INTRODUCTION: Salmonella is a leading cause of gastroenteritis in humans and animals, causing typhoidal and non-typhoidal infections that can develop into widespread food- and waterborne outbreaks.
AIM: The incidence of salmonellosis among humans in our country has remained relatively high in recent years despite annual fluctuations. In this work, we aim to clarify the dynamics of the prevalence of salmonella-causing human infections in Bulgaria from 2017 to 2023.
MATERIALS AND METHODS: We used data from annual analyses of isolated Salmonella cultures from patients and contacts of the NRL Enteric Infections, Pathogenic Cocci and Diphtheria.
RESULTS AND DISCUSSION: During the study period, a total of 3208 human salmonellosis cases were laboratory confirmed by bacterial culture isolation, of which 1847 were from patients with enterocolitis syndrome and 1361 from infectious carriers. These cultures belonged to two species of Salmonella enterica and S. bongori, 4 subtypes – enterica, salame, arizonae and diarizonae, and 66 Salmonella serotypes. Salmonella Enteritidis plays the leading etiological role in the patients, occupying a relative share of 47%, followed by Salmonella Typhimurium – 32.8%, and 40.5% are monophasic. Salmonella Infantis ranked third with 4.85%. The following serotypes were isolated for the first time in our country: Brazzaville, Larochelle, Ndolo, Kuoka, Jerusalem, Vejle, and the unique for the world, new serotype –Salmonella 11: z41: enz15. In carriers, in contrast to patients, other serotypes come to the fore Muenster, Bazenheid, Dublin, etc. The data obtained in the analysis again confirm that infants and young children are the group most affected by Salmonella infections. Salmonella outbreaks in the country have been declining sharply since 2020, in contrast to sporadic cases. In 2018, there was an outbreak of a rare serotype, London.
CONCLUSION: Nontyphoidal salmonellosis is a socioeconomic and public health problem that requires control of Salmonella infections in animals and humans. In the effort to contain them, it is necessary to know in detail and follow in dynamics the etiological structure of salmonellosis and to apply non-antibiotic-based approaches such as prophylaxis with probiotics, bacteriophages, and vaccines among farm animals.
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