Growth Of Gram-negative Bacteria Research Articles

Study on the characteristics of novel fiber extracted from Foxtail palm fruits – A steps towards the sustainable development

This study explores the properties of fibers extracted from the fruits of the Foxtail palm (FPF) and assesses their potential for advancing sustainable development. Antibacterial assays demonstrated that these fibers significantly inhibit the growth of gram-negative bacteria, including Pseudomonas aeruginosa and Salmonella enterica, with inhibition zones of 24 mm and 30 mm, respectively. X-ray diffraction analysis revealed a predominantly crystalline structure, which is crucial for use as reinforcing materials, showing distinct peaks at 20° and 30° diffraction angles that signify the presence of cellulose I. Fourier-transform infrared spectroscopy confirmed the fibers’ complex composition of cellulose, hemicellulose, and lignin, indicated by the presence of hydroxyl, carbonyl, and aliphatic functional groups. Scanning electron microscopy analysis showed a rough and irregular surface texture adorned with numerous microfibrils and cavities, which are beneficial for mechanical interlocking with polymer matrices. The densely arranged cellulose microfibrils, approximately 210 µm in diameter, lend the fibers high tensile strength and stiffness. Although some surface imperfections were observed, the inherent porosity of the fibers facilitates resin absorption, enhancing their reinforcement capabilities in composite materials.

Effectiveness of Garcinia mangostana Mangosteen Peel Extract in Inhibiting Gram-Negative Bacteria in Lobster (Panulirus homarus) Aquaculture Waters

This study aims to examine the effectiveness of mangosteen peel extract (Garcinia mangostana) in inhibiting the growth of Gram-negative bacteria in lobster (Panulirus homarus) aquaculture waters. The main problem in lobster farming is bacterial infections that can cause disease and mass mortality. Mangosteen peel extract is known to contain potent antimicrobial compounds. This research employs an experimental method with various concentrations of mangosteen peel extract to test its effect on the growth of Gram-negative bacteria. Based on result, the mangosteen peel inhibition zone against Gram-negative bacteria from lobster aquaculture waters measures 0.25±0.05 cm (25 mm), indicating weak inhibition activity. This suggests that mangosteen peel could be used as an immunostimulant alternative to antibiotics in combating diseases in lobsters. Further research is needed to determine the optimal dosage of mangosteen peel extract to achieve strong inhibition activity against bacteria.

Study of antibacterial effects of Transcarpathian clinoptilolite compositions modified in different chemical ways

Background. Natural clinoptilolite (CL) meets most of the requirements for the multifunctional mineral nanomaterials. It is considered biologically neutral and non-toxic. CL is the only representative of natural zeolites that has been approved for use in medical practice and food industry. Antibacterial activity of Transcarpathian clinoptilolite was shown to be enhanced via its modification using thermal, chemical and mechanochemical treatments. The natural form of this mineral contains a significant concentration of surface silanol (-OH) groups. An increase in the efficiency of zeolite-based materials in terms of biological activity can be achieved by means of thermal and chemical treatments, replacement of cations in the exchange complex, doping with heavy metal cations, or mechanochemical treatment. Materials and Methods. FTIR spectroscopy, Electronic spectroscopy, Particle size distribution, IR spectroscopy, Crystal structure and morphology, Measurement of antibacterial activity. Results. Intact and thermally modified CL was shown to exhibit weak antibacterial effect, while its mechanical modification led to an enhanced activity. It was established that H-form of clinoptilolite demonstrated higher efficiency in inhibiting the growth of Gram-positive bacteria, compared to the Na-form of the clinoptilolite, but their effect on growth of Gram-negative bacteria was insignificant. Such an activity was accompanied by an increase in the specific surface area and porosity that promoted better contact with bacteria. Conclusions: Different samples of CL had dissimilar effect on specific types of bacteria. Intact CL has a weak antibacterial activity of inhibiting growth of microorganisms, while thermal, chemical, and mechanical modifications of the CL structure differentially increased such an activity. The H-form of CL inhibited the growth of Gram-positive bacteria (Staphylococcus aureus, Bacillus subtilis) more effectively compared to the Na-form of CL. However, H-form of CL has a weak effect on growth of the Gram-negative bacteria (Pseudomonas aeruginosa, Pseudomonas fluorescens).

