Background:Salmonellosis is one of the most frequent food-borne infections. It iscaused by contaminated food mainly of animal origin, although humanto human transmission and numerous environmental contaminationsmay also be inflicted. Between 30 and 60% of the reported food-borneoutbreaks in the EU are caused by Salmonella and this is the secondmost commonly reported food-borne infection causing gastroenteritis.Salmonella enterica serovar Enteritidis (S. Enteritidis) is the mostwidespread serovar in Europe and other parts of the world.

Methods:In this study we analysed forty-nine S. Enteritidis isolates from veterinaryand food sources in Bulgaria obtained during the period of eight years.We used multiple-locus variable-number of tandem repeats analysis(MLVA) genotyping and the classical antimicrobial resistance (AMR) discdiffusion method to test the diversity of the isolates.

Results:Results showed that isolates were divided into twenty-four MLVA andnine AMR profiles. The calculated Simpsons diversity index was 0.956for MLVA and 0.754 for AMR, respectively. The AMR testing revealed that47% of the isolates were resistant to one and 4% to ≥4 antimicrobials.The most frequent resistotypes were resistance to sulphonamides (n=21)and sensitive to all compounds (n=9). The most frequent MLVA profileswere 3-5-3-3-11 (n=6); 5-13-2-3-11 (n=5); 5-9-2-3-8 (n=5); 6-12-2-3-11(n=4); 5-10-2-3-11 (n=3); 4-5-3-3-9 (n=3). MLVA profiles are presentedaccording to the order of the loci sequenced: SE1, SE2, SE9, SE3 and SE5.We searched for similar S. Enteritidis MLVA profiles in published data. Apartial match was found for some profiles only.

Conclusions:It could be concluded that the MLVA profiles of S. Enteritidis obtained inthis study (the first ones for Bulgaria) have not been frequently isolatedin other counties.