Proteolytic Transformation and Stimulation of SARSCov-2 Spike Protein with Human ACE-2 Receptor

Severe acute respiratory syndrome coronavirus has a great role in causing respiratory illness in humans and has the most important relationship of its spike proteins with host ACE-2 receptors. After entry into the human body, the viral S protein receptor-binding domain binds to human ACE-2 receptor. Two modes explained in this paper of an ACE-2 shedding. The shedding induces the process of viral entry to host cells by binding SARS-CoV-2 proteins. The residues of arginine and lysine in the ACE-2 receptor from 652 to 659 amino acid cleavage by ADAM17 but in TMPRSS2 the residues can be seen on amino acid from 697 to 716. Corona virus genome shows some structural proteins that are responsible for the cellular entry and facilitate the attachment of a virus to the host cell. Virus recognizes the attachment site and binds with it and enter into the cell. Spike protein is split from the cleavage site along its two subunits S1 and S2 then during this process. S2 subunit release RBD (Receptor- Binding Domain) of S1 mediated to the ACE-2. The RBD of S1 consists of 200 amino acid domains. The unknown protein B6ATI which is a neutral amino acid transporter located in ileum is the basic cause for formation of ACE-2 homodimer. In this way S1 domain provides site for another S2 domain. This leads to concealing of the ACE-2 ectodomain cleavage-sites, shedding. It prevents endocytosis of the receptor blocking a major pathway in the viral entry.

A Case Series of Pulmonary Mucormycosis Caused by Rhizopus Microsporus

Mucormycosis is a relatively uncommon but intractable fungal infectious disease. The mortality is very high when it occurs. In this study, we reported a continuous cases of pulmonary mucormycosis in three patients who suffered from chronic kidney disease, history of renal transplantation and multiple myeloma in April 2017, respectively. Cultures were obtained from several specimens (pathological tissue, bronchoalveolar lavage fluid and sputum) and all identified as Rhizopus microsporus by Matrix-Assisted Laser Desorption Ionization Time- Of-Flight (MALDI-TOF) mass spectrometry and ITS DNA sequencing methods. In addition, they all showed susceptibility to amphotericin B and posaconazole. Unfortunately, even through the three patients all treated with amphotericin B and posaconazole, one man still died eventually. Clinicians should keep an eye on patients who are at high risk of acquiring this fatal disease and make early intervention strategies to reduce terrible outcomes.

Characterization and Identification of Plant Growth Promoting Traits of a Rhizobacteria: Pantoea Agglomerans 20-19

Plant Growth Promoting Rhizobacteria (PGPR) are known to influence positively plant growth by various direct or indirect mechanisms. The objective of this study was to characterize and identified a bacterium was isolated from the wheat rhizosphere of an semi arid area Meknes (Morocco). The studied strain possess several PGPR trais such as nitrogen fixation ability, phosphate solubilization, production of auxins and Ammonia production. Based on their 16S rDNA sequences, the strain were identified as Pantoea agglomerans 20- 19. This Pantoea agglomerans 20-19 is capable of IAA, ammonia production, nitrogen fixation and solubilization phosphorus. These results showed that Pantoea agglomerans 20-19 with its PGPR traits could consitute a good biofertilizer in semi arid area.

Antimicrobial Resistant Salmonella Serotypes Circulating in Meat in Senegal

The Presence of antimicrobial-resistant Salmonella in food remains a real threat. The aim of this study was to determine the antimicrobial resistance profiles of Salmonella strains isolated from the most consumed types of meat in Senegal. A total of 337 samples were collected including 247 samples of raw meat and 90 of meat-based ready-made meals. Salmonella strains were isolated according to the French standard EN-ISO-6579 and serotyped according to the KWLM scheme. Antimicrobial susceptibility tests were performed with 16 discs following the agar diffusion method. Our study showed that 37% of the samples carried Salmonella and allowed the isolation of 136 strains of Salmonella. We identified 47 different serotypes including S. Kentucky (11/136: 8%), S. Brancaster (10/136: 7%), S. Chester (10/136: 7%), S. Istanbul (5/136: 4 %), and S. Agona (5/136: 4%) which were respectively the most common. Of the 136 strains, 43 (31.6%) were resistant to at least one antibiotic, of which 15.4% (21/136) were multidrug-resistant. Interestingly, S. Kentucky that was the most common, exhibited also the highest level of resistance, being at least resistant to 8 antibiotics. In conclusion, The increasing resistance and spread of S. Kentucky in meat products demand special monitoring and to be further studied.

Enhanced CAUTI Risk due to Strong Biofilm Forming MDR Bacteria in Indwelling Urinary Catheters

The achievement of modern medicine is due to development and extensive use of indwelling biomedical devices like urinary catheters, heart valves, Vascular bypass grafts, ocular lenses and artificial joints, among others. Untreated nosocomial infections due to urinary catheter- biofilms pose great health risk to patients. This study focuses on the isolation, molecular identification, antibiotic susceptibility profiling and physicochemical characterization of strong biofilm producers from indwelling urinary catheters. Out of 34 isolates 19 strong biofilm producers were segregated using Microtitre plate and Congo red agar methods. Klebsiella pneumoniae, Pseudomonas aeruginosa, Escherichia coli, Morganella morganii and Enterococcus faecalis, which are common causative agents of Catheter-Associated Urinary Tract Infection (CA-UTI) were identified by molecular characterization and phylogenetic analyses. All strong biofilm formers were multi drug resistant by modified Kirby- Bauer method and Multiple Antibiotic Resistance (MAR) index was also calculated Further physicochemical characterization included hydrophobicity and autoaggregation assays. All the strong biofilm producers exhibited multiple antibiotic resistance. More than 60 per cent of the selected strains were strongly hydrophobic. No significant connection between autoaggregation and hydrophobicity was observed. All the characteristics of these strains including biofilm formation, multiple antibiotic resistance, hydrophobicity and auto aggregation abilities made them strong candidates for CA-UTI.

Research of Associated Resistance to Antimicrobial Agents of Extended Spectrum Beta-Lactamases Escherichia Coli and Klebsiella pneumoniae Strains Isolated in Senegal

Introduction: Some strains of Escherichia coli and Klebsiella pneumoniae produce Extended Spectrum Beta-Lactamases (ESBL) may be responsible for various infections such as urinary infections. These Sick people are treated in the very serious cases by association antibiotics to class to betalactamins, aminosids and quinolons. But proliferation of multi-drug resistant strains involves decreasing therapeutic success. That’s why epidemiological study must be done in all laboratories of bacteriology. Purpose: The aim of the study was to research the resistance phenotypes of our E. coli and K. pneumoniae ESBL strains compared to others families of antibiotics. Material and methods: Thirty two (32) Extended Spectrum betalactamases E. coli and K. pneumoniae strains isolated from either hospitalized patients or sick people who came for consultation were studied. Susceptibility to antimicrobial agents was determined using an antibiotic disk (Bio-Rad) diffusion method on Mueller-Hinton agar (Bio-Rad). The results were interpreted according to the Standards of the French Antibiogram Committee (CA-SFM). Results: The study showed that most of these strains were multi-drug resistant. They were resistant to many beta-lactamines antibiotics. E. coli strains were also resistant at 70,34% to aminosids, at 96,72% to quinolons, at 58,3% to cotrimoxazol, at 26,1% to chloramphénicol and at 21,4% to colistin ; about K. pneumoniae, they were resistant at 72,6% to aminosids, at 88,95% to quinolons, at 86,7% to cotrimoxazol, at 44,4% to chloramphénicol and at 25% to colistin. But all these strains were sensitive at 100% to l’imipenem.