Peptides with Antimicrobial Activity in the Saliva of the Malaria Vector Anopheles coluzzii.

Mosquito saliva plays a crucial physiological role in both sugar and blood feeding by helping sugar digestion and exerting antihemostatic functions. During meal acquisition, mosquitoes are exposed to the internalization of external microbes. Since mosquitoes reingest significant amounts of saliva during feeding, we hypothesized that salivary antimicrobial components may participate in the protection of mouthparts, the crop, and the gut by inhibiting bacterial growth. To identify novel potential antimicrobials from mosquito saliva, we selected 11 candidates from Anopheles coluzzii salivary transcriptomic datasets and obtained them either using a cell-free transcription/translation expression system or, when feasible, via chemical synthesis. Hyp6.2 and hyp13, which were predicted to be produced as propeptides and cleaved in shorter mature forms, showed the most interesting results in bacterial growth inhibition assays. Hyp6.2 (putative mature form, 35 amino acid residues) significantly inhibited the growth of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli and Serratia marcescens) bacteria. Hyp13 (short form, 19 amino acid residues) dose-dependently inhibited E. coli and S. marcescens growth, inducing membrane disruption in both Gram-positive and Gram-negative bacteria as indicated with scanning electron microscopy. In conclusion, we identified two A. coluzzii salivary peptides inhibiting Gram-positive and Gram-negative bacteria growth and possibly contributing to the protection of mosquito mouthparts and digestive tracts from microbial infection during and/or after feeding.

Levels of IL-6 and IL-8 in Complicated versus Uncomplicated Urinary Tract Infection

Urinary tract infections (UTIs) are one of the world's most frequent infectious diseases, affecting 150 million people each year and resulting in severe morbidity and high medical expenditures. UTIs can be clinically defined as uncomplicated UTIs (uUTIs) or complicated UTIs (cUTIs) to differentiate infections of benign origin from those with a higher risk of recurrence or progression to severe pathology. The aim of this study was to evaluate interleukin-6 (IL-6) and IL-8 as potential biomarkers in differentiating complicated and uncomplicated. Ninety samples of urine were collected. There were 43 samples from healthy controls and 47 samples from UTI patients—those who have been clinically diagnosed with UTIs by the urologist. The serum IL-6 and IL-8 were measured using an enzyme-linked immunosorbent assay and commercially available kits. The levels of both IL-6 and IL-8 were significantly higher in UTI patient then in control subjects (p=0.001, p=0.001). A significant difference was observed in the mean of level IL-6 between culture positive UTI patients and culture negative UTI patients (p=0.014). In addition, the type of bacterial growth, a significant difference was observed in the mean of serum IL-6 and IL-8 level in UTI caused by gram negative bacteria in comparison with UTI caused by gram positive bacteria. High levels of IL-6 are associated with the growth of gram-negative bacteria, and this indicates that gram-negative bacteria could induce stronger inflammatory responses than gram-positive bacteria. IL-8 levels are higher in UTIs caused by gram-negative bacteria. This result further supported the evidence that gram-negative bacteria are potent inducers of inflammatory responses.

First Report of Ocellatin-VT from the Skin Secretion of Leptodactylus vastus Lutz (Amphibia: Leptodactylidae)

