Strain ATCC Research Articles

Evaluation of the Effects of Heteroaryl Ethylene Molecules in Combination with Antibiotics: A Preliminary Study on Control Strains.

The discovery of compounds with antibacterial activity is crucial in the ongoing battle against antibiotic resistance. We developed two QSAR models to design six novel heteroaryl drug candidates and assessed their antibacterial properties against nine ATCC strains, including Enterococcus faecalis, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and also Salmonella enterica and Escherichia coli, many of which belong to the ESKAPE group. We combined PB4, a previously tested compound from published studies, with GC-VI-70, a newly discovered compound, with the best cytotoxicity/MIC profile. By testing sub-MIC concentrations of PB4 with five antibiotics (linezolid, gentamycin, ampicillin, erythromycin, rifampin, and imipenem), we evaluated the combination's efficacy against the ATCC strains. To assess the compounds' cytotoxicity, we conducted a 24 h and 48 h 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay on colorectal adenocarcinoma (CaCo-2) cells. We tested the antibiotics alone and in combination with PB4. Encouragingly, PB4 reduced the MIC values for GC-VI-70 and for the various clinically used antibiotics. However, it is essential to note that all the compounds studied in this research exhibited cytotoxic activity against cells. These findings highlight the potential of using these compounds in combination with antibiotics to enhance their effectiveness at lower concentrations while minimizing cytotoxic effects.

Uropathogenic bacteria and deductive genomics towards antimicrobial resistance, virulence, and potential drug targets.

Urinary tract infections (UTIs) are among the most prevalent bacterial infections affecting people in inpatient and outpatient settings. The current study aimed to sequence the genome of uropathogenic Escherichia coli strain CUI-B1 resourced from a woman having uncomplicated cystitis and pyelonephritis. Followed by deductive genomics towards potential drug targets using E. coli strain CUI-B1, strain O25b: H4-ST131, Proteus mirabilis strain HI4320, Klebsiella pneumoniae strain 1721, and Staphylococcus saprophyticus strain ATCC 15305 uropathogenic strains. Comparative genome analysis revealed that genes related to the survival of E. coli, P. mirabilis, K. pneumoniae, and S. saprophyticus, such as genes of metal-requiring proteins, defense-associated genes, and genes associated with general physiology, were found to be highly conserved in the genomes including strain CUI-B1. However, the genes responsible for virulence and drug resistance, mainly those that are involved in bacterial secretion, fimbriae, adherence, and colonization, were found in various genomic regions and varied from one species to another or within the same species. Based on the genome sequence, virulence, and antimicrobial-resistant gene dataset, the subtractive proteomics approach revealed 22 proteins mapped to the pathogen's unique pathways and among them, entB, clbH, chuV, and ybtS were supposed to be potential drug targets and the single drug could be utilized for all above-mentioned strains. These results may provide the foundation for the optimal target for future discovery of drugs for E. coli-, P. mirabilis-, K. pneumoniae-, and S. saprophyticus-based infections and could be investigated further to employ in personalized drug development.

Evaluation of the Antibacterial Activity of Gentamicin in Combination with Essential Oils Isolated from Different Cultivars and Morphological Parts of Lavender (Lavandula angustifolia Mill.) against Selected Bacterial Strains.

The aim of the study was to investigate the antibacterial effects of essential oils isolated from different cultivars and morphological parts of lavender (Lavandula angustifolia Mill.) in combination with the aminoglycoside antibiotic gentamicin. This in vitro study analyzed the effectiveness of the combinations of gentamicin and lavender essential oils against the following strains: Staphylococcus aureus ATCC 25923, Staphylococcus aureus MRSA and Pseudomonas aeruginosa ATCC 9027. The effect of the combination of lavender oils with gentamicin was tested using the checkerboard method. A synergistic effect against S. aureus strain ATCC 25923 was found when gentamicin was combined with lavender essential oils isolated from flowers and leafy stalks (flowers: 'Blue River' FICI-0.192; 'Ellagance Purple' FICI-0.288; leafy stalks: 'Blue River' FICI-0.192; 'Ellagance Purple' FICI-0.320). A synergistic effect was also observed for the combination of gentamicin with lavender essential oils from flowers against the resistant strain of S. aureus (MRSA) ('Blue River' FICI-0,191; 'Ellagance Purple' FICI-0.263), as well as for the essential oils from leafy stalks ('Blue River' FICI-0.076; 'Ellagance Purple' FICI-0.089). No interaction was observed for the combination of studied essential oils with gentamicin against P. aeruginosa strain ATCC 9027 (FICI = 1.083-1.300).

