Objective To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probiotics. Methods Ant...Objective To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probiotics. Methods Antimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR. Results Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis. Conclusion Antibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.展开更多
Objective:To investigate the antibacterial and cytotoxic activity of fourteen different edible vegetables methanolic extract from Bangladesh.Methods:The antibacterial activity was evaluated using disc diffusion assay ...Objective:To investigate the antibacterial and cytotoxic activity of fourteen different edible vegetables methanolic extract from Bangladesh.Methods:The antibacterial activity was evaluated using disc diffusion assay method against 12 bacteria(both gram positive and gram negative).The plant extracts were also screened for cytotoxic activity using the brine shrimp lethality bioassay method and the lethal concentrations(LC_(50))were determined at confidence intervals by analyzing the data on a computer loaded with"Finney Programme??Results:All the vegetable extracts showed low to elevated levels of antibacterial activity against most of the tested strains(zone of inhibition=5-28 mm).The most active extract against all bacterial strains was from Xanthium indicum which showed remarkable antibacterial activity having the diameter of growth inhibition zone ranging from 12 to 28 mm followed by Alternanthera sessilis(zone of inhibition=6-21 mm).All extracts exhibited considerable general toxicity towards brine shrimps.The LC_(50)value of the tested extracts was within the range of 8.447 to 60.323μg/mL with respect to the positive control(vincristine sulphate)which was 0.91μg/mL.Among all studied extracts,Xanthium indicum displayed the highest cytotoxic effect with LC_(50)value of 8.447μg/mL.Conclusions:The results of the present investigation suggest that most of the studied plants are potentially good source of antibacterial and anticancer agents.展开更多
A rotating disc column (RDC) with inner diameter 68 mm and 28 compartments is used in this study. Parameters including Sauter mean diameter, hold-up and mass transfer coefficient are measured experimentally un-der dif...A rotating disc column (RDC) with inner diameter 68 mm and 28 compartments is used in this study. Parameters including Sauter mean diameter, hold-up and mass transfer coefficient are measured experimentally un-der different operating conditions. The correlations in literature for molecular diffusion and enhancement factor equation including eddy diffusion, circulation and oscillation of drops are evaluated. A new equation for the effec-tive diffusion coefficient as a function of Reynolds number is proposed. The calculated values of mass transfer co-efficient and column height from the previous equations and present equation are compared with the experimental data. The results from the present equation are in very good agreement with the experimental results, which may be used in designing RDC columns.展开更多
Camellia sinensis Linn is a well-known medical herb that grows in various parts of the world. In the current study, the antimicrobial activity of methanol extract from C. sinensis leaves against Lactococcus garvieae a...Camellia sinensis Linn is a well-known medical herb that grows in various parts of the world. In the current study, the antimicrobial activity of methanol extract from C. sinensis leaves against Lactococcus garvieae and Aeromanas hydrophila isolated from rainbow trout (Oncorhynchus mykiss) was investigated. The growth inhibitory effects of green tea extract was determined by disc diffusion method (3 times on different days), minimum inhibitory concentration (MIC) using serial dilution and minimum bactericidal concentration (MBC). For the L. garvieae and A. hydrophila, the zone diameter inhibition (ZDI) of extract ranged 2.30 - 16.5 mm. The highest ZDI (16.50 ± 1.12 mm) for L. garvieae was observed at 100 mg•ml-1 and for A. hydrophila (16.20 ± 0.95 mm) at 250 mg•ml-1 concentration of green tea extract (P •ml-1 concentrations of extract, ZDI values of A. hydrophila and L. garvieae showed significant difference (P < 0.05). The lowest MIC value for the extract was 0.8 mg•ml-1 against both L. garvieae and A. hydrophila. From the results of the present study, it can be concluded that methanol extract of C. sinenses leaves could be effective for the inhibition of A. hydrophila and L. garvieae in rainbow trout.展开更多
Objective: To determine the bioactive phytochemicals and antimicrobial activity of leaf and stem ethanolic extracts from Muntingia calabura L.(M. calabura).Methods: Dried leaves and stems of M. calabura were extracted...Objective: To determine the bioactive phytochemicals and antimicrobial activity of leaf and stem ethanolic extracts from Muntingia calabura L.(M. calabura).Methods: Dried leaves and stems of M. calabura were extracted with 95% ethanol. The antibacterial and antifungal activities of the extracts were examined using the disc diffusion assay. The minimum inhibitory concentration(MIC) of each extract showing antimicrobial activity was determined. The dried extracts were subjected to phytochemical screening to determine the presence of bioactive components. Total phenolic and flavonoid contents were also determined by the Folin–Ciocalteu method and the aluminum chloride method, respectively.Results: Varying degrees of antimicrobial activity were exhibited by the leaf and stem extracts against Pseudomonas aeruginosa(P. aeruginosa), Salmonella typhimurium,Staphylococcus aureus(S. aureus), Bacillus subtilis, and Candida albicans(C. albicans),with minimal activity against Escherichia coli. Based on the MIC, the extracts showed the highest activity against C. albicans, S. aureus and P. aeruginosa. Phytochemical screening revealed the presence of sterols, flavonoids, alkaloids, saponins, glycosides and tannins in the leaf extract; however, no triterpenes were detected. In the stem extract,triterpenes were detected along with relative amounts of flavonoids, saponins, glycosides and tannins. Alkaloids and sterols were absent in the stem extract.Conclusions: M. calabura leaf and stem ethanol extracts are potential sources of antibacterial agents against P. aeruginosa and S. aureus. This study reports for the first time the high degree of antifungal activity of M. calabura ethanolic extract, especially against C. albicans.展开更多
Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts(petroleum ether, ethanol and water) prepared from some fungal mycelia.Methods: Seven fungal mycelia were prepared, ini...Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts(petroleum ether, ethanol and water) prepared from some fungal mycelia.Methods: Seven fungal mycelia were prepared, initially extracted with acidified ethanol(0.2 mol/L HCl in 80% ethanol), yielding the raw crude extracts. The obtained extracts were then further partitioned with petroleum ether(F1), ethanol(F2) and water(F3). All the fractions were tested for antimicrobial activity using the disc diffusion assay.Results: Our data showed that all the fractions could inhibit the testing bacteria.However, the inhibitory activity was found to be dependent on(i) the fungal strains used;(ii) the solvent extracted; and(iii) the testing bacteria assayed. In general, the ethanolic extracts(F2) derived from all fungi displayed highest inhibitory activity against the testing bacteria except for Chaetomium sp.Conclusions: The findings of the present study concluded that the extracts prepared from the fungal mycelia had the bioactive compounds with antibacterial property. This study is a pioneering work and further study should be carried out for development of the new drug leads.展开更多
Antimicrobial drug resistance is a rising concern in the treatment of infectious diseases and necessitates the need for discovery of novel, potent antimicrobial compounds to combat antibiotic resistance. Since natural...Antimicrobial drug resistance is a rising concern in the treatment of infectious diseases and necessitates the need for discovery of novel, potent antimicrobial compounds to combat antibiotic resistance. Since natural environment remains a potential source of novel antimicrobial products, this preliminary study was performed to test the potential of soils from Kericho County for antibiotic-producing Actinomycetes. Soil samples (214) were randomly collected from virgin soils of Kipkelion East, Kipkelion West, Belgut, Ainamoi, Sigowet and Bureti sub-counties in Kericho County from a depth of between 11 cm - 16 cm from the surface of the soil profile. A total of 107 Actinomycetes were isolated and screening was done using modified agar disc diffusion method of which only 39 (36.4%) showed antimicrobial activity against five of the six test isolates that included reference strains Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Candida albicans (ATCC 90028) and three clinical strains Trichophyton mentagrophyte, Microsporum gypseum and Methicillin Resistant Staphylococcus aureus. Two of the isolates showed activity against MRSA and four isolates showed a higher potency than the standard drug Chloramphenicol (30 μg) against S. aureus. Most of the isolates (41.0%) also showed good antimicrobial activity against T. mentagrophyte, though they lower than the control drug Itraconazole (2 μg/ml), they were statistically significant. DNA from the isolates was extracted and the 16S rRNA gene was amplified using primers specific for Actinomycetes. The amplified gene was sequenced and phylogeny analysis was done. The 16S rRNA gene was able to be amplified in only 15 of these isolates. Sequencing showed that 93.3% were of the genus Streptomyces while 6.7% were of the genus Rhodococcus. From the results, the soils from this region harbour Actinomycetes that may have good potential of producing novel antibiotics against gram positive bacteria and dermatophytes.展开更多
Objective:To assess the antimicrobial susceptibility pattern of ESKAPE pathogens from Neyshabur,Iran during 2013-2015.Methods:A total of 345 isolates including 62 Staphylococcus aureus(S.aureus),38 Enterobacter spp.(i...Objective:To assess the antimicrobial susceptibility pattern of ESKAPE pathogens from Neyshabur,Iran during 2013-2015.Methods:A total of 345 isolates including 62 Staphylococcus aureus(S.aureus),38 Enterobacter spp.(including 14 Enterobacter agglomerans,6 Enterobacter aerogenes and other 18 Enterobacter spp.),123 Enterococcus faecium,78 Klebsiella pneumonia,10 Pseudomonas aeruginosa and 34 Acinetobacter baumannii were isolated.The antimicrobial susceptibility pattern of isolates was conducted with Kirby Bauer method.Data were analyzed with SPSS 20.0 software using F-and t-tests.Results:Among S.aureus isolates,the highest resistance was observed against nalidixic acid(81.35%)and cefixime(74.50%).Thirty-three(53.22%)S.aureus isolates were cefoxitin resistant(methicillin-resistant S.aureus).The majority of Enterobacter species was resistant to amikacin(100.00%)and cephalotin(66.60%).Most Enterococcus faecium isolates were resistant to nalidixic acid(89.43%)and amikacin(83.33%),but vancomycin-resistant enterococci isolates were not detected.Moreover,among Klebsiella pneumonia,the highest resistance was observed to nalidixic acid(20.98%)and cotrimoxazole(28.39%).Furthermore,all Pseudomonas aeruginosa isolates were resistant to cefotaxime(100.00%)and majority to nitroforantoin(88.80%).Acinetobacter baumannii isolates showed the highest and the lowest resistance to cefotaxime(100.00%)and cefixime(88.71%),respectively.Conclusions:The prevalence of ESKAPE pathogens from northeast region was low,but majority of them exhibited high rate of antibiotic resistance to common used antimicrobial agents.展开更多
