Presence of a large foreign workforce and the annual gathering of people for pilgrimage from around the globe have significantly contributed to the emergence and diversity of respiratory viruses in Saudi Arabia. Here, we report the sequence and phylogenetic analysis of the H3N2 subtype of influenza A virus (IAV) in clinical samples collected from Riyadh, Saudi Arabia. Based on RT-PCR, IAV was found in 88 (28.3%) of the 311 samples screened. Of the 88-IAV positive samples, 43 (48.8%) were H1N1 subtype while the remaining 45 (51.2%) were found to be of the H3N2 subtype. Complete sequencing of HA and NA genes of H3N2 revealed, twelve and nine amino acid (AA) substitutions respectively, and importantly, these variations are absent in the current vaccine strains. Based on the phylogenetic analysis, the majority of H3N2 strains were grouped in the same clades as the vaccine strains. Importantly, the N-glycosylation sites at AA 135(NSS) were found to be unique to 6 strains in the investigated HA1 protein and were absent in the current vaccine strains. These data may have significant clinical implications in designing novel and population-based vaccines for IAV and underscore the need for regular monitoring of efficacy of vaccines due to emerging variants.

The present study explores the simple and eco-friendly green synthesis of silver (AgNPs) and gold (AuNPs) nanoparticles using aqueous flower extract of Bombax ceiba, commonly known as silk cotton. The extract, rich in flavonoids, serves as both a reducing and capping agent, facilitating the synthesis of metal nanoparticles. The synthesized nanoparticles were characterized using UV spectroscopy and scanning electron microscopy (SEM), confirming their formation and stability. The antibacterial activity of the AgNPs, AuNPs, and crude flavonoids was evaluated against several bacterial strains, including Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, and Staphylococcus aureus, using the agar well diffusion method. Our results show that AgNPs exhibit significant antibacterial activity, particularly against Gram-negative bacteria, with a marked zone of inhibition observed for S. typhi and E. coli. The inhibition zone increased with higher concentrations of AgNPs. In contrast, AuNPs and flavonoid solutions demonstrated only mild antibacterial effects, with no significant inhibition observed at lower concentrations (1–6 µL). The antibacterial efficacy of AgNPs was comparable to that of standard antibiotics, such as Azithromycin for Gram-positive bacteria and Ciprofloxacin for Gram-negative bacteria, suggesting their potential as effective antimicrobial agents. The antibacterial activity of the synthesized nanoparticles and the crude flavonoid extract highlights the promising use of Bombax ceiba flower extract in the green synthesis of metal nanoparticles with potential biomedical applications.

A medicinal plant is any plant that in one or more of its organs contains substances that can be used by it or their constituent for therapeutic purposes. The present work was done to evaluate pharmacognostic, fluorescence, proximate and phytochemical analysis of ethanolic extracts of Cistanche tubulosa (Orobanchaceae) along with antimicrobial activity. Antimicrobial activity against four bacterial strains S. aureus, E. coli, P. aeruginosa, S. typhi along with five fungal strains such as F. oxyfurum, P. notatum, Candida albicans, A. fumigatus, and A. niger evaluate using agar well diffusion method. The powder drug study of various tissues of plants revealed higher concentrations (20.29 mg/l) of essential macro and micronutrients. Fluorescence analysis of the stem powdered with various chemical reagents showed different colors. Proximate analysis showed the presence of crude substances such as proteins (8.5 %), fat (1.5 %), fibres (6.6 %), carbohydrates (73.87 %), moisture contents (3.23 %) and ash contents (6.3 %) respectively. Phytochemical screening revealed the presence of carbohydrates, proteins and dozen other important secondary metabolites. The presence of these bioactive constituents associated with the antimicrobial activity of S. aureus showed the maximum zone of inhibition (15.1 ± 3.7 mm), while in antifungal activity C. albicans showed the highest zone of inhibition (11.0 ± 3.15 mm). The pharmacognostic study, fluorescence analysis and antimicrobial activity are helpful in the standardization of the drug establishing a good support for the use of C. tubulosa in traditional medicine.

Human orthopneumovirus (HOPV) is the major viral pathogen responsible for lower respiratory tract infections (LRTIs) in infants and young children in Riyadh, Saudi Arabia. Yet, predominant HOPV subtypes circulating in this region and their molecular and epidemiological characteristics are not fully ascertained. A total of 300 clinical samples involving nasopharyngeal aspirates (NPAs), throat swabs, and sputum were collected during winter seasons of 2019/2020 and 2021/2022 for HOPV subtyping and genotyping. Of the 300 samples, HOPV was identified in 55 samples (18.3%) with a distinct predominance of type A viruses (81.8%) compared to type B viruses (18.2%). Importantly, the ON1 strain of HOPV-A and BA-IX strain of HOPV-B groups were found to be responsible for all the infections. Sequence analysis revealed a duplication region within 2nd HVR of G protein gene of ON1 and BA-IX strains. This nucleotide duplication exerted a profound effect on protein length and affinity towards cell receptors. Further, these modifications may aid the HOPV in immune evasion and recurrent infections. Data from this study showed that ON-1 genotype of HOPV-A and BA-IX genotype of HOPV-B were dominant in Riyadh, Saudi Arabia. Further, a duplication of sequence within 2nd HVR of G protein gene was found.

Currently, the standard assay employed to diagnose human orthopneumovirus infection is real-time reverse transcriptase PCR assay (rRT-PCR), a costly and time-consuming procedure that requires the manipulation of infectious viruses. In addition to RT-PCR, serological tests can complement the molecular diagnostic methods and have proven to be important tools in sero-surveillance. In this study, we report the development, optimization, and validation of a novel and rapid in-house diagnostic ELISA kit to detect human orthopneumovirus in clinical samples. We developed three sensitive ELISA formats through the immunization of rats with novel recombinant pPOE-F or pPOE-TF vectors. The two vectors expressed either the full-length (pPOE-F) or the truncated form (pPOE-TF) of the fusion (F) protein. The developed ELISA kits were optimized for coating buffer, capture antibody, blocking buffer, sample antigen, detection antibodies, and peroxidase-conjugated antibody, and validated using 75 rRT-PCR-confirmed nasopharyngeal aspirate (NPA) human orthopneumovirus samples and 25 negative samples collected from hospitalized children during different epidemic seasons between 2014 and 2017. Our results indicate that rats immunized with pPOE-F or pPOE-TF showed significant induction of high levels of MPAs. Validation of the ELISA method was compared to the rRT-PCR and the sensitivity hierarchy of these developed ELISA assays was considered from highest to lowest: indirect competitive inhibition ELISA (93.3%) > indirect antigen-capture ELISA (90.6%) > direct antigen-capture ELISA (86.6%). The development of the rapid in-house diagnostic ELISA kits described in this study demonstrates that a specific, rapid and sensitive test for human orthopneumovirus antigens could be successfully applied to samples collected from hospitalized children during different epidemics and can help in the efficient diagnosis of respiratory syncytial viral infections.