Diversity of non-typhoidal Salmonella in Algeria

Non-typhoidal Salmonella (NTS) are globally recognized as important pathogens associated with gastroenteritis. In most cases, humans are infected through consumption of contaminated food products, especially food of animal origin. In developing countries including Algeria, there is a lack of documentation, surveillance projects and initiatives. Thus, this has led to an underreporting of Salmonella serovars. The overall aim of this thesis was to identify the different Salmonella serovars isolated from human and poultry in Algeria, and to determine the prevalence of antimicrobial resistance in these isolates. Furthermore, full genome sequences of the isolates were analysed in silico for molecular characterization. Different serovars have been identified among the human isolates, naming S. Typhimurium as the most dominant, followed by S. Kentucky, S. Enteritidis, S. Heidelberg, S. Ohio, S. Lindenburg, S. Indiana, S. Virchow, and S. Bonn. Instead, S. Gallinarum was the only serovar found among the poultry isolates. The isolates displayed resistance to multiple antimicrobials. It was mediated by various genes encoding for resistance to β-lactam antibiotics, carbapenems, quinolones, aminoglycosides and to co-trimoxazole. Classical Salmonella genomic island 1 was identified in serovar Typhimurium, while new variant of SGI1 named SGI1-K7 was identified in serovar Kentucky. Plasmids belonging to incompatibility group FIB and FII were the most commonly identified among the isolates.