Diameter Of Growth Inhibition Zone Research Articles

In vitro antibacterial effect of a nano-zinc oxide eugenol sealer alone and in combination with chitosan, propolis, and nanosilver on Enterococcus faecalis

ABSTRACT Background: This study aimed to assess the antibacterial effect of a nano-zinc oxide eugenol (nZOE) sealer alone and in combination with chitosan, propolis, and nanosilver on Enterococcus faecalis. Materials and Methods: In this in vitro, experimental study, nanosilver, chitosan, and propolis with 10wt%, 20wt%, and 60wt% concentrations, respectively, were added to nZOE sealer, and their antibacterial activity against E. faecalis was evaluated by agar diffusion and broth microdilution tests. The diameter of the growth inhibition zones was measured, and the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were calculated for all materials. Data were analyzed by t-test (alpha = 0.05). Results: The addition of nanosilver, chitosan, and propolis to nZOE did not change the diameter of growth inhibition zone in agar diffusion test. Propolis and eugenol alone showed the lowest MIC and MBC. Chitosan alone showed the highest MIC and MBC. Furthermore, nZOE showed lower MBC than micro-ZOE (P = 0.000). All groups containing nZOE showed the lowest MIC and MBC values. Conclusion: The addition of propolis to nZOE can enhance its antibacterial activity against E. faecalis in vitro.

Application of Prebiotics and Probiotics to Improve Oral and Dental Health by Inhibiting Streptococcus mutans

Background: The most common method to combat microorganisms that cause tooth decay is the use of antibiotics. However, despite the benefits of antibiotics, their use has significant disadvantages, such as the increased resistance of microorganisms to these chemicals. Objectives: A promising and safer alternative is the use of probiotics and prebiotics, which can reduce or inhibit the growth of disease-causing oral microorganisms. Streptococcus salivarius is one such probiotic, while inulin and nisin are the prebiotics commonly recommended for this purpose. Methods: Several assays, including agar bilayer interference, agar well penetration, and microdilution, were used to assess the antibacterial activities of S. salivarius K12 and S. salivarius M18 probiotics, as well as those of the prebiotics nisin and inulin. Additionally, bile salt and low pH tolerance assessments were conducted for the probiotics, and the synthesis of bacteriocins by the probiotics was verified using proteolytic and enzymatic activity assays. Results: The minimum inhibitory concentration (MIC) assay revealed that Streptococcus mutans growth was inhibited by S. salivarius K12 and S. salivarius M18 at a concentration of 75%, and by nisin and inulin at 200 IU/mL. In the well penetration assay, S. salivarius K12 exhibited significantly better results compared to S. salivarius M18. Nisin had significantly greater inhibitory effects on S. mutans compared to inulin. A combination of all four components (S. salivarius K12, S. salivarius M18, nisin, and inulin) resulted in maximum antibacterial activity, indicating a synergistic effect. Based on the agar bilayer assay and the growth inhibition zone diameters, nisin showed the highest antibacterial activity against S. mutans, followed by S. salivarius K12, inulin, and S. salivarius M18. Enzymatic digestion and proteolytic activity assays confirmed the synthesis of bacteriocins by S. salivarius K12 and S. salivarius M18. Both probiotics demonstrated bile salt tolerance at a concentration of 0.3% and surviving rates of 36% and 33%, respectively, at pH 2. Conclusions: The most important finding of the current study is the synergistic effect between the highlighted prebiotics and probiotics, which may offer a novel and effective combination for preventing tooth decay.

Investigation into the impact of certain leaf extracts derived from Inula viscosa L. on various strains of pathogenic bacteria in poultry

