Salmonella enterica subsp. arizonae was isolated from 13 of 123 slaughtered pigs in central Greece. The samples cultured were feces, ileum tissue, mesenteric lymph nodes, and gallbladder swabs. A total of 74 isolates from 492 samples were identified as Salmonella spp. by use of standard laboratory culture media and two commercial micromethods and by use of a polyvalent slide agglutination test for the detection of O and H antigens. Among them were 19 (25.68%) suspected to be S. enterica subsp. arizonae according to analysis with standard laboratory culture media. Of those, 14 were identified as S. enterica subsp. arizonae by the API 20E (bioMérieux, France) and the Microgen GnA+B-ID (Microgen Bioproducts, Ltd., United Kingdom) identification systems. All the isolates were tested for resistance to 23 antimicrobials. Strains identified as S. enterica subsp. arizonae were resistant to 17 (70.8%) antibiotics. The highest proportions of resistance were observed for sulfamethoxazole-trimethoprim (71.4%), tetracycline (71.4%), ampicillin (64.3%), and amoxicillin (57.1%). Two isolates were resistant to aztreonam (7.1%) and tigecycline (7.1%), used only for the treatment of humans. Thus, pork meat may play a role in the transmission of antibiotic-resistant S. enterica subsp. arizonae to human consumers. This is the first report of S. enterica subsp. arizonae isolation from pigs.

The genus Salmonella, a group of important zoonotic pathogens, is having global economic and political importance. Its main political importance results from the pathogenicity of many of its serovars for man. Serovars Salmonella Enteritidis and Salmonella Typhimurium are currently the most frequently associated to foodborne infections, but they are not the only ones. Animal food products contaminated from subclinically infected animals are a risk to consumers. In border free markets, an example is the EU, these consumers at risk are international. This is why, economic competition could use the risk of consumer infection either to restrict or promote free border trade in animals and their products. Such use of public health threats increases during economic recessions in nations economically weak to effectively enforce surveillance. In free trade conditions, those unable to pay the costs of pathogen control are unable to effectively implement agreed regulations, centrally decided, but leaving their enforcement to individual states. Free trade of animal food products depends largely on the promotion of safety, included in "quality," when traders target foreign markets. They will overtake eventually the markets of those ineffectively implementing agreed safety regulations, if their offered prices are also attractive for recession hit consumers. Nations unable to effectively enforce safety regulations become disadvantaged partners unequally competing with producers of economically robust states when it comes to public health. Thus, surveillance and control of pathogens like Salmonella are not only quantitative. They are also political issues upon which states base national trade decisions. Hence, the quantitative calculation of costs incurring from surveillance and control of animal salmonelloses, should not only include the cost for public health protection, but also the long term international economic and political costs for an individual state. These qualitative and qualitative costs of man and animal Salmonella infections should be calculated in the light of free trade and open borders. Understandably, accurate calculation of the economic and political costs requires knowledge of the many factors influencing nationally the quality and safety of pork products and internationally free trade. Thus, how Salmonella pig infections affect commerce and public health across open borders depends on a state's ability to accurately calculate costs for the surveillance and control of animal salmonelloses in general, and pig infections as a particular example.

The objective of the present report is the dissemination of information acquired during the application of ISO 6579-1:2017 for the isolation of Salmonella spp. from swine samples. ISO 6579-1:2017 is the protocol officially recommended by the EU for the isolation of Salmonella spp., aiming for the harmonization of effective control of Salmonella infection in food-producing animals. Successful control of animal salmonellosis is highly dependent on the sensitivity and reliability of the biochemical methods used to detect the presence of the pathogen in various stages of food production. Application of ISO 6579-1:2017 resulted in the isolation of twelve Salmonella spp. and eighteen other members of the family of Enterobacteriaceae biochemically and other bacteria antigenically resembling salmonellae. An evaluation of the culture media was conducted, including xylose-lysine-desoxycholate agar (XLD), Salmonella–Shigella Agar (SS), Brilliant Green Agar (BGA), Salmonella Chromogenic Agar (SCA), Triple Sugar Iron (TSI), and modified semi-solid Rappaport–Vassiliadis (MSRV) agar. The evaluation showed that these culture-selective media differed significantly in their performance for the isolation of Salmonella from swine samples. It was concluded that the presence of atypical Salmonella strains negatively affects the prevalence of Salmonella, thus affecting the identification of carrier pigs and eventually affecting the efficiency of control programs. Thus, doubtful results require additional biochemical testing to confirm the accuracy of such universally recommended isolation methods.

The presence of Gram-negative bacteria species, other than Salmonella spp., in the gallbladder of pigs was examined. Isolated Gram-negative bacteria were assigned to species using the Microgen™ GnA+B-ID Systems. Of the 64 isolated strains 43 were identified as Escherichia coli, seven as Enterobacter spp., three each as Klebsiella spp., Citrobacterfreundii, Aeromonas hydrophila and Cronobacter sakazakii and one each as Escherichiafergusonii and Trabulsiella guamensis. Their antibiograms showed very high resistance to ampicillin, amoxicillin, tetracycline, chloramphenicol and sulfamethoxazole/trimethoprim. It was concluded that the pigs' gallbladder is a reservoir of potentially pathogenic Gram-negative bacteria for pork consumers.

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The design of new medical devices in biomedical engineering often necessitates the control of microbial load at the point of application, making antibacterial action valuable for numerous applications in the biomedical field. Nanotechnology products, such as silver nanoparticles (AgNPs), represent highly promising yet underexplored bioactive and antimicrobial agents that have attracted researchers’ interest for integration into medical devices. This study focuses on stable suspensions of silver nanoparticles, characterized by using a range of complementary physicochemical techniques as well as bacterial cell cultures, while also demonstrating controlled entrapment of the nanoparticles in collagen-based gels. The findings reveal that highly stable suspensions of negatively charged AgNPs (~6 nm in size) consistently exhibit broad-spectrum antimicrobial activity against both Gram-negative and Gram-positive bacteria, with minimum inhibitory concentration values of 10–20 ppm, whilst, importantly, close contact between the nanoparticles and bacterial cells turns out to be essential for their antibacterial action. Controlled entrapment of the nanoparticles in collagen-based gels enables regulation of nanoparticle release and their antimicrobial efficacy. This work highlights the promising prospects of silver nanoparticles in designing novel biomedical engineering products, while underscoring the need for a more comprehensive understanding of their biological activity to ensure optimal utilization.