Syzygium aromaticum Extracts as a Potential Antibacterial Inhibitors against Clinical Isolates of Acinetobacter baumannii: An In-Silico-Supported In-Vitro Study.

Imipenem is the most efficient antibiotic against Acinetobacter baumannii infection, but new research has shown that the organism has also developed resistance to this agent. A. baumannii isolates from a total of 110 clinical samples were identified by multiplex PCR. The antibacterial activity of Syzygium aromaticum multiple extracts was assessed following the GC-Mass spectra analysis. The molecular docking study was performed to investigate the binding mode of interactions of guanosine (Ethanolic extract compound) against Penicillin- binding proteins 1 and 3 of A. baumannii. Ten isolates of A. baumannii were confirmed to carry recA and iutA genes. Isolates were multidrug-resistant containing blaTEM and BlaSHV. The concentrations (0.04 to 0.125 mg mL-1) of S. aromaticum ethanolic extract were very promising against A. baumannii isolates. Even though imipenem (0.02 mg mL-1) individually showed a great bactericidal efficacy against all isolates, the in-silico study of guanosine, apioline, eugenol, and elemicin showed acceptable fitting to the binding site of the A. baumannii PBP1 and/or PBP3 with highest binding energy for guanosine between -7.1 and -8.1 kcal/mol respectively. Moreover, it formed π-stacked interactions with the residue ARG76 at 4.14 and 5.6, Å respectively. These findings might support the in vitro study and show a substantial increase in binding affinity and enhanced physicochemical characteristics compared to imipenem.

Efficacy of Ethanolic Extract of Syzygium aromaticum in the Treatment of Multidrug-Resistant Pseudomonas aeruginosa Clinical Isolates Associated with Urinary Tract Infections.

Pseudomonas aeruginosa is an organism commonly found in the environment and one of the most common causes of human urinary tract infections in developed and developing countries. The present study aimed to investigate the effect of five medicinal plant extracts on the isolated drug-resistant P. aeruginosa clinical isolates. A total of 100 urine samples were collected from Nagaa Hammadi and Qena General Hospitals and private medical analysis laboratories in Qena governorate, Upper Egypt. Samples were screened for the prevalence of UTI pathogens by biochemical tests, antibiotics sensitivity, detection of virulence, and antibiotic-resistant genes by using multiplex PCR. P. aeruginosa is by far the subdominant causative agent with a percentage of 14%. Clinical isolates were multidrug-resistant, containing bla TEM, bla SHV, toxA, lasB, pslA, and fliC resistant and virulence genes. Based on bioactivity, the ethanolic extract of clove (Syzygium aromaticum) was the most active extract among tested medicinal plants and had the maximum zone of inhibition sized 23 mm against tested bacteria. The results of the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) showed a high decrease of inhibition within a concentration range of (10 to 121.25 mg/mL and 20 to 30 mg/mL, respectively). Further, major compounds of oleic acid (27.22%), guanosine (8.91%), indole (6.83%), 1-eicosene (6.30%), and cis-10-nonadecenoic acid (5.37%) were determined among 12 bioactive compounds in the ethanolic extract of S. aromaticum using gas chromatography-mass spectrometry (GC-MS). These results indicated that the ethanolic extract of S. aromaticum is a promising antibacterial agent for further studies aiming to control bacterial infections including MDR bacteria and develop novel therapeutic alternatives for the treatment of UTI.

Mitigation of Copper Stress in Maize by Inoculation with Paenibacillus polymyxa and Bacillus circulans.