The study was designed to investigate the efficacy of acetone, ethanol, hexane, diethyl ether, and aqueous extracts from clay plants against four pathogenic bacteria commonly found in poultry: Escherichia coli, Streptococcus aureus, Pseudomonas aeruginosa, and Clostridium perfringens. The research took place in the microbiology and drug laboratories of the Faculty of Pharmacy at the University of Tartous, as well as the microbiology laboratory at the Faculty of Agricultural Engineering at Tishreen University. Tayon plant leaves were harvested in October and November of 2021 from the Safita region, dried, and stored for future use. The susceptibility tests were carried out on the four bacteria under investigation using the five different extracts. The findings revealed that Escherichia coli, Streptococcus aureus, Pseudomonas aeruginosa, and Clostridium perfringens were all impacted by the extracts, except for Escherichia coli which displayed resistance to acetone, ethanol, hexane, and diethyl ether extracts, but not to the aqueous extract. Pseudomonas aeruginosa also exhibited resistance to the diethyl ether extract at concentrations of 20 and 40 μl, with no inhibition zone observed. At a concentration of 80 μl, the largest average diameter of the bacterial growth inhibition zone was observed for the acetone extract (4.82, 24.95, 15.41, and 22.14 mm), ethanol (9.32, 28.11, 22.98, and 29.24 mm), hexane (6.42, 18.91, 13.23, and 17.47 mm), diethyl ether (9.33, 21.22, 9.56, and 18.75 mm), and aqueous extract (23.45, 26.22, 15.71, and 24.12 mm), respectively, in comparison to concentrations of 20 and 40 microliters and the control. These results suggest that the plant leaf extracts possess antimicrobial properties against the pathogenic bacterial strains tested, indicating their potential as natural sources of antibiotics in the future.

Molecular Periphery Design Allows Control of the New Nitrofurans Antimicrobial Selectivity.

A series of 13 new 3-substituted 5-(5-nitro-2-furyl)-1,2,4-oxadiazoles was synthesized from different aminonitriles. All compounds were screened in the disc diffusion test at a 100 μg/mL concentration to determine the bacterial growth inhibition zone presence and diameter, and then the minimum inhibitory concentrations (MICs) were determined for the most active compounds by serial dilution. The compounds showed antibacterial activity against ESKAPE bacteria, predominantly suppressing the growth of 5 species out of the panel. Some compounds had similar or lower MICs against ESKAPE pathogens compared to ciprofloxacin, nitrofurantoin, and furazidin. In particular, 3-azetidin-3-yl-5-(5-nitro-2-furyl)-1,2,4-oxadiazole (2h) inhibited S. aureus at a concentration lower than all comparators. Compound 2e (5-(5-nitro-2-furyl)-3-[4-(pyrrolidin-3-yloxy)phenyl]-1,2,4-oxadiazole) was active against Gram-positive ESKAPE pathogens as well as M. tuberculosis. Differences in the molecular periphery led to high selectivity for the compounds. The induced-fit docking (IFD) modeling technique was applied to in silico research. Molecular docking results indicated the targeting of compounds against various nitrofuran-associated biological targets.

Evaluation of Antimicrobial Properties of Bam Date Kernel Extract and Investigation of the Structure of Extract

Background & Aims: The prevalence of hospital infections, especially of bacterial origin, is increasing and uncontrollable in many countries. Controlling them, because of their damage to the health and economy, is essential. Therefore, numerous efforts have been made to find new antibiotics as suitable alternatives to current ones. This study aimed to investigate the antibacterial activity of date kernel extract against several hospital pathogens. Materials and Methods: Acetone extract of Mozafati date kernel from Bam city was prepared by immersion method and its antibacterial effects on hospital pathogens such as Escherichia coli, Staphylococcus aureus, Salmonella enterica, Pseudomonas aeruginosa, Acinetobacter baumannii were investigated by the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and well diffusion method. Then, the structure of the obtained extract was determined by high-performance liquid chromatography (HPLC). Results: The MIC was observed at 400 mg/mL of extract for S. aureus bacteria. In addition, the MBC of date kernel extract was 500 mg/ mL for the tested bacteria, except for A. baumannii, where a decreasing trend was detected. The antibacterial activity was determined by the well diffusion method against all bacteria, and the greatest activity was observed against S. aureus with a growth inhibition zone diameter of 31 mm. The HPLC analysis showed the presence of 7 different structures, of which rutin was the most abundant. Conclusion: This study indicates the high antibacterial effect of acetone extract of date kernel on the tested bacteria; however, further studies should be conducted on this plant as a new and powerful antibacterial agent.

