Deciphering the complex three-way interaction between the non-integrin laminin receptor, galectin-3 and Neisseria meningitidis

The non-integrin laminin receptor (LAMR1/RPSA) and galectin-3 (Gal-3) are multi-functional host molecules with roles in diverse pathological processes, particularly of infectious or oncogenic origins. Using bimolecular fluorescence complementation and confocal imaging, we demonstrate that the two proteins homo- and heterodimerize, and that each isotype forms a distinct cell surface population. We present evidence that the 37 kDa form of LAMR1 (37LRP) is the precursor of the previously described 67 kDa laminin receptor (67LR), whereas the heterodimer represents an entity that is distinct from this molecule. Site-directed mutagenesis confirmed that the single cysteine (C173) of Gal-3 or lysine (K166) of LAMR1 are critical for heterodimerization. Recombinant Gal-3, expressed in normally Gal-3-deficient N2a cells, dimerized with endogenous LAMR1 and led to a significantly increased number of internalized bacteria (Neisseria meningitidis), confirming the role of Gal-3 in bacterial invasion. Contact-dependent cross-linking determined that, in common with LAMR1, Gal-3 binds the meningococcal secretin PilQ, in addition to the major pilin PilE. This study adds significant new mechanistic insights into the bacterial–host cell interaction by clarifying the nature, role and bacterial ligands of LAMR1 and Gal-3 isotypes during colonization

An evaluation of E. coli in urinary tract infection in emergency department at KAMC in Riyadh, Saudi Arabia: retrospective study

Abstract Background Urinary tract infection (UTIS) is a common infectious disease in which level of antimicrobial resistance are alarming worldwide. Therefore, this study aims to describe the prevalence and the resistance pattern of the main bacteria responsible for UTIS Escherichia coli (E. coli). Methods Retrospective chart review for patients admitted to emergency department and diagnosed with UTIS at KAMC, in Riyadh, Saudi Arabia between January to March 2008 was performed. Antimicrobial susceptibility to ampicillin, augmentin (amoxicillin/clavulanate), cefazolin, co-trimoxazole (sulfamethoxazole/trimethoprim), ciprofloxacin, and nitrofurantoin, and cefpodoxime was determined for 101 E. coli urinary isolates. Results Escherichia coli was the most prevalent pathogen contributing to UTIS representing 93.55, 60.24, and 45.83% of all pathogen isolated from urine culture of pediatric, adult, and elderly, respectively. High rates of resistance to ampicillin (82.76, 58, and 63.64%) and co-trimoxazole (51.72, 42, and 59.09%), among E. coli isolated from pediatric, adult and elderly respectively. Nitrofurantoin was the most active agent, followed by ciprofloxacin, augmentin and cefazolin. 22.77% of E. coli isolates exhibited multiple drug resistance (MDR). Among 66 and 49 isolates resistant to ampicillin and co-trimoxazole, respectively, 34.84 and 42.85% were MDR. In contrast, all isolates resistant to augmentin and nitrofurantoin were MRD, while 72.7 and 82.4% of isolates resistant to ciprofloxacin and cefazolin were MDR. Conclusions High resistance was observed to ampicillin and co-trimoxazole which commonly used as empirical treatments for UTIS, limiting their clinical use. This necessitates continuous surveillance for resistance pattern of uropathogens against antibiotics

Formulation and evaluation of docetaxel nanosuspensions: In-vitro evaluation and cytotoxicity

Objective: The aim of the present study was to formulate the anticancer drug; docetaxel (DOX) as nanoparticles to enhance its biological activity. Methodology: Solvent precipitation method was used to prepare DOX-loaded nanoparticles and was stabilized by different concentrations of hydroxypropyl methylcellulose (HPMC, E5) and sodium deoxycholate (SDC). Results: The results showed that the particle size of the prepared DOX nanoparticles stabilized by SDC was small in comparison to those stabilized by the corresponding HPMC concentrations. The smallest particle size (83.97 nm) was obtained by using SDC as stabilizer at 5% level with zeta potential of −13.6 mV. It was concluded that increasing the stabilizer concentration resulted in increase in both initial and overall cumulative drug release. The release rate in case of nanoparticles stabilized by 5% SDC was 33% and 87% after 1 and 24 h respectively. The results showed that a significant reduction in the viability of FRO cells was observed at all tested time intervals in case of nanoparticles stabilized by 5% SDC at concentrations of 100 and 1000 μM/ml. In contrast, no signs of cytotoxicity was observed for nanoparticles stabilized by 5% HPMC at 10 and 100 μM/ml concentrations. Keywords: Docetaxel, Nanoparticles, Stabilizers, In-vitro release, Cytotoxicit

