Tested Bacteria Strains Research Articles

Bacterial adhesion rate on food grade ceramics and Teflon as kitchen worktop surfaces

Here we present a research of bacterial adhesion to two most often used materials in modern kitchens, namely food grade ceramics and Teflon. To test the bacterial adhesion on kitchen worktops Escherichia coli, Pseudomonas aeruginosa and Campylobacter jejuni were used as the most common foodborne contaminants. Contact angle, roughness and streaming potential measurements were used for surface characterization. Crystal violet staining and scanning electron microscopy were applied for bacterial adhesion analysis. We showed that the adhesion of tested bacteria strains was lower on the Teflon surface compared to the ceramics. The hydrophobicity of the surface substantially contributed to the bacterial adhesion rate. On the other hand, the surface roughness and charge did not play a crucial role in the adhesion process.

Biogenic nano silver: Synthesis, characterization, antibacterial, antibiofilms, and enzymatic activity

Powder technology covers many fields from medicine to material science. Especially easy synthesis of nano- and micro-sized particles and low-cost synthesis with non-toxic chemicals are essential. The ability to design nanoparticles according to the application area and desired features is an advantage for many applications. Nanoparticles biosynthesis is under research due to broad biomedical practise. To synthesize of silver nanoparticle from the plant extract, Corylus avellana (Hazelnut) leaves were utilized for bioreduction of silver nitrate. The plant extract is thoroughly mixed with silver nitrate solution, studied the synthesis of nanoparticles using UV–Vis spectroscopy. The nanoparticles were characterized by SEM and XRD-Pattern. XRD analysis proved that the size range of the nanoparticles was 32 nm. Scanning microscope images also demonstrate nanoparticles having spherical shape and a mean size between 9 nm and 50 nm. The antibacterial effect of AgNPs obtained from hazelnut leaves demonstrated antibacterial effect against all tested bacteria strains. The results demonstrated that the plant extract acts as a good bioreductant for the production of silver nanoparticles. This compound was good inhibitor of the α-glycosidase, human carbonic anhydrase I and II isoforms, and cholinesterase enzymes. The results were obtained with Ki values of 12.84 ± 0.41 µM for α-glycosidase, 27.94 ± 3.77 µM for hCA I, 36.12 ± 6.03 µM for hCA II, 47.05 ± 6.83 µM for BChE, and 53.94 ± 7.55 µM for AChE, respectively.

Design and biological evaluation of a novel type of potential multi-targeting antimicrobial sulfanilamide hybrids in combination of pyrimidine and azoles

This work explored a novel type of potential multi-targeting antimicrobial three-component sulfanilamide hybrids in combination of pyrimidine and azoles. The hybridized target molecules were characterized by 1H NMR, 13C NMR and HRMS spectra. Some of the developed target compounds exerted promising antimicrobial activity in comparison with the reference drugs norfloxacin and fluconazole. Noticeably, sulfanilamide hybrid 5c with pyrimidine and indole could effectively inhibit the growth of E. faecalis with MIC value of 1 μg/mL. The active molecule 5c showed low cell toxicity and did not obviously trigger the development of resistance towards the tested bacteria strains. Mechanism exploration indicated that compound 5c could not only exert efficient membrane permeability, but also intercalate into DNA of resistant E. faecalis to form 5c-DNA supramolecular complex, which might be responsible for its antimicrobial action. The further investigation showed that this molecule could be effectively transported by human serum albumins through hydrogen bonds and van der Waals force.

Antistaphylococcal Activity of Extracts, Fractions, and Compounds of Acacia polyacantha Wild (Fabaceae)

