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At least 163 records · Page 9Linked to original sources
PubMed2001

Genetic linkage between resistance to quaternary ammonium compounds and beta-lactam antibiotics in food-related Staphylococcus spp.

Little is known about the occurrence of antimicrobial resistance determinants in staphylococci isolated from food and food processing industries. Quaternary ammonium compound (QAC)-resistant coagulase-negative staphylococci (CNS) isolated from food and food-processing industries were investigated for the presence of genetic determinants (qacA/B and qacC/smr) encoding resistance to the QAC benzalkonium chloride (BC), several antibiotic resistance genes, and staphylococcal insertion sequences IS257 and IS256. Six qacA/B-harboring strains were resistant to penicillin and hybridized to a blaZ probe. The qacA/B and blaZ probes hybridized to plasmids of similar size in three isolates. Molecular and genetic characterization of the 23-kb plasmid (pST6) of Staphylococcus epidermidis St.6 revealed the presence of qacB adjacent to an incomplete beta-lactamase transposon Tn552 encoding the gene cluster blaZ, blaR, and blaI. Sequence analysis of flanking regions and the intergenic region between blaZ and qacB revealed the presence of IS257 downstream of blaZ as well as sin and binR between blaZ and qacB. In the three other BC and penicillin-resistant strains, the qacA/B and blaZ genes were located on separate plasmids. A qacC harboring S. epidermidis strain (St.17) also hybridized to tetK (tetracycline resistance) and ermB (erythromycin resistance) genes. The individual genes were located on separate plasmids, suggesting no linkage between QAC and antibiotic resistance determinants. Plasmid-free Staphylococcus aureus RN4220 allowed uptake of the pST6 plasmid DNA, indicating that the resistance genes could potentially be transferred to pathogens under selective stress. In conclusion, presence of both resistance determinants could lead to co-selection during antimicrobial therapy or disinfection in hospitals or in food industries.

Anti-Bacterial Agents↗
PubMed2006

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part I. Application to surface, waste and indirect discharge water samples in Austria.

A method for simultaneous quantitative determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds (QACs) has been developed, validated and subsequently applied to real water samples in Austria. The method employs liquid-liquid extraction (LLE) followed by liquid chromatography/tandem mass spectrometry (LC-MS/MS), using electrospray ionization (ESI) in positive mode. The overall method quantification limits range from 4 to 19ng/L for the enrichment of 500mL water samples and analyte recoveries are between 80 and 99%. The method was applied to 62 of the respective water samples without filtration to avoid the loss of the analytes due to the high adsorption capacity of these compounds. Maxima in the mg/L range, especially in the wastewater of hospitals and laundries, could be detected for the selected target compounds.

Austria↗
PubMedDate not supplied

[The search for selective blockers of NMDA and AMPA/kainate receptors in a series of bis-ammonium compounds with adamantyl radicals].

Two groups of substances capable of selectively blocking the NMDA and AMPA/kainate receptors in experiments on intact animals were found in a series of bis-ammonium compounds with adamantyl radicals. The selective NMDA receptor blockers (IEM-1754, IEM-1755, IEM-1752), as well as the reference agents MK-801 and memantine, produced anticonvulsant, anti-ischemic, and antihypoxant effects and prevented the loss of experimental animals from toxic doses of NMDA. The selective AMPA/kainate receptor blockers (IEM-1553, IEM-1751, IEM-1592, and DNQX)) also produced the anticonvulsant, anti-ischemic, and antihypoxant effects, but did not prevent from the loss of animals caused by the toxic doses of NMDA. The maximum activity was observed for IEM-1754, the activity of which exceeded that of MK-801 (by a factor of 5-10) and memantine (by a factor of 300-800) in all the test objects.

Adamantane↗
PubMed1990

Gametocytogenesis induction by ammonium compounds in cultured Plasmodium falciparum.

Asexual parasites of a strain that seldom or never produce gametocytes in in vitro culture began gametocytogenesis after 24 h treatment with RPMI 1640 medium containing concanavalin A (final concentration, 10 micrograms ml-1) and ammonium carbonate (final concentration, 15 mM ml-1) or ammonium bicarbonate (final concentration, 15 mM ml-1). Gametocytogenesis was consistently observed from the 3rd day after the treatment. Concanavalin A enhanced gametocytogenesis induction by ammonium carbonate or ammonium bicarbonate, although concanavalin A does not itself have gametocytogenesis induction activity. Whereas no gametocytogenesis was observed after addition of concanavalin A and ammonium acetate (final concentration, 5-25 mM ml-1) or ammonium chloride (final concentration, 5-15 mM-1). Addition of ammonium compounds resulted in decrease of parasitemia, regardless of gametocytogenesis.

Animals↗
PubMed2006

Synthesis and biological properties of gemini quaternary ammonium compounds, 5,5'-[2,2'-(alpha,omega-polymethylnedicarbonyldioxy)diethyl]bis-(3-alkyl-4-methylthiazolium iodide) and 5,5'-[2,2'-(p-phenylenedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium bromide).

