Oxygen tension during biofilm growth influences the efficacy antimicrobial agents

Abstract

ResumoObjetivo: Comparar a eficácia antimicrobiana de clorexidina 0,12% (CHX) e solução de chá verde (CV) (Camellia sinensis) em biofilmes formados em diferentes tensões de oxigênio em um modelo in situ. Método: Vinte e cinco estudantes de odontologia foram elegíveis. Um dispositivo com espécimes de esmalte (EE) padronizados, voltado para o palato e para vestibular foram inseridos nos voluntários por 7 dias. Durante os primeiros quatro dias nenhum agente foi aplicado. A partir do quinto dia, ambos os agentes foram aplicados nos EEs no grupo teste e nenhum agente foi aplicado no grupo EE controle. Após 7 dias, os fragmentos EEs foram removidos dos dispositivos, sonicados, plaqueados em ágar, e incubado durante 24 h a 37 °C para determinar unidades formadoras de colonias (UFCs). Resultado: CHX teve significativamente melhor eficácia em comparação com CV nos EEs para vestibular (1.330 vs. 2.170 UFC/mL) e EEs voltados para o palatal (2.250 vs. 2.520 UFC/mL). Comparações intragrupos mostraram maior eficácia em EEs vestibulares do que as EEs voltadas para o palato (1.330 vs. 2.250 UFC/mL para CHX e 2170 vs, 2520 UFC/mL para CV) em ambas as soluções. Análise dos controles, mostrou a formação de biofilme significativamente maior em comparação com EEs palatinas e bucais. Conclusão: CHX tem uma eficácia maior do que o chá verde em biofilmes formados por 4 dias. A eficácia dos agentes foi reduzida para os biofilmes em ambiente com baixa tensão de oxigênio. A tensão de oxigênio parece influenciar na eficácia dos agentes testados.Descritores: Camellia sinensis; clorexidina; placa dentária. AbstractObjective: To compare the antimicrobial efficacy of a 0.12% chlorhexidine (CHX) and herbal green tea (Camellia sinensis) solution on established biofilms formed at different oxygen tensions in an in situ model. Method: Twenty-five dental students were eligible for the study. In situ devices with standardized enamel specimens (ES) facing the palatal and buccal sides were inserted in the mouths of volunteers for a 7 day period. No agent was applied during the first four days. From the fifth day onward, both agents were applied to the test ES group and no agent was applied to the control ES group. After 7 days the ES fragments were removed from the devices, sonicated, plated on agar, and incubated for 24 h at 37 °C to determine and quantify the colony forming units (CFUs). Result: CHX had significantly higher efficacy compared to green tea on the buccal (1330 vs. 2170 CFU/µL) and palatal (2250 vs. 2520 CFU/µL) ES. In addition, intragroup comparisons showed significantly higher efficacy in buccal ES over palatal ES (1330 vs. 2250 CFU/µL for CHX and 2170 vs, 2520 CFU/µL for CV) for both solutions. Analysis of the ES controls showed significantly higher biofilm formation in palatal ES compared to buccal ES. Conclusion: CHX has higher efficacy than green tea on 4-day biofilms. The efficacy of both agents was reduced for biofilms grown in a low oxygen tension environment. Therefore, the oxygen tension environment seems to influence the eff...

Bioengineered Platforms for Chronic Wound Infection Studies: How Can We Make Them More Human-Relevant?

“…While the exact mechanisms underlining the impact of oxygen on chronic wound biofilms remains to be explored, it remains plausible that lowered oxygen tension and redox potential will favor the proliferation of polymicrobial biofilms in the wound bed (Cramer, 2014). In addition, anoxic or hypoxic conditions have been shown to reduce the efficacies of a range of antibiotics, resulting in reduced biofilm susceptibility (Schaible et al, 2012;Antoniazzi et al, 2016;Gupta et al, 2016). Further contributing to this redox state are excess levels of reactive oxygen species (ROS), which are considered to be a major cause of delayed wound healing.…”

Perbedaan Efektivitas Chlorhexidine Glukonat 0,2% Dengan Teh Hijau (Camellia Sinensis) Terhadap Jumlah Porphyromonas Gingivalis

“…Pada penelitian lain yang dilakukan oleh Antoniazzi mengatakan bahwa chlorhexidine memiliki efektivitas yang lebih baik dari teh hijau dengan konsentrasi 10%. Berdasarkan hasil data statistik teh hijau konsentrasi 25% sudah dapat memiliki efek Tabel 2 One Way Anova antibakteri yang setara dengan chlorhexidine glukonat 0,2% 11,12 .…”