Brazilian scientists: much to learn from the microbial biofilm lifestyle (a resistant, resilient, well-orchestrated, and dynamic organization) / Cientistas brasileiros: muito a aprender com o estilo de vida do biofilme microbiano (uma organização resistente, resiliente, bem orquestrada e dinâmica)

Abstract In the present perspective, some parallels are drawn between a career as a scientist in Brazil and the ability of microorganisms to form a biofilm. Do these connections really exist? Definitely the answer is YES. Over billions of years, microbial biofilms have evolved in order to form a cohesive, well-structured, organized and dynamic community, which is characterized by its resistant/resilient profile to several environmental stressors. Adapting to constant change is a necessary attribute for survival and perpetuation of all live organisms, which are key signatures present in the hereditary molecule. Brazilian scientists are faced with many stressful situations along their journey in academia, which requires constant adaptability, reorganization and, above all, resilience. Can we take some lessons from what we know about the biofilm lifestyle developed by microorganisms? The answer is yes!

Resumo Na perspectiva atual, alguns paralelos são traçados entre a carreira de cientista no Brasil e a capacidade dos microrganismos de formarem biofilme. Essas conexões realmente existem? Definitivamente a resposta é SIM. Ao longo de bilhões de anos, os biofilmes microbianos evoluíram para formar uma comunidade coesa, bem estruturada, organizada e dinâmica, que se caracteriza por seu perfil de resistência/resiliência a diversos estressores ambientais. Adaptar-se a mudanças constantes é um atributo necessário para a sobrevivência e perpetuação de todos os organismos vivos, que são assinaturas-chave presentes na molécula de hereditariedade. Nesse sentido, os cientistas brasileiros se deparam com diversas situações estressantes ao longo de suas trajetórias na academia, exigindo constante adaptabilidade, reorganização e, acima de tudo, resiliência. Podemos tirar algumas lições do que sabemos sobre o estilo de vida do biofilme desenvolvido por microrganismos? A resposta é sim!

Antibacterial efficacy of essential oils of three aromatic plants in combination with povidone-iodine against Staphylococcus aureus grown in biofilm cultures.

Staphylococcus aureus, one of the opportunistic species responsible for clinical and / or bacteriological infections may react with biotic and abiotic surfaces and produces biofilm. In this form the bacteria become somewhat vulnerable to various physical and / or chemical antimicrobial agents. The aim of this study was to investigate the antibacterial efficacy of PVI, alone and in combination with essential oils (EO) of three aromatic plants, Eucalyptus globulus, Thymus capitatus, and Rosmarinus officinalis, against biofilms of four clinical isolates of Staphylococcus aureus from intravenous catheter associated infections. These strains isolated at the university hospital of Tlemcen, were characterized and identified, in a previous study, as strongly adherent using the microtiter plate method. Minimum inhibitory (MIC) and minimum bactericidal (MBC) concentrations of different essential oils sole and in combination with PVI for studied strains grown in biofilm, were determined by microbroth dilution method. The antibacterial effect of EOs and PVI, alone and in combination, against biofilmforming staphylococci, was also demonstrated. EO of E. globulus was more effective, in comparaison with the two other EOs. In addition, the antibacterial effects of the three EOs studied in combination with PVI were deemed synergistic against the biofilm of all tested strains, with a fractional inhibitory concentration index (FICI) <0.5. Accordingly, we could suggest the use of PVI in combination with EOs, especially of E. globulus ; since this EO was proved to be more efficacious in enhancing the antibacterial efficacy of PVI against biofilm of S. aureus.

Microbial Biofilm: Contamination in Dental Chair Unit.

This short review focuses on biofilms in the dental clinic environment. Microbial biofilms are potentially a significant source of contamination and cross-infection in the dental clinic. Biofilms in dental chair unit waterlines (DUWLs), suction hoses and fittings pose the most significant risk as these may come into contact with the patient during treatment. These can be managed effectively by regular disinfection using chemical and other methods to minimize reservoirs and disseminators of potentially pathogenic bacteria from these areas.

Biological activities of a mixture of biosurfactant from Bacillus subtilis and alkaline lipase from Fusarium oxysporum

In this study, we investigate the antimicrobial effects of a mixture of a biosurfactant from Bacillus subtilis and an alkaline lipase from Fusarium oxysporum (AL/BS mix) on several types of microorganisms, as well as their abilities to remove Listeria innocua ATCC 33093 biofilm from stainless steel coupons. The AL/BS mix had a surface tension of around 30 mN.m-1, indicating that the presence of alkaline lipase did not interfere in the surface activity properties of the tensoactive component. The antimicrobial activity of the AL/BS mix was determined by minimum inhibitory concentration (MIC) micro-assays. Among all the tested organisms, the presence of the mixture only affected the growth of B. subtilis CCT 2576, B. cereus ATCC 10876 and L. innocua. The most sensitive microorganism was B. cereus (MIC 0.013 mg.mL-1). In addition, the effect of the sanitizer against L. innocua attached to stainless steel coupons was determined by plate count after vortexing. The results showed that the presence of the AL/BS mix improved the removal of adhered cells relative to treatment done without the sanitizer, reducing the count of viable cells by 1.72 log CFU.cm-2. However, there was no significant difference between the sanitizers tested and an SDS detergent standard (p<0.05).