Reusable surface disinfectant tissue dispensers are used in hospitals in many countries because they allow immediate access to pre-soaked tissues for targeted surface decontamination. On the other hand disinfectant solutions with some active ingredients may get contaminated and cause outbreaks. We determined the frequency of contaminated surface disinfectant solutions in reusable dispensers and the ability of isolates to multiply in different formulations. Reusable tissue dispensers with different surface disinfectants were randomly collected from healthcare facilities. Solutions were investigated for bacterial contamination. The efficacy of two surface disinfectants was determined in suspension tests against two isolated species directly from a contaminated solution or after 5 passages without selection pressure in triplicate. Freshly prepared use solutions were contaminated to determine survival of isolates. 66 dispensers containing disinfectant solutions with surface-active ingredients were collected in 15 healthcare facilities. 28 dispensers from nine healthcare facilities were contaminated with approximately 107 cells per mL of Achromobacter species 3 (9 hospitals), Achromobacter xylosoxidans or Serratia marcescens (1 hospital each). In none of the hospitals dispenser processing had been adequately performed. Isolates regained susceptibility to the disinfectants after five passages without selection pressure but were still able to multiply in different formulations from different manufacturers at room temperature within 7 days. Neglecting adequate processing of surface disinfectant dispensers has contributed to frequent and heavy contamination of use-solutions based on surface active ingredients. Tissue dispenser processing should be taken seriously in clinical practice.
To evaluate the reproducibility and workability of the in vivo test model of the European test standard EN 12791 regarding the effectiveness of surgical hand antiseptics and, as a secondary objective, to evaluate the power of the model to discriminate between the effectiveness of various formulations of surgical hand antiseptics.Prospective, randomized, multicenter study with a Latin square design.Five laboratories at 2 universities, 2 disinfectant manufacturers, and 1 private testing institution.Twenty healthy adults in each laboratory.Surgical hand antisepsis was performed by scrubbing with chlorhexidine gluconate 4% detergent (CHG) or by rubbing the hands with propan-2-OL (70% by volume; Iso 70) or ethanol 85% (E 85); rubbing the hands and forearms for 3 minutes with propan-1-OL (N 60) was used as the reference disinfection procedure. We deliberately chose to use these antiseptics at the given concentrations because they were intended to cover the range of typical antiseptics submitted for approval according to EN 12791.In once-weekly tests, the immediate effects of the 4 antiseptics were established according to the method laid down in EN 12791 by assessing the release of skin flora from the fingertips as viable bacteria counts per milliliter of sampling fluids before treatment and viable bacteria counts immediately after treatment, separately for both hands, such that after 4 weeks each volunteer had used every formulation once.The mean log reduction factor (RF) for the release of bacterial skin flora (the log RF was calculated as the log count before treatment minus the log count after treatment) and corresponding standard deviations for the 4 hand antisepsis formulations were as follows: for CHG, 1.1+/-0.3 colony-forming units (cfu) per milliliter of sampled fluid; for Iso 70, 1.7+/-0.3 cfu/mL; for E 85, 2.1+/-0.3 cfu/mL; and for N 60, 2.4+/-0.4 cfu/mL. The differences between these values proved significant (P<.001) by analysis of variance and in Tukey's "honestly significantly different" (HSD) post hoc test. Although, with regard to their immediate antibacterial activity, the same ranking of these antiseptics was found at all laboratories, the levels of efficacy were significantly different across laboratories (P<.001); no statistical difference was found between left and right hands (P>.01). Relating the log RF values of the other 3 formulations to those of the reference formulation (N 60) abolished differences between laboratories (P=.16); in addition, the interclass correlation coefficient decreased from 9.1% to 4.5%. With 20 volunteers, a minimum difference of 0.47 log between the mean log RFs of the reference formulation and an inferior test formulation will be detected as significant at an alpha of .05 (1-sided) and a 1- beta value of .8.The test method described in EN 12791 yielded the same conclusion on the effectiveness of the tested formulations in every laboratory and proved, therefore, reproducible and workable.
Reusable surface disinfectant (SD) tissue dispensers are used in hospitals in many countries because they allow immediate access to soaked tissues for targeted surface decontamination.
There is a trend in some countries to recommend the use of surgical hand disinfectants at volumes as low as 4 ml per application.To determine whether the volume applied and hand size influence the efficacy of surgical hand disinfection.Thirteen experiments, according to EN 12791, resulting in 269 datasets from 75 subjects were analyzed. Hands were first washed for one minute with soap. The pre-values were obtained by rubbing the finger tips in tryptic soy broth for one minute. Each subject treated his/her hands with n-propanol (60%, v/v), with as many portions as necessary to keep the hands wet for three minutes (6-12 ml). Bacterial post-values were taken from one hand (immediate effect); the other hand was gloved for three hours (sizes 7-9). The second post-value was taken when the glove was removed (3 h effect).The mean immediate log10 reduction of CFU was 2.56 ± 1.12. The glove size had no significant effect on the efficacy of disinfection (p = 0.182; ANOVA). However, a volume of 6 ml was significantly less effective than 9 ml for glove sizes of 7.5-8 (p < 0.05; Tukey post hoc analysis). The mean log10 reduction after 3 h was 2.12 ± 1.24. A volume of 6 ml was again significantly less effective than 12 ml for glove size 7 and than 9 ml for glove sizes 7.5-8 (p < 0.05).The application of small volumes of surgical hand disinfectant when using the EN 12791 reference procedure is likely to yield poor efficacy results, regardless of hand size.
