Epidemiology and genomics of a slow outbreak of methicillin-resistant Staphyloccus aureus (MRSA) in a neonatal intensive care unit: Successful chronic decolonization of MRSA-positive healthcare personnel.

OBJECTIVE: To describe the genomic analysis and epidemiologic response related to a slow and prolonged methicillin-resistant Staphylococcus aureus (MRSA) outbreak. DESIGN: Prospective observational study. SETTING: Neonatal intensive care unit (NICU). METHODS: We conducted an epidemiologic investigation of a NICU MRSA outbreak involving serial baby and staff screening to identify opportunities for decolonization. Whole-genome sequencing was performed on MRSA isolates. RESULTS: A NICU with excellent hand hygiene compliance and longstanding minimal healthcare-associated infections experienced an MRSA outbreak involving 15 babies and 6 healthcare personnel (HCP). In total, 12 cases occurred slowly over a 1-year period (mean, 30.7 days apart) followed by 3 additional cases 7 months later. Multiple progressive infection prevention interventions were implemented, including contact precautions and cohorting of MRSA-positive babies, hand hygiene observers, enhanced environmental cleaning, screening of babies and staff, and decolonization of carriers. Only decolonization of HCP found to be persistent carriers of MRSA was successful in stopping transmission and ending the outbreak. Genomic analyses identified bidirectional transmission between babies and HCP during the outbreak. CONCLUSIONS: In comparison to fast outbreaks, outbreaks that are "slow and sustained" may be more common to units with strong existing infection prevention practices such that a series of breaches have to align to result in a case. We identified a slow outbreak that persisted among staff and babies and was only stopped by identifying and decolonizing persistent MRSA carriage among staff. A repeated decolonization regimen was successful in allowing previously persistent carriers to safely continue work duties.

[Research of the cadmium intoxication effect on the model of vitamin-mineral deficiency in rats].

The article presents the results of the study aimed at confirmation of the effectiveness of the rats' adaptive potential reduction under conditions of cadmium salt toxic effects. The 65-days experiment was conducted in male and female Wistar rats. Animals were divided into 6 groups of 3 control and 3 experimental, 30 males and females in each. In total 360 rats were used in the experiment (180 females and 180 males). Rats of the 1st control group received a diet with optimal (75% of the standard semisyntethic diet content) dosage of vitamins B1, B2, B3, B6 and mineral substances, Fe3+ and Mg2+, the rats of the 2nd and the 3rd control group - diets with marginal (30% for males and 28% for females) and submarginal (19% for males and 18% for females) doses of essential micronutrients. Animals of the 1-3th experimental groups received Cd2+ on the background of optimal, marginal and submarginal providing of essential micronutrients. The hematological, biochemical and morphological parameters and the antioxidant status of rats have been studied. The obtained results allowed to identify patterns of cadmium toxic effect strengthen on the background of essential nutrients reducing (in the row from optimal to submarginal). These changes showed erythrocyte and platelet blood profiles, and a set of indicators of the antioxidant defense system and lipid peroxidation of blood and liver. Thus, the activity of erythrocyte antioxidant enzymes - glutathione reductase, glutathione peroxidase, catalase and superoxide dismutase in rats of the 1st experimental group were on average by 23% higher than in animals of the 1st control group, the rats of the 2nd and the 3rd experimental groups by 62 and 67% higher, respectively. The content of lipid peroxidation products in blood and liver of male and female rats showed a similar trend: an increase by 5% in the 1st experimental group by 9 and 25% in the 2nd and 3rd experimental groups respectively. Thus, the modification of the diets' vitamin-mineral composition may be used as a model of adaptive potential reduction in rats in the toxicological research of objects with unknown toxicity, in particular novel food products.

Evolution of the determinants of chronic liver disease in Quebec.

