Antibacterial and antibiofilm activity of Mexican Mejhoul date (Phoenix dactylifera L.) seed extract against pathogenic bacteria

Antibacterial, anti-biofilm activity and mechanism of action of pancreatin doped zinc oxide nanoparticles against methicillin resistant Staphylococcus aureus

Antibiofilm and synergistic antibacterial effect of Garlic (Allium sativum) against Methicillin resistant Staphylococcus aureus (MRSA)

Background: The date fruit is a remarkable source of nutraceuticals and bioactive compounds. Different types of phenolic compounds with high antioxidant capacity are found in date seed extract. Additionally, these compounds can be potential antibacterial agents to combat antibiotic resistance strains. Therefore, the main idea of the current study was to quantify five key phenolic acids in the ethanolic extract of Zahidi and Khastawi dates seed and to examine their antibacterial activity against methicillin-resistant Staphylococcus aureus (MRSA). Methods: The concentration of gallic acid, ferulic acid, p-coumaric acid, sinapic acid and cinnamic acid in the seed extracts were determined by high performance liquid chromatography (HPLC). Then, antibacterial activity of date seed extracts was analyzed using well diffusion method. Furthermore, a scanning electron microscopy (SEM) analysis was performed to confirm the antibacterial effects of the seed extracts.Results: Phenolic acids were found to be in the range of 10.59 to 33.65 µg mg-1 in Zahidi and 13.69 to 41.56 µg mg-1 in Khastawi date seed extract. Gallic acid was the dominant phenolic acid, while cinnamic acid was seen in the lowest concentrations compared with the other phenolic acids in both cultivars. Antibacterial activity study showed that the growth inhibition effect of Khastawi date (14±0.21 mm) was higher than that of Zahidi date (8±0.13 mm) against MRSA. As well, the maximum DPPH scavenging percentage was 79% and 62% for the Khastawi and Zahidi date seed extracts, respectively. Also, SEM analysis suggested that treatment of MRSA with date seed extract resulted in a significant disruption of bacterial structure. Conclusion: It can be concluded that date seed extract can be considered as a potential source of antibacterial compounds for the drug discovery purposes.

The bacterial resistance to antibiotics has compromised the therapies used for bacterial infections. Nowadays, many strategies are being carried out to address this problem. Among them, the use of natural compounds like cinnamic and p-coumaric acids stands out. Nevertheless, their utilization is limited because of their unfavorable physicochemical properties. Due to the lack of new therapeutic alternatives for bacterial infections, novel strategies have emerged, such as the use of ionic liquids; given that they can show a broad spectrum of antibacterial activity, this is why we herein report the antibacterial and antibiofilm activity of a series of N-alkylimidazolium salts functionalized with p-coumaric and cinnamic acids. The results from this study showed better antibacterial activity against Gram-positive bacteria, with a predominance of the salts derived from coumaric acid and a correlation with the chain length. Additionally, a lower efficacy was observed in the inhibition of biofilm formation, highlighting the antibiofilm activity against Staphylococcus aureus, which decreased the production of the biofilm by 52% over the control. In conclusion, we suggest that the salts derived from p-coumaric acid are good alternatives as antibacterial compounds. Meanwhile, the salt derived from cinnamic acid could be a good alternative as an antibiofilm compound.

Chemical composition, antibiofilm activity, and antibacterial potential in vitro and in a zebrafish model of Myrciaria pilosa Sobral & Couto essential oil.