The global emergency of antimicrobial resistance has drawn several efforts to evaluate new drug candidates, such as natural defensive biomolecules. Ocellatins are a group of antimicrobial peptides found in anurans of the Leptodactylidae family. This work investigated the presence of antimicrobial peptides in the skin secretion of Leptodactylus vastus from the Brazilian northeast. The secretion was fractionated by RP-HPLC, and the fractions were screened for antibacterial activity. A peptide isolated from the most active fraction was characterized for primary structure and evaluated for antibacterial activity, cytotoxicity to murine melanoma cells (B16-F10), and hemolytic activity. The RP-HPLC profile displayed 26 fractions, with fraction 25 being the most active. One of the two peptides present in this fraction had the primary structure determined, belonging to the group of ocellatins. Since it was not identical to other ocellatins previously reported, it was named ocellatin-VT. This peptide especially inhibited Gram-negative bacteria growth, with the highest activity against Acinetobacter baumannii and Escherichia coli (growth inhibition was higher than 95% at 8 and 16 µM, respectively). Ocellatin-VT was weakly cytotoxic to B16-F10 cells and showed low hemolytic activity. In conclusion, a new ocellatin was isolated from L. vastus skin secretion that was active against non-resistant and multidrug-resistant bacteria.

Identification of Novel Antimicrobial Compounds Targeting Mycobacterium tuberculosis S-Adenosyl-L-Homocysteine Hydrolase Using Dual Hierarchical In Silico Structure-Based Drug Screening.

The emergence of multidrug-resistant and extensively drug-resistant Mycobacterium tuberculosis (M. tuberculosis) has become a major medical problem. S-adenosyl-L-homocysteine hydrolase (MtSAHH) was selected as the target protein for the identification of novel anti-TB drugs. Dual hierarchical in silico Structure-Based Drug Screening was performed using a 3D compound structure library (with over 150 thousand synthetic chemicals) to identify compounds that bind to MtSAHH's active site. In vitro experiments were conducted to verify whether the nine compounds selected as new drug candidates exhibited growth-inhibitory effects against mycobacteria. Eight of the nine compounds that were predicted by dual hierarchical screening showed growth-inhibitory effects against Mycobacterium smegmatis (M. smegmatis), a model organism for M. tuberculosis. Compound 7 showed the strongest antibacterial activity, with an IC50 value of 30.2 µM. Compound 7 did not inhibit the growth of Gram-negative bacteria or exert toxic effects on human cells. Molecular dynamics simulations of 40 ns using the MtSAHH-Compound 7 complex structure suggested that Compound 7 interacts stably with the MtSAHH active site. These in silico and in vitro results suggested that Compound 7 is a promising lead compound for the development of new anti-TB drugs.

Single NIR laser-activated synergistic low-temperature photothermal therapy and self-oxygenated photodynamic therapy nano-platforms for bacteria infection

The emergence and spread of drug-resistant bacterias with new resistance mechanisms leads to antimicrobial resistance and continues to threaten our ability to treat common infections. Herein, a nano-platform (PB@MnO2@MB@HA) was provided to bring significant bacterial inhibition via win-win photo-combination therapy strategy mediated by a single wavelength. More importantly, with well photothermal conversion efficiency, the nano-platform enables effective low temperature photothermal therapy (below 42 °C), where the heat generated is advantageous for the advancement of photodynamic therapy. Moreover, the addition of manganese dioxide promotes the supply of oxygen and addresses the limitations of low-oxygen environments on photodynamic therapy, further enhancing its therapeutic effect, which in turn compensates for the efficacy of low temperature photothermal. The nano-platform can effectively inhibit the growth of Gram-negative bacteria with an inhibition rate of 99%. In summary, the combined therapy of low-temperature photothermal therapy and self-oxygenated photodynamic therapy synergistically improves the efficacy of bacteria treatment while reducing the side effects associated with two therapy alone. The photo-combination nano-platform triggered by single wavelength near infrared irradiation has significant clinical application potential in overcoming the limitations of monotherapy for bacterial infection.

A novel thermophilic strain of Bacillus subtilis with antimicrobial activity and its potential application in solid-state fermentation of soybean meal.