INTRODUCTION: Chronic liver diseases (CLDs) are a worldwide problem. Morbidity and mortality due to CLDs could be avoided or reduced by targeting the main risk factors, including obesity and alcohol use. METHODS: To describe the evolution of the key determinants of CLDs in Quebec, we studied the trends in obesity, alcohol use, viral hepatitis B and C, CLD mortality and hospitalization rates, and the liver cancer incidence rate between January 1, 1981, and December 31, 2009. RESULTS: We observed an increase in the obesity indicators among young men and in alcohol use among adolescent girls and middle-aged women. The overall hepatitis B and C incidence and CLD mortality rates are falling. However, liver cancer and mortality rates, especially among men and the elderly, are on the rise. CONCLUSION: These results highlight the importance of targeted public health interventions and of maintaining or improving access to care for CLDs.

TITLE: Évolution des déterminants des maladies chroniques du foie au Québec. INTRODUCTION: Les maladies chroniques du foie (MCF) constituent un problème mondial. La morbidité et la mortalité des MCF pourraient être évitées ou atténuées en agissant sur leurs principaux facteurs de risque, notamment l'obésité et la consommation d'alcool. MÉTHODOLOGIE: Afin de décrire l'évolution des principaux déterminants des MCF au Québec, nous avons étudié les tendances de l'obésité, de la consommation d'alcool, des hépatites virales B et C, de la mortalité et du taux d'hospitalisation des MCF ainsi que du taux d'incidence du cancer du foie entre le 1er janvier 1981 et le 31 décembre 2009. RÉSULTATS: Nous avons observé une augmentation des indicateurs de l'obésité chez les jeunes hommes et de la consommation d'alcool chez les adolescentes et chez les femmes d'âge moyen. Les taux d'incidence globale des hépatites B et C et de la mortalité par MCF sont en diminution. Cependant, les taux d'incidence du cancer du foie et de sa mortalité, surtout chez les hommes et les personnes âgées, sont à la hausse. CONCLUSION: Ces résultats soulignent l'importance des interventions de santé publique ciblées ainsi que le maintien ou l'amélioration de l'accès aux soins pour les MCF.

Spermatozoa and seminal plasma fatty acids as predictors of cryopreservation success.

There is a lack of information about the importance of fatty acid composition of the human sperm membranes and seminal plasma in the cryopreservation procedure. Our aims were to study the possible relationships between the fatty acid composition of human spermatozoa or seminal fluid before freezing, and the sperm quality, measured in terms of viability and motility, before and after freezing-thawing. A further objective of this study was to determine whether the antioxidant capacity (TAC) of the seminal plasma is related to fatty acid (FA) composition and to success of the cryopreservation process. Polyunsaturated fatty acids (PUFA), ω3 PUFAs and docosahexaenoic acid (DHA) in spermatozoa were significantly positively correlated with sperm viability and motility parameters before and after freezing. An inverse relationship was found for monounsaturated (MUFA), ratio ω6/ω3, ratio saturated saturated fatty acids/PUFA (SFA/PUFA) with the seminal parameters. Seminal plasma fatty acid composition was not related to viability. However, motility parameters before and after freezing were related to stearic acid (C18:0) and DHA. TAC in seminal plasma was directly related to PUFA, w3 and DHA. On the other hand, SFA, C22:0, C24:0 and MUFA in seminal plasma were inversely related to the antioxidant capacity. TAC was directly correlated with motion parameters after thawing, We described a significant correlation between the fatty acid composition of the human spermatozoa or seminal plasma and the sperm parameters of the samples after thawing. PUFA, W3 and specially DHA are directly correlated with sperm motility and viability after freezing/thawing, and MUFA was inversely correlated. This means that in the future the fatty acid composition could be used as a predictor of the capacity of cryopreservation. On the other hand, we could design further procedures to modify the lipid composition or/and antioxidant capacity of ejaculate to make it more resistant to the cryopreservation process.

Simultaneous determination of potassium and total fluoride in toothpastes using a SIA system with two potentiometric detectors.

