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A 20-year-old soldier caught an eczematous contact dermatitis on the left ear after the protection of hearing "Selektone" had been adapted. The protection of hearing had been disinfected before in a Zephirol solution 1% aqueous. Zephirol contains the quaternary ammonium compound Benzalkonium chloride. The problems of patch testing with Benzalkontium chloride are discussed.
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In this study, the influence of culturing Staphylococcus aureus and Pseudomonas aeruginosa under different growth conditions on their inactivation by the cationic active compounds benzalkonium chloride, chlorhexidine digluconate and octenidine dihydrochloride was investigated. Cells were grown in non-agitated tryptone soya broth as well as on tryptone soya agar according to national and international standards for evaluating chemical disinfectants. In quantitative suspension tests, cells of both test organisms grown on agar were significantly more sensitive to all three biocides than cells grown in broth. The differences in antimicrobial activity were greater in the case of S. aureus than in the case of P. aeruginosa. With S. aureus cultures, differences in the reduction factor of up to 5 log steps were found, with P. aeruginosa up to 2.5 log steps. The results of our uptake tests performed with S. aureus and octenidine dihydrochloride indicated that the growth conditions and the associated different stress factors either had an influence on the composition of the cell surface of this test organism or induced the formation of an efflux system. Cells of S. aureus cultured in broth took up only one-fifth of the amount of biocide molecules compared to cells from agar cultures. These data correlated with the results of the suspension tests. A low uptake of biocides apparently led to a reduced killing rate. In contrast to S. aureus, no significant differences in the uptake of octenidine dihydrochloride by cells of P. aeruginosa could be observed. These cells took up the same amount of the antimicrobial substance, whether on agar or in broth. In view of these results, possible consequences should be considered prior to changing test regulations.
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.
BACKGROUND: Quaternary ammonium compounds constitute a large group of antibacterial chemicals with a potential for inhibiting plaque and gingivitis. One compound, benzalkonium chloride (BC), may be of value, although there is a dearth of evidence to support efficacy. The aim of this study was to measure the ability of 2 BC mouthrinses (0.05% and 0.1%) to inhibit de novo plaque reformation. METHOD: A 4-day plaque regrowth model. For comparative purposes, a commercial mouthrinse containing cetyl pyridinium chloride (CPC) and a positive control chlorhexidine (CX) mouthrinse were also evaluated. RESULTS: Compared to water control, a reduction in plaque scores of 52% was noted for the CX mouthrinse, 22.5% for CPC and 5% and 6% for the 2 BC rinses. For plaque area, reductions of 84%, 47%, 16% and 15% were found for CX, CPC, and the 2 BC rinses, respectively. Significant reductions in plaque area compared to the water rinse were also seen with the 2 BC rinses (p<0.05). However, for both plaque score and plaque area, the CX and CPC rinses significantly reduced plaque compared to the BC rinses (p<0.0001). CONCLUSIONS: These findings would suggest that the 2 benzalkonium rinses would only have a limited value at inhibiting plaque formation.
The aim of this study was to investigate the mechanism of action of the preservative sodium chlorite (NaClO2), and the relationship with intracellular glutathione depletion. A detailed comparison of the dose responses of two cultured ocular epithelial cell types and four species of microorganism was carried out, and comparisons were also made with the quaternary ammonium compound benzalkonium chloride (BAK), and the oxidant hydrogen peroxide (H2O2). The viability of mammalian and microbial cells was assessed in the same way, by the measurement of intracellular ATP using a bioluminescence method. Intracellular total glutathione was measured by reaction with 5,5'-dithiobis-2-nitrobenzoic acid in a glutathione reductase-dependent recycling assay. BAK and H2O2 caused complete toxicity to conjunctival and corneal epithelial cells at approximately 25 ppm, in contrast to NaClO2, where > 100 ppm was required. The fungi Candida albicans and Alternaria alternata had a higher resistance to NaClO2 than the bacteria Staphyloccus aureus and Pseudomonas aeruginosa, but the bacteria were extremely resistant to H2O2. NaClO2 caused substantial depletion of intracellular glutathione in all cell types, at concentrations ranging from < 10 ppm in Pseudomonas, 25-100 ppm in epithelial cells, to > 500 ppm in fungal cells. The mechanisms of cytotoxicity of NaClO2, H2O2 and BAK all appeared to differ. NaClO2 was found to have the best balance of high antibacterial toxicity with low ocular toxicity. The lower toxicity of NaClO2 to the ocular cells, compared with BAK and H2O2, is in agreement with fewer reported adverse effects of application in the eye.