Objective:To evaluate antibacterial sensitivity of 43 ethnomedicinally important plants belonging to 25 different families from Western Uttar Pradesh,a northern province in India,against hospital isolated pathogenic s...Objective:To evaluate antibacterial sensitivity of 43 ethnomedicinally important plants belonging to 25 different families from Western Uttar Pradesh,a northern province in India,against hospital isolated pathogenic strains of Staphylococcus aureus(S.aureus).Methods:Methanol(MeOH)and aqueous extracts of plants were subjected to sensitivity test against S.aureus ATCC 25953 and two hospital isolated virulent strains of S.aureus SA1 and SA2 following disc diffusion assay to determine sensitivity and agar dilution method to test minimum inhibition concentration using Mueller-Hinton agar.Results:Potential antibacterial activity was recorded for MeOH extracts against test pathogens,while moderate antibacterial activity was observed in case of aqueous extracts.Out of 43 plant species,39 species were found sensitive to tested strains.Minimum inhibition concentration values of MeOH extracts were demonstrated at low concentration ranging from 15.5 mg/mL up to 45.5 mg/mL compared to aqueous extracts which were observed ranging from 30.0 mg/mL up to 95.0 mg/mL.Conclusions:The present findings strongly support traditional uses of these plants in the treatment of infectious maladies and further urge of phytochemical and pharmacological research to develop safer and cheaper drugs for the benefit of ailing humanity.展开更多
Objective:To investigate the potential antibacterial activities of ethanol extracts of Turbinaria ornata(T.ornata),Oleic acid(OA)and palmitic acid(PA)extracted from T.ornata as well as mixtures of OA and PA(1:1)agains...Objective:To investigate the potential antibacterial activities of ethanol extracts of Turbinaria ornata(T.ornata),Oleic acid(OA)and palmitic acid(PA)extracted from T.ornata as well as mixtures of OA and PA(1:1)against some bacterial species.Methods:Brown seaweed T.ornata was collected from Hurghada shores,Red Sea coast of Egypt.OA and PA were extracted from T.ornata.Ethanol extracts of T.ornata,OA,PA and mixtures of these two fatty acids(1:1)were tested for their antibacterial activities against Escherichia coli,Bacillus cereus,Bacillus subtilis,Klebsiella pneumonia and Staphylococcus aureus by the disc diffusion method.Results:Ethanol extracts of T.ornata,OA,PA and mixtures of OA and PA(1:1)showed antibacterial activities that increased significantly(least significant difference at 0.05 level)with increasing concentrations against all tested bacteria.Different concentrations of ethanol extracts of T.ornata and extracted OA showed its highest activity against Bacillus subtilis,while PA and mixtures of PA and OA(1:1)showed its highest activity against Bacillus cereus.The maximum inhibition activities were shown for mixtures of OA and PA(1:1).Scanning electron microscope showed that mixtures of OA and PA(1:1)caused plasmolysis and reduction in cell size of Escherichia coli.Conclusions:Different concentrations of T.ornata and its fatty acids showed activities against all tested bacteria.Therefore,it is a potential source of natural antimicrobial compounds.展开更多
Objective:To examine hypoglycemic and antibacterial activity against some Gram-positive and Gram-negative bacteria of organic extracts of four Bangladeshi plants.Methods:An in vivo hypoglycemic effect on mice model wa...Objective:To examine hypoglycemic and antibacterial activity against some Gram-positive and Gram-negative bacteria of organic extracts of four Bangladeshi plants.Methods:An in vivo hypoglycemic effect on mice model was used to check the hypoglycemic effect of four Bangladeshi herbal organic extracts viz.,roots of Curculigo recurvata W.T.Aiton(Satipata)(C.recurvata),leaf of Amorphophallus bulbifer Roxb.(Olkachu)(A.bulbifer),whole plant of Thunbergia grandiflora Roxb.(Nillata)(T.grandiflora)and leaf of Steudnera colocasiifolia K.Koch(Yunnan)(S.colocasiifolia)using glibenclamide as a positive control and water as a negative control.They were also tested for antibacterial activity on three Grampositive and four Gram-negative bacteria by disk diffusion method.C.recurvata,A.bulbifer and T.grandiflora were extracted with methanol and S.colocasiifolia was extracted with ethanol.Results:Among all the plant extract,only ethanol extract of S.colocasiifolia leaves at 800 mg/kg dose significantly(P<0.01)reduced fasting glucose level in normal mice as compared to standard drug glibenclamide(5 mg/kg).Ethanol extract of S.colocasiifolia leaves at 800 mg/kg dose decreased 20.28%of blood glucose level after 2 h of administration in normal mice,where glibenclamide decreased 39.63%.Methanol extract of T.grandiflora didn’t show any zone of inhibition against the tested bacteria,but other three extracts showed a wide range of zone of inhibition.However,none of the extract showed antibacterial activity against all the tested bacteria.Methanol extract of C.recurvata showed maximum zone of inhibition against Bacillus cereus[(10.50±0.50)mm],Salmonella typhi[(16.20±1.26)mm],Escherichia coli[(13.00±1.00)mm]and ethanol extract of S.colocasiifolia showed maximum zone of inhibition against Staphylococcus aureus[(11.20±1.26)mm],Bacillus subtilis[(12.00±0.50)mm],Salmonella paratyphi[(10.80±0.29)mm].Only methanol extract of A.bulbifer showed(8.50±0.50)mm and(7.20±0.76)mm zone of inhibition against Pseudomomas aeruginosa at 1000 and 800�展开更多