Abstract: Honey is a natural product that has been widely used for its therapeutic effects. Honey is effective against pathogenic bacteria in inhibiting planktonic antibiotic sensitive strains and antimicrobial resistant organisms. To date, there is no comparative study of the antibacterial activity of Citrus honey (CH) and Jabali honey (JH) with that of Manuka honey (MH). Therefore, the purpose of this study was to conduct such study and to compare the antibacterial activity of CH and JH with that of MH against Pseudomonas aeruginosa. The antibacterial, antibiofilm and antivirulence activities of CH, JH and MH against P. aeruginosa were investigated by agar well diffusion, Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC), time-kill curve, disruption of microcolony, microtiter plate and reverse transcription-quantitative Quantitative Real-Time Polymerase Chain Reaction (RT-qPCR). Agar inhibition assay showed that CH, JH and MH at 20% has antibacterial activity against P. aeruginosa with an inhibition zone of 14.1±0.1 mm, 12.2±0.2 mm and 10.9±0.1 mm respectively. The results showed that the MICs value of CH and JH was 25% compared to MH (12.5%) and the MBCs value of CH and JH was 50% compared to MH (25%) against P. aeruginosa. In addition, the MIC50 and MIC90 for CH and JH were 25% and 50% respectively compared to MH (MIC50; 12.5% and MIC90; 25%) against P. aeruginosa. All tested honeys were found to disrupt the microcolony formation in P. aeruginosa. In time-kill curve, treatment of P. aeruginosa with 2×MIC (Minimum inhibitory concentration) of MH, CH and JH for 12-hours resulted in reduction in colony-forming unit (CFU/ml). The lowest concentration of 20% of MH, CH and JH was found to inhibit and eradicate biofilm formation. RT-qPCR analysis revealed that the expression of all genes (oprB, oprC, fleN, fleQ, fleR, lasR and lasI) in P. aeruginosa were downregulated after exposure to all tested honeys. Among the all-tested honeys, MH showed the highest total antibacterial, antibiofilm and antivirulence activities. This study indicates that CH and JH has antibacterial and antibiofilm activities compared with MH due to a decrease in expression of essential genes associated with P. aeruginosa.

Background Bacterial infections caused by the genus Staphylococcus represent a grave threat to both humans and animals, and they are a major concern to health authorities. Over the past few decades, methicillin-resistant Staphylococcus aureus (MRSA) has been recognized as the principal nosocomial pathogen worldwide. Objective To investigate the antibacterial and antibiofilm activity of Lactobacillus acidophilus against locally isolated MRSA at different concentrations. Materials and methods MRSA isolates were tested against some antibiotics for testing antibiotic sensitivity. The antibacterial activity of L. acidophilus based on the minimal inhibitory concentration (MIC) of L. acidophilus that inhibits the visible growth of MRSA isolates was assessed using the microdilution method. Estimation of MIC of L. acidophilus was done. Biofilm quantification assay was then used for the determination of the antibiofilm activity of L. acidophilus. The MIC concentration was assessed by a microtiter reader. Results and conclusion The antibacterial activity was tested by agar diffusion method and broth microdilution method. The microdilution method was used to determine the MIC of L. acidophilus, whereas the antibiofilm activity was determined by using 96-well polystyrene microtiter plates. The results revealed that L. acidophilus has antibacterial activity in a concentration-dependent manner. The average diameter zone of inhibition observed against MRSA isolates ranged from 11±0.5 to 18±0.5 mm Moreover, at subinhibitory concentration, this extract developed an isolate-specific antibiofilm effect and presented highly significant (P<0.05) variability in biofilm formation before and after addition of L. acidophilus. AA3 and AA12 isolates gave the lowest and highest antibiofilm activity, respectively. In conclusion, the supernatant of L. acidophilus is a promising alternative medication that can be used to treat the infection caused by MRSA.

