Coli ATCC Research Articles

Antimicrobial effects of Rosmarinus Officinalis; in-vitro study

Introduction: The plant Rosmarinus officinalis (RO) is a member of the Lamiaceae family and is more commonly known as rosemary. This study's primary objective is to compare the antimicrobial effect of RO extract at different concentrations on various microorganisms.
 Material and Methods: Strains of S. aureus ATCC 29213, K. pneumoniae ATCC 13883, and E. coli ATCC 25922 obtained from the national reference center were inoculated into liquid Müller Hinton broth (Oxoid, UK) and incubated at 37 oC’ for 24 hours. To assess the antimicrobial efficacy of the RO extract, dilutions of 0.0625%, 0.125%, 0.25%, 0.5%, 1%, 2%, 3%, and 4% were prepared.
 Results: The MIC value for RO extract was 2% for S. aureus ATCC 29213 and K. pneumoniae ATCC 13883 and 3% for E. coli ATCC 25283. A statistically significant difference was found between the three groups, including 0.0625% and 2% of RO, in terms of the growth rates of microorganisms (p

Isolation of Escherichia coli bacteriophages from Domestic Wastewater in Tangerang Selatan

In recent years, there has been a continuous increase in the prevalence of antibiotic resistance among bacteria responsible for infectious diseases. Several studies have shown that the occurrence of the COVID-19 pandemic is a major factor contributing to this rapid increase. To overcome this challenge, one promising approach is the use of bacteriophages as a treatment option. Therefore, this study aims to isolate E. coli lytic bacteriophages as an alternative antibiotic for treating secondary bacterial infections of COVID-19. Isolation of bacteriophages was carried out using the plaque assay method with double layer agar technique. The isolate obtained was purified and tested for effectiveness in lysing E. coli ATCC 25922 bacterial cells. The results showed that E. coli had resistance to antibiotics, such as Amoxicillin, Clindamycin, Ciprofloxacin, Azithromycin, and Trimethoprim/sulfamethoxazole. BEB1 isolate obtained from domestic waste had activity in inhibiting the growth of the test bacteria with an effectiveness of 72% at the 25th hour. Based on these findings, it had the potential to be developed as an alternative antibiotic agent to overcome infectious diseases caused by E. coli ATCC 25922.

Single-step, electrophoretically deposited hydroxyapatite/poly(vinyl alcohol)/chitosan/gentamicin coating for biomedical applications

Biocomposite hydroxyapatite/poly(vinyl alcohol)/chitosan/gentamicin coatings were fabricated on titanium by electrophoretic deposition process (EPD) from an aqueous suspension using the constant voltage method. Characterization of the deposited coatings was performed by scanning electron microscopy with field emission (FE–SEM), Fourier transform infrared spectroscopy (FT–IR) and X-ray diffraction (XRD) after immersion in simulated body fluid (SBF) at 37 °C. The concentration of the released gentamicin was determined using a high-performance liquid chromatography (HPLC) coupled with a mass spectrometer (MS). The release profile confirmed an initial “burst-release effect” with ~ 30% of gentamicin released in the first 48 h, which could be of assistance in the prevention of biofilm formation. Antibacterial activity was proven by the agar diffusion method on Staphylococcus aureus TL and Escherichia coli ATCC 25922 bacterial strains. Cytotoxicity was tested by the dye exclusion test (DET) on MRC-5 and L929 fibroblast cell lines, with both coatings expressing nontoxicity. The results showed the high applicability potential of a poly(vinyl alcohol)-based biocomposite coating for medical purposes.

Synthesis, Characterization, and Antibacterial Efficacy of Borosilicate Compound against Escherichia coli