In vitro Antimicrobial Activity, Antioxidant Activity and Synergistic/Antagonistic Effect of Arum maculatum L. in Mersin Province, Turkey

Arum maculatum is used for the treatment of colitis and internal bleeding haemorrhoids among the local people in Turkey. This study was designed to evaluate the antioxidant and antimicrobial activity and protective effects of the leaf and root methanol extract of Arum maculatum L. The phenolic compound content of the root and leaf extract was determined as 207.135±0.07 µg GAE g-1, and 386.054±0.7 µg GAE g extract-1, respectively. The total flavonoid amount was determined as 53.386±0.220 µg QE g-1 and 347.704±0.352 µg QE g-1 extract, respectively. DPPH free radical scavenging of leaf and root extracts was determined as 76.69% and 67.33%, respectively.. The metal chelating effect was determined as 46.585±0.025 mg EDTA/g extract and 35.610±0.087 mg EDTA g extract-1 for roots and leaves, respectively. All extracts were effective against all tested bacteria, and Staphylococcus mutans ATTC 10449 was the most sensitive bacterium with the lowest MIC value (0.20 mg mL-1, 0.81 mg mL-1) for leaf and root extracts, respectively. The biggest diameter of growth inhibition zone (8±2.44 mm, 9±3.26) compared to Chloramphenicol. Arum leaf extracts showed a synergistic effect with OFX against Escherichia coli and Staphylococcus mutans, and Arum root extracts have a synergistic effect with OFX against Staphylococcus aureus and Staphylococcus mutans. These results displayed that A. maculatum has notable natural bioactive compounds with antioxidant and antibacterial properties.

The chemical composition, in vitro, and in silico studies of Lavandula mairei essential oil

Lavandula mairei is an aromatic, and medicinal plant endemic to Morocco, mainly found in the southeastern region of the Kingdom, and used in traditional medicine for its many benefits. The purpose of the study was to identify the chemical composition of Lavandula mairei essential oil using Gas Chromatography - Tandem Mass Spectrometry, to evaluate the antimicrobial activity of the plant against bacterial strains (Staphylococcus aureus, Staphylococcus aureus MRSA, Enterococcus faecalis, Escherichia coli ATCC 25922, Escherichia coli ESBL, Klebsiella pneumoniae ATCC 700603), and two fungal strains (Aspergillus niger ATCC 10231, Candida albicans ATCC 16404) in order to measure the microbial growth inhibition zone diameter, and to determine the minimum inhibitory, bactericidal, and fungicidal concentration of the essential oil (MIC, MBC, and MFC). Concerning antioxidant activity, six assays (6DPPH, and 1ABTS Free Radical Scavenging Assay, Total Antioxidant Capacity, Hydroxyl Radical, Reducing Power, and β-Carotene Bleaching Inhibition) were performed to determine the antioxidant potential of the essential oil. For the in silico aspect, molecular docking studies were performed to explore the potential interactions of some compounds with five microbial targets (i) Dihydropteroate synthase (1AJ0), ii) The elongation factor EF-Tu (1OB2), iii) d-alanine ligase (2I80), iv) DNA gyrase (2XCT), v) The cytochrome P450 monooxygenase (5V5Z), and 2ADMET prediction analysis was completed on a compound designated as dehydroabietinol. Carvacrol was identified as the major compound (36.38%) by analysis of the chemical composition, E. coli ATCC 25922 (MIC = 1.87 mg/mL ± 0.00, MBC = 15.00 mg/mL ± 0.00), and Enterococcus faecalis (MIC = 0.23 mg/mL ± 0.00, MBC = 5.53 mg/mL ± 2.77) were the most sensitive to the antibacterial treatment, and Candida albicans was resistant to the essential oil. The highest antioxidant potential of the plant was observed in the β-carotene bleaching inhibition test (IC50 = 1.55 mg/mL ± 0.009 and 90 % of inhibition). In the in silico study, the compound dehydroabietinol provided relevant evidence for molecular docking, and this was confirmed by the ADMET prediction analysis. The results of the study were significant, and further experiments will be necessary to find out more about the biological properties of Lavandula mairei.