Antimicrobial resistance is an emerging public health threat. Foodborne illnesses are typically caused by bacteria, such as Escherichia coli, Pseudomonas aeruginosa, Bacillus cereus, and Staphylococcus aureus, which are frequently resistant to common antimicrobial agents. Rice is a staple grain in most parts of the world. Our previous work showed that Phatthalung Sangyod rice seed protein hydrolysates (SYPs), especially SYP4, exhibit antifungal activity against several fungal species that are pathogenic for both humans and animals and are non-cytotoxic to animal red blood cells. In this study, we aimed to determine the effects of the bioactive peptides in SYPs against several pathogenic bacteria in humans and animals. After isolating SYP1, it was treated as follows: heated (SYP2), and hydrolyzed using pepsin (SYP3), and proteinase K (SYP4). Then, we used 500 μg of protein to evaluate the antibacterial effects on four pathogenic bacteria, including E. coli, P. aeruginosa, B. cereus, and S. aureus, using agar well diffusion. Using a broth microdilution assay, we determined the minimum inhibitory and bactericidal concentration (MIC and MBC, respectively) values of active SYPs. Using the agar well diffusion and microtube incubation methods, we also assessed the inhibitory effects of SYPs on the bacterial quorum sensing (QS) activity of Chromobacterium violaceum. Sangyod rice seed protein hydrolysates were evaluated for their ability to inhibit the biofilm formation of bacterial cells by a crytal violet assay. Furthermore, using the dropping method, we tested the inhibitory effects of SYPs on the bacterial pigments pyocyanin in P. aeruginosa and staphyloxanthin in S. aureus. Our results showed that the crude protein lysate (SYP1) did not exhibit antibacterial activity against any of the test bacteria. Intriguingly, after boiling (SYP2) and enzymatic hydrolysis (SYP3 and SYP4), the protein hydrolysates were transformed into bioactive peptides and displayed antibacterial properties against all of the test bacteria at a concentration of 500 μg as determined by agar well diffusion. SYP4 demonstrated the highest antibacterial activity as it completely inhibited all test strains, with inhibition zones ranging from 16.88 ± 0.25 to 21.25 ± 0.5 mm, and also yielded the highest MIC/MBC values against P. aeruginosa, B. cereus, and E. coli, at 256 and >256 μg/mL, respectively. We observed that at least 256 μg/mL of SYP4 is required to exhibit optimal antibacterial activity. At 16-128 μg/mL, it exhibited antibiofilm activity against S. aureus. Furthermore, at 256 μg/mL, SYP4 inhibited pyocyanin in P. aeruginosa and staphyloxanthin in S. aureus. Although SYP2 and SYP3 displayed weak antibacterial activity and their MIC values could not be obtained for all bacteria, they showed strong QS inhibition in C. violaceum at 256 μg protein. Moreover, SYP2 and SYP3, at a minimum concentration of 32 μg/mL, significantly reduced violacein production. SYP3 also showed biofilm reduction activity on S. aureus at least 16-512 μg/mL. Sangyod Phatthalung protein hydrolysates exerted excellent inhibitory effects against the growth of bacteria and their virulence factors, such as QS, biofilm formation, and/or pigment production. These factors include zoonotic and foodborne pathogens. Therefore, daily consumption of Sangyod Phatthalung rice might reduce the risk of bacterial pathogenesis and foodborne diseases. In conclusion, functional foods or alternate methods of treating bacterial illnesses may be developed in humans and animals.

Since penicillin was discovered, antibiotics have been critical in the fight against infections. However, antibiotic misuse has led to drug resistance, which now constitutes a serious health problem. In this context, antimicrobial peptides (AMPs) constitute a natural group of short proteins, varying in structure and length, that act against certain types of bacterial pathogens. The antimicrobial peptide 1018-K6 (VRLIVKVRIWRR- NH2) has significant bactericidal and antibiofilm activity against Listeria monocytogenes isolates, and against different strains and serotypes of Salmonella. Here, the mechanism of action of 1018-K6 was explored further to understand the peptide–membrane interactions relevant to its activity, and to define their determinants. We combined studies with model synthetic membranes (liposomes) and model biological membranes, assessing the absorption maximum and the quenching of 1018-K6 fluorescence in aqueous and lipid environments, the self-quenching of carboxyfluorescein, as well as performing lipid sedimentation assays. The data obtained reflect the differential interactions of the 1018-K6 peptide with eukaryotic and prokaryotic membranes, and the specific interactions and mechanisms of action in the three prokaryotic species studied: Salmonella Typhimurium2GN, Escherichia coli3GN, and Staphylococcus aureus3GP. The AMP 1018-K6 is a candidate to prevent (food preservation) or treat (antibiotic use) infections caused by certain pathogenic bacteria, especially some that are resistant to current antibiotics.

