Browsing by Subject "Antibiotic resistance"
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Item Antibiogram and Β-Lactamase Production Test of Multidrug Resistant Staphylococcus Species from Different Clinical Specimens(Department of Microbiology, 2012) Shrestha, ChandesworiThe aim of this study is to isolate the multidrug resistant (MDR) staphylococci from various clinical specimens and test the β-lactamase enzyme in multidrug resistant staphylococci by chromogenic cephalosporin sticks. Total of 205 were isolated and identified as Staphylococcus spp. using standard microbiological technique. The isolates were classified as S. aureus and CONS based on slide and tube coagulase test. The percentage of S. aureus and CONS isolates were 67% and 33% respectively. Thus identified 98 (47.8%) staphylococci were screened as multidrug resistant by employing Kirby-Bauer disc diffusion method as recommended by Clinical Laboratory Standard Institute (CLSI 2006). On sensitivity assay of S. aureus, vancomycin and nitrofurantoin were 95.6% and 100% sensitive respectively. S. aureus were highly resistant to ampicillin (74.5%), nalidixic acid (74.2%) and oxacillin (61.7%). CONS were also highly sensitive to vancomycin and nitrofurantoin with 97.1% and 100% respectively. CONS were highly resistant to oxacillin (66.7%), cloxacillin (62.5%) and nalidixic acid (56.8%). Of the total S. aureus and CONS isolates 48.9% and 45.5% were multidrug resistant. Prevalence of MDR was found higher in male (51.1%) and age group 70-79 (66.7%). About 46.4% of OPD isolates were MDR. The multidrug resistant staphylococci on nitrocefin stick test revealed that 47% were β-lactamase producers. Among them 46.3% and 51.6% were S. aureus and CONS respectively. β-lactamase producers were highly resistant to ampicillin, cephalexin and nalidixic acid each with 93.8% resistance. On a comparative study of cloxacillin disc of various manufacturing companies, cloxacillin disc from HI-MEDIA, S. aureus and CONS showed 96% and 97.13% resistance respectively. However, for OXOID and MAST showed equal resistance of 56.25% and 61.7% respectively. Staphylococci isolated were highly sensitive to Nitrofurantoin and Vancomycin. β-lactamase positive staphylococci were highly resistant toward multiple of antibiotics. This suggests the need for the β-lactamase test prior to the antibiotic prescription.Item Phenotypic and Molecular Characterization of Methicillin- Resistant Staphylococcus Aureus (MRSA) Isolates(Faculty of Microbioloy, 2018) Bhatta, Dharm RajAvailable with full textItem Physicochemical and genomic characterization of bacteriophage against Pseudomonas aerouginosa causing urinary tract infection; An apprach to biofilm reduction.(Department of Biotechnology, 2022) Timalsina, SudipIntroduction: Pseudomonas aeruginosa is resistance to most of the antibiotics. This makes treatment of Pseudomonas aeruginosa difficult. The problem is further compounded by its ability to form biofilm. The aim of this study was to isolate lytic phage against antibiotic resistant Pseudomonas aeruginosa and to use it in the reduction of Pseudomonas aeruginosa biofilm. Methodology: Bacteriophage isolation was done by Double Layer Agar Assay method. Burst size and latent period of the phage was determined by one step growth curve experiment. Phage stability was also analyzed against different temperature and pH range. Phage cocktail was used to disrupt biofilm. The synergistic effect of phage and antibiotic in reducing biofilm was also analyzed. Effect of various external factors in phage stability was examined. Whole genome sequencing of phage DNA was done. Result: Lytic bacteriophage against Pseudomonas aeruginosa was isolated. The latent period of the phage TU_pse1B was 30 minute and burst size was 27 virion per bacterium. The optimum temperature for the phage TU_pse1B was 37:C and optimum pH was 9. Three distinct bands of phage proteins of size 35, 40 and 100KDa were observed after performing SDS PAGE. Phage DNA size was determined to be larger than 10 Kb from agarose gel electrophoresis. Whole genome sequencing of phage revealed its size to be 43,428 nucleotides (43 Kb) in length and the GC content of 62.16%. Calcium ion increased the phage adsorption. Phage showed stability against SDS and osmotic shock whereas it was susceptible to ethanol, acetone and CTAB. Phage TU_pse1B reduced the biofilm by 60.99% whereas Phage TU_pse1Bi reduced the biofilm by 60.37%. Synergism of phage and antibiotic was observed in reducing biofilm. Phage plus antibiotic reduced biofilm by further 26.67% than phage alone. Conclusion: Phage TU_pse1B showed good stability to various physiochemical factors as well as it was efficient in reducing Pseudomonas aeruginosa biofilm. So, this phage can be a good candidate for controlling antibiotic resistant Pseudomonas aeruginosa. Keywords: Antibiotic resistance, Biofilm, SDS, Phage cocktail, AST, Burst size.Item Screening of Novel Genes Involved in Bio-Film Mediated Resistance to Antibiotics in MDR Pseudomonas aeruginosa(Department of Biotechnology, 2022) Manandhar, Padma RatnaAvailable with full text