Salmonella Typhimurium infections transmitted by chlorine-pretreated clover sprout seeds.
(65/846)
Raw seed sprouts have caused numerous outbreaks of enteric infections. Presoaking seeds in a 20,000 mg/liter (ppm) calcium hypochlorite solution before sprouting is recommended to reduce bacterial contamination and infection risk. In 1999, the authors investigated an outbreak of Salmonella serotype Typhimurium infections in Colorado. In a case-control study, they matched 20 cases with 58 controls by age, sex, and telephone prefix; 10 (52%) of 19 cases and no controls recalled eating raw alfalfa-style sprouts in the 5 days before the patient's illness (p < 0.00001). Traceback implicated clover sprouts grown from seeds shared by two sprouters. The time period and region over which these sprouts were sold matched the occurrences of 112 culture-confirmed illnesses. Only one of the sprouters presoaked seeds as recommended, and fewer infections were attributable to this sprouter (0.29 vs. 1.13 culture-confirmed infections/50-pound (110.1-kg) bag of seed). After recall of the implicated sprouts and seed, S. Typhimurium illnesses declined. Contaminated raw clover sprouts can cause outbreaks of enteric illness. Presoaking contaminated seeds in a 20,000 mg/liter calcium hypochlorite solution reduces, but does not eliminate, the risk of infection. Until safer production methods are developed, persons eating raw sprouts continue to risk developing potentially serious gastrointestinal illness. (+info)
Initial fast reaction of bromine on reovirus in turbulent flowing water.
(66/846)
An apparatus is described for precise observation of the kinetics of the initial fast reaction of bromine with reovirus in turbulent flowing water. When quantitative electron microscopy shows that virus suspensions are essentially all single particles, the loss of infectivity follows first-order kinetics, the plaque titer falling at the rate of 3 log10 units/s at pH 7, 2 C, and at a 3-muM bromine concentration. Virus suspensions containing small aggregates (2 to 10/clump) exhibit a constantly decreasing disinfection rate with bromine. At a survival level of 10(-3) for single virions, the aggregated preparations have lost only 99% of their plaque titer and 10(-4) is reached only after 4 s of exposure. The disinfection rate does not appear to be a simple function of the size and frequency of aggregates in the virus suspension even when the aggregates contain no foreign material. Unpurified virus preparations (crude freeze-thaw lysates of infected cells) are shown, by zonal centrifugation, to contain 50% to over 90% of the infectivity in large, fast sedimenting aggregates. Such aggregates would strongly influence the bromine resistance of virus in polluted water. (+info)
GENebu Project: home nebulizer use and maintenance in Italy.
(67/846)
Due to the lack of information on this topic, the Educational Group of the Italian Association of Hospital Pneumologists performed an open, multicentre, observational survey to evaluate home nebulizer practices in Italy. From May-December 1999, all patients attending one of the 27 participating chest clinics throughout Italy and who were or had been using a home nebulizer in the previous 6 months were consecutively enrolled. All patients completed a self-administered questionnaire on their current practices of home nebulization. Of the 1,721 questionnaires delivered, 1,257 were returned with an overall response rate of 73%. Most patients (82.8%) reported using their nebulizer for bronchopulmonary symptoms and the remaining patients only used theirs for upper respiratory tract diseases. Subjects using their nebulizer for lower respiratory symptoms were older (p<0.001), predominantly female (p<0.001) and used their nebulizer more frequently (p<0.001). Forty per cent of patients >60 yrs old used their nebulizer regularly, at least once a day. More than 60% of respondents never received any information from healthcare workers on the correct usage of their nebulizer, and >75% received no information on nebulizer hygiene and care. Patients who received information on the use and maintenance of their nebulizer from caregivers more commonly attended to these practices (p<0.01). The present survey suggests that home nebulizer use and maintenance in Italy are heterogeneous, and there is the need to implement better nebulizer practice. (+info)
Viability of Acanthamoeba after exposure to a multipurpose disinfecting contact lens solution and two hydrogen peroxide systems.
(68/846)
BACKGROUND/AIM: Contact lens cases contaminated with Acanthamoeba are a major risk factor for an infection of the eye. In this study the anti-Acanthamoeba activity of three different contact lens storage solutions was tested. METHODS: A new multipurpose contact lens storage solution (Meni Care Plus) and a two step (Titmus H(2)O(2)) and one step (Oxysept Comfort) hydrogen peroxide system were tested for their effects on trophozoites and cysts of three different Acanthamoeba species: A castellanii, A hatchetti, and A lenticulata. RESULTS: After a soaking time of 8 hours (overnight soaking of contact lenses) the Titmus H(2)O(2) 0.6% solution showed very good amoebicidal effects, while Oxysept Comfort 3% H(2)O(2) could not effectively destroy the cysts of any of the three tested species. Viable cysts of the species A lenticulata and A hatchetti were still present after exposure to Meni Care Plus (0.0005% PHMB) for 8 hours. CONCLUSION: Not all of the three tested contact lens storage solutions have sufficient amoebicidal effects. The two step peroxide system Titmus H(2)O(2) is a very effective disinfectant contact lens solution in order to avoid a possible Acanthamoeba infection of the eye. (+info)
Effect of commercial-scale high-temperature, short-time pasteurization on the viability of Mycobacterium paratuberculosis in naturally infected cows' milk.