In this study, a glassy borosilicate compound was synthesized using recycled glass and natural clays. Even though glass recycling is the generally accepted standard practice for managing glass waste, fine fractions of container soda-lime glass or cullet of other compositions are still disposed of in landfills. Thus, advanced upcycled products that offer greater economic motivation for implementation in industry may be the key to success, but these are frequently linked to alternative methods of product synthesis. Here, a simple and facile route of borosilicate compound production has been synthesized and characterized. The physicochemical characterization of the compounds was carried out to determine their properties and the antibacterial efficacy of the synthesized compound against Escherichia coli (E. coli) was investigated. The structural and spectroscopic characteristics were identified as a compound that conformed to quartz, cristobalite, and silicon hexaboride (SiB6). For the antibacterial activity, two test types were typically performed; in the first one, the dilutions of the grind were combined with chloramphenicol at a concentration of 20 µg/mL to perform a synergistic action against the bacteria and in the second one, only the amorphous borosilicate compound was tested against E. coli ATCC 25922 strains. The treatments applied considered the dilutions from 8 to 40 µg/mL. The minimum inhibitory concentration (MIC) sensitivity tests began with incubation at 37 °C in the tubes and subsequent seeding in Petri dishes for colony-forming unit (CFU) counting. The results obtained indicated that the samples possessed a productive antibacterial effect, which support their use in various biomedical applications.

Preparation and Antimicrobial Activity of a Film-Forming Polyhexamethylene Biguanide Teat Disinfectant.

Bovine mastitis caused by infectious pathogens can lead to a decline in production performance and an increase in elimination rate, resulting in huge losses to the dairy industry. This study aims to prepare a novel dairy cow teat disinfectant with polyhexamethylene biguanide (PHMB) as the main bactericidal component and to evaluate its bactericidal activity in vitro and its disinfection effect in dairy cow teats. PHMB disinfectant with a concentration of 3 g/L was prepared with PVA-1788, propylene glycol and glycerol as excipients. When the dilution ratio is 1:4800 and the action time is 5 min, the PHMB teat disinfectant can reduce the four types of bacteria (S. agalactiae ATCC 12386, S. dysgalactiae ATCC 35666, S. aureus ATCC 6538, and E. coli ATCC 8099) by 99.99%. PHMB teat disinfectant applied on the skin of rabbits with four bacteria types achieved an average log10 reduction greater than 4. After 30 s of PHMB teat disinfectant dipping, the bacteria of cow teats were counted prior to disinfection. The mean log10 reduction in bacteria on the skin surface of 12 cows ranged from 0.99 to 3.52 after applying the PHMB teat disinfectant for 10 min. After 12 h, the PHMB teat disinfectant achieved an average log10 reduction in bacteria from 0.27 to 0.68 (compared with that prior to disinfection). These results suggested that PHMB teat disinfection has the potential to prevent and treat mastitis-causing bacteria in dairy herds.

Synthesis of Colloidal Silver Nanoparticles Using Alginate as Reducing and Stabilizing Agents and its Application as Antibacterial Material

Synthesis of colloidal silver nanoparticles has been successfully conducted through the chemical reduction technique. The synthesis used AgNO3, NaOH, and alginate as the precursor, accelerator reagent, and reducing agent and stabilizer, respectively. The effects of heating temperature, reaction time, accelerator concentration, and precursor concentration were investigated according to the localized surface plasmon resonance (LSPR) phenomenon using a UV-Vis spectrophotometer. The nanoparticle size distribution was observed via a Particle Size Analyzer (PSA). The stability of silver nanoparticles was studied for 8 weeks based on the LSPR phenomenon. Then, their antibacterial performance toward S. Aureus ATCC 25923 and E. Coli ATCC 25922 was examined. The results showed the absorbance intensities representing the number of silver nanoparticles formed were influenced by temperature, reaction time, NaOH concentration, and AgNO3 concentration. At 50°C heating, the optimum synthesis of silver nanoparticles was achieved at 50 min with a NaOH concentration of 0.013M. The higher AgNO3 concentration resulted in a greater concentration of silver nanoparticles produced. From the PSA characterization, the average particle sizes for the samples were 1.82 nm and 1.30 nm for AgNO3 concentrations (% w/w; AgNO3/Alginate) of 1.6% and 2.4%, respectively. Based on the LSPR phenomenon, colloidal silver nanoparticles were stable in storage for 8 weeks at room temperature. The increase in the concentration of silver nanoparticles within colloidal could enhance antibacterial performance against S. Aureus and E. Coli. Accordingly, silver nanoparticles synthesized with alginate as a stabilizer have the potential as an antibacterial compound for medical applications.