Soybean meal (SBM) is the most important source of plant protein in animal feeds, containing around 41%-48% crude protein. Nevertheless, 70%-80% of these proteins is allergenic antigens that can have adverse implications for the gastrointestinal well-being of animals, especially to young animals. Microbial fermentation is one of the most cost-effective strategies used to reduce allergenic antigens from plant sources. In this study, we report the isolation and characterization of a novel probiotic Bacillus subtilis "L5" strain from lake mud. L5 demonstrated remarkable temperature tolerance across a broad temperature spectrum, thriving at 25°C, 37°C, and 50°C. In addition, antimicrobial assay revealed that L5 exhibits strong antimicrobial activity against Escherichia coli, effectively reducing or eliminating the growth of Gram-negative bacteria in SBM when fermented with L5. When applied to SBM fermentation, L5 efficiently reduced SBM antinutritional factors such as glycinin, β-conglycinin, trypsin inhibitor, phytic acid, neutral detergent fiber, and acid detergent fiber, which in turn results in an increase in crude protein content and the free amino acid concentration. Our findings on the probiotic and fermentation capabilities of L5 suggest that this novel bacterium has dual functions that make it a strong candidate for improving the nutrient values of feed via its role in fermentation.IMPORTANCESoybean meal (SBM), containing 41%-48% crude protein, is the most important source of plant protein in animal feeds. Unfortunately, 70%-80% of the proteins in SBM is allergenic antigens including trypsin inhibition, β-conglycinin, and conglycinin, which negatively affect intestine health and function. Microbial solid-state fermentation methods have been applied to animal feeds for decades, to eliminate antinutritional factors. Here, a novel potential probiotic Bacillus subtilis "L5" strain with high enzymatic activity and antimicrobial activity will be a great help to improve the quality and reproducibility of SBM fermentation.

Mango Peels as an Industrial By-Product: A Sustainable Source of Compounds with Antioxidant, Enzymatic, and Antimicrobial Activity.

Plant waste materials are important sources of bioactive compounds with remarkable health-promoting benefits. In particular, industrial by-products such as mango peels are sustainable sources of bioactive substances, with antioxidant, enzymatic, and antimicrobial activity. Appropriate processing is essential to obtain highly bioactive compounds for further use in generating value-added products for the food industry. The objective of the study was to investigate and compare the biological activity of compounds from fresh and dried mango peels obtained by different conventional methods and unconventional extraction methods using supercritical fluids (SFE). The highest total phenolic content (25.0 mg GAE/g DW) and the total content of eight phenolic compounds (829.92 µg/g DW) determined by LC-MS/MS were detected in dried mango peel extract obtained by the Soxhlet process (SE). SFE gave the highest content of proanthocyanidins (0.4 mg PAC/g DW). The ethanolic ultrasonic process (UAE) provided the highest antioxidant activity of the product (82.4%) using DPPH radical scavenging activity and total protein content (2.95 mg protein/g DW). Overall, the dried mango peels were richer in bioactive compounds (caffeic acid, chlorogenic acid, gallic acid, catechin, and hesperidin/neohesperidin), indicating successful preservation during air drying. Furthermore, outstanding polyphenol oxidase, superoxide dismutase (SOD), and lipase activities were detected in mango peel extracts. This is the first study in which remarkable antibacterial activities against the growth of Gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa) and Gram-positive bacteria (Bacillus cereus and Staphylococcus aureus) were evaluated by determining the microbial growth inhibition rate after 12 and 24 h incubation periods for mango peel extracts obtained by different methods. Ethanolic SE and UAE extracts from dried mango peels resulted in the lowest minimum inhibitory concentrations (MIC90) for all bacterial species tested. Mango peels are remarkable waste products that could contribute to the sustainable development of exceptional products with high-added value for various applications, especially as dietary supplements.

Assessment of mycotoxin sequestration efficacy in Saccharomyces cerevisiae by-products cultured in wheat bran and whey protein medium