Objective:To detect extended spectrumβ-lactamase(ESBL)and determine its prevalence in various clinical samples collected from Dehradun City Hospital.Methods:The samples were first cultured in MacConkey’s agar plates...Objective:To detect extended spectrumβ-lactamase(ESBL)and determine its prevalence in various clinical samples collected from Dehradun City Hospital.Methods:The samples were first cultured in MacConkey’s agar plates by streak plate method,then identified by Gram staining and biochemical tests.The isolated bacterial strains were then tested for antibiotic susceptibility by Kirby-Bauer method.The ESBL detection is then carried out by double disc diffusion method.Results:Off the 56 samples cultured,21 strains were identified which were six Escherichia coli(E.coli),six Klebsiella,four Proteus,four Pseudomonas aeruginosa(P.aeruginosa)and only one Acinetobacter.Eight out of 21(38.1%)strains including three of E.coli,three of Klebsiella and two of P.aeruginosa,were found to be resistance to all five antibiotics(piperacillin,amikacin,ampicillin,gentamicin,and ciprofloxacin).Initial screening using four antibiotics(cefotaxime,ceftazidime,aztreonam and ceftriaxone)and the final confirmatory test using ceftazidime/clavulanic acid and ceftazidime alone showed that 19.05%of all strains isolated were ESBL producers.Individually,16.67%E.coli,16.67%Klebsiella pneumoniae,25%P.aeruginosa and 100%Acinetobacter were found to be ESBL producers.Conclusions:Antibiotic resistance by ESBL has become a major risk factor worldwide,therefore routine checkup and accordingly prescription are suggested.展开更多
Objective:To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria,as most of the pathogens develop drug resistance against comm...Objective:To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria,as most of the pathogens develop drug resistance against commonly used antibiotics.Methods:Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance.Extraction of bioactive principles was done with water and ethanol.Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains.Results:Of the 6 different plant materials tested,extracts prepared from Psidium guajava leaves showed significantly higher efficacy.Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts.Conclusions:The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity,and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment,management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district,Tamilnadu,India.展开更多
Objective:To evaluate the antioxidant and antimicrobial activity of methanolic extract extracts of selected Algerian medicinal plants.Methods:Antioxidant activity of extracts was evaluated in terms of radical scavengi...Objective:To evaluate the antioxidant and antimicrobial activity of methanolic extract extracts of selected Algerian medicinal plants.Methods:Antioxidant activity of extracts was evaluated in terms of radical scavenging potential(2,2-diphenyl-1-picrylhydrazyl)and β-carotene bleaching assay.Total phenolic contents and flavonoid contents were also measured.Antimicrobial activity of these plants was examined against Bacillus subtilis,Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa and Candida albicans.Results:The values of IC_(50) ranged from 4.30μg/mL to 486.6μg/mL for the DPPH method,while total antioxidant activity using β-carotene/linoleic acid bleaching assay ranged from 17.03%to 86.13%.It was found that Pistacia lentiscus showed the highest antioxidant capacities using DPPH assay(IC_(50)=4.30μg/mL),while Populus trimula,Origanum glandulosum,Centaurea calcitrapa,Sysimbrium officinalis and Rhamnus alaternus showed the highest percent of total antioxidant activity in β-carotene/linoleic acid bleaching assay.Total phenolic and flavonoid contents ranged from 3.96 to 259.65 mg GAE/g extract and from 1.13 to 26.84 mg QE/g extract,respectively.The most interesting antimicrobial activity was obtained from Sysimbrium officinalis,Rhamnus alaternus,Origanum glandulosum,Cupressus sempervirens,Pinus halipensis and Centaurea calcitrapa.Conclusions:The results indicated that the plants tested may be potential sources for isolation of natural antioxidant and antimicrobial compounds.展开更多
文摘Objective To identify the antimicrobial resistance of commercial lactic acid bacteria present in microbial foods and drug additives by analyzing their isolated strains used for fermentation and probiotics. Methods Antimicrobial susceptibility of 41 screened isolates was tested with disc diffusion and E-test methods after species-level identification. Resistant strains were selected and examined for the presence of resistance genes by PCR. Results Distribution of resistance was found in different species. All isolates were susceptible to chloramphenicol, tetracycline, ampicillin, amoxicillin/clavulanic acid, cephalothin, and imipenem. In addition, isolates resistant to vancomycin, rifampicin, streptomycin, bacitracin, and erythromycin were detected, although the incidence of resistance to these antibiotics was relatively low. In contrast, most strains were resistant to ciprofloxacin, amikacin, trimethoprim/sulphamethoxazole, and gentamycin. The genes msrC, vanX, and dfrA were detected in strains of Enterococcus faecium, Lactobacillus plantarum, Streptococcus thermophilus, and Lactococcus lactis. Conclusion Antibiotic resistance is present in different species of probiotic strains, which poses a threat to food safety. Evaluation of the safety of lactic acid bacteria for human consumption should be guided by established criteria, guidelines and regulations.