Antimicrobial effects of hydrogel implants incorporating gold nanoparticles and albucide and developed for reconstructive surgery in the orbit and periorbital area

Background: It is important to develop orbital hydrogel implants capable of depositing drugs (particularly, antimicrobial and anticancer drugs). Purpose: To assess antimicrobial effects of hybrid hydrogel implants containing gold nanoparticles and albucide and developed for reconstructive surgery in the orbit and periorbital area. Material and Methods: A 30% aqueous solution of albucide was used in the study. Antimicrobial activity of synthesized hydrogels was determined using Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29213, Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853 strains. Results: All the synthesized samples of orbital hydrogel implants were sterile. The synthesized hydrogels and hydrogel nanocomposites with incorporated Au nanoparticles demonstrated bacteriostatic effects against E. Coli ATCC 25922, E. Faecalis ATCC 29213, and S. Aureus ATCC 25923 strains, and bactericidal effects against P. Aeruginosa ATCC 27853 strain. This study also demonstrated marked bactericidal effects of hybrid hydrogel implants incorporating both Au nanoparticles and albucide. Conclusion: Orbital hydrogel implants were found to be sterile after being sealed into polypropylene bags and steam sterilized at 121 °C for 20 minutes. Our findings of bacteriostatic and bactericidal effects of the synthesized hydrogels and hydrogel nanocomposites containing Au nanoparticles and albucide against bacterial strains of interest will allow for the absence of, or low probability of bacterial contamination in applications of these hydrogels in implants.

Retinal apoptosis and the effect of tyrosine kinase inhibition in experimental diabetes

Background: It is important to develop orbital hydrogel implants capable of depositing drugs (particularly, antimicrobial and anticancer drugs). Purpose: To assess antimicrobial effects of hybrid hydrogel implants containing gold nanoparticles and albucide and developed for reconstructive surgery in the orbit and periorbital area. Material and Methods: A 30% aqueous solution of albucide was used in the study. Antimicrobial activity of synthesized hydrogels was determined using Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29213, Staphylococcus aureus ATCC 25923 and Pseudomonasa eruginosa ATCC 27853 strains. Results: All the synthesized samples of orbital hydrogel implants were sterile. The synthesized hydrogels and hydrogel nanocomposites with incorporated Au nanoparticles demonstrated bacteriostatic effects against E. Coli ATCC 25922, E. Faecalis ATCC 29213, and S. Aureus ATCC 25923 strains, and bactericidal effects against P. Aeruginosa ATCC 27853 strain. This study also demonstrated marked bactericidal effects of hybrid hydrogel implants incorporating both Au nanoparticles and albucide. Conclusion: Orbital hydrogel implants were found to be sterile after being sealed into polypropylene bags and steam sterilized at 121 °C for 20 minutes. Our findings of bacteriostatic and bactericidal effects of the synthesized hydrogels and hydrogel nanocomposites containing Au nanoparticles and albucide against bacterial strains of interest will allow for the absence of, or low probability of bacterial contamination in applications of these hydrogels in implants.

Exploring the antibacterial mechanisms of chemically characterized essential oils from leaves and buds of Syzygium aromaticum (L.) Merr. et Perry against Staphylococcus aureus and Pseudomonas aeruginosa

Syzygium aromaticum (L.) Merr. et Perry is a medicinal plant extensively used in international pharmacopeia to treat different ailments, including infectious diseases. In this study, we designed to determine the chemical constituents of S. aromaticum essential oils extracted from leaves (CEOL) and floral buds (CEOB) and their antibacterial mechanism of action against S. aureus and P. aeruginosa. The volatile components from CEOL and CEOB were detected using gas chromatography coupled to a mass spectrometer (GC/MS). The results indicated that eugenol was the major component for both CEOL (65.75%) and CEOB (74.03%). The antibacterial findings demonstrated the potent antibacterial activity of CEOL and CEOB. These oils exhibited significant zones of inhibition against all tested bacteria, including S. aureus ATCC 29213, K. aerogenes ATCC 13048, P. aeruginosa ATCC 27853, and E. coli ATCC 25922, surpassing the effects of antibiotics. Additionally, they displayed low minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs), indicating their bactericidal nature (MBC/MIC < 4.0). Time-kill kinetics revealed that CEOB was more effective than CEOL at sub-MIC doses, eradicating S. aureus within 12 h and P. aeruginosa within 12–24 h. The cell membrane permeability test demonstrated that CEOL and CEOB treatment affected the relative conductivity of S. aureus and P. aeruginosa at both MIC and sub-MIC concentrations, indicating disruption of the bacterial membrane and influencing their growth and viability. Furthermore, the cell membrane integrity test showed that the addition of CEOL and CEOB to S. aureus and P. aeruginosa cultures led to significant protein release from the bacterial cells. The results of the anti-biofilm activity test confirmed the efficacy of S. aromaticum EOs, particularly CEOB, as potent anti-biofilm agents, suggesting its potential effect on inhibiting quorum sensing. Scanning electron microscope (SEM) microscopy further revealed significant alterations in bacterial cells treated with CEOB essential oil, including damage to the cell wall and distorted cell morphology, highlighting its impact on bacterial cell structure. Presented information suggests the use of clove EOs as natural alternatives for sustainable application in food and pharmaceutical industries.

