Assessment of bacteriocin production by clinical Pseudomonas aeruginosa isolates and their potential as therapeutic agents.

INTRODUCTION: Bacterial infections and the rising antimicrobial resistance pose a significant threat to public health. Pseudomonas aeruginosa produces bacteriocins like pyocins, especially S-type pyocins, which are promising for biological applications. This research focuses on clinical P. aeruginosa isolates to assess their bacteriocin production, inhibitory spectrum, chemical structure, antibacterial agents, and preservative potential. METHODS: The identification of P. aeruginosa was conducted through both phenotypic and molecular approaches. The inhibitory spectrum and antibacterial potential of the isolates were assessed. The kinetics of antibacterial peptide production were investigated, and the activity of bacteriocin was quantified in arbitrary units (AU ml-1). Physico-chemical characterization of the antibacterial peptides was performed. Molecular weight estimation was carried out using SDS-PAGE. qRT-PCR analysis was employed to validate the expression of the selected candidate gene. RESULT: The antibacterial activity of P. aeruginosa was attributed to the secretion of bacteriocin compounds, which belong to the S-type pyocin family. The use of mitomycin C led to a significant 65.74% increase in pyocin production by these isolates. These S-type pyocins exhibited the ability to inhibit the growth of both Gram-negative (P. mirabilis and P. vulgaris) and Gram-positive (S. aureus, S. epidermidis, E. hirae, S. pyogenes, and S. mutans) bacteria. The molecular weight of S-type pyocin was 66 kDa, and its gene expression was confirmed through qRT-PCR. CONCLUSION: These findings suggest that S-type pyocin hold significant potential as therapeutic agents against pathogenic strains. The Physico-chemical resistance of S-type pyocin underscores its potential for broad applications in the pharmaceutical, hygiene, and food industries.

Vaccine development for zoonotic viral diseases caused by positive­sense single­stranded RNA viruses belonging to the Coronaviridae and Togaviridae families (Review).

Outbreaks of zoonotic viral diseases pose a severe threat to public health and economies worldwide, with this currently being more prominent than it previously was human history. These emergency zoonotic diseases that originated and transmitted from vertebrates to humans have been estimated to account for approximately one billion cases of illness and have caused millions of deaths worldwide annually. The recent emergence of severe acute respiratory syndrome coronavirus-2 (coronavirus disease 2019) is an excellent example of the unpredictable public health threat causing a pandemic. The present review summarizes the literature data regarding the main vaccine developments in human clinical phase I, II and III trials against the zoonotic positive-sense single-stranded RNA viruses belonging to the Coronavirus and Alphavirus genera, including severe acute respiratory syndrome, Middle east respiratory syndrome, Venezuelan equine encephalitis virus, Semliki Forest virus, Ross River virus, Chikungunya virus and O'nyong-nyong virus. That there are neither vaccines nor effective antiviral drugs available against most of these viruses is undeniable. Therefore, new explosive outbreaks of these zoonotic viruses may surely be expected. The present comprehensive review provides an update on the status of vaccine development in different clinical trials against these viruses, as well as an overview of the present results of these trials.

Comparing the Bacteriostatic Effects of Different Metal Nanoparticles Against Proteus vulgaris.

For many years, researchers were looking for new antibacterial substances to deal with hospital infections and especially resistant infections. Nanoparticles attracted much attentions because of their very small size that increases the surface to capacity ratio and consequently increase chemical activity. In this study, the antibacterial effects of silver, copper oxide, nickel oxide, and titanium dioxide nanoparticles were studied on Proteus vulgaris, as a bacterium involved in the resistant hospital infections. The capability of nanoparticles to inhibit the growth of bacteria was assessed via 9 different methods including cylinder, disk, and well-diffusion, spot test, MBC, MIC, liquid inhibitory action test, diffusion, and assessing the effects of nanoparticles on a 24-h culture. Based on the results, copper oxide and silver nanoparticles had high antibacterial effects on P. vulgaris in both liquid and solid cultures, respectively. However, nickel oxide and titanium dioxide nanoparticles only had a weak effect on the inhibition of bacterial growth in the liquid culture. CuO and Ag NPs could release ions and consequently produce free radicals, disturb the equilibrium of electrons between electron donor groups and inactivate enzymes and DNA of the organisms. Moreover, they triggered holes in the bacterial membrane to disturb cellular ion equilibrium. So, they can be used to inhibit the growth of pathogens. Besides, further studies have shown that they could be used as a supplementary treatment and/or in combination with other drugs to cure infections caused by P. vulgaris.