(69/846)
Raw cows' milk naturally infected with Mycobacterium paratuberculosis was pasteurized with an APV HXP commercial-scale pasteurizer (capacity 2,000 liters/h) on 12 separate occasions. On each processing occasion, milk was subjected to four different pasteurization treatments, viz., 73 degrees C for 15 s or 25 s with and without prior homogenization (2,500 lb/in(2) in two stages), in an APV Manton Gaulin KF6 homogenizer. Raw and pasteurized milk samples were tested for M. paratuberculosis by immunomagnetic separation (IMS)-PCR (to detect the presence of bacteria) and culture after decontamination with 0.75% (wt/vol) cetylpyridinium chloride for 5 h (to confirm bacterial viability). On 10 of the 12 processing occasions, M. paratuberculosis was detectable by IMS-PCR, culture, or both in either raw or pasteurized milk. Overall, viable M. paratuberculosis was cultured from 4 (6.7%) of 60 raw and 10 (6.9%) of 144 pasteurized milk samples. On one processing day, in particular, M. paratuberculosis appeared to have been present in greater abundance in the source raw milk (evidenced by more culture positives and stronger PCR signals), and on this occasion, surviving M. paratuberculosis bacteria were isolated from milk processed by all four heat treatments, i.e., 73 degrees C for 15 and 25 s with and without prior homogenization. On one other occasion, surviving M. paratuberculosis bacteria were isolated from an unhomogenized milk sample that had been heat treated at 73 degrees C for 25 s. Results suggested that homogenization increases the lethality of subsequent heat treatment to some extent with respect to M. paratuberculosis, but the extended 25-s holding time at 73 degrees C was found to be no more effective at killing M. paratuberculosis than the standard 15-s holding time. This study provides clear evidence that M. paratuberculosis bacteria in naturally infected milk are capable of surviving commercial high-temperature, short-time pasteurization if they are present in raw milk in sufficient numbers. (+info)
Effect of oxidizing disinfectants (chlorine, monochloramine, and ozone) on Helicobacter pylori.
(70/846)
The susceptibility of Helicobacter pylori to disinfectants was compared to that of Escherichia coli. H. pylori is more resistant than E. coli to chlorine and ozone but not monochloramine. H. pylori may be able to tolerate disinfectants in distribution systems and, therefore, may be transmitted by a waterborne route. (+info)
Skin disinfection and acupuncture.
(71/846)
The need for skin disinfection before insertion of an acupuncture needle is controversial and there is no specific research on this topic. However research and observations on the effect of, and the need for, skin disinfection before injections forms a good analogy of acupuncture. Whilst micro-organisms present on the surface of the skin are accessible to disinfection, those located under the surface in ducts, glands and follicles are out of reach and can be inoculated into the sterile tissues below by needle insertion. Fortunately, the bacteria resident on the skin have a low potential to cause infection if host immunity is not severely impaired or compromised by the long-term presence of foreign material, such as a surgical stitch. Disinfection of clean skin before injection is not generally considered necessary and observations of lack of infection following injections without prior skin disinfection support this; however, contamination by micro-organisms not normally resident on skin can pose a higher risk of infection. If skin is visibly soiled, it should be washed and if needle insertion is near an infected or contaminated site, it should be disinfected with alcohol. Practitioner hand hygiene between patients is important, even if gloves are worn. Hands should be washed with soap or detergent and water, or an alcohol handrub can be used if hands are physically clean. (+info)
Chlorine disinfection of atypical mycobacteria isolated from a water distribution system.
(72/846)
We studied the resistance of various mycobacteria isolated from a water distribution system to chlorine. Chlorine disinfection efficiency is expressed as the coefficient of lethality (liters per minute per milligram) as follows: Mycobacterium fortuitum (0.02) > M. chelonae (0.03) > M. gordonae (0.09) > M. aurum (0.19). For a C.t value (product of the disinfectant concentration and contact time) of 60 mg.min.liter(-1), frequently used in water treatment lines, chlorine disinfection inactivates over 4 log units of M. gordonae and 1.5 log units of M. fortuitum or M. chelonae. C.t values determined under similar conditions show that even the most susceptible species, M. aurum and M. gordonae, are 100 and 330 times more resistant to chlorine than Escherichia coli. We also investigated the effects of different parameters (medium, pH, and temperature) on chlorine disinfection in a chlorine-resistant M. gordonae model. Our experimental results follow the Arrhenius equation, allowing the inactivation rate to be predicted at different temperatures. Our results show that M. gordonae is more resistant to chlorine in low-nutrient media, such as those encountered in water, and that an increase in temperature (from 4 degrees C to 25 degrees C) and a decrease in pH result in better inactivation. (+info)