Low-temperature decontamination with hydrogen peroxide or chlorine dioxide for space applications.

The currently used microbial decontamination method for spacecraft and components uses dry-heat microbial reduction at temperatures of >110°C for extended periods to prevent the contamination of extraplanetary destinations. This process is effective and reproducible, but it is also long and costly and precludes the use of heat-labile materials. The need for an alternative to dry-heat microbial reduction has been identified by space agencies. Investigations assessing the biological efficacy of two gaseous decontamination technologies, vapor hydrogen peroxide (Steris) and chlorine dioxide (ClorDiSys), were undertaken in a 20-m(3) exposure chamber. Five spore-forming Bacillus spp. were exposed on stainless steel coupons to vaporized hydrogen peroxide and chlorine dioxide gas. Exposure for 20 min to vapor hydrogen peroxide resulted in 6- and 5-log reductions in the recovery of Bacillus atrophaeus and Geobacillus stearothermophilus, respectively. However, in comparison, chlorine dioxide required an exposure period of 60 min to reduce both B. atrophaeus and G. stearothermophilus by 5 logs. Of the three other Bacillus spp. tested, Bacillus thuringiensis proved the most resistant to hydrogen peroxide and chlorine dioxide with D values of 175.4 s and 6.6 h, respectively. Both low-temperature decontamination technologies proved effective at reducing the Bacillus spp. tested within the exposure ranges by over 5 logs, with the exception of B. thuringiensis, which was more resistant to both technologies. These results indicate that a review of the indicator organism choice and loading could provide a more appropriate and realistic challenge for the sterilization procedures used in the space industry.

Meticillin-resistant Staphylococcus aureus is more resistant to vaporized hydrogen peroxide than commercial Geobacillus stearothermophilus biological indicators.

BACKGROUND: Vaporized hydrogen peroxide (VHP) is increasingly used in the decontamination of hospital isolation rooms. Commercially available bioindicators, most frequently Geobacillus stearothermophilus spores, are used to assess the efficacy of the decontamination phase. Staphylococcus aureus, including meticillin-resistant S. aureus (MRSA), produce catalase, which breaks down VHP, therefore potentially making it resistant to the decontamination phase. AIM: This investigation was designed to assess the resistance of meticillin-resistant S. aureus to VHP in comparison with commercially available biological indicators loaded with spores. METHODS: Stainless steel indicators were prepared with the same loading of MRSA (NCTC 13142) as commercially available indicators of G. stearothermophilus (ATCC 7953) (∼3.1×10(6) spores) and both indicators were exposed to a vapour hydrogen peroxide cycle (750 ppm). At set time-points during the exposure period, indicators containing both organisms were removed for processing and enumeration to compare survivability. FINDINGS: During the exposure period the recovery of MRSA from the coupons was between 1.5 and 3.5 log(10) higher than the recovery of G. stearothermophilus spores (P<0.05). This greater resistance may be due to the production of catalase which could break down the hydrogen peroxide, resulting in a reduction of the effectiveness of VHP. CONCLUSION: These findings highlight that the reduction achieved with a commercially available biological indicator cannot always be extrapolated to other micro-organisms. It must be recognized that although gaseous decontamination is the final step of the decontamination process, pre-cleaning of surfaces must be carried out to reduce the microbial loading being exposed.

Evaluation of the sporicidal activity of different chemical disinfectants used in hospitals against Clostridium difficile.

Decontamination of surfaces and medical equipment is integral to the control of Clostridium difficile transmission, and many products claim to inactivate this bacterium effectively. Thirty-two disinfectants were tested against spores of C. difficile in a suspension test based on European Standard BS EN 13704:2002, with contact times of 1 and 60 min in simulations of clean (0.3% albumin) and dirty (3% albumin) conditions. The addition of a 1-min contact time was chosen as a more realistic simulation of probable real-life exposures in the situation being modelled than the 60 min specified by the Standard. The manufacturer's lowest recommended concentrations for use were tested. Sixteen products achieved >10(3) reduction in viability after 60 min (the pass criterion for the Standard) under both clean and dirty conditions. However, only eight products achieved >10(3) reduction in viability within 1 min under dirty conditions. Three products failed to reduce the viability of the C. difficile spores by a factor of 10(3) in any of the test conditions. This study highlights that the application of disinfectants claiming to be sporicidal is not, in itself, a panacea in the environmental control of C. difficile, but that carefully chosen environmental disinfectants could form part of a wider raft of control measures that include a range of selected cleaning strategies.