文摘Objective:To investigate the antibacterial and cytotoxic activity of fourteen different edible vegetables methanolic extract from Bangladesh.Methods:The antibacterial activity was evaluated using disc diffusion assay method against 12 bacteria(both gram positive and gram negative).The plant extracts were also screened for cytotoxic activity using the brine shrimp lethality bioassay method and the lethal concentrations(LC_(50))were determined at confidence intervals by analyzing the data on a computer loaded with"Finney Programme??Results:All the vegetable extracts showed low to elevated levels of antibacterial activity against most of the tested strains(zone of inhibition=5-28 mm).The most active extract against all bacterial strains was from Xanthium indicum which showed remarkable antibacterial activity having the diameter of growth inhibition zone ranging from 12 to 28 mm followed by Alternanthera sessilis(zone of inhibition=6-21 mm).All extracts exhibited considerable general toxicity towards brine shrimps.The LC_(50)value of the tested extracts was within the range of 8.447 to 60.323μg/mL with respect to the positive control(vincristine sulphate)which was 0.91μg/mL.Among all studied extracts,Xanthium indicum displayed the highest cytotoxic effect with LC_(50)value of 8.447μg/mL.Conclusions:The results of the present investigation suggest that most of the studied plants are potentially good source of antibacterial and anticancer agents.
文摘A rotating disc column (RDC) with inner diameter 68 mm and 28 compartments is used in this study. Parameters including Sauter mean diameter, hold-up and mass transfer coefficient are measured experimentally un-der different operating conditions. The correlations in literature for molecular diffusion and enhancement factor equation including eddy diffusion, circulation and oscillation of drops are evaluated. A new equation for the effec-tive diffusion coefficient as a function of Reynolds number is proposed. The calculated values of mass transfer co-efficient and column height from the previous equations and present equation are compared with the experimental data. The results from the present equation are in very good agreement with the experimental results, which may be used in designing RDC columns.
文摘Camellia sinensis Linn is a well-known medical herb that grows in various parts of the world. In the current study, the antimicrobial activity of methanol extract from C. sinensis leaves against Lactococcus garvieae and Aeromanas hydrophila isolated from rainbow trout (Oncorhynchus mykiss) was investigated. The growth inhibitory effects of green tea extract was determined by disc diffusion method (3 times on different days), minimum inhibitory concentration (MIC) using serial dilution and minimum bactericidal concentration (MBC). For the L. garvieae and A. hydrophila, the zone diameter inhibition (ZDI) of extract ranged 2.30 - 16.5 mm. The highest ZDI (16.50 ± 1.12 mm) for L. garvieae was observed at 100 mg•ml-1 and for A. hydrophila (16.20 ± 0.95 mm) at 250 mg•ml-1 concentration of green tea extract (P •ml-1 concentrations of extract, ZDI values of A. hydrophila and L. garvieae showed significant difference (P < 0.05). The lowest MIC value for the extract was 0.8 mg•ml-1 against both L. garvieae and A. hydrophila. From the results of the present study, it can be concluded that methanol extract of C. sinenses leaves could be effective for the inhibition of A. hydrophila and L. garvieae in rainbow trout.
基金Supported by Outright Research Grant(Project No.151516PNSE)the Natural Sciences Research Institute
文摘Objective: To determine the bioactive phytochemicals and antimicrobial activity of leaf and stem ethanolic extracts from Muntingia calabura L.(M. calabura).Methods: Dried leaves and stems of M. calabura were extracted with 95% ethanol. The antibacterial and antifungal activities of the extracts were examined using the disc diffusion assay. The minimum inhibitory concentration(MIC) of each extract showing antimicrobial activity was determined. The dried extracts were subjected to phytochemical screening to determine the presence of bioactive components. Total phenolic and flavonoid contents were also determined by the Folin–Ciocalteu method and the aluminum chloride method, respectively.Results: Varying degrees of antimicrobial activity were exhibited by the leaf and stem extracts against Pseudomonas aeruginosa(P. aeruginosa), Salmonella typhimurium,Staphylococcus aureus(S. aureus), Bacillus subtilis, and Candida albicans(C. albicans),with minimal activity against Escherichia coli. Based on the MIC, the extracts showed the highest activity against C. albicans, S. aureus and P. aeruginosa. Phytochemical screening revealed the presence of sterols, flavonoids, alkaloids, saponins, glycosides and tannins in the leaf extract; however, no triterpenes were detected. In the stem extract,triterpenes were detected along with relative amounts of flavonoids, saponins, glycosides and tannins. Alkaloids and sterols were absent in the stem extract.Conclusions: M. calabura leaf and stem ethanol extracts are potential sources of antibacterial agents against P. aeruginosa and S. aureus. This study reports for the first time the high degree of antifungal activity of M. calabura ethanolic extract, especially against C. albicans.