Synthesis, characterization and DFT studies of novel Schiff base derivatives of curcumin as potential antibacterial agents

Curcumin has immense medicinal value in traditional medicine and is known to have anti-tumor, anti-microbial and anti-oxidant properties. Molecular structure of curcumin has a very interesting functionality profile that permits novel modifications. This work specifically focuses on the synthesis of a series of schiff base derivatives of curcumin (3a–3h) which were primarily characterized by FT-IR, 1HNMR , 13CNMR and HR-MS. In a bid to study the biocidal activity of these compounds, the studies were performed on S. aureus ATCC 25923 and E. Coli ATCC 25922. MIC for these compounds were found in the range of 250 µg/mL to 500 µg/ml. Anti-oxidant property was determined using the DPPH radical scavenging method. Further, radical scavenging activity was extended to nitric oxide and hydroxyl radicals. DFT calculations were carried out for theoretical understanding and energy analysis to support the experimental data. In silico studies were carried out using ADMET to predict in vivo interactions and toxicity.

Synthesis, Antioxidant and Antimicrobial Activity of Calix[4]Arene Acetanilide Derivative

The current work explores the antioxidant and antimicrobial activity of a newly synthesized calix[4] arene acetanilide derivative (3), which was synthesized through Mannich reaction by the treatment of calix[4] arene with acetanilide, formaldehyde and acetic acid in tetrahydrofuran, The antioxidant activity was determined by using DPPH method. Results show that the new synthesized compound 3 has good antioxidant activity. The antimicrobial activity of 3 was staunched against different types of microorganisms, i.e. gram-negative and gram-positive bacterial strains (Escherichia Coli ATCC 8739 and Staphylococcus Aureus ATCC 10231) along with a fungus (Aspergillus Niger ATCC 16405). A suitable agar medium (Mueller Hinton agar) was applied for the growth of microorganisms. Kirby-Bauer well agar diffusion method was used to check the antimicrobial activity. The bacterial strains zone has been observed in between 250–4000 µg/ml. It is noticed that compound 3 has very good effect against fungus A niger as compared to bacterial strains. Its minimum inhibitory concentration (MIC) against A. niger, S. aureus and E. coli is found to be 250, 500 and 1000 µg/mL, respectively. Consequently, the study has been compared with the reported calix[4] arene derivatives and it has been revealed that the compound 3 is a good antimicrobial agent. Hence, it could be inferred that compound 3 is considerably effective against selected microorganisms and may be used as a medicine in near future and beneficial for the human.

The effect of different aqueous solutions ratios of Ocimum basilicum utilized in AgNPs synthesis on the inhibition of bacterial growth

This study examined the effect of varying concentrations of Ocimum basilicum aqueous extract, which was done via the green synthesis of Silver nanoparticles (AgNPs), on the identification of the most effective concentration for bacteria inhibitory activity. Different concentrations of the aqueous Ocimum basilicum extract (0.25, 0.50, 0.75 and 1.00 mM) were used as reducing and stabilizing agent to synthesize AgNPs by means of the reduction method. The crystal structure and morphology of the NPs were characterized UV–Vis spectra, X-ray diffraction (XRD) and scanning electron microscopy (SEM). The antibacterial efficacy of AgNPs was studied against E. coli ATCC 35218 using well diffusion, MIC, MBC, and time-kill curve. The dark yellow color of the Ocimum basilicum aqueous solution indicates the successful synthesis process of the AgNPs. UV-spectra of the AgNPs display a gradual increase of absorption in sequence with concentration increase of aqueous Ocimum basilicum extract solution from 0.25 to 1.00 mM. This, in turn, led to a shift in the wavelength from 488 to 497 nm, along with a change in the nanoparticle size from 52 to 8 nm. The tests also showed a high activity of the particles against bacteria (E. coli), ranging between 15.6 and 62.5 µg/ml. Based on AgNPs, it was confirmed that an aqueous Ocimum basilicum extract can be used as an effective, reducing and stabilizing agent for the synthesis of different sizes of AgNPs based on the solvent concentration. The AgNPs also proved to be effective in inhibiting and killing bacteria.