Acacia polyacantha is a medicinal plant traditionally used to treat livestock diseases and gastrointestinal infections; our study was undertaken to evaluate the antistaphylococcal activities of the methanolic leaf, bark, and root extracts, fractions, and compounds from Acacia polyacantha against a panel of 14 multidrug-resistant Staphylococcus bacterial strains overexpressing efflux pumps. The study was also extended to investigate two possible modes of action, that is, influence on bacterial growth kinetics and influence on proton-ATPase pumps, of the most active compound against a reference strain. Materials and Methods. The crude extracts after extraction were subjected to column chromatography. Antibacterial assays of extracts, fractions, and compounds alone and in the presence of efflux pump inhibitors were carried out using the broth microdilution method and the study of two mechanisms of action achieved by standard methods with the most active compound. Results. The phytochemical study of Acacia polyacantha leaves leads to the isolation of stigmasterol (1), β-amyrin (2), 3-O-methyl-D-chiro-inositol (3), epicatechin (4), quercetin-3-O-galactoside (5), 3-O-[β-D-xylopyranosyl-(1 ⟶ 4)-β-D-galactopyranosyl]-oleanolic acid (6), 3-O-[β-galactopyranosyl-(1⟶ 4)-β-D-galactopyranosyl]-oleanolic acid (7) and that of leaves lead to the isolation of lupeol (8) 2,3-dihydroxypropyltetracosanoate (9), and methyl-gallate (10). Leaf, root, and bark extracts inhibited 92.85% (13/14), 92.85% (13/14), and 71.43 % (10/14) of the tested bacteria strains, respectively, with minimum inhibitory concentration (MIC) varying between 16 and 1024 μg/mL. Fractions exhibited better activities compared to those of their extracts of origin, as their MICs ranged from 16 to 512 μg/mL, with fractions from leaves being more active than those obtained from barks. Compounds had varying activities; MICs varied from 16 to 512 μg/mL with compound 4 presenting the best activity as MICs ≤100 μg/mL were obtained against 11 of the tested bacteria. The activities of extracts, fractions, and compounds were improved in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) as an efflux pump inhibitor to as much as >128 folds. Meanwhile, in the presence of chlorpromazine as an efflux pump inhibitor, only the activity of compound 10 was improved on 10 of the tested bacteria strains. Compound 4 prolonged the lag phase of the growth kinetic in a concentration-dependent manner and equally inhibited the proton-ATPase pumps of the tested bacteria strains. Conclusion. The present study demonstrates the antistaphylococcal potential of Acacia polyacantha and its constituents to combat bacterial infections alone or in combination with efflux pump inhibitors.

Variations of the antimicrobial, antioxidant, sensory attributes and biogenic amines content in Lithuania-derived bee products

This study examined the antimicrobial and antioxidant properties, overall acceptability (OA), including influence of the product-induced emotions, and biogenic amine (BA) content in fourteen honey (H1–14), four propolis (P15–18) and four bee bread (BB19–22) samples, collected in northwest Lithuania. The all tested bacteria were inhibited by summer honey H13. P18 inhibited 10, while bee breads inhibited 10–11 out of the 15 tested bacteria strains. All propolis-samples inhibited B.cereus and P.multocida. The highest antioxidant activity and content of total phenolic compounds (TPC) were found in bee bread (93% and 394 mg GAE/100 g, respectively). The TPC had moderate and strong negative correlations with the L* (r = −0.58) and b* colour coordinates (r = −0.66), respectively. The each bee products group (BPs) induced different intensities of emotions, and the OA showed a moderate positive correlation with the “neutral” emotion (r = 0.47). A low content of BAs (<15 mg/kg) was identified in six honeys, two bee breads and one propolis sample. In sum, Lithuanian bee products possessed valuable biological attributes that can be beneficially used in food industry and medicine, although further research is needed for the factors, which may contribute to bioactive properties of this region bee products and BAs formation.

In vitro evaluation of the decontamination effect of cold atmospheric argon plasma on selected bacteria frequently encountered in small animal bite injuries

Beneficial effects of cold atmospheric argon plasma (CAAP) on wound healing and its capacity for bacterial decontamination has recently been documented. First, in vivo studies in small animals did not prove any decontamination effect in canine bite wounds. The present study evaluated the overall decontamination effect of CAAP for different bacteria frequently encountered in canine bite wounds with respect to growth phase, initial bacteria concentration and treatment duration.Standard strains of Escherichia (E.) coli, Staphylococcus (S.) pseudintermedius, S. aureus, Streptococcus (S.) canis, Pseudomonas (P.) aeruginosa and Pasteurella multocida were investigated. To evaluate the influence of the bacterial growth phase, each bacterium was incubated for three and eight hours, before CAAP treatment. Three different bacterial concentrations were created per bacterium and growth phase, and were exposed to CAAP for 30 s, 1 min and 2 min.CAAP treatment resulted in acceptable decontamination rates (range 98.9–99.9%) in all bacteria species in vitro; however, differences in susceptibility were detected. Decontamination rate was mainly influenced by initial bacterial concentration and treatment time. Growth phase only influenced decontamination in S. pseudintermedius. Treatment time significantly (P < .05) correlated with the decontamination rate in E. coli, S. canis and S. aureus, with an exposure time of 2 min being most effective. Initial bacterial concentration significantly (P < .05) influenced decontamination in Pasteurella multocida and P. aeruginosa, in which treatment time was not as important. CAAP exerts effective antibacterial activity against the tested bacteria strains in vitro, with species specific effects of treatment time, growth phase and concentration.