基金Supported by“Operational Program Prague–Competitiveness”(CZ.2.16/3.1.00/24503)the“National Program of Sustainability I”-NPU I(LO1601-No.:MSMT-43760/2015)from the University of Chemistry and Technology,Czech Republic
文摘Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts(petroleum ether, ethanol and water) prepared from some fungal mycelia.Methods: Seven fungal mycelia were prepared, initially extracted with acidified ethanol(0.2 mol/L HCl in 80% ethanol), yielding the raw crude extracts. The obtained extracts were then further partitioned with petroleum ether(F1), ethanol(F2) and water(F3). All the fractions were tested for antimicrobial activity using the disc diffusion assay.Results: Our data showed that all the fractions could inhibit the testing bacteria.However, the inhibitory activity was found to be dependent on(i) the fungal strains used;(ii) the solvent extracted; and(iii) the testing bacteria assayed. In general, the ethanolic extracts(F2) derived from all fungi displayed highest inhibitory activity against the testing bacteria except for Chaetomium sp.Conclusions: The findings of the present study concluded that the extracts prepared from the fungal mycelia had the bioactive compounds with antibacterial property. This study is a pioneering work and further study should be carried out for development of the new drug leads.
文摘Antimicrobial drug resistance is a rising concern in the treatment of infectious diseases and necessitates the need for discovery of novel, potent antimicrobial compounds to combat antibiotic resistance. Since natural environment remains a potential source of novel antimicrobial products, this preliminary study was performed to test the potential of soils from Kericho County for antibiotic-producing Actinomycetes. Soil samples (214) were randomly collected from virgin soils of Kipkelion East, Kipkelion West, Belgut, Ainamoi, Sigowet and Bureti sub-counties in Kericho County from a depth of between 11 cm - 16 cm from the surface of the soil profile. A total of 107 Actinomycetes were isolated and screening was done using modified agar disc diffusion method of which only 39 (36.4%) showed antimicrobial activity against five of the six test isolates that included reference strains Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922) and Candida albicans (ATCC 90028) and three clinical strains Trichophyton mentagrophyte, Microsporum gypseum and Methicillin Resistant Staphylococcus aureus. Two of the isolates showed activity against MRSA and four isolates showed a higher potency than the standard drug Chloramphenicol (30 μg) against S. aureus. Most of the isolates (41.0%) also showed good antimicrobial activity against T. mentagrophyte, though they lower than the control drug Itraconazole (2 μg/ml), they were statistically significant. DNA from the isolates was extracted and the 16S rRNA gene was amplified using primers specific for Actinomycetes. The amplified gene was sequenced and phylogeny analysis was done. The 16S rRNA gene was able to be amplified in only 15 of these isolates. Sequencing showed that 93.3% were of the genus Streptomyces while 6.7% were of the genus Rhodococcus. From the results, the soils from this region harbour Actinomycetes that may have good potential of producing novel antibiotics against gram positive bacteria and dermatophytes.
基金Supported by Medical Diagnostic Laboratory of Neyshabour,Center of Medical,Pathological and Genetic Diagnostic Services,Iranian Academic Center for Education,Culture and Research(ACECR),Mashhad Branch,Mashhad,Iran(Grant No.1393/247N58).
文摘Objective:To assess the antimicrobial susceptibility pattern of ESKAPE pathogens from Neyshabur,Iran during 2013-2015.Methods:A total of 345 isolates including 62 Staphylococcus aureus(S.aureus),38 Enterobacter spp.(including 14 Enterobacter agglomerans,6 Enterobacter aerogenes and other 18 Enterobacter spp.),123 Enterococcus faecium,78 Klebsiella pneumonia,10 Pseudomonas aeruginosa and 34 Acinetobacter baumannii were isolated.The antimicrobial susceptibility pattern of isolates was conducted with Kirby Bauer method.Data were analyzed with SPSS 20.0 software using F-and t-tests.Results:Among S.aureus isolates,the highest resistance was observed against nalidixic acid(81.35%)and cefixime(74.50%).Thirty-three(53.22%)S.aureus isolates were cefoxitin resistant(methicillin-resistant S.aureus).The majority of Enterobacter species was resistant to amikacin(100.00%)and cephalotin(66.60%).Most Enterococcus faecium isolates were resistant to nalidixic acid(89.43%)and amikacin(83.33%),but vancomycin-resistant enterococci isolates were not detected.Moreover,among Klebsiella pneumonia,the highest resistance was observed to nalidixic acid(20.98%)and cotrimoxazole(28.39%).Furthermore,all Pseudomonas aeruginosa isolates were resistant to cefotaxime(100.00%)and majority to nitroforantoin(88.80%).Acinetobacter baumannii isolates showed the highest and the lowest resistance to cefotaxime(100.00%)and cefixime(88.71%),respectively.Conclusions:The prevalence of ESKAPE pathogens from northeast region was low,but majority of them exhibited high rate of antibiotic resistance to common used antimicrobial agents.