In vitro Antibacterial Activities of Selected Medicinal Plants Used by Traditional Healers for Treating Urinary Tract Infection in Haramaya District, Eastern Ethiopia.

Despite the presence of antibacterial agents for urinary tract infection treatment, most of the uropathogenic bacteria reveal multi-drug resistance. Health and economic loss due to these represent a rising burden worldwide which necessitates serious action at regional, national and global levels. Thus, alternative approaches to overcome this problem by using bioactive compounds from traditional medicinal plants are required. This study was designed to evaluate the in-vitro antibacterial activity of Punica granatum fruit peels, Nigella sativa seeds, and Echinops kebericho used in the traditional treatment of urinary tract infections. An experimental study was employed to evaluate the in vitro antibacterial activity of methanol and ethanol crude extract of Punica granatum fruit peels, Nigella sativa seeds, and Echinops kebericho roots of six dilutions (25, 50, 100, 125, 250, and 500) mg/mL. Disc diffusion and macro broth dilution methods were used to determine antimicrobial activity test and minimum inhibitory concentration respectively against E. coli, P. aeruginosa, K. pneumoniae, P. mirabilis, and S. aureus bacterias. Antibacterial activities of ethanol and methanol crude extract of Punica granatum fruit peels against E. coli ATCC25922, P. aeruginosa ATCC27853, S. aureus ATCC25923, K. pneumoniae UK5099 and P. mirabilis UK5999 had highest inhibition zones among tested plants. All tested bacteria were highly sensitive to Punica granatum extract. The second most active plant extract in inhibiting the growth of tested bacteria was Nigella sativa while Echinops kebericho showed the smallest efficacy against tested bacteria. The inhibition zone diameter produced by the methanol extract of each screened plant had higher inhibition zones than ethanol extract. The crude extracts of Punica granatum fruit peels, Nigella sativa seeds, and Echinops kebericho roots have promising antibacterial activity against tested uropathogenic bacteria.

Antibacterial and Antimycotic Properties of Modified Carbon Sorbents

The aim of the work was to study the biological activity of modifiers and carbon sorbent samples modified by them in relation to some types of microorganisms.Material and methods. The carbon sorbent under study and the modified samples were obtained at the Center of New Chemical Technologies BIC. Glycolic acid, lactic acid, glycine, and glutamic acid were used as modifiers. Strains of Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae 418, Esherichia coli ATCC 25922, Candida albicans (clinical strain) were used as test cultures. The test sample was placed in the wells of a sterile plate, then a working suspension of the test culture was added in the amount of 2.0 ml until completely wet 1:1. The survival of microorganisms was determined by quantitative inoculation from each well of the «sample — microorganism» mixture on Petri dishes with simple nutrient agar using the sector crop method (Gold). The culture species were confirmed by studying their cultural, morphological, and biochemical properties.Results. The conducted studies have demonstrated high antibacterial and antimycotic activity of carbon sorbent samples modified with hydroxyl acids in relation to the most common opportunistic pathogens of pyoinflammatory diseases of bacterial and fungal nature in comparison with the initial sorbent sample. The carbon sorbent modified with lactic acid oligomer showed the highest antibacterial and antimycotic activity.Conclusion. High antibacterial and antimycotic activity of carbon sorbent samples modified with hydroxy acids and amino acids in relation to the most common opportunistic pathogens of pyoinflammatory diseases of bacterial and fungal nature was established in comparison with the initial sample of the sorbent. The carbon sorbent sample modified with amino acids has a pronounced antibacterial effect against all studied bacterial test strains, but exhibits weak antimycotic properties. The use of modified carbon sorbents is a promising direction for the application therapy of pyoinflammatory infections.

