Effect of subinhibitory exposure to quaternary ammonium compounds on the ciprofloxacin susceptibility of Escherichia coli strains in animal husbandry.

BACKGROUND: Quaternary ammonium compound based disinfectants are commonly used in pig and poultry husbandry to maintain farm hygiene. However, studies have shown that subinhibitory concentrations of these disinfectants may increase antibiotic resistance. Investigation of antibiotic susceptibility is usually assessed via the microbroth dilution method, although this conventional culture-based technique only provides information on the bacteriostatic activity of an antimicrobial agent. Therefore, experiments were performed to investigate the effect of prior benzalkonium chloride (BKC) exposure on the viability of subsequent ciprofloxacin (CIP) treated Escherichia coli. RESULTS: Following CIP treatment, bacterial cell counts were significantly higher after exposure to a subinhibitory BKC concentration than without BKC exposure. The flow cytometric results suggested a BKC-dependent onset of membrane damage and loss of membrane potential. CONCLUSION: Our results indicate a lower bactericidal effect of CIP treatment on BKC-exposed E. coli isolates compared to unexposed E. coli isolates.

Industrial, Biocide, and Cosmetic Chemical Inducers of Cholestasis.

A frequent side effect of many drugs includes the occurrence of cholestatic liver toxicity. Over the past couple of decades, drug-induced cholestasis has gained considerable attention, resulting in a plethora of data regarding its prevalence and mechanistic basis. Likewise, several food additives and dietary supplements have been reported to cause cholestatic liver insults in the past few years. The induction of cholestatic hepatotoxicity by other types of chemicals, in particular synthetic compounds, such as industrial chemicals, biocides, and cosmetic ingredients, has been much less documented. Such information can be found in occasional clinical case reports of accidental intake or suicide attempts as well as in basic and translational study reports on mechanisms or testing of new therapeutics in cholestatic animal models. This paper focuses on such nonpharmaceutical and nondietary synthetic chemical inducers of cholestatic liver injury, in particular alpha-naphthylisocyanate, 3,5-diethoxycarbonyl-1,4-dihydrocollidine, methylenedianiline, paraquat, tartrazine, triclosan, 2-octynoic acid, and 2-nonynoic acid. Most of these cholestatic compounds act by similar mechanisms. This could open perspectives for the prediction of cholestatic potential of chemicals.

Direct and Indirect Effect of Chlorhexidine on Survival of Stem Cells from the Apical Papilla and Its Neutralization.

INTRODUCTION: Several irrigants have been used for disinfection in regenerative endodontic procedures including chlorhexidine (CHX). In this context, the antibacterial properties of disinfectants are mainly in focus of research even though they may have an undesirable impact on the fate of stem cells. In this study, we hypothesized that CHX has both a direct effect when applied to stem cells of the apical papilla (SCAPs) and an indirect effect when SCAPs are exposed to dentin previously conditioned with CHX. METHODS: Cell toxicity was evaluated in vitro using the CellTox green fluorescence assay (Promega, Madison, WI) and CellTiter-Glo (Promega) after SCAPs were exposed directly to a dynamic concentration range of CHX; apical papilla explant cultures were stained with ApopTag (Merck Millipore, Billerica, MA) after culture with CHX. Furthermore, standardized slabs from human dentin were treated with CHX and consecutively rinsed in EDTA, L-α-lecithin (Sigma-Aldrich, St Louis, MO), or L-α-lecithin followed by EDTA. After that, SCAPs were cultured on the slabs for 5 days, and cellular viability was determined (indirect effect). Data were treated nonparametrically and analyzed using the Krukal-Wallis test (P ≤ .05). RESULTS: Direct exposure of SCAPs to CHX highly affected cell viability at concentrations above 10-3%, whereas lower concentrations had no adverse effect. During the initial 60 minutes, concentrations of 10-2% CHX or higher resulted in early pronounced toxicity with a maximum effect within 15 minutes after exposure. Likewise, CHX-conditioned dentin slabs were detrimental to SCAP survival; however, the deleterious effects were completely reversed by neutralization with L-α-lecithin. CONCLUSIONS: Chlorhexidine is toxic to SCAPs when applied directly or indirectly via conditioned dentin. If applied for a short time and neutralized by L-α-lecithin, it can be a gentle and cell-preserving disinfectant before endodontic regeneration.

