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Uptake of quaternary ammonium compounds into rat liver plasma membrane vesicles.

In order to elucidate the mechanism by which quaternary ammonium compounds are transported across the rat hepatocyte plasma membrane, the transport of five quaternary ammonium compounds through rat hepatocyte plasma membrane vesicles was investigated. Transport is only observed when the organic cations possess a high lipophilicity. Uptake appeared to be a passive process and was not stimulated by a transmembrane electrical potential difference nor by the presence of an excess of anions like I-. Taurocholate decreased the uptake. However in the presence of a catalytic amount of tetraphenylborate a transmembrane electrical potential difference (inside negative) stimulated the uptake.

Animals↗

New biomaterials through surface segregation phenomenon: new quaternary ammonium compounds as antibacterial agents.

Five new trisiloxane quaternary ammonium compounds were synthesized from hydrotrisiloxane with allyl glycidyl ether to yield the epoxy function. Various amines were then reacted to yield trisiloxane amines which were further reacted to methyl substitute or oxidize the beta-carbons in order to provide thermal stability. These new compounds were employed as melt additives in a nonwoven polypropylene fiber extrusion process to produce, through surface segregation, a new biomaterial with antibacterial properties.

Amines↗

Syntheses and antimicrobial activities of a series of new bis-quaternary ammonium compounds.

A series of new bis-quaternary ammonium compounds (bis-QACs), 4,4'-(2,9-dioxadecane) bis(1-alkylpyridinium bromide)s, 3,3'-(2,9-dioxadecane)bis(1-alkylpyridinium bromide)s and 3,3'-(2,7-dioxaoctane)bis(1-decylpyridinium bromide) was synthesized. The compounds were evaluated by their activities against bacteria, molds and yeasts; the activities were expressed as the minimum inhibitory concentrations (MIC) and/or the minimum bactericidal concentrations (MBC). Compound 4,4'-(2,9-dioxadecane) bis(1-decylpyridinium bromide) had MIC values which exceeded those of benzalkoniumchloride and thiabendazole. It was in vitro active against a broad spectrum of Gram-negative and Gram-positive bacteria, against yeasts and some molds, it had high solubility and thermal decomposition temperature. The relationships between structure and biological activity of the tested bis-QACs are discussed.

Anti-Bacterial Agents↗

Correlation between the bacterioclastic action of a bis-quaternary ammonium compound and outer membrane proteins.

Bis-quaternary ammonium compounds (bis-QACs) have the ability to cause a rapid and abundant leakage of the turbid materials from cells, and such a bacterioclastic ability leads to a potent bactericidal activity. In order to clarify the detailed mechanism of the bactericidal action of bis-QACs, the correlation between the bacterioclastic action of 4,4'-(1,6-hexamethylenedithio)bis(1-octylpyridinium bromide) (4DTBP-6,8) and the leakage of outer membrane pore protein E (OmpE) was investigated. Using the antiserum against a fusion protein consisting of GST and the OmpE protein of Escherichia coli encoded by the ompE gene, it was seen that the leakage of OmpE from E. coli cells was caused by treatment with low concentrations (much lower than the critical vesiculation concentration) of 4DTBP-6,8. Furthermore, it was confirmed that 4DTBP-6,8 caused an increase in the turbidity of the cell suspension of Klebsiella pneumoniae, Salmonella typhimurium and Serratia marcescences, and led to the leakage of several proteins which have a high percentage of homology with OmpE of E. coll. By immunoelectron microscopy investigation, it was revealed that the vesiculation from E. coli treated with 4DTBP-6,8 contains OmpE. In addition, the bacteriolytic action of 4DTBP-6,8 was investigated. The results suggested that the lysis of cells by bis-QACs was not an enzymatic action such as that by autolysin but a physical bacterioclastic action. Judging from these results, it is suggested that the leakage of OmpE is one of the major bacterioclastic actions of bis-QACs, and deals the bacterial cells a fatal blow.

Anti-Bacterial Agents↗

Plasmid-borne smr gene causes resistance to quaternary ammonium compounds in bovine Staphylococcus aureus.

Resistance to quaternary ammonium compounds (QAC) in staphylococci is common in hospital environments and has been described in the food industry. Little is known about staphylococcal QAC resistance associated with animal disease, although such disinfectants are widely used in veterinary medicine. In order to investigate the occurrence of QAC resistance in staphylococci isolated from QAC-exposed animals, 32 penicillin- and tetracycline-resistant and 23 penicillin- and tetracycline-susceptible Staphylococcus aureus isolates collected from milk from cows with mastitis during a 4-year period were selected for QAC susceptibility studies and genetic characterization. The isolates originated from four different herds that used a common pasture with a joint milking parlor in the summer. During the pasture season, a teat cream containing the QAC cetyltrimethylammonium bromide had been used daily for more than 10 years for mastitis control. Three of the penicillin- and tetracycline-resistant isolates, which were recovered from three different cows during a 20-month period, were resistant to QAC. Plasmid analysis, PCR, and DNA sequencing revealed a novel plasmid of 2,239 bp containing the smr gene. The plasmid, designated pNVH99, has similarities to small, smr-containing staphylococcal plasmids previously found in human and food isolates. pNVH99 is a new member of the pC194 family of rolling-circle replication plasmids. The three QAC-resistant isolates, as well as 28 of the 29 remaining penicillin- and tetracycline-resistant isolates, were indistinguishable by pulsed-field gel electrophoresis. The study indicates that the occurrence and spread of QAC-resistant S. aureus among dairy cows may be a problem that needs further investigation.