EFFECT OF ESSENTIAL OIL FROM Feroniella lucida (SCHEFF.) SWINGLE FRUIT ON Staphylococcus aureus

Staphylococcus aureus is a bacterium commonly found on human skin and mucus membrane linked to the severity of the chronic inflammatory skin disease, and a contaminant in food. This study presented the effect of essential oil extracted from Feroniella lucida (Scheff.) Swingle fruit for its antibacterial activity against two strains of Staphylococcus aureus, ATCC 29213 and TISTR 517; and its chemical composition. The hydro-distillated essential oil yield from the peel was approximately 0.72% (v/w, fresh weight), compared to the average yield of 0.10% (v/w) from the plant leaves. The major components of the peel oil were decyl acetate (56.20% of the total GC-MC peak area), decanal (22.49%), and dodecyl acetate (6.81%). The oil could inhibit both strains, but the ATCC 29213 was more sensitive than TISTR 517 with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 0.125 and 2.0, and 0.5 and 16.0 mg/mL, respectively. For the mode of action performed for the strain ATCC 29213, the essential oil had a significant effect to inhibit the bacterium growth within 2 h, and caused protein, potassium ion, and adenosine triphosphates (ATP) leakages, but it had no effect on the leakage of nucleic acids. Under scanning electron microscope (SEM) observation of the essential oil effect on the bacterial cell morphology, the crease and furrow of ATCC 29213 cells were detected. These results encourage further application of the oil from the edible fruit as anti-Staphylococcus aureus to develop skin care products as well as to be used in food industry.

Acid tolerance of enterohemorrhagic Escherichia coli O157:H7 strain ATCC 43894 and its relationship with a large virulence plasmid pO157

Enterohemorrhagic Escherichia coli (EHEC) O157:H7 is a zoonotic pathogen that causes a severe intestinal infection including hemolytic uremic syndrome in humans. Various factors contribute to its pathogenesis, including a large virulence plasmid pO157. This F-like 92-kb plasmid is isolated in virtually all clinical EHEC isolates, and is considered a hallmark of EHEC virulence. A previous report stated that removal of pO157 from EHEC ATCC 43894 induced overexpression of GadAB that are essential in glutamate-dependent acid resistance (GDAR) system, yet the mechanism remains elusive. Based on this observation, we surmised that pO157 is involved in the regulation of GDAR system. We comparatively analyzed 43894 and its pO157-cured (ΔpO157) mutant 277 for i) their acid resistance, ii) changes in the transcriptional profiles and iii) expression of GDAR associated genes/proteins. Survivability of 43894 upon exposure to acidic conditions was significantly lower than the ΔpO157 mutant. In addition, RNA-sequencing revealed that genes involved in GDAR were significantly down-regulated in 43894 when compared to the ΔpO157 mutant. Exogenous expression of GadE in 43894 led to expression of GadAB, suggesting possible intervention of pO157 in GDAR regulation. Despite these findings, reintroduction of pO157 into 277 did not reverted Gad overexpression. Likewise, removing pO157 from 43894 using the plasmid incompatibility method did not induce Gad overexpression as shown in 277. Taken together, the results suggest that variation in acid resistance among EHEC isolates exists, and the large virulence plasmid pO157 has no effect on weak acid resistance phenotype displayed in 43894.

The Helicobacter pylori single nucleotide polymorphisms SNPs associated with multiple therapy resistance in Colombia.