Copper (Cu) is a micronutrient that assumes a principal role in plant growth and development. However, its excess concentration in soil is imperiling crop productivity. Inoculation with different bacterial strains in cereals could modify growth traits, photosynthetic effectiveness, and generation of strong antioxidant defense systems to make them more tolerant of Cu stress. Therefore, a pot study was designed to test plant growth-promoting rhizobacteria (PGPR) including Paenibacillus polymyxa and Bacillus circulans to Cu exposed maize (Zea mays L.) plants. Increasing Cu (100 to 500 µM of CuSO4) concentration decreased growth traits, photosynthetic pigments, soluble sugars, phosphorous (P) and potassium (K) contents, and the activity of catalase (CAT) but increased proline and malondialdehyde (MDA) content, the activity of peroxidase (POD) and Cu ions at root and shoot level. Moreover, the bacterial treatment also modulated the antioxidant capability in stress-free plants. Nevertheless, inoculation with P. polymyxa and B. circulans alleviated Cu-induced growth, photosynthetic pigments and mineral nutrient (P and K) on one hand and regulating the pools of osmolytes and antioxidant enzymes, whilst simultaneously reducing MDA and Cu root and shoot contents. These improved activities of antioxidant enzymes and the regulation of osmolytes content elicited by the blend of bacterial inoculation would have retained the ability of maize plants to confer resilience to Cu stress. This study further affirms that the application of two specific bacterial strains to maize plants proved very effective to ameliorate the Cu toxicity.

Optimizing and purifying extracellular amylase from soil bacteria to inhibit clinical biofilm-forming bacteria.

BACKGROUND: Bacterial biofilms have become a major threat to human health. The objective of this study was to isolate amylase-producing bacteria from soil to determine the overall inhibition of certain pathogenic bacterial biofilms. METHODS: We used serial dilution and the streaking method to obtain a total of 75 positive amylase isolates. The starch-agar plate method was used to screen the amylolytic activities of these isolates, and we used morphological and biochemical methods to characterize the isolates. Optimal conditions for amylase production and purification using Sephadex G-200 and SDS-PAGE were monitored. We screened these isolates' antagonistic activities and the purified amylase against pathogenic and multi-drug-resistant human bacteria using the agar disk diffusion method. Some standard antibiotics were controlled according to their degree of sensitivity. Finally, we used spectrophotometric methods to screen the antibiofilm 24 and 48 h after application of filtering and purifying enzymes in order to determine its efficacy at human pathogenic bacteria. RESULTS: The isolated Bacillus species were Bacillus megaterium (26.7%), Bacillus subtilis (16%), Bacillus cereus (13.3%), Bacillus thuringiesis (10.7%), Bacillus lentus (10.7%), Bacillus mycoides (5.3%), Bacillus alvei (5.3%), Bacillus polymyxa (4%), Bacillus circulans (4%), and Micrococcus roseus (4%). Interestingly, all isolates showed a high antagonism to target pathogens. B. alevi had the highest recorded activity (48 mm) and B. polymyxa had the lowest recorded activity (12 mm) against Staphylococcus aureus (MRSA) and Escherichia coli, respectively. On the other hand, we detected no antibacterial activity for purified amylase. The supernatant of the isolated amylase-producing bacteria and its purified amylase showed significant inhibition for biofilm: 93.7% and 78.8%, respectively. This suggests that supernatant and purified amylase may be effective for clinical and environmental biofilm control. DISCUSSION: Our results showed that soil bacterial isolates such as Bacillus sp. supernatant and its purified amylase are good antibiofilm tools that can inhibit multidrug-resistant former strains. They could be beneficial for pharmaceutical use. While purified amylase was effective as an antibiofilm, the isolated supernatant showed better results.

Efficacy of Acacia nilotica aqueous extract in treating biofilm-forming and multidrug resistant uropathogens isolated from patients with UTI syndrome.

Escherichia coli is the dominant bacterial cause of UTI among the uropathogens in both developed and developing countries. This study is to investigate the effect of Acacia nilotica aqueous extract on the survival and biofilm of isolated pathogens to reduce UTIs diseases. A total of 170 urine samples were collected from Luxor general hospital and private medical analysis laboratories in Luxor providence, Egypt. Samples were screened for the incidence of uropathogens by biochemical tests, antibiotics susceptibility, detection of virulence, and antibiotic-resistant genes by multiplex PCR, biofilm formation, and time-killing assay. Escherichia coli is by far the most prevalent causative agent with the percentage of 73.7% followed by Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeuroginosa, and Acinetobacter baumanii. Isolates were multidrug-resistant containing blaTEM, blaSHV, blaCTX, qnrs, and aac(3)-Ia resistant genes. All isolates were sensitive to 15-16.7 mg ml-1 of Acacia nilotica aqueous extract. Time killing assay confirmed the bactericidal effect of the extract over time (20-24 h). A high percentage of 3-Cyclohexane-1-Carboxaldehyde, 2,6,6-trimethyl (23.5%); á-Selinene (15.12%); Oleic Acid (14.52%); Globulol (11.35%) were detected among 19 bioactive phytochemical compounds in the aqueous extract of A. nilotica over the GC-mass spectra analysis. The plant extract reduced significantly the biofilm activity of E. coli, K. pneumoniae, P. mirabilis, and P. aeuroginosa by 62.6, 59. 03, 48.9 and 39.2%, respectively. The challenge to improve the production of A. nilotica phytochemicals is considered a very low price for the return.

