Endoscope sampling and culturing methods.

BACKGROUND: Contamination rates reported in the literature for patient-ready flexible endoscopes vary from 0.4% to 49%. Unfortunately, the comparison and interpretation of these results is almost impossible since several factors including sampling and culturing methods, target levels for contamination, or definition of indicator micro-organisms vary widely from one study to the other. AIM: To compare the efficacy of six duodenoscope sampling and culturing methods by means of extraction efficacy comparison, while at the same time identifying key parameters that provide optimal microbial recovery. METHODS: The duodenoscope sample extraction efficacy of each method was assessed using the repetitive recovery method described in ISO 11737-1: 2018. FINDINGS: Mean overall bioburden extraction efficacy varied from 1% for the Australian method to 39% for the French one. The lowest endoscope sample extraction efficacy was associated with the absence of any neutralizer, friction, or tensioactive agent, and when only a small portion of the sampling solution collected was inoculated on to culture media. The efficacy of the sampling and culturing methods also varied according to the nature of micro-organisms present in the endoscope, and the time between sampling and culturing. CONCLUSION: This study supports the need for a harmonized and standardized sampling and culturing method for flexible endoscopes.

Feeding predictability as a cognitive enrichment protects brain function and physiological status in rainbow trout: a multidisciplinary approach to assess fish welfare.

Cognitive enrichment is a promising but understudied type of environmental enrichment that aims to stimulate the cognitive abilities of animals by providing them with more opportunities to interact with (namely, to predict events than can occur) and to control their environment. In a previous study, we highlighted that farmed rainbow trout can predict daily feedings after two weeks of conditioning, the highest conditioned response being elicited by the combination of both temporal and signalled predictability. In the present study, we tested the feeding predictability that elicited the highest conditioned response in rainbow trout (both temporal and signalled by bubbles, BUBBLE + TIME treatment) as a cognitive enrichment strategy to improve their welfare. We thus analysed the long-term effects of this feeding predictability condition as compared with an unpredictable feeding condition (RANDOM treatment) on the welfare of rainbow trout, including the markers in the modulation of brain function, through a multidisciplinary approach. To reveal the brain regulatory pathways and networks involved in the long-term effects of feeding predictability, we measured gene markers of cerebral activity and plasticity, neurotransmitter pathways and physiological status of fish (oxidative stress, inflammatory status, cell type and stress status). After almost three months under these predictability conditions of feeding, we found clear evidence of improved welfare in fish from BUBBLE + TIME treatment. Feeding predictability allowed for a food anticipatory activity and resulted in fewer aggressive behaviours, burst of accelerations, and jumps before mealtime. BUBBLE + TIME fish were also less active between meals, which is in line with the observed decreased expression of transcripts related to the dopaminergic system. BUBBLE + TIME fish tented to present fewer eroded dorsal fin and infections to the pathogen Flavobacterium psychrophilum. Decreased expression of most of the studied mRNA involved in oxidative stress and immune responses confirm these tendencies else suggesting a strong role of feeding predictability on fish health status and that RANDOM fish may have undergone chronic stress. Fish emotional reactivity while isolated in a novel-tank as measured by fear behaviour and plasma cortisol levels were similar between the two treatments, as well as fish weight and size. To conclude, signalled combined with temporal predictability of feeding appears to be a promising approach of cognitive enrichment to protect brain function via the physiological status of farmed rainbow trout in the long term.

Endoscope drying/storage cabinet: interest and efficacy.

Inadequate drying of endoscope channels is a possible cause of microbial proliferation during storage. This risk could be reduced by any procedure or process used to dry endoscope channels and control storage conditions. The efficacy of a drying and storage cabinet (Hysis Medical) was tested on three different endoscopes: a colonoscope (Olympus); duodenoscope (Fujinon) and an enteroscope (Pentax), all of which had been artificially contaminated with a suspension of Pseudomonas aeruginosa CIP 103467. Changes to the residual internal contamination level of these endoscopes when stored inside or outside the drying cabinet for 12, 24, 48 or 72 h were compared. When stored in the drying and storage cabinet, microbial contamination levels on endoscopes were lower than the number of bacteria initially introduced and could decrease considerably thereafter. For endoscopes stored outside the drying storage cabinet, microbial numbers were stable or even increased. These data demonstrate the advantages of such endoscope drying/storage cabinets that limit the risk of bacterial proliferation in the internal channels of endoscopes during storage, and which ensure that the disinfection level reached at the end of the reprocessing procedure is maintained.

