Abstract:A delivery system consisting of chitosan coated liposomes was tested for its ability to deliver drugs over a period of time. Amoxicillin was used as the drug of choice and was entrapped in liposomes made of egg yolk lecithin and coated with chitosan with the aid of Tween 80 and sodium tripolyphosphate. These nanoparticles were monitored for the release of the drug in vitro. The activity of the released amoxicillin was measured against Staphylococcus aureus (NCTC-6571 strain) in BHI broth medium. The percentage of drug released with time was measured by HPLC. The nanoparticles showed sustained release of amoxicillin over a period of 24 hours. Approximately 80 % of the encapsulated drug was released in the first 10 hours. A sufficient drug release to kill the bacteria was obtained in 4 hours and a steady increase in drug concentration was observed up to 8 hours of testing. This study has enabled the model formulation of a sustained release delivery system for amoxicillin in vitro capable of delivering the drug over a period of 8 hours, which may enable drug activity such that the number of times of administration is reduced.
The prevalence and acquisition of MRSA colonization in an Orthopaedic Unit in Sri Lanka were studied over an 18 month period. 260 of 1684 patients screened on admission were colonized with MRSA. Patients who were negative at preliminary screening were rescreened at weekly intervals during their hospital stay. Of 1424 patients who were rescreened, 170 acquired MRSA. This information is beneficial in planning and implementing suitable infection control procedures in Sri Lankan hospitals.
Holarrhena mitis (Vahl) R.Br. ex Roem. & Schult. which is an endemic plant growing mainly in the dry regions of the low-country has been used in the treatment of dysentery in Ayurvedic medicine. During the present study, we tested antibacterial, antifungal, antioxidant activities and brine shrimp lethality, as well as the total phenolic content of the dichloromethane, ethyl acetate and methanol extracts of the bark and leaves of H. mitis. The methanol extract of bark produced a measurable zone of inhibition against two Candida species, namely Candida albicans, Candida krusei among all five tested species and against both dermatophytes, Microsporum gypseum and Tricophyton mentagrophytes. In addition, the methanol extract of bark showed very strong antifungal activity against C. krusei (20 mm), which is very close to that of the positive control ketoconazole (22 mm). Both dicholoromethane extracts of bark and leaves and methanol extracts of leaves showed an activity against both tested strains of Staphylococcus aureus but were negative against Escherichia coli and Salmonella enteritidis. However, the rest of the extracts exerted an active against all the tested bacterial strains. In the brine shrimp cytotoxicity assay, the dichloromethane extracts of both leaves and bark showed lower LC 50 values (27.13 ppm and 9.38 ppm, respectively) than that of positive control, K 2 Cr 2 O 7 , (35.74 ppm) indicating cell toxicity. Compared to the positive control, DL-α-tocopherol (IC 50 : 12.2 ppm), the antioxidant activity of the ethyl acetate and methanol extracts of leaves exhibited comparable activity (IC 50 :16.9 ppm and 29.8 ppm, respectively). Antioxidant activity correlated well with the polyphenol content of methanol and ethyl acetate extracts (473.25 and 138.74 mg (GAE) /g, respectively) of leaves, with respect to gallic acid. These empirical results revealed that methanol extract of bark of H. mitis showed strong antifungal activity as well as very low brine shrimp lethality indicating that it would be a potential nontoxic anti-fungal natural product. The dichloromethane extracts exhibited strong brine shrimp lethality and may contain potential natural anticancer lead compounds. Ethyl acetate extracts of both leaves and bark having significant antibacterial activity, would be source of potential antibacterial lead compounds.
Background Nasopharyngeal colonization is considered a necessary step in the initiation of pneumococcal diseases. Real time PCR (RT-PCR) is an alternative approach for the identification and quantification of pneumococci directly from samples. Objectives To compare pneumococcal detection rates using culture-based method versus RT-PCR direct detection and to quantify pneumococcal colonization in two study cohorts (healthy children and hospitalized children with respiratory symptoms) using quantitation through RT-PCR. Methodology A total of 101 nasopharyngeal swabs (NPS) from healthy children and 183 NPSs from hospitalized children with respiratory symptoms were included in the study. None of the children were vaccinated. All children were between 2 months to 2 years. In parallel to routine culture and identification, a RT-PCR assay targeting the lytA gene was done. Results Considering all 284 samples tested, colonization rate by conventional culture was 41.2% (n = 117) while positive colonization using RT-PCR was 43.7% (n = 124). The colonization rate detected by RT-PCR in the healthy cohort was 33.7% (n = 34) and it was 49.2% (n = 90) in the hospitalized cohort. It was 37.6% (n = 38) and 43.2% (n = 79) for the two cohorts by culture. The mean Cq value for the healthy cohort is 29.61 (SD 2.85) and 28.93 (SD 3.62) for the hospitalized cohort. With the standard curve obtained from amplifying a dilution series of control DNA, the mean amount of genomic DNA copy numbers detected in children with respiratory symptoms was log10 7.49 (SD 1.07) while it was log10 7.30 (SD 0.23) in healthy children and the difference was not statistically significant. Conclusions The overall colonization rate was higher when detected using RT-PCR compared to culture. However, it was lower in the healthy group when detected with RT-PCR compared to culture. Even though there was a higher detection of pneumococcal colonization density in children with respiratory symptoms, this was not significantly higher unlike many previous studies. Therefore, the use of RT-PCR to detect pneumococcal colonization needs further evaluation with careful analysis of interpretation and confounders.
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