Screening Of Antimicrobial Properties Research Articles

Screening of Antimicrobial Properties and Bioactive Compounds of Pleurotus Ostreatus Extracts against Staphylococcus Aureus, Escherichia coli, and Neisseria Gonorrhoeae.

In recent years, the potential of pathogenic bacteria to acquire resistance to a variety of antimicrobial drugs has developed significantly due to the indiscriminate exposure of a number of antibiotic compounds. The purpose of this study is to determine the antibacterial capabilities and activities of crude Pleurotus ostreatus extracts against Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Neisseria gonorrhoeae (ATCC 49926), and nine multidrug-resistant clinical isolates of Neisseria gonorrhoeae. All of these isolates exhibited sensitivity to azithromycin and ceftriaxone, while the majority of antibiotic resistance was seen against penicillin G, sulphonamide, and ciprofloxacin. Fifty percent of the isolates exhibited absolute resistance to both sulphonamide and ciprofloxacin, whereas 40% of the isolates displayed absolute resistance to penicillin G. The antibacterial activity of P. ostreatus extracts examined in this investigation varied within the same species of microorganisms. Extract B and D, extracted in the presence of 20% wheat bran bagasse and 20% maize flour bagasse, respectively, had exceptional antibacterial activity against all target isolates examined. We observed the lowest concentration of antibacterial agent required to inhibit the target bacteria to be between 1 × 10-3 mg/ml and 1 × 10-6 mg/ml with an estimated probability of 0.30769, a lower 95% confidence interval (CI) of 0.126807, an upper 95% CI of 0.576307, an estimated probability of 0.15385, a lower 95% CI of 0.043258, and an upper 95% CI, respectively. The MBC of 1 × 10-3 mg/ml was seen to eliminate 31% of the target bacteria. This dose was the most inhibitive. The antibacterial activity of all the extracts examined in the current study exhibited some degree of efficacy against both clinical isolates and standard strains. However, the majority of clinically isolated bacteria exhibited greater resistance to the extracts.

In vitro antimicrobial studies of some major bioactive compounds isolated from Strychnos innocua (Delile) root bark

Plant based therapies are very essential in modern medicine, and have long been used to cure and prevent chronic diseases in many parts of the world. Medicinal herbs have been shown to have biological properties due to the presence of active compounds. Strychnos innocua, a medicinal plant from Loganiaceae, is commonly consumed for medicinal purposes in various African countries. The need to assess the usefulness of the plant’s root bark in the treatment of disease spurred this study, which involved the isolation of six bioactive compounds and screening for antimicrobial properties against some pathogens using the agar well diffusion method. Chromatography separation led to first time isolation of Umbelliferone (1), Linalool (2), Nerolidol (3), Campesterol (4), β-sitosterol (5), and 2,13-Octadecadien-1-ol (6). GC–MS and NMR spectra, as well as comparisons with published data, were used to determine their structures. The compounds exhibited strong antimicrobial activity comparable to ciprofloxacin and fluconazole against MRSA, B. subtilis, S. pyogenes, S. aureus, K. pneumoniae, E. coli, P. aeruginosa, S. typhii, A. fumigatus, C. albicans, C. krusei, and A. nigre. The MIC as well as the MBC/MFC were determined. In conclusion, the compounds (1 – 6) isolated from S. innocua root bark have remarkable antibacterial action against pathogenic microbes.

