Naso-pharyngeal carriage and antimicrobial susceptibility of Streptococcus pneumoniae in community-acquired pneumonia in children

Original Research

Abstract

Introduction: Streptococcus pneumoniae is the most common cause of community-acquired pneumonia (CAP) in children. Recently, the rapid emergence of antibiotic-resistant pneumococci has posed enormous challenges for CAP treatment and public health. This study aims to provide clinicians with updated data about the antimicrobial susceptibility of S. pneumoniae and improve the treatment guidelines in CAP in children.

Methods: This cross-sectional and in-vitro study was conducted at three hospitals in Quang Nam province and Da Nang city in Vietnam. Pneumococcal strains were isolated from nasopharyngeal aspirate samples of 360 CAP in-patients under five years of age. The susceptibility of clinically used antibiotics was investigated using the disk diffusion test and the E-test for identifying the MIC. Multi-drug resistant (MDR) S. pneumoniae isolates were also determined.

Results: 21.9% of CAP children patients were pneumococcal carriage. The susceptibility testing demonstrated that all 56 tested pneumococcal isolates were resistant to erythromycin and azithromycin, whereas none of the isolates developed the resistance to levofloxacin, vancomycin, and linezolid. The clindamycin- and cotrimoxazole-resistant pneumococci rates were 96.4% and 87.5%, respectively. For β-lactam antibiotics, the resistance proportions of pneumococcal isolates to penicillin G, co-amoxiclav, amoxicillin, cefotaxime, and ceftriaxone were 3.6%,1.8%, 1.8%, 1.8%, and 3.6%, respectively. 83.9% of the tested isolates were MDR S. pneumoniae.

Conclusion: Our data support using penicillin G, amoxicillin, co-amoxiclav, or cefotaxime as the first-line therapy for uncomplicated-pneumococci-induced CAP in Quang Nam – Da Nang, while vancomycin, linezolid, and levofloxacin should be used as alternatives or in MDR cases. 

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Study on the analgesic, anti-inflammatory and hypouricemic effects of 50% ethanolic extract from Jasminum subtriplinerve Blume

Original Research

Abstract

Previous studies have reported in vitro antioxidant and inhibitory activity on xanthine oxidase of Jasminum subtriplinerve Blume, Oleaceae, which suggested the potential prevention of gout and supplementary treatment. This study evaluated analgesic, anti-inflammatory, and hypouricemic effects of the 50% ethanolic extract of J. subtriplinerve (EEJS) at the oral doses of 800 and 1200 mg/kg in mice. For acute oral toxicity, after oral administration of single doses of EEJS; mortality and toxic signs in male and female mice were noticed within 72 hours and 14 days. The analgesic effect was observed in acid acetic induced writhing in mouse model within 40 minutes. The anti-inflammatory effect was determined in mice-induced edema by 1% carrageenan. The hypouricemic effect was evaluated in mice with the peritoneal injection of potassium oxonate inducing acute and chronic hyperuricemia. The results showed that there was not any toxic sign in mice given orally at the maximum dose (Dmax) of 20 g EEJS/kg. At the dose of 800 and 1200 mg/kg, EEJS did exhibit analgesic effect until 40th minute. EEJS 1200 mg/kg expressed acute anti-inflammatory effect. EEJS had no acute hypouricemic effect at the oral doses of 800 and 1200 mg/kg. When given to mice with chronic hyperuricemia, 800 mg/kg EEJS reduced 30-44% blood uric acid concentration compared to pathological group. In conclusion, EEJS did not cause any toxic sign in mice at the Dmax of 20 g/kg. This extract had analgesic and chronic hypouricemic effects at the oral dose of 800 mg/kg in mice. 

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Study on preliminary screening of the triterpenoid constituents and in vitro tyrosinase inhibitory activity of dragon fruit flowers (Hylocereus undatus (Haw.) Britton & Rose)

Original Research

Abstract

The flowers of Hylocereus undatus (Haw.) Britton & Rose have been reported in vitro antioxidant and tyrosinase inhibitory activities. This study screened preliminarily the triterpenoid constituents and evaluated in vitro tyrosinase inhibitory activity of H. undatus flowers. H. undatus flowers were harvested from Binh Thuan Province, Vietnam at four different flowering stages, and their five separated parts (stamen, pistil, petals, ovary, and sepals) were extracted with ethanol. Triterpenoids were identified in the extracts by thin-layer chromatography and Liebermann - Burchard reaction. Tyrosinase inhibitory activity was evaluated using the dopachrome method with L-tyrosine substrate and kojic acid as the positive control. Results showed that at the different flowering periods, there was the formation of different parts of the flowers. The triterpenoid compounds are the main constituents in the H. undatus flower extracts. The 70% ethanol extract from H. undatus flower at the stage of 2 - 3 days before blooming exhibited the strongest tyrosinase inhibitory activity with IC50 value of 266.4 μg/mL compared to that of 7.60 μg/mL of kojic acid. In the case of separation of flower parts, 70% ethanol extracts of each part inhibited weakly the tyrosinase enzyme. In conclusion, the present study provided information about the morphological characteristics of H. undatus flower collected from Binh Thuan Province, Vietnam. Triterpenoid was found as the main constituents of the ethanolic extracts of H. undatus flower. The 70% ethanol extract from whole H. undatus flower at the stage of 2 - 3 days before blooming exhibited strong tyrosinase inhibitory activity. 