Antimicrobial activity of several essential oils on pathogenic and beneficial bacteria

Background: The number of caesarean section (CS) operations in the world has increased sharply within the last 20 years. Increase of the need for CS operations also increases the problem related to surgical process. Infection happens about 2% to 16% after CS operation. The incidence of post CS is associated with some factors such as supplementation of prophylaxis antibiotics, duration of childbirth, width of membrane wound, duration of surgical nursing monitoring and number of CS. CS infection associated with antibiotic use occurs before or after CS operation. The incidence increases 3 times in patients that do not use antibiotics before CS operation. Use of prophylaxis antibiotics in CS operation significantly minimizes the incidence of infection.Objective: To identify antibiotic use according to standard operational procedure to the incidence of infection in CS mothers.Method: The study was analytical with cross sectional design, undertaken at Abepura Local Hospital. Population were all mothers who gave birth through CS at the hospital. Samples were taken using systematic random sampling technique as many as 44 samples. Data were obtained through questionnaire, interview and document studies and analyzed using chi square and logistic regression test, risk prevalence at confidence interval (CI) 95% and significance p<0.05.Result: The majority of subject (56.82%) had no infection; 59.09% used antibiotics according to the procedure; 52.27% had good nutrition status; 54.55% had emergency operation; 50% had anemia. Average length of CS operation was 2.26 +1.38 hours. There was significant association between antibiotic use, nutrition status, Hb level, and types of operation and the incidence of CS infection (p<0.05). The result of multivariate analysis showed there was significant association between antibiotic use, nutrition status, types of operation and the incidence of infection. Use of antibiotic brought dominant risk for the incidence of CS infection (PR=2.36; 95% CI=1.45-3.38) whereby antibiotic use, nutrition status and types of operation could predict the incidence of CS infection as much as 10.7%.Conclusion: The majority of subject had no infection and used antibiotic according to the procedure. The probability for the incidence of CS infection was greater in antibiotic use irrelevant with the procedure. Factor most dominantly affecting the incidence of CS infection was antibiotic use irrelevant with the procedure. Keywords: antibiotic use, caesarean section, incidence of infection

The current study was aimed to investigate the antibacterial and antibiofilm activity of ethanolic extract of Hibiscus sabdariffa L. calyx against locally isolated methicillin-resistant Staphylococcus aureus (MRSA) at different concentrations were started from 0.078 to 40 mg/ml. The extract was prepared by soaked calyces powder of Hibiscus sabdariffa L. with 80% ethanol in the Soxhlet extraction unit, and then it was aseptically filtered. The antibacterial activity was tested by agar diffusion method and broth microdilution method, this method was used to determine the minimum inhibitory concentration of extract, while the antibiofilm activity was determined by using 96-well polystyrene microtiter plates. The results revealed that the ethanolic extract has antibacterial activity in a concentration-dependent manner, the average diameter zone of inhibition observed against MRSA isolates ranged from 14±0.5 mm to 20±0.5 mm Moreover, at sub-inhibitory concentration, this extract developed an isolate-specific antibiofilm effect and presented highly significant (P< 0.05) variability in biofilm formation before and after addition of ethanolic extract, Mr1, and Mr7 isolates were gave the lowest and highest antibiofilm activity, respectively. In conclusion, the ethanolic extract of H. sabdariffa L. calyx is a promising alternative medication that can be used to treat the infection caused by MRS.