We synthesized gemini quaternary ammonium compounds (gemini QACs) having two thiazolium moieties in a molecule, 5,5'-[2,2'-(alpha,omega-polymethylnedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium iodide) (5DEBT-m,n), on which the carbon number of the methylene chain linking the two thiazoles (m) is 2, 6 or 8 and that of the alkyl group (n) is 8, 10, 12, 14 or 16. 5,5'-[2,2'-(p-Phenylenedicarbonyldioxy)diethyl]bis(3-alkyl-4-methylthiazolium bromide) (5DEBT-P,n) was then synthesized, which is composed of a p-phenylene as the methylene spacer. For five gemini QAC series, in addition to the previously described 5DEBT-4,n to the four new compound series, their antimicrobial activities were determined. 5DEBT-m,10 and -P,10 exhibited a wide and strong bacteriostatic activity against gram-negative and -positive bacteria, fungi and then yeast in comparison with N-tetradecyl-5-(2-hydroxyethyl)-4-methylthiazolium iodide as a mono-QAC. The bactericidal activity of the 5DEBT series against Escherichia coli IFO 12713 and Staphylococcus aureus IFO 12732 was investigated on the basis of the effects of their alkyl chain length and their molecular hydrophobicity. It was found that the effect of theses factors on their activity significantly changes by the difference between the gram-negative and -positive bacteria. Although against the gram-negative bacterium, the change in the activity due to extension of the alkyl group for each compound affected the kind of methylene spacer, against the gram-positive bacterium, it was almost equal in spite of the methylene spacer. This result could be responsible for the bactericidal mechanism of the gemini QACs being influenced by the diversity of the steric structure participating in the methylene chain length and by the bacterium cell surface hydrophobicity.

Alkylation↗
PubMed1998

[Lipid peroxidation and the role of quaternary ammonium compounds in normalizing this process].

Regulation of lipid peroxidation is realized not only by antioxidant enzymes but by natural antioxidants as well. We have lately succeeded, together with the students, in identifying antioxidant properties of quaternary ammonium compounds, which fact makes it possible for the above properties to gain extensive applicability in a setting where there is this variety of disbolism. One of such drug preparations is ethonium. The article contains information about uses of ethonium in the tablet dose form. The tablets are of little toxicity, they stimulate the oxidation-reduction processes and proved to be effective in experimental gastric and duodenal ulcers.

Adult↗
PubMed1998

Determination of antibacterial quaternary ammonium compounds in lozenges by capillary electrophoresis.

A method for the specific determination of three quaternary ammonium compounds, benzalkonium chloride, cetylpyridinium chloride and dequalinium chloride, used as antibacterial agents in candy-based lozenges, is described based on capillary zone electrophoresis. It is shown that, following optimisation of buffer composition with respect to organic modifier concentration. pH and buffer concentration together with the inclusion of sodium dodecylsulphate as an ion-pairing agent in the case of dequalinium chloride, these analytes migrate in less than 5 min. The resultant electrophoretic peaks are sharp and readily quantified. The individual alkyl components of benzalkonium chloride can be resolved as can related impurities in dequalinium chloride lozenges. The quantitative characteristics of the assay method, based on peak areas normalised with respect to migration times, are reported and the method is compared with a previously published method based on liquid chromatography.

Anti-Infective Agents↗
PubMed1975

Effects of the quaternary ammonium compound OX-572 on ventricular tachyarrhythmias complicating acute myocardial infarction.

Patients with acute myocardial infarction who developed defined ventricular tachyarrhythmias were randomly allocated to two groups. The patients (n=34) in one of the groups received the quaternary ammonium compound N,N-bis (phenylcarbamoylmethyl) dimethylammoniumchloride (QX-572) intravenously as an infusion of 8 mg/kg body weight over 30 minutes. The patients in the other group (n=33) received saline and acted as controls. The analysis of arrhythmias was based on a continuous electrocardiogram recorded in parallel to routine monitoring during the 24 hours after the start of infusion. Only the detection of ventricular tachycardia or the development of ventricular fibrillation on routine monitoring could induce a change in antiarrhythmic treatment. The incidence of patients with ventricular tachycardia recorded was significantly lower in the QX-572 group (38%) than in the control group (73%). About half the number of patients with ventricular tachycardia recorded on the continuous electrocardiogram were also detected by means of routine monitoring. The number of patients with various types of ventricular premature contractions (1-5/min, greater than 5/min, paired, multifocal, R on T), ventricular tachycardia, and rapid idioventricular rhythm were compared within successive one-hour periods. For all types of ventricular tachyarrhythmias except rapid idioventricular rhythm there was a lower incidence of arrhythmias in the QX-572 group...

Adult↗
PubMedDate not supplied

Ototoxic effect of quaternary ammonium compounds.

In earlier investigations by the author it has been shown that chlorhexidine, when introduced into the middle ear of guinea pigs, caused serious damage to the inner ear. The present investigation was performed in order to study if the quaternary ammonium compounds benzethonium chloride and benzalkonium chloride, frequently used for skin disinfection, can also induce inner ear damage when introduced into the tympanic cavity of guinea pigs. The disinfectants in question, at a concentration of 0.1% and in a solution of aqua dest. or 70% alcohol, were introduced into the animals' middle ear for exposure times of 10, 30, or 60 min. The animals were sacrificed 2 or 9 weeks after the exposure and the organ of Corti and vestibular neuroepithelia were studied as surface preparations with phase contrast microscopy. It was found that most of the ears exposed to the disinfectants had suffered damage, affecting both the vestibular and cochlear parts of the inner ear. The extent of the damage was related both to the duration of exposure and to the length of the animals' survival after the exposure. Furthermore it was found that the tympanic cavity and the perilymphatic spaces of vestibulum and cochlea were pathologically changed.

Acoustic Maculae↗