Genomic characterization, in vitro, and preclinical evaluation of two microencapsulated lytic phages VB_ST_E15 and VB_ST_SPNIS2 against clinical multidrug-resistant Salmonella serovars.

BACKGROUND: Salmonella infections continue to be one of the essential public health issues threatening millions of people. With the increasing occurrence of resistance against conventionally used antibiotics, the search for alternatives has become crucial. In this study, we aimed to isolate, characterize, and evaluate two lytic bacteriophages against clinically isolated multidrug-resistant (MDR) Salmonella serovars. METHODS: Screening for the phage lytic activity was performed using a spot test. Characterization of the isolated phages was done by determining the host range, longevity test, and the effect of temperature, pH, organic solvents, and morphological characterization using a transmission electron microscope. Genomic analysis was performed using Oxford nanopore sequencing. The lytic activities of the free phage lysates and formulated phage as microencapsulated were evaluated both in vitro and in vivo. RESULTS: Two phages (VB_ST_E15 and VB_ST_SPNIS2) were successfully isolated and showed lytic strong activities against MDR Salmonella (S.) Typhimurium ATCC 14,028, S. Paratyphi A, and S. Typhi. The two phages survived at the tested temperatures, maintained their infectivity for 90 days, and retained their activity until 60 °C with thermal inactivation at 65 °C. They were lytic at a pH range from 3 to 11 but lost their activities at extremely acidic or alkaline pH. The phages could withstand the organic solvents but were completely inactivated by 100% ethanol. Both phages were classified under the order Caudoviricetes, and Genus: Uetakevirus. Their genomic sequences were assembled, annotated, and submitted to the NCBI GenBank database (OR757455 and OR757456). The preclinical evaluation using the murine animal model revealed that the two-phage cocktail managed MDR Salmonella infection as evidenced by the reduction in the bacterial burden, increased animal weight, and histopathological examination. CONCLUSION: The two encapsulated phage formulas could be considered promising candidates for the management of MDR Salmonella-associated infections and clinical analysis should be undertaken to evaluate their potential use in humans.

Evaluation of clinically relevant serum proteins as biomarkers for monitoring COVID-19 severity, and end-organ damage among hospitalized unvaccinated patients.

BACKGROUND: The extensive variability and conflicting information in Coronavirus Disease 2019 (COVID-19) patient data have made it difficult for the medical community to gain a comprehensive understanding and develop clear, reliable guidelines for managing COVID-19 cases. As the world uncovers the diverse side effects of the pandemic, the pursuit of knowledge about COVID-19 has become crucial. The present study aimed to evaluate some clinically relevant serum proteins, providing analysis of the obtained results to employ them in the diagnosis, prognosis, and disease monitoring among COVID-19 patients. METHODS: Samples were collected from 262 COVID-19 unvaccinated hospitalized patients. Measurement of certain serum proteins, namely C-reactive protein (CRP), ferritin, D-dimer, procalcitonin, interleukin-6 (IL-6), serum creatinine (SCr), alanine transaminase (ALT), aspartate transaminase (AST) was done using standard methods. Statistical analysis was performed on the obtained data and the results were correlated to the severity and prognosis. RESULTS: The calculated Mortality rate was found to be 30% with a higher percentage observed among females. The results showed elevation in serum CRP, ferritin, D-dimer, and procalcitonin in most of the patients, also some patients had elevated SCr, ALT, and AST levels indicating end-organ damage. The statistical analysis displayed a strong correlation between serum levels of CRP and ferritin, between D-dimer and ferritin, and between ferritin and procalcitonin. No significant difference was observed between male and female patients' serum levels of the tested serum proteins. A significant correlation between increased serum procalcitonin and mortality was observed. CONCLUSION: The levels of measured serum proteins were impacted by SARS-CoV-2 infection. Serum ferritin, CRP, D-dimer, and procalcitonin are good predicting tools for end-organ damage and acute kidney impairment in COVID-19. Procalcitonin is a strong indicator of severity and mortality in hospitalized COVID-19 patients.

State of the art in epitope mapping and opportunities in COVID-19.

The understanding of any disease calls for studying specific biological structures called epitopes. One important tool recently drawing attention and proving efficiency in both diagnosis and vaccine development is epitope mapping. Several techniques have been developed with the urge to provide precise epitope mapping for use in designing sensitive diagnostic tools and developing rpitope-based vaccines (EBVs) as well as therapeutics. In this review, we will discuss the state of the art in epitope mapping with a special emphasis on accomplishments and opportunities in combating COVID-19. These comprise SARS-CoV-2 variant analysis versus the currently available immune-based diagnostic tools and vaccines, immunological profile-based patient stratification, and finally, exploring novel epitope targets for potential prophylactic, therapeutic or diagnostic agents for COVID-19.