Exploring non-antimicrobial agents as antibiotic alternatives: an in vitrostudy

Background:Microorganisms cause periapical and pulpal disorders, making root canal treatment (RCT) essential. Due to complex canal anatomy, bacteria may persist despite cleaning. Intracanal medicaments, such as calcium hydroxide and chlorhexidine, help eliminate residual bacteria, reduce inflammation, and enhance treatment outcomes by improving disinfection and compatibility.Aim:To assess the antimicrobial effectiveness of Triple Antibiotic Paste (TAP), Modified TAP, Sertraline (SSRI), Atorvastatin and the combination of Atorvastatin and Sertraline against Enterococcus faecalis.Materials and methods:A total of 30 samples were made, with 6samples from each group: TAP, Sertraline, Atorvastatin, Modified TAP, and Sertraline + Atorvastatin. The antimicrobial efficacy of the medicaments was evaluated using an agar well diffusion test by measuring inhibition zones around the medicaments. Statistical analysis included one-way ANOVA, with significance set at p < 0.05.Results:A significant difference (p=0.001) in the diameter of growth inhibition zones was observed. The maximum inhibitory zone was found in Group 5: Sertraline+Atorvastatin.Conclusion:The combination of sertraline and atorvastatin demonstrated superior antimicrobial efficacy compared to modified TAP, TAP, sertraline, and atorvastatin used alone.

Unveiling the Launaea nudicaulis (L.) Hook medicinal bioactivities: phytochemical analysis, antibacterial, antibiofilm, and anticancer activities.

Commonly used antimicrobial agents are no longer effective due to their overuse or misuse. In addition, many medicinal plant extracts can combat infectious diseases due to their main active constituents or secondary metabolites. The current study aimed to assess the bioactivities of Launaea nudicaulis (LN) leaf extract (LE) against different multi-drug resistant (MDR) Pseudomonas aeruginosa (P. aeruginosa) isolates. The ethyl acetate extract of a Launaea nudicaulis (LN) leaf was analyzed using GC-MS, which identified 27 key bioactive compounds. The major constituents found were as follows: 7-acetyl-6-ethyl-1,1,4,4-tetramethyltetralin, isopropyl myristate, thiocarbamic acid, N,N-dimethyl, S-1,3-diphenyl-2-butenyl ester, hahnfett, cyclopentane acetic acid, 3-oxo-2-pentyl-, methyl ester, hexadecanoic acid, and dotriacontane. Our study demonstrated that the LN leaf was a rich source of other important phytochemicals, including phenolic acids, tannins, saponins, and steroids. The relative biosafety of the L. nudicaulis LE was determined from the elevated inhibitory concentration 50 (IC50) of 262 μg/mL, as calculated from the cytotoxicity assay against the Wi-38 normal cell line. Conversely, 12.7 and 24.5 μg/mL were the recorded low IC50 values for the tested extract against the MCF-7 and Hep-G2 cancerous cell lines, respectively, reflecting its potent activity against the tested cancerous cell lines. Microbiologically, the susceptible P. aeruginosa isolates to the tested extract showed a growth inhibition zone diameter, in the well diffusion assay, ranging from 11.34 ± 0.47 to 26.67 ± 0.47 mm, and a percent inhibition (PI) value of 50-106.2%, reflecting its acceptable activity. In addition, the broth microdilution assay recorded minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) in the ranges of 15.625-1,000 μg/mL and 125-1,000 μg/mL, respectively. In conclusion, the L. nudicaulis LE revealed showed promising activity and high selectivity against P. aeruginosa. Moreover, the extract exhibited natural anticancer activities with safe low concentrations, indicating its potential as a superior candidate for future studies of its active constituents.

