In Vitro Bactericidal and Virucidal Efficacy of Povidone-Iodine Gargle/Mouthwash Against Respiratory and Oral Tract Pathogens

Abstract

IntroductionRecent virus epidemics and rising antibiotic resistance highlight the importance of hygiene measures to prevent and control outbreaks. We investigated the in vitro bactericidal and virucidal efficacy of povidone-iodine (PVP-I) 7% gargle/mouthwash at defined dilution against oral and respiratory tract pathogens.MethodsPVP-I was tested against Klebsiella pneumoniae and Streptococcus pneumoniae according to bactericidal quantitative suspension test EN13727 and against severe acute respiratory syndrome and Middle East respiratory syndrome coronaviruses (SARS-CoV and MERS-CoV), rotavirus strain Wa and influenza virus A subtype H1N1 according to virucidal quantitative suspension test EN14476. PVP-I 7% gargle/mouthwash was diluted 1:30 with water to a concentration of 0.23% (the recommended concentration for “real-life” use in Japan) and tested at room temperature under clean conditions [0.3 g/l bovine serum albumin (BSA), viruses only] and dirty conditions (3.0 g/l BSA + 3.0 ml/l erythrocytes) as an interfering substance for defined contact times (minimum 15 s). Rotavirus was tested without protein load. A ≥ 5 log10 (99.999%) decrease of bacteria and ≥ 4 log10 (99.99%) reduction in viral titre represented effective bactericidal and virucidal activity, respectively, per European standards.ResultsPVP-I gargle/mouthwash diluted 1:30 (equivalent to a concentration of 0.23% PVP-I) showed effective bactericidal activity against Klebsiella pneumoniae and Streptococcus pneumoniae and rapidly inactivated SARS-CoV, MERS-CoV, influenza virus A (H1N1) and rotavirus after 15 s of exposure.ConclusionPVP-I 7% gargle/mouthwash showed rapid bactericidal activity and virucidal efficacy in vitro at a concentration of 0.23% PVP-I and may provide a protective oropharyngeal hygiene measure for individuals at high risk of exposure to oral and respiratory pathogens.FundingMundipharma Research GmbH & Co. KG (MRG).

Fear and Practice Modifications among Dentists to Combat Novel Coronavirus Disease (COVID-19) Outbreak

“…At present there is no available evidence addressing the effects of commonly used antimicrobial mouth rinses on COVID 19. Hence, this recommendation could be based on the fact that gargling has been reported to decrease the viral load and spread by removing oropharyngeal protease and associated viral replication [29]. In addition, mouthwashes containing agents with anti-viral activity such as povidone-iodine have exhibited effectiveness against various respiratory viruses [30,31].…”

Guidelines for dental care provision during the COVID-19 pandemic

“…2. Using 0.23% povidone-iodine mouthwash for at least 15 s before the procedure can reduce the viral load in the patient's saliva (Eggers et al, 2018).…”

Consideration of povidone-iodine as a public health intervention for COVID-19: Utilization as “Personal Protective Equipment” for frontline providers exposed in high-risk head and neck and skull base oncology care

“…0.001%). A detailed review of its virucidal activity against a wide range of common viruses, including SARS-CoV and MERS-CoV coronaviruses, is beyond the scope of this article [6]. As a word of caution, in vitro studies using 10% and 5% PVP-I have demonstrated cilotoxicity on human respiratory cells [7].…”

“…However other investigations demonstrate continued virucidal effects of diluted PVP-I concentrations, without evidence of respiratory cilia toxicity, diminished olfactory function, or changes in mucosal appearance [8]. In vitro studies of 0.23% PVP-I mouthwash (1:30 dilution) can inactivate both SARS-CoV and MERSCoV following a 15-second exposure [6]. Though rare, prolonged use of topical 10% PVP-I solution (weeks-months) may increase the risk of iodine toxicity [9].…”