Vajid Nettoor Veettil

Objective: The objective of this review is to synthesize qualitative evidence on the perceptions of health care professionals and policymakers regarding barriers and facilitators to implementing antimicrobial stewardship (AMS) programs in hospital settings, particularly in low- and middle-income countries. Introduction: AMS programs are widely recognized as critical interventions to combat antimicrobial resistance and optimize the use of antibiotics. While quantitative studies have demonstrated the effectiveness of AMS programs in reducing inappropriate antibiotic use, less is known about the experiences, perceptions, and contextual factors that influence their implementation and sustainability. Eligibility criteria: This review will include qualitative studies exploring the experiences, perceptions, attitudes, and contextual factors influencing implementation of AMS programs among health care professionals and policymakers. Studies conducted in any health care setting and involving any population relevant to AMS programs will be considered. Methods: The key information sources to be searched for this review will include PubMed, CINAHL (EBSCOhost), PsycINFO (Ovid), Scopus, Embase, and Web of Science Core Collection. The search will include studies published in any language from 2015 onward. Study selection will be conducted independently by 2 reviewers, with any disagreements resolved through discussion or consultation with a third reviewer. All included studies will be critically appraised for methodological quality, and all will proceed to synthesis, regardless of the results of methodological quality assessment. Data relevant to the review objectives will be extracted in terms of both findings and illustrations, followed by an aggregative data synthesis approach. Confidence in the findings will be assessed using a structured grading process based on credibility and dependability. Review registration: PROSPERO CRD420251044164

Terminalia arjuna, an important medicinal plant in traditional Indian systems, has been extensively studied for its cardioprotective bark. However, limited attention has been given to its fruit, which contains several biologically active phytochemicals with potential antioxidant, anti-inflammatory, and immunomodulatory properties. This study aimed to isolate and partially purify phytoactive compounds from the fruit of T. arjuna using chromatographic techniques, characterize them, and assess their effect on the growth of industrially important fungal strains. Dried and powdered T. arjuna fruit was extracted using 70% methanol. The crude extract was subjected to sequential solvent partitioning followed by column chromatography. The resulting fractions were evaluated using TLC, High Performance Liquid Chromatography (HPLC), and LC-MS for partial purification and confirmation of the phytochemicals. The growth-promoting effect of the purified compound was tested on Trichoderma harzianum by measuring optical density after 48 hours of incubation in the presence of the compound. Methanolic extraction of T.arjuna fruit yielded approximately 1652 mg of dried extract. Column chromatography followed by TLC profiling led to the identification of three pooled fractions (A, B, and C), each with distinct banding patterns and Rf values. Among them, Fraction B exhibited a prominent TLC band at Rf 0.133 and was the most abundant (421 mg). HPLC analysis confirmed the high purity of Fraction B, showing a single dominant peak at retention time 3.113 minutes with an area percentage of 97.8%. In growth promotion assays using Trichoderma harzianum, Fraction B significantly enhanced fungal biomass, with a 32.54% increase in OD600 compared to control. LC-MS analysis in positive ion mode identified a molecular ion at m/z 415 [M+H]+ and a key fragment at m/z 256, consistent with β-sitosterol. The presence of β-sitosterol in fruit of T. arjuna reflects the plant’s long-recognized therapeutic significance and is associated with various beneficial pharmacological effects. This study established that the fruit of T. arjuna can serve as a viable source of β-sitosterol, which may have potential as a natural growth enhancer for industrial fungi.

Purpose/Background: This study aimed to isolate, purify, and characterize a novel bacteriocin produced by Lactobacillus casei strain GO3, isolated from goat milk. Bacteriocins are promising natural antimicrobial agents with potential applications in food preservation and therapeutics, addressing growing concerns over antibiotic resistance and synthetic preservatives. Materials and Methods: L. casei GO3 was isolated from goat milk and screened for antimicrobial activity. The strain was identified through 16S rRNA sequencing, and the sequence was deposited in the NCBI database (accession number ON059683). Purification: The bacteriocin was purified using a multi-step process involving 60% ammonium sulfate precipitation, dialysis (1 kDa cutoff), and ion-exchange chromatography (diethyl aminoethyl-cellulose). Antimicrobial activity was assessed against several pathogens ( Bacillus subtilis, Escherichia coli, Salmonella typhi , and Pseudomonas aeruginosa ) using the agar well diffusion method. Stability was evaluated under various conditions, including pH (2–12), temperature (30°C–121°C), enzymes (trypsin, pepsin, and protease K), and chemicals (ethylenediaminetetraacetic acid (EDTA), urea, NaCl, and dimethyl sulfoxide). Results: The purification process yielded a 2.66% recovery rate with a 54.9-fold increase in specific activity (1,220.89 AU/mg). The bacteriocin demonstrated broad-spectrum inhibition (zone diameters >15 mm) and stability across a wide pH range (2–12) and temperatures up to 100°C. However, activity was lost at 121°C and with proteolytic enzymes, confirming its proteinaceous nature. Notably, EDTA enhanced antimicrobial activity, suggesting metal ion dependence. Conclusion: The bacteriocin produced by L. casei GO3 exhibits robust stability and potent antimicrobial efficacy, making it a promising candidate for applications in food preservation and therapeutics. Future research should focus on optimizing production and evaluating safety for industrial use.

