Efficacy of Glucoprotamin containing disinfectants against different species of atypical mycobacteria

Equal Efficacy of Glucoprotamin and an Aldehyde Product for Environmental Disinfection in a Hematologic Transplant Unit: A Prospective Crossover Trial

Background.

The inanimate hospital environment has emerged as an important reservoir of nosocomial pathogens. In particular, multidrug-resistant pathogens, such as methicillin-resistant Staphylococcus aureus, Acinetobacter species, and Clostridium difficile, play a major role in the transmission of hospital-acquired infections. In Europe, aldehydes, chlorine, and quaternary ammonium compounds have been commonly used for environmental disinfection. Glucoprotamin, a newer active compound for disinfectants, has been clinically tested for disinfection of instruments but not for environmental disinfection.

Objective.

This study evaluated the antimicrobial effectiveness of a glucoprotamin-containing product (Incidin) compared with that of an aldehyde-containing product (Deconex), the current standard at our institution.

Methods.

This prospective crossover study was conducted in our access-restricted hematologic transplant unit. A total of 3,086 samples from the environment were processed and examined for overall bacterial burden as well as selectively for S. aureus, C. difficile, and gram-negative bacteria.

Results.

There was no significant difference in residual bacteria after disinfection between the 2 products in terms of overall burden and selected pathogens. Enterococci were the predominant pathogens recovered from surfaces, but no vancomycin-resistant enterococci were recovered. Similarly, C. difficile could not be found in the patients' environment, even in rooms, despite the use of selective media.

Conclusion.

The aldehyde-containing product (Deconex) and the glucoprotamin-containing product (Incidin) demonstrated similar efficacy against environmental contamination in a hematologic transplant unit with the application of selective media for C. difficile, S. aureus, and gram-negative bacteria in addition to standard medium.

Surface-Dried Viruses Can Resist Glucoprotamin-Based Disinfection

Touching of contaminated objects and surfaces is a well-known method of virus transmission. Once they are attached to the hands, viruses can easily get adsorbed and initiate infection. Hence, disinfection of frequently touched surfaces is of major importance to prevent virus spreading. Here we studied the antiviral activity of a glucoprotamin-containing disinfectant against influenza A virus and the model virus vaccinia virus (VACV) dried on inanimate surfaces. The efficacy of the surface disinfectant on stainless steel, polyvinyl chloride, and glass coupons was investigated in a quantitative carrier test. Vacuum-dried viruses were exposed to 0.25%, 0.5%, and 1% disinfectant for 5 min, 15 min, and 30 min without agitation, and residual infectivity was determined by endpoint titration. Although glucoprotamin was highly active against both viruses in suspension, limited antiviral activity against the surface-dried viruses was detected. Even after 30 min of exposure to 1% disinfectant, VACV was not completely inactivated. Furthermore, influenza A virus inactivation was strongly affected by the surface composition during the 5-min and 15-min treatments with 0.25% and 0.5% disinfectant. The results presented in this study highlight the relevance of practical tests to assess the antiviral activity of surface disinfectants. High virucidal activity in solution is not necessarily indicative of high antiviral activity against surface-dried viruses. In addition, we want to emphasize that the mere exposure of surfaces to disinfectants might not be sufficient for virus inactivation and mechanical action should be applied to bring attached viruses into contact with virucidal compounds.

The influence of laboratory adaptation on test strains, such as Pseudomonas aeruginosa, in the evaluation of the antimicrobial efficacy of ortho-phthalaldehyde

The microbiocidal efficacy of 0.55% ortho-pthalaldehyde (OPA) was evaluated in a rough carrier test, using more than 200 strains of bacteria and yeasts from patients and reference ATCC strains. This test was then compared with the European carrier test (prEN14561) using Pseudomonas aeruginosa. We also sought to determine whether recently isolated P. aeruginosa had the same susceptibility to OPA, after laboratory adaptation. It was shown that P. aeruginosa was less susceptible to OPA (being reduced by a factor of 10(3.8)) than the other strains (reduced by a factor of 10(4)). The surface test used, produced a lesser reduction of P. aeruginosa than the European test. For recently isolated strains (N = 66), the rough model demonstrated that the number of survivors increased both quantitatively and qualitatively from day one to day seven. It was concluded that disinfectant efficacy should be confirmed with recently isolated organisms.

Antimicrobial activity of glucoprotamin: a clinical study of a new disinfectant for instruments

OBJECTIVE

To determine the in vitro efficacy of glucoprotamin for the disinfection of instruments.

DESIGN

Prospective observational study.

SETTING

University women's hospital.

METHODS

Instruments were immersed in saline solution after use, and glucoprotamin was added to a concentration of 1.5% before soaking for 60 minutes. Biocidal activity was determined by the difference in colony-forming units (CFU) on instruments before and after disinfection.

RESULTS

One hundred thirty-seven instruments were collected during 10 days and exposed to a 1.5% dilution of glucoprotamin without prior washing. Bioburden before disinfection ranged from 2 x 10(5) to 7.1 x 10(7) CFU per instrument. Average bacterial killing was 5.98 log10 CFU +/- 0.48 under aerobic conditions and 6.75 log10 CFU +/- 0.54 under anaerobic conditions, despite the presence of large amounts of proteins on instruments that were frequently bloody. No vegetative bacteria were isolated in any sample after disinfection.

CONCLUSION

This clinical study confirmed excellent in vitro efficacy of glucoprotamin without prior removal of proteins and debris.

Comparison of the mycobactericidal activity of ortho- phthalaldehyde, glutaraldehyde and other dialdehydes by a quantitative suspension test

The mycobactericidal activity of various dialdehydes has been assessed by a quantitative suspension test in both 'clean' and 'dirty' conditions. Test organisms consisted of glutaraldehyde (GTA)-sensitive strains of Mycobacterium chelonae NCTC 946, M. abscessus NCTC 10882, two GTA-resistant M. chelonae strains and M. terrae NCTC 10856 (a proposed M. tuberculosis surrogate). The aldehydes tested were a new high-level disinfectant, ortho-phthalaldehyde (OPA) at 0.5% (v/v) unadjusted pH 6.5 and pH 8, GTA at 0.5% (v/v) pH 8, glyoxal at 0.5% (v/v) pH 8 and 10% (v/v) unadjusted pH 2.8, malonaldehyde sodium salt (NaMDA) at 0.5% (w/v) pH 8 and 10% (w/v) unadjusted pH 7.5 and succinaldehyde at 0.5% (v/v) pH 8. Results showed that 0.5% acidic and alkaline OPA were rapidly mycobactericidal, under both 'clean' and 'dirty' conditions, and more importantly were active against GTA-resistant strains. The washer disinfector isolates of M. chelonae were, as expected, extremely resistant to 0.5% GTA which was slowly mycobactericidal against the other strains. Glyoxal, NaMDA and succinaldehyde were ineffective against all the strains investigated. However, a high concentration of glyoxal exhibited a slow mycobactericidal activity except with M. terrae NCTC 10856, but this was not observed with NaMDA. This evaluation, using a quantitative suspension test based on a European standard, supported the claim that OPA is an effective choice as a high-level disinfectant for medical devices.