Prospects for harnessing biocide resistance for bioremediation and detoxification.

Prokaryotes in natural environments respond rapidly to high concentrations of chemicals and physical stresses. Exposure to anthropogenic toxic substances-such as oil, chlorinated solvents, or antibiotics-favors the evolution of resistant phenotypes, some of which can use contaminants as an exclusive carbon source or as electron donors and acceptors. Microorganisms similarly adapt to extreme pH, metal, or osmotic stress. The metabolic plasticity of prokaryotes can thus be harnessed for bioremediation and can be exploited in a variety of ways, ranging from stimulated natural attenuation to bioaugmentation and from wastewater treatment to habitat restoration.

Chlorhexidine: a new latex?

The rate of chlorhexidine (CHX) allergy is increasing. Anaphylaxis is common but mild reactions often go unnoticed. Diagnosis is easy to miss, but presentation can be severe and can occur at any time during a procedure. Hospitals must have management plan for patients who are allergic to CHX.

Chemoprevention in gastrointestinal physiology and disease. Natural products and microbiome.

The human intestinal tract harbors a complex ecosystem of commensal bacteria that play a fundamental role in the well-being of their host. There is a general consensus that diet rich in plant-based foods has many advantages in relation to the health and well-being of an individual. In adults, diets that have a high proportion of fruit and vegetables and a low consumption of meat are associated with a highly diverse microbiota and are defined by a greater abundance of Prevotella compared with Bacteroides, whereas the reverse is associated with a diet that contains a low proportion of plant-based foods. In a philosophical term, our consumption of processed foods, widespread use of antibiotics and disinfectants, and our modern lifestyle may have forever altered our ancient gut microbiome. We may never be able to identify or restore our microbiomes to their ancestral state, but dietary modulation to manipulate specific gut microbial species or groups of species may offer new therapeutic approaches to conditions that are prevalent in modern society, such as functional gastrointestinal disorders, obesity, and age-related nutritional deficiency. We believe that this will become an increasingly important area of health research.

Ozone inactivation of norovirus surrogates on fresh produce.

Preharvest contamination of produce by foodborne viruses can occur through a variety of agents, including animal feces/manures, soil, irrigation water, animals, and human handling. Problems of contamination are magnified by potential countrywide distribution. Postharvest processing of produce can involve spraying, washing, or immersion into water with disinfectants; however, disinfectants, including chlorine, have varying effects on viruses and harmful by-products pose a concern. The use of ozone as a disinfectant in produce washes has shown great promise for bacterial pathogens, but limited research exists on its efficacy on viruses. This study compares ozone inactivation of human norovirus surrogates (feline calicivirus [FCV] and murine norovirus [MNV]) on produce (green onions and lettuce) and in sterile water. Green onions and lettuce inoculated with FCV or MNV were treated with ozone (6.25 ppm) for 0.5- to 10-min time intervals. Infectivity was determined by 50% tissue culture infectious dose (TCID(50)) and plaque assay for FCV and MNV, respectively. After 5 min of ozone treatment, >6 log TCID(50)/ml of FCV was inactivated in water and ∼2-log TCID(50)/ml on lettuce and green onions. MNV inoculated onto green onions and lettuce showed a >2-log reduction after 1 min of ozone treatment. The food matrix played the largest role in protection against ozone inactivation. These results indicate that ozone is an alternative method to reduce viral contamination on the surface of fresh produce.

Impact of a rub and rinse on solution-induced corneal staining.