Lactic acid bacteria (LAB) bacteriocins are renowned for their broad spectrum of antimicrobial activity. These organisms are generally recognized as safe and are predominantly utilized in food preservation, effectively suppressing harmful bacteria. The present study aims to isolate LAB from goat milk, purify bacteriocins and analyze its therapeutic applications. Of the 26 isolates, isolate GO3 showing enhanced antimicrobial activity against food-borne pathogens was identified using 16s rRNA sequencing. The organism was identified as Lactobacillus casei GO3 with 100% similar to Lactobacillus casei strain NR115322.1. Cystathionine gamma-synthase gene (MetB) with high homology to Lacticaseibacillus casei strain MetB gene was detected in the isolate GO3. The partially purified bacteriocin from Lactobacillus casei GO3 demonstrated a broad spectrum of antibacterial activity, achieving 76.4% inhibition against Gram-positive B. subtilis and 46.2% against Gram-negative Salmonella typhi and antifungal activity, with maximum against Phytophthora infestans (47.7%) and a minimum against Fusarium oxysporum (42.2%). In addition to its antimicrobial activities, the bacteriocin demonstrated significant anti-inflammatory, α-amylase inhibition, antioxidant and anticancer activity. Further studies are required to analyze its mechanism of action and potential therapeutic applications in real-world scenarios.

The catheter associated urinary tract infections (CAUTI) are gaining much attraction due to their high rate of morbidity and mortality. Therefore, urgent for alternative antimicrobial agent to fight against CAUTI. However, in the study Gymnema sylvestre methanolic crude extracts antimicrobial activity and antibiofilm activity were investigated against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis and Candid albicans. The antimicrobial activity was studied through agar diffusion method which showed potent antimicrobial activity against test pathogens. The very minimal inhibitory concentrations of G. sylvestre methanolic crude extract was detected using micro dilution method and exhibited 1 mg/ml was required for S. aureus, E. coli, E. faecalis inhibition and 2 mg/ml against C. albicans. Moreover, the anti-biofilm activity was quantified through crystal violet assay wherein the G. sylvestre methanolic crude extract effectively inhibited the test pathogens biofilm formation upto their MIC level. Also, the effect of G. sylvestre methanolic crude extract was investigated on test pathogens mature biofilms and efficiently eradicated the 85%, 88%, 81% and 84% of S. aureus, E. faecalis, E. coli and C. albicans biofilms correspondingly. The G. sylvestre methanolic crude extract coated catheter tube antimicrobial activity was studied through in vitro bladder model and exposed potent activity against test pathogens. The G. sylvestre methanolic crude extract antioxidant property was studied and the extract was not revealed any cytotoxic effect to normal cells. Altogether, the antimicrobial and anti-biofilm activity of G. sylvestre methanolic crude extract suggested that it can be an alternative agent for CAUTI treatment.

This study aims to present knowledge on therapeutic potential bacteriocin producing bacterial strains. Samples (n=35) from diverse Ernakulam sources yielded 26 lactic acid bacteria (LAB) isolates on De Man Rogosa Sharpe (MRS) medium. Among the isolates potent antimicrobial activity observed against known pathogens in one of the isolates from goat milk sample number 3, labelled as GO3. Microscopic and biochemical test revealed the isolate is Gram-positive rod, non-sporulating and resilience to pH and bile salts, with adaptability to gastric enzymes and surfactants. Genetic and physiological traits of the positive strains were confirmd by 16S rRNA technique. Blast analysis revealed that sequence of the strain GO3 from goat milk identified as Lactobacillus casei, exhibited antibiotic sensitivity, auto-aggregation, co-aggregation, and antibiofilm assays highlighted inhibitory properties as a promising therapeutic potential probiotic bacterium. LAB isolates can be further investigated at the genetic level to enhance their probiotic characteristics such as resistance and cellular adhesion. Additionally, the identification of gene responsible for expressing bacteriocins can be conducted on these isolates.