Спектр протимікробних властивостей настоянок лікарських рослин

У статті обговорені біологічні властивості рослинних препаратів, що не є настільки широко використовуваними в практичній медицині, тому їх призначення при гнійно-септичних інфекціях не могло спричинити поширеної стійкості до них. Метою роботи було встановлення та порівняння спектра протимікробних властивостей настоянок лікарських рослин для формування резерву нових джерел протимікробних засобів, одними з яких можуть бути екстракти з рослин. Скринінг протимікробних властивостей іn vitro провели для 12 рослинних настоянок на 15 тест-штамах мікроорганізмів. Виявлено наявність протимікробних властивостей у настоянок лікарських рослин, найпереконливіші результати відзначені в настоянок арніки гірської, ехінацеї пурпурової та евкаліпту. Щодо референтних штамів мікроорганізмів, мінімальна інгібуюча та мінімальна бактерицидна концентрації яких коливались від 1 : 128 до 1 : 32, помірна активність відзначена у настоянок м’яти перцевої та софори японської з показниками від 1 : 32 до 1 : 8. У свою чергу, спектр протимікробних властивостей виявився широким до колекційних штамів, що було прогнозованим, але на особливу увагу заслуговують результати, отримані з дослідження впливу на клінічні штами мікроорганізмів, які є поліантибіотикорезистентними. Так, протимікробна активність настоянок рослинного походження зменшувалась на одне розведення щодо кожного чутливого виду, а інколи співпадала, що свідчить про відсутність стійкості до даних препаратів і визначає як рівномірно чутливі референтні колекційні та клінічні штами до екстрактів рослин. Отримані результати продемонстрували, що екстракти рослин є потенційним резервом для формування нових джерел протимікробних засобів, особливо стосовно антибіотикорезистентних клінічних штамів мікроорганізмів, які формуються під постійним впливом синтетичних і напівсинтетичних препаратів.

Bioprospecting of insect nest associated actinobacteria with special reference to antimicrobial and anti HIV activity

The present study attempted to explore actinobacteria from different insect nest samples for antimicrobial activity. Totally, 43 actinobacterial colonies were recovered from ant nest, termite nest, wasp nest and blanket worm nest samples by adopting standard spread plate method. Screening of antimicrobial properties of actinobacterial strains was determined by agar plug method. Two actinobacterial strains AN1 and AN5 showed promising activity (14-18 mm inhibition) against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, carbapenem resistant Klebsiella pneumoniae and Mycobacterium smegmatis. Both the strains produced antimicrobial compound earlier on ISP2 agar when compared to ISP2 broth. Crude extracts from the strains AN1 and AN5 were produced by adopting agar surface fermentation and extracted using ethyl acetate. Based on the studied phenotypic characteristics, actinobacterial strains AN1 and AN5 isolated from ant nest were identified as Streptomyces sp. In addition to antimicrobial activity, extracts also showed anti-HIV activity. This study concluded that insect nest is a promising source for bioactive actinobacteria. Two potential Streptomyces sp. AN1 and AN5 isolated from ant nest will be promising sources for antimicrobial metabolites against drug resistant bacteria, retrovirus and mycobacterial pathogens.

Similar bacterial communities on healthy and injured skin of black tip reef sharks

BackgroundSharks are in severe global decline due to human exploitation. The additional concern of emerging diseases for this ancient group of fish, however, remains poorly understood. While wild-caught and captive sharks may be susceptible to bacterial and transmissible diseases, recent reports suggest that shark skin may harbor properties that prevent infection, such as a specialized ultrastructure or innate immune properties, possibly related to associated microbial assemblages. To assess whether bacterial community composition differs between visibly healthy and insulted (injured) shark skin, we compared bacterial assemblages of skin covering the gills and the back from 44 wild-caught black-tip reef sharks (Carcharhinus melanopterus) from the Amirante Islands (Seychelles) via 16S rRNA gene amplicon sequencing.ResultsShark skin-associated bacterial communities were diverse (5971 bacterial taxa from 375 families) and dominated by three families of the phylum Proteobacteria typical of marine organisms and environments (Rhodobacteraceae, Alteromonadaceae, Halomonadaceae). Significant differences in bacterial community composition of skin were observed for sharks collected from different sites, but not between healthy or injured skin samples or skin type (gills vs. back). The core microbiome (defined as bacterial taxa present in ≥50% of all samples) consisted of 12 bacterial taxa, which are commonly observed in marine organisms, some of which may be associated with animal host health.ConclusionThe conserved bacterial community composition of healthy and injured shark skin samples suggests absence of severe bacterial infections or substantial pathogen propagation upon skin insult. While a mild bacterial infection may have gone undetected, the overall conserved bacterial community implies that bacterial function(s) may be maintained in injured skin. At present, the contribution of bacteria, besides intrinsic animal host factors, to counter skin infection and support rapid wound healing in sharks are unknown. This represents clear knowledge gaps that should be addressed in future work, e.g. by screening for antimicrobial properties of skin-associated bacterial isolates.

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English

English

English