Sporicidal activity of disinfectants as one possible cause for bacteria in patient-ready endoscopes.

Four endoscopes were cleaned by an experienced endoscopy technician using an enzyme detergent solution with brushing, rinsing with tap water, and then high-level disinfection in an automatic endoscope reprocessing machine using CIDEX orthophthalaldehyde solution (CIDEX OPA). After disinfection, the channels of these patient-ready endoscopes were flushed with sterile neutralizing medium, brushed with a sterile brush, and then flushed again with sterile medium. The effluent from each flush was collected in sterile bottles, immediately returned on ice to a laboratory, and tested for the presence of bacteria. An average of about 200 colony-forming units of bacteria were recovered from each endoscope. Upon staining and microscopic examination, 3 of these colonies were spore-forming bacteria, and 7 colonies were nonspore-forming bacteria. These results suggest that the endoscopes might have been contaminated with a biofilm. Bacterial biofilms have been speculated to commonly occur in endoscopes as a result of the many possible inadequacies of cleaning, disinfecting, rinsing, drying, storage, and other functions associated with the difficulties of reprocessing endoscopes. As one possible cause for a biofilm, three high-level disinfectants (CIDEX activated dialdehyde solution, CIDEX OPA, and Aldahol high-level disinfectant) were tested for their sporicidal activity against high-protein or low-protein cultures of spore-forming bacteria in suspension. The potential importance of killing spore-forming bacteria within a practical exposure time in order to prevent the formation of biofilms is discussed.

Evaluation of the effectiveness of an enzymatic cleaner and glutaraldehyde-based disinfectant for chemothermal processing of flexible endoscopes in washer-disinfectors in accordance with prEN ISO 15 883.

BACKGROUND AND STUDY AIMS: This study evaluated the effectiveness of the cleaning process, the disinfection process, and a combination of the two in accordance with the new international standard, prEN ISO 15 883. MATERIALS AND METHODS: The cleaning process consisted of a 1-min prerinse at 20 degrees C, followed by a 5-min cleaning step at 45 degrees C (with an enzymatic cleaner, 0.5 %), followed by a 1-min interim rinse from 45 degrees C to 55 degrees C. The disinfection process consisted of a 1-min prerinse at 20 degrees C, followed by a 5-min disinfection step at 55 degrees C (with a glutaraldehyde-based disinfectant, 1 %), followed by two final rinses of 1 min each at 55 degrees C. Transparent test pieces were contaminated with a mixture of blood and ENTEROCOCCUS FAECIUM, and were assessed for visible cleanliness and microbial load. RESULTS: Cleaning alone, disinfection alone, and the combination of the two always led to visible cleanliness of all test pieces. The cleaning process revealed a mean reduction factor of > or = 4.6 (n = 6); the disinfection process revealed a mean reduction factor of > or = 9.0 (n = 6), and the combination of the two was found to reduce the test organism in the WD440 by 9.0 +/- 0.2 log (10) steps (n = 12) and in the AdaptaScope by 9.3 +/- 0.4 log (10) steps (n = 5). CONCLUSIONS: Overall, the entire process was found to be very effective and compatible for reprocessing flexible endoscopes in washer-disinfectors. No visible residual blood was found, despite the use of glutaraldehyde in the disinfection phase. These findings once again emphasize the importance of effective cleaning for the overall results when reprocessing flexible endoscopes.

[Occupational exposure to glutaraldehyde during its use in chemical disinfection of endoscopes]. / Esposizione occupazionale a glutaraldeide nel corso della disinfezione chimica di endoscopi.

BACKGROUND: To evaluate the air pollution experimentally produced by different solutions of glutaraldehyde due to the activity of chemical disinfection in a flexible endoscopy unit. METHODS: The glutaraldehyde environment concentrations due to the use of 3 solutions (2% solution and its 1:5 and 1:20 dilutions) were measured by liquid chromatography after sampling on specific cartridges and by fotoacoustic method. RESULTS: Only after the use of the most concentrated solution it was possible to detect glutaraldehyde in the environment air, with values between 0.2 and 0.3 mg/m3 and during specific activities such as after shaking the disinfecting solutions. CONCLUSIONS: When the usual preventive recommendations are respected, the use of 1:5 and 1:20 solution of 2% glutaraldehyde products does not produce air concentrations of the aldehyde exceeding the current, even restrictive, limits proposed by industrial hygienists.

Comparative sensitivity of 13 species of pathogenic bacteria to seven chemical germicides.

BACKGROUND: The relative resistance of diverse human bacterial pathogens to commonly used germicidal agents has not been established. METHODS: We measured by titration the survival of thirteen different bacteria after exposure to glutaraldehyde, formaldehyde, hydrogen peroxide, peracetic acid, cupric ascorbate, sodium hypochlorite, or phenol. RESULTS: Our comparative experiments allowed classification of the organisms' survival into four groups: (a) Pseudomonas aeruginosa and Staphylococcus aureus showed the most resistance, (b) Clostridium perfringens, Salmonella typhimurium, Staphylococcus epidermidis, and Escherichia coli O157:H7 showed intermediate resistance, (c) Listeria monocytogenes, Shigella sonnei, and Vibrio parahaemolyticus survived some treatments with chemical agents only in the presence of protecting protein (serum albumin), and (d) Vibrio cholerae, Vibrio vulnificus, Bacillus cereus, and Yersinia enterocolitica did not survive any of the treatments applied. CONCLUSION: We found species that more frequently survived exposure to germicidal agents were also those most commonly reported in association with hospital infections. Our findings suggest that resistance to disinfectants may be more important than pathogenicity in determining the relative prominence of an organism as an agent responsible for nosocomial infections.