The cytotoxic, antioxidant, anticancer, and antibacterial properties of ethanolic extracts from Phragmanthera austroarabica is of interest. Plants of P. austroarabica were gathered from the southern Saudi Arabian region of Albaha. P. austroarabica extract was assessed using DPPH (2, 2-diphenyl-1-picrylhydrazyl). The German Collection of Microorganisms and Cell Cultures (DSMZ) cancer cell lines used in this investigation. The cytotoxic activity of P. austroarabica extract was explored against MCF-7 breast and A549 lung cancer cell lines, along with doxorubicin as a positive control. In both treated cells, P. austroarabica showed a remarkable activity via suppressing the cell’s survival. In terms of IC50 (concentration equivalent to a survival rate of 50%), MCF-7 breast cancer cells were more sensitive to P. austroarabica extract.) DPPH colorimetric assay was employed to assess the antioxidant properties of P. austroarabica extract, the antioxidant activity was increased along with increment of extract concentrations. The leaves aqueous extract of P. austroarabica inhibited the growth of S. aureus by 6.3±0.12 mm and 24±0.43 mm and 15±0.56 mm respectively for seed, leaf and stem at concentrations 50 μl. However, the same concentrations inhibited the growth of E. coli by 25±0.75, 0.00 mm and 24±0.18 mm, following the same order. Different superscript letters indicate means that are significantly different at level (p˂0.05). Minimal inhibitory concentrations (MIC) of P. austroarabica ethanolic extracts against the tested microorganisms were 1.5, 1.6 and 1.5, respectively for seed, leaf and stem against Staph. Aureus and were 1.2, 0.00 and 1.2, respectively for seed, leaf and stem against E. coli.

Bacteriocin production is influenced by various factors such as carbon and nitrogen sources as well as fermentation conditions including pH, temperature, and agitation—these factors aid in optimizing bacteriocin production and improving its inhibitory activity against pathogens for great economic significance. The study investigates the effect of growth conditions on bacteriocin production by Lactobacillus plantarum. The response surface methodology was applied to optimize and determine the interaction among the process variables in bacteriocin production by Lactobacillus plantarum and determine their optimum levels. Chloroform–Methanol (2:1 v/v) was used for crude bacteriocin extraction through the liquid-liquid extraction method, and its antimicrobial activity was assessed. The sample has shown inhibitory activity against all the organism,s i.e., E. coli, S. aureus, K. pneumoniae and P. aeruginosa good diffusion. Compared to control and ciprofloxacin, the sample at all concentrations (Lab 9, 1%, 2%, 3%) has shown better inhibitory activity in pH-7 and-8 at 37 °C against S.aureus in good diffusion. The selected factors were carbon and nitrogen source, temperature, and pH. The bacteriocin was produced at maximum activity in MRS broth supplemented with 1% dextrose and 1% ammonium nitrate. RSM analysis found that the optimal temperature for bacteriocin production was 36°C at a pH of 6.5 using 1% inoculum. At the same time, the increase in the percentage of inoculum (2% and 3%) did not affect bacteriocin production. The quadratic model found that temperature and pH profoundly affected bacteriocin production.

The tomato plant is usually infected with various pathogens such as pests, bacteria, and different mycoflora. In this investigation, Tomato plant cultivar Beeli was pathogenized with Fusarium oxysporum f.sp. Lycopersicon (FOL1) fungi. The FOL1 fungus was controlled by inoculating the pathogenized Tomato plants with each one of the biocontrol microorganisms, such as Arbuscular mycorrhiza (AM), Trichoderma harzianum (T. harzianum), and microbial blend, named as Effective Microorganisms (EM). Consequently, the effect of these biocontrol microorganisms on the amount of chlorophyll, proteins, and defense enzymes of the Tomato plant was estimated. The results showed that the AM, T. harzianum fungi, and “EM” gave similar ameliorative effects. However, there are regulated increasing content of chlorophyll, proteins, and the activities of many protecting compounds such as acid invertase peroxidase. Moreover, these important plant defense mechanisms have a vital role in oxidizing phenolic compounds, which could increase antimicrobial activity. Altogether, the results demonstrate that the protein and chlorophyll are increased differently in all treatments. The protein level is the highest in FOL1 + EM treatment and the ML showed the highest level of chlorophyll.