Effects of LPS, lipid A and polysaccharide from adapted strains of Escherichia coli on human leucocyte activity.

Polysaccharide and lipid A are responsible for the wide-ranging pharmacological activity of bacterial lipopolysaccharides (LPS). The alterations in LPS structure result in various effects on different functions of the target cells. The effects of LPS substructures, the polysaccharide (P) and lipid A (L) from E. coli on the innate mechanisms of human leucocytes were examined and compared in this study. Incubation of leucocytes with LPS and L and P analogues (1 and 100 microg/ml) enhanced their biological activity in dependence on their structure. These results showed that LPS was a less active immunomodulator of leucocytes than L and P analogues isolated from E. coli strains adapted to antimicrobial agents.

Activation of human leukocytes by lipid A from E. coli strains adapted to quaternary ammonium salt and amine oxide.

The immunomodulatory activities of monophosphoryl lipid A (MLA) and diphosphoryl lipid A analogues obtained from the sensitive strain of E. coli and from the resistant strains adapted to a quaternary ammonium salt and an amine oxide were compared. All analogues considerably stimulated the activity of human leukocytes although the analogue from the sensitive strain at a higher concentration significantly suppressed phagocytosis. The MLA analogue exhibited a suppressive effect on the microbicidal activity of human leukocytes against E. coli and the peroxidase activity. Adaptation of bacteria to amphiphilic antimicrobial compounds, which is accompanied by chemical changes in their lipid A, only slightly reduced their immunomodulatory activity when compared with the analogue from the sensitive strain. On the other hand, the diphosphoryl analogues were less active than MLA.

Antibacterial and Antifungal Activity of Zinc(II) Carboxylates With/Without N-Donor Organic Ligands.

The antibacterial and antifungal activity of zinc(II) carboxylates with composition Zn(RCOO)(2)*nH(2)O(R =H-, CH(3) (-), CH(3)CH(2)CH(2) (-), (CH(3))(2)CH-, XCH(2) (-), X=Cl, Br, I, n=0 or 2), [ZnX(2)(Nia(+)CH(2)COO(-))(2)](Nia=nicotinamide, X=Cl, Br, I) and [Zn(XCH(2)COO)(2)(Caf)(2)]*2H(2)O (Car=caffeine, X=Cl, Br) is studied against bacterial strains Staphylococcus aureus, Escherichia coli and yeast Candida albicans. The structural types are assigned to the prepared compounds and the influence of (i) carboxylate chain length, (ii) substitution of hydrogen atom of carboxylate by halogen and (iii) presence of N-donor organic ligands on the biological activity is discussed.

[Antimicrobial activity of (N-salicylidene-DL-aspartate- and (N-salicylidene-L-asparaginate)-copper complexes with pyrazole-type ligands]. / Antimikróbna aktivita (N-salicylidén-DL-aspartáto)- a (N-salicylidén-L-asparagináto) mednatých komplexov s ligandmi pyrazolového typu.

By a reaction of salicylaldehyde (Scl) with the corresponding amino acids and by the next complexation reaction of the formed Schiff bases with Cu2+ ions in an aqueous-alcoholic medium, aqua (N-salicylideneaminoalkanoato)copper(II) complex chelates of the composition Cu(Scl-DL-Asp(2-)) (H2O)2, Ip and Cu(Scl-L-Asn(2-)(H2O), In were prepared. The monodiazole complexes with pyrazole IIp and IIn (as monohydrate) as well as with 3,5-dimethylpyrazole IIIp a IIIn were prepared by replacing the molecule of H2O in the parent aquacomplexes with the diazoles under the same reaction conditions. Using a routine dilution micromethod, the antimicrobial activity of the prepared complexes and free diazoles was tested against Staphylococcus aureus, Escherichia coli and Candida albicans. Only a significant antistaphylococcus activity was found (highest for the complex IIn; MIC = 39 micrograms/cm3). All chelates (Ip,n-IIIp,n) were more effective (MIC = 39-156 micrograms/cm3) than both pyrazole (312 micrograms/cm3)and 3,5-dimethylpyrazole (625 micrograms/cm3) alone. The relationship between the coordination-chemical properties and the biological effects of the complexes studied is discussed.