A standardized disinfectant test for Staphylococcus aureus cells in biofilms was developed. Two disinfectants, the membrane-active compound benzalkonium chloride (BAC) and the oxidizing agent sodium hypochlorite, were used to evaluate the biofilm test. S. aureus formed biofilms on glass, stainless steel, and polystyrene in a simple system with constant nutrient flow that mimicked as closely as possible the conditions used in the current standard European disinfectant test (EN 1040). The biofilm that was formed on glass contained cell clumps and extracellular polysaccharides. The average surface coverage was 60%, and most (92%) of the biofilm cells were viable. Biofilm formation and biofilm disinfection in different experiments were reproducible. For biofilms exposed to BAC and hypochlorite the concentrations needed to achieve 4-log killing were 50 and 600 times higher, respectively, than the concentrations needed to achieve this level of killing with the European phase 1 suspension test cells. Our results show that a standardized disinfectant test for biofilm cells is a useful addition to the current standard tests.
The resistance of bacterial biofilms to physical and chemical agents is attributed in the literature to various interconnected processes. The limitation of mass transfer alters the growth rate, and physiological changes in the bacteria in the film also appear. The present work describes an approach to determination of the mechanisms involved in the resistance of bacteria to quaternary ammonium compounds (benzalkonium chloride) according to the C-chain lengths of those compounds. For Pseudomonas aeruginosa CIP A 22, the level of resistance of the bacteria in the biofilm relative to that of planktonic bacteria increased with the C-chain length. For cells within the biofilm, the exopolysaccharide induced a characteristic increase in surface hydrophilicity. However, this hydrophilicity was eliminated by simple resuspension and washing. The sensitivity to quaternary ammonium compounds was restored to over 90%. Staphylococcus aureus CIP 53 154 had a very high level of resistance when it was in the biofilm form. A characteristic of bacteria from the biofilm was a reduction in the percent hydrophobicity, but the essential point is that this hydrophobicity was retained after the biofilm bacteria were resuspended and washed. The recovery of sensitivity was thus only partial. These results indicate that the factors involved in biofilm resistance to quaternary ammonium compounds vary according to the bacterial modifications induced by the formation of a biofilm. In the case of P. aeruginosa, we have underlined the involvement of the exopolysaccharide and particularly the three-dimensional structure (water channels). In the case of S. aureus, the role of the three-dimensional structure is limited and drastic physiological changes in the biofilm cells are more highly implicated in resistance.
Plaster of Paris (POP) bandages are extensively used for splinting and casting injured or surgically repaired body parts. Allergic contact dermatitis caused by POP has been reported only rarely in the medical literature. An 81-year-old woman developed multiple large, tense, haemorrhagic bullae on the palm, and an acute vesicular eczematous eruption on the forearm, after the application of a POP splint. Subsequent patch testing revealed positive reactions to both the POP bandage used and to benzalkonium chloride, a component of the POP formulation. Patch tests to two other POP products without benzalkonium chloride were negative. These results confirm those of previous studies which have implicated the quaternary ammonium compound benzalkonium chloride as the allergen responsible for POP-induced allergic contact dermatitis.
A highly reproducible and specific method for the analysis of the quaternary ammonium compound, benzalkonium chloride, in effluents from European hospitals is presented. Benzalkonium chloride was extracted with end-capped RP-18 solid-phase cartridges and was selectively eluted. The resulting solution was analyzed by high-performance liquid chromatography (HPLC). After elution from the analytical column of the HPLC system, 9,10-dimethoxyanthracene-2-sulfonate was added continuously as a fluorescence marker, forming a hydrophobic ion-pair with benzalkonium chloride. The ion-pair was analyzed by fluorescence detection. The method was applied to highly complex effluent samples from different sized European hospitals. The measured concentrations were between 0.05 and 6.03 mg/l. The amounts emitted per bed and year were 4.5-362 g and did not correlate with the size of the hospital. The total amounts were 2.6-909 kg/year.
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.
Resistant cells of Pseudomonas aeruginosa and a waterborne Pseudomonas sp. (strain Z-R) were able to multiply in nitrogen-free minimal salts solution containing various concentrations of commercially prepared, ammonium acetate-buffered benzalkonium chloride (CBC), a potent antimicrobial agent. As the CBC concentration increased, growth increased until a point was reached at which the extent of growth leveled off or was completely depressed. Minimal salts solutions of pure benzalkonium chloride (PBC) containing no ammonium acetate did not support bacterial growth. When ammonium acetate was added to PBC solutions in the same concentrations found in CBC solutions, growth patterns developed that were comparable to those found with CBC. Likewise, (NH(4))(2)SO(4) added to PBC solutions supported growth of both organisms. P. aeruginosa was initially resistant to CBC levels of 0.02% and it was adapted to tolerate levels as high as 0.36%. Strain Z-R was naturally resistant to 0.4% CBC. Since ammonium acetate, carried over by the CBC used in drug formulations and disinfectant solutions, has the potential to support the growth of resistant bacteria and thus make possible the risk of serious infection, it is suggested that regulations allowing the presence of ammonium acetate in CBC solution be reconsidered.
