Antimicrobial efficacy of alternative compounds for use in oral care toward biofilms from caries‐associated bacteria in vitro

Abstract

For caries‐active patients, antimicrobial measures may be useful in addition to mechanical biofilm removal. The aim of this study was to investigate the antimicrobial efficacy of alternative compounds for use in oral care from two main categories (i.e., preservatives and natural compounds) toward biofilms from caries‐associated bacteria as compared to oral care gold‐standards chlorhexidine digluconate ( CHX ), cetylpyridinium chloride ( CPC ), and zinc. Compounds were screened in initial Streptococcus mutans biofilms. Then, the most effective compounds were further investigated in mature S. mutans and polymicrobial biofilms comprising Actinomyces naeslundii , Actinomyces odontolyticus, and S. mutans . Here, distinct treatment periods and concentrations were evaluated. Biofilms were visualized by scanning electron microscopy and bacterial membrane damage was evaluated by means of flow cytometry and staining with SYBR Green and propidium iodide. Citrus extract was the only compound exhibiting similar antimicrobial efficacy in initial S. mutans biofilms (>5 log 10 ) as compared to CHX and CPC , but its effect was clearly inferior in mature S. mutans and polymicrobial biofilms. Flow cytometric data suggested that the mechanism of antimicrobial action of citrus extract may be based on damage of bacterial membranes similar to CHX and CPC . From all alternative compounds investigated in this study, citrus extract exhibited the highest antimicrobial efficacy toward in vitro biofilms from caries‐associated bacteria, but still was less effective than oral care gold‐standard antiseptics CHX and CPC . Nevertheless, citrus extract may be a valuable antimicrobial compound for use in oral care for caries‐active patients.

Spontaneously Arising Streptococcus mutans Variants with Reduced Susceptibility to Chlorhexidine Display Genetic Defects and Diminished Fitness

“…A similar finding was recently made in S. mutans, where vesicle-like structures were apparent on the cell surface after treatment with 0.2% CHX (11). In the same study, treatment of 72-h S. mutans biofilms resulted in 80% of the population displaying loss of membrane integrity, assessed by staining with propidium iodide (PI) and analysis of the population using flow cytometry (11).…”

“…The authors posited that the structural changes of the bacterial cell wall may be due to the action of CHX with membrane cardiolipin and phosphatidylethanolamine to disturb the normal arrangement and integrity of the phospholipid bilayer structure and its associated proteins (10). A similar finding was recently made in S. mutans, where vesicle-like structures were apparent on the cell surface after treatment with 0.2% CHX (11). In the same study, treatment of 72-h S. mutans biofilms resulted in 80% of the population displaying loss of membrane integrity, assessed by staining with propidium iodide (PI) and analysis of the population using flow cytometry (11).…”

Ca2+ release and buffering effects of synthetic hydroxyapatite following bacterial acid challenge

“…The concentration of 0.5% of HAP or silica, respectively, was chosen to mimic dilution effects as they may occur in the oral cavity after using a mouthwash with 5% HAP [18]. In contrast to previous works [34,35], we used no filter-sterilized saliva here to promote biofilm formation as salivary Ca 2+ ions (concentrations between 20 and 55 μg/ mL [11,[31][32][33], as described above), may have impeded Ca 2+ release measurements.…”

Eficácia do uso de lasers ou clorexidina na redução microbiana em lesões de cárie produzidas artificialmente

“…No entanto, no mesmo artigo, os autores citam que isso poderia dificultar a interação do agente de união com a dentina. Além disso, embora eficaz, tem sido recomendado limitar o seu uso a fim de reduzir o risco de induzir resistência adquirida pela mesma ou mesmo resistências cruzadas a antibióticos (Cieplik et al, 2018).…”

“…Embora seja usada como um padrão ouro em comparação a outros agentes antimicrobianos, a clorexidina possui algumas limitações quando do seu uso prolongado como enxaguatório. (Sharma et al, 2018;Cieplik et al, 2018;Nemezio et al, 2017;Fumes et al, 2018b). Porém, a clorexidina tem boa eficácia antibacteriana, efeito bacteriostático e efeito bactericida, devido à precipitação e / ou coagulação do citoplasma (Goud S, et al 2018).…”