RESUMO
AIM: To determine the effect of sodium bicarbonate (SB), sodium metaperiodate (SMP) and sodium dodecyl sulfate (SDS) combination on biofilm formation and dispersal in dental unit waterline (DUWL)-associated bacteria and yeast. METHODS AND RESULTS: The in vitro effect of SB, SMP and SDS alone and in combination on biofilm formation and dispersal in Pseudomonas aeruginosa, Klebsiella pneumoniae, Actinomyces naeslundii, and Candida albicans was investigated using a 96-well microtitre plate biofilm assay. The combination showed a broad-spectrum inhibitory effect on growth as well as biofilm formation of both gram-negative and gram-positive bacteria, and yeast. In addition, the SB + SMP + SDS combination was significantly more effective in dispersing biofilm than the individual compounds. The combination dispersed more than 90% of P. aeruginosa biofilm whereas the commercial products, Oxygenal 6, Sterilex Ultra, and PeraSafe showed no biofilm dispersal activity. CONCLUSION: The composition comprising SB, SMP, and SDS was effective in inhibiting as well as dispersing biofilms in DUWL-associated bacteria and yeast. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that a composition comprising environmentally friendly and biologically safe compounds such as SB, SMP, and SDS has a potential application in reducing DUWL-associated acquired infections in dental clinics.
Assuntos
Biofilmes/efeitos dos fármacos , Desinfetantes de Equipamento Odontológico/farmacologia , Desinfecção/métodos , Controle de Infecções Dentárias/métodos , Microbiologia da Água , Bactérias/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Mitógenos/farmacologia , Ácido Periódico/farmacologia , Bicarbonato de Sódio/farmacologia , Dodecilsulfato de Sódio/farmacologia , Tensoativos/farmacologia , Leveduras/efeitos dos fármacosRESUMO
The global regulatory system of Escherichia coli, carbon storage regulator (Csr), was engineered to increase the intracellular concentration of phosphoenolpyruvate. We examined the effects of csrA and csrD mutations and csrB overexpression on phenylalanine production in E. coli NST37 (NST). Overexpression of csrB led to significantly greater phenylalanine production than csrA and csrD mutations (2.33 vs 1.67 and 1.61 g l(-1), respectively; P < 0.01). Furthermore, the overexpression of csrB was confirmed by the observed increase in csrB transcription level. We also determined the effect of overexpressing transketolase A (TktA) or glucose-6-phosphate dehydrogenase (Zwf) in NST and the csrA mutant of NST (NSTCSRA) on phenylalanine production. The NSTCSRA strain overexpressing TktA (NSTCSRA [pTktA]) produced significantly more phenylalanine than that of Zwf (2.39 vs 1.61 g l(-1); P > 0.01). Furthermore, we examined the effect of overexpressing TktA, 3-deoxy-D: -arabino-heptulosonate-7-phosphate synthase (AroF(FR)), and chorismate mutase/prephenate dehydratase (PheA(FR)) together in NSTCSRA (NSTCSRA [pTkaFpA]). It is interesting to note that NSTCSRA [pTkaFpA] produced significantly less phenylalanine than both NSTCSRA [pTktA] and NST overexpressing csrB (NST [pCsrB]) (1.84 vs 2.39 and 2.33 g l(-1), respectively; P < 0.01). Thus, csrB overexpression or csrA mutation in combination with tktA overexpression was more effective than previous approaches that targeted the glycolytic or aromatic pathway enzymes for enhancing phenylalanine production.
Assuntos
Escherichia coli/genética , Escherichia coli/metabolismo , Regulação Bacteriana da Expressão Gênica , Fenilalanina/biossíntese , 3-Desoxi-7-Fosfo-Heptulonato Sintase/genética , 3-Desoxi-7-Fosfo-Heptulonato Sintase/metabolismo , Corismato Mutase/genética , Corismato Mutase/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Deleção de Genes , Perfilação da Expressão Gênica , Glucosefosfato Desidrogenase/genética , Glucosefosfato Desidrogenase/metabolismo , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Redes e Vias Metabólicas , Modelos Biológicos , Mutagênese Insercional , Prefenato Desidratase/genética , Prefenato Desidratase/metabolismo , RNA Bacteriano/biossíntese , RNA Longo não Codificante , RNA Mensageiro/biossíntese , RNA não Traduzido/genética , RNA não Traduzido/metabolismo , Proteínas de Ligação a RNA/genética , Proteínas de Ligação a RNA/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transcetolase/genética , Transcetolase/metabolismoRESUMO
AIMS: To determine the effect of a composition comprising ovotransferrin (OT), protamine sulfate (PS) and ethylenediaminetetraacetic acid (EDTA) on biofilm formation by catheter-associated bacteria. METHODS AND RESULTS: The in vitro activity of OT, PS and EDTA alone and in combinations against biofilm formation by Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Enterococcus faecalis and Staphylococcus epidermidis was investigated. All the three compounds either alone or in combinations failed to inhibit the growth completely at the concentrations tested. However, the subinhibitory concentrations of three compounds in a composition showed synergistic inhibitory effect on biofilm formation by K. pneumoniae, Ps. aeruginosa and S. epidermidis. Furthermore, 79-95% reduction in Ps. aeruginosa and S. epidermidis biofilm formation was observed in a clear vinyl urinary catheter treated with the composition. CONCLUSION: The subinhibitory concentrations of OT, PS and EDTA in a composition were effective in reducing biofilm formation by catheter-associated bacteria. SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that a synergistic composition-comprising non-antibiotic generally regarded as safe (GRAS) compounds such as OT, PS and EDTA may be used in the prevention of catheter-related infections.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Conalbumina/farmacologia , Ácido Edético/farmacologia , Protaminas/farmacologia , Biofilmes/crescimento & desenvolvimento , Cateterismo , Quelantes/farmacologia , Combinação de Medicamentos , Enterococcus faecalis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Proteus mirabilis/efeitos dos fármacos , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus epidermidis/efeitos dos fármacosRESUMO
A spectrofluorometric assay was developed for quantification of bacterial biofilms grown on a microtiter plate. The method involved staining biofilms formed by gram-negative and gram-positive bacteria with wheat germ agglutinin-Alexa Fluor 488 conjugate, which selectively binds to N-acetylglucosamine residues in biofilms. The fluorescence of stained biofilms was measured with a fluorescent plate reader. This method was compared with a widely used microplate colorimetric assay involving crystal violet staining of biofilms formed by both gram-negative and gram-positive bacteria. A strong linear association existed between the two methods (r (2)=0.99/0.94). Being more sensitive and specific as compared to colorimetric method, the spectrofluorometric assay provides a better alternative for quantification and characterization of bacterial biofilms.
