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Biomedical subjects

G A Ayliffe

Publications and source records attributed to G A Ayliffe.

At least 19 recordsLinked to original sources
PubMed1997

The progressive intercontinental spread of methicillin-resistant Staphylococcus aureus.

Methicillin-resistant Staphylococcus aureus was initially detected in Europe in the 1960s, soon after the introduction of methicillin. Naturally-resistant strains were isolated in some countries before the use of methicillin or related agents. These strains probably spread initially from one or more ancestral genetic clones in natural populations of S. aureus by horizontal transfer and recombination. These original strains, possibly emerging in many countries, then increased in numbers and diversity in hospitals as a result of selection by exposure to antibiotics and by cross-infection. After a decline in the 1970s, new epidemic strains that differed from the original MRSAs emerged in Australia, the United States, and the Irish Republic and have now reached global proportions. Most strains are highly resistant to antibiotics and some are only sensitive to vancomycin or teicoplanin. Intercountry and intercontinental spread has also occurred by transfer of infected or colonized patients or staff. However, the main mode of spread is person-to-person within a unit or hospital and subsequently to other hospitals in the same country. New epidemic strains have continued to emerge and decline for unknown reasons. On the basis of evidence from countries where MRSA is not a problem, it has been suggested that early detection, effective infection control measures, and rational antibiotic use will limit the transmission of these organisms; however, spread is still increasing in many countries.

Global Health↗
PubMed1995

Risk of airborne transmission in an operating theatre containing four ultraclean air units.

This study shows that a single, large, operating theatre (barn) containing four ultraclean operating units (cabins), was highly effective in reducing the number of airborne bacteria in the operating fields providing all occupied ultraclean cabins were functioning correctly. The air flows and bacterial counts during operations within the cabins met the current standard for ultraclean systems (HTM 2025 1994) and there was no evidence of mixing of air between cabins. It is, however, recommended that air flows are regularly checked for compliance with the standard. If failure occurs in any single ultraclean unit, surgery in that cabin should cease as contaminated air may enter from the barn and surrounding cabins. Routine microbiological sampling should not be necessary providing there is no evidence of filter leakage. An operating theatre with several ultraclean operating tables in a single room would appear to be a viable proposition for the future. Considerable savings are likely in revenue costs as much of the air is reused and support services are shared.

Air Microbiology↗
PubMed1995

Evaluation of the Steris System 1 Peracetic Acid Endoscope Processor.

An automated endoscope sterilizing machine, the Steris System 1 Processor, was tested for bactericidal and sporicidal efficacy. The disinfectant, peracetic acid, was diluted to 0.2% within an enclosed system. The exposure time to the disinfectant was 12 min and the overall cycle time ranged from 25-38 min, mean 29 min. Preliminary suspension tests, with and without yeast or serum, showed a log10 reduction of > 5 with Pseudomonas aeruginosa, Staphylococcus aureus and Bacillus subtilis in 5 min with 0.2% peracetic acid. After a routine cycle in the machine, endoscopes contaminated with the same organisms showed no growth. Two of 24 spore strips, containing 10(6) B. subtilis showed a small number of survivors (less than 10 per strip). No significant damage to the endoscope was observed although the number of cycles tested was small (i.e. 31). The advantage of the system is that staff are not directly exposed to the agent, but the costs per cycle are higher than glutaraldehyde, since peracetic acid is not renewed. Unlike other automated processors the Steris machine has no cleaning cycle.

Bacillus subtilis↗
PubMed1993

A test for the assessment of 'hygienic' hand disinfection using rotavirus.

A standardized test procedure is described in which finger tips are inoculated with bovine rotavirus. The level of virus recovered after disinfection of artificially contaminated hands with various disinfectant detergents, alcoholic solutions and alcoholic formulations was determined. The method was found to be easy to perform and reproducible. The most efficient method for removal of virus from fingertips was found to be treatment with alcoholic solutions or products. Soap and water and disinfectant detergents were found to be a much less effective method of removing virus from contaminated hands.

Alcohols↗
PubMed1993

Preliminary study of test methods to assess the virucidal activity of skin disinfectants using poliovirus and bacteriophages.

Two tests for assessing the virucidal activity of antiseptics are proposed. These involve applying either poliovirus (vaccine strain Sabin 1 an) or Escherichia coli bacteriophage (MS2 or K1-5) to the fingertips. Both test viruses are considered safe although poliovirus may be unacceptably tolerant to antiseptics. The use of bacteriophages as test organisms precludes the need for sophisticated recovery systems and can be undertaken readily by any bacteriology laboratory. The virucidal activity of 70%, 80% and 90% ethanol, 7.5% povidone-iodine, and soap and water was assessed using these tests. Thorough cleansing, followed by disinfection with 90% ethanol, was the most effective treatment. Removal of viruses from the gloved hand was also assessed and this was found to be more easily achieved than cleaning and disinfecting the ungloved hand. Wearing gloves protects the hands from viral contamination but changing them after each patient or contact is expensive.