A sequential injection analysis (SIA) system has been developed for the first time to quantify potassium and total fluoride in toothpastes and gels used to prevent both dentinal hypersensitivity and dental caries. To enable this simultaneous determination, potentiometric detection, using a conventional fluoride electrode and a tubular potassium selective electrode, formed by a PVC membrane containing valinomycin as ionophore, was carried out. A manifold that uses a three-way solenoid valve was designed. The former under binary sampling conditions, provides reproducible mixing ratios of two solutions. This fact facilitates that the system automatically generates, on-line, the calibration curves required by the analytical procedure. The calibration ranged from 1.0 x 10(-4) to 1.0 x 10(-3) mol L(-1) for both potassium and total fluoride determinations. The R.S.D. (11 readings) resulted to be less than 1.5% for both determinations. Off-line studies related to the dissolution of the solid samples, the transformation of monofluorophosphate in fluoride, the elimination of organic matrix interference onto the plastic membrane of the potassium electrode, and the selection of the most adequate TISAB solution for fluoride determination, were also considered. A sampling rate of 18 samples h(-1) for both determinations was attained, their precisions and accuracies being statistically indistinguishable from those achieved by atomic emission spectroscopy (for potassium determination) and by a conventional batch potentiometry (for total fluoride determination) adopted as reference techniques.

Seroprevalence of parvovirus B19 infection in daycare educators.

This study was undertaken to provide first-time estimates for the seroprevalence of parvovirus B19 infection among daycare educators in Montréal, Canada, and to identify factors associated with seropositivity. A cross-sectional design was used. Directors and educators from 81 daycare centres (DCCs) were surveyed about DCC and personal characteristics respectively, and serum samples from 477 female educators were tested for parvovirus B19 IgG antibodies. The seroprevalence of parvovirus B19 was 70%. Parvovirus B19 seropositivity was significantly associated with age and with working experience in DCCs, but the latter association was restricted to educators aged less than 40 years. In conclusion, working as a daycare educator appears to be associated with increased risk of acquiring parvovirus B19 infection, but this finding will require further investigation. Because of the large proportion of educators susceptible to acquiring parvovirus B19 infection, our findings also highlight the need for preventive measures.

Comparison of methods to analyse imprecise faecal coliform count data from environmental samples.

Imprecise values arise when bacterial colonies are too numerous to be counted or when no colonies grow at a specific dilution. Our objective was to show the usefulness of multiple imputation in analysing data containing imprecise values. We also indicate that interval censored regression, which is faster computationally in situations where it applies, can be used, providing similar estimates to imputation. We used bacteriological data from a large epidemiological study in daycare centres to illustrate this method and compared it to a standard method which uses single exact values for the imprecise data. The data consisted of numbers of FC on children's and educators' hands, from sandboxes and from playareas. In general, we found that multiple imputation and interval censored regression provided more conservative intervals than the standard method. The discrepancy in the results highlights both the importance of using a method that best captures the uncertainty in the data and how different conclusions might be drawn. This can be crucial for both researchers and those who are involved in formulating and regulating standards for bacteriological contamination.

Predictors of pretravel consultation in tourists from Quebec (Canada).

BACKGROUND: Although many tourists from Quebec (Canada) each year visit destinations at risk for infectious diseases, only a few of them seek travel health advice. To identify the determinants of travel health consultation, we conducted a study among Quebec's tourists visiting two popular sun destinations. METHODS: A conceptual model based on psychosocial determinants of human behavior was constructed. A cross-sectional survey was carried out, from January to April 1999, on two samples of travelers planning to visit Mexico and the Dominican Republic. One sample was composed of people who did not consult a travel clinic (cluster sampling in seven flights), and the other sample was one of clients of travel clinics (purposive selection of 13 specialized clinics located in Quebec). A 34-item self-administered bilingual questionnaire was distributed to travelers. Statistical analysis included a multivariate approach (logistic regression). RESULTS: A total of 2,242 travelers were surveyed (response rate in flight 75% and in clinics 99%). We present only results reported by French-speaking tourists: 1,152 who did not consult a travel clinic and were reached in flight, and 449 who were reached in clinics. Multivariate analyses indicated that travel agent recommendation was the most important predictor of consultation among travelers (OR 8.0, 95% CI 5.1-13), especially among those under 45 years of age and those who never sought pretravel consultation before (OR 21, 95% CI 11-41). Other important predictors were: traveling for the first time, traveling with children, previous consultation, perception about efficacy of immunization, risk perception, and information from travel agent, family doctor, and pharmacist. CONCLUSIONS: Despite its limitations, this study provides data that should help improve public health interventions aimed at encouraging travelers to get a pretravel consultation.