Mycotoxins are metabolic products of fungi found in feed for farm animals and pose a major threat to food safety due to their adverse health effects. The development of strategies to reduce their bioavailability is crucial. In this context, the cell wall components of Saccharomyces cerevisiae (YCW), especially β-d-glucans and Mannan-oligosaccharide, have been recognized as potent mycotoxin binders. The objective of this research was to develop a novel culture medium to increase the biomass yield of S. cerevisiae and optimize cell disruption by stepwise physical lysis and hydrolytic preconditioning. This process resulted in a yield of approximately 56% reducing saccharides and 28.54% protein. Subsequently, the β-glucan was extracted after cell wall sequestration. The isolated YCW and extracted β-glucan were characterized both individually and synergistically to evaluate their antibacterial properties and analyze their Fourier transform infrared (FTIR) spectra. In vitro evaluation of antibacterial activity revealed that a concentration greater than 250 μg/mL of YCW-β-glucan blend significantly inhibited the growth of Gram-negative bacteria. In addition, this blend showed good adsorption of various mycotoxins, including Aflatoxin B1, Ochratoxin A, and Zearalenone, the latter of which exhibited a remarkable adsorption rate of 80.85%. This study highlights the promising potential of a combination of YCW and β-glucan as a robust strategy to address the pervasive problem of mycotoxin contamination in feed.

Early Switch From Intravenous to Oral Antibiotics for Patients With Uncomplicated Gram-Negative Bacteremia

Gram-negative bacteremia is a global health concern, and optimizing the transition from intravenous (IV) to oral antibiotics is a critical step in improving patient treatment and resource utilization. To assess the association of switching to oral antibiotics within 4 days after initial blood culture with 90-day all-cause mortality compared with prolonged IV antibiotic treatment for patients with uncomplicated gram-negative bacteremia. This cohort study conducted using the target trial emulation framework included observational data from adults with uncomplicated gram-negative bacteremia in 4 hospitals in Copenhagen, Denmark, from January 1, 2018, through December 31, 2021. The duration of follow-up was 90 days. Eligibility criteria included a blood culture positive for growth of gram-negative bacteria, clinical stability within 4 days of initial blood culture, an available susceptibility report on day 4, and initiation of appropriate empirical IV antibiotic treatment within 24 hours of blood culture. Switching to oral antibiotics within 4 days after initial blood culture compared with continuing IV antibiotic treatment for at least 5 days after initial blood culture. The main outcome was 90-day all-cause mortality. Inverse probability of treatment weighting was applied to adjust for confounding. Intention-to-treat and per-protocol analyses were performed using pooled logistic regression to estimate absolute risk, risk difference (RD), and risk ratio (RR); 95% CIs were computed using bootstrapping. A total of 914 individuals were included in the target trial emulation analysis (512 [56.0%] male; median age, 74.5 years [IQR, 63.3-83.2 years]); 433 (47.4%) transitioned early to oral antibiotic treatment, and 481 (52.6%) received prolonged IV treatment. Ninety-nine individuals (10.8%) died during follow-up. The proportion of individuals who died was higher in the group receiving prolonged IV treatment (69 [14.3%] vs 30 [6.9%]). In the intention-to-treat analysis, 90-day all-cause mortality risk was 9.1% (95% CI, 6.7%-11.6%) for the early-switch group and 11.7% (95% CI, 9.6%-13.8%) for the group receiving prolonged IV treatment; the RD was -2.5% (95% CI, -5.7% to 0.7%) and RR was 0.78 (95% CI, 0.60-1.10). In the per-protocol analysis, the RD was -0.1% (95% CI, -3.4% to 3.1%) and RR was 0.99 (95% CI, 0.70-1.40). In this cohort study of uncomplicated gram-negative bacteremia, early transition to oral antibiotics within 4 days of initial blood culture was associated with 90-day all-cause mortality risk comparable to that of continuing IV antibiotic treatment and may be an effective alternative to prolonged IV treatment.

Cationic and amphiphilic peptide-based hydrogels with dual activities as anticancer and antibacterial agents.