The retention behavior of the quaternary ammonium compounds benzalkonium chloride, cetylpyridinium chloride and dequalinium chloride on a 100 x 4.6 mm id cyanopropyl stationary phase column is reported as a function of organic modifier and ionic hydrophobic mobile phase additive concentrations. Optimum liquid chromatographic mobile phases using different mobile phase additives are reported which are suitable for the determination of cetylpyridinium chloride and dequalinium chloride in a variety of candy-based lozenge formulations. The quantitative aspects of assays based on the separation of active ingredients and formulation excipients were established. The generality of application of the assay methods was evaluated by determining the quaternary ammonium content of different lozenges and comparing the values obtained with the stated dose.
Publications on the subject of conjunctiva in 1991 have been reviewed. Clinical relevant topics have been stressed. In the field of conjunctival affections caused by microorganisms a spectrum of bilateral squamous conjunctival tumors associated with human papillomavirus type 16 were first documented. Chlamydial antibodies cause proliferation of lymphocytes. The peripheral lymphocyte proliferative response to whole chlamydial elementary bodies seems to have a strong correlation between the responses to the Chlamydia trachomatis serotypes B and L1. In the field of impression cytology of the conjunctiva the topographical distribution of ocular surface cells was described. In patients with glaucoma using long-term topical medication, there seem to be significant degrees of conjunctival metaplasia associated with the number of glaucoma medications. These changes in the conjunctival surface may be related to the preservatives in the preparations (benzalkonium compounds). An ultrastructural defect in conjunctiva in recessive dystrophic epidermolysis bullosa may increase the susceptibility of the conjunctiva to minor mechanical trauma. Thus resulting in the bullous and cicatrical changes seen clinically.
The control of industrial products for minimization of their impact on the environment and human health requires the development of specific analysis methods. Information provided by these methods about toxic components, by-products, and other derivatives may also be useful to reduce the possible impact of industrial products. The studied compound in this paper, triethylbenzylammonium chloride (TEBA), is mainly used in industrial synthesis. This quaternary compound and its residual products coming from quaternization reaction (benzyl chloride, benzaldehyde, and benzyl alcohol) are analyzed by HPLC. The separation is based on control of the silanophilic contribution to TEBA retention because of the quaternary nature of this compound. The effect of the three buffers (sodium acetate, ammonium acetate, and sodium formate) and their concentrations in the chromatographic behavior of the quaternary compound is examined. The buffer cation and anion regulate TEBA retention. Also, the concentration of the quaternary compound is another parameter that had influence in some aspects of its chromatographic behavior (e.g., retention and symmetry). The proposed method is applied to TEBA synthesis along, with the formation and removal of impurities with the results compared with those obtained for the quaternary compound benzalkonium chloride.
The complete nucleotide sequence of the 2.8 kb plasmid pST827 involved in resistance to the quaternary ammonium compound (QAC) benzalkonium chloride in meat-associated staphylococci was determined. An open reading frame (ORF) similar to the QAC resistance genes qacC, ebr and smr previously reported from clinical staphylococcal strains was identified (qacC'). In addition an ORF coding for a protein (Rep827) showing extensive homology to reported replication proteins of Gram-positive organisms was found. The occurrence of known QAC resistance gene (qacA-C) among staphylococcal strains isolated from food processing plants was studied by hybridization analysis. Of 191 isolates, 25 were resistant to benzalkonium chloride. Five of these gave no hybridization signals to probes specific for qacA-C. Further hybridization analysis indicated that pST827 or closely related plasmids are widespread among QAC-resistant staphylococcal strains. The finding of resistant staphylococci in different areas of the food processing industry indicates that QAC resistance is a potential problem in the food processing industry.
We examined 223 nurses from the Lódź region, referred to the Nofer Institute of Occupational Medicine in 1995-99 because of suspected occupational dermatoses. The diagnosis of contact allergy was based on the positive results of patch tests, and immediate allergy to common allergens and latex on the results of prick tests, as well as on the determinations of specific IgE antibodies. Contact allergy was diagnosed in 66.4% of nurses. The most frequent sensitisers were quaternary ammonium compounds (benzalkonium) (23.8%), nickel (21.5%) and formaldehyde (20.6%); allergy was somewhat less frequently caused by thimerosal (14.3%), fragrances (12.1%), glutaraldehyde (10.8%), cobalt (9.9%), thiurams (6.7%) or glyoxal (4.9%). Allergy to rubber was diagnosed in 40 patients (17.9%), including 25 cases of immediate allergy to latex, 8 cases of contact dermatitis from thiuram rubber curing accelerators, and 7 cases of mixed allergy. It has been concluded that the contact with disinfectants (40.8% of allergic nurses), metals (30.9%) and rubber (17.9%) was the most frequent source of allergy in this group of medical personnel.
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