Transcriptome Analysis of Salmonella Heidelberg after Exposure to Cetylpyridinium Chloride, Acidified Calcium Hypochlorite, and Peroxyacetic Acid

Transcriptomic signature of bacteria exposed to benzalkonium chloride

The COVID-19 pandemic has highlighted our reliance on biocides, the increasing prevalence of resistance to biocides is a risk to public health. Bacterial exposure to the biocide, benzalkonium chloride (BAC), resulted in a unique transcriptomic profile, characterised by both a short and long-term response. Differential gene expression was observed in four main areas: motility, membrane composition, proteostasis, and the stress response. A metabolism shift to protect the proteome and the stress response were prioritised suggesting these are main resistance mechanisms. Whereas "well-established" mechanisms, such as biofilm formation, were not found to be differentially expressed after exposure to BAC.

Alternative Additives for Organic and Natural Ready-to-Eat Meats to Control Spoilage and Maintain Shelf Life: Current Perspectives in the United States

Food additives are employed in the food industry to enhance the color, smell, and taste of foods, increase nutritional value, boost processing efficiency, and extend shelf life. Consumers are beginning to prioritize food ingredients that they perceive as supporting a healthy lifestyle, emphasizing ingredients they deem acceptable as alternative or "clean-label" ingredients. Ready-to-eat (RTE) meat products can be contaminated with pathogens and spoilage microorganisms after the cooking step, contributing to food spoilage losses and increasing the risk to consumers for foodborne illnesses. More recently, consumers have advocated for no artificial additives or preservatives, which has led to a search for antimicrobials that meet these demands but do not lessen the safety or quality of RTE meats. Lactates and diacetates are used almost universally to extend the shelf life of RTE meats by reducing spoilage organisms and preventing the outgrowth of the foodborne pathogen Listeria monocytogenes. These antimicrobials applied to RTE meats tend to be broad-spectrum in their activities, thus affecting overall microbial ecology. It is to the food processing industry's advantage to target spoilage organisms and pathogens specifically.

Non-Antibiotics Strategies to Control Salmonella Infection in Poultry

Salmonella spp. is a facultative intracellular pathogen causing localized or systemic infections, involving economic and public health significance, and remains the leading pathogen of food safety concern worldwide, with poultry being the primary transmission vector. Antibiotics have been the main strategy for Salmonella control for many years, which has allowed producers to improve the growth and health of food-producing animals. However, the utilization of antibiotics has been reconsidered since bacterial pathogens have established and shared a variety of antibiotic resistance mechanisms that can quickly increase within microbial communities. The use of alternatives to antibiotics has been recommended and successfully applied in many countries, leading to the core aim of this review, focused on (1) describing the importance of Salmonella infection in poultry and the effects associated with the use of antibiotics for disease control; (2) discussing the use of feeding-based (prebiotics, probiotics, bacterial subproducts, phytobiotics) and non-feeding-based (bacteriophages, in ovo injection, vaccines) strategies in poultry production for Salmonella control; and (3) exploring the use of complementary strategies, highlighting those based on -omics tools, to assess the effects of using the available antibiotic-free alternatives and their role in lowering dependency on the existing antimicrobial substances to manage bacterial infections in poultry effectively.

Impact of the Resistance Responses to Stress Conditions Encountered in Food and Food Processing Environments on the Virulence and Growth Fitness of Non-Typhoidal Salmonellae

The success of Salmonella as a foodborne pathogen can probably be attributed to two major features: its remarkable genetic diversity and its extraordinary ability to adapt. Salmonella cells can survive in harsh environments, successfully compete for nutrients, and cause disease once inside the host. Furthermore, they are capable of rapidly reprogramming their metabolism, evolving in a short time from a stress-resistance mode to a growth or virulent mode, or even to express stress resistance and virulence factors at the same time if needed, thanks to a complex and fine-tuned regulatory network. It is nevertheless generally acknowledged that the development of stress resistance usually has a fitness cost for bacterial cells and that induction of stress resistance responses to certain agents can trigger changes in Salmonella virulence. In this review, we summarize and discuss current knowledge concerning the effects that the development of resistance responses to stress conditions encountered in food and food processing environments (including acid, osmotic and oxidative stress, starvation, modified atmospheres, detergents and disinfectants, chilling, heat, and non-thermal technologies) exerts on different aspects of the physiology of non-typhoidal Salmonellae, with special emphasis on virulence and growth fitness.

