Salmonella is one of the most common zoonotic foodborne pathogens and a worldwide public health threat. Salmonella enterica is the most pathogenic among Salmonella species, comprising over 2500 serovars. It causes typhoid fever and gastroenteritis, and the serovars responsible for the later disease are known as non-typhoidal Salmonella (NTS). Salmonella transmission to humans happens along the farm-to-fork continuum via contaminated animal- and plant-derived foods, including poultry, eggs, fish, pork, beef, vegetables, fruits, nuts, and flour. Several virulence factors have been recognized to play a vital role in attaching, invading, and evading the host defense system. These factors include capsule, adhesion proteins, flagella, plasmids, and type III secretion systems that are encoded on the Salmonella pathogenicity islands. The increased global prevalence of NTS serovars in recent years indicates that the control approaches centered on alleviating the food animals’ contamination along the food chain have been unsuccessful. Moreover, the emergence of antibiotic-resistant Salmonella variants suggests a potential food safety crisis. This review summarizes the current state of the knowledge on the nomenclature, microbiological features, virulence factors, and the mechanism of antimicrobial resistance of Salmonella. Furthermore, it provides insights into the pathogenesis and epidemiology of Salmonella infections. The recent outbreaks of salmonellosis reported in different clinical settings and geographical regions, including Africa, the Middle East and North Africa, Latin America, Europe, and the USA in the farm-to-fork continuum, are also highlighted.

Fish gut is a versatile organ serving as the primary pathway for invasion by pathogens, particularly parasites, playing a crucial role in modulating the intestinal adaptive immune response. This study aimed to investigate the cellular-mediated reaction, mucosal acidity, and the expression of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), and CD68 in the intestines of catfish, Clarias gariepinus, naturally infected with helminths. Forty catfish were collected from the Nile River and examined for intestinal parasites. The intestinal tissues of the control and infected fish were fixed for histochemical and immunohistochemical studies. Two groups of helminths were found: cestodes Tetracampos ciliotheca and Polyonchobothrium clarias, and nematodes Paracamallanus cyathopharynx, with a prevalence rate of 63.63%, 18.0%, and 18.0%, respectively. Our results showed that the infected fish had a statistically significant rise in the activity of immune cells, including mast cells, eosinophil granular cells, and dendritic cells. This correlated with upregulation in the expressions of PCNA, VEGF, and CD68. Histochemical analyses demonstrated a marked increase in acidic mucus production, Sudan black B, and bromophenol mercury blue. This study enriches our understanding of the evolution of vertebrate immunity in combating intestinal parasitic infections and the host’s adaptive responses.

Cancer is one of the most devastating diseases all over the globe, and it is the second worldwide cause of death, exceeded only by cardiovascular diseases. The therapeutic approach to human cancer has evolved significantly and has varied depending on the type and stage of cancer, as well as the general health status of the patient. Despite the advancements in cancer treatment, various challenges persist in the treatment of cancer, including side effects, drug resistance, and incomplete eradication of tumors. The use of oncolytic bacteria (cancer targeting and destroying bacteria) has been identified to have several advantages over the traditional methods of cancer treatment. Several bacterial species have been identified to be used in the treatment of different types of cancers. Oncolytic therapy can be achieved through the use of a naturally occurring and/or genetically modified bacterial species, including Clostridium , Salmonella, Escherichia coli, and Listeria spp. with their toxins, enzymes, biofilms, and secondary metabolites as well as their spores that leads to direct or indirect killing of cancer cells. This review provides some highlights about the biology and therapeutic potential of oncolytic bacteria individually or in combination with other therapeutic approaches against different types of cancers. Besides, the current challenges and future perspectives will be explored.

The aim of this research was to estimate the immunopotentiation effect of brown algae Padina boergesenii water extract on Nile tilapia, Oreochromis niloticus through resistance to Pseudomonas putida infection. Gas Chromatography Mass Spectrometry was utilized to characterize the seaweed phytoconstituents. One hundred and twenty-six fish were divided in triplicates into two equal groups corresponding to two diet variants that used to feed Nile tilapia for 20 successive days: a basal (control), and P. boergesenii water extract supplemented group. Fish samples were collected at 10-days intervals throughout the experiment. Serum biochemical constituents, total antioxidant capacity (TAC), and some immune related genes expression of the spleen and intestinal tissues of experimental fish were studied, as well as histological examination of fish immune tissues. Moreover, following 20 days of feeding, the susceptibility of Nile tilapia to P. putida infection was evaluated to assess the protective effect of the used extract. The findings indicated that the studied parameters were significantly increased, and the best immune response profiles were observed in fish fed P. boergesenii water extract for 20 successive days. A bacterial challenge experiment using P. putida resulted in higher survival within the supplemented fish group than the control. Thus, the lowered post-challenge mortality of the fish may be related to the protection provided by the stimulation of the innate immune system, reduced oxidative stress by higher activity of TAC, and elevated levels of expression of iterleukin-1beta (IL-1β), beta-defensin (β-defensin), and natural killer-lysin (NKl). Moreover, the constituents of the extract used showed potential protective activity for histological features of the supplemented fish group when compared to the control. Collectively, this study presents a great insight on the protective role of P. boergesenii water extract as an additive in Nile tilapia feed which suggests its potential for improving the immune response against P. putida infection.

Background: Common carp is one of the most economically important freshwater fish species globally. Ammonia exposure, a frequent challenge in aquaculture, can lead to significant economic losses. This study investigated the impact of un-ionized ammonia (UIA) exposure on the expression profiles of three key genes in common carp fry: interleukin-1 beta (IL-1β), corticotropin-releasing hormone (CRH), and leptin a1 (Lep-a1). These genes are crucial indicators of immune response, stress regulation, and appetite control, respectively. Fish were exposed to 0.7 mg/L of UIA, and gene expression was analysed in liver and gill tissues at five time points (12 h, 2-, 4-, 7-, and 14-days of exposure) using quantitative real-time PCR (RT-qPCR). Results: Results demonstrated that expression levels of all three genes were significantly affected by exposure time and tissue type. IL-1β, CRH, and Lep-a1 were upregulated in both liver and gill tissues, with the liver consistently showing higher expression levels. Notably, significant positive correlations were observed between each pair of the three genes studied, suggesting a coordinated physiological response to ammonia stress. The liver emerged as a key organ in orchestrating the long-term adaptive response, while the gills exhibited a more acute, transient reaction. Conclusions: This study provides valuable insights into the molecular mechanisms underlying the physiological response of common carp to ammonia toxicity. The findings highlight the complex interplay between immune, stress, and metabolic pathways in coping with ammonia exposure. A deep understanding of these mechanisms could lead to improved management strategies in aquaculture and the development of potential biomarkers for assessing stress responses in fish populations.