Comparison of the fixative properties of five disinfectant solutions.

Following a French circular published in 2001, the use of glutaraldehyde for the disinfection of reusable medical devices was abandoned in favour of non-fixative disinfectants such as peracetic-acid-based solutions. Data published regarding the fixative properties of alternative disinfectants remain contradictory. We compared the effect of repetitive treatments of polytetrafluoroethylene (PTFE) tubes, contaminated by a liquid medium inoculated with Pseudomonas aeruginosa, using five different disinfectant solutions: two peracetic acid solutions (with and without an activator), glutaraldehyde, ortho-phthaldehyde and succine dialdehyde. The results confirmed that repeated treatments of a PTFE tube with a 2% glutaraldehyde solution induce an important accumulation and/or fixation of protein, compared to peracetic-acid-based disinfectants, for which the accumulation and/or fixation of proteins remain low and vary from one formulation to another.

Incapacity and autonomy: striking a balance.

We want to take this opportunity to offer our perspective on some of the issues to which the Substitute Decisions Act, 1992, and the Consent to Treatment Act, 1992, represent a response. To a lesser extent, the provisions of the Advocacy Act, 1992, which governs the provision and role of advocates, will be considered. First, we hope to explain, perhaps a little more than can be done in Committee, or in the Legislature, the thinking that underlies some of the protective measures this legislation makes available to persons who are thought to be mentally incapable. Second, we provide some discussion of the problem of the criterion of mental capacity, and argue that where there is no strict criterion, it is important to ensure that individuals who are subjects of assessments of their mental capacity are protected by a balance of power in which they hold a prominent position. Third, we suggest that the lack of a strict criterion of capacity argues for a broad criterion for assessors.

Evaluation of a storage cabinet for heat-sensitive endoscopes in a clinical setting.

BACKGROUND: In most countries, endoscopes must be disinfected or fully reprocessed before the beginning of each session, even if they were cleaned and disinfected after their last use. Several storage cabinets for heat-sensitive endoscopes (SCHE) are commercially available. They are designed to maintain the microbiological quality of reprocessed endoscopes for a predefined period of time validated by the SCHE manufacturer. Use of an SCHE increases the acceptable storage time before it is necessary to re-disinfect the endoscope. AIM: To evaluate the efficacy of an SCHE (DSC8000, Soluscope, SAS Marseilles, France) in a clinical setting. METHOD: The microbiological quality of endoscopes was assessed after 72 h of storage in an SCHE (Group I), and compared with the microbiological quality of endoscopes stored for 72 h in a clean, dry, dedicated cupboard without morning disinfection (Group II) and the microbiological quality of endoscopes stored for 72 h in a clean, dry, dedicated cupboard with morning disinfection (Group III). Forty-one endoscopes in each group were sampled for microbiological quality. Endoscope contamination levels were analysed according to guidelines published by the National Technical Committee on Nosocomial Infection in 2007. FINDINGS/CONCLUSION: Use of an SCHE helps to maintain the microbiological quality of endoscopes, provided that staff members are well trained and all practices are framed by a proven quality assurance process.

Monitoring of maximum expiratory peak flow rates and histamine inhalation tests in the investigation of occupational asthma.

A 49 year old carpenter developed asthma after he was employed in a new workshop. Specific inhalation tests carried out in a laboratory with presswood sawdust and the different glues used at work were negative. Monitoring peak expiratory flow rates (PEFR) at work revealed a progressive fall on consecutive days with recovery after periods off-work. Histamine inhalation tests showed a definite increase in bronchial hyperexcitability after working periods. Monitoring of PEFR in conjunction with histamine inhalation tests can thus help in confirming occupational asthma.

Occupational asthma due to pepsin.