Epitope mapping is an important tool recently proving efficiency in both diagnosis and vaccine development. Several epitope mapping techniques have been developed for designing sensitive diagnostic tools and developing rpitope-based vaccines (EBVs) as well as therapeutics. In this review, we will discuss the state of the art in epitope mapping, emphasizing accomplishments and opportunities in combating COVID-19. These comprise SARS-CoV-2 variant analysis versus the currently available immune-based diagnostic tools and vaccines and exploring novel epitope targets for potential prophylactic, therapeutic or diagnostic agents for COVID-19.

In vivo evaluation of a recombinant N-acylhomoserine lactonase formulated in a hydrogel using a murine model infected with MDR Pseudomonas aeruginosa clinical isolate, CCASUP2.

Failure in the treatment of P. aeruginosa, due to its broad spectrum of resistance, has been associated with increased patient mortality. One alternative approach for infection control is quorum quenching which was found to decrease virulence of such pathogen. In this study, the efficiency of a recombinant Ahl-1 lactonase formulated as a hydrogel was investigated to control the infection of multidrug resistant (MDR) P. aeruginosa infected burn using a murine model. The recombinant N-acylhomoserine lactonase (Ahl-1) was formulated as a hydrogel. To test its ability to control the infection of MDR P. aeruginosa, a thermal injury model was used. Survival rate, and systemic spread of the infection were evaluated. Histopathological examination of the animal dorsal skin was also done for monitoring the healing and cellular changes at the site of infection. Survival rate in the treated group was 100% relative to 40% in the control group. A decrease of up to 3 logs of bacterial count in the blood samples of the treated animals relative to the control group and a decrease of up to 4 logs and 2.3 logs of bacteria in lung and liver samples, respectively were observed. Histopathological examination revealed more enhanced healing process in the treated group. Accordingly, by promoting healing of infected MDR P. aeruginosa burn and by reducing systemic spread of the infection as well as decreasing mortality rate, Ahl-1 hydrogel application is a promising strategy that can be used to combat and control P. aeruginosa burn infections.

Latest updates on SARS-CoV-2 genomic characterization, drug, and vaccine development; a comprehensive bioinformatics review.

Amid the COVID-19 outbreak, several bioinformatic analyses have been conducted on SARS-CoV-2 virus genome. Numerous studies rushed to fill the gap about this novel virus. Comparison with other related sequences, structural predictions of the produced proteins, determination of variations in amino acid residues and depiction of possible drug and vaccine targets have been the focus of scientific research from the beginning of this year. In addition to discussing the viral taxonomy, clinical features, life cycle, and genome organization, this review will focus on the recent updates in genome and viral proteins characterization and potential therapeutic and vaccine candidates developed so far. Comparative studies with related genomes and proteins provide understanding for the viral molecular mechanisms and suggest targets for therapeutics and vaccinology trials to stop the escalation of this new virus. This pandemic, with its resulting social and economic afflictions, will definitely have significant marks on our lives in the following years.

Overexpressed recombinant quorum quenching lactonase reduces the virulence, motility and biofilm formation of multidrug-resistant Pseudomonas aeruginosa clinical isolates.

The increasing occurrence of resistance among Pseudomonas aeruginosa clinical isolates necessitates finding alternatives to antibiotics for controlling the infection of such pathogenic bacteria. In this study, lactonase gene ahl-1 from Bacillus weihenstephanensis isolate-P65 was successfully cloned and expressed in Escherichia coli BL21 (DE3) under the control of T7 promoter for utilizing its quorum quenching activity against three multidrug-resistant (MDR) P. aeruginosa clinical isolates. The biological activity of the overexpressed lactonase enzyme (Ahl-1), tested using a synthetic signal and Chromobacterium violaceum CV026 as a biosensor, displayed good catalytic activity using hexanoyl homoserine lactone (HHL) as a substrate and Chromobacterium violaceum (CV026) as a biosensor (77.2 and 133 nm min-1 for the crude and the purified Ahl-lactonase enzymes, respectively). Upon challenging its ability to inhibit the virulence of three MDR P. aeruginosa clinical isolates, recombinant Ahl-1 successfully prevented the accumulation of acylhomoserine lactone signals resulting in a significant reduction in the investigated virulence determinants; protease (from 40 up to 75.5%), pyocyanin (48-75.9%), and rhamnolipids (52.7-63.4%) (P value < 0.05). Ahl-1 also displayed significant inhibitory activities on the swarming motility and biofilm formation of the three tested MDR P. aeruginosa clinical isolates (P value < 0.05). Consequently, Ahl-1 lactonase enzyme in this study is considered a promising therapeutic agent to inhibit P. aeruginosa pathogenicity with no fear of emergence of resistance.