Comparison between two common methods for reporting cold and diarrhoea symptoms of children in daycare centre research.

BACKGROUND: The increasing number of children attending day care centres (DCCs) in industrialized countries has refocused attention on the occurrence of infections and infectious diseases in these settings. OBJECTIVE: To evaluate the agreement between two methods (parent method vs. educator method) for reporting the occurrence of respiratory and diarrhoeal infections. METHODS: Fifty-two DCCs in Quebec, Canada, participated. Both educators and parents were invited to fill in calendars on which they would indicate the occurrence of colds and diarrhoea. For the parents' method, parents were telephoned biweekly to record their calendar information. For the educators' method, educators returned their calendar pages monthly (following prompting by phone, when necessary). RESULTS: Three hundred and thirty-three parents of toddlers participated in the 15-month reporting period between September 1996 and November 1997. The average agreement between the two methods was low (13.5% for colds and 9.8% for diarrhoea). Overall estimates of the incidence rates of respiratory and diarrhoeal infections based on parents' method were higher than those based on educators' method. CONCLUSIONS: Parents' data lead to larger estimations of incidence rates and are probably more valid than educators' data.

Effectiveness of a training program in reducing infections in toddlers attending day care centers.

The objective of this study was to assess the effectiveness of a hygiene program in reducing the incidence of respiratory and diarrheal diseases in toddlers attending day care centers. A randomized field trial was conducted in 52 day care centers in Quebec, Canada, between September 1, 1996 and November 30, 1997. Absences for any reasons and the daily occurrence of colds and/or diarrhea in toddlers were recorded on calendars by the educators. The number of fecal coliforms on children's hands and on educators' hands was measured during three unannounced visits. Overall, 1,729 children were followed in 47 day care centers for a total of 153,643 child-days. The incidence rate of diarrhea was considerably reduced by the effect of monitoring (IRR = 0.73, 95% CI = 0.54,0.97), and the intervention reduced the incidence rate of upper respiratory tract infections (IRR = 0.80, 95% CI = 0.68,0.93). Monitoring alone also had an important effect in reducing the level of bacterial contamination on children's and educators' hands. The results indicate that both an intervention program and monitoring alone play a role in reducing infections in children attending day care centers.

Estimation of direct and indirect costs because of common infections in toddlers attending day care centers.

OBJECTIVE: To describe both the direct and the indirect costs of illness in a closely followed cohort of toddlers attending day care centers (DCCs) in Québec, Canada. METHODS: Fifty-two DCCs participated in the study. Parents were invited to fill in a calendar on which they would indicate the occurrence of colds, diarrhea, and vomiting, in addition to any actions taken with respect to this occurrence. The participating parents were called biweekly to report the information. The costs reported in this article are based on a period of 6 months of follow-up. The direct costs included medication and visits to a physician whereas indirect costs included alternative care provided by a family member, a babysitter, or an employed parent who missed work. RESULTS: Two hundred seventy-three toddlers were followed from 35 to 182 days during the study period. During a 6-month period, the adjusted average costs per child for medication and consultation were $47.47 (standard deviation [SD] = 52.76) and $49.10 (SD = 51.34), respectively, whereas they amount to $11.51 (SD = 51.19) for care by a babysitter, $35.68 (SD = 94.74) for care by a family member, and $117.12 (SD = 210.29) for a parent missing work (when using opportunity cost). The overall adjusted average total costs per child incurred to the parents and society was $260.70 (SD = 301.25). CONCLUSIONS: The originality of this study was to comprehensively include all costs associated with the care of an ill child attending DCCs. Future research should aim at finding economical ways to decrease illness frequency in toddlers attending day care centers and subsequently the costs they incur.

