School of Pathology (Journal Articles)

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Browsing School of Pathology (Journal Articles) by Department "Clinical Microbiology and Infectious Diseases"

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    ABBV744 as a potential inhibitor of SARSCoV2 main protease enzyme against COVID19
    (Nature Research) Zeynab Fakhar; Shama Khan; Afrah Alkhuriji; Suliman Y. AlOmar; Aijaz Ahmad
    A new pathogen severe acute respiratory syndrome coronavirus 2 (SARS‑CoV‑2) has spread worldwide and become pandemic with thousands new deaths and infected cases globally. To address coronavirus disease (COVID‑19), currently no effective drug or vaccine is available. This necessity motivated us to explore potential lead compounds by considering drug repurposing approach targeting main protease (Mpro) enzyme of SARS‑CoV‑2. This enzyme considered to be an attractive drug target as it contributes significantly in mediating viral replication and transcription. Herein, comprehensive computational investigations were performed to identify potential inhibitors of SARS‑CoV‑2 Mpro enzyme. The structure‑based pharmacophore modeling was developed based on the co‑crystallized structure of the enzyme with its biological active inhibitor. The generated hypotheses were applied for virtual screening based PhaseScore. Docking based virtual screening workflow was used to generate hit compounds using HTVS, SP and XP based Glide GScore. The pharmacological and physicochemical properties of the selected lead compounds were characterized using ADMET. Molecular dynamics simulations were performed to explore the binding affinities of the considered lead compounds. Binding energies revealed that compound ABBV‑744 binds to the Mpro with strong affinity (ΔGbind −45.43 kcal/mol), and the complex is more stable in comparison with other protein–ligand complexes. Our study classified three best compounds which could be considered as promising inhibitors against main protease SARS‑CoV‑2 virus
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    National sentinel site surveillance for antimicrobial resistance in Klebsiella pneumoniae isolates in South Africa, 2010-2012
    (South African Medical Association, 2014-08) Perovic, O.; Singh- Moodley, A.; Duse, A.; Elliott, G.; Bamford, C.; Swe Swe-Han, K.; R Kularatne, R.; Lowman, W.; Whitelaw, A.; Nana, T.; Wadula, J.; Lekalakala, R.; Saif, A.; Marais, E.
    Background: The increasing rates of antimicrobial resistance observed in the nosocomial pathogen Klebsiella pneumoniae are of major public health concern worldwide. Objectives: To describe the antibiotic susceptibility profiles of K. pneumoniae isolates from bacteraemic patients submitted by sentinel laboratories in five regions of South Africa from mid-2010 to mid-2012. Molecular methods were used to detect the most commonly found extended-spectrum beta lactamase (ESBL) and carbapenemase resistance genes. Methods: Thirteen academic centres serving the public healthcare sector in Gauteng, KwaZulu-Natal, Free State, Limpopo and Western Cape provinces submitted K. pneumoniae isolates from patients with bloodstream infections. Vitek 2 and MicroScan instruments were used for organism identification and susceptibility testing. Multiplex polymerase chain reactions (PCRs) were used to detect blaCTX-M, blaSHV and blaTEM genes in a proportion of the ESBL isolates. All isolates exhibiting reduced susceptibility to carbapenems were PCR tested for blaKPC and blaNDM-1 resistance genes. Results: Overall, 68.3% of the 2 774 isolates were ESBL-positive, showing resistance to cefotaxime, ceftazidime and cefepime. Furthermore, 46.5% of all isolates were resistant to ciprofloxacin and 33.1% to piperacillin-tazobactam. The major ESBL genes were abundantly present in the sample analysed. Most isolates (95.5%) were susceptible to the carbapenems tested, and no isolates were positive for blaKPC or blaNDM-1. There was a trend towards a decrease in susceptibility to most antibiotics. Conclusion: The high proportion of ESBL-producing K. pneumoniae isolates observed, and the prevalence of ESBL genes, are of great concern. Our findings represent a baseline for further surveillance in SA, and can be used for policy and treatment decisions.