The emergence of peptide-based functional biomaterials is on the rise. To fulfil this purpose, a series of amphiphilic peptides, such as H2N-X-Met-Phe-C12H25, where X = L-lysine (CP1), X = L-histidine (CP2), and X = L-leucine (CP3), have been designed, synthesised, purified and fully characterised. Herein, we reported peptide-based supramolecular hydrogels with antibacterial and anticancer activities. An attempt has been made to investigate the antibacterial properties of these peptide-based hydrogels against Gram-positive (S. aureus and B. subtilis) and Gram-negative (E. coli and P. aeruginosa) bacteria. Investigations show that the L-lysine containing gelator, CP1, is active against both Gram-positive and Gram-negative bacteria and the L-histidine containing gelator, CP2, selectively inhibits the growth of Gram-negative bacteria. Interestingly, the L-leucine containing gelator, CP3, does not show any antibacterial properties. Moreover, the L-lysine containing gelator exhibits the best potency. Generation of reactive oxygen species (ROS) is a probable way to damage the bacterial membrane. To explore the cytotoxic properties and to determine the efficacy of the synthesized compounds in inhibiting cell viability, a comprehensive investigation was performed using three distinct cell lines: MDA-MB-231 (human triple-negative breast cancer), MDA-MB-468 (human triple-negative breast cancer) and HEK 293 (human embryonic kidney). Remarkably, the results of our study revealed a substantial cytotoxic impact of these peptide gelators on the MDA-MB-231 and MDA-MB-468 cell lines in comparison to the HEK 293 cells. Caspase 3/7 activity is the possible mechanistic path to determine the apoptotic rates of the cell lines. This finding emphasizes the promising potential of these peptide-based gelators in targeting and suppressing the growth of human triple negative breast cancer cells, while showing non-cytotoxicity towards non-cancerous HEK 293 cells. In a nutshell, these peptide-based materials are coming to light as next generation biomaterials.

Electrospun cellulose nanofibers immobilized with anthocyanin extract for colorimetric determination of bacteria

A novel smart biochromic textile sensor was developed by immobilizing anthocyanin extract into electrospun cellulose acetate nanofibers to detect bacteria for numerous potential uses, such as healthcare monitoring. Red-cabbage was employed to extract anthocyanin, which was then applied to cellulose acetate nanofibers treated with potassium aluminum sulfate as a mordant. Thus, nanoparticles (NPs) of mordant/anthocyanin (65–115 nm) were generated in situ on the surface of cellulose acetate nanofibrous film. The pH of a growing bacterial culture medium is known to change when bacteria multiply. The absorbance spectra revealed a bluish shift from 595 nm (purple) to 448 nm (green) during the growth of Gram-negative bacteria (E. coli) owing to the discharge of total volatile basic amines as secretion metabolites. On the other hand, the absorption spectra of a growing bacterial culture containing Gram-positive bacteria (L. acidophilus) showed a blue shift from 595 nm (purplish) to 478 nm (pink) as a result of releasing lactic acid as a secretion metabolite. Both absorbance spectra and CIE Lab parameters were used to determine the color shifts. Various analytical techniques were utilized to study the morphology of the anthocyanin-encapsulated electrospun cellulose nanofibers. The cytotoxic effects of the colored cellulose acetate nanofibers were tested.

The Effect of Silver and Samarium on the Properties of Bioglass Coatings Produced by Pulsed Laser Deposition and Spin Coating.

The current study reports the use of silver (Ag) and samarium (Sm) as dopants to improve the properties of standard bioglass in terms of biological performance. This experiment considers thin films of doped bioglass obtained by pulsed laser deposition (PLD) and spin coating (SC). For both methods, some parameters were gradually varied, as the main objective was to produce a bioglass that could be used in biomedical fields. In order to study the morphology, the phase composition and other properties, the samples obtained were subjected to multiple analyses, such as thermal analysis, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), Fourier-transform infrared (FT-IR), Raman spectroscopy, and x-ray diffraction (XRD). Furthermore, the in vitro bioactivity of the samples, as assessed through simulated body fluid (SBF) immersion, as well as immunocytochemistry and evaluation of actin filaments, assessed through fluorescence microscopy, are reported. The results confirmed the formation of the designed vitreous target employed as the source of material in the PLD experiments only at sintering temperatures below 800 °C; this vitreous nature was preserved in the grown film as well. The presence of Ag and Ce dopants in the parent glassy matrix was validated for all stages, from powder, to target, to PLD/SC-derived coatings. Additionally, it was demonstrated that the surface topography of the layers can be adjusted by using substrates with different roughness or by modulating the processing parameters, such as substrate temperature and working pressure in PLD, rotation speed, and number of layers in SC. The developed material was found to be highly bioactive after 28 days of immersion in SBF, but it was also found to be a potential candidate for inhibiting the growth of Gram-negative bacteria and a suitable support for cell growth and proliferation.