HDR imaging evaluation of a NT-proBNP test with a mobile phone.

The determination of NT-proBNP levels is key for the monitoring of patients with diagnosed heart failure and it is a routine measurement typically performed at health care centers, which would benefit from decentralized alternatives. Here we investigate the quantitative evaluation of a well-established NT-proBNP test using a standard mobile phone (Nokia 6720) as measuring platform rather than a dedicated instrument. A Java ME software developed for this application controls the illumination and imaging of the proBNP test under defined time intervals, which enables the composition of multi-exposure sets that are processed as high dynamic range (HDR) images for contrast enhancement. The results show that HDR processing significantly increases the sensitivity and resolution of the technique achieving a performance within the diagnostics range. These results demonstrate the feasibility to exploit a ubiquitous device to decentralize the evaluation of a routine test and identify key processing alternatives to bring the performance of such systems within the diagnostics range.

Meeting the health care needs of school-age children with intellectual disability.

Intellectual disability (ID) is common and is known to affect 1-3% of the population. There is a lack of medical epidemiological data in Ireland for this group. Such data is necessary in providing the evidence base to plan for rehabilitation services, provide ongoing health care and consider prevention strategies. We report on the underlying diagnosis and co-morbidities of the school-age children in one Health Service Executive area. There were 97 children. Forty seven (48.5%) of the children have a chromosomal or genetic explanation for their disability, 16 (16.5%) have an environmental cause and 34 (35%) have no identified cause. The children have complex medical needs: 35 (36%) have epilepsy and 34 (35%) have gastro-intestinal problems; 24 (25%) have a respiratory condition and 15 (15%) have congenital heart disease. Thirty one (32%) and 30 (31%) have visual and hearing impairment respectively. Expansion of the National Intellectual Disability Database should be explored to include the medical epidemiological data to inform the future development of services for Intellectually Disabled.

Thyroid dysfunction in Down's syndrome and screening for hypothyroidism in children and adolescents using capillary TSH measurement.

UNLABELLED: Thyroid dysfunction is more common in individuals with Down's syndrome (DS) than in the general population, whose clinical features can mask the presenting signs and symptoms of hypothyroidism. Biochemical screening is necessary; however, venepuncture may be difficult. AIMS: To assess the prevalence of thyroid dysfunction in children and adolescents with DS and the feasibility of screening for hypothyroidism using capillary dried blood spot thyroid stimulating hormone (TSH) from infancy. METHODS: 394 children (217 boys, 177 girls) were clinically assessed for thyroid dysfunction and 305 children (aged 4 months to 18.9 years) were screened for hypothyroidism by capillary whole blood TSH sample. RESULTS: Thyroid dysfunction was detected in 4.6%, with 50% unscreened since neonatal screening. Parents reported minimal distress by fingerprick screening. CONCLUSION: DS is associated with an increased prevalence of thyroid dysfunction, particularly in preschool children. Biochemical screening is essential and capillary whole blood TSH sampling for hypothyroidism is feasible, less invasive and acceptable.

Guidelines for the medical management of Irish children and adolescents with Down syndrome.

Down syndrome (DS) is the most common chromosomal cause of developmental disability in Ireland. Children with DS have a high incidence of associated treatable medical disorders where early intervention carries a better outcome. Currently there are no agreed protocols for the screening and management of children and adults with DS in Ireland. A cross-sectional study of 394 children and adolescents was undertaken in the Eastern Regional Health Authority (ERHA) to assess the medical needs of children and adolescents with DS, in order to develop medical management guidelines. This study provides evidence-based data that children and adolescents with DS have a high incidence of treatable medical disorders, which supports the need for the medical management guidelines presented.

Infantile hypertrophic cardiomyopathy with QT prolongation.

A neonate presented with neonatal myocardial dysfunction and long QT interval with subsequent appearance of hypertrophic cardiomyopathy at one week of age. Maternal glucose metabolism was normal. By 15 months of age the hypertrophy had largely resolved but the long QT persisted. The possible relationship between these conditions is discussed.