The eradication of Helicobacter pylori (H. pylori) using multiple therapies is used as a prevention strategy. However, its efficacy has been compromised by the emergence of single nucleotide polymorphisms in genes associated with H. pylori's resistance to multiple antibiotics. To estimate antibiotic resistance rates associated with mutations in H. pylori genes in the high-cancer-risk population in Colombia, we included 166 H. pylori whole genome sequences from a cohort of individuals with a high risk of gastric cancer. By using the reference strain ATCC 26695, we identified mutations in specific genes to evaluate resistance rates for different antibiotics: 23S rRNA for clarithromycin, 16S rRNA for tetracycline, pbp1A for amoxicillin, gyrA for levofloxacin, and rdxA for metronidazole. The phylogenomic analysis was conducted using the core genome consisting of 1,594 genes of H. pylori-ATCC 26695. Our findings revealed that the resistance rate of H. pylori to clarithromycin was 3.62%, primarily associated with mutations A2143G and A2142G in the 23S rRNA gene. For tetracycline, the resistance rate was 7.23%, with mutations A926G, A926T, and A928C observed in the 16S rRNA gene. Amoxicillin resistance was found in 25.9% of cases, with observed mutations in the pbp1A gene, including T556S, T593, R649K, R656P, and R656H. In the gyrA gene, mutations N87K, N87I, D91G, D91N, and D91Y were identified, resulting in a resistance rate of 12.04% to levofloxacin. The most common mutations in the rdxA gene associated with metronidazole resistance were a stop codon, and mutations at D59N and D59S, resulting in a resistance rate of 99.3%. The high resistance rate of H. pylori to metronidazole indicated that this drug should be excluded from the eradication therapy. However, the resistance rates for tetracycline and clarithromycin did not exceed the established resistance threshold in Colombia. The increased resistance rate of H. pylori to levofloxacin and amoxicillin may partially explain the observed therapeutic failures in Colombia. The phylogenomic tree showed that the H. pylori isolate belongs to its own lineage (hspColombia). These findings offer valuable insights to enhance the characterization of treatment protocols for the specific H. pylori lineage (hspColombia) at the local level.

Efficacy of the feed additives consisting of Enterococcus faeciumATCC 53519 and E. faeciumATCC 55593 for all animal species (FEFANA asbl).

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the efficacy of two technological additives consisting of Enterococcus faecium strains ATCC 53519 and ATCC 55593, respectively. The additives are intended for use with all types of fresh materials and for all animal species at a proposed minimum concentration of 1 × 107 colony forming units (CFU) of E.faecium ATCC 53519/kg forage or 5 × 106 CFU of E. faecium ATCC 55593/kg forage. In a previous opinion, the FEEDAP Panel could not conclude on their efficacy since the dry matter content of the ensiled materials at the end of the experiments was not corrected for volatiles, which led to an unreliable estimation of the dry matter loss, and the lack of positive effects on any of the other parameters. The supplementary information submitted by the applicant included updated data on the pH values and the dry matter loss corrected for volatiles. However, the estimation of the dry matter loss corrected for volatiles was wrongly calculated and thus, was not considered for the assessment of the efficacy of the additive. Considering the lack of effect on any other fermentation parameter, the Panel could not conclude on the efficacy of the additive to improve the production of silage under the proposed conditions of use.

A dextrorotatory residues-incorporated bioactive dodecapeptide against enterohemorrhagic Escherichia coli

Aim: This study aims to report an engineered peptide zp39 with favorable bioactivity against enterohemorrhagic Escherichia coli (E. coli, EHEC). Its antibacterial mechanisms and application in a real food system are assessed. Methods: Spatial conformation of synthetic peptide zp39 (GIIAGIIiKIKk-NH2, lowercase letters indicate dextrorotatory amino acids) was predicted by PEPstrMOD and its secondary structure was further determined by circular dichroism (CD) spectroscopy. Then, standard E. coli O157:H7 strain ATCC 43888 was used to evaluate the bioactivity of zp39. A double dilution method was applied to investigate its efficacy in normal broth medium, serum, and highly saline conditions. Its effects on cell membrane permeability and potential were measured by fluorescent assays. Thereafter, morphological changes of E. coli O157:H7 cells were monitored by electron microscopy technologies. Finally, the potential application of zp39 in controlling EHEC in food was tested with spinach juice and the Galleria mellonella larvae model was employed to assess the in vivo efficacy. Results: Peptide zp39 presented an amphiphilic helical structure. It effectively inhibited the growth of E. coli O157:H7 at a concentration of 4 μmol/L in a bactericidal mode. Mechanistic studies revealed that it affected membrane permeability and potential in a dose-dependent manner. Moreover, zp39 maintained satisfactory bioactivity against E. coli O157:H7 even in the presence of 70% serum or 1,000 μmol/L chloride salts. In spinach juice application, > 90% E. coli O157:H7 cells were killed within 2 h after exposure to 64 μmol/L zp39. In vivo study proved that treatment with 64 μmol/L zp39 could effectively boost the survival ratio of infected larvae by 50%. Conclusions: This study depicts a synthetic dodecapeptide that shows the potential application in controlling EHEC. This molecule may be developed into a highly effective antimicrobial agent applied to prevent food contamination and associated infections.