Administration, Topical↗
PubMed1993

Aldehyde disinfectants and health in endoscopy units. British Society of Gastroenterology Endoscopy Committee.

Summary of main recommendations(1) Glutaraldehyde, used in most endoscopy units in the United Kingdom for the disinfection of flexible gastrointestinal endoscopes, is a toxic substance being an irritant and a sensitiser; symptoms associated with glutaraldehyde exposure are common among staff working in endoscopy units.(2) The Control of Substances Hazardous to Health Regulations 1988 (COSHH) obliges the employer to make a systematic assessment of risk to staff of exposure to glutaraldehyde and institute measures to deal effectively with exposure.(3) At present glutaraldehyde remains the first line agent for the disinfection of flexible gastrointestinal endoscopes. Other agents are being developed; a standard means of assessment for flexible endoscope disinfectants should be devised.(4) Equipment and accessories that are heat stable should be sterilised by autoclaving; disposable accessories should be used wherever possible.(5) Flexible gastrointestinal endoscopes should be disinfected within automated washer/disinfectors; trays, bowls or buckets for this purpose are unacceptable.(6) Local exhaust ventilation must be used to control glutaraldehyde vapour. Extracted air may be discharged direct to the atmosphere or passed over special absorbent filters and recirculated. Such control measures must be regularly tested and records retained.(7) Endoscope cleaning and disinfection should be carried out in a room dedicated to the purpose, equipped with control measures to maintain the concentration of glutaraldehyde vapour at a level certainly below the current occupational exposure standard of 0.2 ppm and preferably below the commonly used working limit of 0.1 ppm. Sites other than the endoscopy unit where endoscopy is regularly performed, such as the radiology department, should have their own fully equipped cleaning and disinfection room.(8) COSHH limits the use of personal protective equipment to those situations where other measures cannot adequately control exposure. Such equipment includes nitrile rubber gloves, apron, chemical grade eye protection, and respiratory protective equipment for organic vapours.(9) Monitoring of atmospheric levels of glutaraldehyde should be performed by a competent person such as an occupational hygienist; the currently preferred method of sampling uses a filtration technique, the commercially available meters being less reliable.(10) Health surveillance of staff is mandatory; occupational health records must be retained for 30 years.(11) Endoscopy staff must be informed of the risks of exposure to glutaraldehyde and trained in safe methods of its control. Only staff who have completed such an education and training programme should be allowed to disinfect endoscopes.(12) The unsafe use of glutaraldehyde has significant health and legal consequences; the safe use of glutaraldehyde may have revenue consequences that contribute significantly to the cost of gastrointestinal endoscopy.

Aldehydes↗
PubMed1991

Masks in surgery?

Explore the source record for details and available documents.

Clinical Trials as Topic↗
PubMed1991

A test procedure for evaluating surgical hand disinfection.

A technique for assessing the immediate and prolonged efficacy of surgical scrubs and alcoholic hand rubs is described. A mean baseline count is obtained from all volunteers and logarithmic reductions in resident skin flora immediately after one or more applications, and after wearing gloves for 3 h, are measured. Loose-fitting surgical gloves are used for sampling resident flora. Preparations were applied using a standard technique for 2 min, apart from one test with 70% isopropanol (IPA) in which the application time was 30 s. Two studies are described, one of which compared four chlorhexidine scrubs, and the second 70% IPA, 7.5% povidone-iodine scrub, 2% triclosan cleanser and unmedicated bar soap. In spite of their constituent similarity, the four chlorhexidine scrubs varied considerably in efficacy and user acceptability. A 2 min application of 70% IPA was the most effective treatment, and gave log10 reductions of 1.65 for immediate and 1.58 for prolonged effect. This was marginally more effective than a 30 s application, but the difference was not significant. 'Hibiscrub' was the most effective aqueous formulation and gave reductions of 1.01 for immediate effect and 1.16 for prolonged effect. The test described could be used by reference centres and manufacturers to assess the efficacy of new and existing surgical hand disinfection formulations.

Adolescent↗
PubMed1990

Acquired immune deficiency syndrome: recommendations of a Working Party of the Hospital Infection Society.

Unified procedures to control those infections that are transmitted by inoculation of blood are recommended. These should be applied to patients with acquired immune-deficiency syndrome (AIDS), AIDS-related complex, persistent generalized lymphadenopathy or hepatitis B, those with serological evidence of infection by human immunodeficiency virus or hepatitis B virus, and those in medical and social categories with a higher than average prevalence of such infections. When the identification of these categories of patient would be particularly difficult, the precautions should be applied to all patients, in situations of high risk for inoculation incidents. Rational infection-control measures, based on the known mode of spread, permit efficient management of infected patients, with satisfactory protection of staff and other patients.

Acquired Immunodeficiency Syndrome↗