Chemical characterization, antioxidant and antimutagenic evaluations of pigmented corn.

In order to identify pigmented corn with nutraceutical potential, the secondary metabolite content, the antioxidant capacity and antimutagenic activity of red, and blue corn were analyzed. The ranges of total phenolic, flavonoid and anthocyanin contents of the corn samples were from 69.4 to 212.8mg gallic ac. equiv./100g DW, 0.07 to 12.19mg (+) catechin eq./100g DW and 3.89 to 34.17mg cyanidin-3-O-glucoside eq./100g DW, respectively. The phenolic extracts demonstrated the highest antioxidant capacity evaluated by the ABTS assay displaying values from 2.06 to 7.34mmol Trolox/100g DW. None of the extracts was toxic to the tested bacteria strains TA98 and TA100. For TA98 tester strain, percentage inhibition values against AFB1 mutagenicity from 61 to 93, and 38 to 75 for flavonoid and anthocyanin extracts were obtained. The total phenol and anthocyanin contents correlate with the observed antioxidant capacity. The most biological active corn samples were the blue color while the least actives were the red ones. The results show that the studied blue corn samples are good sources of antioxidant and antimutagenic compounds, which could use to develop products that contribute to human health.

A comparative study on the biological activity of essential oil and total hydro-alcoholic extract of Satureja hortensis L.

Satureja hortensis L. presents an increased interest due to its chemical composition, abundant in monoterpenes, aglyconic and glycosylates flavonoids, and phenolic acids, leading to important biological activity. The present study compared the biological activity of volatile oil (VO) and total hydro-alcoholic extract (TE) of Satureja hortensis L. in terms of: i) antioxidant activity; ii) antimicrobial activity; and iii) viability, migration and proliferation on two healthy cell lines (keratinocytes-HaCaT and fibroblasts-1BR3) and two melanoma cell lines (human-A375 and murine-B164A5). Antioxidant activity of VO and TE showed maximal values around 72%. Antimicrobial screening highlighted the inhibitory capacity of VO against all seven tested bacteria strains, with the most pronounced effect against S. aureus and C. albicans, while TE exerted only a slight activity against three bacteria strains. VO showed greater efficacy than TE on both tumor cell lines (A375 and B164A5), the activity of the compounds was higher when low concentrations were used (5, 10 and 25 µM) while at high concentrations (50 and 100 µM) the percentages of viability were increased.

Essential Oil Composition and Biological Activity of "Pompia", a Sardinian Citrus Ecotype.

Pompia is a Sardinian citrus ecotype whose botanical classification is still being debated. In the present study, the composition of Pompia peel essential oil (EO) is reported for the first time, along with that of the leaf EO, as a phytochemical contribution to the classification of this ecotype. The peel EO was tested for its antioxidant ability (with both the 2,2-diphenyl-1-picarylhydrazyl (DPPH) and ferric reducing antioxidant power (FRAP) assays). Moreover, its antimicrobial activities were tested for the first time on dermatophytes (Microsporum canis, Microsporum gypseum, and Trichophyton mentagrophytes), on potentially toxigenic fungi (Fusarium solani, Aspergillus flavus, and Aspergillus niger) as well on bacteria (Escherichia coli, Staphylococcus aureus, and Staphylococcus pseudointermedius). The dominant abundance of limonene in the peel EO seems to distinguish Pompia from the Citrus spp. to which it had previously been associated. It lacks γ-terpinene, relevant in Citrus medica EO. Its relative content of α- and β-pinene is lower than 0.5%, in contrast to Citrus limon peel EO. Pompia peel and leaf EOs did not show significant amounts of linalool and linalyl acetate, which are typically found in Citrus aurantium. Pompia peel EO antioxidant activity was weak, possibly because of its lack of γ-terpinene. Moreover, it did not exert any antimicrobial effects either towards the tested bacteria strains, or to dermatophytes and environmental fungi.

