Detection Of Antimicrobial Activity Research Articles

Biological properties of sea buckthorn (Hippophae rhamnoides L.) derived products.

Sea buckthorn is a good and possible source of a wide range of bioactive compounds with a positive effect on the human body, especially polyphenols and carotenoids. The present study aimed to evaluate the antioxidant and antimicrobial activities of Hippophae rhamnoides L. products - 100% oil, 100% juice, dry berries, and tea (dry berries, leaves, and twigs). The antioxidant activity was determined by DPPH radical scavenging and molybdenum reducing antioxidant power methods. The content of phytochemicals (polyphenols, flavonoids, carotenoids) was measured by colorimetric methods. The detection of antimicrobial activity was carried out using the disc diffusion method and an evaluation of minimal inhibition concentration against three species of Gram-negative bacteria: Escherichia coli CCM 3988, Salmonella enterica subsp. enterica CCM 3807, Yersinia enterocolitica CCM 5671, and three Gram-positive bacteria: Bacillus thuringiensis CCM 19, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461. All the tested sea buckthorn products had a high antioxidant activity. The highest content of total polyphenols (204.26 mg GAE/g), flavonoids (30.00 mg QE/g), and carotenoids (0.34 mg/g) were identified in 100% sea buckthorn juice. Maximal values of the antioxidant activity were found using the DPPH method for 100% oil (8.75 mg TE/g) and molybdenum reducing power for tea (196.41 mg TE/g). All the tested products showed strong antimicrobial activity against the tested bacteria, confirmed by both methods - disc diffusion (especially for Yersinia enterocolitica CCM 5671) and minimal inhibitory concentration. The pronounced antioxidant and antibacterial properties of sea buckthorn products indicate the importance of sea buckthorn application in health promotion and agricultural practice.

Metabolites from endophytic Aspergillus fumigatus and their in vitro effect against the causal agent of tuberculosis

ABSTRACT Tuberculosis (TB) remains one of the most deadly communicable infectious diseases, causing 1.4 million deaths in 2015 worldwide due to many conditions, including the inadequate treatment and the emergence of multidrug-resistant strains of the causal agent, Mycobacterium tuberculosis. Therefore, drugs developed from natural sources, as microorganisms and plant extracts, are a frequent target for the research and discovery of antimicrobial compounds. The current study started the characterization of compounds produced by an Aspergillus fumigatus isolated from copaíba (Copaifera multijuga) that efficiently inhibits M. tuberculosis by releasing the compounds into the fermentation broth under specific culture conditions. A preliminary assay was carried out with a correlate species, M. smegmatis, aiming to detect an antimicrobial effect related to A. fumigatus fermentation broth. The direct use of this substrate in antibiosis assays againstM. tuberculosis H37Rv strain (ATCC 27294) allowed the detection of antimicrobial activity with a minimal inhibitory concentration of 256 μg mL-1, demonstrating that purification processes developed by the Biotage Flash Chromatography System are robust and reliable techniques for purification of compounds from natural sources. Also, this chromatographic system can be used in combination with specific biochemical tests, improving the search for reliable results. We conclude that this fraction can express a broad action range, inhibiting both Mycobacterium species used as target organisms.

37 Optimization of supercritical carbon dioxide extraction conditions of Semen cassiae volatile oil using response surface methodology and antimicrobial activity detection

Objectives The objective of this project was to study the process of extracting Semen cassia. The volatile components of Semen cassia were analyzed using supercritical CO2 extraction (SCDE). Based on a single factor experiment, response surface methodology was used to investigate the extraction of volatile oil. According to the fitted curves under different conditions, the effects of pressure, temperature and time on extraction and interactions between various factors were determined. Antimicrobial activity was also measured. Methods A Box-Behnken central composite design method was used based on single factor experiments. The influence of extraction temperature, extraction time and extraction pressure on extraction yield was studied. The response surface method was employed to analyze the results of experiments. The disk diffusion method was used to detect the antimicrobial activity of Semen cassiae volatile oil. Results The results indicated that the optimum extraction conditions were as follows: extraction temperature 51°C, extraction time 3.22 hours and extraction pressure 25 MPa. Extraction yield reached 2.34%. The volatile oil of Semen cassiae extracted from the tested strains showed antimicrobial activity, with MIC values ranging from 2.5 to 5 mg/mL. Conclusions SCDE is a stable and efficient process. Semen cassiae volatile oil had antimicrobial activity which could provide a theoretical basis for application of this oil.

Sorting Out Antibiotics' Mechanisms of Action: a Double Fluorescent Protein Reporter for High-Throughput Screening of Ribosome and DNA Biosynthesis Inhibitors.