Chlamydomonas reinhardtii-derived triple BmKbpp distorts membrane integrity for inhibiting bacterial growth

Antibiotic abuses cause pathogen resistance to conventional antibiotics, threating public health globally. Antimicrobial peptides were considered as substitutes for antibiotic because of their broaden and rapid antibacterial activity. BmKbpp extracted from the Chinese scorpion Mesobuthus martensii Karsch inhibits the growth of gram-negative bacteria and fungi efficiently, while its efficacy for inhibiting the growth of the gram-positive Staphylococcus aureus was limited. Besides, how BmKbpp inhibits bacterial growth remains elusive thus far. In this study, a C-terminal hemagglutinin (HA) and 6×His (HA-6×His) tagged BmKbpp of three repeats (3×BmKbpp) was expressed in Chlamydomonas reinhardtii. The recombinant 3×BmKbpp-HA-6×His exhibited antibacterial activity against both gram-positive and gram-negative bacteria with a minimum inhibitory concentration between 20⁓200 µg/ml. The minimum bactericidal concentration ranged from 1 × MIC to 3 × MIC for 3×BmKbpp-HA-6×His. 3×BmKbpp-HA-6×His exhibited a good thermostability and resisted on pH shock and digestion of certain proteinases. It also displayed low cytotoxicity and hemolysis as tested on cell lines including HEK293, Vero, MDCK, and BHK-21. In addition, 3×BmKbpp-HA-6×His inhibits bacterial growth by effectively distorting bacterial cell membrane. Thus, C. reinhardtii-derived 3×BmKbpp-HA-6×His effectively inhibits bacterial growth, making it a promising antimicrobial peptide.

Влияние Lactobacillus acidophilus на рост биопленок в подсырной сыворотке

The modeling of the biofilms formation in cheese whey on glass under static conditions including with Lactobacillus acidophilus was carried out. Biofilm development in cheese whey is faster than in its ultrafiltration permeate. The basis of the three-dimensional structure of a mature biofilm is made up of representatives of the genera included in the group of sanitary indicative microorganisms. Yeasts are involved in all stages of biofilm formation. L. acidophilus cells of the «BK-Uglich-AV» starter actively integrate into the biofilm structure, inhibiting the growth of gram-negative bacteria and contributing to the destruction of the exopolysaccharide layer, but without affecting yeast. The data obtained can be used both for the development of biofilm control methods in the dairy industry and for biotechnological purposes.

THE CONTINUING MENACE OF EXTENDED SPECTRUM BETA LACTAMASE (ESBLS) - A CENTRE BASED STUDY

Abstract:
 Objective: To determine the occurrence of Extended-spectrum β-lactamase (ESBL) producing gram negative bacteria (GNB) and their sensitivity patterns in a tertiary care hospital.
 Methods: In this cross-sectional study, conducted in the Microbiology section of Pathology lab, in a tertiary care hospital Lahore, various specimens such as blood, body fluids, urine, and pus were included during a period starting from October 2020 till September 2021. The samples having growth of gram negative bacteria were processed further for determination of ESBL production. After isolation, antimicrobial susceptibility pattern was determined for each isolate.
 Results: GNB were isolated from 130 samples, among those 46 (35.4%) were labelled as ESBL. The commonest ESBL producing bacteria was E. coli, followed by pseudomonas aeruginosa found in 17.39% samples. In E. Coli, Imipenem (IPM) showed highest sensitivity of 84.8%, other sensitive drugs were Amikacin (AK), gentamicin (CN), and Tazobactam-piperacillin(TZP). For Pseudomonas aeruginosa, Imipenem and Tazobactam-piperacillin showed sensitivity of 75%, AK and CN were 50% sensitive. Against Klebsiella pneumoniae , IPM was 100% sensitive, AK and TZP were 85.7% sensitive. IPM, CN, and AK were 100% sensitive against Morganella morganii. AK and CN were 100% sensitive against Citrobacter species.
 Conclusion: It was concluded that, there was significant prevalence of ESBL producing strains amongst Gram negative bacterial infections. E. Coli and Pseudomonas aeruginosa were the commonest ESBL producers. IPM, AK, and TZP were sensitive against majority of the ESBL producing GNB.