Evaluation of the efficacy of a 3.2% glutaraldehyde product for disinfection of fibreoptic endoscopes with an automatic machine.

The efficacy of 'Cidex Plus' 3.2% alkaline glutaraldehyde was evaluated for the disinfection of fibreoptic endoscopes. The glutaraldehyde concentration in 'Cidex Plus', stored in an automatic machine (Olympus EW-20), remained higher than 2% (2.21%) even after a total of 102 disinfection cycles during 28 consecutive days. The results of the in-vitro study on antimicrobial activity showed that this alkaline glutaraldehyde product had a greater activity against 20 test organisms, including vegetative bacteria, bacterial spores, mycobacteria, and fungi, than 2% glutaraldehyde alone. The presence of 10 or 30% human serum did not appear to affect the activity of glutaraldehyde adversely. Instrument samples made from a variety of materials such as stainless steel, glass, teflon, etc. were not damaged after 168 h of immersion in alkaline glutaraldehyde, although it contained approximately 1.7 times more glutaraldehyde than 2% glutaraldehyde alone. Based on these results, 3.2% alkaline glutaraldehyde is considered to be a more effective disinfectant for fibreoptic endoscopes, with the use of an automatic machine, than 2% glutaraldehyde.

Glutaraldehyde for electron microscopy: a practical investigation of commercial glutaraldehydes and glutaraldehyde-storage conditions.

The paper takes issue with the use by glutaraldehyde suppliers of the term 'for electron microscopy', and the common practice of researchers giving insufficient or no data about the glutaraldehyde they use. Investigation of 11 commercial glutaraldehydes recommended for electron microscopy shows that only three or four of them are adequate for this purpose, using criteria set forth in papers dated between 1965 and 1989. The present paper reports that a check of purity can best be done by spectrophotometry. The 234/280 or 235/280 nm absorbance ratio is a precise indicator of the degree of polymerization, provided certain conditions stated in this paper are fulfilled. Some of the storage precautions taken by, or proposed by, suppliers are superfluous, and only mask the inadequate purification by the suppliers. A simple protocol for the storage of stock solutions is given. Alkaline glutaraldeyhyde is inherently very unstable, even in the refrigerator. Fixatives should, therefore, be stored in the freezer or should be freshly prepared.

Normas técnicas en las endoscopias digestivas, para la prevención del síndrome de inmunodeficiencia adquiridaa y de las hepatitis virales / Technical standards for gastrointestinal endoscopy to prevent AIDS and viral hepatitis infection

Los pacientes con el síndrome de inmunodeficiencia adquirida (SIDA), al igual que los de hepatitis virales, con frecuencia presentan síntomas gastrointestinales que requieren de la atención gastroenterológica con utilización de técnicas invasivas. Debido a que en la manipulación el personal que las realiza se pone en contacto directo con secreciones potencialmente infecciosas, nos motivaron a hacer una revisión bibliográfica donde se señalen los riesgos y precauciones de las técnicas endoscópicas en estos pacientes. Se relacionan las normas para desinfectar los equipos de endoscopias y del personal que trabaja con material potencialmente infectado por el virus VIH y virus de la hepatitis B,C y delta y la propiedad de algunas sustancias oara inactivar a estos virus (AU)

Normas técnicas en las endoscopias digestivas, para la prevención del síndrome de inmunodeficiencia adquiridaa y de las hepatitis virales / Technical standards for gastrointestinal endoscopy to prevent AIDS and viral hepatitis infection

Los pacientes con el síndrome de inmunodeficiencia adquirida (SIDA), al igual que los de hepatitis virales, con frecuencia presentan síntomas gastrointestinales que requieren de la atención gastroenterológica con utilización de técnicas invasivas. Debido a que en la manipulación el personal que las realiza se pone en contacto directo con secreciones potencialmente infecciosas, nos motivaron a hacer una revisión bibliográfica donde se señalen los riesgos y precauciones de las técnicas endoscópicas en estos pacientes. Se relacionan las normas para desinfectar los equipos de endoscopias y del personal que trabaja con material potencialmente infectado por el virus VIH y virus de la hepatitis B,C y delta y la propiedad de algunas sustancias oara inactivar a estos virus

Glutaraldehyde crosslinking of collagen: effects of time, temperature, concentration and presoaking as measured by shrinkage temperature.

Experiments were carried out to study the effect on the degree of crosslinking of: (a) short term (1 or 5 min) high (50 degrees C) temperature glutaraldehyde (GA) fixation of native collagen membrane, (b) a combination of GA presoaking at low temperature [0 degree C or room temperature (rt)] followed by short time (< 3 min) heating of synthetic collagen fleece in a multilayer diffusion model. As a measure for the degree of crosslinking the shrinkage temperature (Ts) was determined. Short time (1 or 5 min) high temperature (50 degrees C) fixation using 0.1% GA solution caused the shrinkage temperature to increase to 80% and 93% respectively, of the maximum attainable Ts employing GA crosslinking (ca 91 degrees C). Fixation with 0.01% GA for 5 min at 50 degrees C appeared equally as effective as 1 min with 0.1% GA. Although an elevated fixation temperature (from rt to 45 degrees C) was found to produce a substantial increase in Ts of the collagen sheets, a homogeneous distribution of cross links was not obtained by this method. Presoaking the samples at rt (1 h) or at 0 degree C (3 h) with subsequent short time heating to 45 degrees C caused an almost equal rise in shrinkage temperature in Ts throughout the collagen samples.