基金Supported by SERC Fast Track OYS Scheme,Department of Science and Technology,New Delhi,India[Grant No.304/2004(SR/FT/L-129/2004)].
文摘Objective:To evaluate antibacterial sensitivity of 43 ethnomedicinally important plants belonging to 25 different families from Western Uttar Pradesh,a northern province in India,against hospital isolated pathogenic strains of Staphylococcus aureus(S.aureus).Methods:Methanol(MeOH)and aqueous extracts of plants were subjected to sensitivity test against S.aureus ATCC 25953 and two hospital isolated virulent strains of S.aureus SA1 and SA2 following disc diffusion assay to determine sensitivity and agar dilution method to test minimum inhibition concentration using Mueller-Hinton agar.Results:Potential antibacterial activity was recorded for MeOH extracts against test pathogens,while moderate antibacterial activity was observed in case of aqueous extracts.Out of 43 plant species,39 species were found sensitive to tested strains.Minimum inhibition concentration values of MeOH extracts were demonstrated at low concentration ranging from 15.5 mg/mL up to 45.5 mg/mL compared to aqueous extracts which were observed ranging from 30.0 mg/mL up to 95.0 mg/mL.Conclusions:The present findings strongly support traditional uses of these plants in the treatment of infectious maladies and further urge of phytochemical and pharmacological research to develop safer and cheaper drugs for the benefit of ailing humanity.
基金Supported by a grant from the Department of Botany and Microbiology,Damietta University,Damietta,Egypt as a part of MSc programme(Grant No.110/2012).
文摘Objective:To investigate the potential antibacterial activities of ethanol extracts of Turbinaria ornata(T.ornata),Oleic acid(OA)and palmitic acid(PA)extracted from T.ornata as well as mixtures of OA and PA(1:1)against some bacterial species.Methods:Brown seaweed T.ornata was collected from Hurghada shores,Red Sea coast of Egypt.OA and PA were extracted from T.ornata.Ethanol extracts of T.ornata,OA,PA and mixtures of these two fatty acids(1:1)were tested for their antibacterial activities against Escherichia coli,Bacillus cereus,Bacillus subtilis,Klebsiella pneumonia and Staphylococcus aureus by the disc diffusion method.Results:Ethanol extracts of T.ornata,OA,PA and mixtures of OA and PA(1:1)showed antibacterial activities that increased significantly(least significant difference at 0.05 level)with increasing concentrations against all tested bacteria.Different concentrations of ethanol extracts of T.ornata and extracted OA showed its highest activity against Bacillus subtilis,while PA and mixtures of PA and OA(1:1)showed its highest activity against Bacillus cereus.The maximum inhibition activities were shown for mixtures of OA and PA(1:1).Scanning electron microscope showed that mixtures of OA and PA(1:1)caused plasmolysis and reduction in cell size of Escherichia coli.Conclusions:Different concentrations of T.ornata and its fatty acids showed activities against all tested bacteria.Therefore,it is a potential source of natural antimicrobial compounds.
基金Supported by Department of Pharmacy,International Islamic University Chittagong,Bangladesh with a research grant to accomplish the study(Grant No.Pharm-P&D 71/09-15/09).