Detection of some haemorrhagic fever viruses in wild shrews collected from different habitats in Saudi Arabia : first record in the Middle East

Shrews (family Soricidae) are tiny mole-shaped mammals belong to the order Eulipotyphla. The main objective of this study is to screen wild specimens of shrews for specific RNA viruses cause hemorrhagic fevers. Wild specimens of shrews were collected from rural areas in Kingdom of Saudi Arabia. Collection of shrews were carried out from the traps then identified using the classical morphological keys. Specimens were dissected then extraction of single stranded RNA of shrews was performed from internal organs including lungs, livers, kidneys, and stomach using QiagenRNeasy Mini Kit. RT-PCR was utilized for screening of Crimean- Congo hemorrhagic fever virus (CCHFV), Rift Valley Fever Virus (RVFV), and Chikengunya virus (CHIKV), and Sindbis virus (SINV). The results revealed SINV, CHIKV, and CCHFV were all found in the internal viscera of shrews in four different groups. This demonstrated that the viruses were propagating and spreading throughout the tissues of the shrews. Conclusions: Depending to our knowledge results of this study constitute first record in Kingdom Saudi Arabia and significantly highlight some of the neglected wild reservoirs of arboviruses; therefore future studies should focus on evaluating other hosts, including bats.Correction in: Journal of King Saud University Science, Volume 34, Issue 3, Article Number 101862, DOI 10.1016/j.jksus.2022.101862</p

Anti-quorum sensing activity of poly-amidoamine dendrimer generation 5 dendrimer loaded kinase inhibitor peptide against methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is a significant concern in both healthcare and community settings, as it causes numerous infections worldwide with high morbidity and mortality rates. One promising strategy is to target the quorum sensing (QS) system of MRSA using a dendrimer loaded with kinase inhibitor peptide. The present investigation has formulated a poly-amidoamine dendrimer (PAMAM) G5 dendrimer that is loaded with Quorum Quencher (QQ) peptide, which functions as a histidine kinase inhibitor. The particle average size of the formulated G5-QQ3 complex was determined to be 276 nm, and polydispersity index values of 0.33. The MIC50 for the formulated nanoparticles was 18 μM as demonstrated by a growth assay. Furthermore, the G5-QQ3 complex was able to inhibit the hemolysis activity of the MRSA with a concentration of 10 μM, and for Staphylococcus aureus was 3 μM. The G5-QQ3 complex possesses the ability to inhibit, penetrate, and eradicate biofilm in MRSA, Staphylococcus aureus, and different agr mutants with inhibition percentages ranging from 60 to 72%. Furthermore, live/dead viability assay confirmed the ability of the formulated nanoparticles to effectively kill all strains within the biofilm structure as evidenced by a confocal microscope, and the cytotoxicity of the G5-QQ3 complex was dose-dependent (p < 0.05). against RAW 264.7 cells. In general, the study confirmed that encapsulating QQ3 peptide within PAMAM G5 dendrimer results in a potent anti-virulence and anti-bacterial action and suggests a synergistic effect. The findings of this study have significant implications for the development of new treatments for MRSA infections, which are a major public health concern

Preparation and characterization of Meta-bromo-thiolactone calcium alginate nanoparticles

