Abstract
Salmonella spp. is one of the main causes of foodborne illnesses in humans worldwide. Consequently, great interest exists in reducing its impact on human health by lowering its prevalence in the food chain. Antimicrobial formulations in the form of nanoparticles exert bactericidal action due to their enhanced reactivity resultant from their high surface/volume ratio. Silver nanoparticles (AgNPs) are known to be highly toxic to Gram-negative and Gram-positive microorganisms, including multidrug resistant bacteria. However, few data concerning their success against different Salmonella serovars are available. Aims of the present study were to test the antimicrobial effectiveness of AgNPs, against Salmonella Enteritidis, Hadar, and Senftenberg, and to investigate the causes of their different survival abilities from a molecular point of view. Results showed an immediate, time-limited and serovar-dependent reduction of bacterial viability. In the case of S. Senftenberg, the reduction in numbers was observed for up to 4 h of incubation in the presence of 200 mg/l of AgNPs; on the contrary, S. Enteritidis and S. Hadar resulted to be inhibited for up to 48 h. Reverse transcription and polymerase chain reaction experiments demonstrated the constitutive expression of the plasmidic silver resistance determinant (SilB) by S. Senftenberg, thus suggesting the importance of a cautious use of AgNPs.
Highlights
Salmonella spp. is recognized as one of the main causes of foodborne illnesses in humans worldwide
Particle size distribution www.frontiersin.org from dynamic light scattering (DLS) data agreed with transmission electron microscopy (TEM) data showing a polydisperse sample (PDI = 0.485) with particles having diameters between 5 and >500 nm with the most frequent population having diameters between 6 and 20 nm (Figure 2)
The present study demonstrates that AgNPs can be effective as an antimicrobial even in the case of Salmonella, but that its success is strongly Salmonella strain-dependent, since great differences in terms of effective dose and time of action were observed for the three investigated serovars
Summary
Salmonella spp. is recognized as one of the main causes of foodborne illnesses in humans worldwide. In 2011, a total of 95,548 confirmed cases of human salmonellosis were reported in the EU This microorganism is responsible for the largest number of reported European food-borne outbreaks (26.6% of all outbreaks; EFSA and ECDC, 2013). Two species belong to the genus Salmonella: enterica and bongori. S. enterica includes six subspecies and more than 2500 serovars, based on the Kauffmann–White Le Minor scheme (Grimont and Weill, 2007), with different features in terms of resistance, infectivity, morbidity, and mortality. Even though Salmonella Enteritidis and Typhimurium are the two most frequently isolated serovars among humans (Foley et al, 2011), any serovar is considered capable of causing gastrointestinal illness of varying severity in humans
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
