Oriental Journal of Chemistry is a peer reviewed quarterly research journal of pure and applied chemistry. It publishes standard research papers in almost all thrust areas of current chemistry of academic and commercial importance. It provides a platform for rapid publication of quality research papers, reviews and chemistry letters. Oriental Journal of Chemistry is abstracted and indexed in almost all reputed National and International agencies.

Background and Aim. Staphylococcal food poisoning is caused by the consumption of food contaminated with Staphylococcus aureus and represents a global public health concern. Food products of animal origin can serve as reservoirs for multi-drug resistant strains of S. aureus. This study aimed to characterize the microbiological and molecular genetic properties of S. aureus isolated from raw horse meat. Materials and Methods. Species identification of S. aureus was performed using 16S rRNA gene analysis and matrix assisted laser desorption/ionization time-of-flight mass spectrometry. The sensitivity of the isolate to antibiotics was investigated using the disc diffusion method. Genetic determinants of resistance were identified using whole genome sequencing. High-throughput sequencing was performed on an Illumina MiSeq platform. DNA quantity was assessed spectrophotometrically, and quality was evaluated by electrophoresis on a 1% agarose gel. Genome assemblies based on short reads were obtained using SPAdes v. 4.0.0. Assembly quality assessment, organism verification, and initial annotation were performed using FastQC v.0.11.9. Antibiotic resistance genes were identified using the CARD and PATRIC databases. Results. The S. aureus 76_KZ strain was isolated from a raw horse meat sample. Morphologically, it is a Gram-positive coccus arranged in irregular clusters resembling grape bunches. The identified antibiotic resistance profile of S. aureus 76_KZ characterizes this strain as a multidrug resistant isolate with sensitivity to a limited spectrum of antibacterial drugs. This study presents the results of wholegenome sequencing of S. aureus isolated from raw horse meat in the Republic of Kazakhstan. The sequencing yielded a genome coverage of 173×. The sequenced genome of the S. aureus 76_KZ isolate, consisting of 2.616.354 bp, has been deposited in the GenBank genetic database under accession number JBNBZR000000000.1. Conclusion. The whole-genome data obtained for S. aureus 76_KZ enable the assessment of the isolate's resistance to antimicrobial drugs and facilitate the identification of genetic features relevant to epidemiological typing.

This study explores an adaptation mechanism of Bacteroides fragilis to subinhibitory concentrations of meropenem, characterized by an alteration in the production of membrane vesicles (MVs) and modulation of the host inflammatory response. Using a rat model of infection, we demonstrated a significant increase in the size of MVs accompanied by a nonsignificant increase in their number in the meropenem-treated group compared to the infected control. Both infected groups showed significantly altered hematological parameters and shifts in monocyte on day 8 (average increase of 21.5 %). At the same time, significant changes in neutrophils (decrease by 26 %) and eosinophils (increase by 3 %) were observed only in the infected group but not in the infected meropenem-treated group. On day 16, increased macrophage activation, neovascularization, and fibrosis were observed in the tissues of the antibiotic-treated group. Immunological profile analysis revealed a slight increase in the levels of pro-inflammatory cytokines (IL-5, IL-6, IFN-gamma and G-CSF) on day 8 of the experiment, followed by a sharp decrease on day 16 in both infected groups compared to the negative control. At the same time, network analysis of correlations between these immunological factors showed complex changes in response to subinhibitory concentrations of meropenem. The bacterial load did not differ between the infected groups on days 8 and 16, but only in the meropenem-free group a significant decrease in the number of bacteria was observed on day 16 in all samples. These findings suggest that subinhibitory antibiotic concentrations can influence the pathophysiological progression of B. fragilis infection, modulating both the bacterial response and the host immune reaction, potentially leading to a more complex and chronic disease course.