PURPOSE: To investigate whether the inclusion of a rub and rinse step before contact lens disinfection has an impact on solution-induced corneal staining. METHODS: This was a prospective, double-masked, single investigator study. Twenty participants were recruited for two visits, where balafilcon-A lenses were worn bilaterally for 2 h. Each pair of lenses was prepared using two different methodologies. The "control" lens was transferred from the blister pack directly into a storage case containing polyhexamethylene biguanide-based lens care solution. The contralateral "test" lens was rubbed and simultaneously rinsed using the same polyhexamethylene biguanide-based care solution, for either 60 s (visit 1) or 20 s (visit 2). Both lenses were then soaked in the solution overnight. After baseline corneal staining assessments, the lenses were inserted following a randomized contralateral model. After 2 h, lenses were removed, corneal staining was regraded, and comfort scores were obtained. RESULTS: Rubbed and rinsed test lenses induced significantly less corneal staining than control lenses for all participants during visit 1 (mean ± SD: 516 ± 843 vs. 2170 ± 902; p < 0.001) and visit 2 (522 ± 417 vs. 2091 ± 965; p < 0.001). There was no significant difference between the test lenses during visits 1 and 2 (p = 0.72) or controls (p = 0.50). Comfort scores did not differ between eyes (p > 0.05). CONCLUSIONS: Corneal staining induced after 2 h of lens wear with the combination of balafilcon-A and polyhexamethylene biguanide-based lens care solution can be significantly reduced by including a rub and rinse step before overnight soaking. Further work is required to establish the longevity of this effect during the monthly wearing cycle.

[The statement of Polish Gynaecologic Society experts concerning drinking water consumption in women in reproductive age, pregnancy and breast feeding]. / Stanowisko Zespolu Ekspertów Polskiego Towarzystwa Ginekologicznego dotyczaqce spozycia wody pitnej przez kobiety w okresie rozrodczym, ciezarne oraz karmiace piersia.

Water is a substance essential for life. It creates the environment of our body, keeps it's homeostasis, enables every biochemical reaction and metabolic processes in human organism. Maternal hydratation is essential for homeostasis of two organisms and drinking water influences the amniotic fluid volume, fetal well-being and removes toxic metabolic products. The chemical contaminants of drinking water and products of it's chlorination and ozonization could be responsible for spontaneous abortion, birth defects and perinatal complications. Therefore it is recommended to drink natural mineral water for women in reproductive age.

Sporicidal activity of two disinfectants against Clostridium difficile spores.

The sporicidal activity of an odour-free peracetic acid-based disinfectant (Wofasteril) and a widely-used dichloroisocyanurate preparation (Chlor-clean) was assessed against spores of the hyper-virulent strain of Clostridium difficile (ribotype 027), in the presence and absence of organic matter. In environmentally clean conditions, dichloroisocyanurate achieved a >3 log10 reduction in 3 minutes, but a minimum contact time of 9 minutes was required to reduce the viable spore load to below detection levels. Peracetic acid achieved a >3 log10 reduction in 30 minutes and was overall significantly less effective (P<0.05). However, in the presence of organic matter - which reflects the true clinical environment - there was no significant difference between the sporicidal activity of dichloroisocyanurate and peracetic acid over a 60-minute period (P=0.188). Given the greater occupational health hazards generally associated with chlorine-releasing agents, odour-free peracetic acid-based disinfectants may offer a suitable alternative for environmental disinfection.

Chemical colitis.

Chemical colitis can occur as a result of accidental contamination of endoscopes or by intentional or accidental administration of enemas containing various chemicals. Most cases have occurred after accidental contamination of endoscopes with glutaraldehyde and/or hydrogen peroxide. There have been multiple case reports of chemical colitis resulting from unintentional administration of caustic chemicals. Intentional administration of corrosive enemas has been implicated in sexual practices, bowel cleansing, or in suicide attempts. Patients present with nonspecific symptoms including abdominal pain, rectal bleeding, and/or diarrhea. As chemical colitis remains rare, the literature consists of scattered case reports and small series. Agents implicated in chemical colitis that are covered in this review include alcohol, radiocontrast agents, glutaraldehyde, formalin, ergotamine, hydrofluoric acid, sulfuric acid, acetic acid, ammonia, soap, sodium hydroxide, hydrogen peroxide, herbal medicines, chloro-m-xylenol, and potassium permanganate. Clinical, endoscopic, and histologic features are outlined for each agent in addition to the existing literature. Given the nonspecific presentation of many cases of chemically induced colitis, the diagnosis can be challenging if the pertinent history is not obtained. Most patients demonstrate the resolution of chemical-induced colitis after conservative or medical therapy. Depending on the depth and extent of injury, patients rarely require colectomy for ischemic colitis and/or peritonitis. Other postingestion complications include colonic strictures and rectovaginal fistulae. The benefits of medical therapy compared with conservative therapy are not known, as comparative clinical management trials have not been performed.