Parasite contamination of sand and soil from daycare sandboxes and play areas.

OBJECTIVES: To determine if there was parasite contamination in the sand and soil in daycare sandboxes and play areas, with the goal of developing practice guidelines for their management. METHODS: One hundred samples of sand and soil from 10 daycare centres in different regions of the province of Quebec, collected between April 22 and May 6, 1991, were examined. RESULTS: Toxocara eggs were found in both surface and subsurface sand from two Montreal centres and co-occurred with Ascaris species (surface sand) in one centre and with hookworm (surface soil) in the second. Hookworm eggs were also recovered from one centre in the Quebec City region. CONCLUSIONS: These results document the presence of potentially pathogenic helminth parasites in the daycare environment. Evidence from the literature regarding the health risk to children is insufficient and highlights the need for further research into the assessment of the risk of human infection and morbidity, the viability of these parasites under different environmental conditions and practical issues related to the management of sand and soil.

Determinants of AIDS preventive behaviour among dental professionals.

This study was conducted to assess concerns regarding AIDS and to identify determinants of poor preventive behaviour among dentists. Questionnaires were distributed to a random sample of 342 professionals. Respondents showed the lowest knowledge scores on topics dealing with symptoms, epidemiology and AIDS control. The predictors of poor AIDS knowledge were: more than ten years of practice and a strong belief to be professionally susceptible to HIV infection. Sterilization of high speed drills was disappointing; only 14.2% of dentists reported using heat sterilization. Predictors of poor preventive behaviour were: poor ability in clinical AIDS identification, more than ten years of practice and poor knowledge of AIDS prevention and control. Dental burs were the major cause of occupational injury. Professionals who recap needles are three times more likely to sustain needlesticks than those who do not. Our results suggest the need to increase AIDS knowledge and to improve compliance to infection control measures among dentists.

Measurement of 5-hydroxytryptamine turnover rate in rat cerebral arteries.

Two methods for assessing 5-hydroxytryptamine (5-HT) turnover rate have been tested in the cerebral vessels of the rat. The pretreatment of the animals with benserazide 45 min before death brought about an increase in the levels of 5-hydroxytryptophan (5-HTP). When the MAO inhibitor pargyline was injected and the animals killed at different times, there was an exponential decrease in the concentration of 5-hydroxyindole acetic acid (5-HIAA) with time, whereas the increase in 5-hydroxytryptamine was linear only during the first 30 min, thereafter reaching a plateau. This pattern was similar to that obtained in the caudate nucleus after MAO blockade. In the hippocampus, pargyline induced a lineal accumulation of 5-HT throughout the experiment as well as an exponential decay of the 5-HIAA concentration. These results indicate that the turnover rate of 5-HT can be appraised in the rat cerebral arteries either after the rate of disappearance of 5-HIAA or from the accumulation rate of 5-HTP.

Diagnosis of acute acquired toxoplasmosis with the enzyme-labelled antigen reversed immunoassay for immunoglobulin M antibodies.

The reversed enzyme-labelled antigen immunoassay (R-EIA), based on the capture of serum immunoglobulin M antibodies (IgM) and subsequent addition of Toxoplasma gondii soluble antigen tagged with peroxidase and substrate, was evaluated comparatively with the IgM-indirect immunofluorescence test (IgM-IIF) for the detection of anti-toxoplasma IgM antibodies in sera from individuals with diagnosed acute acquired toxoplasmosis. Additional serum groups from normal healthy individuals and sera presenting possible nonspecific reactivities were also evaluated. Complete specificity of R-EIA was shown. There was no correlation between the magnitude of R-EIA results and IgM-IIF titers, but a positive (although not linear) correlation was found between R-EIA and the IgM-IIF titers obtained after adsorption of sera with Staphylococcus aureus protein A. Direct labelling of the antigen by a simple coupling technique facilitated the assay standardization and improved its signal-to-noise ratio.