文摘Objective:To examine hypoglycemic and antibacterial activity against some Gram-positive and Gram-negative bacteria of organic extracts of four Bangladeshi plants.Methods:An in vivo hypoglycemic effect on mice model was used to check the hypoglycemic effect of four Bangladeshi herbal organic extracts viz.,roots of Curculigo recurvata W.T.Aiton(Satipata)(C.recurvata),leaf of Amorphophallus bulbifer Roxb.(Olkachu)(A.bulbifer),whole plant of Thunbergia grandiflora Roxb.(Nillata)(T.grandiflora)and leaf of Steudnera colocasiifolia K.Koch(Yunnan)(S.colocasiifolia)using glibenclamide as a positive control and water as a negative control.They were also tested for antibacterial activity on three Grampositive and four Gram-negative bacteria by disk diffusion method.C.recurvata,A.bulbifer and T.grandiflora were extracted with methanol and S.colocasiifolia was extracted with ethanol.Results:Among all the plant extract,only ethanol extract of S.colocasiifolia leaves at 800 mg/kg dose significantly(P<0.01)reduced fasting glucose level in normal mice as compared to standard drug glibenclamide(5 mg/kg).Ethanol extract of S.colocasiifolia leaves at 800 mg/kg dose decreased 20.28%of blood glucose level after 2 h of administration in normal mice,where glibenclamide decreased 39.63%.Methanol extract of T.grandiflora didn’t show any zone of inhibition against the tested bacteria,but other three extracts showed a wide range of zone of inhibition.However,none of the extract showed antibacterial activity against all the tested bacteria.Methanol extract of C.recurvata showed maximum zone of inhibition against Bacillus cereus[(10.50±0.50)mm],Salmonella typhi[(16.20±1.26)mm],Escherichia coli[(13.00±1.00)mm]and ethanol extract of S.colocasiifolia showed maximum zone of inhibition against Staphylococcus aureus[(11.20±1.26)mm],Bacillus subtilis[(12.00±0.50)mm],Salmonella paratyphi[(10.80±0.29)mm].Only methanol extract of A.bulbifer showed(8.50±0.50)mm and(7.20±0.76)mm zone of inhibition against Pseudomomas aeruginosa at 1000 and 800�
文摘Objective:To detect extended spectrumβ-lactamase(ESBL)and determine its prevalence in various clinical samples collected from Dehradun City Hospital.Methods:The samples were first cultured in MacConkey’s agar plates by streak plate method,then identified by Gram staining and biochemical tests.The isolated bacterial strains were then tested for antibiotic susceptibility by Kirby-Bauer method.The ESBL detection is then carried out by double disc diffusion method.Results:Off the 56 samples cultured,21 strains were identified which were six Escherichia coli(E.coli),six Klebsiella,four Proteus,four Pseudomonas aeruginosa(P.aeruginosa)and only one Acinetobacter.Eight out of 21(38.1%)strains including three of E.coli,three of Klebsiella and two of P.aeruginosa,were found to be resistance to all five antibiotics(piperacillin,amikacin,ampicillin,gentamicin,and ciprofloxacin).Initial screening using four antibiotics(cefotaxime,ceftazidime,aztreonam and ceftriaxone)and the final confirmatory test using ceftazidime/clavulanic acid and ceftazidime alone showed that 19.05%of all strains isolated were ESBL producers.Individually,16.67%E.coli,16.67%Klebsiella pneumoniae,25%P.aeruginosa and 100%Acinetobacter were found to be ESBL producers.Conclusions:Antibiotic resistance by ESBL has become a major risk factor worldwide,therefore routine checkup and accordingly prescription are suggested.
文摘Objective:To evaluate the antimicrobial potentials of 6 traditionally used medicinal plants to treat gastrointestinal infection against pathogenic bacteria,as most of the pathogens develop drug resistance against commonly used antibiotics.Methods:Crude extracts from different parts of different plants were tested against bacterial strains of clinical significance.Extraction of bioactive principles was done with water and ethanol.Evaluation of antibacterial activity was done by disc diffusion assay against selected bacterial stains.Results:Of the 6 different plant materials tested,extracts prepared from Psidium guajava leaves showed significantly higher efficacy.Extracts prepared using alcohol exhibited higher antibacterial activity when compared to their corresponding aqueous extracts.Conclusions:The findings of the present study suggested that phytochemical extracts of the presently studied plant materials possess significant anti-enteric bacterial activity,and thus lend pharmacological credibility to the suggested traditional use of the plant as a natural remedy for the treatment,management and/or control of gastrointestinal diseases in the coastal tracts of Kanyakumari district,Tamilnadu,India.
基金Supported by Algerian Ministry of Higher Education and Scientific Research.
文摘Objective:To evaluate the antioxidant and antimicrobial activity of methanolic extract extracts of selected Algerian medicinal plants.Methods:Antioxidant activity of extracts was evaluated in terms of radical scavenging potential(2,2-diphenyl-1-picrylhydrazyl)and β-carotene bleaching assay.Total phenolic contents and flavonoid contents were also measured.Antimicrobial activity of these plants was examined against Bacillus subtilis,Staphylococcus aureus,Escherichia coli,Pseudomonas aeruginosa and Candida albicans.Results:The values of IC_(50) ranged from 4.30μg/mL to 486.6μg/mL for the DPPH method,while total antioxidant activity using β-carotene/linoleic acid bleaching assay ranged from 17.03%to 86.13%.It was found that Pistacia lentiscus showed the highest antioxidant capacities using DPPH assay(IC_(50)=4.30μg/mL),while Populus trimula,Origanum glandulosum,Centaurea calcitrapa,Sysimbrium officinalis and Rhamnus alaternus showed the highest percent of total antioxidant activity in β-carotene/linoleic acid bleaching assay.Total phenolic and flavonoid contents ranged from 3.96 to 259.65 mg GAE/g extract and from 1.13 to 26.84 mg QE/g extract,respectively.The most interesting antimicrobial activity was obtained from Sysimbrium officinalis,Rhamnus alaternus,Origanum glandulosum,Cupressus sempervirens,Pinus halipensis and Centaurea calcitrapa.Conclusions:The results indicated that the plants tested may be potential sources for isolation of natural antioxidant and antimicrobial compounds.