Efficacy of potato seeds disinfection products to control Erwinia spp.

Erwinia spp. provokes soft rot on potato tubers during storage. No disinfection products are available on the market in the European Union to control these bacteria. We tested 3 products presented as good candidates to cure potato tubers from bacterial diseases. First, Anthium 500 (Du Pont de Nemours) a product based on chlorine dioxyde, then Phostrol (Nufarm) with phosphoric acid as a.i. and finally Solucuivre (Proval), a copper based product. We firstly managed disinfection trials: high Erwinia contaminated potato seed samples were treated by immersion and were then incubated, we observed the percentage of tubers rotting. Secondly, we managed protection trials: protected healthy tubers were incubated during 23 days in contact with rotting tubers. We evaluated weight loss after symptoms development. No tested product was effective to control Erwinia spp. on seed tubers in our trials conditions. Furthermore, we observed more rot development after Phostrol and Solucuivre application. We suppose that the product couldn't reach the latent bacteria and weakened the tubers. No protection effect was observed.

Exposure to carcinogens and mortality in a cohort of restoration workers of water-damaged library materials following the River Arno flooding in Florence, 4 November 1966.

BACKGROUND: In Florence, Italy, the Arno River overflowed on 4 November 1966 and the rare library collections of the National Central Library in Florence (FNCL) were flooded. A Restoration Centre was immediately set up. For book restoration many toxic chemicals were used, such as chlorinated solvents, ethylene oxide (EtO), formaldehyde, petroleum distillates, and pesticides. The study's aims were: (I) to document the restoration process, (II) to identify the potential chemical exposures, (III) to evaluate the mortality experience of restorers. METHODS: A small cohort of 168 workers was identified. The restorers were employed in the FNCL's Restoration Centre during the years 1967-1976. We excluded 9 subjects from the analysis because no working period data were available. Mortality from all causes, from all cancers, and from cancers of specific sites was compared with that of the Italian general population. Standardized Mortality Rates (SMRs) and their 95% confidence intervals were estimated. RESULTS: Restorers were exposed to relatively low levels of several carcinogens. A non-significant excess of cancer mortality was found. Significant increases in brain neoplasm among men and in uterine cancer among women were found, CONCLUSIONS: The small cohort size hampers interpretation of the results. Larger epidemiology studies on library material restorers are needed in order to evaluate risks in this activity. Recommendations to improve future studies are given.

Comparison of quantitative light-induced fluorescence (QLF) and digital imaging applied for the detection and quantification of staining and stain removal on teeth.

OBJECTIVES: This study compares the use of QLF with digital imaging in the detection and quantification of the development and removal of stain on teeth. METHODS: Two experimental phases, tooth staining and tooth whitening, conducted in vitro on labial 12 mm(2) enamel windows made on ten extracted bovine teeth, developed stains in 6-min cycles (2 min in each solution) using artificial saliva, chlorhexidine and tea solutions and removed them using sodium perborate monohydrate in 2-min cycle monitored at the end of each cycle with QLF (Inspektor Research Systems, NL) and digital photography (Fuji, Japan). The stain values were quantified as DeltaQ derived from QLF and DeltaE from digital imaging. This was observed by the two methods correlated with Pearson correlation coefficient (r). Regression equations (R(2)) were also obtained. RESULTS: For both staining and stain removal there was a statistically significant (p<0.01) reverse correlation between DeltaQ values for QLF (r=-0.924, R(2)=85.4%) and DeltaE values for digital imaging (r=-0.994, R(2)=98.8%), respectively. CONCLUSION: QLF showed a high correlation with digital imaging as a technique for detecting and monitoring tooth stains and tooth whitening in vitro. The potential for QLF with further development as a tool for monitoring staining and whitening of teeth may be possible in vivo in addition to the diagnostic ability for caries detection.

Cosmetic allergy: incidence, diagnosis, and management.

