Serovars of Salmonella strains isolated from foods of animal origin in Belgium

Daube G.*1, J.-M. Dumont2, M.-L. Libotte-Chasseur2, Y. Ghafir1, L. De Zutter3
1  Food Microbiology, Faculty of Veterinary Medicine, University of Liège, Liège, Belgium
2  Public Health Institute - Louis Pasteur, Brussels, Belgium
3  Food Microbiology, Faculty of Veterinary Medicine, University of Ghent, Ghent, Belgium

Salmonella is among the most important meat pathogen worldwide.  The prevalence and the level of contamination are essential for an efficient risk assessment program but all the different serovars have not the same virulence potentiality.
To analyse the repartition of the various serovars in meat from the main animal species, the strains isolated from foods in 1997 by the Belgian zoonosis surveillance program have been serotyped and compared with the most frequent serotypes isolated from human salmonellosis cases in the table above.

Main pathogen serovars of Salmonella in Belgian foods

Main serotypes
(Group)	Human cases*
(n = 12008)	
Cattle
(n = 23)	
Pork
(n = 109)	
Layers
(n = 111)	
Broilers
(n = 146)	
Turkeys
(n = 6)	
S. Enteritidis (D)	51,2 %	-	1,9 %	45 %	34,3 %	33,3 %	
S. Typhimurium (B)	29,3 %	47,8 %	26,4 %	4,5 %	3,5 %	-	
S. Hadar (C)	5 %	-	-	-	20,3 %	33,3 %	
S. Infantis (C)	2,2 %	-	5,7 %	17,1 %	9,8 %	-	
S. Brandenburg (B)	1,8 %	-	15,1 %	-	-	-	
S. Virchow (C)	1,5 %	-	-	1,8 %	10,5 %	16,7 %	
S. Bovismorbificans (C)	1,1 %	-	12,5 %	-	-	-	
S. Derby (B)	1 %	4,3 %	17 %	-	-	-	
Others	6,9 %	47,9 %	31,4 %	31,6 %	21,6 %	16,7 %	
* isolates from the Belgian human salmonellosis cases received from all medical laboratories in 1996

These results are similar than those obtained by the other European countries.  The Salmonella Hadar isolates, an emergent serotype, were only isolated from samples from broilers and turkeys and not from layers, pork or cattle.  Other typing methods, such as lysotyping, genetic typing or antibiotic resistance profile, should be used in order to precise the epidemiological relationship.