Egg proteins stabilized green silver nanoparticles as delivery system for hesperidin enhanced bactericidal potential against resistant S. aureus

Nano-carriers enhance drugs stability and solubility and prevent their rapid degradation. Silver nanoparticles (AgNPs) are preferable for drug delivery applications due to their unique properties and less toxicity. Protein AgNPs are versatile nano-carriers as they provide the anchoring layer for drug molecules to be transported into cells. Herein, the development of a simple method for the synthesis of egg proteins stabilized AgNPs and their use as nano-carrier for hesperidin is reported. Protein stabilized AgNPs were characterized through UV–Vis spectrophotometer, FT-IR, zetasizer and atomic force microscope (AFM). The bactericidal potentials of hesperidin loaded AgNPs were studied against sensitive and multidrug-resistance bacteria strains via Tetrazolium Microplate Assay. UV–visible spectrum showed peak that corresponds to the plasmon absorbance of AgNPs. FT-IR study reveals bands which indicate effective capping of AgNPs with egg proteins. AgNPs were found spherical in nano-range size with negative charge and loaded increased amount of hesperidin. An increased bactericidal activity of hesperidin was observed against tested bacteria strains upon loading in AgNPs. Current findings suggest a facile approach for proteins stabilized AgNPs and their potential as effective nano-carrier for enhancing the bactericidal activity of hesperidin.

Diversity, antibacterial activites and growth promoting characteristics of endophytic fungi from sandal (Santalum album)

The aim of this study was to investigated the biological diversity, antibacterial activites and the plant growth-promoting traits of endophytic fungi of sandal (Santalum album), and to assess their potential in the development of antibacterial substances and rapid cultivation of sandal. The results of isolation and taxa analysis of endophytic fungi from sandal showed that 325 strains of endophytic fungi belonging to 16 genera of endophytic fungi were isolated from sandal (of which 86 from roots, 105 from stems and 134 from leaves). The isolation rate and colonization rate of endophytic fungi in different sandal parts showed the same pattern of change: leave>stems>roots. The diversity index of endophytic fungi in sandal roots was significantly higher than that of stems and leaves. The dominant endophytic fungi of sandal roots, stems and leaves showed significant differences. The dominant endophytic fungi of roots were Fusarium (50.00%) and Alternaria (10.47%), Alternaria (58.11%) and Acremonium (20.00%) for stems, and Pantoea (74.63%) for leaves. The antibacterial activity of 40 representative strains of sandal endophytic fungi were analyzed and the results showed that 90% of endophytic fungi exhibited inhibitory activity against at least one of the tested bacteria strains, and the strains with inhibitory activity to Escherichia coli, Enterobacter aerogenes, Shigella dysenteriae, Salmonella typhimurium, Staphylococcus aureus, and Bacillus subtilis accounted for 45.0%, 30%, 47.5%, 55%, 72.5%, and 62.5%, respectively. The sandal fungal endophytes with plant growth-promoting characteristics were screened, and 5 strains of endophytic fungi with phosphorus-solubilizing activity, 8 strains of endophytic fungi producing IAA, and 4 strains of endophytic fungi producing siderophores were found. Among them, endophytic fungus Monilia sp TXRF45 clould produced IAA and siderophores, and also show phosphate-solubilizing activity. The results indicated that the endophytic fungi of Sandal were rich in species diversity and their distribution had a certain tissue specificity. Some strains showed good antibacterial activity and growth-promoting properties, which could potentially applicable for the development of antibacterial substances and rapid cultivation of sandal.

