Global genomic epidemiology of chromosomally mediated non-enzymatic carbapenem resistance in Acinetobacter baumannii: on the way to predict and modify resistance

IntroductionAlthough carbapenemases are frequently reported in resistant A. baumannii clinical isolates, other chromosomally mediated elements of resistance that are considered essential are frequently underestimated. Having a wide substrate range, multidrug efflux pumps frequently underlie antibiotic treatment failure. Recognizing and exploiting variations in multidrug efflux pumps and penicillin-binding proteins (PBPs) is an essential approach in new antibiotic drug discovery and engineering to meet the growing challenge of multidrug-resistant Gram-negative bacteria.MethodsA total of 980 whole genome sequences of A. baumannii were analyzed. Nucleotide sequences for the genes studied were queried against a custom database of FASTA sequences using the Bacterial and Viral Bioinformatics Resource Center (BV-BRC) system. The correlation between different variants and carbapenem Minimum Inhibitory Concentrations (MICs) was studied. PROVEAN and I-Mutant predictor suites were used to predict the effect of the studied amino acid substitutions on protein function and protein stability. Both PsiPred and FUpred were used for domain and secondary structure prediction. Phylogenetic reconstruction was performed using SANS serif and then visualized using iTOL and Phandango.ResultsExhibiting the highest detection rate, AdeB codes for an important efflux-pump structural protein. T48V, T584I, and P660Q were important variants identified in the AdeB-predicted multidrug efflux transporter pore domains. These can act as probable targets for designing new efflux-pump inhibitors. Each of AdeC Q239L and AdeS D167N can also act as probable targets for restoring carbapenem susceptibility. Membrane proteins appear to have lower predictive potential than efflux pump-related changes. OprB and OprD changes show a greater effect than OmpA, OmpW, Omp33, and CarO changes on carbapenem susceptibility. Functional and statistical evidence make the variants T636A and S382N at PBP1a good markers for imipenem susceptibility and potential important drug targets that can modify imipenem resistance. In addition, PBP3_370, PBP1a_T636A, and PBP1a_S382N may act as potential drug targets that can be exploited to counteract imipenem resistance.ConclusionThe study presents a comprehensive epidemiologic and statistical analysis of potential membrane proteins and efflux-pump variants related to carbapenem susceptibility in A. baumannii, shedding light on their clinical utility as diagnostic markers and treatment modification targets for more focused studies of candidate elements

Nogo receptor expression in microglia/macrophages during experimental autoimmune encephalomyelitis progression

Myelin-associated inhibitory factors within the central nervous system (CNS) are considered to be one of the main obstacles for axonal regeneration following disease or injury. The nogo receptor 1 (NgR1) has been well documented to play a key role in limiting axonal regrowth in the injured and diseased mammalian CNS. However, the role of nogo receptor in immune cell activation during CNS inflammation is yet to be mechanistically elucidated. Microglia/macrophages are immune cells that are regarded as pathogenic contributors to inflammatory demyelinating lesions in multiple sclerosis (MS). In this study, the animal model of MS, experimental autoimmune encephalomyelitis (EAE) was induced in ngr1+/+ and ngr1–/– female mice following injection with the myelin oligodendrocyte glycoprotein (MOG35–55) peptide. A fate-map analysis of microglia/macrophages was performed throughout spinal cord sections of EAE-induced mice at clinical scores of 0, 1, 2 and 3, respectively (increasing locomotor disability) from both genotypes, using the CD11b and Iba1 cell markers. Western immunoblotting using lysates from isolated spinal cord microglia/macrophages, along with immunohistochemistry and flow cytometric analysis, was performed to demonstrate the expression of nogo receptor and its two homologs during EAE progression. Myelin protein engulfment during EAE progression in ngr1+/+ and ngr1–/– mice was demonstrated by western immunblotting of lysates from isolated spinal cord microglia/macrophages, detecting levels of Nogo-A and MOG. The numbers of M1 and M2 microglia/macrophage phenotypes present in the spinal cords of EAE-induced ngr1+/+ and ngr1–/– mice, were assessed by flow cytometric analysis using CD38 and Erg-2 markers. A significant difference in microglia/macrophage numbers between ngr1+/+ and ngr1–/– mice was identified during the progression of the clinical symptoms of EAE, in the white versus gray matter regions of the spinal cord. This difference was unrelated to the expression of NgR on these macrophage/microglial cells. We have identified that as EAE progresses, the phagocytic activity of microglia/macrophages with myelin debris, in ngr1–/– mice, was enhanced. Moreover, we show a modulation from a predominant M1-pathogenic to the M2-neurotrophic cell phenotype in the ngr1–/– mice during EAE progression. These findings suggest that CNS-specific macrophages and microglia of ngr1–/– mice may exhibit an enhanced capacity to clear inhibitory molecules that are sequestered in inflammatory lesions

Neutrophilia and its correlation with increased inflammatory response in COVID-19 in diabetic and pre-diabetic patients