A 30-year-old atopic worker exposed to pepsin powder, herb, and pollen extracts at work developed an increase in asthmatic symptoms. Monitoring of peak expiratory flow rate revealed more important fluctuations at work. Skin prick tests yielded a large immediate reaction to pepsin. Specific inhalation challenges confirmed the diagnosis; an intense early response was documented after exposure to pepsin. The pepsin IgE RAST was positive and selectively inhibited by pepsin.

Occupational asthma due to azobisformamide.

Azobisformamide is a low molecular weight agent used in the plastic industry as a foaming product. Two subjects with a history of work-related asthma in association with exposure to azobisformamide underwent specific inhalation tests. One subject developed an isolated late asthmatic response, whereas in the other a dual reaction was observed.

Automatic washer disinfector for flexible endoscopes: a new evaluation process.

BACKGROUND AND STUDY AIMS: Many automatic washer disinfectors for flexible endoscopes have been marketed and offered as an alternative method of preventing infections, but they are frequently unsatisfactory. There is therefore clearly a need to test prototypes prior to marketing, following an evaluation process that is sufficiently reliable and rigorous to guarantee the efficacy of the decontamination processes. MATERIALS AND METHODS: The present study describes an experimental method based on the follow-up of the decontamination of a Tygon tube, the internal surface of which was contaminated by a bacterial biofilm. This method is proposed as a preliminary test for evaluating washer disinfectors. RESULTS: An analysis of the results obtained after technical modifications of the first prototype of the Fibro-Cleaner showed that complementary activities of each successive cycle phase allow a reduction in the number of adherent bacteria of more than 8 log per cm2 of support. With the three different biofilms tested (Escherichia coli, Pseudomonas aeruginosa mucoid and Staphylococcus aureus), no microorganisms were recovered from the support at the end of the decontamination process. CONCLUSIONS: The experimental protocol suggested here seems to be well suited for assessing washer disinfectors during the development phase of the prototype, as well as for comparative studies.

Reference values of the provocative concentrations of methacholine that cause 6% and 20% changes in forced expiratory volume in one second in a normal population.

The provocative concentrations of inhaled methacholine that cause 6% (PC6) and 20% (PC20) falls in forced expiratory volume in one second (FEV1) were assessed in a population of 100 nonsmoking persons, equally distributed for sex, who ranged uniformly from 20 to 60 yr of age. These subjects had no respiratory symptoms, rhinitis, atopic history, or familial history of asthma. Single twofold dilutions of methacholine from 2 to 128 mg/ml were used; 81 and 34 subjects, respectively, showed PC6 and PC20 values less than 128 mg/ml. Eight subjects had PC20 values less than 16 mg/ml. In these subjects, the test had a good reproducibility (r = 0.92) when we repeated it, and serial measurements of peak expiratory flow rates did not suggest asthma. The fact that PC6 was related, although loosely, to baseline FEV, FEV/FVC, and forced expiratory flow during the middle half of the FVC (FEF) and that 4 of the 8 subjects with PC20 values less than 16 mg/ml had lower values of FEF might suggest that responsiveness to methacholine is partially linked with baseline airway caliber.

Effect of sodium cromoglycate on histamine inhalation tests.

Sixteen adult asthmatic subjects in a clinical steady state were included in the study. On day 1, after baseline assessment of spirometry (FEV1, FEV1/FVC, FEF25-75), they underwent three to four consecutive inhalation tests using twofold increasing doses of histamine to measure the provocative concentration causing a fall in FEV1 of 20% (PC20). Baseline FEV1 was back to +/- 5% of the initial assessment before each histamine inhalation test (HIT). On days 2, 3, and 4, after baseline spirometry which confirmed that FEV1 was within 10% of initial day 1 assessment, placebo-lactose (P) or 40 mg of sodium cromoglycate (SCG) were nebulized in a double-blind randomized 4.3.1. two-treatment crossover study design. Ten minutes later, spirometry was repeated and followed by an HIT. Baseline spirometry was not significantly different on each day or after P and SCG. There was no statistical difference between the geometric means of the three or four PC20's done on day 1, indicating that there is no tachyphylaxis induced by repeated HIT. There was no statistical difference between mean PC20 after P (0.52 +/- 3.3 (SD) mg/ml), after SCG (0.50 +/- 3.2), and of the three to four HIT done on day 1 (0.40 +/- 3.6). We conclude that in asthmatic subjects SCG has no acute bronchodilator effect and does not alter the response to inhaled histamine.

