Clinical evaluation of ColdSpor, a glutaraldehyde-phenolic disinfectant.

UNLABELLED: Disinfecting solutions may vary in concentration and bactericidal activity with use, may have subjectively unpleasant characteristics, and may affect the appearance and physical condition of the equipment processed. We evaluated the high-level disinfectant ColdSpor (0.5% glutaraldehyde, 0.025% ortho-phenylphenol, and 0.005% para-tertiary amylphenol) by using it as the disinfecting agent in the processing of equipment for a large respiratory care service. MATERIALS & METHOD: The type and quantity of equipment disinfected and the physical condition of the equipment were observed and recorded. Samples of the disinfectant solution were analyzed each week, and the antimicrobial activity of the solution was tested against clinical isolates and test cultures of Pseudomonas aeruginosa. The odor of the solution and ease of use were subjectively evaluated by two equipment-processing technicians. RESULTS: More than 2,400 pieces of respiratory equipment were passed through the disinfectant solution during the 30-day study period. No changes in the appearance of the equipment were noted. Analysis revealed that 71% or more of the antimicrobial chemicals remained in the solution. Clinical isolates and test cultures of P aeruginosa showed no growth when cultured with samples of the solution in use up to 30 days. The two technicians subjectively judged the solution to have no noticeable odor and to produce no burning of the eyes. CONCLUSION: The concentration of components of the glutaraldehyde-phenolic solution maintained bactericidal activity for as long as 30 days. The solution produced no apparent physical change in equipment and was subjectively acceptable to those processing equipment.

Culture age and drying time as variables of the AOAC Sporicidal Test.

In the United States, the AOAC Sporicidal Activity of Disinfectants Method 966.04 is the standard for identifying a liquid chemical germicide as a sterilant. Furthermore, the highest level of a disinfectant must also be a sterilant as defined by Method 966.04, when used in its sterilant mode for a longer exposure time. The AOAC Sporicidal Test is also used as a part of the standard test methods to define a sterilant for Australia and the European Union. Many laboratories have identified variables of this test that can affect the sterilization exposure time for sterilants, or even the ability to classify a chemical as a sterilant. Method 966.04 requires spore-labeled porcelain penicylinders (cylinders) and silk suture loops, collectively referred to as carriers, to be dried for 24 h, but allows these carriers to be used for at least 7 days, in effect allowing a drying time of 24 h to at least 7 days. We tested the resistance of cylinders that had been labeled with Bacillus subtilis spores cultured for 72, 96, and 120 h, and dried for 24, 48, and 72 h against a 60 min exposure to 2.0% alkaline glutaraldehyde, and 2, 5, 10, 15, and 20 min exposures to 2.5N HCl. All the culture incubation and drying times met the standard of resistance to 2.5N HCI for at least 2.0 min at 20 degrees C, and all carriers contained at least 10(5) colony-forming units (CFU) of B. subtilis per carrier. However, for 3 repeated tests, regardless of incubation time, an average of 96% of the carriers were sterilized by the 2.0% glutaraldehyde after drying for 24 h, and an average of 61 % were sterilized after drying for 48 or 72 h. We propose that the variable of drying time be eliminated from Method 966.04.

A system approach to patient-safe rigid and flexible endoscopes: a microbiologist's point of view.

Many scientists have written at length on the myth of surgical sterility, and tried to shift focus from definitions of sterility and disinfection driven by artificial microbiological models to the really meaningful consideration of the patient-safe condition of medical equipment and/or products. J. C. Kelsey said it very well: "Although sterility is in theory an absolute term, in practice it may only be regarded as at best relative and at worst misleading. It is a philosophical concept that can never be unequivocally demonstrated in a real world. Experience has shown that it is virtually impossible, even if it is honest, to change the definition of a term that has been in use for many years; we may need a new term to indicate 'the state of having been sufficiently freed from microorganisms to be deemed safe for some special purpose by some competent body.' The abandonment of the term 'sterility' and the acceptance of some other term would remove confusion and enable the important matter of providing microbiologically safe medical products to be more rationally and realistically considered." The most practical way to produce a patient-safe endoscope is through a careful consideration of the whole processing system as discussed in this article, not by focusing strictly on the differences between high-level disinfectants and sterilants. A sterilant used within a poorly designed processing system could actually result in an unsafe, even microbiologically dangerous, endoscope. On the other hand, high-level disinfectants used within a well-designed and quality-controlled process can and do produce safe, even sterile, endoscopes.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis and optimization of a quantitative organic soil neutralization test for disinfectants.

An analysis and optimization of a test to quantitatively assess the resistance of disinfectants to neutralization by organic soil is presented. The recommended method uses sterile, dry baker's yeast as a standard organic soil and 24-hr cultures of Staphylococcus aureus and Pseudomonas aeruginosa as test organisms. The test determines the maximum per cent (w/v) of organic soil which a disinfectant can tolerate and remain able to kill about 106 test organisms/ml in 10 min at 25 degrees C. This per cent is defined as the organic soil neutralization number. The procedure offers several advantages over other organic soil capacity tests.

Intraperitoneal injection of mice.

Steward, Ornellas, Beernink, and Northway (2) reported a 14% error in the placement of intraperitoneal injections of mice. They considered this error inherent in the technique and not simply correctable. We similarly found an error in the intraperitoneal injection of mice and attempted to identify the cause of error by varying such technical procedures as size of needle, site of penetration (through lower left versus lower right quadrant), investigator, angle of needle to the abdominal wall, and speed of injection. None of these technical modifications consistently eliminated or reduced the error of placement.

Identification of possible artifacts in the association of official analytical chemists sporicidal test.

Two laboratories tested four different brands of alkaline 2% glutaraldehyde sterilants by the Association of Official Analytical Chemists sporicidal test. Each laboratory found survival of Clostridium sporogenes spores on spore-labeled unglazed porcelain penicylinders (cylinders) to vary from test to test, and survival did not always correlate with increasing sterilant exposure time. These results were consistent with a theory that there may be random conditions within the test that prevent the sterilant from contacting all spores. Further studies indicated that the prior history of the unglazed porcelain cylinders and whether the C. sporogenes culture grown in egg-meat media had been processed (homogenized) to eliminate visible pieces of egg-meat media were important factors affecting the results and repeatability of this test.

Antimicrobial and other properties of a new stabilized alkaline glutaraldehyde disinfectant/sterilizer.

The properties of stabilized alkaline 2% glutaraldehyde solution (SGS) are discussed. SGS is discussed with regard to its chemistry, antimicrobial properties, organic soil resistance, toxicity, corrosivity and chemical stability. SGS retains the maximum antimicrobial activity of alkaline glutaraldehyde solutions and the chemical stability heretofore observed only with acidic glutaraldehyde solutions. These improvements, along with the inherent resistance of glutaraldehyde to neutralization by organic soil, allow SGS to be continuously used for 14 days in situations of high dilution, or 28 days in situations of low dilution.