Stereoisomeric effect on antimicrobial activity of a series of quaternary ammonium salts.

Two homologous series of diastereoisomeric racemic +/- cis and +/- trans-N,N-dimethyl-N-alkyl-2-benzoyloxycyclohexylmethylammonium bromides with the number of carbon atoms in the alkyl chain from six to twenty (m = 6,8 ... 20) were synthesised. Their structures have been elucidated by IR, UV and in some cases also with 1H and 13C NMR spectrometry. The title compounds were assayed for their antimicrobial activity on microorganisms S. aureus, E. coli and C. albicans. The highest antimicrobial activity was observed against S. aureus (log 1/MIC = 5.5 mol-1 dm3) and the lowest against E. coli (log 1/MIC = 4.5 mol-1 dm3). The +/- cis and +/- trans stereoisomers of all eight couples of diastereoisomeric compounds show differences in their physico-chemical characteristics (including partition coefficient and lipophilicity) which is also reflected in the different antimicrobial activity of these diastereoisomers.

Transduction of antibiotic resistance including imipenem resistance by wild type phages from nosocomial strains of Pseudomonas aeruginosa.

In this report we describe transduction of antibiotic resistance determinants by three wild type bacteriophages isolated from three Pseudomonas aeruginosa strains. The strains showed evident plaques of a lysis caused by a bacteriophage. The strains were identified as lysogenic among 31 imipenem (IMP)-resistant P. aeruginosa strains isolated at the National Institute of Oncology in Bratislava. The carbenicillin (CAR) resistance determinant was transduced by all the three phages to four P. aeruginosa recipients-PAO-1670, ML-M-88, ML-1292 and ML-1008. The gentamicin (GEN) resistance was transduced to ML-1008 only. The kanamycin (KAN) resistance was transduced in the following systems (combinations): "phage AP-37 to M-88", "phage AP-38 to PAO-1670, ML-1292 and M-88", and "phage AP-40 to M-88". The IMP resistance determinant was transduced by all the three phages to P. aeruginosa recipient strains. All transductant colonies were tested for the presence of directly not selected but co-transduced resistance determinants. Whereas transductants selected on media with IMP were resistant to five antibiotics (IMP, CAR, streptomycin (STR), KAN and GEN), transductants selected on CAR, KAN, STR, or GEN were resistant to a block of four of these antibiotics but not to IMP.

Immunomodulatory activity of amphiphilic antimicrobials on mouse macrophages.

A quaternary ammonium salt (1-methyldodecyl)-trimethylammonium iodide, a structurally analogous amine oxide (1-methyldodecyl)-dimethylamine-N-oxide and the amine oxide lacking long alkyl chain trimethylamine-N-oxide were tested for their immunomodulatory activity. Inbred mice strain C57/BL6 were pretreated for 7 days by the compounds under study. The activity of elicited peritoneal macrophages was also tested. Both compounds have a long alkyl chain. In concentrations of 10(-6) M there was a significant increase of the phagocytic, candidacidal and lysozyme activities of the cells. We also observed a suppressed peroxidase activity. The colicidal activity of both the peritoneal and spleen cells were not affected. The amine oxide lacking the long alkyl chain has the same effect at high concentration. A similarity between the effects of the amphiphilic compounds on the macrophages and their antimicrobial efficacy elicits the conclusion that both activities are caused by their ability to interact with the cell membranes.

Suppression of virulence factors of pseudomonas aeruginosa by subinhibitory concentrations of quaternary ammonium salts.

The effect of subinhibitory concentrations (sub-MICs) of two homologous series of "soft" quaternary ammonium salts (QATs) upon the expression of phospholipase C (Pseudomonas aeruginosa strain 72/92), elastase, proteinase and permeability activity (P. aeruginosa 9/92) was studied. Both strains were isolated from the patients suffering from nosocomial infections. Phospholipase C was the most markedly inhibited enzyme. The inhibitory effect was directly proportional to the concentration of substances but the degree of inhibition in the two homologous series was different. In the second strain of P. aeruginosa its production of elastase, permeability factor and mainly its proteinase activity were less affected by the series of tested QATs. A significant inhibition of production of these factors was manifested only in higher concentrations particularly by the substances with longer alkyls. The effect of QATs on the production of virulence factors could be attributed to their influence on the metabolic activity of organisms.