Two new triterpenoids with antimicrobial activity from the leaves and twigs of Orophea yunnanensis

Two new triterpenoids, 3-O-(4’,5’-dihydroxybenzoyl)-lup-20(29)-en (1) and 3-O-(6’-desmethysyringyl)-13α-methyl-27-norolean-14-en-3β-ol (2), were isolated from the leaves and twigs of Orophea yunnanensis. Their structures were identified by extensive spectroscopic experiments (NMR and MS) and comparison with literature data. Compounds 1 and 2 exhibited the moderate inhibitory activity against Sclerotinia sclerotiorum, Ceratocystis fimbriata and Verticillium dahliae Kleb with MIC values from 50 to 25 μg/mL, and also displayed the weak activity selectively against tested bacteria strains with MIC values from 100 to 50 μg/mL.

Isolation and Antimicrobial Activity of Coumarin Derivatives from Fruits of Peucedanum luxurians Tamamsch.

As a continuation of searching for phytoconstituents that act as promising agents for antimicrobial therapy, rare coumarins were isolated from fruits of Peucedanum luxurians and tested. In a first step, the content of major compounds in the aerial parts and fruits of P. luxurians were compared. The results clearly showed that the fruits with dichloromethane as a solvent yielded, in most cases, higher concentrations of almost all the analyzed coumarins than the aerial parts, with peucedanin detected as the most abundant compound with a concentration of 4563.94 ± 3.35 mg/100 g. Under this perspective, the dichloromethane extract from the fruits of P. luxurians was further submitted to high performance countercurrent chromatography with a mixture of n-hexane, ethyl acetate, methanol, and water 6:5:6:5 (v/v). Combination of HPCCC and prep-HPLC yielded 6′,7′-dihydroxybergamottin (1), officinalin (2), stenocarpin isobutyrate (3), officinalin isobutyrate (4), 8-methoxypeucedanin (5), and peucedanin (6). Isolated compounds were tested against several Gram-positive and Gram-negative bacteria strains. 6′,7′-Dihydroxybergamottin, peucedanin, and officinalin isobutyrate appeared to be the most active against all tested bacteria strains with minimum inhibitory concentration (MIC) values between 1.20 and 4.80 mg/mL. To the best of our knowledge, this is the first report about countercurrent isolation of mentioned coumarins, as well as the first information about their antimicrobial activity.

A laboratory investigation of the antimicrobial activity of a selection of western phytomedicinal tinctures

IntroductionFollowing the observed success of a herbal cocktail in controlling and eliminating acute respiratory infections in a group of approximately sixty, 1–3 year old equines, it was decided to test ten of the herbs individually for antibacterial activity, using in vitro methodology. MethodsHydroethanolic extracts of defined concentration for each of the ten herbs were sourced from a licensed supplier in the UK. Positive and negative controls were included in the study.A quantitative suspension test for the evaluation of bactericidal activity of chemical disinfectants and antiseptics according to British Standard BS EN 1276:2009 was used to assess the anti-microbial activity of ten neat herbal tinctures. ResultsBactericidal activity is described as the capability of a product to produce at least a 5 log10 reduction in specified test organisms within 5 minutes when the disinfectant is tested at its intended use dilution(s). The performance of each neat herbal tincture in this study was assessed only under moderate to heavy (dirty) soiling conditions.Commiphora molmol, Inula helenium, and Thymus vulgaris showed antimicrobial activity against all three test strains of bacteria, and over the entire dilution range (10−1 to 10−7).Baptisia tinctoria, Echinacea pupurea, Marribium vulgare, and Salvia officinalis, showed maximum antimicrobial activity only to two of the three test organisms.The tinctures of Galium aperine and Glechoma hederacea showed zero to very low antimicrobial activity against the three test organisms. ConclusionA herbal formulation containing a blend of the ten tested herbs constitutes a powerful antimicrobial cocktail.

Antibacterial Activity of Polyphenols: Structure-Activity Relationship and Influence of Hyperglycemic Condition.

