ORIGINAL ARTICLE Occurrence of thermotolerant Campylobacter species in surface waters of a Mediterranean area and in its prevailing pollution sources S. Rodrı´guez and R. Araujo Departament de Microbiologia, Universitat de Barcelona, Barcelona, Spain Introduction Thermotolerant Campylobacter, especially Campylobacter jejuni and Campylobacter coli, are the most common bacterial species causing gastroenteritis in humans world- wide (WHO, 2000). In Spain, they are the main cause of gastroenteritis in children under age 5 (Perez-Ciordia et al. 2001), and in adults, the number of Campylobacter isolations reported to the Spanish Microbiological Infor- mation System has been growing over recent years. In fact, in 2006, the number of Campylobacter isolations was higher than that of Salmonella (Anonymous 2006), which historically has been more prevalent in Spain. Campylobacters are commonly found in natural waters, including rivers, streams and lakes (Bolton et al. 1987; Carter et al. 1987; Popowski et al. 1997). The usual reser- voir is the intestinal tract of livestock, domestic animals, wild birds and poultry so the presence of the bacteria in waters is considered a sign of recent contamination by animal and ⁄ or avian faeces, agricultural run-off or sewage effluents (Jones 2001). Studies on the presence of Campylobacter spp. in aquatic environments have been carried out in countries such as England (Bolton et al. 1987; Obiri-Danso and Jones 1999; Sails et al. 2002), New Zealand (Savill et al. 2001; Eyles et al. 2003; Devane et al. 2005) and the USA (Carter et al. 1987; Vereen et al. 2007). However, there are few studies focused on river and seawater of the Mediterranean area (Alonso and Alonso 1993; Baffone et al. 1995; Moreno et al. 2003). Our study was conducted in a highly populated region near the Mediterranean Sea in northeastern Spain, an area that suffers from water availability problems. Countries Keywords Campylobacter coli, Campylobacter jejuni, faecal indicators, pig slurry, poultry wastewater, surface water, thermotolerant Campylobacter, urban sewage. Correspondence Rosa Araujo, Departament de Microbiologia, Universitat de Barcelona, Av. Diagonal 645, 08028 Barcelona, Spain. E-mail: raraujo@ub.edu 2007 ⁄ 2070: received 24 December 2007, revised 16 February 2010; accepted 17 March 2010 doi:10.1111/j.1365-2672.2010.04725.x Abstract Aims: To determine the prevalence of Campylobacter in surface waters of a highly populated Mediterranean area. Methods and Results: Surface water and wastewater samples were collected from an area in the north-east of Spain during a 2-year study. All the samples were analysed using the MPN method and Multiplex PCR to quantify and identify Campylobacter. It was detected in 82% of the samples from the Llobre- gat River with a mean of 1Æ3 MPN 100 ml )1 . The lowest counts were obtained in summer. Campylobacter coli was the predominant species in this river. The bacteria were isolated from marsh water but not from seawater samples. The highest counts of campylobacters were found in poultry wastewater where Camp. jejuni was the predominant species, as in urban sewage. In pig slurry, Camp. coli was the only species detected. Conclusions: Campylobacter jejuni and Camp. coli are present and widely dis- tributed in the surface water of the studied area. The two species co-exist, with Camp. coli being predominant. In river water, campylobacter counts presented a seasonal distribution. No relationship with faecal indicators was found. Significance and Impact of the Study: This study provides the first data on the occurrence and concentrations of thermotolerant campylobacter species in surface water in a Mediterranean area. Journal of Applied Microbiology ISSN 1364-5072 ª 2010 The Authors Journal compilation ª 2010 The Society for Applied Microbiology, Journal of Applied Microbiology 109 (2010) 1027–1034 1027