New drug target identification in Vibrio vulnificus by subtractive genome analysis and their inhibitors through molecular docking and molecular dynamics simulations

Vibrio vulnificus is a rod shape, Gram-negative bacterium that causes sepsis (with a greater than 50% mortality rate), necrotizing fasciitis, gastroenteritis, skin, and soft tissue infection, wound infection, peritonitis, meningitis, pneumonia, keratitis, and arthritis. Based on pathogenicity V. vulnificus is categorized into three biotypes. Type 1 and type 3 cause diseases in humans while biotype 2 causes diseases in eel and fish. Due to indiscriminate use of antibiotics V. vulnificus has developed resistance to many antibiotics so curing is dramatically a challenge. V. vulnificus is resistant to cefazolin, streptomycin, tetracycline, aztreonam, tobramycin, cefepime, and gentamycin. Subtractive genome analysis is the most effective method for drug target identification. The method is based on the subtraction of homologous proteins from both pathogen and host. By this process set of proteins present only in the pathogen and perform essential functions in the pathogen can be identified. The entire proteome of Vibrio vulnificus strain ATCC 27562 was reduced step by step to a single protein predicted as the drug target. AlphaFold2 is one of the applications of deep learning algorithms in biomedicine and is correctly considered the game changer in the field of structural biology. Accuracy and speed are the major strength of AlphaFold2. In the PDB database, the crystal structure of the predicted drug target was not present, therefore the Colab notebook was used to predict the 3D structure by the AlphaFold2, and subsequently, the predicted model was validated. Potent inhibitors against the new target were predicted by virtual screening and molecular docking study. The most stable compound ZINC01318774 tightly attaches to the binding pocket of bisphosphoglycerate-independent phosphoglycerate mutase. The time-dependent molecular dynamics simulation revealed compound ZINC01318774 was superior as compared to the standard drug tetracycline in terms of stability. The availability of V. vulnificus strain ATCC 27562 has allowed in silico identification of drug target which will provide a base for the discovery of specific therapeutic targets against Vibrio vulnificus.

In-vitro Comparative Study of the Antimicrobial Efficacy of Combined Nutmeg, Aloe Vera and Neem as an Intracanal Medicament with Calcium Hydroxide on Enterococcus Faecalis

Background: Ideal requirement of an intracanal medicament is that it should have an antibacterial action for the success of endodontic procedures. The "golden standard" intracanal medication is calcium hydroxide, but it still has drawbacks like internal root resorption. The search for an ideal intracanal medication that works well is an ongoing process that is still unsuccessful. In this pilot study, we attempted to search for new materials by drawing motivation from the earlier time. Ayurveda, started in India 3000 years back. Since many herbal products have demonstrated antibacterial, antiseptic, and analgesic properties, there has been renewed interest in them in recent years.
 Aim: To compare in-vitro, the antibacterial efficacy of a combination of herbal extracts i.e nutmeg + aloe vera, nutmeg + neem and nutmeg + distilled water with calcium hydroxide as an intracanal medicament on Enterococcus faecalis.
 Materials and Methods: The ATCC strain 29212 of the bacterium E. faecalis was used in the study. Mueller Hinton agar plate was vaccinated with E. faecalis. The herbal extract mixtures were pipetted into the agar wells on this agar plate, which had four wells with diameters ranging from 8 to 10 millimeters. After using calcium hydroxide as a control, which is the gold standard for intracanal medication, the plate was incubated. The width of the restraint zones around every one of the wells were estimated physically after hatching for 48 hrs.
 Results: The highest zone of inhibition was seen around the wells containing Nutmeg and its combinations. Nutmeg showed better antibacterial efficacy when compared to calcium hydroxide.
 Conclusion: Nutmeg shows promising results for its use as an antibacterial intracanal medicament.

