Evaluation of two chlorhexidine - alcohol-based skin disinfectants in blood donation setting

In situ and in vitro evaluation of two antiseptics for blood bank based on chlorhexidine gluconate/isopropyl alcohol and povidone-iodine

BACKGROUND

Poor disinfection is the main cause of blood contamination, so its elimination is key to limiting the entry of bacteria into the collection system. With the advancement of antiseptic technology, antiseptics with sterile, disposable applicators are now available.

AIM

To evaluate in situ two antiseptics (with and without applicators) for blood banks and to demonstrate in vitro antiseptic activity on bacterial biofilms of importance in transfusion medicine.

METHODS

Antiseptic A (2% sterile solution of chlorhexidine gluconate/70% isopropyl alcohol provided with applicator) and bulk antiseptic B (10% povidone-iodine) were evaluated. The deferred blood donor arms were subjected to disinfection with antiseptics A and B and the contralateral arms were cultured to determine the baseline bacterial load (control). Antiseptic activity was assessed by ANOVA and logaritmic reduction values (LRV) and percentage reduction values (PRV) were calculated. Finally, the in vitro activity of antiseptic A was analyzed by confocal laser scanning microscopy (CLSM) on biofilm models.

RESULTS

Prior to disinfection tests, commensal and clinically important bacteria were identified; antiseptic A showed post-disinfection bacterial growth rates of zero compared to controls (p < 0.0001). The frequency of bacterial growth with antiseptic B was 74%. A significant difference was identified between both antiseptics, where antiseptic A showed higher activity (p < 0.5468). LRV and PRV were 0.6-2.5/100% and 0.3-1.7/66.7-99.7% for antiseptics A and B, respectively. Through CLSM, disinfectant A (without applicator) showed lower in vitro antiseptic activity on the tested biofilms at the exposure times recommended by the manufacturer.

CONCLUSIONS

Sterile solution of chlorhexidine gluconate/isopropyl alcohol with applicator showed advantages disinfection in deferred blood donors over povidone-iodine.

Current status of rapid bacterial detection methods for platelet components: A 20-year review by the ISBT Transfusion-Transmitted Infectious Diseases Working Party Subgroup on Bacteria

BACKGROUND AND OBJECTIVES

Bacterial contamination of platelet components (PCs) poses a safety challenge for transfusion patients. Despite mitigation interventions, the residual risk of transfusion-transmitted bacterial infections remains predominant. PC safety can be improved either by pathogen reduction or by implementation of bacterial detection methods. Detection methodologies include culture methods and rapid detection methods. The current review focuses on currently available rapid detection methods.

MATERIALS AND METHODS

We reviewed published manuscripts since 2000 on rapid bacterial detection methods used for PC screening with result determination within 4 h. Methods meeting this criterion included Verax PGDprime, BacTx and nucleic amplification testing. The analytical and diagnostic sensitivity and specificity of these systems were assessed.

RESULTS

The analytical sensitivity between the different detection methods ranged between 50 and 100,000 CFU/ml. The sample volume used by these testing systems varies between 0.5 and 1.0 ml of PCs. A delay of at least 48 h before sampling enhances detectability. All rapid detection methods generate results in a timely manner, allowing testing to be performed before transfusion with optimal sensitivity.

CONCLUSION

Rapid detection methods improve PC safety regarding bacterial contamination. The assays are optimal for rapidly growing bacteria, which are more likely to cause septic transfusion reactions in patients. Because of the reduced diagnostic sensitivity, the sample collection should be late in shelf-life and ideally just before transfusion. The major benefit of these methods is that the test result can be obtained before releasing PCs for transfusion or to be used in combination with other screening methods applied early during PC storage.

Chlorhexidine alcohol versus povidone-iodine: The comparative study of skin disinfectants at the blood transfusion centers of Iran

OBJECTIVES

The skin disinfection in the blood donor's arm is a key step to minimize the risk of microbial contamination at blood donation sessions. Current study aimed to compare the efficacy of 2% chlorhexidine gluconate in 70% isopropyl alcohol (CHG/IPA) with povidone-Iodine (PI) at blood transfusion centers (BTCs) of Iran.

MATERIAL AND METHODS

Blood donors were selected to evaluate three commercial CHG/IPA disinfectants (N=300), prior the application at BTCs, and to compare the rate of positive skin cultures between CHG/IPA and PI in 31 BTCs (N=8578). The rate of positivity for PI over a 5-year period was also investigated. After application of a two-step disinfection procedure, the biochemical characteristics were checked in accordance with the conventional bacteriological methods. The Z-test analysis was used to compare the deviation between the positive microbial culture ratios.

RESULT

No donors had a positive culture after disinfection during the evaluation study. There was no difference in the rate of positivity between PI and CHG/IPA after disinfection (P>0.05). The rate of positivity for PI from 2012 to 2017 showed a decreasing trend. The rate of positivity was significantly higher in winter rather than summer (P<0.05).

CONCLUSION

The disinfection efficacy of CHG/IPA was equivalent to that of PI. The 5-year monitoring of PI at BTCs showed that the improvement in the rate of positive skin cultures possibly due to effectiveness of correcting actions.