ANTIBACTERIAL PROPERTIES OF COMMERCIAL PEPPERMINT ESSENTIAL OIL AGAINST SOME GRAM-POSITIVE AND GRAM-NEGATIVE BACTERIA

The authors of this article conducted research and studied the antibacterial properties of commercial peppermint essential oil (PEO) against several gram-positive and gram-negative bacteria provided by Polish manufacturers of essential oils (Naturalne Aromaty sp. z o.o., Klaj, Poland). Therefore, to conduct research with the aim of to study the antibacterial properties of commercial peppermint essential oil (PEO), an antimicrobial susceptibility test (Kirby-Bauer diffusion test) was used to measure diameters of bacterial growth inhibition zones). In the current study, Gram-negative strains such as Escherichia coli (Migula) Castellani and Chalmers (ATCC® 25922™ ), Escherichia coli (Migula) Castellani and Chalmers (ATCC® 35218™ ), Pseudomonas aeruginosa (Schroeter) Migula (ATCC® 27853™ ) and Gram-positive strains such as Staphylococcus aureus subsp. aureus Rosenbach (ATCC® 29213™ ), methicillin-resistant (MRSA), mecA positive Staphylococcus aureus (NCTC® 12493), Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 51299™ ) (resistant to vancomycin; sensitive to teicoplanin) and Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 29212™ ) were used. Results of the current study revealed that resistant to the PEO were Gram-negative bacterial strains, such as E. coli (Migula) Castellani and Chalmers (ATCC® 35218™ ) and P. aeruginosa (Schroeter) Migula (ATCC® 27853™ ) strains. The authors found that the diameters of the inhibition zones after application of PEO were similar to the control samples (96% ethanol). It was also found that after the application of REO, the increase in the diameters of the inhibition zones was 60.3% (p < 0.05) for the Escherichia coli strain (Migula) Castellani and Chalmers (ATCC® 25922™ ) compared to control samples (96% ethanol ). Accordingly, Gram-positive strains such as S. aureus subsp. aureus Rosenbach (ATCC® 29213™ ) and methicillin-resistant S. aureus (NCTC® 12493) were equally resistant to PEO, similarly. On the other hand, Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 29212™ ) and Enterococcus faecalis (Andrewes and Horder) Schleifer and Kilpper-Balz (ATCC® 51299™ ) were sensitive to PEO. After the application of PEO, the largest diameters of inhibition zones were observed for the E. faecalis strain. The results suggest that commercial peppermint essential oil provided by Polish essential oil manufacturers (Naturalne Aromaty sp. z o.o., Kłaj, Poland) possesses some noteworthy antimicrobial properties. In vivo studies are necessary to calculate the effective dose of EOs and determine their possible side effects and toxicity.

Antimicrobial effects of Cynara scolymus essential oil: In vitro analysis

By benefits of using silicon and vermicompost based biofertilizers and also induction of drought stress for growing more efficient medicinal plants, we investigated such issues on growing Cynara scolymus (C. scolymus), as one of the most significant edible medicinal plants. In this regard, the antimicrobial effects of grown C. scolymus essential oil was investigated against some foodborne pathogens. Different concentrations of silicon and vermicompost with and without drought stress were considered for growing the plant and the extracted essential oils were extracted to examine their antimicrobial effects against different bacterial agents. Using vermicompost and silicon and 50% moisture discharge yielded significant increase in the mean diameter of growth inhibition zone and significant decrease in the minimum inhibitory concentration of tested bacteria (P < 0.05). The highest diameters of the inhibition zones of S. aureus, S. saprophyticus, P. aeruginosa, S. dysenteriae, and S. typhi were found for C. scolymus essential oil treated with 8 mmol silicon and conventional irrigation (14.92 mm), 4 mmol silicon and 50% moisture discharge (15.28 mm), 50% vermicompost and 50% moisture discharge (15.71 mm), 8 mmol silicon and conventional irrigation (17.34 mm) and 25% vermicompost, and 50% moisture discharge (15.48 mm), respectively. Antimicrobial effects of some treatments of C. scolymus were higher than some kinds of referenced antibiotics such as erythromycin. These findings could be used for the production of antibiotic drugs for specific purposes against certain bacteria.

Undecylenic acid and N,N-dibutylundecenamide as effective antibacterials against antibiotic-resistant strains

Evaluation of undecylenic acid (UA) and its tertiary amide N,N-dibutylundecenamide (DBUA) activity­ in vitro against the standard and antibiotic-resistant Escherichia coli and Staphylococcus aureus strains was carried out. The antibacterial potential of the acid and its amide at 2.5 and 5.0 μM concentration both against gram-positive bacteria (S. aureus) and gram-negative (E. coli) cultures was confirmed by monitoring the diameter of the bacterial growth inhibition zones. The docking study identified methionine aminopeptidase (MAP) as the most energy-favorable potential biotarget associated with the drug resistance of E. coli and S. aureus with a binding energy in the range from -8.0 to -8.5 kcal/mol. The ligands complexation was due to the formation of hydrogen bonds with ASP108, HIS171, HIS178, GLU204, GLU235, HIS76, ASP104, GLU233, ASP93 and metal-acceptor interactions with Co2+. Overall, the results indicated that UA and DBUA activity against antibiotic-resistant strains creates prospects for the development of new antibacterial formulations. Keywords: Escherichia coli, methionine aminopeptidase, molecular docking, Staphylococcus aureus, tertiary amide, undecylenic acid

Quinoline Hydrazone Derivatives as New Antibacterials Against Multidrug Resistant Strains.

