Decontamination of minimally invasive surgical endoscopes and accessories.

(1) Infections following invasive endoscopy are rare and are usually of endogenous origin. Nevertheless, infections do occur due to inadequate cleaning and disinfection and the use of contaminated rinse water and processing equipment. (2) Rigid and flexible operative endoscopes and accessories should be thoroughly cleaned and preferably sterilized using properly validated processes. (3) Heat tolerant operative endoscopes and accessories should be sterilized using a vacuum assisted steam sterilizer. Use autoclavable instrument trays or containers to protect equipment during transit and processing. Small bench top sterilizers without vacuum assisted air removal are unsuitable for packaged and lumened devices. (4) Heat sensitive rigid and flexible endoscopes and accessories should preferably be sterilized using ethylene oxide, low temperature steam and formaldehyde (rigid only) or gas plasma (if appropriate). (5) If there are insufficient instruments or time to sterilize invasive endoscopes, or if no suitable method is available locally, they may be disinfected by immersion in 2% glutaraldehyde or a suitable alternative. An immersion time of at least 10 min should be adopted for glutaraldehyde. This is sufficient to inactivate most vegetative bacteria and viruses including HIV and hepatitis B virus (HBV). Longer contact times of 20 min or more may be necessary if a mycobacterial infection is known or suspected. At least 3 h immersion in glutaraldehyde is required to kill spores. (6) Glutaraldehyde is irritant and sensitizing to the skin, eyes and respiratory tract. Measures must be taken to ensure glutaraldehyde is used in a safe manner, i.e., total containment and/or extraction of harmful vapour and the provision of suitable personal protective equipment, i.e., gloves, apron and eye protection if splashing could occur. Health surveillance of staff is recommended and should include a pre-employment enquiry regarding asthma, skin and mucosal sensitivity problems and lung function testing by spirometry. (7) Possible alternative disinfectants to glutaraldehyde include peracetic acid (0.2-0.35%), chlorine dioxide (700-1100 ppm) and superoxidized water. These are very effective, killing vegetative bacteria, including mycobacteria, and viruses in 5 min and bacterial spores in 10 min. An endorsement of compatibility with endoscopes, accessories and processing equipment is required from both the solution/device manufacturer and the endoscope manufacturer. Other important considerations are stability, cost and safety from the user and environmental standpoints. (8) Cleaning and disinfection or sterilization should be undertaken by trained staff in a dedicated area, e.g., SSD or TSSU. A suitable training programme is described. (9) If endoscopes are processed by immersion in disinfectants, harmful residues must be removed by thorough rinsing. Sterile or bacteria free water is essential for rinsing all invasive endoscopes and accessories to prevent recontamination. (10) If an automated washer disinfector is used it must be effective, non-damaging, reliable, easy to use and its performance regularly monitored. (11) If used, washer disinfectors and other processing equipment should be disinfected on a regular basis, i.e., between patients or at the start of each session. This will prevent biofilm formation and recontamination of instruments during rinsing. Disinfection should include the water treatment system, if present. (12) To comply with the Medical Devices Directive, manufacturers are obliged to provide full details on how to decontaminate the reusable devices they supply. This should include details of compatibility with heat, pressure, moisture, processing chemicals and ultrasonics. (13) The Infection Control Team should always be involved in the formulation and implementation of decontamination policies. Wherever possible, the national good practice guidelines produced by the Medical Devices Agency and/or professional societies shoul

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.

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.

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.

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.

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.

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.

Locus of control of behaviour: is high externality associated with substance misuse?

Personal control and responsibility are key themes in the therapeutic use of 'motivational interviewing'. This popular method of counselling has suggested that clients need to believe they have a significant degree of control over their behaviour if they are to make progress. Using a well validated psychological test on locus of control of behaviour, our research sought to establish whether active misusers really believed they had less personal control than non-misusers. To establish this a sample of misusers was tested and compared with three diverse, comparable groups. Possible confounding factors such as age, sex and class were controlled for. T tests established a significant difference between the active misusers and the other sampled groups. Further, a regression analysis of variance, calculated to explain the differing external scores offered no reasonable explanation as far as age, sex and class were concerned. Alternatively, self diagnosed substance misuse accounted for 23% of the variation in scores. We concluded, therefore, that high externality scores are a good indicator of active misusing behaviour and that beliefs about personal control are important to address, if one is to increase the chances of a positive client outcome.

Role of the environment of the operating suite in surgical wound infection.

Most surgical wound infections are acquired in the operating room from the patient's own microbial flora. The remainder are acquired mainly from the staff in the operating room during surgery. The inanimate environment (e.g., walls, floors, and surgical instruments) has little relevance to the spread of infection. Because the air is an important route of spread in joint prosthesis operations, the routine use of an ultraclean air system and exhaust-ventilated clothing is frequently recommended. The value of such a system in other types of clean surgery is doubtful, but other measures, such as the following, may provide similar results at less cost: reduction of the number of persons in the operating room; a policy of not opening doors during operations; the use of comfortable, washable, bacteria-impermeable clothing by the operating-room staff; and concentration of the airflow over the operation site rather than over the whole operating room.