.08.005 Marine Environmental Research 81 (2012) 35e42