Interaction of povidone-iodine compounds, phagocytic cells, and microorganisms

Abstract

The interaction between povidone-iodine, phagocytic cells, and microorganisms was studied. Three preparations of povidone-iodine were investigated: commercially available povidone-iodine solution Betadine, pure high-molecularweight povidone-iodine as used in Betadine, and a low-molecular-weight povidone-iodine. Low concentrations of povidone-iodine (-0.005%) have considerable activity in vitro. The concentrations used clinically (0.1 to 20%) are toxic for granulocytes and monocytes. Leukocytes reduce the in vitro microbicidal activity of povidone-iodine. No differences of any importance were found between the three preparations of povidone-iodine.Povidone-iodine (polyvinylpyrrolidone-iodine) is a potent microbicidal drug. It is used for several purposes: prophylactically for disinfection (3), irrigation of surgical wounds (4, 8), and bladder irrigation in patients with urinary catheters (6) and therapeutically in infections of the peritoneal and pleural cavities (5, 7) and cutaneous candidiasis (9). Thus, povidone-iodine is applied not only to the surface of the body, but also in tissues and body cavities, where its interaction with phagocytic cells can be of importance because these cells are involved in the host defense against infection. Povidone-iodine can influence the function of such cells, since it is known to reduce chemotaxis (2). Since nothing was known about the effect of povidoneiodine on phagocytosis and intracellular killing or about the influence exerted by cells or tissue on the microbicidal activity of povidone-iodine, this quantitative study was performed to investigate possible interactions between povidoneiodine, leukocytes, and microorganisms. MATERIALS AND METHODSThe materials and methods used for preopsonization and the phagocytosis and intracellular killing assay have been described in detail elsewhere (10). Here, only the bactericidal agents are referred to, and the methods are briefly described.Povidone-odine. Betadine. Solutions of Betadine were made by diluting the commercially available Betadine (10o solution of the high-molecular-weight povidone-iodine PVPK30-J in water; Dagra N.V., Diemen, The Netherlands) in phosphate-buffered saline. The available iodine is about 10%6. PVPK30-J. PVPK30-J is a povidone-iodine compound prepared with the high-molecular-weight povidone PVPK30 and iodine. The available iodine in this preparation is 11.2%. Solutions were made by dissolving the substances in phosphate-buffered saline.PVPK17-J. PVPK17-J is prepared with the lowmolecular-weight povidone PVPK17 and iodine. The available iodine in this compound is 11.4%. Solutions were made by dissolving the substance in phosphatebuffered saline.Iodine. Solutions of iodine were made by diluting iodine 1% (wt/vol) in 70%o (vol/vol) ethanol in phosphate-buffered saline.Mkroorganisms. The bacteria used for the study were cultured at 37C overnight in nutrient broth no. 2 (Oxoid Ltd., London, England). Candida albicans was cultured for 5 days at 30°C in nutrient broth no. 2 containing 1% (wt/vol) glucose. After...

The Effect of Intravitreally Injected Povidone-Iodine onStaphylococcus epidermidisin Rabbit Eyes

“…18 Further studies demonstrate that 0.005% or higher concentrations are necessary to kill certain strains of bacteria, such as S. aureus. 19 The authors questioned, however, whether or not this would be reproducible in vivo. The maximally effective range of PVP-I appears to be between 0.1% and 5%, with these concentrations being even more effective than the stock 10% solution.…”

Silver colloid dressings score over conventional dressings in diabetic foot ulcer: a randomized clinical trial

“…On the other hand, use of iodine preparations have been criticized because povidoneiodine, unless highly diluted, is toxic to most cell types and implicates in healing process. 34 The Contop trial evaluated 352 chronic non-healing ulcers in which venous leg ulcers were present in 43-48%, mixed venous/arterial in 20-24%, pressure ulcers in 10% and diabetic foot ulcers in 5-9%. The primary dressing type consisted of a foam or alginate in 45%, hydrocolloid or film in 15%, gauze in 4%, antimicrobial in 30% (silver foam in 48% of these) and a range of other dressings in the remaining 6%.…”

An Asian Perspective on Povidone Iodine in Wound Healing

“…There have been concerns about perceived cytotoxicity with PVP-I, and the potential detrimental effect of PVP-I on wound healing has been widely argued, with several in vitro studies demonstrating the dose-dependent cytotoxicity of PVP-I on cultures of granulocytes, monocytes, keratinocytes, and fibroblasts [6,62,63] . At the same time, questions have been raised on the clinical relevance and application of these in vitro reports of topical toxicity or impact on wound healing [30,33,62] .…”