Two Predators, One Prey - the Interaction Between Bacteriophage, Bacterivorous Ciliates, and Escherichia coli.

Bacterivorous ciliates and lytic bacteriophages are two major predators in aquatic environments, competing for the same type of prey. This study investigated the possible interaction of these different microorganisms and their influence on the activity of each other. Therefore, two bacterivorous ciliates, Paramecium sp. RB1 and Tetrahymena sp. RB2, were used as representative ciliates; a T4-like Escherichia coli targeting lytic bacteriophage as a model virus; and E. coli ATCC 25922 as a susceptible bacterial host and prey. The growth of the two ciliates with E. coli ATCC 25922 as prey was affected by the presence of phage particles. The grazing activity of the two ciliates resulted in more than a 99% reduction of the phage titer and bacterial cell numbers. However, viable phage particles were recovered from individual washed cells of the two ciliates after membrane filtration. Therefore, ciliates such as Paramecium sp. RB1 and Tetrahymena sp. RB2 can remove bacteriophages present in natural and artificial waters by ingesting the viral particles and eliminating bacterial host cells required for viral replication. The ingestion of phage particles may marginally contribute to the nutrient supply of the ciliates. However, the interaction of phage particles with ciliate cells may contribute to the transmission of bacteriophages in aquatic environments.

Foliar Roughness and Water Content Impact on Escherichia coli Attachment in Baby Leafy Greens.

Understanding the relation between the susceptibility of different leafy greens to human pathogen contamination and leaf traits can contribute to increase the food safety of the fresh vegetable industry. The aim of this research was to evaluate the susceptibility to E. coli ATCC 35218 attachment in 30 accessions of baby leaves, and to identify leaf traits potentially involved in the contamination. The accessions were surface inoculated with a bacterial suspension containing 1 × 107 cells/mL and the attachment was measured 1.5 h after inoculation. Significant differences in attachment were detected between the accessions for p ≤ 0.05. The three most and the three least susceptible accessions were selected and characterized for leaf micro-morphological traits (stomata density and size, surface roughness) and water content. Scanning electron microscopy was used to analyse the stomatal parameters. Roughness was measured by an innovative portable 3D digital microscope. No significant correlation between the attachment of E. coli ATCC 35218 and stomatal parameters was detected, while the attachment was positively correlated with roughness and water content. The E. coli ATCC 35218 population in surface-inoculated leaves was also measured after a UV treatment, which was found to be less effective in reducing bacterial contamination in the rougher leaves. This result suggested that roughness offers UV protection, further highlighting its impact on the microbiological safety of baby leafy greens.

Beta-lactamase production and conjugative ability of multidrug resistant Salmonella Typhi in Southern Benue, Nigeria

Objective: To examine multidrug resistant (MDR) Salmonella (S.) Typhi isolates obtained from the stool samples of patients attending secondary health centers in Southern Benue, Nigeria, for extended spectrum beta-lactamase (ESBL) production and conjugative ability. Methods: The double disc synergy test was used to screen for ESBL production in MDR isolates. The ability of S. Typhi to transfer resistance gene was determined by conjugation experiments using standard protocols, with slight modifications. Escherichia (E.) coli ATCC 25922 was used as the recipient organism. Result: The donor S. Typhi isolates showed resistance to all the classes of antibiotics except aminoglycosides and carbapenems. All isolates except TKP 106, APA 55, APA 78 and OGB 106 were positive for ESBL production. Reduction in the zones of inhibition of E. coli after incubation with S. Typhi showed evidence of conjugation and transfer of antibiotic resistance from S. Typhi to E. coli. Conclusions: The presence of ESBL-producing S. Typhi capable of conjugation poses a significant risk to the treatment and management of typhoid fever, which highlights the need for the regulation of antibiotic use through relevant policies and strategies that aim at halting the spread of MDR and ESBL-producing S. Typhi in such rural settings.

Evaluation of the antimicrobial attribute of bioactive peptides derived from colostrum whey fermented by Lactobacillus against diarrheagenic E. coli strains.