Influence of growth substrate and contaminant mixtures on the degradation of BTEX and MTBE by Rhodococcus rhodochrous ATCC strain 21198.

The degradation of the prevalent environmental contaminants benzene, toluene, ethylbenzene, and xylenes (BTEX) along with a common co-contaminant methyl tert-butyl ether (MTBE) by Rhodococcus rhodochrous ATCC Strain 21198 was investigated. The ability of 21198 to degrade these contaminants individually and in mixtures was evaluated with resting cells grown on isobutane, 1-butanol, and 2-butanol. Growth of 21198 in the presence of BTEX and MTBE was also studied to determine the growth substrate that best supports simultaneous microbial growth and contaminants degradation. Cells grown on isobutane, 1-butanol, and 2-butanol were all capable of degrading the contaminants, with isobutane grown cells exhibiting the most rapid degradation rates and 1-butanol grown cells exhibiting the slowest. However, in conditions where BTEX and MTBE were present during microbial growth, 1-butanol was determined to be an effective substrate for supporting concurrent growth and contaminant degradation. Contaminant degradation was found to be a combination of metabolic and cometabolic processes. Evidence for growth of 21198 on benzene and toluene is presented along with a possible transformation pathway. MTBE was cometabolically transformed to tertiary butyl alcohol, which was also observed to be transformed by 21198. This work demonstrates the possible utility of primary and secondary alcohols to support biodegradation of monoaromatic hydrocarbons and MTBE. Furthermore, the utility of 21198 for bioremediation applications has been expanded to include BTEX and MTBE.

A bivalent outer membrane vesicle-based intranasal vaccine to prevent infection of periodontopathic bacteria

Periodontal disease has become a serious public health problem, not only causing tooth loss, but also inducing chronic disorders of extra-oral organs. The present study assessed an intranasal vaccine strategy to prevent periodontal disease using outer membrane vesicles (OMVs) of two major periodontopathic bacteria, Porphyromonas gingivalis (Pg) and Aggregatibacter actinomycetemcomitans (Aa). We compared the morphology, composition, and immune activity between OMVs of Pg strain ATCC 33277 and Aa strain Y4. Aa OMVs had a smoother surface and stronger lipid A activity compared to Pg OMVs. The in vitro immune activity elicited by Aa OMVs in macrophage-like cells was remarkably stronger than that of Pg OMVs. Intranasal immunization of mice with Aa OMVs alone resulted in robust, humoral immune responses in blood and saliva. Despites the intrinsically low mucosal immunogenicity of Pg OMVs alone, using Aa OMVs as a mucosal adjuvant strongly enhanced Pg-specific immune responses, resulting in both serum IgG and salivary IgA, both of which aggregated Pg and Aa cells. Furthermore, Aa OMVs were found to be a more potent mucosal adjuvant than Poly(I:C) in the context of enhancing the production of Pg-specific IgG (especially IgG2a) and IgA. In addition, in a randomized, blinded study, mice oral challenged with Pg and Aa after intranasal immunization with Pg OMVs and Aa OMVs had significantly decreased numbers of both microorganisms compared to mock-immunized mice. Furthermore, in an intracerebral injection mouse model, there were no serious adverse effects on the brain even after administrating a dose of OMVs as same as that used for intranasal administration. Taken together, the bivalent OMV intranasal vaccine may be effective in preventing colonization of periodontopathic bacteria in the oral cavity and related systemic disorders associated with periodontal diseases.

Replicative Acinetobacter baumannii strains interfere with phagosomal maturation by modulating the vacuolar pH.