To develop novel antimicrobial agents a series of 2(4)-hydrazone derivatives of quinoline were designed, synthesized and tested. QSAR models of the antibacterial activity of quinoline derivatives were developed by the OCHEM web platform using different machine learning methods. A virtual set of quinoline derivatives was verified with a previously published classification model of anti-E. coli activity and screened using the regression model of anti-S. aureus activity. Selected and synthesized 2(4)-hydrazone derivatives of quinoline exhibited antibacterial activity against the standard and antibiotic-resistant S. aureus and E. coli strains in the range from 15 to 30 mm by the diameter of growth inhibition zones. Molecular docking showed the complex formation of the studied compounds into the catalytic domain of dihydrofolate reductase with an estimated binding affinity from -8.4 to -9.4 kcal/mol.

The Investigation of the Antibacterial Activity of Eryngium caucasicum trautv, Saponaria officinalis, Froriepia subpinnata, Malva sylvestris, and Urtica dioica

Background: Regarding the increasing resistance of bacteria against antibiotics and the existence of antibacterial compounds in plants, we here investigated the antimicrobial effects of the methanolic extracts of several plants on pathogenic bacteria. Methods: Ten grams of the dry ingredients of Eryngium caucasicum trautv (leaf), Saponaria officinalis (flower), Froriepia subpinnata (leaf), Malva sylvestris (leaf), and Urtica dioica (leaf) was poured in 100 mL of methanol and shaken for 24 hours. After 24 hours, the extracts were strained and dried in the oven, and their antimicrobial activity at the 100 mg/mL concentration was evaluated against the mentioned bacteria using the sinkhole method. Results: The plant extracts inhibited the growth of all bacteria in various degrees. Among all the plant extracts used, that of F. subpinnata delivered the largest diameter of growth inhibition zone (6 mm) against S. dysenteriae, and the extracts of E. caucasicum and F. subpinnata showed the largest diameter of inhibition zone against Xanthomonas translucens. Also, the extract of M. sylvestris delivered the largest inhibition zone diameter (8 mm) against E. coli. Conclusions: Our results showed that the methanolic extract of E. caucasicum was the most effective plant extract against S. dysenteriae, Rathayibacter tritici, and L. monocytogenes, but M. sylvestris extract revealed the greatest impact on E. coli. It is recommended to further investigate the antibacterial compounds of these plants as potential treatments for bacterial infections.

Riverine antibacterial resistance gradient determined by environmental factors.

Polluted waterbodies such as rivers provide a pathway or reservoir for bacterial resistance. We studied water quality and bacterial antibacterial resistance along the subtropical Qishan River in Taiwan as a case study of environmental resistance spread in a pristine rural area. Human settlement densities increased generally from pristine mountain sites to the more polluted lowlands. Accordingly, as a working hypothesis, we expected the antibacterial resistance level to increase downstream. We collected sediment samples from 8 stations along the Qishan river and where the Qishan river reaches the Kaoping river. The samples were processed in the lab for bacteriological and physicochemical analysis. Antibacterial resistance was tested with common antibacterial. A comparison was made among the sites where isolates began to occur at the upstream (sites 1-6) with the downstream, including site 7 (Qishan town), site 8 (wastewater treatment plant), and site 9 (Kaoping river). The results of multivariate analysis for bacteriological and physicochemical parameters showed increasing water pollution levels downstream of the Qishan river. Bacterial isolates including Escherichia coli, Klebsiella pneumoniae, Serratia marcescens, Enterobacter sp., Acinetobacter sp., Staphylococcus spp., and Bacillus spp. were analyzed and tested in the study. Their percentage of occurrence varied at each site. The resistance level was determined from the growth inhibition zone diameter (disk diffusion) and the minimum inhibitory concentration (micro-dilution). The results indicated that antibacterial resistance was related to certain environmental factors. Besides, the usage pattern of different classes of antibacterial in different sections could alter trends of their resistance. Bacteria were found with increased resistance to antibacterial used in agriculture through the downstream sites. The WWTP discharging wastewater was demonstrated to be a hotspot of resistance in aquatic environments. In conclusion, bacterial resistance against antibacterial from the Qishan river has become a potential public health threat. This study could assist authorities by providing a reference for risk assessment and management of water quality in Kaohsiung city and southern Taiwan.