Colostrum known as “liquid gold” contains approximately 60–80% of whey proteins that can be a great source of bioactive peptide production. Therefore, this study aimed to perform a comparative antimicrobial evaluation of the bioactive peptide generated from L. rhamnosus C25, L. rhamnosus C6, and L. casei NCDC17 fermented colostrum whey. Peptide fractions 10 kDa, 5 kDa, and 3 kDa were isolated using their respective molecular weight cut-off membranes and antimicrobial activity was evaluated against diarrheagenic E. coli strains. The higher inhibition was shown by < 10 kDa peptide fractions from L. rhamnosus C25 fermented colostrum whey and the zone of inhibition was 15 ± 0.06 (E. coli MTCC 723), 17 ± 0.04 (E. coli MTCC 724), 18 ± 0.05 (E. coli MTCC 725), and 17 ± 0.02 (E. coli ATCC 25922). In addition, ST-1 and LT-1 genes of E. coli strains were also confirmed using PCR which is responsible for the diarrheagenic property. Further, the interaction of potent peptides against E. coli strains was also observed by scanning electron microscope. Hence, the significance of the present study emphasized that these bioactive peptides generated from fermented colostrum whey can be used as ingredients in functional food against diarrhoea.

In Vitro Antibacterial Activity of Some Plant Essential Oils against Four Different Microbial Strains

This study evaluates the antimicrobial and antioxidant activities of five essential oils (EO): pine oil, thyme oil, sage oil, fennel oil, and eucalyptus essential oils. To identify the chemical composition of the essential oils, we used gas chromatography coupled to a mass spectrometer (GC-MS). EO are predominantly characterized by the presence of monoterpene hydrocarbons and oxygenated monoterpenes, except in the case of fennel essential oil which contains phenylpropanoids as its main components. The antimicrobial activity of the EO was highlighted on four standard microbial strains (two Gram-negative strains-Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853; one Gram-positive strain Staphylococcus aureus ATCC 25923, and one yeast strain-Candida albicans ATCC 10231). Antimicrobial activity was assessed by measuring the diameter of the inhibition zone, and by determining the values of the minimum inhibitory concentration (MIC) and minimum concentration of biofilm eradication (MCBE). Analyzing the diameter values of the inhibition zones we observed increased efficiency of thyme essential oil, which showed the highest values for all tested microbial species. The results of tests performed in a liquid confirm the high sensitivity of the standard strain Escherichia coli ATCC 25922 to the action of all essential oils, the lowest values of MIC being recorded for sage and thyme essential oils. For the most essential oils tested in this study, the MCBE values are close to the MIC values, except for the pine EO which seems to have stimulated the adhesion of the yeast strain at concentrations lower than 5%. The study highlights the antimicrobial activity of the tested essential oils on Gram-positive and Gram-negative strains.

New Amorphous Hydrogels with Proliferative Properties as Potential Tools in Wound Healing.

The study and discovery of bioactive compounds and new formulations as potential tools for promoting the repair of dermoepidermal tissue in wound healing is of continuing interest. We have developed a new formulation of amorphous hydrogel based on sodium alginate (NaAlg); type I collagen, isolated by the authors from silver carp tails (COL); glycerol (Gli); Aloe vera gel powder (AV); and silver nanoparticles obtained by green synthesis with aqueous Cinnamomum verum extract (AgNPs@CIN) and vitamin C, respectively. The gel texture of the amorphous hydrogels was achieved by the addition of Aloe vera, demonstrated by a rheological analysis. The evaluations of the cytotoxicity and cell proliferation capacity of the experimental amorphous hydrogels were performed against human foreskin fibroblast Hs27 cells (CRL-1634-ATCC). The developed gel formulations did not show a cytotoxic effect. The hydrogel variant containing AgNPs@CIN in a concentration of 8 µg Ag/gel formulation and hydrogel variant with vitamin C had proliferative activity. In addition, the antibacterial activity of the hydrogels was evaluated against S. aureus ATCC 6538, Ps. aeruginosa ATCC 27853, and E. coli ATCC 25922. The results demonstrated that the gel variant based on AgNPs@CIN in a concentration of 95 µg Ag/gel formulation and the hydrogel based on vitamin C show antibacterial activity. Therefore, the developed hydrogels with AgNPs@CIN and vitamin C could be promising alternatives in wound healing.