Bacterial pneumonia is a common infection of the lower respiratory tract that can afflict patients of all ages. Multidrug-resistant strains of Acinetobacter baumannii are increasingly responsible for causing nosocomial pneumonias, thus posing an urgent threat. Alveolar macrophages play a critical role in overcoming respiratory infections caused by this pathogen. Recently, we and others have shown that new clinical isolates of A. baumannii, but not the common lab strain ATCC 19606 (19606), can persist and replicate in macrophages within spacious vacuoles that we called Acinetobacter Containing Vacuoles (ACV). In this work, we demonstrate that the modern A. baumannii clinical isolate 398, but not the lab strain 19606, can infect alveolar macrophages and produce ACVs in vivo in a murine pneumonia model. Both strains initially interact with the macrophage endocytic pathway, as indicated by EEA1 and LAMP1 markers; however, the fate of these strains diverges at a later stage. While 19606 is eliminated in an autophagy pathway, 398 replicates in ACVs and are not degraded. We show that 398 reverts the natural acidification of the phagosome by secreting large amounts of ammonia, a by-product of amino acid catabolism. We propose that this ability to survive within macrophages may be critical for the persistence of clinical A. baumannii isolates in the lung during a respiratory infection.

Microbiological evaluation in invisible aligner chemical cleaning methods against Candida albicans and Streptococcus mutans

This study aimed to assess the efficacy of chemical agents in removing Candida albicans and Streptococcus mutans biofilm from invisible aligners. The samples were made of EX30 Invisalign trays, biofilm was cultured by standardized suspensions of C. albicans ATCC strain and S. mutans clinical strain on the sample. The treatments used were 0.5% sodium hypochlorite (NaClO) (20 minutes), 1% NaClO (10 minutes), chlorhexidine (5 minutes), peroxide (15 minutes), and orthophosphoric acid (15 seconds). The control group received phosphate-buffered saline for 10 minutes. The colony-forming units per milliliter of each microorganism were determined by serial dilutions seeded in plates with selective culture mediums for each one. Data were analyzed by the Kruskal-Wallis and Conover-Iman tests at an α of 0.05. For the C. albicans biofilm group, the control group had 9.7 Log10 of microorganism growth, and all treatment groups had statistically significant biofilm reduction, in which chlorhexidine presented the highest inhibition of 3 Log10, followed by alkaline peroxide and orthophosphoric acid both with 2.6 Log10, 1% NaClO (2.5 Log10), and 0.5% NaClO (2 Log10). As for S. mutans, the control group had 8.9 Log10 of growth, and a total microorganism inhibition was reached by chlorhexidine, 1% NaClO, and orthophosphoric acid, whereas alkaline peroxide inhibited growth to 7.9 Log10 and 0.5% NaClO 5.1 Log10. Within the limitations, chlorhexidine and orthophosphoric acid had greater efficacy in both biofilms. In addition, 1% NaClO and alkaline peroxide also had significant effects; therefore, their incorporation aligners disinfection protocols are valid.

Novel Synergies and Isolate Specificities in the Drug Interaction Landscape of Mycobacterium abscessus.

Mycobacterium abscessus infections are difficult to treat and are often considered untreatable without tissue resection. Due to the intrinsic drug-resistant nature of the bacteria, combination therapy of three or more antibiotics is recommended. A major challenge in treating M. abscessus infections is the absence of a universal combination therapy with satisfying clinical success rates, leaving clinicians to treat infections using antibiotics lacking efficacy data. We systematically measured drug combinations in M. abscessus to establish a resource of drug interaction data and identify patterns of synergy to help design optimized combination therapies. We measured 191 pairwise drug combination effects among 22 antibacterials and identified 71 synergistic pairs, 54 antagonistic pairs, and 66 potentiator-antibiotic pairs. We found that commonly used drug combinations in the clinic, such as azithromycin and amikacin, are antagonistic in the lab reference strain ATCC 19977, whereas novel combinations, such as azithromycin and rifampicin, are synergistic. Another challenge in developing universally effective multidrug therapies for M. abscessus is the significant variation in drug response between isolates. We measured drug interactions in a focused set of 36 drug pairs across a small panel of clinical isolates with rough and smooth morphotypes. We observed strain-dependent drug interactions that cannot be predicted from single-drug susceptibility profiles or known drug mechanisms of action. Our study demonstrates the immense potential to identify synergistic drug combinations in the vast drug combination space and emphasizes the importance of strain-specific combination measurements for designing improved therapeutic interventions.