Antibiotic resistance is a major global health concern, and inappropriate antibiotic use contributes significantly to the development of resistance in pathogens. Bacteroides fragilis, an anaerobic bacterium, is commonly treated with β-lactam antibiotics like meropenem. B. fragilis possesses various antibiotic resistance mechanisms, including enzymatic modification of antibiotics, efflux systems, and reduction of cell membrane permeability. The primary mechanism of carbapenem resistance in B. fragilis is linked to the production of a metallo-β-lactamase encoded by the cfiA gene. However, this gene is frequently inactive and requires activation by insertion elements. The study aimed to explore the expression of specific genes in B. fragilis associated with different metabolic pathways in response to exposure to sub-inhibitory concentrations of meropenem. The study used B. fragilis strain BFR KZ01, obtained from a patient with appendicitis and peritonitis. Serial exposure to meropenem was conducted, and gene expression was analyzed using quantitative RT-PCR. Significant and long-lasting alterations in gene expression patterns were observed in B. fragilis following exposure to meropenem, even after removal of the antibiotic. Genes such as cfiA, oxyR, and Ddl showed heightened expression levels even after discontinuation of meropenem. The study discussed the implications of gene expression changes induced by meropenem exposure, highlighting the role of oxidative stress response (oxyR), D-Ala-D-Ala ligase (Ddl), and carbapenemase (cfiA) genes in antibiotic resistance mechanisms. The study concluded that exposure to meropenem induced lasting alterations in gene expression in B. fragilis, contributing to antibiotic resistance. Understanding these mechanisms is crucial for developing strategies to combat antibiotic resistance.

Background/Objectives: Brain arteriovenous malformations (bAVMs) are rare vascular anomalies characterized by direct connections between arteries and veins, bypassing the capillary network. This study aimed to identify potential genetic factors contributing to the development of sporadic bAVMs. Methods: Three patients (AVM1–3) from Kazakhstan who underwent microsurgical resection at the National Centre for Neurosurgery (NCN) in Astana, Kazakhstan, were analyzed. Brain AVMs were diagnosed using magnetic resonance imaging (MRI). Genomic DNA was isolated from whole venous blood samples, and whole-exome sequencing was performed on the NovaSeq 6000 platform (Illumina). Variants were filtered according to standard bioinformatics protocols, and candidate gene prioritization was conducted using the ToppGene tool. Results: In silico analysis further revealed candidate genes likely associated with lesion development, including COL3A1, CTNNB1, LAMA1, NPHP3, SLIT2, SLIT3, SMO, MAPK3, LRRK2, TTN, ERBB2, PARD3, and OBSL1. It is essential to focus on the genetic variants affecting the following prioritized genes: ERBB2, SLIT3, SMO, MAPK3, and TTN. Mutations in these genes were predicted to be “damaging”. Most of these genes are involved in signaling pathways that control vasculogenesis and angiogenesis. Conclusions: Defects in genes associated with ciliary structure and function may be critical to the pathogenesis of brain AVMs. These findings provide valuable insights into the molecular underpinnings of bAVM development, emphasizing key biological pathways and potential candidate genes. Further research is needed to establish robust correlations between specific genetic mutations and clinical phenotypes, which could ultimately inform the development of improved diagnostic, therapeutic, and prognostic approaches.

Antibiotic concentrations at clinical breakpoint levels can influence bacterial physiology and virulence responses, yet their effects on outer membrane vesicle (OMV) production in anaerobic pathogens remain understudied. This study examined how breakpoint meropenem concentrations affect the ultrastructure, inflammatory responses, and OMV production of Bft + enterotoxigenic Bacteroides fragilis (ETBF) in a rat intra-abdominal infection model. Forty male Wistar rats were divided into negative control (n = 8), positive control (B. fragilis infection, n = 16), and experimental group (B. fragilis infection + meropenem at clinical breakpoint concentration 1.0 mg/L for 8 days, n = 16). Transmission electron microscopy, morphometric vesicle analysis, hematological studies, and qRT-PCR cytokine expression analysis were performed on days 8 and 16. Both B. fragilis infection groups showed systemic inflammation with critical hematocrit reduction to 27–28% compared to negative control (p ≤ 0.001). Breakpoint meropenem did not improve infection outcomes; bacterial load showed no significant differences, and OMV production demonstrated only a non-significant trend toward increase. However, the experimental group exhibited inflammation progression with significant elevation in IL-1α, IL-1β, and TNF-α expression by day 16 (p ≤ 0.05). Notably, OMV size distribution changed dramatically under breakpoint treatment, shifting toward significantly smaller vesicles (< 90 nm; Cliff’s δ = −0.49, p ≤ 0.0001). The study demonstrates that breakpoint meropenem concentration triggers sustained stress response in enterotoxigenic B. fragilis, producing pronounced changes in OMV profile and suggesting a mechanism facilitating antibiotic resistance development.