Bronchial responsiveness to methacholine and effects of respiratory maneuvers.

Eight asthmatic and six normal subjects had methacholine chloride inhalation tests on two visits. On first assessment the provocative concentration causing a 20% fall in forced expiratory volume in 1 s (PC20FEV1) was measured. On the second visit the provocative concentration causing a 35% fall in specific lung conductance (PC35sGL) was obtained in addition to the PC20FEV1. Lung resistance was continuously monitored to evaluate the bronchomotor effect of FEV1 maneuver. Results of PC20FEV1 were within one single twofold concentration on the two visits. In all subjects but one PC35sGL was lower than PC20FEV1, and in 10 instances this difference was superior to a single twofold concentration. The bronchodilator effect of FEV1 maneuver was significantly although loosely related to base-line airway caliber and excitability. However, we were unable to show a significant relationship between the differences between PC20FEV1 and PC35sGL and this bronchodilator effect. This suggests that other factors may explain the greater sensitivity of PC35sGL compared with PC20FEV1.

Nonallergic bronchial hyperexcitability in chronic bronchitis.

The aim of this study was to assess responsiveness to inhaled histamine and methacholine using PC20, the concentration causing a 20% fall in forced expiratory volume in one second (FEV1) in 28 subjects with chronic bronchitis excluding asthma. Eighteen subjects had airway hyperexcitability, as demonstrated by a PC20 less than 16 mg/ml. The response to histamine and methacholine was not significantly different and the correlation coefficient was 0.75. Baseline airway caliber was related to the level of hyperexcitability, as 14 of 14 subjects with a FEV1 to forced vital capacity ratio less than 95% pred and/or a forced expiratory flow during the middle half of the FVC less than 80% pred, and only 4 of 10 subjects with normal spirometry, had a PC20 less than 16 mg/ml (x2 = 15.6, p less than 0.001). There was no correlation between blood or sputum eosinophilia, total IgE levels, or atopy and the level of airway hyperexcitability. Spontaneous daily variations of peak expiratory flow rates were significantly (t = 2.43, p less than 0.05) more pronounced in subjects with PC20 less than 16 mg/ml. We conclude that airway hyperexcitability assessed with PC20 is often present in chronic bronchitis and more often so in the presence of airway obstruction.

Slope of the dose-response curve to inhaled histamine and methacholine and PC20 in subjects with symptoms of airway hyperexcitability and in normal subjects.

Slopes of the dose-response curves to inhaled histamine or methacholine and PC20 were compared in 14 subjects with symptoms of bronchial hyperexcitability and in 10 normal subjects. Slopes were obtained by analyzing curves with 3 to 6 points by the least squares method. Only curves with satisfactory correlation coefficients corresponding to p values less than 0.05 were kept for analysis. Twelve of the 14 subjects with symptoms of bronchial hyperexcitability and 1 of the 10 normal subjects had slopes greater than 20 (percent change in FEV1/log histamine or methacholine concentration) (chi-square = 13.5, p less than 0.001). Eleven of the 14 subjects with symptoms of bronchial hyperexcitability and 1 of the 10 normal subjects had PC20 results less than or equal to 16 mg/ml (chi-square = 11.0, p less than 0.001). It is concluded that, using the method described in our study, slopes of the dose-response curve to inhaled histamine or methacholine are different in subjects with and without symptoms of bronchial hyperexcitability.

Interactions between biocide cationic agents and bacterial biofilms.

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.

Antimicrobial resistance of mesophilic Aeromonas spp. isolated from two European rivers.