The by-products resulted from the processing of raw vegetables contain sometimes appreciable amounts of bioactive compounds can be extracted, purified, concentrated and reused as antipathogenic agents. By altering the pathogenicity of microorganisms, the virulence of the pathogen is attenuated. The objective of this work is to analyze the antibacterial, anti-quorum sensing, anti-biofilm and antioxidant activity of Beta vulgaris (beet) and Allium porrum (leek) leaves as possible antipathogenic agents. The ethanolic extracts of dehydrated beet leaves (EEDBL) showed greater antioxidant activity and a higher concentration of polyphenols than those of ethanolic extract of dehydrated leek leaves (EEDLL). The EEDLL showed major antibacterial activity with a minimal inhibitory concentration (MIC) of 358.33 mg mL−1 and anti-quorum sensing activity at 53.75 mg mL−1 than the EEDBL. Moreover, the EEDLL showed anti-biofilm activity at 268.75 mg mL−1. The use of bioactives extracted from unused portions of different vegetables as antipathogenic substances it is proposed as an alternative to the use of traditional antibacterials.

Catheter-associated urinary tract infections (CAUTIs) cause serious complications among hospitalized patients due to biofilm-forming microorganisms which make treatment ineffective by forming antibiotic-resistant strains. As most CAUTI-causing bacterial pathogens have already developed multidrug resistance, there is an urgent need for alternative antibacterial agents to prevent biofilms on catheter surfaces. As a trial to find out such a potential agent of natural origin, the bark of Tamarix ericoides Rottl., a little-known plant from the Tamaricaceae family, was examined for its antibacterial and antibiofilm activities against one of the major, virulent, CAUTI-causing bacterial pathogens: Enterococcus faecalis. The methanolic T. ericoides bark extract was analyzed for its antibacterial activity using the well diffusion method and microdilution method. Killing kinetics were calculated using time-kill assay, and the ability of biofilm formation and its eradication upon treatment with the T. ericoides bark extract was studied by crystal violet assay. GC-MS analysis was performed to understand the phytochemical presence in the extract. A in vitro bladder model study was performed using extract-coated catheters against E. faecalis, and the effect was visualized using CLSM. The changes in the cell morphology of the bacterium after treatment with the T. ericoides bark extract were observed using SEM. The biocompatibility of the extract towards L929 cells was studied by MTT assay. The anti-E. faecalis activity of the extract-coated catheter tube was quantified by viable cell count method, which exposed 20% of growth after five days of contact with E. faecalis. The anti-adhesive property of the T. ericoides bark extract was studied using CLSM. The extract showed potential antibacterial activity, and the lowest inhibitory concentration needed to inhibit the growth of E. faecalis was found to be 2 mg/mL. The GC-MS analysis of the methanolic fractions of the T. ericoides bark extract revealed the presence of major phytochemicals, such as diethyl phthalate, pentadecanoic acid, methyl 6,11-octadecadienoate, cyclopropaneoctanoic acid, 2-[(2-pentylcyclopropyl) methyl]-, methyl ester, erythro-7,8-bromochlorodisparlure, etc., that could be responsible for the antibacterial activity against E. faecalis. The killing kinetics of the extract against E. faecalis was calculated and the extract showed promising antibiofilm activity on polystyrene surfaces. The T. ericoides bark extract effectively reduced the E. faecalis mature biofilms by 75%, 82%, and 83% after treatment with 1X MIC (2 mg/mL), 2X MIC (4 mg/mL), and 3X MIC (6 mg/mL) concentrations, respectively, which was further confirmed by SEM analysis. The anti-adhesive property of the T. ericoides bark extract studied using CLSM revealed a reduction in the biofilm thickness, and the FDA and PI combination revealed the death of 80% of the cells on the extract-coated catheter tube. In addition, SEM analysis showed extensive damage to the E. faecalis cells after the T. ericoides bark extract treatment, and it was not cytotoxic. Hence, after further studies, T. ericoides bark extract with potential antibacterial, antibiofilm, and anti-adhesive activities can be developed as an alternative agent for treating CAUTIs.

Prosthodontics- 2017- Infected Mandibular Fractures: Risk Factors and Management- Ehab Abdelfadil- Mansoura University