Recently, the focus has been shifting toward Quorum sensing inhibitors which reduce Pseudomonas aeruginosa virulence factors, alleviating infections. In this work, me-ta-bromo-thiolactone (mBTL), a potent quorum and virulence inhibitor for the Pseudomonas aeruginosa strains, were formulated in calcium alginate nanoparticles (CANPs). Alginate is used as nutrients and as backbone virulence aspect for Pseudomonas and therefore was chosen. mBTL-loaded-CANPs were characterized for particle size, polydispersity index, zeta potential, morphology visualized by Transmission Electron Microscopy (TEM) and drug release profile. Chemical and physical analysis of formulated mBTL-loaded-CANPs were evaluated using Fourier transform infrared Spectroscopy (FTIR) and differential scanning calorimetry (DSC) and Physical stability of mBTL-loaded-CANPs assessed at various temperature 25 ± 1 °C, 4 ± 0.5 °C and −30° ± 1 °C over a period of 4 and 9 months. Synthesized CANPs showed nano-size particles ranging from 140 to 200 nm with spherical particles for plain CANPS and irregular shape for mBTL-loaded-CANPs with a sustainable release profile over 48hrs. FTIR showed stable structure of loaded-mBTL and DSC displayed no interaction between mBTL and polymer. State of released mBTL from CANPs kept at 25 °C, 4 °C and −30 °C over 4 and 9 months showed stable formula at room temperature which kept as a goal of nanoparticles storage. The findings of this study revealed successful preparation of mBTL-loaded-CANPs

Prevalence and identification of arthropod-transmitted viruses in Kassala state, Eastern Sudan

Vector-borne diseases are responsible for more than 20% of the infectious diseases worldwide. The prevalence of arboviruses transmit diseases to humans in Sudan has not been investigated. Mosquito-borne viral diseases increase globally incidence, including the Sudan. Frequent unknown fever outbreaks have been reported in eastern region, Sudan. However, diagnosis was based exclusively on clinical signs and symptoms without confirmatory laboratory investigations. However, for accurate detection of these viruses in outbreaks, molecular technique is considered. The objective of this study was to determine the prevalence of six arboviruses in the Kassala state of east Sudan during unknown fever outbreak. A cross sectional hospital-based study was conducted in the Kassala, Teaching Hospital. Blood samples from 119 patients suffering from unknown fever were used for screening of six arboviruses, hepatitis E virus and malarial using molecular techniques and serology. The overall arboviruses seroprevelance was 61.3% (73/119). The highest positivity rate was 73.1% (52/73) chikungunya virus; 29 males and 20 females patients were chikungunya positive. Other arboviruses were circulating in low rate 20.5% (15/73), and 6.8% (5/73) for sindbis and rift valley fever viruses respectively. Hepatitis E virus was negative in all cases and malaria positivity rate 13.4% (16/119). The prevalence of arboviruses among unknown fever patients present to Kassala teaching hospital of eastern region in Sudan is significantly high (61.3%). The chikungunya virus is the predominant causative agent of arboviruses. Molecular techniques such as PCR are important for accurate and rapid diagnosis of this viral outbreak

Retinal Delivery of the Protein Kinase C-β Inhibitor Ruboxistaurin Using Non-Invasive Nanoparticles of Polyamidoamine Dendrimers

Ruboxistaurin (RBX) is an anti-vascular endothelial growth factor (anti-VEGF) agent that is used in the treatment of diabetic retinopathy and is mainly given intravitreally. To provide a safe and effective method for RBX administration, this study was designed to develop RBX nanoparticles using polyamidoamine (PAMAM) dendrimer generation 5 for the treatment of diabetic retinopathy. Drug loading efficiency, and in vitro release of proposed complexes of RBX: PAMAM dendrimers were determined and the complexation ratio that showed the highest possible loading efficiency was selected. The drug loading efficiency (%) of 1:1, 2.5:1, and 5:1 complexes was 89.2%, 96.4%, and 97.6%, respectively. Loading capacities of 1:1, 2.5:1, and 5:1 complexes were 1.6%, 4.0%, and 7.2% respectively. In comparison, the 5:1 complex showed the best results in the aforementioned measurements. The in vitro release studies showed that in 8 h, the RBX release from 1:1, 2.5:1, and 5:1 complexes was 37.5%, 35.9%, and 77.0%, respectively. In particular, 5:1 complex showed the highest drug release. In addition, particle size measurements showed that the diameter of empty PAMAM dendrimers was 214.9 ± 8.5 nm, whereas the diameters of loaded PAMAM dendrimers in 1:1, 2.5:1, 5:1 complexes were found to be 461.0 ± 6.4, 482.4 ± 12.5, and 420.0 ± 7.1 nm, respectively. Polydispersity index (PDI) showed that there were no significant changes in the PDI between the free and loaded PAMAM dendrimers. The zeta potential measurements showed that the free and loaded nanoparticles possessed neutral charges due to the presence of anionic and cationic terminal structures. Furthermore, the safety of this formulation was apparent on the viability of the MIO-M1 cell lines. This nanoformulation will improve the therapeutic outcomes of anti-VEGF therapy and the bioavailability of RBX to prevent vision loss in patients with diabetic retinopathy