Efficacy of new organic ammonium salts on Pseudomonas aeruginosa Salmonella typhimurium.

The inhibitory activities of four new homologous series of organic ammonium salts (OAS) were tested on bacterial strains isolated from patients. Two types of compounds are used: "hard" (group A) and three groups (B, C, D) of biodegradable "soft" OAS with metabolically labile CO or NH groups in their molecules. The strain Pseudomonas aeruginosa was isolated from the sputum of a patient with carcinoma. The strain Salmonella typhimurium was isolated from a patient with clinical diagnosis of diarrhea. In all homologous series, the antibacterial activity was increasing continuously with the length of alkyl chain up to dodecyl or tetradecyl, then the "cut off" effect was observed. The most active compounds from both "hard" and "soft" types had superior activity to commercial disinfectants. The strain of Pseudomonas aeruginosa was more sensitive to these compounds than that of Salmonella typhimurium.

Effect of quaternary ammonium salts and amine oxides on Pseudomonas aeruginosa.

Two quaternary ammonium salts, viz (1-methyldodecyl) trimethylammonium bromide (ATDBr) and tetramethylammonium bromide (TMABr), as well as two amine oxides, (1-methyldodecyl)dimethylamine oxide (ATDNO) and trimethylamine oxide (TMANO), were tested for their inhibitory activity on a Pseudomonas aeruginosa strain isolated from nosocomial infections. Only those compounds with long alkyl chains in their molecules (ATDBr and ATDNO) showed antimicrobial efficacy. In subinhibitory concentrations both compounds inhibited incorporation of [14C]-adenine and [14C]-leucine as precursors of macromolecular biosynthesis. Endogenous respiration of the cells was more sensitive to both agents than the respiration of various substrates. Among the virulence factors only the production of phospholipase C was inhibited by sub-MICs, while the activities of elastase and proteinase were stimulated until the inhibitory concentrations were reached. The short-chain analogues TMABr and TMANO did not show these effects. It is suggested that the production of virulence factors is affected by amphiphilic compounds due to their antimicrobial activity.

[Antimicrobial activity of diazole-(N-salicylidene-L-alpha- alaninato)-copper complexes]. / Antimikróbna aktivita diazol-(n-salicylidén-l-alpha-alanináto) mednatých komplexov.

The antimicrobial activities of a group of copper(II) chelates with the composition [Cu(TSB)(L)] or [Cu(TSB)(L')]. (TSB = N-salicylidene-L-alpha-alaninate dianion, L = imidazole and its alkyl derivatives, L' = pyrazole and 3,5-dimethylpyrazole) were studied. Bis-diazole complexes with L' = pyrazole and 3,5-dimethylpyrazole were found to be the most active against S. aureus (MIC = 78 and 20 micrograms.cm-3), less effective against C. albicans (156 micrograms.cm-3), T. terrestre and M. gypseum (100 micrograms.cm-3). The observed biological properties of complexes are discussed in relation to their proposed structures.

Primary biodegradation of amine oxide and quaternary ammonium amphiphiles.

Biodegradation of two amphiphilic "soft" antimicrobially active derivatives of lauric (dodecanoic) acid, a quaternary ammonium salt and an amine oxide bearing an amide or ester group, was followed using microorganisms from activated sludge. Primary biodegradation was determined by ion-selective electrodes, total biodegradation as the chemical oxygen demand. Though organic ammonium salts quickly undergo primary biodegradation, the rest of the molecule is difficult to destroy. In contrast, amine oxides are easily biodegradable.

[Immunochemical changes in the outer membrane of Escherichia coli adapted to amine oxides]. / Imunochemické zmeny vonkajsej membrány buniek Escherichia coli adaptovaných na amínoxidy.

Resistant strains of Escherichia coli were obtained by stepwise cultivation in subinhibitory concentrations of two antimicrobially active amine oxides. Changes in the chemical composition of the outer membrane of the resistant strains were accompanied also by different antigenic reactions. New precipitation lines were revealed by double immunodiffusion and immuno-electrophoretic methods. The results of immunochemical analysis confirm the findings that the resistance to amphiphilic compounds is associated with the outer membrane which limits the access of antimicrobially active molecules to their sites of action in the cytoplasmic membrane.

