Molecular typing, antibiotic resistance, virulence gene and biofilm formation of different Salmonella enterica serotypes

Abstract

Salmonella enterica isolates representing commonly isolated serotypes in Tunisia were analyzed using genotyping and phenotyping methods. ERIC and ITS-PCR applied to 48 Salmonella spp. isolates revealed the presence of 12 and 10 different profiles, respectively. The distribution of profiles among serotypes demonstrated the presence of strains showing an identical fingerprinting pattern. All Salmonella strains used in this study were positive for the sdiA gene. Three Salmonella isolates belonging to serotypes Anatum, Enteritidis and Amsterdam were negative for the invA gene. The spvC gene was detected in thirteen isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Gallinarum and Montevideo. Antibiotic resistance was frequent among the recovered Salmonella isolates belonging to serotypes Anatum, Typhimurium, Enteritidis, Zanzibar and Derby. The majority of these isolates exhibited resistance to at least two antibiotic families. Four multidrug-resistant isolates were recovered from food animals and poultry products. These isolates exhibited not only resistance to tetracycline, sulphonamides, and ampicillin, but also have shown resistance to fluoroquinolones. Common resistance to nalidixic acid, ciprofloxacin and ofloxacin in two S. Anatum and S. Zanzibar strains isolated from raw meat and poultry was also obtained. Furthermore, wastewater and human isolates exhibited frequent resistance to nalidixic acid and tetracycline. Of all isolates, 33.5% were able to form biofilm.Key words: antimicrobial resistance; biofilm; ERIC; ITS; Salmonella enterica; virulence gene Introduction Several species within the genus Salmonella remain a primary cause of gastrointestinal infections worldwide. The pathogenicity of Salmonella depends fundamentally on its virulence factors controlled by chromosomal or plasmidborne determinants. The Salmondlla invasion gene invA is required for invasion into deeper tissue (Swamy et al., 1996). Virulence plasmids are also implicated in survival and multiplication of Salmonella in the reticulo-endothelial system. Both an invasion gene and a virulence plasmid are indispensable for the full expression of virulence. In environmental settings, biofilms represent the common way of life of microorganisms (Latasa et al., 2005). Salmonella is capable for forming biofilms on a variety of biotic and abiotic surfaces. These biofilms enable Salmonella to survive and spread in the environment outside the host (Janssens et al., 2008). Both biofilm production and pathogenicity are controlled and regulated by so-called quorum sensing (QS) systems (Halatsi et al., 2006;Williams, 2006). It has been reported that Salmonella SdiA detects and responds to AHL signals generated only by other microbial species (Sperandio, 2006;Walters and Sperandio, 2006). In response to AHLs, SdiA regulates two Salmonella-specific loci potentially involved in resistance to human complement and intestinal survival or colonization, rck (resistance to complement killing) and srgE (sdiA-regulated gene E).The most commonly incrimi...

Prevalence and Antimicrobial Resistance of <i>Salmonella enterica</i> Isolated from Chicken and Guinea Fowl in Burkina Faso

“…This is in contrast to the result found by Kagambega et al, 2013 [18] who found that all Salmonella Typhimurium isolated from slaughtered poultry were Penta-resistant with the same sequence type ST313. Highly multidrug-resistant Salmonella Typhimurium was also reported in chicken by many authors [39,33]. The finding in this study could be explained by the fact that there is an emergence of a new Salmonella Typhimurium clone among poultry species.…”

Molecular Detection, Virulence Genes, Biofilm Formation, and Antibiotic Resistance of Salmonella enterica Serotype enteritidis Isolated from Poultry and Clinical Samples

“…In general, owing to the administration of antibiotics to improve growth and prevent diseases in food animals, the augmentation of human salmonellosis started with the emergence of foodborne MDR Salmonella (23,38). The information acquired from various studies could be utilized to develop better strategies to eliminate biofilms in the food chain, and accordingly, reduce Salmonella contamination in animal/food chain.…”

Antimicrobial susceptibility of Salmonella Gallinarum and Salmonella Pullorum isolated from ill poultry in Brazil

“…isolated from food producing animals (CLEMENTE et al 2013;DE JONG et al 2014). Although, S. Gallinarum isolated from chickens in Tunisia, were recently reported to be susceptible to all drugs tested (TURKI et al 2014), other studies about the antimicrobial susceptibility profile of animal host-specific Salmonella serovars are still scarce.…”