Essential oil composition of Origanum vulgare and its application in substitution of synthetic chemical additives

In this work, the gas  chromatography-mass spectrometry (GC/MS) analysis of the essential oil of Origanum vulgare. L. obtained by hydrodistylation was warried out and it allowed to identify 98.1% of its constituents. The main components are carvacrol (47.6%), thymol (16.6%), p-cymene (13.5%) andγ-terpinene (11.2%). The chemical components of the essence are distributed over five biochemical classes represented mainly by monoterpene phenols and monoterpene carbides. The extraction gave a yield of oil 2.8%. The minimum inhibitory concentration (MIC) of this oil was determined against food spoilage bacteria and pathogenic bacteria belonging to the genus Staphylococcus tested in vitro. This study aims to enhance the value of oregano essential oil by determining its chemical composition on the one hand, and by its application as a natural antibacterial preservative in substitution of synthetic chemical additives on the other hand. The sample was incorporated into a sensitive food matrix exposed to bacterial contamination: white meat. The bacteriostatic/bactericidal power of this bioactive extract was determined by a significant reduction in the number of bacteria and a clear increase in shelf life. Thus, it is possible to propose the use of this aromatic essence as a source of natural preservative

MOLECULAR CHARACTERIZATION OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS ISOLATED FROM CLINICAL CASES IN EAST ALGERIA

Objective: The purpose of this study is to investigate the methicillin resistance gene, and some virulence factors in methicillin-resistant Staphylococcus aureus (MRSA) isolates by polymerase chain reaction (PCR).Methods: This study has included 12 MRSA isolates. All isolates were previously identified as S. aureus by a standard microbiological procedure, and a detection of methicillin resistance was realized by phenotypic methods. Following genomic DNA extraction, the presence of gyrA, mecA, lukPV, and tst genes was analyzed by duplex PCR. All retained S. aureus species have been found to contain gyrA gene.Results: Ten stains have been found to harbor mecA gene indicating it's responsibility for methicillin resistance in those strains. Among the 12 strains, six of which were found to be Panton-Valentine leukocidine positive while none of which has tst gene encoding the toxic shock syndrome toxin.Conclusion: The pathogenesis of MRSA infections is related to the expression of a wide variety of virulence factors.Keywords: Methicillin-resistant Staphylococcus aureus, Panton-Valentine leukocidine, Toxic shock syndrome toxin 1, Multidrug resistance, mecA

Surface performances of PVD ZrN coatings in biological environments

Zirconium nitride (ZrN) thin films were deposited by reactive RF magnetron sputtering on Ti-6Al-4V and Si (100) substrates for potential use in biomedical applications. The tribological behaviour was evaluated against bovine bone in dry condition using a pin-on-disc apparatus. Abrasion is the primary wear mechanism observed in ZrN/bone contact. The corrosion properties were determined through two electrochemical techniques: potentiodynamic polarization and electrochemical impedance spectroscopy. The coatings with reduced oxygen content provided: (i) good resistance against corrosion when exposed to physiological solution and (ii) better anti-bioadhesion against Staphylococcus aureus bacteria.Bourse PNE Ministère algérie

Comparative Study of the Bacteriological Activity of Zinc Oxide and Copper Oxide Nanoparticles

Interest in nanomaterials, especially metal oxides, in the fight against resistant and constantly changing bacterial strains, is more and more expressed. Their very high reactivity, resulting from their large surface area, promoted them to the rank of potential successors of antibiotics

Genome sequence and description of Mannheimia massilioguelmaensis sp. nov.

International audienceStrain MG13 T sp. nov. is the type strain of Mannheimia massilioguelmaensis, a new species within the genus Mannheimia. This strain was isolated from the exudate of a skin lesion of an Algerian man. Mannheimia massilioguelmaensis is a Gram-negative, facultative anaerobic rod, member of the family Pasteurellaceae. Here we describe this organism, together with the complete genome sequence and annotation. The 2 186 813 bp long genome contains 2048 protein-coding and 55 RNA genes, including eight rRNA genes

Efficient Synthesis, Characterization, and Antibacterial Activity of Novel <i>N</i>-Acylsulfonamides and Sulfonylureas

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First Detection of VIM-4-Producing Pseudomonas aeruginosa and OXA-48-Producing Klebsiella pneumoniae in Northeastern (Annaba, Skikda) Algeria

International audiencePurpose: The aim of the study was to investigate the prevalence and molecular support of carbapenem resistance in gram-negative bacilli clinical isolates collected between March 2013 and March 2015 in three cities (Annaba, Skikda, and Guelma) in northeastern Algeria. Results: One hundred eighty-six isolates were identified as Enterobacteriaceae (161), Pseudomonas aeruginosa (18), and Acinetobacter baumannii (7). Thirty-six of 186 (19.3%) were resistant to carbapenems. Among them, 11 harbored carbapenemase genes, including bla(OXA-48) (2 Klebsiella pneumoniae), bla(VIM-4) (2 P. aeruginosa), bla(NDM-1) (2 A. baumannii), and bla(OXA-23) (5 A. baumannii). In addition, other -lactamases were detected: bla(CTX-M-(15/66/139)), bla(SHV-(28/85/1/133)), and bla(TEM-1). All imipenem-resistant P. aeruginosa displayed OprD mutations. Multilocus sequence typing demonstrated the presence of ST 404 and ST 219 in K. pneumoniae, ST 2 and ST 85 in A. baumannii, and ST (244, 1076, 241, 227, and 233) in P. aeruginosa.Conclusion: In this study, we report the first detection of P. aeruginosa ST 1076 harboring the bla(VIM-4) gene in African countries in two cities (Annaba and Skikda) in northeastern Algeria. Additionally, we report the first detection of bla(OXA-48) in K. pneumoniae ST 404 and ST 219 in Algerian cities (Annaba and Skikda)