Protecting food from bacterial contamination is crucial for ensuring its safety and avoiding foodborne illness. Serratia marcescens is one of the food bacterial contaminants that can form biofilms and pigments that spoil the food product and could cause infections and illness to the consumer. Food preservation is essential to diminish such bacterial contaminants or at least reduce their pathogenesis; however, it should not affect food odor, taste, and consistency and must be safe. Sodium citrate is a well-known safe food additive and the current study aims to evaluate its anti-virulence and anti-biofilm activity at low concentrations against S. marcescens. The anti-virulence and antibiofilm activities of sodium citrate were evaluated phenotypically and genotypically. The results showed the significant effect of sodium citrate on decreasing the biofilm formation and other virulence factors, such as motility and the production of prodigiosin, protease, and hemolysins. This could be owed to its downregulating effect on the virulence-encoding genes. An in vivo investigation was conducted on mice and the histopathological examination of isolated tissues from the liver and kidney of mice confirmed the anti-virulence activity of sodium citrate. In addition, an in silico docking study was conducted to evaluate the sodium citrate binding ability to S. marcescens quorum sensing (QS) receptors that regulates its virulence. Sodium citrate showed a marked virtual ability to compete on QS proteins, which could explain sodium citrate’s anti-virulence effect. In conclusion, sodium citrate is a safe food additive and can be used at low concentrations to prevent contamination and biofilm formation by S. marcescens and other bacteria.

The problem of antibiotic resistance is a global critical public health concern. In light of the threat of returning to the pre-antibiotic era, new alternative approaches are required such as quorum-sensing (QS) disruption and virulence inhibition, both of which apply no discernible selective pressure on bacteria, therefore mitigating the potential for the development of resistant strains. Bearing in mind the significant role of QS in orchestrating bacterial virulence, disrupting QS becomes essential for effectively diminishing bacterial virulence. This study aimed to assess the potential use of sub-inhibitory concentration (0.25 mg/mL) of glyceryl trinitrate (GTN) to inhibit virulence in Serratia marcescens and Pseudomonas aeruginosa. GTN could decrease the expression of virulence genes in both tested bacteria in a significant manner. Histopathological study revealed the ability of GTN to alleviate the congestion in hepatic and renal tissues of infected mice and to reduce bacterial and leukocyte infiltration. This study recommends the use of topical GTN to treat topical infection caused by P. aeruginosa and S. marcescens in combination with antibiotics.

Emergence of antimicrobial resistance among the most important bacterial pathogens is recognized as a major public health threat affecting humans worldwide. Infections caused by resistant bacteria lead to up to two-fold higher rates of adverse outcomes compared with similar infections caused by susceptible strains. The negative impacts of antibacterial resistance can be measured at the patient level by increased morbidity and mortality, at the healthcare level by increased resource utilization, higher costs and reduced hospital activity and at the society level by antibiotic treatment guidelines favoring increasingly broad-spectrum empiric therapy.In this study 67 isolates were collected from patients admitted to ICUs of Zagazig University Hospitals, Sharqia, Egypt. The isolates were biochemically identified and their susceptibility to different antimicrobials were tested by Kirby-Bauer standard disk diffusion method.The results showed that the recovered bacteria had high degree of resistance to different antimicrobial classes and 86.25 % were multi drug resistance (MDR). In conclusion high rate of MDR were found in this study that necessitate strict antibiotic dispensing policy to reduce the increased antibiotic resistance.

The emergence of antimicrobial resistance is considered a great problem on a global scale. The decreased supply of antibiotics newly developed adds to this problem needing alternatives such as inhibition of quorum sensing-regulated virulence. Pseudomonas aeruginosa is an opportunistic micror causing nosocomial infections in severely ill and immunocompromised patients. Ubiquitously disseminated in the environment, especially in hospitals, it has become a major threat to human health due to the constant emergence of drug-resistant strains. Quorum sensing inhibitors can attenuate the pathogenesis of bacteria and help the immune system to eradicate them without targeting the bacterial growth.Finasteride was repurposed to test its potential anti-virulence activity against Pseudomonas aeruginosa including biofilm, pyocyanin, protease and swarming motility. Finasteride could siginificntly decreased biofilm formation by 45% , pyocyanin production was diminished to 49% protease and swarming were decreased by 42% and 39% accordingly.In conclusion, finasteride could be employed in treating Pseudomonas aeruginosa infections.