Amino Acid Sequence↗

The extraction and analysis of quaternary ammonium compounds in biological material by GC and GC/MS.

An injection port pyrolysis method for the analysis of quaternary ammonium compounds is reported. Identification and confirmation of the analyte was accomplished by gas chromatography/mass spectrometry. With minor modifications to pH used and solvent composition, a common ion-pair method of extraction of quaternary ammonium compounds from biological matrices with an iodide counter ion is described. Although the combined extraction-identification methodology was limited to neostigmine, succinylcholine, and paraquat, it should easily be applicable to any of the other compounds examined in this study.

Chromatography, Gas↗

Interaction of tertiary amines and quaternary ammonium compounds with gastrointestinal mucin.

The binding property of some tertiary amines (chlorpromazine, promethazine and imipramine) and quaternary ammonium compounds (propantheline, mepenzolate and butylscopolamine) for gastric mucin was investigated. All tertiary amines tested bound gastric mucin to varying extents, and the binding of chlorpromazine was especially strong. Moreover, the absorption behaviors of chlorpromazine in rat intestinal loops was significantly inhibited in the presence of gastric mucin. On the contrary, all quaternary ammonium compounds tested did not bind gastric mucin and the absorption of propantheline was not affected in the presence of gastric mucin. These results suggested that gastrointestinal mucin produced a significant effect on the bioavailability of these tertiary amines after oral administration.

Amines↗

Low sensitivity of Listeria monocytogenes to quaternary ammonium compounds.

Ninety-seven epidemiologically unrelated strains of Listeria monocytogenes were investigated for their sensitivities to quaternary ammonium compounds (benzalkonium chloride and cetrimide). The MICs for seven serogroup 1/2 strains were high. Three came from the environment and four came from food; none were isolated from human or animal samples. All 97 strains carried the mdrL gene, which encodes a multidrug efflux pump, and the orfA gene, a putative transcriptional repressor of mdrL. The absence of plasmids in four of the seven resistant strains and the conservation of resistance after plasmid curing suggested that the resistance genes are not plasmid borne. Moreover, PCR amplification and Southern blot hybridization experiments failed to find genes phylogenetically related to the qacA and smr genes, encoding multidrug efflux systems previously described for the genus Staphylococcus. The high association between nontypeability by phages and the loss of sensitivity to quaternary ammonium compounds are suggestive of an intrinsic resistance due to modifications in the cell wall.

Antiporters↗

The analysis of quaternary ammonium compounds in human urine by direct inlet electron impact ionization mass spectrometry.

An accurate and rapid screening test for nine quaternary ammonium compounds (suxamethonium chloride, pancuronium bromide, ambenonium chloride, benzethonium chloride, distigmine bromide, methylbenactyzium bromide, neostigmine bromide, propantheline bromide and pyridostigmine bromide) by direct inlet electron impact ionization mass spectrometry (DI/EI-MS) was investigated. Each compound was extracted from urine as an ion pair with KI3 into dichloromethane. The reliability of the identification of these compounds was verified by the mass chromatographic analysis of their characteristic fragment ions. The analysis of these drugs by DI/EI-MS could be performed within 5 min. The detection limits were between 20-150 ng/ml for the nine compounds. This method appears to be efficient, rapid and suitable as a screening procedure for the quaternary ammonium compounds found in urine.

Gas Chromatography-Mass Spectrometry↗

Effectiveness of sanitation with quaternary ammonium compound or chlorine on stainless steel and other domestic food-preparation surfaces.

The relative ability of various materials used for domestic and/or food-service sinks and countertops to be sanitized was determined. Both smooth (unused) and abraded surfaces were tested by exposure to 200 mg of quaternary ammonium compound per liter or 200 mg of sodium hypochlorite per liter. Surface materials tested included mechanically polished (type 304, #4 finish) and electropolished stainless steel, polycarbonate, and mineral resin. Surfaces were prepared for testing by allowing attachment of a Staphylococcus aureus culture for 4 h to achieve an initial attached population of 10(4) to 10(5) CFU/cm2. The test procedure involved immersion of the surface in sanitizer solution followed by wiping with a sanitizer-saturated cloth. Residual staphylococci were detected by overlaying agar directly on the treated surface. Results indicated that the stainless steels and the smooth polycarbonate, which had 0.5 log CFU/cm2 or fewer of residual staphylococci, were more readily sanitized by quaternary ammonium compound than were either the mineral resin surfaces, which had nearly 2.0 log CFU/cm2 of residual staphylococci, or the abraded polycarbonate which had nearly 1.0 log CFU/cm2 of residual staphylococci. Chlorine was most effective on the mechanically polished stainless steel, the unabraded electropolished stainless steel, and the polycarbonate surfaces, reducing cell populations to less than 1.0 log CFU/cm2. Chlorine was less effective on abraded electropolished stainless steel and mineral resin surfaces, where populations remained greater than 1.0 log CFU/cm2. Sanitation with quaternary ammonium compound or chlorine reduced S. aureus populations more than 1,000-fold on all surfaces except unabraded mineral resin.

Bacterial Adhesion↗