Biocidal activity of multifunctional cuprite-doped anion exchanger – Influence of bacteria type and medium composition

The study presents unconventional, bifunctional, heterogeneous antimicrobial agents – Cu2O-loaded anion exchangers. The synergetic effect of a cuprous oxide deposit and polymeric support with trimethyl ammonium groups was studied against the reference strains of Enterococcus faecalis ATCC 29212 and Pseudomonas aeruginosa ATCC 27853. Biological testing (minimum bactericidal concentration, MBC), time- and dose-dependent bactericidal effect (under different conditions – medium composition and static/dynamic culture) demonstrated promising antimicrobial activity and confirmed its multimode character. The standard values of MBC, for all studied hybrid polymers and bacteria, were similar (64–128 mg/mL). However, depending on the medium conditions, due to the copper release into the bulk solution, bacteria were actively killed even at much lower doses of the hybrid polymer (25 mg/mL) and low Cu(II) concentrations in solution (0.01 mg/L). Simultaneously, confocal microscopic studies confirmed the effective inhibition of bacterial adhesion and biofilm formation on their surface. The studies conducted under different conditions showed also the influence of the structure and physical properties of studied materials on the biocidal efficacy and an antimicrobial action mechanism was proposed that could be significantly affected by electrostatic interactions and copper release to the solution. Although the antibacterial activity was also dependent on various strategies of bacterial cell resistance to heavy metals present in the aqueous medium, the studied hybrid polymers are versatile and efficient biocidal agents against bacteria of both types, Gram-positive and Gram-negative. Therefore, they can be a convenient alternative for point-of-use water disinfection systems providing water quality in medical devices such as dental units, spa equipment, and aesthetic devices used in the cosmetic sector.

Safety and efficacy of a feed additive consisting of monensin sodium (Elancoban® G200) for chickens for fattening, chickens reared for laying and turkeys (ElancoGmbH).

Following a request from the European Commission, EFSA was asked to deliver a new scientific opinion on the coccidiostat monensin sodium (Elancoban® G200) when used as a feed additive for chickens for fattening and turkeys. Based on the new data provided, the Panel updates its previous conclusions as follows: monensin sodium is produced by fermentation by a non-genetically modified strain of Streptomyces sp. NRRL B-67924. Genome analysis suggests the production strain may belong to a new species within the genus Streptomyces. The production strain and its DNA were not detected in the final additive. The product is free of antimicrobial activity other than monensin. The FEEDAP Panel cannot conclude on the safety of monensin sodium from Elancoban® G200 in feed for chickens for fattening and chickens reared for laying at the proposed maximum use level due to a dose-related reduction of the final body weight. The toxicological profile of monensin sodium was evaluated in studies made with the product obtained from the parental strain ATCC 15413. Based on a comparison of the genomes of the two strains, the FEEDAP Panel concludes that toxicological equivalence has been established, thus the conclusions already drawn on Elancoban® G200 are valid for the product obtained with the new production strain concluding that the additive is safe for the consumer and the environment; the production strain does not represent an additional risk when safety for the user is considered. Monensin sodium from Elancoban® G200 is safe for turkeys up to 16 weeks of age at the concentration of 100 mg monensin sodium/kg feed and has the potential to control coccidiosis at the minimum concentration of 60 mg/kg complete feed.

Phytochemical Characterisation, Antioxidant and Antidiabetic activity of extracts of Neptunia prostrata Linn.

The herb Neptunia prostrata Linn. Is belonging to the family Mimosaceae have been used in folkloric medicine in the North-eastern states of Indiaof Assam and Tripura by indigenous herbal healers since time immemorial but there is a scarcity of any background study documenting its use as an antimicrobial herb. For the same, plants were collected and authenticated. Following identification of these herbs methanolic, ethanolic, pet ether and chloroform extracts were prepared using soxhletion. Acute toxicity study as per OECD guidelines 420 was assessed in wistar albino rats and in swiss albino mice (n=5) of both sexes at doses of 2000mg/kg body weight and did not reveal any morbidity or mortality in the animals within the stipulated period.Phytochemical screening was performed on all four extracts of Neptunia prostrata. Phytochemical constituents depicted presence of glycoside, flavonoids in only ethanolic, methanolic and chloroform extracts. Alkaloids were present in the chloroform extract. The antimicrobial activity was performed by disc agar diffusion method with respect to amoxicillin at standard doses against ATCC strains of Gram positive Staphylococcus aureus, Bacillus subtilis and Gram negative Salmonella typhi. The herbs showed antioxidant activity comparable to standard antioxidants in-vitro such as Ascorbic acid (Vitamin C) with comparable IC 50 values. Results of the antibacterial assay on the basis of zone of inhibition (mm) and MIC values of extracts of the extract (NPHE) under study to suggest these two indigenous herb have conspicuous and potent putative role in the therapeutics of a vast plethora bacterial infections that need to be corroborated for the expansion of future prospective in-vivo studies with larger sample size.