[Antimicrobial activity of selected aqua-carboxyl-cupric complexes]. / Antimikróbna aktivita vybraných akva-karboxylátomednatých komplexov.

The activity of compounds of different structural types of aqua-complexes of the composition Cu(R-COO)2.nH2O-methoxybenzoatocupric complexes, R = 2-, 3- and 4-methoxyphenyl (n = 1, 1 and 3); aryloxyacetatocupric complexes, R = phenoxymethyl (n = 3), 2-, 3- and 4-chlorophenoxymethyl (n = 4, 2 and 2) and 1-naphthoxymethyl (n = 4), and furthermore isomeric furanecarboxylato-(R = 2- or 3-furyl, n = 3, or 1) and thiophencarboxylatocupric complexes (R = 2- or 3-thienyl, n = 1 and 1), was examined by the methods of the 1st screening on selected anthropo- and phytopathogenic microorganisms. The effects of all aqua-complexes (suspension dosage form) on the representatives of bacteria and yeasts are minimal. On the other hand, the effect of these substances on the causative agents of dermatomycoses (Trichophyton terrestre, Microsporum gypseum) in the case of methoxybenzoato- and furoatocupric complexes achieves a MIC value of 500 micrograms/cm3 and lower. The activity against phytopathogenic fungi (both in vitro and in vivo experiments) is generally relatively low at 0.05% concentration of active ingredients (dispersible powders). At the same time the antimicrobial activity of the pertinent free carboxylic acids was investigated in relation to the cupric salts being formed. They are able to form the required pharmacoactive form prevalently as late as they are in the form of aqua-carboxylatocupric complexes.

Potassium leakage from Escherichia coli cells treated by organic ammonium salts.

The effect of the homologous series of 1,1-dialkylpiperidinium bromides on the potassium leakage from Escherichia coli cells has been studied. The minimum concentration for each compound which is able to release maximum of cellular potassium has been determined and correlated with the inhibitory activities of the compounds. The relationship between the structure and the activity enables to consider the K+ leakage as the marker of inhibitory activity of the membrane active antimicrobials.

Enhanced biodegradation of a hard bis-quaternary ammonium salt.

Bacterial strains with a high biodegradation potential were isolated from activated sludge. Their ability to decompose the hard bis-quaternary ammonium salt FB was determined by the method of chemical oxygen demand (COD) in a mineral medium, where the compound FB was the only source of carbon. The COD values were very low after 21 d and in the course of this period they reached zero level twice. The contribution of adsorption to decrease the COD value was small. The maximum COD decrease was accompanied by an increase of cell respiration. It is suggested that FB is effectively decomposed in spite of the fact that according to its structure it is a typical hard detergent.

[The effect of piperidinoethylesters of n-alkoxyphenyl-carbamic acids on bacterial cells]. / Pôsobenie piperidínoetylesterov n-alkoxyfenyl-karbámových kyselín na bakteriálne bunky.

The inhibitory effect of local anaesthetic agents of this type on the bacteria Escherichia coli were evaluated. The dependence between antimicrobial activity and structure (log 1/MIC = f/m) was studied with the use of a bilinear model. In the positional paraisomers a lower effect of spherical and electron effects than in the case of ortho- and meta-isomers is assumed. The efficacy of these agents depends on their lipophilicity. Membrane activity of these agents was confirmed. In subinhibitory concentrations they cause leakage of cytoplasmic material lysis of spheroplasts, they increase the permeability of the membrane for protons and inhibit dehydrogenase activity of cells. The mode of action of heptacainium chloride and its positional isomers on cells is identical and is similar as in organic ammonium salts and amine oxides.

Adsorption on bacterial spores depending on the aggregation properties of antimicrobial tensides.

A change in interaction with spores of Bacillus cereus occurred in the range of critical concentrations of micelle formation. With 1-methyldodecyldimethylamine-N-oxide and N,N'-bis(dodecyldimethyl)-1,2-ethanediammonium dibromide, the induced release of dipicolinic acid was blocked and the adsorption dynamics changed, respectively.