Salmonella is one of the most common and widely distributed foodborne diseases. Contamination of pathogenic microorganisms including Salmonella in wastewater, river, and estuarine water is one of public health problems worldwide. In this study, the serovars and antimicrobial resistance of Salmonella isolated from water samples from nine canals in Bangkok in 2010 were assessed. All studied canals located in Bangkok area were randomly selected by a criterion of positive isolation of salmonellae at least 9 months in 2010. A total of 131 Salmonella isolates were collected in each months of nine individual canals (A to I). The highest number of Salmonella isolates were found in canal E (18), canal B and canal E (17, each). Thirty-one different serovars of Salmonella isolates were identified for serotyping. The top four serovars were Anatum (13.8%), followed by Stanley (13.1%), and Rissen (9.2%), and S. enterica subsp. enterica ser. 4,5,12:i:- (9.2%;). A total of 131 salmonellae isolates were subsequently determined their antimicrobial susceptibility test with 12 antimicrobials agents by disk difference method. The highest resistant rate were found in ampicillin (50.4%), followed by tetracycline (42.7%), streptomycin (26.0%), chloramphenicol (22.9%), trimethoprim-sulfamethoxaole (17.6%), cefotaxime (13.0%), and ceftriaxone (11.5%), and the remainders were less than 10%. However, 33.6% of salmonellae isolates were sensitive to 12 antimicrobial agents, while 66.4% were resistant to at least one tested antimicrobial agent. Additionally, S. enterica subsp. enterica ser. 4,5,12:i- was antimicrobial resistant in the highest frequency 100%, followed by S. Rissen in 91.7%, S. Anatum in 72.2%, and S. Stanley in 52.9%. In this study, triple (13.7%) and more triple (19.8%) antimicrobial resistance patterns were found in the top four serovars isolates, and were resistant to four to ten antimicrobial agents. The occurrence of multidrug-resistane Salmonella in 9 canal water indicated an urgent need for monitoring and controlling the emerging antimicrobial resistance Salmonella in water sources.

Keyword: Salmonella serovars, Canal water, Antimicrobial resistant, Multidrug-resistance