Synthesis of Biogenic Silver Nanoparticles (bAgNPs) Using Leaf Extract of Mirabilis jalapa and Evaluation of Anti-vibriocidal, Anti-oxidant properties and Cytotoxicity

Acute hepatopancreatic necrosis disease (AHPND) and luminescent vibriosis are two major bacterial diseases of penaeid shrimp which are caused by gram-negative pathogenic bacteria Vibrio parahaemolyticus (Vp) and Vibrio harveyi (Vh) respectively. These diseases cause massive mortality and huge economic loss worldwide in shrimp aquaculture. Extensive and inappropriate usage of antibiotics against these pathogens resulted in antibiotic-resistant strains. Drug repurposing appears to be an appropriate solution to eliminate antibiotic resistance in pathogens. In the present study, biogenic silver nanoparticles (bAgNPs) are synthesized by reducing AgNO3 using the aqueous extract of Mirabilis jalapa (MJ) leaves. The anti-oxidant, cytotoxic, and anti-vibriocidal activity of bAgNPs against Vp and Vh are evaluated. The formation of bAgNPs was confirmed by the appearance of a dark brown coloured solution and with a maximum absorption peak at 434 nm. The characterization of bAgNPs using FESEM and EDX, TEM, XRD, FTIR, and DLS has confirmed that the nanoparticles are crystalline and spherical in shape with an approximate diameter of 50 nm and have capping agents. The diameters of microbial growth inhibition zones for Vp and Vh are 26 mm and 23 mm respectively. Further, the MIC values for Vp and Vh are 31.25 µg/mL and 93.75 µg/mL respectively. The DPPH and FRAP assays showed substantial anti-oxidant activity with IC50 values of 67.39 µg/mL and 5.509 µg/mL respectively. MTT assay to check the cytotoxicity effect of bAgNPs on Vero cells resulted in very less toxicity at the maximum concentration tested with an IC50 value of 293.5 µg/mL. Therefore, the bAgNPs synthesized from leaves of MJ showed effective anti-vibriocidal and anti-oxidant properties with negligible cytotoxic effects.

Fabrication, characterisation and antimicrobial activity of electrospun Plantago psyllium L. seed gum/gelatine nanofibres incorporated with Cuminum cyminum essential oil nanoemulsion

SummaryPlantago psyllium L. seed gum (PPSG)/gelatine nanocomposites containing Cuminum cyminum essential oil (CCEO) were prepared via electrospinning, and the antibacterial properties of the electrospun nanofibres were assessed against Staphylococcus aureus. The nanoemulsion was prepared by adding CCEO to the PPSG/gelatine mixture and sonicated. Uniform nanofibres resulted from the nanoemulsion containing 1.5% PPSG, 8% gelatine and 3% CCEO, and no chemical reactions between the components of the electrospun nanofibres were detected. Growth inhibition zone diameter indicated that the electrospun nanofibres containing at least 3% CCEO had the most significant inhibitory effect on the growth of S. aureus. The electrospun PPSG/gelatine‐CCEO nanocomposites are capable of being used as a biodegradable material in food packaging as well as in edible coatings for the preservation of food products.

Evaluating the antimicrobial effects of turmeric, ginger and clove extracts on some food pathogen