A recent epidemiologic survey in the UK revealed that 23% of women and 13.8% of men experience some sort of adverse reaction to a personal care product over the course of a year. Although most of these reactions may be due to subjective sensory irritation, various studies reveal that up to 10% of dermatologic patients who are patch tested are allergic to cosmetic products or their constituent ingredients. Causative products include deodorants and perfumes, skin care products, hair care products, and nail cosmetics. Allergic contact dermatitis mainly results from fragrance chemicals and preservatives. Recent work has suggested that additional fragrance chemicals may need to be tested in order to identify those patients 'missed' by the current fragrance mix; in particular, hydroxy-isohexyl-3-cyclohexene carboxaldehyde (HMPPC Lyral) has been singled out as an important sensitizing agent. The increased usage of natural fragrances and botanic extracts can also cause problems in their own right or through co-reactivity. The preservative methyldibromo glutaronitrile has also been recognized as an increasingly important sensitizer in Europe, which has led to the recent recommendation that it should be prohibited from 'leave-on' products until information on 'safe' consumer levels becomes available. Other emerging allergens include UV filters, tosylamide/formaldehyde resin, and nail acrylates. The diagnosis of cosmetic allergy should be confirmed with patch testing, including testing of 'whole' products, when necessary, and repeat open application tests can be used to confirm the relevance of reactions in cases of doubt.

Neurotoxicity produced by dibromoacetic acid in drinking water of rats.

An evaluation of potential adverse human health effects of disinfection byproducts requires study of both cancer and noncancer endpoints; however, no studies have evaluated the neurotoxic potential of a common haloacetic acid, dibromoacetic acid (DBA). This study characterized the neurotoxicity of DBA during 6-month exposure in the drinking water of rats. Adolescent male and female Fischer 344 rats were administered DBA at 0, 0.2, 0.6, and 1.5 g/l. On a mg/kg/day basis, the consumed dosages decreased greatly over the exposure period, with average intakes of 0, 20, 72, and 161 mg/kg/day. Weight gain was depressed in the high-concentration group, and concentration-related diarrhea and hair loss were observed early in exposure. Testing with a functional observational battery and motor activity took place before dosing and at 1, 2, 4, and 6 months. DBA produced concentration-related neuromuscular toxicity (mid and high concentrations) characterized by limb weakness, mild gait abnormalities, and hypotonia, as well as sensorimotor depression (all concentrations), with decreased responses to a tail-pinch and click. Other signs of toxicity at the highest concentration included decreased activity and chest clasping. Neurotoxicity was evident as early as one month, but did not progress with continued exposure. The major neuropathological finding was degeneration of spinal cord nerve fibers (mid and high concentrations). Cellular vacuolization in spinal cord gray matter (mostly) and in white matter (occasionally) tracts was also observed. No treatment-related changes were seen in brain, eyes, peripheral nerves, or peripheral ganglia. The lowest-observable effect level for neurobehavioral changes was 20 mg/kg/day (produced by 0.2 g/l, lowest concentration tested), whereas this dosage was a no-effect level for neuropathological changes. These studies suggest that neurotoxicity should be considered in the overall hazard evaluation of haloacetic acids.

Genotoxicity of surface water treated with different disinfectants using in situ plant tests.

Disinfection of surface drinking water, in particular water chlorination, results in many by-products with potential genotoxic and/or carcinogenic activity. In the present study, we evaluated the genotoxicity of surface water after treatment with different disinfectants by means of in situ plant genotoxicity assays (micronucleus and chromosomal aberration tests) which can detect both clastogenic and aneugenic effects. The study was carried out at a pilot plant using lake water after sedimentation and filtration. This water supplied four stainless steel basins: three basins were disinfected with sodium hypochlorite, chlorine dioxide, and peracetic acid and the fourth basin containing untreated lake water was used as a control. Plants were exposed in situ in the basins. The study was carried out using water collected in different seasons over a period of about 1 year in order to assess the treatments in different physical and chemical lake water conditions. The micronucleus test in root cells of Vicia faba (Vicia faba/MCN test) revealed genotoxicity in many samples of disinfected water. The micronucleus test in Tradescantia pollen cells and the chromosome aberration test in root cells of Allium cepa showed genotoxic effects only in some disinfected samples, but also revealed genotoxicity in raw water. The results of the study indicated that the Vicia faba/MCN test was the most sensitive plant assay for disinfected water and that peracetic acid disinfection produced similar or lower genotoxicity than sodium hypochlorite or chlorine dioxide treatment.