Study of in vitro antioxidant and antibacterial potential of different tea clones

BackgroundCamellia sinensis (L.) O. Kuntze (tea) belongs to the family of Theaceae and is one of the most popular beverages. According to traditional Chinese medicine, its phytochemicals have the ability to cure various diseases of the liver, heart, spleen, and lungs. This study was done to explore the phytochemical potentiality of leaf extracts from different tea clones with special emphasis on their antioxidant, total phenol, flavonoid, and antibacterial activity. MethodsThe leaves were extracted in methanol for various qualitative, and quantitative tests like antioxidant assay, total phenolic content, flavonoid content etc. ResultsThe result of this study delivers comparative data about the biochemical properties of various tea clones which will further help in future studies. Leaves extract of tea clones like TV-9, TV-26, CP-1 and Phoobsering-312 showed promising antioxidant activity. Leaves extract of TV-9, TV-23, TV-26 and CP-1 has shown an inhibitory effect on the growth of Gram-negative bacteria Escherichia coli. Among the clones, Phoobsering-312 was found to be the most prominent tea clone as it exhibited total phenolic content, and antioxidant properties along with very significant antibacterial activity against Escherichia coli and Bacillus subtilis. ConclusionThis study showed the Darjeeling Garden clone (Phobsering-312) could be selected as an ideal clone for cultivation in the study area. This is to sustain the phytochemical quality of tea and gain health benefits, as the quality of manufactured tea is reflected in all aspects of the green harvest.

The prevalence of Carbapenem Resistance Gram negative pathogens in a Tertiary Teaching Hospital in Jordan

BackgroundWith the absence of new antimicrobial drugs being developed to replace those facing resistance, bacterial resistance continues to grow. Despite previous studies conducted in various countries, there is a lack of comprehensive local reporting on the occurrence of carbapenem resistance among gram-negative bacteria.ObjectiveThis study aims to identify the prevalence of carbapenem-resistant gram-negative bacterial isolates.MethodA retrospective cross-sectional study was conducted at an academic hospital in Jordan over an eight-month period, spanning from November 2021 to June 2022. The study involved screening electronic medical records to identify patients with clinical cultures showing the growth of Gram-negative bacteria. Antimicrobial susceptibility results of the Gram-negative isolates were recorded.ResultsA total of 1,043 isolated Gram-negative bacteria were analyzed for carbapenem susceptibility. Among the species tested, the most common carbapenem-resistant bacteria were Acinetobacter baumannii (153/164, 93.3%), followed by Klebsiella pneumonia (184/311, 59.2%), and Pseudomonas aeruginosa (67/160, 41.9%). The least commonly isolated species resistant to carbapenem were Escherichia coli (25/361, 6.9%) and Proteus mirabilis (1/30, 3.3%). None of Serratia marcescens or Proteus vulgaris isolates were resistant to carbapenem (0%). Overall, the prevalence of carbapenem-resistance gram-negative isolates was 41.2% (430 out of 1,043).ConclusionThis study provides population-specific data that are crucial for guiding empirical antimicrobial treatment decisions not only within the participating hospital but also in other nearby healthcare facilities. The results underscore the urgent need for coordinated efforts to address antibiotic resistance in Jordan. Comprehensive measures such as strict infection control methods, annual nationwide surveillance programs, and effective antimicrobial stewardship programs at the national level are imperative to reduce the overuse of broad-spectrum antibiotics.