Impact of the reduction of environmental and equipment contamination on vancomycin-resistant enterococcus rates.

More than 1,500 perirectal swab cultures and 552 environmental and equipment cultures were collected during the study period. Enterococcus faecium was the most frequent species isolated, being responsible for 71% of the positive cultures. Fifty infections were documented, with bloodstream infections (18, 36%) being the most frequent, followed by urinary tract infection (15, 30%). An educational intervention was given to 136 healthcare workers (HCWs), and a questionnaire regarding vancomycin-resistant enterococcus (VRE) transmission was also performed pre- and post-intervention. Overall, 858 opportunities of patient care were evaluated. The compliance with contact precautions did not improve; however, in general, the proportion of correct answers regarding VRE increased significantly when comparing pre- and post-intervention periods (p < 0.05). On the other hand, the proportion of environmental and equipment contaminated by VRE decreased significantly from pre- (23.2%) to post-intervention (8.2%) (p < 0.001) and was associated with a significant decrease in VRE infection from 7.7 to 1.9 when comparing the pre- and post-intervention periods. The use of vancomycin (defined daily dose [DDD]) did not change significantly over the study period (p = 0.970), and the use of teicoplanin increased (p < 0.001). Seventy-six percent of E. faecium belong to type and subtype A by pulsed-field gel electrophoresis (PFGE). This predominant type was found in the environment and caused colonization and infection. In conclusion, the present study showed that reduction of the proportion of environmental and equipment contamination was associated with a decrease of colonization and infection due to VRE, and that the strategy to control VRE dissemination should be based on local problems.

Polyphenol tannic acid inhibits hydroxyl radical formation from Fenton reaction by complexing ferrous ions.

Tannic acid (TA), a plant polyphenol, has been described as having antimutagenic, anticarcinogenic and antioxidant activities. Since it is a potent chelator of iron ions, we decided to examine if the antioxidant activity of TA is related to its ability to chelate iron ions. The degradation of 2-deoxyribose induced by 6 microM Fe(II) plus 100 microM H2O2 was inhibited by TA, with an I50 value of 13 microM. Tannic acid was over three orders of magnitude more efficient in protecting against 2-deoxyribose degradation than classical *OH scavengers. The antioxidant potency of TA was inversely proportional to Fe(II) concentration, demonstrating a competition between H2O2 and AT for reaction with Fe(II). On the other hand, the efficiency of TA was nearly unchanged with increasing concentrations of the *OH detector molecule, 2-deoxyribose. These results indicate that the antioxidant activity of TA is mainly due to iron chelation rather than *OH scavenging. TA also inhibited 2-deoxyribose degradation mediated by Fe(III)-EDTA (iron = 50 microM) plus ascorbate. The protective action of TA was significantly higher with 50 microM EDTA than with 500 microM EDTA, suggesting that TA removes Fe(III) from EDTA and forms a complex with iron that cannot induce *OH formation. We also provided evidence that TA forms a stable complex with Fe(II), since excess ferrozine (14 mM) recovered 95-96% of the Fe(II) from 10 microM TA even after a 30-min exposure to 100-500 microM H2O2. Addition of Fe(III) to samples containing TA caused the formation of Fe(II)n-TA, complexes, as determined by ferrozine assays, indicating that TA is also capable of reducing Fe(III) ions. We propose that when Fe(II) is complexed to TA, it is unable to participate in Fenton reactions and mediate *OH formation. The antimutagenic and anticarcinogenic activity of TA, described elsewhere, may be explained (at least in part) by its capacity to prevent Fenton reactions.