Antimicrobial resistance associated with the use of antimicrobial processing aids during poultry processing operations: cause for concern?

Antimicrobial resistance has become a global issue and a threat to human and animal health. Contamination of poultry carcasses with meat-borne pathogens represents both an economic and a public health concern. The use of antimicrobial processing aids (APA) during poultry processing has contributed to an improvement in the microbiological quality of poultry carcasses. However, the extensive use of these decontaminants has raised concerns about their possible role in the co-selection of antibiotic-resistant bacteria. This topic is presented in the current review to provide an update on the information related to bacterial adaptation to APA used in poultry processing establishments, and to discuss the relationship between APA bacterial adaptation and the acquisition of a new resistance phenotype to therapeutic antimicrobials by bacteria. Common mechanisms such as active efflux and changes in membrane fluidity are the most documented mechanisms responsible for bacterial cross-resistance to APA and antimicrobials. Although most studies reported a bacterial resistance to antibiotics not reaching a clinical level, the under-exposure of bacteria to APA remains a concern in the poultry industry. Further research is needed to determine if APA used during poultry processing and therapeutic antimicrobials share common sites of action in bacteria and encounter similar mechanisms of resistance.

Cetylpyridinium Chloride: Mechanism of Action, Antimicrobial Efficacy in Biofilms, and Potential Risks of Resistance

Antimicrobial resistance is a serious issue for public health care all over the world. While resistance toward antibiotics has attracted strong interest among researchers and the general public over the last 2 decades, the directly related problem of resistance toward antiseptics and biocides has been somewhat left untended. In the field of dentistry, antiseptics are routinely used in professional care, but they are also included in lots of oral care products such as mouthwashes or dentifrices, which are easily available for consumers over-the-counter. Despite this fact, there is little awareness among the dental community about potential risks of the widespread, unreflected, and potentially even needless use of antiseptics in oral care. Cetylpyridinium chloride (CPC), a quaternary ammonium compound, which was first described in 1939, is one of the most commonly used antiseptics in oral care products and included in a wide range of over-the-counter products such as mouthwashes and dentifrices. The aim of the present review is to summarize the current literature on CPC, particularly focusing on its mechanism of action, its antimicrobial efficacy toward biofilms, and on potential risks of resistance toward this antiseptic as well as underlying mechanisms. Furthermore, this work aims to raise awareness among the dental community about the risk of resistance toward antiseptics in general.

Transcriptomic Analysis, Motility and Biofilm Formation Characteristics of Salmonella typhimurium Exposed to Benzyl Isothiocyanate Treatment

Salmonella typhimurium (S. typhimurium) is a common foodborne pathogen that not only causes diseases and contaminates food, but also causes considerable economic losses. Therefore, it is necessary to find effective and feasible methods to control S. typhimurium. In this study, changes in S. typhimurium after treatment with benzyl isothiocyanate (BITC) were detected by transcriptomics to explore the antibacterial effect of BITC at subinhibitory concentration. The results showed that, in contrast to the control group (SC), the BITC-treated group (SQ_BITC) had 197 differentially expressed genes (DEGs), of which 115 were downregulated and 82 were upregulated. We screened out eight significantly downregulated virulence-related genes and verified gene expression by quantitative Real-time Polymerase Chain Reaction (qRT-PCR). We also selected motility and biofilm formation to observe the effects of BITC on the other virulence related factors of S. typhimurium. The results showed that both swimming and swarming were significantly inhibited. BITC also had a significant inhibitory effect on biofilm formation, and showed an effect on bacterial morphology. These results will be helpful for understanding the mechanism of the antibacterial action of BITC against S. typhimurium and other foodborne pathogens.