The aim of this study was to investigate the antibacterial effects of hydroalcoholic extracts of turmeric, ginger and clove on food pathogens including Salmonella Typhimurium, Shigella Dysenteriae and E. coli. To determine the antimicrobial effects, certain volumes of hydroalcoholic extracts of turmeric, ginger and clove were added to the blank disks, and after culturing the bacteria in Müller-Hinton Agar culture medium, the disks were placed on the culture medium and after the time required for the growth of the microorganism, the cultures were examined for the diameter of the growth inhibition zone. Among the aqueous extracts, the highest antibacterial effect was related to the aqueous extract of turmeric on Escherichia coli pathogen with an average diameter of the growth inhibition zone of 17 mm and the lowest antibacterial effect was related to the aqueous extract of turmeric versus Salmonella with an average diameter of the growth inhibition zone of 9.5 mm. Among ethanolic extracts, the highest antibacterial effect was related to turmeric and ginger against Escherichia coli and Shigella (average diameter of growth inhibition zone 15.1 mm) and the lowest effect was related to ethanolic extract of turmeric versus Salmonella (mean diameter of growth inhibition zone of 10 mm. Among methanolic extracts, the highest antibacterial effect was related to turmeric methanolic extract versus Shigella (mean diameter of growth inhibition zone of 16.8 mm) and the lowest effect was related to methanolic extract of clove versus Escherichia coli (mean diameter of growth inhibition zone of 10.5 mm). Among the studied pathogens, Salmonella showed the highest sensitivity to the hydroalcoholic extracts of the medicinal plants used, and the highest resistance was obtained for Shigella. Considering that the hydroalcoholic extracts of turmeric, ginger and clove have antimicrobial properties, they can be used as food preservatives against Salmonella, Escherichia and Shigella.

In vitro antibacterial activity of essential oils from Carum copticum and Ziziphora clinopodioides plants against the phytopathogen Pseudomonas syringae pv. syringae

The present study aimed to determine the in vitro antibacterial activity and the chemical composition of essential oils (EOs) from two medicinal plants (seeds of Carum copticum L. and leaves of Ziziphora clinopodioides Lam) against the bacterial plant pathogen Pseudomonas syringae pv. syringae. The sensitivity of P. syringae to the two types of EOs was investigated through three methods including disc diffusion, well diffusion, and vapor phase tests. Gas chromatography (GC) and gas chromatography attached to a mass spectrometer (GC-MS) were used to identify and quantify the essential oil compounds. The greatest growth inhibition zones for disc diffusion, well diffusion, and vapor tests were observed for the highest essential oil volume (50 µL) of Z. clinopodioides as 0.925 cm, 1.75 cm, and 1.45 cm, respectively. Concerning the EOs from C. copticum seeds, the diameters of growth inhibition zones were 0.775 cm, 1 cm, and 0 cm, respectively. Based on the obtained results, the highest antibacterial activity, with a growth inhibition zone of 1.75 cm, belonged to 50 µL EOs of Z. clinopodioides on Luria-Bertani (LB) agar medium. The minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) for the EOs of Z. clinopodioides were 8 µL mL−1 and 1 µL mL−1 in LB agar medium. The MBC and MIC values for EOs of C. copticum were 16 µL mL−1 and 1 µL mL−1, in LB agar medium, respectively. According to the chromatography results, 16 different compounds were identified in the EOs of C. copticum, of which thymol (54.6%) was the major constituent. Moreover, 27 different compounds were identified in the Z. clinopodioides EOs, of which pulegone (23%) and 1,8 cineole (20.3%) were the main essential oil constituents. The results demonstrated that the EOs of Z. clinopodioides plants had higher chemical diversity and displayed stronger antibacterial activities against P. syringe pv. syringae, compared to those of C. copticum.

Comparative evaluation of antibacterial efficacy of nonsteroidal anti-inflammatory medications and proton-pump inhibitor against Enterococcus faecalis: An in vitro study.

The present in vitro experimental study was undertaken to evaluate and compare the antimicrobial activity of triple antibiotic paste (TAP), diclofenac, and proton-pump inhibitor (PPI) against the microorganism Enterococcus faecalis. Three medicaments were selected for the study, TAP, diclofenac, and PPI. The experimental groups for the test were as follows: Part 1 - Group 1: TAP, Group 2: diclofenac, and Group 3: PPI; Part 2 - Group 1: TAP + PPI and Group 2: diclofenac + PPI. An agar well diffusion test was used to determine the efficacy of the experimental medicaments against E. faecalis (ATCC 29212). The diameter of inhibition zones was measured in millimeters using an inhibition zone measuring scale and the results were recorded. The statistical analysis was done using an analysis of variance and an unpaired t-test. P value was set at < 0.05. There was a significant difference in the diameter of growth inhibition zones, with the greatest diameter noted for TAP + PPI followed by diclofenac sodium (DS) + PPI, TAP, DS, and PPI. The antimicrobial effectiveness of TAP + PPI was found to be superior to all other medicaments (DS + PPI, TAP, DS, and PPI).