Background: Hyperglycemic patients are at a high risk of COVID-19 severity. Neutrophils have been considered critical effector cells in COVID-19 development. Vitamin D deficiency is prevalent in hyperglycemic patients and was found to adversely associate with the neutrophil count. Aim: The goal of this work was to evaluate the characteristics of diabetic and pre-diabetic COVID-19 patients and discovered changes in neutrophils and their correlation, if any, with disease clinical presentation. Patients and Methods: The study included total of (514) Covid-19 positive patients confirmed by PCR and recruited from the Prince Mohammad Bin Abdulaziz Hospital in Riyadh, Saudi Arabia. Patient’s clinical characteristics were collected for all patients. Laboratory tests include HbA1c, neutrophil count, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), ferritin, D- dimer, 25 hydroxy vitamin D (25(OH)D), and folate. Results: The results found that 286 patients (55.6%) were diabetic, 77 patients (15%) were pre-diabetic and 151 (29.4%) were normoglycaemic. A significant difference was exhibited regarding the neutrophil count and inflammatory factors of COVID-19 severity. Furthermore, the neutrophil count was found to be directly correlated with the severity monitoring biochemical markers for Covid-19: CRP, ESR, ferritin, and D-dimer and inversely associated with vitamin D levels in diabetic and pre-diabetic patients. Conclusion: Our findings highlight the change of neutrophils in COVID-19 diabetic and pre-diabetic patients that was found to correlate positively with CRP, ESR, ferritin, and D-dimer, and negatively with 25(OH)D, but their correlation with the clinical presentation of the disease need further large investigations

Enhancing knowledge and practices toward Vitamin D deficiency through implementing awareness programs among medical science female students

Objectives Vitamin D (VD) deficiency has widespread prevalence worldwide. In Saudi Arabia, it is the most common form of public health problem with regard to malnutrition. This is because there is insufficient knowledge about negative VD practices. The current study aimed to evaluate VD deficiency knowledge and practices before and after the implementation of an awareness programme. Methods A quasi-experimental design was used for the study, which was conducted at the College of Applied Medical Science at Al-Baha University. A convenience sample encompassing all the female students in the Public Health Department was used ( n = 83 students). Two tools were used for data collection; the first was an intervention questionnaire to assess the students’ knowledge, and the second was a questionnaire concerned with students’ practices in preventing VD deficiency. Results The mean age of the students was 20.75 ± 7.85 years. Of the study’s subjects, 45.8% suffered from VD deficiency and 72.3% had a family history of VD deficiency. The study showed that there had been significant progress in students’ VD knowledge and behaviours following the programme. While 59% of the students had poor knowledge and 95.2% had unsatisfactory practices pre-intervention, 86.7% and 48.2% showed exemplary knowledge and a positive attitude towards VD, respectively, post-intervention. The scores achieved by the students had significantly changed ( p ≤ .01); compared to the knowledge and practice scores of 24.43 ± 7.21 out of 53 and 24.29 ± 5.23 out of 48, respectively, before the intervention, they were elevated to 46.89 ± 9.93 and 29.39 ± 14.23 following the awareness programme. Conclusion This type of health education programme can raise VD deficiency knowledge and improve practices. This study highlights the importance of holding public health awareness campaigns and recommends the creation of specifically designed booklets and leaflets for medical students and patients/visitors to hospital and public places

Amyloid-beta-dependent phosphorylation of collapsin response mediator protein-2 dissociates kinesin in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by accumulation of amyloid plaques and neurofibrillary tangles. Prior to the development of these characteristic pathological hallmarks of AD, anterograde axonal transport is impaired. However, the key proteins that initiate these intracellular impairments remain elusive. The collapsin response mediator protein-2 (CRMP-2) plays an integral role in kinesin-1-dependent axonal transport and there is evidence that phosphorylation of CRMP-2 releases kinesin-1. Here, we tested the hypothesis that amyloid-beta (Aβ)-dependent phosphorylation of CRMP-2 disrupts its association with the kinesin-1 (an anterograde axonal motor transport protein) in AD. We found that brain sections and lysates from AD patients demonstrated elevated phosphorylation of CRMP-2 at the T555 site. Additionally, in the transgenic Tg2576 mouse model of familial AD (FAD) that exhibits Aβ accumulation in the brain with age, we found substantial co-localization of pT555CRMP-2 and dystrophic neurites. In SH-SY5Y differentiated neuronal cultures, Aβ-dependent phosphorylation of CRMP-2 at the T555 site was also elevated and this reduced the CRMP-2 association with kinesin-1. The overexpression of an unphosphorylatable form of CRMP-2 in neurons promoted the re-establishment of CRMP-2-kinesin association and axon elongation. These data suggest that Aβ-dependent phosphorylation of CRMP-2 at the T555 site may directly impair anterograde axonal transport protein function, leading to neuronal defects