The activity of 19 antibiotics and four antiseptics and/or disinfectants was studied against 138 non-redundant strains of Aeromonas spp. (104 Aeromonas caviae, 22 Aeromonas sobria and 12 Aeromonas hydrophila) isolated from two European rivers. Antibiotic resistance frequencies were: nalidixic acid, 59%; tetracycline, 14%; fosfomycin, 8%; tobramycin and cotrimoxazole, 7%; cefotaxime, 4%; chloramphenicol, 2%; gentamicin, 1%. Most of the nalidixic acid-resistant strains were susceptible to fluoroquinolones (54-98%). Antibiotic resistance rates varied according to the source of the strains. All Aeromonas spp. strains were killed by 50 ppm of chlorine, cetylpyridinium chloride and peracetic acid, and by 1600 ppm of glutaraldehyde.

Circadian variations of airway response to histamine in asthmatic subjects.

In 15 clinically stable asthmatic subjects, histamine inhalation challenges were carried out on six different days, at 8, 16 and 22 h, twice at each time. On each visit, baseline functional measurements including FEV1 and forced mid-expiratory flow rates (FEF25-75%) were followed by the assessment of the concentration of histamine causing a 20% fall in FEV1 (PC20). There was no significant difference in baseline lung function tests and PC20 for visits done either at the same or different times. The correlation coefficients of PC20 for the visits at 8, 16 and 22 h were 0.95, 0.88 and 0.78 respectively. The dispersion of results of PC20 was significantly (p less than 0.05) more pronounced at 22 h than at 8 h. The cosinor analysis which depicts biologic rhythms as sinusoidal curves [8] revealed that seven subjects had detectable diurnal rhythms with acrophases (time of least excitability) at 9.8, 10.0, 11.8, 15.3, 15.4, 22.2 and 23.1 h. In five and three of these seven subjects respectively, significant rhythms of FEV1 and FEF25-75% were also detected with similar acrophases.

Occupational asthma in snow crab-processing workers.

The prevalence of occupational asthma was studied in two snow crab-processing industries in operation since 1980. Before the 1982 season, all except 10 of the 313 employees were investigated by a questionnaire, prick skin tests with common allergens, crab n and crab-boiling water extracts, and spirometry. The diagnosis was confirmed in 46 (15.6%) workers (including 33 of 64 subjects with a history highly suggestive of occupational asthma in the previous seasons) by (1) specific inhalation challenges in 33 subjects (one immediate, nine dual, and 23 late asthmatic responses) and/or (2) a combination of monitoring of peak expiratory flow rates (n = 12) and significant changes in bronchial responsiveness to histamine (n = 16) as well as in spirometry (n = 18) after reappearance of symptoms on return to work. Positive skin tests to crab (p less than 0.001) and, to a lesser degree, smoking history (p = 0.03) but not atopy (p greater than 0.05) were related to the presence of occupational asthma. A high prevalence of rhinoconjunctivitis (35 of 46) and urticaria (16 of 46) was also documented in the affected individuals.

Pulmonary function tests and airway responsiveness to methacholine in chronic bronchiectasis of the adult.

Fifty adults with chronic bronchiectasis (mean duration since diagnosis: 25 +/- 16.4 years), excluding those cases secondary to tuberculosis or hypogammaglobulinemia, were investigated by a questionnaire, a chest radiograph and lung function tests. Of these, 29 with an FEV1 greater than 1.5 1 underwent methacholine inhalation tests. Fourty-three subjects and three subjects respectively showed an obstructive or a mixed obstructive and restrictive defect, only four having normal lung function tests. Sixty-nine percent of subjects tested had a provocative concentration of methacholine causing a 20% fall in FEV1 (PC20) less than 16 mg X ml-1. Subjects with daily sputum production had lower values of FEV1 and FEV1/forced vital capacity (FVC) compared to subjects with less than daily sputum. Subjects with clinical features of bronchial hyperexcitability had significantly lower baseline FEV1, vital capacity, and maximal mid-expiratory flow rate (FEF25-75). Subjects with lower PC20 values had significantly lower baseline FEV1, FEV1/FVC and FEF25-75. Finally, subjects with the greatest extent of radiological abnormalities had lower baseline FEV1, FEV1/FVC and diffusing capacity, and a higher residual volume. We conclude that chronic bronchiectasis is associated with significant changes in lung function tests and increased responsiveness to methacholine in the majority of affected individuals.