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Computer-aided structural optimization, synthesis, evaluation of the antimicrobial and cytotoxic activity of some pyrazoline derivatives

Original Research

Abstract

Introduction: In the last few decades, pyrazoline-based substances have emerged as potential antimicrobial and anticancer candidates. In concern with antimicrobial activity, this study aims to build a docking model to predict the structure of potential 2-pyrazoline derivatives. The cytotoxicity of some compounds was also evaluated to get insight into the structure–anticancer activity relationship of the 2-pyrazoline derivatives.

Methods: Docking models were built on virtual FabH enzymes using FlexX platform with 2-pyrazoline derivatives served as test sets. Afterward, derivatives with high docking scores were chemically synthesized and evaluated for antibacterial activity using the agar dilution method. Furthermore, MTT assay was used to assess the cytotoxicity of these compounds.

Results: The docking score and the in vitro minimum inhibitory concentration (MIC) value on Staphylococcus aureus (S. aureus) bacteria strongly correlate with an R-square value of 0.6751 (p < 0.0001). Four 2 pyrazoline derivatives were synthesized and evaluated for antimicrobial activity. Their MIC values on S. aureus range between 4 and 16 μg/mL, consistent with ones predicted by the docking model. Apropos cytotoxic properties, a series of 2-pyrazolines exhibit a moderate activity on HepG2, RD, and MDA-MB-231. The most active compound, HP10, has the IC50 values on these cell lines. which are 26.62 μM, 17.74 μM, 14.47 μM, respectively.

Conclusion: Our research built a docking model on the virtual S. aureus FabH enzyme with high potential in predicting antibacterial activities of different 2-pyrazoline derivatives. Moreover, our cytotoxicity results provided data for further studies on the anticancer activity of these promising derivatives.
 

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Subacute oral toxicity evaluation of the ethanolic extract of Hydnophytum formicarum Jack. tubers in Phu Quoc, Vietnam

Original Research

Abstract

The tubers of Hydnophytum formicarum Jack. have been used for the treatment of rheumatism, liver and intestinal diseases in the traditional medicine of Vietnam. The 50% ethanolic extract of H. formicarum (EEHF) has been proved anti-inflammatory and analgesic effects as well as hepatoprotective activity at the oral doses of 100 and 200 mg/kg in Swiss albino mice. The aim of this work was to study on the subacute oral toxicity of the EEHF at the doses of 100 and 200 mg/kg for 30 and 60 consecutive days in both sexes of mice. The observations were undertaken on the mortality, the body weights, the toxic signs, hematological and biochemical parameters. At the end of the experiment, the histopathology of liver and kidneys was studied. The results showed that the 100 mg/kg of EEHF did not cause any toxic signs in mice. There was no significant difference of hematological and biochemical parameters between the treated animals and the controls. Histopathological examinations of livers and kidneys showed no significant difference suggesting no morphological disturbances in treated mice. In conclusion, the results indicated that the EEHF did not cause any subacute toxicity in mice at the dose of 100 mg/kg, providing the evidence of the safety of health products from this medicinal plant.

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Botanical, genetic characteristics and preliminary screening of the phytochemical constituents of Hydnophytum formicarum Jack. in Phu Quoc forest, Vietnam

Original Research

Abstract

In Vietnamese folk medicine, Bi ky nam (H. formicarum) tuber has been widely used to treat rheumatism, liver and intestinal diseases. This work aimed to study botanical, genetic characteristics and screening of the phytochemical constituents of wild H. formicarum of Phu Quoc Island, Vietnam. Anatomical characteristics of the plant material were described. Fresh leaves were used to analyze DNA barcodes based on rbcL region amplified by PCR. Sequences of DNA products were identified by Sanger method and BioEdit 7.0.5 software, then compared to the control rbcL sequences published in GenBank by BLAST. The tuber powder was studied for pharmacognostic parameters, preliminary phytochemical screening and total phenolic contents by Folin-Ciocalteu method. Results showed that the similarity between the rbcL sequences of H. formicarum leaves collected in Phu Quoc and the control one published in Genbank was 99%. Moisture content, total ash value and acid insoluble ash value of dried tuber powder were 11.06%, 9.60% and 0.70%, respectively. Raw material contained carotenoids, triterpenoids, flavonoids, phenolics, tannins, saponins, reducing substances and amino acids. Total phenolics content was about 58.847 mg pyrrogallol equivalent/g dried powder weight. Our results provided information about botanical, genetic and preliminary phytochemical characteristics of H. formicarum growing on Phu Quoc Island. This could be useful for the authentication of H. formicarum as a medicinal material.

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