Polyphenols are plant-derived natural products with well-documented health benefits to human beings, such as antibacterial activities. However, the antibacterial activities of polyphenols under hyperglycemic conditions have been rarely studied, which could be relevant to their antibacterial efficacy in disease conditions, such as in diabetic patients. Herein, the antibacterial activities of 38 polyphenols under mimicked hyperglycemic conditions were evaluated. The structure-antibacterial activity relationships of polyphenols were also tested and analyzed. The presence of glucose apparently promoted the growth of the bacterial strains tested in this study. The OD600 values of tested bacteria strains increased from 1.09-fold to 1.49-fold by adding 800 mg/dL glucose. The polyphenols showed structurally dependent antibacterial activities, which were significantly impaired under the hyperglycemic conditions. The results from this study indicated that high blood glucose might promote bacterial infection, and the hyperglycemic conditions resulting from diabetes were likely to suppress the antibacterial benefits of polyphenols.

Design, synthesis, 3D pharmacophore, QSAR, and docking studies of some new (6-methoxy-2-naphthyl) propanamide derivatives with expected anti-bacterial activity as FABI inhibitor

Antibiotic resistance is a major health problem; so there is a emerging need for developing new antibiotic agents. A novel series of (6-methoxy-2-naphthyl) propanamide derivatives were synthesized and evaluated for their potential antibacterial activity. The minimum inhibitory concentration of these compounds were determined by microdilution technique against five known strains of bacteria. Test strains included three Gram-positive strains (Streptococcus pneumonia, Bacillus subtilis and Staphylococcus aureus) and two Gram-negative strains (Escherichia coli and Salmonella typhimurium). According to the observed antibacterial activity results showed that compounds N-(4-(2-(5-bromo-2-hydroxybenzylidene)hydrazine carbonyl) phenyl)-2-(6-meth oxynaphthalen-2-yl)propanamide 2d and N-(4-(2-(2,4-dichlorobenzylidene)hydrazine carbonyl)phenyl)-2-(6-methoxy-naphthalen-2-yl)propanamide 2j has potent antibacterial activity against B. subtilis (minimal inhibitory concentrations 1.95 µg/ml). Also 2-(6-methoxynaphthalen-2-yl)-N-(4-(2-(4-oxopentan-2-ylidene)hydrazinecarbonnyl)phenyl) propanamide 6 showed potent antibacterial activity against S. pneumonia (minimal inhibitory concentrations 1.95 µg/ml) compared to Naproxen (7.81, 15.63 µg/ml) and the reference drug Ampicillin (7.81 µg/ml). Two of the synthesized compounds, namely, 2j and 2k exhibited more potent antibacterial activity than the reference drugs (Gentamicin and Ampicillin) against all the test strains of bacteria. Molecular docking simulation was also carried out for Enoyl-aceyl carrier protein reductase enzyme, which is responsible for catalyzing the final step of bacterial fatty acid biosynthesis and is an attractive target for the development of novel antibacterial agents. In addition, generation of 3D pharmacophore model and quantitative structure–activity relationship models were combined to explore the structural requirements controlling the observed antibacterial properties.

Characterization of recombinant Trypanosoma brucei gambiense Translationally Controlled Tumor Protein (rTbgTCTP) and its interaction with Glossina midgut bacteria

ABSTRACTIn humans, sleeping sickness (i.e. Human African Trypanosomiasis) is caused by the protozoan parasites Trypanosoma brucei gambiense (Tbg) in West and Central Africa, and T. b. rhodesiense in East Africa. We previously showed in vitro that Tbg is able to excrete/secrete a large number of proteins, including Translationally Controlled Tumor Protein (TCTP). Moreover, the tctp gene was described previously to be expressed in Tbg-infected flies. Aside from its involvement in diverse cellular processes, we have investigated a possible alternative role within the interactions occurring between the trypanosome parasite, its tsetse fly vector, and the associated midgut bacteria. In this context, the Tbg tctp gene was synthesized and cloned into the baculovirus vector pAcGHLT-A, and the corresponding protein was produced using the baculovirus Spodoptera frugicola (strain 9) / insect cell system. The purified recombinant protein rTbgTCTP was incubated together with bacteria isolated from the gut of tsetse flies, and was shown to bind to 24 out of the 39 tested bacteria strains belonging to several genera. Furthermore, it was shown to affect the growth of the majority of these bacteria, especially when cultivated under microaerobiosis and anaerobiosis. Finally, we discuss the potential for TCTP to modulate the fly microbiome composition toward favoring trypanosome survival.

