Experimental salmonellosis challenge model in older calves

An Experimental Infection Model in Sheep and Goats to Evaluate Salmonella Colonization in Deep Tissue Lymph Nodes and after Carcass Vascular Rinsing with Bacteriophages in Goats

An animal infection model was evaluated on sheep and goats to confirm which species infected with Salmonella enterica serovar Enteritidis C StR (SE13) would provide a consistent and high frequency of Salmonella colonization in lymph nodes (LNs) without causing undue animal morbidity. Sheep and goats (n = 5) were intradermally inoculated with Salmonella, postincubated for 7 days, and euthanized. Superficial cervical, medial iliac, subiliac, mammary, and popliteal LNs were excised from each carcass. Goat LNs had approximately 53% greater Salmonella level compared to sheep. Also, Salmonella was inconsistently recovered from the sheep LNs. Thus, goats were selected to determine the ability of carcass vascular rinsing (with and without bacteriophages) to reduce Salmonella in infected LNs. Goats with similar characteristics were grouped together before being randomly assigned to 3 postharvest treatments; control (CN, not vascularly rinsed; n = 10), vascularly rinsed with a standard Rinse & Chill® solution (RC; 98.5% water and a blend of saccharides and phosphates; n = 10), or vascularly rinsed with a standard Rinse & Chill® solution plus the addition of bacteriophages (BP; n = 10). Rinse & Chill® system was able to successfully deliver a mean 7.0 log PFU/g to the S. Enteritidis-infected LNs (mean 3.5 log CFU/g). However, neither Rinse & Chill® without bacteriophages nor with bacteriophages caused Salmonella reduction (P > 0.05) compared to the nonrinsed goat carcasses.

Bacterial Causes of Intestinal Disease in Dairy Calves: Acceptable Control Measures

Although diarrhea in dairy calves is common, it is not always due to bacteria. Escherichia coli, Salmonella, and Clostridium perfringens are the most commonly implicated bacteria, but an etiologic diagnosis should be sought before specific treatment is instituted. Nonspecific treatment such as fluid, electrolyte, and nutritional support should be accomplished while diagnostics are pending. Antimicrobials should not be a first-line therapy for calf diarrhea. Control measures are discussed.

Host defense peptides identified in human apolipoprotein B as novel food biopreservatives and active coating components

The effectiveness of three novel "host defence peptides" identified in human Apolipoprotein B (ApoB) as novel antimicrobial and antibiofilm agents to be employed in food industry is reported. ApoB-derived peptides have been found to exert significant antimicrobial effects towards Salmonella typhimurium ATCC® 14028 and Salmonella enteritidis 706 RIVM strains. Furthermore, they have been found to retain antimicrobial activity under experimental conditions selected to simulate those occurring during food storage, transportation and heat treatment, and have been found to be endowed with antibiofilm properties. Based on these findings, to evaluate the applicability of ApoB-derived peptides as food biopreservatives, coating solutions composed by chitosan (CH) and an ApoB-derived peptide have been prepared and found to be able to prevent Salmonella cells attachment to different kinds of surfaces employed in food industry. Finally, obtained coating solution has been demonstrated to hinder microbial proliferation in chicken meat samples. Altogether, obtained findings indicate that ApoB-derived peptides are promising candidates as novel biopreservatives for food packaging.

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review

Zoonoses are diseases transmitted from animals to humans, posing a great threat to the health and life of people all over the world. According to WHO estimations, 600 million cases of diseases caused by contaminated food were noted in 2010, including almost 350 million caused by pathogenic bacteria. Campylobacter, Salmonella, as well as Yersinia enterocolitica and Listeria monocytogenes may dwell in livestock (poultry, cattle, and swine) but are also found in wild animals, pets, fish, and rodents. Animals, often being asymptomatic carriers of pathogens, excrete them with faeces, thus delivering them to the environment. Therefore, pathogens may invade new individuals, as well as reside on vegetables and fruits. Pathogenic bacteria also penetrate food production areas and may remain there in the form of a biofilm covering the surfaces of machines and equipment. A common occurrence of microbes in food products, as well as their improper or careless processing, leads to common poisonings. Symptoms of foodborne infections may be mild, sometimes flu-like, but they also may be accompanied by severe complications, some even fatal. The aim of the paper is to summarize and provide information on campylobacteriosis, salmonellosis, yersiniosis, and listeriosis and the aetiological factors of those diseases, along with the general characteristics of pathogens, virulence factors, and reservoirs.

Vaccination against Salmonella Infection: the Mucosal Way

Salmonella enterica subspecies enterica includes several serovars infecting both humans and other animals and leading to typhoid fever or gastroenteritis. The high prevalence of associated morbidity and mortality, together with an increased emergence of multidrug-resistant strains, is a current global health issue that has prompted the development of vaccination strategies that confer protection against most serovars. Currently available systemic vaccine approaches have major limitations, including a reduced effectiveness in young children and a lack of cross-protection among different strains. Having studied host-pathogen interactions, microbiologists and immunologists argue in favor of topical gastrointestinal administration for improvement in vaccine efficacy. Here, recent advances in this field are summarized, including mechanisms of bacterial uptake at the intestinal epithelium, the assessment of protective host immunity, and improved animal models that closely mimic infection in humans. The pros and cons of existing vaccines are presented, along with recent progress made with novel formulations. Finally, new candidate antigens and their relevance in the refined design of anti-Salmonella vaccines are discussed, along with antigen vectorization strategies such as nanoparticles or secretory immunoglobulins, with a focus on potentiating mucosal vaccine efficacy.