In order to accelerate drug discovery, a simple, reliable, and cost-effective system for high-throughput identification of a potential antibiotic mechanism of action is required. To facilitate such screening of new antibiotics, we created a double-reporter system for not only antimicrobial activity detection but also simultaneous sorting of potential antimicrobials into those that cause ribosome stalling and those that induce the SOS response due to DNA damage. In this reporter system, the red fluorescent protein gene rfp was placed under the control of the SOS-inducible sulA promoter. The gene of the far-red fluorescent protein, katushka2S, was inserted downstream of the tryptophan attenuator in which two tryptophan codons were replaced by alanine codons, with simultaneous replacement of the complementary part of the attenuator to preserve the ability to form secondary structures that influence transcription termination. This genetically modified attenuator makes possible Katushka2S expression only upon exposure to ribosome-stalling compounds. The application of red and far-red fluorescent proteins provides a high signal-to-background ratio without any need of enzymatic substrates for detection of the reporter activity. This reporter was shown to be efficient in high-throughput screening of both synthetic and natural chemicals.

Prospective Blinded Laboratory Assessment of Prophylactic Antibiotic Compliance in a Pediatric Outpatient Setting

Prophylactic antibiotics are commonly used to prevent urinary tract infections in children with conditions such as vesicoureteral reflux. Patient compliance with antibiotics is salient, given the effects that noncompliance can have on development of antibiotic resistance and outcomes of clinical trials. Prior series have shown variable compliance (17% to 70%). However, no study has used objective methods. We hypothesized that direct measurement of urine antibiotic levels can reveal poor compliance. During a pediatric urology clinic visit patients 0 to 18 years old taking trimethoprim prophylaxis for any urological diagnosis were invited to participate in the study. They were unaware of any potential urine testing before the visit. Urine was sent for chromatography to quantify trimethoprim levels. Parents also completed a compliance self-assessment. Of patients invited to participate 97% consented (54 patients). Of the patients 91% were compliant based on urine levels. Factors not associated with compliance included age, gender, self-report of compliance, duration of time on antibiotics, insurance status and history of breakthrough infection, surgery, pyelonephritis or hospitalization. This study demonstrates the highest compliance reported for children taking prophylactic antibiotics to prevent urinary tract infection. We attribute this unexpected result to the discussion by specialists of 1 problem for the duration of an office visit. All education in this study was part of clinical care. Thus, our results should be generalizable to nonstudy environments. Future studies should confirm whether this high level of compliance can be achieved by nephrologists and pediatricians. If such compliance cannot be achieved at nonsurgical clinics, then early referral to a pediatric urologist may be warranted.

Honey bee drones maintain humoral immune competence throughout all life stages in the absence of vitellogenin production

Drones are haploid male individuals whose major social function in honey bee colonies is to produce sperm and mate with a queen. In spite of their limited tasks, the vitality of drones is of utmost importance for the next generation. The immune competence of drones - as compared to worker bees - is largely unexplored. Hence, we studied humoral and cellular immune reactions of in vitro reared drone larvae and adult drones of different age upon artificial bacterial infection. Haemolymph samples were collected after aseptic and septic injury and subsequently employed for (1) the identification of immune-responsive peptides and/or proteins by qualitative proteomic analyses in combination with mass spectrometry and (2) the detection of antimicrobial activity by inhibition-zone assays. Drone larvae and adult drones responded with a strong humoral immune reaction upon bacterial challenge, as validated by the expression of small antimicrobial peptides. Young adult drones exhibited a broader spectrum of defence reactions than drone larvae. Distinct polypeptides including peptidoglycan recognition protein-S2 and lysozyme 2 were upregulated in immunized adult drones. Moreover, a pronounced nodulation reaction was observed in young drones upon bacterial challenge. Prophenoloxidase zymogen is present at an almost constant level in non-infected adult drones throughout the entire lifespan. All observed immune reactions in drones were expressed in the absence of significant amounts of vitellogenin. We conclude that drones - like worker bees - have the potential to activate multiple elements of the innate immune response.

Detection of antimicrobial activity in accessory gland secretions of the virgin male red palm weevil, Rhynchophorus ferrugineus

Detection of antimicrobial activity in accessory gland secretions of the virgin male red palm weevil, Rhynchophorus ferrugineus

Detection of antimicrobial activities and bacteriocin structural genes in faecal enterococci of wild animals

The production of antimicrobial activities as well as the presence of bacteriocin structural genes (entA, entB, entP, entQ, cylL, entAS-48, bac31, and entL50A/B) were studied in 140 non-selected faecal enterococcal isolates recovered from wild animals. Eight different indicator strains (including Listeria monocytogenes, Pediococcus pentosaceus, and different enterococcal species) were used for antimicrobial activity detection. Twenty-five of the 140 enterococci (18%) showed antimicrobial activity against L. monocytogenes and 33 additional isolates (24%) showed antimicrobial activity against other indicator strains, but Listeria. At least one bacteriocin structural gene was detected in 17 of the 25 enterococci with antimicrobial activity against L. monocytogenes and different combinations of entA, entB, entP, entQ, entL50A/B, and cylL genes were detected; entA and entB were the most prevalent detected genes, and they were generally associated. Bacteriocin structural genes were detected in 10 of 33 isolates with antimicrobial activity against indicator strains other than Listeria, and the cylL gene was the most prevalent one, especially in E. faecalis isolates.

