Browsing by Author "Liyanapathirana, V."

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    Determination of antibacterial activity of 6β-hydroxybetunolic acid and interaction with oxacillin
    (Institute of Chemistry Ceylon Adamantane House, Rajagiriya, Sri Lanka., 2020) Wickramasingha, W. G. D.; Jayasinghe, S.; Karunaratne, D. N.; Liyanapathirana, V.; Ekanayake, A.; Karunaratne, V.
    Various strides have been undertaken with successful results in the treatment and cure of significant number of bacterial infections. However, many bacteria are becoming resistant to some of the prevailing drugs due to either the misuse or the prolonged use of the available antibiotics increasing the necessity for discovering new antibiotics to combat resistant microorganisms. Plants and their secondary metabolites can be considered as good sources of scaffolds to provide structurally diverse bioactive compounds as potential therapeutic agents and combination of them with standard antibiotic to obtain synergistic effect. The objective of this study was to determine the antibacterial activity of one of a lupeol type triterpenoid (6β-hydroxybetunolic acid) isolated from the bark of Schumacheria castaneifolia Vahl. which is an endemic plant to Sri Lanka and to determine the synergistic effect with Oxacillin. Antimicrobial activity of 6β-hydroxybetunolic acid was evaluated utilizing micro broth dilution assay in 96 well plates against two standard strains of Staphylococcus aureus, 4 strains of clinically isolated Methicillin resistant S. aureus, standard strains of Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, carbepenemas producing Kebsiella pneumonia and carbepenemas non-producing Kebsiella pneumonia and four strains of clinically isolated Acinetobacter sp. Synergistic effect of the combination of 6β-hydroxybetunolic acid and Oxacillin was tested against Standard strain of S. aureus and MRSA using checker board method. Results revealed that 6β-hydroxybetunolic acid shows significant antibacterial activity only against the Gram positive strains; MIC values of S. aureus (ATCC 29213), S. aureus (ATCC 29213), E. faecalis (ATCC 29212) and four MRSA strains were 32, 16, 32, 32, 32, 32, 16 ppm respectively. However MIC value of Oxacilin against S. aureus (ATCC 29213) was 0.25 ppm. 6β-hydroxybetunolic acid has synergistic effect with Oxacillin against S. aureus and additive effect against all the tested MRSA. These results concluded that the antibacterial activity of 6β-hydroxybetunolic acid is predominantly depending on the cell wall difference of the bacteria.
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    Identification of staphylococci contaminating clinical white coats of 4th year medical students
    (Faculty of Medicine, University of Kelaniya, Sri Lanka, 2021) Daraniyagala, H.U.; Dahanayake, O.S.; Dasanayake, A.P.; Dayarathna, M.P.; Dayarathna, S.N.; Dayasiri, K.G.; de Silva, D.N.; de Silva, S.A.; de Silva, N.U.; de Silva, D.; de Zoysa, D.S .; Vidanapathirana, G.; Dissanayake, R.U.; Ekanayake, A.; Liyanapathirana, V.
    Introduction: Infections caused by-resistant bacteria (ARB) have become a major global issue. Medical students’ clinical white coats can harbor these organisms and function as a possible reservoir for ARB transmission during their clinical training. More common species that contaminate clinical white coats include Staphylococcus aureus and its antibiotic-resistant variation, Methicillin-Resistant Staphylococcus aureus (MRSA). Objectives: To determine the prevalence of S. aureus and MRSA contamination of clinical white coats worn by medical students. Methods: A cross-sectional study was done with the participation of 4th-year medical students of the Faculty of Medicine, University of Peradeniya. Swabs were taken from the pockets and sleeves of the clinical white coats, and S. aureus was identified using routine microbiological methods. Disc diffusion-based cefoxitin sensitivity test was used to identify MRSA isolates among the S. aureus. Results: S. aureus has contaminated 53 (35.1%) of the 151 white coats of participants. MRSA was found in 20 (30.30%) of the isolates, accounting for 15 (9.9%) of the total participants. Factors analysed, including sex, type of clinical appointment and frequency of washing white coats were not found to be significantly associated with contamination by either of bacteria. Conclusions: Clinical white coats worn by medical students were found to be heavily contaminated with S. aureus and MRSA. As a result, these coats can be regarded as a potential mode of infection transmission between individuals. Therefore, steps should be taken to rectify the proper use and cleaning of medical students’ white clinical coats.