Browsing by Author "Tiwari, KB"
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Publication Antibacterial activities of locally used toothpastes againstdental pathogens(Institute of Medicine, 2008) Tiwari, KB; Shrestha, UT; Acharya, A; Subedi, B; Paudyal, B; Jnawali, M; Shakya, P; K.C, U; Agrawal, VPAbstract Background: Toothpastes need to contain various antimicrobial agents in order to reduce, control and prevent different kinds of dental diseases. Different brands have their own composition and concentration of ingredients for their efficacy. The consumers should aware about the facts associated with their health. Methods: The bacterial pathogens were isolated and identified from various dental samples. Antibacterial activities of 11 different toothpastes available locally in markets were assessed against the isolates by standard agar well diffusion method. Result: Monomicrobial infections were observed in all cases. The bacterial pathogens were found to be Streptococcus mutans, S. salivarius, S. sanguis, S. sobrinus and S. mitis. Of the assayed toothpastes- Colgate Total, Colgate, Anchor White and Pepsodont were found to be highly effective against the pathogens. Conclusion: The result showed that the toothpastes containing Triclosan as a major chemical ingredient posses significant antibacterial activities. Keywords: Streptococcus, Triclosan, Zone-of-inhibitionPublication Antibacterial activities of medicinal plants of Nepal(Institute of Medicine, 2008) Pokharel, K; Dhungana, BR; Tiwari, KB; Shahi, RB; Yadav, BK; Sharma, M; Shrestha, RK; Shrestha, D; Paudel, BHAbstract Background: Medicinal plants of Nepal are still remaining to be assessed for their antimicrobial properties, which may lead to discovery of broad-spectrum antimicrobial compounds. Methods: Various parts of medicinal plants, viz. Acorus calamus, Curcuma longa, Emblica officinalis, Glycyrrhiza glabra (a non-indigenous to Nepal), Justicia adhatoda and Xanthoxylum armatum, were collected from hilly regions of Nepal. The plant parts were chopped into fine pieces, air-dried at 37°C for several hours, surface sterilized and grinded to powder. The antibacterial compounds were extracted by Soxhlet Reflux method and tested against common bacterial pathogens by agar well diffusion test. Result: All the crude extracts were found to be effective against Salmonella typhi, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Staphylococcus aureus. Among tested ones E. officinalis was found to the best antibacterial plant. Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) values of the crude extract of E. officinalis were found to be 8mg/ml and 16mg/ml respectively. Similarly, MIC value of A. calamus was 128mg/ml. Conclusion: Being highly effective against both Gram-positive and Gram-negative common bacterial pathogens, the antibacterial compounds from the plants can be exploited to commercial values provided in vivo assessment of the compounds are studied. Keywords: Antibacterial agents, medicinal plants, minimum inhibitory concentration, NepalPublication Antibiogram and Plasmid profiling of clinical multidrug resistant Escherichis coli(Institute of Medicine, 2014) Shrestha, S; Mali, NM; Tiwari, KB; Adhikari, N; Shrestha, UT; Basnyat, SRAbstract Introduction: Multiple antibiotic resistances among common bacterial pathogens have been established as an alarming public health problem elsewhere. This study was aimed to explore prevalence of Extended-spectrum beta-lactamase (ESBL) producers among multi drug resistant (MDR) and plasmid profiling patterns of Escherichia coli isolated in Kathmandu Model hospital, Nepal over three months period. Methods: Altogether 49 isolates were randomly selected among the reported MDR E. coli and retested for the susceptibility pattern and ESBL production by Kirby- Bauer disc diffusion test. Minimum Inhibitory Concentration of the isolates towards (fluro) quinolones was determined by agar dilution method. Plasmids from isolates were extracted by alkaline lysis method. Results: All isolates were completely resistant to Amoxycillin but sensitive to Imipenem. A very high prevalence (44, 89.8%) of ESBL was detected. Most of the isolates were resistant to commonly uses antibiotics such as Quinolones, Tetracyclines and Cotrimoxazole. Among Quinolones, the Minimum Inhibitory Concentration (MIC) range for Nalidixic acid, Ciprofloxacin and Ofloxacin were 512->4093, 8-4096 and 1-256 µg/ml respectively. All 31 (63.3%) plasmid- harboring isolates contained a>33.5 kb sized plasmid. Among them, seven isolates possessed multiple (2 – 7) plasmids. Overall, twelve different resistance patterns were observed among the bacteria. Based on the patterns, the high molecular weight plasmid seemed to contain most of the resistance genes. Conclusion: It is suspected that multi drug resistance and ESBL production in E. coli with resistance to Quinolones may be due to their high molecular weight plasmids. So, continuous antibiotic susceptibility test and surveillance of the plasmid and chromosome of E. coli is essential as plasmid analysis has been applied to determine the evolution and spread of antibiotic resistance among isolates. Keywords: escherichia coli, antibiotic resistance pattern, multidrug resistant (MDR), extended spectrum beta- lactamases (ESBL), plasmid profiling