A membrane filter technique for testing disinfectants.

A membrane filter was used for assessing the surface disinfecting activity of phenolic disinfectants and a chloroxylenol disinfectant. The influence of the type of organism, inoculum size, and hardness of water was investigated. Pseudomonas aeruginosa was chosen for the standardized test. Disinfectant solutions were prepared in water of 300 ppm hardness and applied for two and a half minutes and eight minutes to the bacteria deposited from filtration of 1 ml of a suspension containing 10-6 bacteria. The membrane filter test has certain advantages over many tests, eg, all organisms surviving after treatment can be counted and residual disinfectant is easily removed.

Tests of disinfection by heat in a bedpan washing machine.

Tests of effectiveness of disinfection of metal and polypropylene bedpans were made in a washer fitted with a steam generator. Broth cultures of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, or Streptococcus faecalis (approximately 4 x 10(8) organisms) were sealed in lengths of capillary tubing and attached to the surface of the pans. In other tests, pans were contaminated with an artificial soil containing Str. faecalis (10(8) organisms/ml). In both series of tests, counts of surviving organisms were made at the end of the washing and disinfection cycle. The tests using capillary tubes showed that the Gram-negative bacilli were effectively killed, but not necessarily Gram-positive cocci. However, when incorporated in standard soil, Str. faecalis was killed or removed during the cycle. The results indicate that the disinfection process was effective for metal bedpans, but less so for polypropylene. Possible disadvantages and modification of the machine are suggested.

Biomarkers of diabetes risk in the National Diet and Nutrition Survey rolling programme (2008-2011).

This study describes the distribution of glycosylated haemoglobin (Hb(A1c)) and glucose concentrations in the combined year 1 (2008-2009), year 2 (2009-2010) and year 3 (2010-2011) of the National Diet and Nutrition Survey (NDNS) rolling programme. The NDNS rolling programme is a nationally representative survey of food consumption, nutrient intakes and nutritional status of people aged 1.5 years and over living in England, Wales, Scotland and Northern Ireland. The study population comprised survey members who completed three or four days of dietary recording and who provided a blood sample. After excluding survey members with self-reported diabetes (n=25), there were 1016 results for HbA1c and 942 for glucose (not the same individuals in each case). Around 5.4% of men and 1.7% of women aged 19-64 years, and 5.1% of men and 5.9% of women aged ≥65 years had impaired fasting glucose (glucose concentrations 6.1-6.9 mmol/L). Over 20% of men aged ≥65 years had fasting glucose concentrations above the clinical cut-off for diabetes (≥7 mmol/L) compared to 2.1% of women of similar age (p=0.007). Similarly, 16.4% of men had Hb(A1c) concentrations ≥6.5%, compared to 1.5% of women (p=0.003). Children and teenagers had fasting glucose and Hb(A1c) values largely within the normal range. To conclude, this is the first study to provide data on the distribution of HbA1c and glucose concentrations in a nationally representative sample of the British population. The high prevalence of men aged ≥65 years with Hb(A1c) and glucose concentrations above the clinical cut-off of diabetes warrants further attention.

Past, present and future use of low temperature steam/formaldehyde and ethylene oxide sterilisation systems.

The development of medical equipment that cannot adequately be sterilised or disinfected has caused growing concern in recent years. Areas of concern are equipment that is likely to be damaged by normal autoclaving temperatures, and is therefore heat labile, or is so complicated in structure that adequate penetration of chemical disinfectants is unlikely. The need has led to the search for a method that would give adequate penetration of a bacteriocide without the use of excessive temperatures. The penetrative power of gaseous sterilant/disinfectants appears to be the area most likely to fulfill these considerations. Ethylene oxide (Phillips 1949) and Low Temperature Steam, with or without Formaldehyde, have been investigated by various workers.

Methods of decontamination of anaesthetic equipment: daily sessional exchange of circuits.

Sampling of untreated anaesthetic circuits showed heavy bacterial contamination. Daily or twice daily sessional exchange of circuits (i.e. use of one circuit for up to nine patients) considerably reduced the extent of contamination. Equipment was effectively treated by steam at high or low temperature or by immersion in glutaraldehyde. Steam at high temperature (134 degrees C) damaged reservoir bags on repeated treatment, whereas low temperature steam (68 degrees C) was satisfactory. Treatment with glutaraldehyde was also satisfactory, but slightly less reliable and its smell was difficult to remove from the equipment after repeated immersion.

Coated bedpans: their cleaning and disinfection.

This paper reports on tests of cleaning and disinfection of stainless steel bedpans which have been coated with either a silicone grease or polytetrafluoroethylene (PTFE). The coatings were applied manually using an aerosol spray (silicone grease and PTFE), and by an industrial process (PTFE). Soils used comprised (i) British Standard Soil (B.S., 1966), (ii) human serum albumin labelled with technetium-99m (HSA-Tc), and (iii) a suspension of Streptococcus faecalis in broth. Tests of cleaning and disinfection were carried out in automatic washing and steam disinfector machines. Results show that aerosol spraying impairs the cleaning process but that bedpans coated by the industrial process with PTFE are superior to uncoated bedpans.

The Bowie/Dick test: an alternative way.

Since notification from the DHSS that the Lantor Cube (DHSS 1986) has been accepted, and approved as equivalent to the towel pack for the daily Bowie and Dick testing of porous load autoclaves, considerable interest has been shown in cost comparison between the Lantor cube and the towel pack.

Disinfection in upper-digestive-tract endoscopy in Britain.

A contaminated endoscope may infect patients at upper-gastrointestinal-tract endoscopy (oesophago-gastro-duodenoscopy and endoscopic cholangio-pancreatography) either by the transmission of infection from one patient to another or by inoculation of potentially pathogenic bacteria which have multiplied in the instrument and ancillary equipment during storage. These dangers can be eliminated by careful disinfection with glutaraldehyde, other aldehyde disinfectants, or povidone-iodine. Few centres in Britain are using an effective disinfection procedure and of those who have used glutaraldehyde (the most widely employed) 37% have had serious problems with staff sensitivity. A quick, effective, and safe method for the disinfection of fibreoptic instruments is urgently needed.