Isolation of Some Antimicrobial Compounds of Red Wine by OPLC Flowing Eluent Wall Technique

The first results of the combination of BioArena and OPLC with flowing eluent wall technique (FEW) show an especially attractive solution of the detection of antimicrobial activity and compound isolation based on peak collection. Because of the different separation mechanisms applied for on-line FEW–OPLC isolation of red wine constituents and for further off-line OPLC investigation of fractions, the combined system yields high selectivity.

Screening for antimicrobial activity among bacteria isolated from the Amazon Basin

Bacteria producing antimicrobial activity were identified among 86 isolates from aquatic environments of Brazilian Amazon Basin. Antimicrobial activity against at least one indicator strain was detected for 59 isolates (68.6%). Inhibitory activity was mostly against Gram-positive bacteria, such as Listeria monocytogenes and Bacillus cereus. The antimicrobial substances produced by 19 strains that showed higher inhibitory activity were partially characterized. These antimicrobial substances showed thermal resistance for up to 100°C and partial resistance to proteolytic treatment. Some antimicrobials were partially resistant to pronase E at 2 mg ml -1 or to treatment with trichloroacetic acid. Detection of antimicrobial activity on polyacrylamide gels revealed that the molecular weight of the compounds was lower than 14 kDa. Several strains showed antibacterial activity, which in some cases appear to be related to antimicrobial peptides. The potential of these microorganisms to produce useful antimicrobial compounds is great and must be better explored.

Antimicrobial Activity of Teucrium plectranthoides Gamble Essential Oil

Objective: Detection of antimicrobial activity of Teucrium plectranthoides essential oil. Materials and methods: Essential oil was separated from Teucrium plectranthoides by hydrodistillation. Antimicrobial activity of the essential oil was tested against seven bacteria and eight fungi using filter paper disk diffusion method. Results: The growth of almost all microorganisms was inhibited by the activity of the essential oil. Conclusion: The essential oil of T. plectranthoides can be used to develop commercial microbicides.

The synthesis of antimicrobial peptides in the skin of Rana esculenta is stimulated by microorganisms.

SPECIFIC AIMIn the present study, we investigated the synthesis of antimicrobial peptides in skin glands of the frog Rana esculenta under different conditions. We show by HPLC analysis, detection of antimicrobial activity, and gland morphology that frogs kept in a sterile environment do not synthesize these peptides; their synthesis is induced by the presence of microorganisms.PRINCIPAL FINDINGS1. Induction of peptide synthesis by microorganismsTo study the synthesis of antimicrobial peptides in vivo, specimens of R. esculenta were repeatedly stimulated to deplete skin glands. Frogs were then exposed to different environmental conditions. A first group was kept in water in the presence of bacteria of the natural flora at 106 cfu/ml, and a second group was maintained for the same amount of time in water containing tetracycline and erythromycin at a final concentration of 80 and 150 μg/ml, respectively. After 1 and 2 wk, the antimicrobial activity, expressed as cecropin A units, as well as the reversed-phas...

Detection of Antimicrobial Activity in Urine for Epidemiologic Studies of Antibiotic Use

Antibiotic resistance is the inevitable consequence of the selective pressure of antimicrobial drug use and the adaptive plasticity of the microorganisms. Excessive and irrational use of antimicrobial drugs is a problem in all countries. It is particularly troublesome in developing countries where there is a heavy burden of infectious diseases. This study was designed to determine whether detection of antimicrobial activity in the urine might be a useful tool for epidemiologic studies of the interaction between antibiotic use and resistance in developing countries. A laboratory marker is necessary because the history of antimicrobial drug use may be unreliable. Serial specimens or spontaneously voided urine were obtained from healthy volunteers given a single oral dose of commonly used antimicrobial drugs. Urine was also obtained from hospitalized patients the morning after the last dose of an antimicrobial drug and from untreated controls. Assays were performed with standard American Type Culture Collection (Rockville, MD) stains of Bacillus stearothermophilus, Escherichia coli, and Streptococcus pyogenes. Antimicrobial activity could not be detected in pretreatment urine. After a single oral dose, the β lactam antibiotics and erythromycin could be detected for about 12 to 24 hours, whereas clindamycin, tetracycline, trimethoprim/sulfamethoxazole, and ciprofloxacin could be detected for 48 or more hours. In hospitalized patients, receiving multiple drugs, the following were the sensitivity and specificity for detection of antimicrobial activity: for B. stearothermophilus, 100.0% and 85.9%, respectively; for S. pyogenes, 94.9% and 94.9%, respectively; and for E. coli, 71.8% and 98.7%, respectively. The combination of E. coli and Streptococcus pyogenes exhibited a sensitivity of 97.4% and specificity of 94.9%. Detection of antimicrobial activity in urine is a promising method to determine antimicrobial drug use in epidemiologic studies, particularly in populations in which drug use history is unreliable.