Trends in Salmonella enterica serotypes isolated from human, food, animal, and environment in Tunisia, 1994-2004

Objective: The present study was conducted to investigate, for the first time in Tunisia, the current trends in Salmonella enterica serotypes in Tunisia (human, food, animal, and environment) which would help to improve the control and prevention of Salmonella infections. Methods: Data from 1994 to 2004 from the National Centre of Enteropathogenic Bacteria Pasteur Institute - Tunis, were analysed a total of 16,214 Salmonella isolates that were reported from all over Tunisia and serotyped according to the Kauffman-White scheme. Statistical analysis was done by SPSS v. 11.5 software. Results: The isolation rate was decreasing in the human and food categories only. The top three frequently isolated serotypes during the 11-years were: Enteritidis (25.5%), Anatum (14%), and Corvallis (13.2%), indicating Tunisia as an endemic area for these serotypes. Among human isolates, Enteritidis was the most common serotype, accounting for 24% of all isolates. Among nonhuman isolates, Anatum (28%), Enteritidis (69%), and Corvallis (17.3%) were reported as the first common serotypes for food, animal and environmental samples, respectively. Percentage of Salmonella isolates demonstrated a marked pattern of seasonality, increasing in the warm spring months for human, food and animal isolates. Except for environmental isolates which increased in the spring season. Human salmonellosis outbreak by serotypes Mbandaka, Livingstone, and Typhi Vi+ had been reported during the years: 1997, 1999, 2002 and 2004. Conclusion: Importance of enhancing the Salmonella surveillance system not only in Tunisia but also in the neighboring countries, and the need to get a better monitoring of trends in serotypes over time which would provide information about emerging serotypes and about the efficacy of prevention and control measures. (C) 2007 The British Infection Society. Published by Elsevier Ltd. All rights reserved.