Bactericidal effect of γ-radiation with 137Cesium in platelet concentrates

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.

Treatment of platelet concentrates and plasma with riboflavin and UV light: Impact in bacterial reduction

OBJECTIVES

Transfusion of hemocomponents is essential for clinical and surgical procedures and therefore their safety has increased. An option for pathogen reduction includes the combination of riboflavin and UV light. To our knowledge, there are no studies in Latin America that demonstrate the effectiveness of the pathogen reduction in hemocomponents. The objective of this work was to evaluate the efficiency of a pathogens reduction system in platelets concentrates (PC) and plasma.

MATERIALS AND METHODS

PC and plasma were contaminated with Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes and Staphylococcus epidermidis at 10⁴ to 10⁶ CFU and subjected to bacterial reduction. After bacterial reduction, hemocomponents were subjected to cultivation of surviving bacteria by automated method and classical colonies quantification. Additionally, quality control testing was performed in order to confirm the integrity of platelets and coagulation laboratory values in plasma before and after bacterial reduction.

RESULTS

The bacterial death in PC/plasma was expressed by Logarithmic Reduction Value as follows: for both strains (E. coli and S. pyogenes) 4/4, 5/5 and 6/6; for K. pneumoniae 2.54/2.23, 2.94/2.22 and 3.44/2.98, for S. epidermidis 4/4, 3.11/5 and 3.23/4.19, for 10⁴, 10⁵ and 10⁶ CFU, respectively. In PC and plasma, platelet count, pH (at 22°C), activated partial thromboplastin time (aPTT), prothrombin time (PT), fibrinogen, factor VIII and total proteins (TP) were slightly modified.

CONCLUSIONS

UV light with riboflavin is able to reduce an important number of pathogens in hemocomponents; however, the bacterial reduction is influenced by the nature and quantity of the pathogen.