Capsule Independent Antimicrobial Activity Induced by Nanochitosan against Streptococcus pneumoniae

BACKGROUND: Streptococcus pneumoniae remains a major cause of community-acquired pneumonia, meningitis, and other diseases, contributing significantly to high morbidity and mortality worldwide. Although it responds to antibiotics, their use is becoming limited due to the rise in antibiotic resistance, which necessitates the development of new therapeutics. Nanotechnology is used to counteract antimicrobial resistance. In this regard, polymeric nanoparticles (NPs) made of natural, biodegradable, biocompatible, and cationic polymers such as Chitosan (CNPs) exhibit wide-spectrum antimicrobial activity. Therefore, this study aimed to prepare CNPs, characterize their physiochemical characteristics: particle size (PZ), polydispersity index (PDI), and zeta potential (ZP), and investigate their antimicrobial activity against Streptococcus pneumoniae TIGR4 (virulent serotype 4) and its capsular mutant (∆cps).METHODS: CNPs were prepared at 1, 2.5, and 5 mg/mL concentrations using the ion gelation method. Then, PZ, PDI, and ZP were characterized using a Zetasizer. Transmission electron microscopy (TEM) was used to visualize the CNP's morphology. Broth and agar dilution methods were used to assess their antimicrobial activity. Cytotoxicity of prepared NPs on A549 cells and their effect on pneumococcal hemolysis were also investigated.RESULTS: Spherical CNPs were produced with PZ ranging from 133.3 nm ± 0.57 to 423 nm ± 12.93 PDI < 0.35, and ZP from 19 ± 0.115 to 27 ± 0.819. The prepared CNPs exhibited antibacterial activity against TIGR4 and its capsule mutant with a minimum inhibitory concentration (MIC90) of 0.5 to 2.5 mg/mL in a non-acidic environment. The hemolysis assay results revealed that CNPs reduced bacterial hemolysis in a concentration-dependent manner. Their mammalian cytotoxicity results indicated that CNPs formed from low concentrations of Chitosan (Cs) were cytocompatible.CONCLUSION: Nanochitosan particles showed anti-pneumococcal activity regardless of the presence of capsules. They resulted in a concentration-dependent reduction in bacterial hemolysis and were cytocompatible at a lower concentration of Cs. These findings highlight the potential of CNPs in the treatment of pneumococcal diseases

First record of West Nile Virus detection inside wild mosquitoes in Khartoum capital of Sudan using PCR

This study aimed to explore the presence of West Nile Virus (WNV) inside four species of mosquitoes: Culex univittatus (Theobald), Culex quinquefasciatus (Say) Aedes vittatus (Bigot) and Aedes vexans (Meigen). Adult wild mosquitoes were collected from different sites: Soba West, Hellat Kuku, Shambat, and Khartoum North Central Live Stock Market (KCLM). Surveys were carried out at Khartoum State during two phases: pre to the rainy season and post to the rainy season. Mosquito specimens were identified using classical keys then preserved at −80 °C freezer for two weeks till the virus examination using polymerase chain reaction (PCR) were carried out. WNV has been detected inside the three species of mosquitoes: A. vexans, C. univittatus, and C. quinquefasciatus. The species were collected from Hellat Kuku, (Shambat and Hellat Kuku), and (Shambat and KCLM) respectively. Two species of mosquitoes were positive for the virus: C. quinquefasciatus and C. univittatus. Positive results for the virus during the first phase of the study; males of C. quinquefasciatus and C. univittatus collected during the second phase of the study were also tested for the existence of the virus and they were positive. For our knowledge this study represents first record of WNV inside wild mosquitoes in Sudan. PCR technique provided reliable information because specific primer-probe sets were used for the detection of the virus. Extra studies are required to incriminate these species of mosquitoes as potential vectors of WNV