Synthesis, Characterization, Antibacterial Activity, and Computer-Aided Design of Novel Quinazolin-2,4-dione Derivatives as Potential Inhibitors Against Vibrio cholerae.

Cholera is a bacterial disease featured by dehydration and severe diarrhea. It is mainly caused by alimentary infection with Vibrio cholerae. Due to the wide applicability of quinazolin-2,4-dione compounds in medicinal and pharmaceutical chemistry, a new series of N-containing heterocyclic compounds was synthesized. We used the in silico docking method to test the efficacy of quinazolin-2,4-dione compounds in the prevention of cholera in humans. The newly synthesized compounds showed strong interactions and good binding affinity to outer membrane protein OmpU. Moreover, the pharmacokinetic properties of the newly synthesized compounds, such as absorption, distribution, metabolic, excretion, and toxicity (ADMET), were predicted through in silico methods. Compounds with acceptable pharmacokinetic properties were tested as novel ligand molecules. The synthesized compounds were evaluated in vitro for their antibacterial activity properties against Gram-negative Escherichia coli O78 strain using the minimum inhibition concentration (MIC) method. Compounds 2 and 6 showed reproducible, effective antibacterial activity. Hence, our study concludes that the quinazolin-2,4-dione derivatives 1 to 8 may be used as promising drug candidates with potential value for the treatment of cholera disease.

Synbiotic as eco-friendly feed additive in diets of chickens under hot climatic conditions.

This study was conducted to investigate the effect of synbiotic supplementation on performance, survivability rate, microbial populations, ammonia production, liver function, and meat physicochemical properties as well as carcass characteristics in broiler chicks under hot climatic conditions. A total of 320 one-day-old Ross 308 broiler chicks were randomly assigned to 4 dietary treatments as follows: control diet without synbiotic (S0), synbiotic at 500 mg/kg for starter diet and 250 mg/kg grower diet (S1), synbiotic at 1000 mg/kg for starter diet and 500 mg/kg grower diet (S2), and synbiotic at 1500 mg/kg for starter diet and 750 mg/kg grower diet (S3). Each treatment had 10 replicate pens with 8 birds. Diets were formulated using corn, sorghum, soybean meal, corn gluten meal and sunflower oil as major ingredients to meet the nutrient requirements for starter (1 to 21 d) and grower (22 to 35 d) periods. The experiment lasted for 35 d. The results showed that body weight and body weight gain were increased (linear, P<0.01) with the increase in dietary synbiotic feeding during the trial period. In addition, the feed intake linearly increased (P < 0.001) with increasing synbiotic levels and, in turn, caused linear improvements (P < 0.001) in feed conversion values. Interestingly, E. coli, Salmonella and Shigella were decreased (P < 0.001) by supplemental synbiotic levels compared to the control group during the entire study. Furthermore, there was beneficial effects on excreta ammonia reduction (P < 0.001) by supplementation of synbiotic groups compared to control. Increasing synbiotic levels decreased (P < 0.001) drip loss and cook loss percentage of breast and leg muscles without any significant changes in pH values. Dressing, breast, and leg percentages were increased, and abdominal fat percentage was decreased by supplemental synbiotic levels. In conclusion, this investigation demonstrated that synbiotic can be used as an effective feed additive to improve productive performance, meat quality, and ammonia reduction as well as decrease microbial populations of broiler chicks in hot climatic regions.

Selective oxidation of trimethylolpropane to 2,2-bis(hydroxymethyl)butyric acid using growing cells of Corynebacterium sp. ATCC 21245.