Effectiveness of cleaning-disinfection wipes and sprays against multidrug-resistant outbreak strains

Hospital rooms play an important role in the transmission of several health care-associated pathogens. During the last few years, a number of innovative cleaning-disinfecting products have been brought to market. In this study, commercially available products combining cleaning and disinfection were compared, using 2 different application methods. The aim was to determine which product was most effective in simultaneous cleaning and disinfection of surfaces. Seven cleaning-disinfecting wipes and sprays based on different active ingredients were tested for their efficacy in removal of microbial burden and proteins. Efficacy was tested with known Dutch outbreak strains: vancomycin-resistant enterococci (VRE), Klebsiella pneumoniae OXA-48, or Acinetobacter baumannii. For all bacteria, ready-to-use cleaning-disinfecting products reduced the microbial count with a log10 reduction >5 with a 5-minute exposure time, with the exception of a spray based on hydrogen peroxide. Omitting the aforementioned hydrogen peroxide spray, there were no significant differences between use of a wipe or spray in bacterial load reduction. Using adenosine triphosphate (ATP) measurements, a significant difference in log10 relative light units (RLU) reduction between various bacteria (P ≤ .001) was observed. In general, a >5 log10 reduction of colony forming units (CFU) for tested wipes and sprays was obtained for all tested bacteria strains, with exception of hydrogen peroxide spray and VRE. Although ATP may show a difference between pre- and postcleaning, RLU reduction does not correlate with actual CFU reductions.

Antibacterial and antibiotic resistance modulatory activities of leaves and bark extracts of Recinodindron heudelotii (Euphorbiaceae) against multidrug-resistant Gram-negative bacteria

BackgroundRecinodindron heudelotii (Euphorbiaceae) is a plant used in Africa, particularly in Cameroon to treat various ailments including bacterial infections. In this study, we evaluated the extracts of the leaves (RHL) and bark (RHB) of R. heudelotii for their antibacterial and antibiotic resistance modulating activities against 29 Gram-negative bacteria, including multidrug-resistant (MDR) phenotypes.MethodsThe broth micro-dilution assay was used to evaluate the antibacterial activity, and the antibiotic resistance modulating effects of the plant extracts.ResultsRHL displayed the most important spectrum of activity with minimal inhibitory concentrations (MICs) values ranging from 256 to 1024 μg/mL against 75.86% of the 29 tested bacteria strains while RHB was not active. RHL also showed killing effects with minimal bactericidal concentrations (MBCs) ranging from 256 to 1024 μg/mL. The activities of tetracycline and kanamycin associated with RHL were improved on 88.89% and 77.78% of the tested MDR bacteria, at MIC/2 at MIC/4 respectively, with 2 to 16-folds decreasing of MIC. This suggests the antibiotic resistance modulating effects of these antibiotics.ConclusionThe present study provides data indicating a possible use of the leaves extract of Recinodindron heudelotii alone or in association with common antibiotics in the fight against bacterial infections including those involving MDR bacteria.

Composition and anti-bacterial activity analysis of citronella oil obtained by hydrodistillation: Process optimization study

Hydro-distillation was performed to determine the quantity of essential oil in different parts of Java Citronella (Cymbopogon winterianus Jowitt) plant. Parameters affecting the oil extraction process were evaluated using Response Surface Methodology. The generated second order polynomial model was highly significant with R2=0.9744 and P<0.0001. Highest yield of 2.38% vw−1 was obtained using the leaves part at distillation time of 180min, which was about 40% more than stems part and 17% more than whole aerial parts. Higher essential oil content of fresh plant (2.43% on a dry weight basis) compared to dried plant (2.12% on a dry weight basis) indicates that the moisture content has a significant effect on oil yield. GC/MS analysis of the oil extracted from leaves part revealed about 95% of commercially important compounds viz. citronellal (55.23%), geraniol (26.29%) and citronellol (13.41%), indicated very high quality citronella oil. The oil was found effective against all the six tested bacteria strains namely Bacillus subtilis, Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia and Escherichia coli, which revealed that citronella oil could be applied for the treatment of infections caused by various gram positive or negative pathogenic organism. The hydrosol obtained after hydro-distillation was analyzed using HPLC and was found to contain sugar alcohols such as adonitol, erythritol and mannitol which could be utilized in nutraceutical industries.