Structural and binding studies of a new chitin-active AA10 lytic polysaccharide monooxygenase from the marine bacterium Vibrio campbellii.

Vibrio spp. play a crucial role in the global recycling of the highly abundant recalcitrant biopolymer chitin in marine ecosystems through their ability to secrete chitin-degrading enzymes to efficiently hydrolyse chitinous materials and use them as their major carbon source. In this study, the first crystal structures of a complete four-domain chitin-active AA10 lytic polysaccharide monooxygenase from the chitinolytic bacterium Vibrio campbellii type strain ATCC BAA-1116 are reported. The crystal structures of apo and copper-bound VhLPMO10A were resolved as homodimers with four distinct domains: an N-terminal AA10 catalytic (CatD) domain connected to a GlcNAc-binding (GbpA_2) domain, followed by a module X domain and a C-terminal carbohydrate-binding module (CBM73). Size-exclusion chromatography and small-angle X-ray scattering analysis confirmed that VhLPMO10A exists as a monomer in solution. The active site of VhLPMO10A is located on the surface of the CatD domain, with three conserved residues (His1, His98 and Phe170) forming the copper(II)-binding site. Metal-binding studies using synchrotron X-ray absorption spectroscopy and X-ray fluorescence, together with electron paramagnetic resonance spectroscopy, gave consistently strong copper(II) signals in the protein samples, confirming that VhLPMO10A is a copper-dependent enzyme. ITC binding data showed that VhLPMO10A could bind various divalent cations but bound most strongly to copper(II) ions, with a Kd of 0.1 ± 0.01 µM. In contrast, a Kd of 1.9 nM was estimated for copper(I) ions from redox-potential measurements. The presence of ascorbic acid is essential for H2O2 production in the reaction catalysed by VhLPMO10A. MALDI-TOF MS identified VhLPMO10A as a C1-specific LPMO, generating oxidized chitooligosaccharide products with different degrees of polymerization (DP2ox-DP8ox). This new member of the chitin-active AA10 LPMOs could serve as a powerful biocatalyst in biofuel production from chitin biomass.

Biodegradation of atrazine using selected marine bacteria: Possibilities for treating pesticide - contaminated wastewater

The use of pesticides including atrazine can cause detrimental problems to the environment. Atrazine, 2-chloro-4-(ethylamine)-6- (isopropyl amine)-s-triazine, is one of the widely used herbicides. In this work, thirteen pure bacterial strains were isolated from water and sediments collected from different sites along Alexandria Mediterranean Coast and were evaluated for their efficacy to biodegrade atrazine at three elevated concentrations (I: 109, II: 299 &III: 438 mg/L) for 7 days. Atrazine residues were determined using gas chromatography (GC). Marine isolates exhibited very high atrazine biodegradation with removal efficacy ranging between 15.79 and 75.49, 77.97–97.13 and 27.4–87.6% at three elevated concentrations, respectively. The results indicated that 5 of the isolates (E7, 8, 9, 11 and 13) were the most efficient, and active as atrazine bio-degraders. They were affiliated as Bacillus pacificus strain MCCC 1A06182 (E7 and E8), Bacillus cereus strain ATCC 14579 (E9) and Bacillus paramycoides strain MCCC 1A04098 (E11 and E13). Results obtained provided evidence that marine environment is a natural, rich and renewable source of bacteria with marvelous metabolic capabilities for efficient bioremediation of atrazine-contaminated aquatic environments or wastewater.