Australasian Dentist Magazine March April 2021

Category 42 Australasian Dentist high potential for promotion of microbial resistance. 18 However, there is a range of alternative non-microbial ‘natural agents’ that have antimicrobial activity and the effectiveness of plant extracts, such as bacteriocins, defence peptides and phenolics has been demonstrated. 19-21 Polyphenolic plant derivatives, which are part of a plant’s natural defence mechanisms against viral and bacterial pathogens, have been the main focus of investigation. In addition to greater antimicrobial activity and improved safety profiles, there is also a perception that natural agents may be more acceptable to patients. Although the scientific evidence is unclear, there is a view that natural agents may be less likely to promote the development of resistance. 18 Many of the ‘natural’ antimicrobials have the added advantage that they may be used in aqueous solution, removing the need for inclusion of alcohol in therapeutic preparation. Citrox ® is an antimicrobial whose components are based on soluble bioflavonoids derived from citrus fruits. Bioflavonoids are hydroylated phenolic structures synthesised by plants and have previously been shown to have activity against bacteria, fungi and viruses. 22-25 Citrox ® BC and Citrox ® MDC formulations both contain bioflavonoids with the former comprising of a blend of bioflavonoids with small amounts of malic and citric acids, designed to be primarily anti-bacterial. Citrox BC is present in OralClens ® mouthrinse and toothpaste, while MDC is currently used in a range of sanitising products for surface disinfection. The aim of the present study was to determine the antimicrobial activity of these two Citrox ® formulations against a variety of bacterial species encountered in the mouth, including those implicated in periodontal disease, and a range of candidal species. The formulations would be assessed against the test strains in planktonic state and within in vitro-generated biofilms. Methods Preparation of microorganisms A total of eight bacterial species and six fungal species (Table 1) were used to evaluate the Citrox ® formulations. All bacteria were initially cultured on Fastidious Anaerobic Agar (FAA) supplemented with 5% defibrinated sheep blood (TCS Biosciences Ltd., Buckingham, UK) and then, before use in experiments, in Brain-Heart Infusion (BHI) broth. Candida species were cultured on Sabouraud’s dextrose agar (SDA) and subsequently in liquid Sabouraud’s medium. All media, unless otherwise stated, was obtained from Lab M™ (International Diagnostics Group plc, Bury, UK). Candida isolates and the two streptococcal species were maintained at 37ºC under aerobic conditions, whereas the remaining six species of bacteria were grown in an anaerobic environment (10% v/v CO2, 20% v/v H2, 70% v/v N2) at 37°C. clinical