Multifunctional chemicals including hydroxycarboxylic acids are gaining increasing interest due to their growing applications in the polymer industry. One approach for their production is a biological selective oxidation of polyols, which is difficult to achieve by conventional chemical catalysis. In the present study, trimethylolpropane (TMP), a trihydric alcohol, was subjected to selective oxidation using growing cells of Corynebacterium sp. ATCC 21245 as a biocatalyst and yielding the dihydroxy-monocarboxylic acid, 2,2-bis(hydroxymethyl)butyric acid (BHMB). The study revealed that co-substrates are crucial for this reaction. Among the different evaluated co-substrates, a mixture of glucose, xylose and acetate at a ratio of 5:5:2 was found optimum. The optimal conditions for biotransformation were pH 8, 1v/v/m airflow and 500rpm stirring speed. In batch mode of operation, 70.6% of 5g/l TMP was converted to BHMB in 10 days. For recovery of the product the adsorption pattern of BHMB to the anion exchange resin, Ambersep(®) 900 (OH(-)), was investigated in batch and column experiments giving maximum static and dynamic binding capacities of 135 and 144mg/g resin, respectively. BHMB was separated with 89.7% of recovery yield from the fermentation broth. The approach is applicable for selective oxidation of other highly branched polyols by biotransformation.

Efficacy of Caltropis procera and Ficus sycomorus extracts in treating MRSA (methicillin-resistant Staphylococcus aureus)-keratitis in rabbit.

MRSA-induced keratitis in rabbit was used to evaluate the therapeutic effect of F. sycomorus leaves and C. procera latex extracts. Within the 6 rabbit groups tested, group 1 received sterilized saline, while other groups (2 to 6) received 100 µl of intrastromal injections of 1.5×10(3) colony forming unit (cfu) ml(-1) of methicillin-resistant Staphylococcus aureus (MRSA). After 12 hours, groups 3 to 6 also received chloramphenicol, aqueous extract of C. procera latex, aqueous and alcoholic extracts of F. sycomorus leaves, respectively 3 times daily for 12 successive days. The tested extracts inhibited MRSA growth in vitro (i.e. on culture medium). Colony counts in cornea discs from groups 3 to 6 were significantly reduced (P ≤ 0.001) compared to group 2 (untreated). Clinical signs of keratitis were observed on group 2 until the end of experiment. In groups 3 to 6, gradual recovery was observed and signs disappeared by the 12(th) DPI (days post inoculation). Only mild symptoms persisted in group 5 (aqueous extract of leaves). In group 3 and 5, cornea, iris, ciliary body and conjunctiva showed mild leukocytic infiltration and depigmentation of melanin cells while recovery of cornea and iris was observed in groups 4 and 6. In conclusion, the used extracts have potential therapeutic effects on MRSA-induced keratitis in rabbit.

Antibacterial activity of silver and zinc nanoparticles against Vibrio cholerae and enterotoxic Escherichia coli.

Vibrio cholerae and enterotoxic Escherichia coli (ETEC) remain two dominant bacterial causes of severe secretory diarrhea and still a significant cause of death, especially in developing countries. In order to investigate new effective and inexpensive therapeutic approaches, we analyzed nanoparticles synthesized by a green approach using corresponding salt (silver or zinc nitrate) with aqueous extract of Caltropis procera fruit or leaves. We characterized the quantity and quality of nanoparticles by UV-visible wavelength scans and nanoparticle tracking analysis. Nanoparticles could be synthesized in reproducible yields of approximately 10(8) particles/ml with mode particles sizes of approx. 90-100 nm. Antibacterial activity against two pathogens was assessed by minimal inhibitory concentration assays and survival curves. Both pathogens exhibited similar resistance profiles with minimal inhibitory concentrations ranging between 5×10(5) and 10(7) particles/ml. Interestingly, zinc nanoparticles showed a slightly higher efficacy, but sublethal concentrations caused adverse effects and resulted in increased biofilm formation of V. cholerae. Using the expression levels of the outer membrane porin OmpT as an indicator for cAMP levels, our results suggest that zinc nanoparticles inhibit adenylyl cyclase activity. This consequently deceases the levels of this second messenger, which is a known inhibitor of biofilm formation. Finally, we demonstrated that a single oral administration of silver nanoparticles to infant mice colonized with V. cholerae or ETEC significantly reduces the colonization rates of the pathogens by 75- or 100-fold, respectively.